DEFORMABLE BATTERY HOUSING

Abstract

Assembly for an electrified vehicle, comprising the following: a bottom wall of a battery housing, wherein the bottom wall comprises a bottom wall deformation area, and wherein the bottom wall deformation area is designed to accommodate an exhaust pipe of an electrified vehicle and to deform in response to the load ahead of other areas of the bottom wall; and an upper wall of the battery housing, wherein the upper wall includes an upper wall deformation area designed to deform before other areas of the upper wall in response to a load being applied to the battery housing; and a first array of battery cells on a first lateral side of the upper wall deformation area and a second array of battery cells on an opposite second lateral side of the upper wall deformation area.

Description

TECHNICAL FIELD

[0001] This disclosure relates generally to a battery pack housing, and more particularly to a battery pack housing including regions for controlled deformation under a side impact load. STATE OF THE ART

[0002] Electrified vehicles differ from conventional motor vehicles in that they are selectively powered using one or more electric motors powered by a traction battery. The electric motors can power the electrified vehicles instead of, or in addition to, an internal combustion engine. Examples of electrified vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs), and battery electric vehicles (BEVs).

[0003] US 2015 0 207 119 A1 describes an assembly for an electrified vehicle, comprising a bottom wall of a battery housing, a top wall of the battery housing, a top wall deformation region that deforms in response to loading, and two arrays of battery cells on opposite lateral sides of the top wall deformation region. It is further described that a bottom wall deformation region of the bottom wall deforms in response to loading. Further relevant prior art relating to the background of the invention is provided by DE 10 2012 000 622 A1.

[0004] The traction batteries of a typical electrified vehicle contain arrays of battery cells housed within a protective enclosure. Relatively high loads, such as side impact loads on the electrified vehicle, can undesirably disrupt the traction batteries, even when the arrays are housed within an enclosure. The traction batteries can have a relatively large package footprint. SUMMARY

[0005] An assembly for an electrified vehicle according to an exemplary aspect of the present disclosure includes, among other things, a bottom wall of a battery housing and a top wall of the battery housing. The top wall includes a top wall deformation region configured to deform prior to other regions of the top wall in response to a load being applied to the battery housing.

[0006] In a further non-limiting embodiment of the assembly for an electrified vehicle, the assembly may include a first array of battery cells on a first lateral side of the top wall deformation region and a second array of battery cells on an opposite second lateral side of the top wall deformation region.

[0007] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the assembly may include a bottom wall deformation region of the bottom wall. The bottom wall deformation region is configured to deform in response to loading prior to other regions of the bottom wall.

[0008] In a further non-limiting embodiment of any of the foregoing electrified vehicle assemblies, the underbody deformation region receives an exhaust pipe of an electrified vehicle.

[0009] In a further non-limiting embodiment of any of the foregoing electrified vehicle assemblies, the first array is located on a first lateral side of the underwall deformation region and the second array is located on an opposite second lateral side of the underwall deformation region.

[0010] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the first array and the second array are spaced from all portions of the underwall deformation region.

[0011] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the underbody deformation region is a tunnel extending from a first planar portion and a second planar portion of the underbody.

[0012] In a further non-limiting embodiment of any of the foregoing electrified vehicle assemblies, the first array is disposed on the first planar portion and the second array is disposed on the second planar portion.

[0013] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the assembly includes an electrified vehicle. The battery housing is mounted beneath a floor pan of the electrified vehicle between a front axle and a rear axle.

[0014] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the battery housing is attached to the electrified vehicle between the front axle and a landing area of ​​the floor pan.

[0015] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the battery housing is laterally mounted between a first side sill and an opposite second side sill.

[0016] In a further non-limiting embodiment of any of the foregoing assemblies for an electrified vehicle, the load is a side load.

[0017] A method for absorbing a side load with a battery pack according to another exemplary aspect of the present disclosure includes, among other things, deforming a top wall deformation region within a top wall of a battery pack housing in response to a side load being applied to the battery pack housing. The top wall deformation region is configured to deform forward of a first planar portion of the top wall located on a first side of the top wall deformation region and forward of a second planar portion of the top wall located on an opposite second side of the top wall deformation region.

[0018] In a further non-limiting embodiment of the foregoing methods, the method includes deforming a bottom wall deformation region within a bottom wall of a battery pack housing in response to a side load being applied to the battery pack housing. The bottom wall deformation region is configured to deform forward of a first planar portion of the bottom wall located on a first side of the bottom wall deformation region and forward of a second planar portion of the bottom wall located on an opposite second side of the bottom wall deformation region.

[0019] In a further non-limiting embodiment of any of the foregoing methods, the method includes submerging an exhaust pipe of an electrified vehicle within the underbody deformation region.

[0020] In a further non-limiting embodiment of any of the foregoing methods, the method includes positioning a first array of battery cells on a first planar portion of the bottom wall and a second array of battery cells on the second planar portion of the bottom wall, the first and second arrays being spaced from all portions of the bottom wall deformation region.

[0021] In a further non-limiting embodiment of any of the foregoing methods, the bottom wall deformation region is a tunnel extending relative to the first planar portion and a second planar portion of the bottom wall.

[0022] In a further non-limiting embodiment of any of the foregoing methods, the method includes mounting the battery pack enclosure beneath a floor pan of an electrified vehicle between a front axle and a rear axle.

[0023] In a further non-limiting embodiment of any of the foregoing methods, the method includes mounting the battery pack housing to the electrified vehicle between the front axle and a landing area of ​​the floor pan.

[0024] In a further non-limiting embodiment of any of the foregoing methods, the method includes mounting the battery pack housing between a first side sill and an opposite second side sill. SHORT DESCRIPTION OF THE CHARACTERS

[0025] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures accompanying the detailed description may be briefly described as follows: Fig. 1 shows an example powertrain for an electrified vehicle. Fig. Figure 2 shows a side profile of an exemplary electrified vehicle incorporating the powertrain from Fig. 1 contains. Fig. 3 shows a front view of the electrified vehicle from Fig. 2. Fig. 4 shows a perspective view of a battery pack from the powertrain of Fig. 1. Fig. Figure 5 shows a perspective view of the battery pack of Fig. 4, which is located in a floor pan of the electrified vehicle from Fig. 2 is mounted. Fig. 6 shows a bottom view of the floor pan from Fig. 4. Fig. Figure 7 shows a sectional view along line 7-7 in Fig. 4. Fig. Figure 8 shows an energy management model based on the sectional view of Fig. 7 refers. DETAILED DESCRIPTION

[0026] This disclosure generally relates to a battery pack. A housing of the battery pack includes deformation regions that deform in response to a load above a threshold. The deformation regions facilitate controlled deformation of the battery pack under load to absorb energy. The controlled deformation protects arrays of battery cells within the battery pack.

[0027] With reference to Fig. 1, a powertrain 10 of a hybrid electric vehicle (HEV) includes a battery pack 14 having a housing 16 with a plurality of battery arrays 18. The exemplary battery pack 14 is a high-voltage battery pack capable of providing power to propel the HEV.

[0028] The powertrain 10 further includes an internal combustion engine 20, a motor 22, and a generator 24. The motor 22 and generator 24 are types of electric machines. The motor 22 and generator 24 may be separate or may take the form of a combined motor / generator.

[0029] In this embodiment, the powertrain 10 is a power-split powertrain employing a first drive system and a second drive system. The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels 28. The first drive system includes a combination of the internal combustion engine 20 and the generator 24. The second drive system includes at least the motor 22, the generator 24, and the battery pack 14. The motor 22 and the generator 24 are parts of an electric drive system of the powertrain 10.

[0030] The engine 20 and the generator 24 may be connected by a power transfer unit 30, such as a planetary gear set. Of course, other types of power transfer units, including other gear sets and transmissions, may also be used to connect the engine 20 to the generator 24. In one non-limiting embodiment, the power transfer unit 30 is a planetary gear set including a ring gear 32, a sun gear 34, and a carrier assembly 36.

[0031] The generator 24 can be driven by the internal combustion engine 20 through the power transmission unit 30 to convert kinetic energy into electrical energy. Alternatively, the generator 24 can function as a motor to convert electrical energy into kinetic energy, thereby delivering torque to a shaft 38 connected to the power transmission unit 30.

[0032] The ring gear 32 of the power transfer unit 30 is connected to a shaft 40, which is connected to the vehicle drive wheels 28 by a second power transfer unit 44. The second power transfer unit 44 may include a gear set with a plurality of gears 46. Other power transfer units could be used in other examples.

[0033] The gears 46 transmit torque from the internal combustion engine 20 to a differential 48 to ultimately provide traction to the vehicle drive wheels 28. The differential 48 may include a plurality of gears that facilitate the transmission of torque to the vehicle drive wheels 28. In this example, the second power transfer unit 44 is mechanically coupled to an axle 50 through the differential 48 to distribute torque to the vehicle drive wheels 28.

[0034] The motor 22 can be selectively used to drive the vehicle's drive wheels 28 by delivering torque to a shaft 54, which is also connected to the second power transfer unit 44. In this embodiment, the motor 22 and the generator 24 cooperate as part of a regenerative braking system in which both the motor 22 and the generator 24 can be used as motors to deliver torque. For example, the motor 22 and the generator 24 can each deliver electrical power to charge cells of the battery pack 14.

[0035] With reference to Fig. 2 and Fig. 3, an electrified vehicle 60 includes the drive train 10 of Fig. 1. In this example, the battery pack 14 is mounted on a floor pan 64 of the vehicle 60. As shown in Fig. 2, the battery pack 14 is positioned between a front axle 68 and a rear axle 72 of the vehicle 60. As shown in Fig. 2, the battery pack 14 is positioned between a first rocker 74 on a first side of the vehicle 60 and a second rocker 76 on an opposite second side of the vehicle 60. The battery pack 14 may be directly attached to the first rocker 74 and the second rocker 76 in some examples.

[0036] We now refer to Fig. 4, in which the housing 16 of the battery pack 14 includes a top wall 88 or cover and a bottom wall 92 or shelf. The side walls 96 extend between the top wall 88 and the bottom wall 92. The housing forms an open area that accommodates a plurality of battery arrays 18. In this example, the top wall 88 is attached to upwardly facing surfaces of the side walls 96 to enclose the arrays 18 within the housing 16.

[0037] We now refer to the Fig. 5 and Fig. 6 and continue on Fig. 4, wherein the battery pack 14 is mounted within the vehicle 60 such that the top wall 88 bears against a downwardly facing surface 90 of the floor pan 64. The battery pack 14 may be attached to the floor pan 64, for example, using mechanical fasteners.

[0038] The floor pan 64 generally includes a front portion 100, a midportion 104, and a rear portion 108. The front portion 100 extends from a front edge 112 of the floor pan 64 to a position aligned with the front axle 68. The midportion 104 extends from the position aligned with the front axle 68 to a shoulder 116 of the floor pan 64. The midportion 108 extends from the shoulder 116 to a rear edge 120 of the floor pan 64.

[0039] In this example, the battery pack 14 is secured to the central portion 104 of the floor pan 64 such that the battery pack 14 is positioned between the front axle 68 and the shoulder 116 when the battery pack 14 is in an installed position. The shoulder 116, in this example, is aligned with a front edge of a rear passenger seat within a passenger compartment of the vehicle 60.

[0040] The floor pan 64 includes a tunnel 124 that allows an exhaust pipe 128 to be vertically raised while maintaining a suitable clearance from the floor pan 64. The exemplary exhaust pipe 128 carries combustion products produced by the internal combustion engine 20 ( Fig. 1). Tunnel 124 may also provide clearance for a 12 V cable, a brake cable, a fuel line bundle, etc.

[0041] The floor pan 64 may be used in the electrified vehicle 60 as shown or may be used in a conventional vehicle that does not have a traction battery pack. Using a common design for the floor pan 64 in both a conventional vehicle and the electrified vehicle 60 may, among other things, reduce manufacturing costs and complexity associated with manufacturing the floor pan 64.

[0042] In this example, the top wall 88 of the housing 16 includes a top wall deformation region 128 that extends into the tunnel 124 when the battery pack 14 is in the installed position. In other examples, the top wall deformation region 128 extends toward the tunnel 124, but not into it. In other examples, the top wall deformation region 128 is generally planar or extends downwardly. The bottom wall 92 includes an exemplary bottom wall deformation region 132 that extends upwardly toward the tunnel 124. In other examples, the bottom wall deformation region 132 is generally planar or extends downwardly.

[0043] In this example, the underbody deformation region 132 forms a housing tunnel 136 that at least partially accommodates a portion of the exhaust pipe 128. This creates a clearance between the exhaust pipe 128 and the ground. The exemplary exhaust pipe 128 is part of a centerline exhaust system.

[0044] The lower wall deformation region 132 is aligned with the upper wall deformation region 128. The lower wall deformation region 132 extends upwardly more than the upper wall deformation region 128 such that the housing 16 has a narrower vertical cross-section of the housing 16 at and near a vehicle lateral centerline position.

[0045] We now refer to the cross-sectional side view of Fig. 7, wherein the exemplary top wall deformation region 128 extends upwardly from a first generally planar portion 140 of the top wall 88 and a second generally planar portion 142 of the top wall 88. The bottom wall deformation region 132 extends upwardly from a first generally planar portion 146 of the bottom wall 92 and a second generally planar portion 150 of the bottom wall 92.

[0046] The upper wall deformation region 128 is positioned laterally between the first planar portion 140 and the second planar portion 142. The lower wall deformation region 132 is positioned laterally between the first planar portion 146 and the second planar portion 150. The upper wall deformation region 128 and the lower wall deformation region 132 are laterally aligned in this example.

[0047] In this example, at least a first array 18a of battery cells is disposed on the first planar portion 146, and at least a second array 18b of battery cells is disposed on the second planar portion 150. Note that the first array 18a and the second array 18b are spaced apart from all portions of the bottom wall deformation region 132.

[0048] A side impact to a first side of the electrified vehicle may exert a force F1 on the battery pack 14 through the first rocker 74. A side impact to an opposite second side of the electrified vehicle 60 may exert a force F2 on the battery pack 14 through the second rocker 76.

[0049] If the force F1 on the housing 16 exceeds a threshold value, at least the top wall deformation region 128 of the housing 16 begins to deform. A designer of the housing 16 could adjust the desired threshold value by strengthening or weakening the deformation region 128. The threshold value could be adjusted to loads for specific vehicle programs.

[0050] In this example, the geometry of the top wall deformation region 128 causes the top wall deformation region 128 to deform in response to the force F1 before other portions of the top wall 88. This allows the top wall 88 to absorb the force F1 without affecting portions of the top wall 88 proximate to the arrays 18a and 18b. In this example, the top wall deformation region 128 bends and folds upward into the tunnel 124 in response to the force F1.

[0051] If the force F1 exceeds a threshold, at least the bottom wall deformation region 132 of the housing 16 begins to deform. In this example, the geometry of the bottom wall deformation region 132 causes the bottom wall deformation region 132 to deform in response to the force F1 before other portions of the bottom wall 92.

[0052] The top wall deformation region 128 and the bottom wall deformation region 132 cause the battery pack housing 16 to deform in a controlled manner in response to a side load above the threshold. Focusing the deformation on the top wall deformation region 128 and the bottom wall deformation region 132 can reduce interference with the arrays 18a and 18b.

[0053] Although the geometries of the top wall deformation region 128 and the bottom wall deformation region 132 cause the controlled deformation in this example, other techniques could be used to provide the controlled deformation in the top wall deformation region 128 and the bottom wall deformation region 132. For example, the top wall deformation region 128 could be generally planar but made of a weaker material than the generally planar portion 140 and the generally planar portion 142. The top wall deformation region 128 could be a generally planar portion of the top wall 88 that is thinned to weaken the top wall deformation region 128 relative to other portions of the top wall 88. The bottom wall deformation region 132 could similarly be generally planar and made of a weaker or thinner material relative to the generally planar portion 146 and the generally planar portion 150.

[0054] Fig. 8 shows an energy management model of the cross section of Fig. 7, when the force F1 is applied to the electrified vehicle 60. R1 represents a resistance to the force F1, which is applied by a side wall 96a of the battery pack housing 16. R2 represents a resistance to the force F1, which is applied by a transverse front element 160 ( Fig. 4 and Fig. 5) of the floor pan 64. R3 represents a resistance to force F1 offered by a transverse tail member 164 of the floor pan 64. R4 represents a resistance to force F1 offered by the first planar portion 140 of the top wall 88 and the first planar section 146 of the bottom wall 92. R6 represents a resistance to force F1 offered by the second planar section 142 of the top wall 88 and the second planar section 150 of the bottom wall 92. R5 represents a resistance to force F1 offered by the top wall deformation region 128 of the top wall 88 and the bottom wall deformation region 132 of the bottom wall 92. R7 represents resistance to force F1 offered by the frame structure of the floor pan 64 and a side wall 96b of the housing 16.

[0055] M1 represents array 18a, and M2 represents array 18b. C1 represents the clearance between array 18a and sidewall 96a. C2 represents the clearance between array 18a and array 18b. C3 represents the clearance between array 18b and sidewall 96b.

[0056] As shown, resistor R5 is smaller than each of resistors R1, R2, R3, R4, R6, and R7. Thus, when force F1 is applied, the housing 16 yields and deforms within the top wall deformation region 128, the bottom wall deformation region 132, or both. This provides a controlled deformation of the housing 16 that can maintain the clearances C1, C2, and C3 to reduce interference with the arrays 18a and 18b.

[0057] In addition to the upper wall deformation area 124 and the lower wall deformation area 132, the area formed by the sills 74 and 76 (in Fig.8 not shown) must be smaller than the resistors R1-R7, so that the sills 74 and 76 deform and collapse in front of the housing 16 in response to the force F1 or F2.

[0058] Features of the disclosed examples include a battery pack spanning from a first rocker to an opposite second rocker. The battery pack has deformation regions to provide controlled deformation of the battery pack under a side load. The deformation is concentrated in desired areas to avoid interference with the battery cell arrays within a battery pack enclosure. The exemplary battery pack includes deformation regions in a central region of the battery pack to provide the battery pack with a "soft" center. The exemplary battery pack accommodates side impact loads by deforming into a tunnel of the floor pan.

[0059] The foregoing description is exemplary and not restrictive. Variations and modifications of the disclosed examples may be apparent to those skilled in the art without necessarily departing from the spirit of the present disclosure. Thus, the legal scope of protection afforded by the present disclosure can only be determined by a careful examination of the following claims.

Claims

[1] Assembly for an electrified vehicle, comprising: a bottom wall of a battery housing, the bottom wall comprising a bottom wall deformation region of the bottom wall, and the bottom wall deformation region being configured to receive an exhaust pipe of an electrified vehicle and to deform in response to loading prior to other regions of the bottom wall; and a top wall of the battery case, the top wall including a top wall deformation region configured to deform prior to other regions of the top wall in response to a load being applied to the battery case; and a first array of battery cells on a first lateral side of the top wall deformation region and a second array of battery cells on an opposite second lateral side of the top wall deformation region. [2] The electrified vehicle assembly of claim 1, wherein the first array is located on a first lateral side of the underwall deformation region and the second array is located on an opposite second lateral side of the underwall deformation region. [3] The electrified vehicle assembly of claim 2, wherein the first array and the second array are spaced from all parts of the bottom wall deformation region. [4] An electrified vehicle assembly according to claim 1, wherein the bottom wall deformation region is a tunnel extending upwardly from a first planar portion and a second planar portion of the bottom wall. [5] The electrified vehicle assembly of claim 4, wherein the first array is disposed on the first planar portion and the second array is disposed on the second planar portion. [6] The assembly for an electrified vehicle of claim 1, further comprising an electrified vehicle, wherein the battery housing is mounted below a floor pan of the electrified vehicle between a front axle and a rear axle. [7] An assembly for an electrified vehicle according to claim 6, wherein the battery housing is attached to the electrified vehicle between the front axle and a shoulder region of the floor pan. [8] An assembly for an electrified vehicle according to claim 6 or 7, wherein the battery housing is laterally mounted between a first side sill and an opposite second side sill. [9] An assembly for an electrified vehicle according to any one of the preceding claims, wherein the load is a side load. [10] A method for absorbing a side load with a battery pack, comprising the following step: Deforming a top wall deformation region within a top wall of a battery pack housing and a bottom wall deformation region within a bottom wall of a battery pack housing in response to a side load applied to the battery pack housing, wherein the top wall deformation region is configured to deform in advance of a first planar portion of the top wall located on a first side of the top wall deformation region and in advance of a second planar portion of the top wall located on an opposite second side of the top wall deformation region, and wherein the bottom wall deformation region is configured to deform in advance of a first planar portion of the bottom wall located on a first side of the bottom wall deformation region and in advance of a second planar portion of the bottom wall located on an opposite second side of the bottom wall deformation region; and the submerging of an exhaust pipe of an electrified vehicle within the underbody deformation area. [11] The method of claim 10, further comprising positioning a first array of battery cells on a first planar portion of the bottom wall and a second array of battery cells on the second planar portion of the bottom wall, the first and second arrays being spaced from all portions of the bottom wall deformation region. [12] The method of claim 11, wherein the bottom wall deformation region is a tunnel extending upward relative to the first planar portion and the second planar portion of the bottom wall. [13] The method of any one of claims 10 to 12, further comprising mounting the battery pack housing beneath a floor pan of an electrified vehicle between a front axle and a rear axle. [14] The method of claim 13, further comprising mounting the battery pack housing on the electrified vehicle between the front axle and a shoulder portion of the floor pan. [15] The method of claim 13 or 14, further comprising mounting the battery pack housing laterally between a first side sill and an opposite second side sill.

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