Battery pack flow control system with fan arrangement

Abstract

Fan arrangement of a flow control system (58) comprising the following: a first fan (168d) that directs the flow under a first system operating condition through a first section (164d) of a battery pack enclosure (60) and under a second system operating condition through a second section (164e) of the battery pack enclosure (60), and a second fan (168e) that directs the flow below the first System operating condition is directed by the second section (164e), a third fan (168f) which directs the flow through a third section (164f) of a battery pack enclosure (60) under the first system operating condition and through the second section (164e) of the battery pack enclosure (60) under the second operating condition, wherein the first (164d) section and the third section (164f) are arranged on opposite sides of the second section (164e); and The lamellae (96) of a grid arrangement (94) can be aligned to a direction of flow through the battery sets (114) within the sections (164d-164f) in the first operating condition, and in the second operating condition some of the lamellae (96) can be actuated to guide the flow so that it moves between the second section (164e) and the first and third fans (168d, 168f).

Description

TECHNICAL FIELD

[0001] This disclosure relates generally to a system that controls flow through a battery pack, and more particularly to a system that includes an array of individual fans for controlling flow through sections of a battery pack. BACKGROUND

[0002] In general, electrified vehicles differ from conventional motor vehicles in that electrified vehicles are specifically powered using one or more electric motors supplied with energy by battery cells in a battery pack. 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] Referring to Fig. 1, an exemplary prior art battery pack 2 includes battery cells that power the electric motors of an electrified vehicle. A single fan 4 is connected to a duct 6. The fan 4 draws an airflow from the battery pack 2 through the duct 6. The airflow can cool the battery pack 2.

[0004] US 5,414,591 A discloses a magnetic disk storage system in which magnetic disk drives can be effectively cooled, and even if a blower device for one of the magnetic disk drives experiences problems or stops operating, a temperature rise of that magnetic disk drive can be suppressed to a minimum. To this end, in the magnetic disk storage system including a plurality of magnetic disk drives, blower devices are provided for each of the disk drives, and the disk drives are separated by partition walls in which openings are formed.

[0005] DE 603 ​​14 788 T2 shows a battery power supply device for supplying a high drive current required for large hybrid vehicles, a method for controlling the power supply device and a method for assigning an address. SUMMARY

[0006] According to the invention, a fan assembly according to claim 1 and a battery pack flow control system according to claim 8 are proposed. Advantageous embodiments are specified in the dependent claims and the following description.

[0007] In a further non-limiting embodiment of the foregoing fan assembly, the first fan directs the flow through the first section and the second section under the second system operating condition.

[0008] In a further non-limiting embodiment of any of the foregoing fan assemblies, a rotational axis of the first fan is aligned with a direction in which flow is directed through the first section, and a rotational axis of the second fan is aligned with a direction in which flow is directed through the second section.

[0009] In a further non-limiting embodiment of any of the foregoing fan assemblies, the first section is separated from the second section by a divider including at least one opening to allow flow between the first section and the second section.

[0010] In a further non-limiting embodiment of each of the aforementioned fan assemblies, a size of the at least one opening is adjustable to selectively increase or decrease the flow permitted through the at least one opening.

[0011] In a further non-limiting embodiment of any of the foregoing fan assemblies, the fans are configured to be mounted adjacent to an open area of ​​the battery pack enclosure, the open area permitting flow from the first section into the second section and further from the second section into the first section.

[0012] In a further non-limiting embodiment of any of the foregoing fan assemblies, the fan assembly includes a backflow preventer configured to block backflow through the second fan when the first fan directs flow through the second section.

[0013] In a further non-limiting embodiment of the aforementioned battery pack flow control system, the first fan is configured to direct flow through the first section and the second section when operated according to the second operating condition.

[0014] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, a rotational axis of the first fan is aligned with a direction in which flow is directed through the first section, and a rotational axis of the second fan is aligned with a direction in which flow is directed through the second section.

[0015] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the first section is separated from the second section by a divider including at least one opening to allow flow between the first section and the second section.

[0016] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the battery pack flow control system includes a backflow preventer configured to prevent backflow through the second fan when the first fan directs flow through the second section.

[0017] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the battery pack flow control system includes a first group of battery cells in the first section and a second group of battery cells in the second section.

[0018] In a further non-limiting embodiment of each of the foregoing battery pack flow control systems, the first and second groups of battery cells are configured to selectively supply energy to a powertrain of an electrified vehicle.

[0019] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the first and second groups of battery cells are spaced from the fan array to provide an open area in the enclosure.

[0020] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the flow in the open area may move from the first section to the second section and from the second section to the first section.

[0021] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the battery pack flow control system includes a grid assembly configured to control a direction of flow passage between the second portion and the fan array.

[0022] In a further non-limiting embodiment of any of the aforementioned battery pack flow control systems, the grid assembly is configured to move between a first position allowing a first flow rate between the second section and the second fan and a second position allowing a second flow rate between the second section and the second fan. The first flow rate is greater than the second flow rate.

[0023] In a further non-limiting embodiment of any of the foregoing battery pack flow control systems, the grid assembly in the second position directs more flow from the second section to the first section than the grid assembly in the first position. SHORT DESCRIPTION OF THE CHARACTERS

[0024] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The figures accompanying the detailed description may be briefly described as follows: Fig. 1 shows an exemplary battery pack of the prior art. Fig. 2 shows a powertrain of an exemplary electrified vehicle. Fig. Figure 3 shows a partial sectional view of a battery pack flow control system used to control the flow through a battery pack in the drive train of Fig. 2 battery pack used. Fig. Figure 4 shows a partial schematic cross-sectional view of selected parts of Fig. 3, when the battery pack flow control system is in a first operating condition. Fig. 5 shows the cross section of Fig. 4 when the battery pack flow control system is in a second operating condition. Fig. 6 shows a partial schematic cross-sectional view of another embodiment of a battery pack and a battery pack flow control system in a first operating condition. Fig. 7 shows the cross section of Fig. 6 in a second operating condition. Fig. Figure 8 shows steps of an example method for controlling the flow through the battery pack of Fig. 2 or Fig. 6 or another set of batteries. Fig. Figure 9 shows steps of an example method for controlling the flow through the battery pack of Fig. 2 or Fig. 6 or another set of batteries. DETAILED DESCRIPTION

[0025] This disclosure relates generally to directing flow through a battery pack, and more particularly to using fans of a fan array to influence the flow through different sections of the battery pack. The flow is a fluid, such as air, that can cool the battery pack. In another example, the flow can heat the battery pack.

[0026] Referring to Fig. 2, a powertrain 10 of a hybrid electric vehicle (HEV) includes a battery pack 14 that houses groups 18 of battery cells. In this example, each group 18 includes three individual battery cells.

[0027] 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 in the form of a combined motor-generator.

[0028] 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 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.

[0029] 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 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 member 32, a sun gear member 34, and a carrier assembly 36.

[0030] The generator 24 can be driven by the engine 20 through the power transmission unit 30 to convert kinetic energy into electrical energy. Alternatively, the generator 24 can also function as a motor to convert electrical energy into kinetic energy and thereby deliver torque to a shaft 38 connected to the power transmission unit 30.

[0031] 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 via a second power transfer unit 44. The second power transfer unit 44 may include a gear set with multiple wheels 46. Other power transfer units could be used in other examples.

[0032] The wheels 46 transmit torque from the engine 20 to a differential 48 to ultimately provide traction to the vehicle drive wheels 28. The differential 48 may include multiple wheels 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 the torque to the vehicle drive wheels 28.

[0033] 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, both the motor 22 and the generator 24 can each deliver electrical power to charge the cells of the battery pack 14.

[0034] With further reference to Fig. 2 now referring to Fig. 3, an exemplary power control system 58 for the battery pack 14 is connected to an enclosure 60 for the battery pack 14. The enclosure 60 is divided into sections 64a-64e or regions, represented by dashed lines.

[0035] Sections 64a-64e each comprise one of the battery cell groups 18a-18e. In this example, each section 64a-64e comprises three individual battery cells.

[0036] In another example, one or more of the sections 64a-64e may include a battery support device, such as an electronic battery control module (BECM), instead of or in addition to one of the groups 18a-18e of battery cells.

[0037] Sections 64a-64e are of similar size. In another example, sections 64a-64e could have different sizes to accommodate the battery support device, a number of battery cells other than three, or another component.

[0038] The example battery cells are prismatic cells, with terminals facing upward in battery pack 14. In another example, the battery cells are cylindrical. Other types of battery cells could also be used.

[0039] The exemplary enclosure 60 includes five sections 64a-64e, but could include a different number. In this example, no partition walls are used, and sections 64a-64e are not defined as structurally separate from each other. In another example, sections 64a-64e could be partially separated from each other by a separation structure, such as a wall, located within the enclosure 60. If a separation structure is used, the separation structure includes an engineered gap, such as an opening, that allows flow between sections 64a-64e when such flow is required.

[0040] The system 58 includes a fan assembly. In this example, the fan assembly includes a fan array 66 having a plurality of fans 68a-68e. The example fans 68a-68e are mounted directly to a sidewall 72 of the enclosure 60. The example fan array 66 includes five fans 68a-68e, but could also include a different number of fans.

[0041] The fan array 66 moves the flow through the battery pack 14. In this example, the flow in the enclosure 60 may move through spaces between the individual battery cells in the groups 18a-18e. The flow may also move through spaces between the groups 18a-18e and between the top of the groups and a top surface 74 of the enclosure 60.

[0042] Each of the five sections 64a-64e is connected to one of the five fans 68a-68e. In another example, more than one of the sections 64a-64e is connected to one of the fans 68a-68e. This means that the number of fans 68a-68e does not have to match the number of sections 64a-64e.

[0043] The fans 68a-68e are configured to draw the flow through at least one of the sections 64a-64e. The flow moves to the sections 64a-64e through an inlet provided by one or more apertures (not shown) in a sidewall 76 of the enclosure 60.

[0044] In another example, fans 68a-68e are configured to force flow through at least one of sections 64a-64e. In such an example, the passages could provide an outlet from the enclosure.

[0045] In yet another example, the fans 68a-68e are reversible and thus designed to selectively push or pull the flow through the sections 64a-64e.

[0046] The exemplary fans 68a-68e each include a bladed rotor that rotates about an axis A to move the flow. Axis A is shown in association with fan 68a, but it should be understood that each of the remaining fans 68b-68e has a corresponding axis of rotation. The exemplary fans 68a-68e are oriented such that axis A is aligned with a direction in which flow is directed through the groups 18a-18e in a corresponding one of the sections 64a-64e. Alternatively, the fans 68a-68e may each include an impeller that moves air perpendicular to axis A and approximately tangential to the impeller's rotation about axis A.

[0047] The groups 18a-18e terminate at laterally opposite sides 78. The fans 68a-68e are spaced from the lateral sides 78, providing an open area 80 between the fan array 66 and the groups 18a-18e of battery cells. In the open area 80, flow can move between the sections 64a-64e. If physical dividers are used to separate the sections 64a-64e, the physical dividers would not block all flow between the sections 64a-64e in the open area 80. For example, the physical dividers could include openings to allow flow between the sections 64a-64e within the open area 80. The open area 80 lies within the enclosure 60.

[0048] A sensor assembly 82a-82e is connected to each of the sections 64a-64e. The sensor assembly 82a-82e can be used to sense a temperature in one of the corresponding sections 64a-64e. The example sensor assemblies 82a-82e can sense a temperature of one or more associated battery cells or the temperature of an element conductively coupled to the associated battery cells, such as a busbar.

[0049] The flow through sections 64a-64e can change the temperatures of the battery cells and other components in sections 64a-64e. For example, increasing the flow through section 64a can reduce the temperature of section 64a and thus the temperatures sensed by sensor assembly 82a.

[0050] In general, a relatively uniform flow across battery cell groups 18a-18e can cool or heat the battery cells to a desired level. Under some conditions, deviations from a roughly uniform flow may be desirable.

[0051] With further reference to Fig. 3 now referring to the Fig. 4 and Fig. 5, each of the fans 68a-68e is operatively coupled to a controller 84. The fans 68a-68e can be individually adjusted by the controller 84 to selectively increase or decrease the flow through one or more of the sections 64a-64e relative to other sections 64a-64e. The groups 18a-18e are in the Fig. 4 and Fig. 5 shown schematically.

[0052] In this example, controller 84 adjusts the speeds of individual fans 68a-68e relative to each other to increase or decrease the flow through sections 64a-64e. Controller 84 may receive temperature readings from sensor assemblies 82a-82e and adjust the speeds in response to changes in the temperature readings. For example, if more flow is desired in section 64b than in section 64a, the speed of fan 68b may be increased relative to the speed of fan 68a. The effective speeds of individual fans 68a-68e may be controlled by adjusting the analog power flowing to fans 68a-68e, controlled by pulse-width modulation of the power or otherwise.

[0053] Although speeds are adjusted in this example, in other examples, controller 84 may make other adjustments to vary the flow through one or more of sections 64a-64e relative to other sections 64a-64e. For example, controller 84 could actuate an array of vanes to increase or decrease flow.

[0054] An operating condition for the system 58 may change to alter the flow through the sections 64a-64e. The operating condition may change, for example, in response to an increase in the temperatures of the battery cells in one or more of the sections 64a-64e of the battery pack 14 relative to the other battery cells of the battery pack 14. The sensor array 82a-82e connected to the sections 64a-64e may sense temperatures and provide temperature information to the controller 84, which then adjusts the fan array 66 to alter the flow through the sections 64a-64e.

[0055] A deviation in the temperatures of sections 64a-64e may be caused, at least in part, by an obstruction that prevents the flow from entering the enclosure 60. For example, the battery pack 14 is positioned behind a rear seat 88 of an electric vehicle. Seat belt anchors 90a, 90b, and 90c for the rear seat 88 may obstruct the flow to the openings 76 of the enclosure 60. In particular, the seat belt anchor 90b may prevent the flow from entering section 64b and section 64c.

[0056] The exemplary battery pack 14 extends transversely along the rear of the rear seat 88. The number and size of the battery cells within the battery pack 14 provide little or no space for a duct network on the lateral sides of the battery pack 14.

[0057] In this example, battery pack 14 is approximately 1,000 millimeters wide. Each of sections 64a-64e has a width of approximately 200 millimeters. The number of sections 64a-64e and the width of sections 64a-64e may vary from this example. The thickness of example battery cells may range from 12 to 25 millimeters for prismatic cells and from 5 to 13 millimeters for pouch cells. If battery cells of such a thickness are used, sections 18a-18e would likely each include more than three individual battery cells.

[0058] Each of the exemplary fans 68a-68e can produce approximately 34 m 3 / h through the associated section 64a-64e. In some examples, fans 64a-64e are similar in size to seat cooling fans. The number and size of sections 64a and 64e may be a function of a maximum flow required by battery pack 14 and the volumetric capacity of fans 68a-68e.

[0059] Due to the restricted flow, the temperatures of group 18b of battery cells in section 64b and group 18c of battery cells in section 64c may increase. To lower the temperature of the battery cells in sections 64b and 64c, controller 84 may increase the speed of fans 68b and 68c relative to the remaining fans 68a, 68d, and 68e. By increasing the speed of fans 68b and 68c, the flow through sections 64b and 64c is increased.

[0060] The operating condition may change in response to other information instead of or in addition to temperatures within sections 64a-64e. For example, the inoperability of one of the fans 68a-68e could trigger the change in the operating condition.

[0061] As an example, the system 58 of Fig. 4 is operated according to a first operating condition. In the first operating condition, fan 68a draws flow through section 64a, fan 68b draws flow through section 64b, fan 68c draws flow through section 64c, fan 68d draws flow through section 64d, and fan 68e draws flow through section 64e. In this example, the first operating condition corresponds to the situation in which each of fans 68a-68e is fully functional and capable of maintaining a desired flow through a corresponding one of sections 64a-64e.

[0062] In Fig. 5, the system 58 has changed to operate according to a second operating condition. In Fig. 5, the fan 68d is inoperative or cannot be operated at a level that can draw sufficient flow through section 64d. In response, the system 58 has transitioned to the second operating condition.

[0063] In the exemplary second operating condition, controller 84 has increased the speed of fans 68c and 68e relative to the other fans 68a and 68b. Operating fans 68c and 68e can compensate for the inability of fan 68d to draw sufficient flow through section 64d. The change in the speed of fans 68c and 68e represents the change from the first operating condition to the second operating condition in this example.

[0064] When the example system 58 is operated in the second operating condition, the fan 68c draws flow through the section 64c and through the adjacent section 64d. In addition, the fan 68e draws flow through the section 64e and the adjacent section 64d. By increasing the speed of the fans 68c and 68e, the flow moved by the fans 68c and 68e is increased, which helps the fan 68c and the fan 68e draw flow from the section 64d in addition to the sections 64c and 64e. The open area 80 provides a technical opening or gap between the adjacent sections 64a-64e to allow flow to be moved from one of the sections 64a-64e to another of the sections 64a-64e.

[0065] In some examples, fans 68a-68e may each include a backflow preventer 92, which is schematically illustrated in connection with fan 68d. Backflow preventer 92 may allow flow in one direction through fan 68, but block backflow through fan 68d in a second, opposite direction.

[0066] When the system 58 is in the first operating condition, the non-return valve 92 is in the first position of Fig. 4 to allow flow to leave the enclosure 60 through the fan 68d. When the system 58 is in the second operating condition, the non-return valve 92 is in the second position of Fig. 5 to prevent flow through the fan 68d from entering the open area 80.

[0067] The direction of the flow may cause the backflow preventer 92 to move between the first position and the second position. For example, the backflow preventer 92 may include flaps that open when the flow moves from the open area 80 to the fan 68d and close when the flow moves from outside the enclosure 60 to the fan 68d.

[0068] In some examples, the controller 84 actuates the non-return valve 92 and maintains it in the first position or the second position. This allows the non-return valve 92 to be used to change the system 58 between the first and second operating conditions. The non-return valve 92 may be used instead of, or in addition to, increasing the speed of the fan 68c and the fan 68e relative to the speed of the fans 68a and 68b.

[0069] In the examples where the sections are separated by physical dividers, each including one or more openings to selectively permit flow between sections 64a-64e in the open area, the size of the one or more openings is adjustable. For example, controller 84 could actuate fins or a similar structure to selectively increase or decrease the effective opening size. By increasing the size of the opening, more flow can flow from one of sections 64a-64e through the opening to an adjacent section. By decreasing the size of the opening, less flow can flow from one of sections 64a-64e through the opening to an adjacent section.

[0070] Now referring to the Fig. 6 and Fig. 7, another exemplary system 158 for controlling flow through a battery pack 114 includes six sections 164a-164f, each housing a corresponding group 118a-118f of battery cells. Each of the sections 164a-164f includes a corresponding group 118a-118f of battery cells. The groups 118a-118f are illustrated schematically.

[0071] The battery cells in groups 118a-118f terminate at a laterally opposite side, represented by line 178. Each of sections 164a-164f is connected to a corresponding fan 168a-168f. An open area 180 is positioned between the laterally opposite side and fans 168a-168f.

[0072] The battery pack 114 includes a grid assembly 94 positioned between the groups 118a-118f and the fans 168. The grid assembly 94 is operatively connected to a controller 184, which is also operatively connected to the fans 168a-168f.

[0073] The grid assembly 94 includes a plurality of vanes 96. The controller 184 can selectively actuate individual vanes 96 of the grid assembly 94 to alter the flow through the sections 164a-164f of the battery pack 114. One of ordinary skill in the art, having the benefit of this disclosure, will understand how to actuate selected vanes of the grid assembly 94.

[0074] In Fig. 6, the fins 96 of the grid assembly 94 are aligned with a direction of flow through the battery packs within the sections 164a-164f. This positioning of the fins 96 facilitates the flow between the sections 164a-164f and the associated fans 168a-168f. Fig. 6, the positioning of the slats 96 is representative of the exemplary system 158 operated in a first operating condition.

[0075] In Fig. 7, some of the louvers 96 were actuated to guide the flow so that it moves between the section 164e and the fans 168d and 168f and not between the section 164e and the fan 168e. The louvers 96 can be adjusted to the position of Fig. 7 when the fan 168e is unable to move sufficient air flow through the section 164e. The positioning of the louvers 96 of Fig. 7 is representative of the exemplary system 158 operating in a second operating condition.

[0076] Referring to Fig. 8, an exemplary method 200 controls the flow through a battery pack that is the battery pack 14 of the Fig. 3-5, the battery pack 114 of the Fig. 6 and Fig. 7 or another battery pack. The steps of method 300 may be performed on processing circuitry of a controller operatively connected to temperature sensors, a fan array, and other parts of the battery pack.

[0077] The method 200 operates in a first operating condition at step 210. At step 210, the method 200 moves the flow through a first portion of a battery pack enclosure using a first fan and moves the flow through a second portion of the battery pack enclosure using a second fan.

[0078] The method 200 proceeds to a step 220 when operating according to a second operating condition. In step 220, the method 200 moves the flow through the second section using the first fan.

[0079] One or more factors may cause the method 200 to transition from the first operating condition of step 210 to the second operating condition of step 220.

[0080] In one example, the inoperability of the second fan may cause the method 200 to proceed from step 210 to step 210.

[0081] In another example, the second fan is functional, but the method 200 proceeds from step 210 to step 220 because the second fan is unable to move sufficient flow through the second section.

[0082] In still further examples, method 200 transitions from step 210 to step 220 in response to a change in temperatures. For example, a controller operatively connected to temperature sensors associated with the second section may compare the actual temperature of the second section to an expected temperature of the second section. If the actual temperature differs from the expected temperature, method 200 transitions from step 210 to step 220. The deviation required to prompt the transition from step 210 to step 220 may be a deviation that exceeds a threshold, such as two degrees Celsius. The actual temperature reading may be an actual temperature reading of a temperature of battery cells within the second section of the battery pack enclosure.

[0083] The expected temperature reading may be an expected temperature reading for battery cells within the second section. Instead, the expected temperature reading may be an average temperature of the battery pack, such as an average temperature of all battery cells within the battery pack enclosure.

[0084] At step 220, method 200 may adjust the first fan to cause the first fan to move the flow through the second section. An example adjustment may be increasing a speed of the first fan to increase the flow moved by the first fan. By increasing the flow moved by the first fan, the first fan is assisted in moving the flow through the first and second sections.

[0085] In some examples, method 200 may adjust the first fan at step 220 based on a flow model. For example, a database stored in a memory portion of the controller may provide the flow model.

[0086] The database can include a table of flow rates associated with different fan speeds, as well as estimates of the flow required to reduce temperature differences. The flow required to reduce temperatures can be affected by several factors, such as ambient temperatures, humidity, etc. These factors can be stored in the table and affect the flow required to reduce temperatures by a desired amount.

[0087] If the method 200 is at step 220 and the temperature of the second section is, for example, two degrees Celsius higher than a desired temperature, the method 200 references the flow model to determine a new target speed for the first fan. When the first fan operates at the new target speed, the first fan moves enough flow through the second section to reduce the temperature by two degrees Celsius.

[0088] Now referring to Fig. 9, another method 300 for controlling flow through a battery pack begins at a step 310. The method 300 may be used in conjunction with the battery pack 14 of the Fig. 3-5, the battery pack 114 of the Fig. 6 and Fig. 7 or another battery pack. The steps of method 300 may be performed on processing circuits of a controller operatively connected to temperature sensors, a fan array, and other parts of the battery pack.

[0089] After starting at step 310, method 300 proceeds to step 320. Step 320 essentially compares temperature data for various sections of the battery pack enclosure. The temperature data is, for example, battery cell temperature data.

[0090] In some examples, step 320 calculates whether a temperature change rate in one portion of the battery pack enclosure deviates from an average temperature of the other portions of the battery pack enclosure. In another example, step 320 calculates whether a temperature change rate in one portion of the battery pack deviates from an average temperature of all portions of the battery pack enclosure.

[0091] The method then proceeds to a step 330, which calculates to determine whether a temperature change rate in a section of the battery pack enclosure deviates from an expected temperature change rate for that section. An expected temperature change rate for a section of the battery pack enclosure could be based on several variables, including a thermal model of battery heat generation / dissipation, flow provided by fans, the root mean square of the battery cell current, battery cell mass, temperatures, etc. With respect to the root mean square of the battery cell current, squaring the battery cell current changes negative battery cell current values ​​to positive ones.

[0092] Therefore, the current flowing into and out of the battery is added to the root mean square current. Both charging and discharging can generate thermal energy.

[0093] The method 300 then proceeds to step 340, which relates to the calculations of step 320 and step 330. If, based on the calculations of step 320 and step 330, a temperature of a portion of the battery pack enclosure does not deviate, the method 300 returns to start 310. If, based on the calculations of step 320 and step 330, the temperature of a portion of the battery pack enclosure deviates, the method proceeds to step 350. Going to step 350 from step 340 may be based on a deviation calculated in step 320, a deviation calculated in step 330, or both.

[0094] At step 350, method 300 calculates a flow increase required by one or more fans adjacent to the section of the battery pack where the temperature deviation occurs. The required flow increase may be calculated using a flow model that includes fan flow. The flow increase corresponds to the flow increase required to adjust the thermal energy in the section so that a temperature deviation no longer occurs in the section.

[0095] The method 300 then proceeds to a step 360, where the method 300 calculates whether at least one area, such as a center, of a battery cell in the temperature-deviated section is predicted to exceed desired temperatures due to thermal inertia. For example, the temperature sensor may measure the outside of the battery cell, but the critical temperature in the center of the battery may be warmer and take longer to respond to airflow changes.

[0096] The prediction at step 360 may be based on a thermal model of battery cell temperatures based on temperature rise rate, temperatures, battery heat generation / dissipation, and battery thermal properties. Example thermal properties may include battery mass, density, size, shape, thermal conductivity, connectivity, emissivity, and other factors well known in the field of thermal analysis, etc. The prediction may be a prediction associated with a specific region of a battery cell within the section, such as a central region of the battery cell.

[0097] If at step 360 the battery cell is not predicted to exceed desired temperatures due to thermal inertia, the method 300 proceeds to a step 370 where a duty cycle of the adjacent fan(s) is increased to provide the flow increase calculated in step 340 to the portion where the temperature deviation occurs.

[0098] If at step 360 it is predicted that the battery cell will exceed desired temperatures due to thermal inertia, the method 300 proceeds to a step 380 where an additional flow increase is requested from the adjacent fan(s) in addition to the flow increase calculated in step 340.

[0099] The method 300 then proceeds from step 380 to step 370 where the duty cycle of the adjacent fan(s) is increased to provide the flow increase calculated in step 340 and the additional flow increase calculated in step 380.

[0100] When going from step 380 to step 370, the flow in step 370 includes the flow increase calculated in step 340 and the additional flow increase calculated in step 380. When going from step 360 to step 370, the flow in step 370 includes the flow increase calculated in step 340.

[0101] The method 300 ends at a step 390 after the step 370.

[0102] An exemplary system utilizing method 300 monitors temperatures of sections of a battery pack enclosure, and in particular, battery cell temperatures. Method 300 utilizes a thermal model and monitored temperatures to detect temperature increases within an individual section. The temperature increases may be caused, for example, by a malfunctioning fan.

[0103] Method 300 then uses a flow model to determine the amount of flow increase required by one or more adjacent fans to move thermal energy away from the section experiencing the temperature increase. This facilitates maintaining a relatively consistent temperature throughout all sections of the battery pack enclosure and can prevent temperatures from rising to undesirable levels due to thermal inertia.

[0104] It is understood that the outermost sections of the battery pack enclosure may be adjacent to a single fan, rather than being positioned directly between two fans. For example, section 64e in Fig. 4 is aligned with fan 68e and adjacent to fan 68d. Section 64d in Fig. 4 is aligned with fan 68d and adjacent to fans 68c and 68e.

[0105] If the temperature deviation occurs in an outermost section, the flow increase of the directly adjacent fan may involve doubling the flow moved by the adjacent fan.

[0106] Features of some of the disclosed embodiments include a fan array for moving flow through groups of battery cells. The fan array is part of a system that is reduced in size compared to prior art systems. The system of the present disclosure may have a reduced flow path length, resulting in lower pressure drop and reduced noise, vibration, and harshness. The system of the present disclosure may reduce ductwork requirements compared to prior art designs, as well as potential leak points for flow. Furthermore, the fan array may compensate for the inability of one or more of its fans to move sufficient flow.

[0107] The foregoing description is exemplary and not restrictive. Variations and modifications to the disclosed examples may be apparent to those skilled in the art without necessarily departing from the spirit of this disclosure. Therefore, the scope of this disclosure can only be determined by reference to the following claims.

Claims

[1] Fan assembly of a flow control system (58) comprising: a first fan (168d) which directs the flow under a first system operating condition through a first portion (164d) of a battery pack enclosure (60) and under a second system operating condition through a second portion (164e) of the battery pack enclosure (60), and a second fan (168e) which directs the flow under the first System operating condition through the second section (164e), a third fan (168f) directing the flow through a third section (164f) of a battery pack enclosure (60) under the first system operating condition and through the second section (164e) of the battery pack enclosure (60) under the second operating condition, the first (164d) section and the third section (164f) being disposed on opposite sides of the second section (164e); and Slats (96) of a grid arrangement (94) are alignable with a direction of flow through the battery packs (114) within the sections (164d-164f) in the first operating condition, and in the second operating condition, some of the slats (96) are operable to guide the flow so that it moves between the second section (164e) and the first and third fans (168d, 168f). [2] The fan assembly of a flow control system (58) of claim 1, wherein the first fan (168d) directs flow through the first section (164d) and the second section (164e) under the second system operating condition. [3] The fan assembly of a flow control system (58) of claim 1, wherein a rotational axis of the first fan (168d) is aligned with a direction in which the flow is directed through the first portion (164d) and a rotational axis of the second fan (168e) is aligned with a direction in which the flow is directed through the second portion (164e). [4] The fan assembly of a flow control system (58) of claim 1, wherein the first portion (164d) is separated from the second portion (164e) by a divider including at least one opening to allow flow between the first portion (164d) and the second portion (164e). [5] A fan assembly of a flow control system (58) according to claim 4, wherein a size of the at least one opening is adjustable to selectively increase or decrease the flow allowed through the at least one opening. [6] The fan assembly of a flow control system (58) of claim 1, wherein the fans are configured to be mounted adjacent to an open area of ​​the battery pack enclosure (60), the open area permitting flow from the first section (164d) into the second section (164e) and further from the second section (164e) into the first section (164d). [7] The fan assembly of a flow control system (58) of claim 1, further comprising a backflow preventer (92) configured to prevent backflow through the second fan (168e) when the first fan (168d) directs flow through the second section (164e). [8] Battery pack flow control system comprising: an enclosure having a first section (164d) and a second section (164e); a first group of battery cells in the first section (164d) and a second group of battery cells in the second section (164e); and a fan array (66) having a first fan (168d) and a second fan (168e), wherein the first fan (168d) is configured to direct the flow through the first section (164d) when operated according to a first operating condition and to direct the flow through the second section (164e) when operated according to a second operating condition, and the second fan (168e) is configured to direct the flow through the second section (164e) when operated according to the first operating condition; and Slats (96) of a grid arrangement (94) are alignable with a direction of flow through the battery packs (114) within the sections (164d-164e) in the first operating condition, and in the second operating condition, some of the slats (96) are operable to guide the flow so that it moves between the second section (164e) and the first and a third fan (168d, 168f). [9] The battery pack flow control system of claim 8, wherein the first fan (168d) is configured to direct flow through the first portion (164d) and the second portion (164e) when operated according to the second operating condition. [10] The battery pack flow control system of claim 8, wherein a rotational axis of the first fan (168d) is aligned with a direction in which the flow is directed through the first section (164d) and a rotational axis of the second fan (168e) is aligned with a direction in which the flow is directed through the second section (164e). [11] The battery pack flow control system of claim 8, wherein the first portion (164d) is separated from the second portion (164e) by a divider including at least one opening to allow flow between the first portion (164d) and the second portion (164e). [12] The battery pack flow control system of claim 8, further comprising a backflow preventer (92) configured to block flow through the second fan (168e) when the first fan (168d) directs flow through the second section (164e). [13] The battery pack flow control system of claim 8, wherein the first and second groups of battery cells (18) are configured to selectively supply energy to a powertrain (10) of an electrified vehicle. [14] The battery pack flow control system of claim 8, wherein the first and second groups of battery cells (18) are spaced from the fan array (66) to provide an open area in the enclosure. [15] The battery pack flow control system of claim 14, wherein the flow in the open area can move from the first section (164d) to the second section (164e) and from the second section (164e) to the first section (164d). [16] The battery pack flow control system of claim 8, further comprising a grid assembly configured to control a direction of flow passage between the second portion (164e) and the fan array (66). [17] The battery pack flow control system of claim 16, wherein the grid assembly is configured to move between a first position allowing a first flow rate between the second portion (164e) and the second fan (168e) and a second position allowing a second flow rate between the second portion (164e) and the second fan (168e), the first flow rate being greater than the second flow rate. [18] The battery pack flow control system of claim 17, wherein the grid assembly in the second position directs more flow from the second section (164e) to the first section (164d) than the grid assembly in the first position.

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