Connected battery pack assembly and connecting method

A connected assembly can include, among other things, first and second side rails of a battery pack of an electrified vehicle. The battery pack including a plurality of battery arrays disposed between the first and second side rails within an enclosure assembly. The connected assembly further includes a lateral rail extending from the first side rail to the second side rail, and a bracket assembly directly connected to the first side rail and the lateral rail. A battery pack connection method can include, among other things, directly connecting a bracket assembly to a horizontally facing side of a lateral rail, and directly connecting the bracket assembly to a horizontally facing side of a first side rail of an enclosure assembly that holds a battery pack of an electrified vehicle between the first side rail and a second side rail.

TECHNICAL FIELD

This disclosure relates generally to a connected assembly and, more particularly, to a connected assembly having a bracket that secures together areas of a battery pack.

BACKGROUND

Generally, electrified vehicles can differ from conventional motor vehicles because electrified vehicles are selectively driven using one or more battery-powered electric machines. Conventional motor vehicles, in contrast to electrified vehicles, are driven exclusively with an internal combustion engine. Electrified vehicles may use electric machines instead of, or in addition to, the internal combustion engine.

Example electrified vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles, and battery electric vehicles (BEVs). A powertrain for an electrified vehicle can include a high-voltage battery pack having battery cells that store electric power for powering the electric machines and other electrical loads of the electrified vehicle. The battery pack can be secured to an underbody, or another area, of an electrified vehicle.

SUMMARY

A connected assembly according to an exemplary aspect of the present disclosure includes, among other things, first and second side rails of a battery pack of an electrified vehicle. The battery pack including a plurality of battery arrays disposed between the first and second side rails within an enclosure assembly. The connected assembly further includes a lateral rail extending from the first side rail to the second side rail, and a bracket assembly directly connected to the first side rail and the lateral rail.

In another example of the preceding connected assembly, the bracket assembly is a first bracket assembly. The connected assembly further includes a second bracket assembly directly connected to the second side rail and the lateral rail.

In another example of any of the preceding connected assemblies, the lateral rail interfaces with the first rail along a vertically extending interface. Also, the bracket assembly extends over the vertically extending interface.

In another example of any of the preceding connected assemblies, the bracket assembly is directly connected to a horizontally facing side of the first side rail and a horizontally facing side of the lateral rail.

In another example of any of the preceding connected assemblies, the lateral rail is a first lateral rail that is rearward of the enclosure assembly relative to an orientation of the electrified vehicle.

In another example of any of the preceding connected assemblies, the battery pack is secured to an underbody of the electrified vehicle.

Another example of any of the preceding connected assemblies includes a driver side vehicle rocker and a passenger side vehicle rocker. The first side rail is secured directly to the driver side vehicle rocker. The second side rail is secured directly to the passenger side vehicle rocker.

In another example of any of the preceding connected assemblies, the bracket is directly connected to a horizontally facing side of the first side rail and a vertically facing side of the lateral rail.

In another example of any of the preceding connected assemblies, the bracket is a single, continuous bracket.

Another example of any of the preceding connected assemblies includes at least one fastener having a head and a shaft extending from the head. The head is held by the bracket between the bracket and the lateral rail. The shaft extends through an aperture in the bracket.

Another example of any of the preceding connected assemblies includes a suspension component of the electrified vehicle. The at least one fastener is secured directly to the suspension component.

A battery pack connection method according to another exemplary aspect of the present disclosure includes, among other things, directly connecting a bracket assembly to a horizontally facing side of a lateral rail, and directly connecting the bracket assembly to a horizontally facing side of a first side rail of an enclosure assembly. The enclosure assembly holding a plurality of battery arrays of an electrified vehicle between the first side rail and a second side rail.

In another example of the preceding method, the bracket assembly is a first bracket assembly. The method further includes directly connecting a second bracket assembly to a horizontally facing side of the second side rail and to the horizontally facing side of the lateral rail.

In another example of any of the preceding methods, the lateral rail extends from the first side rail to the second side rail.

In another example of any of the preceding methods, the lateral rail interfaces with the first rail along a vertically extending interface. Also, the bracket assembly extends over the vertically extending interface.

In another example of any of the preceding methods, the lateral rail is a first lateral rail that is rearward of the enclosure assembly relative to an orientation of the electrified vehicle.

Another example of any of the preceding methods, includes securing the enclosure assembly to an underbody of the electrified vehicle.

Another example of any of the preceding methods includes securing the first side rail to a driver side vehicle rocker, and securing the second side rail to a passenger side vehicle rocker.

Another example of any of the preceding methods includes using the bracket to hold at least one head of a fastener between the bracket and the horizontally facing side of the lateral rail. The fastener includes a shaft that extends through an aperture in the bracket.

Another example of any of the preceding methods, includes securing the shaft of the fastener to a suspension component of the electrified vehicle.

DETAILED DESCRIPTION

This disclosure details a connected assembly that secures areas of a battery pack. The connected assembly can help the battery pack to withstand a load, such as a side impact load resulting from a pole impact, without exposing components within an interior of the battery pack.

FIG. 1schematically illustrates a powertrain10for an electrified vehicle. Although depicted as a hybrid electrified vehicle (HEV), it should be understood that the concepts described herein are not limited to HEVs and could extend to other electrified vehicles, including, but not limited to, plug-in hybrid electrified vehicles (PHEVs), fuel cell vehicles (FCVs), and battery electrified vehicles (BEVs).

In one embodiment, the powertrain10is a powersplit powertrain system that employs a first drive system and a second drive system. The first drive system includes a combination of an engine14and a generator18(i.e., a first electric machine). The second drive system includes at least a motor22(i.e., a second electric machine), the generator18, and a battery pack24. In this example, the second drive system is considered an electric drive system of the powertrain10. The first and second drive systems generate torque to drive one or more sets of vehicle drive wheels28of the electrified vehicle.

The engine14, which is an internal combustion engine in this example, and the generator18may be connected through a power transfer unit30. In one non-limiting embodiment, the power transfer unit30is a planetary gear set that includes a ring gear32, a sun gear34, and a carrier assembly36. Of course, other types of power transfer units, including other gear sets and transmissions, may be used to connect the engine14to the generator18.

The generator18can be driven by engine14through the power transfer unit30to convert kinetic energy to electrical energy. The generator18can alternatively function as a motor to convert electrical energy into kinetic energy, thereby outputting torque to a shaft38connected to the power transfer unit30. Because the generator18is operatively connected to the engine14, the speed of the engine14can be controlled by the generator18.

The ring gear32of the power transfer unit30may be connected to a shaft40, which is connected to vehicle drive wheels28through a second power transfer unit44. The second power transfer unit44may include a gear set having a plurality of gears46. Other power transfer units may also be suitable. The gears46transfer torque from the engine14to a differential48to ultimately provide traction to the vehicle drive wheels28. The differential48may include a plurality of gears that enable the transfer of torque to the vehicle drive wheels28. In this example, the second power transfer unit44is mechanically coupled to an axle50through the differential48to distribute torque to the vehicle drive wheels28.

The motor22(i.e., the second electric machine) can also be employed to drive the vehicle drive wheels28by outputting torque to a shaft52that is also connected to the second power transfer unit44. In one embodiment, the motor22and the generator18cooperate as part of a regenerative braking system in which both the motor22and the generator18can be employed as motors to output torque. For example, the motor22and the generator18can each output electrical power to the battery pack24.

The battery pack24is an example type of electrified vehicle battery assembly. The battery pack24may have the form of a high-voltage battery that is capable of outputting electrical power to operate the motor22and the generator18. Other types of energy storage devices and/or output devices can also be used with the electrified vehicle having the powertrain10. The battery pack24is a traction battery pack as the battery pack24can provides power to drive the vehicle drive wheels28. The battery pack24includes a plurality of battery arrays54each including a plurality of individual battery cells.

Referring toFIG. 2, the battery pack24can be secured adjacent to an underbody58of an electrified vehicle62. When secured to the underbody58, the battery pack24is vertically below a passenger compartment of the electrified vehicle62and horizontally between front and rear wheels of the electrified vehicle62. Vertical and horizontal, for purposes of this disclosure, are with reference to the general orientation of the electrified vehicle62during ordinary operation, and with reference to ground.

With reference toFIG. 3, the battery pack24includes an enclosure assembly66that houses the battery arrays54. The enclosure assembly66includes a cover or lid70that is vertically above the battery arrays54. A first side rail74provides a side of the enclosure assembly66on a driver side of the battery pack24. A second side rail78provides a side of the enclosure assembly66on a passenger side of the battery pack24. The first side rail74and the second side rail78can be considered battery rails. The first side rail74and the second side rail78each extend longitudinally from a forward portion of the electrified vehicle62to a rearward portion of the electrified vehicle62.

To help secure the battery pack24to the electrified vehicle62, the first side rail74can be secured to a driver side rocker82, which is shown inFIG. 2. Mechanical fasteners such as bolts86can extend through apertures90in the first side rail74to threadably engage the driver side rocker82thereby securing the first side rail74to the driver side rocker82. Other mechanical fasteners can be used to similarly secure the second side rail78to a passenger side rocker of the electrified vehicle62.

The battery pack24further includes a rear lateral rail94that extends from the first side rail74to the second side rail78. The rear lateral rail94is a first lateral rail that is aft the battery arrays54relative to general orientation of the electrified vehicle62. A forward lateral rail98can extend from the first side rail74to the second side rail78. The forward lateral rail98is forward the battery arrays54relative to a general orientation of the electrified vehicle62.

The first side rail74, the second side rail78, the rear lateral rail94, and the second lateral rail98can be extruded from aluminum, for example. In another example, a metal or metal alloy other than aluminum could be used. Further, the first side rail74, the second side rail78, the rear lateral rail94, and the second lateral rail98could be formed by a process other than extrusion.

With reference now toFIG. 4, the battery pack24is shown secured adjacent to the underbody58after a load L has been applied to a driver side of the electrified vehicle62. The load L can be a side impact load, for example.

One example of a side impact load includes loads applied to the electrified vehicle62when a side of the electrified vehicle62contacts a pole. To simulate this contact, the electrified vehicle62can be moved relative to a pole until that pole contacts a laterally facing side of the electrified vehicle62.

The load L is high enough to deform at least portions of the driver side rocker82and the first side rail74. If not accounted for, the load L can cause the first side rail74to separate from the rear lateral rail94, as shown inFIG. 5.

In particular, the first side rail74interfaces with the rear lateral rail94at a vertically extending interface shown inFIG. 5. The load L, if not accounted for, can result in separation along this interface. The separation can introduce an opening O, which may undesirably expose components within the interior of the battery pack24, such as, for example, the battery arrays54.

With reference now toFIGS. 6-10, the battery pack24incorporates a connected assembly to reduce the likelihood of the first side rail74separating from the rear lateral rail94when under a load, such as the side impact load L ofFIG. 4.

The connected assembly includes, among other things, a bracket assembly100that is directly connected to both the first side rail74and the rear lateral rail94. The bracket assembly100is a first bracket assembly in the exemplary embodiment, and is located in the driver side of the electrified vehicle62. The bracket assembly100extends over at least a portion of the vertically extending interface where the first side rail74interfaces with the rear lateral rail94. The first side rail74can be joined to the rear lateral rail94along the vertically extending interface. The first side rail74could be welded to the rear lateral rail94, for example.

The connected assembly can further include a second bracket assembly104that is disposed on a passenger side of the electrified vehicle62. The second bracket assembly104is directly connected to the second side rail78and the rear lateral rail94. The second bracket assembly104can inhibit separation of the second side rail78from the rear lateral rail94due to, for example, an impact load applied to a passenger side of the electrified vehicle62.

Referring again to the bracket assembly100, directly connecting the bracket assembly100to the first side rail74includes, in this example, welding a portion108of the bracket assembly100to a horizontally facing side112of the first side rail74. The horizontally facing side112faces laterally outward away from the vehicle. The bracket assembly100is further secured to the first side rail74utilizing a portion114of the bracket which is welded directly to a vertically facing side116of the first side rail.

The bracket assembly100is directly connected to the rear lateral rail94via welds that secure a flange120to a horizontally facing side124of the rear lateral rail94.

The welds securing the bracket assembly100to the first side rail74and the rear lateral rail94can include multiple weld beads to increase stiffness.

During application of a load, such as the load L ofFIG. 4, the bracket assembly100helps to constrain movement of the first side rail74relative to the rear lateral rail94. This prevents the vertically extending interface between the first side rail74and the rear lateral rail94from opening as shown inFIG. 5. That is, the bracket assembly100helps to prevent shear.

In particular, the bracket assembly100can stabilize areas of the battery pack24and pull the battery pack24away from the impact zone near the where the load L is applied to the electrified vehicle62.

A portion128of the bracket assembly100is spaced rearward from the flange120. This establishes a cup shape in this area of the bracket assembly100. The cup shape results in an open area between the portion128and the horizontally facing side124of the rear lateral rail94when the flange120is secured to the horizontally facing side124.

The open area can accommodate the heads130of fasteners132. Shafts136of the fasteners extend through openings in the portion128to project rearward of the portion128while the heads130are captured between the horizontally facing side124and the portion128.

In the exemplary embodiment, portions of the shafts136are threaded. When the battery pack24is secured to the electrified vehicle62, the shafts136are each received within a respective slot140(FIG. 7) of a suspension component144of the electrified vehicle62. The suspension component is a rear subframe component in this example.

Torqueing down nuts148that threadably engage the shafts136clamps a portion of the suspension component144between the respective nut148and the portion128of the bracket assembly100. This can help to secure the bracket assembly100relative to the suspension component144. Since the bracket assembly100is secured to the rear lateral rail94and the first side rail74, the securing further helps to hold the battery pack24relative to the suspension component144.

Although the exemplary embodiment describes securing the bracket assembly100to the suspension component144, other embodiments may no secure the bracket assembly100to the suspension component144or any other suspension component.

In the exemplary embodiment, the bracket assembly100incorporates strengthening ribs152that are formed into the geometry of the bracket assembly100. The bracket assembly100can be stamped aluminum, or another metal or metal alloy, such as steel. The ribs152can be stamped into the bracket assembly100to reduce processing time.

With reference toFIGS. 11-13, another exemplary bracket assembly100A can be used to secure the first side rail74relative to the rear lateral rail94. The bracket assembly100A differs from the bracket assembly100in that the bracket assembly100A is a two-piece design.

The bracket assembly100A includes a cup feature156having the flange120A that is secured to the rear lateral rail94. The portion128A is provided by a separate piece of the bracket assembly100A.

The portion128A is secured relative to the flange120A when the fasteners132are secured to the suspension component. In some examples, the portion128A could be spot welded to the flange120A prior to securing the fasteners132to the suspension component144.

Like the bracket assembly100, the bracket assemblies100A can be stamped aluminum, or another metal or metal alloy, such as steel. The ribs152can be stamped into the bracket assembly100A to reduce processing time.

The two-piece design can provide the ability to inspect, for example, a weld that joins together the rear lateral rail94and the first side rail74.

Features of the disclosed examples include a bracket assembly that can help to avoid undesired exposure of components within a battery pack in response to a load, particularly a side load. The bracket can provide relatively accessible attachment and detachment locations.