Patent ID: 12230775

DETAILED DESCRIPTION

In the following description, numerous specific details are outlined to provide a thorough understanding of the presented concepts. The presented concepts may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the described concepts. While some concepts will be described in conjunction with the specific embodiments, it will be understood that these embodiments are not intended to be limiting.

Battery Module Examples

FIG.1Ais a schematic perspective view of battery module100, in accordance with some examples. Specifically, battery module100comprises enclosure110formed by a first set of side walls130and a second set of side walls140as well as first cover171and second cover172. The entire enclosure110can be formed from aluminum. Referring toFIGS.1B,1C, and1D, enclosure110comprises a first enclosure portion115and a second enclosure portion116, separated by a thermal portion120. Specifically, the first enclosure portion115is defined by the first set of side walls130. The first enclosure portion115is used to enclose a first set of battery cells151(e.g., shown inFIG.2A) and can be sealed with the first cover171. The second enclosure portion116is defined by the second set of side walls140. The second enclosure portion116is used to enclose a second set of battery cells152and can be sealed with the first cover172. The first set of battery cells151and the second set of battery cells152are collectively referred to as battery cells150. As shown inFIGS.1A-1D, first set of battery cells151and/or second set of battery cells152can include cylindrical battery cells (e.g., 18650 cells, 21700 cells, 30700 cells, 4680 cells). However, other types of battery cells are within the scope.

Referring toFIGS.1B,1C, and1D, thermal portion120is positioned between first enclosure portion115and second enclosure portion116and comprises first thermal wall121and second thermal wall122as well as thermal cavity180. Specifically, the first thermal wall121separates the thermal cavity180from the first enclosure portion115, while the second thermal wall122separates the thermal cavity180from the second enclosure portion116. The first thermal wall121provides a thermal pathway from the first set of battery cells151to the cooling liquid within the thermal cavity180. Similarly, the second thermal wall122provides a thermal pathway from the second set of battery cells152to the cooling liquid within the thermal cavity180. Overall, the first set of battery cells151is positioned within the first enclosure portion115, surrounded by the first set of side walls130, and thermally coupled to the first thermal wall121. The second set of battery cells152is positioned within the second enclosure portion116, surrounded by the second set of side walls140, and thermally coupled to the second thermal wall122.

The X-Y boundary of thermal portion120is defined by the first set of side walls130and the second set of side walls140(along the Z-axis). In other words, the first set of side walls130and the second set of side walls140are parts of the first enclosure portion115, the second enclosure portion116, and the thermal cavity180. The first set of side walls130and the second set of side walls140are joined at thermal cavity180(shown as a “wall interface” inFIG.1A). Overall, thermal cavity180is formed by the first thermal wall121, the second thermal wall122, the first set of side walls130, and the second set of side walls140.

In some examples, the entire enclosure110is a monolithically cast component. In other words, there are no joining seams (e.g., weld seams) and joining structures (e.g., brackets) between different components of enclosure110, such as between the first thermal wall121, the second thermal wall122, the first set of side walls130, and the second set of side walls140. In other words, the first thermal wall121, the second thermal wall122, the first set of side walls130, and the second set of side walls140are all formed in the same casting operation forming one monolithically cast component comprising these elements. The thermal cavity180is also formed/defined during this operation. Forming the enclosure110as a single monolithically cast component helps to simplify the fabrication process (e.g., by reducing the number of operations), reduce the total weight of the enclosure110, and improve the structural integrity of the enclosure110.

Alternatively, at least the first thermal wall121can be friction-stir welded to the first set of side walls130as further described below with reference toFIG.2D. The second thermal wall122, the first set of side walls130, and the second set of side walls140can still all be formed in the same metal casting operation thereby forming one monolithically cast component comprising these elements. At this point, the thermal cavity180is not yet formed/defined since the first thermal wall121is not present. The first thermal wall121can be formed in a separate casting operation and later friction-stir welded to the first set of side walls130. This example casting-welding sequence allows simplifying the metal casting process of various features inside the battery cells150.

Referring toFIG.1C, in some examples, the exterior surfaces of the first set of side walls130and the second set of side walls140form an angle that is less than 180° or, more specifically, less than 176° or even less than 174° around the perimeter of enclosure110. The corner defined by this angle is the interface between the first set of side walls130and the second set of side walls140, which can coincide with a middle plane through the thermal portion120/the thermal cavity180. As such, the exterior surfaces of the first set of side walls130and the second set of side walls140do not extend along a straight line (shown with a dotted line inFIG.1C).

This exterior-surface angle also corresponds to an interior-surface angle (α) as shown inFIG.1D. For example, the interior surfaces of the first set of side walls130and the second set of side walls140form an interior-surface angle (α) that is greater than 180° or, more specifically, greater than 182° or even greater than 184° around the perimeter of enclosure110. It should be noted that this interior-surface angle (α) also corresponds to an angle (β) between the interior surface of the first set of side walls130and the first thermal wall121(or between the interior surface of the second set of side walls140and the second thermal wall122), which can be greater than 90° or, more specifically, greater than 92° or even greater than 94°. For example, these interior-surfaces-to-thermal-walls angles (β) can be 91°-97° or, more specifically, 93°-95°.

These angles correspond to the first set of side walls130forming a tapered-shaped first enclosure portion115over the first thermal wall121. Similarly, the second set of side walls140forms a tapered-shaped second enclosure portion116over the second thermal wall122. As such, the opening of the first enclosure portion115can be larger than the portion of the first thermal wall121(at the bottom of the first enclosure portion115) thereby enabling additional access to the first set of battery cells151(proximate to this opening) to install/interconnect the battery cells. Similarly, the opening of the second enclosure portion116can be larger than the portion of the second thermal wall122(at the bottom of the second enclosure portion116) thereby enabling additional access to the second set of battery cells152(proximate to this opening) to install/interconnect the battery cells. This access can also be used, e.g., for mounting a first interconnecting assembly161and a second interconnecting assembly162.

Referring toFIG.1C, in some examples, the first set of side walls130has a height (in the Z-direction) greater than the height of the first set of battery cells151. This approach allows the use of the first set of side walls130for mounting additional components without interfering with the first set of battery cells151. With reference toFIGS.1C and1D, in some examples, the first set of side walls130comprises a top edge131and an intermediate edge132, each extending parallel to the first thermal wall121. The intermediate edge132is positioned between the top edge131and the first thermal wall121and can be used to support the first interconnecting assembly161. As shown inFIG.1C, the intermediate edge132can be positioned closer to the first thermal wall121than the plane defined by battery cell contacts. The first interconnecting assembly161may comprise protrusion extending from the battery-cell-contact plane and engaging the intermediate edge132of the first set of side walls130.

Referring toFIG.1C, in further examples, the battery module100further comprises a first cover171and a second cover172. The first cover171is supported on the top edge131of the first set of side walls130and protects the first interconnecting assembly161. The second cover172is supported on the second set of side walls140, e.g., using a similar edge, and protects the second interconnecting assembly162.

Referring toFIGS.1C and1D, in some examples, battery module100comprises a first enclosure divider135and a second enclosure divider145, which are optional components. For example, a portion of the first enclosure portion115between the first enclosure divider135and the top edge131(or, more specifically, the first cover171when the first cover171is installed) is filled with fire-retardant foam139(e.g., a silicone foam having a fire-retardant filler particle). In some examples, the distance between the first enclosure divider135and the top edge131is 10-40 millimeters or, more specifically, 15-30 millimeters. Similarly, a portion of the second enclosure portion116between the second enclosure divider145and the top edge of the second set of side walls140(or the second cover172) is filled with fire-retardant foam139. The first enclosure divider135and second enclosure divider145reduce the amount of fire-retardant foam139needed in each battery module100thereby reducing the cost and weight of the battery module100. It should be noted that the fire-retardant foam139protects the most critical part of battery cells150, e.g., the cell caps comprising cell terminals, and wire bonding connections to these cells.

As noted above, in some examples, battery module100comprises a first interconnecting assembly161, surrounded and supported by the first set of side walls130and interconnecting the first set of battery cells151. Specifically, the first interconnecting assembly161is positioned between the first set of battery cells151and the first cover171. The first cover171protects the first interconnecting assembly161. In more specific examples, the battery module100also comprises the second interconnecting assembly162, surrounded and supported by the second set of side walls140and the interconnecting second set of battery cells152.

FIG.1Eis another example of interconnecting assemblies that extend outside of their respective enclosure portions.FIG.1Fis a schematic perspective view of the two interconnecting assemblies inFIG.1Ewithout the module enclosure and battery cells. Specifically, a portion of the first interconnecting assembly161is positioned within the first enclosure portion115together with the first set of battery cells151. This portion of the first interconnecting assembly161comprises bus bars163, which are wire-bonded to the cell terminals. Another portion of the first interconnecting assembly161extends outside the first enclosure portion115and extends over the external surface of one long side wall of the first set of side walls130.FIG.1Ealso illustrates a similar portion of the second interconnecting assembly162extending outside the second enclosure portion116and over the external surface of one long side wall of the second set of side walls140.

This external portion of the first interconnecting assembly161may be in the form of a printed circuit board164(or multiple printed circuit boards (PCBs) as shown inFIGS.1E and1F) and may be connected to bus bars163using wire bonds165. These printed circuit boards164can be bonded to the external surface of the first set of side walls130and the second set of side walls140using a pressure-sensitive adhesive (PSA). The PSA eliminates the need for the fastener. For example, the wire-bonding process can distort the printed circuit board164or at least shift this position, while the PSA can help to provide more uniform support (across the entire plane rather than point supports available with fasteners. It should be noted that a PCB can be quite flexible in the out-of-plane direction, and such uniform support can be essential to preserve all connections.

When multiple printed circuit boards164are used, these multiple printed circuit boards164can be interconnected through a common bus bar167and/or PCB links168. Printed circuit boards164can be used to perform various functions of the battery management system at the module level. Additional battery management systems can be provided at the battery pack and/or vehicle levels. For example, printed circuit boards164are used for individual voltage measurements at each bus bar163.

Referring toFIG.2B, in some examples, each of the first set of side walls130and the second set of side walls140comprises side wall openings119for protruding bus bars to each of the first interconnecting assembly161and the second interconnecting assembly162. A pair of side wall openings119can be used to provide access to the first interconnecting assembly161positioned in the first enclosure portion115. These side wall openings119may be positioned on the opposite (smaller) sides of the first set of side walls130. Another pair of side wall openings119can be used to provide access to the second interconnecting assembly162positioned in the second enclosure portion116. These side wall openings119may be positioned on the opposite (smaller) sides of the second set of side walls140. In some examples, side wall openings119are not enclosed openings (e.g., as shown inFIG.2B) but instead are slot openings extending to the top edge131of the first set of side walls130(and a similar edge of the second set of side walls140). The slot openings simplify the installation of bus bars for interconnecting this battery module100with other modules in a battery pack. In some examples, the bus bars are parts of the first interconnecting assembly161and/or the second interconnecting assembly162.

Referring toFIG.2B, in some examples, enclosure110further comprises a first support bracket175and a second support bracket176positioned on opposite sides of enclosure110. The first support bracket175and the second support bracket176extend across and are monolithic with both the first set of side walls130and the second set of side walls140. The first support bracket175and the second support bracket176are used to support module100within a battery pack, e.g., as schematically shown inFIG.6B.

Referring toFIG.1D, in some examples, the first thermal wall121comprises an electrically insulating surface layer125, forming the bottom of the first enclosure portion115and directly interfacing with the first set of battery cells151(when these cells are positioned within the first enclosure portion115as shown inFIG.1C). For example, the base of the first thermal wall121can be formed from aluminum, while electrically insulating surface layer125can be formed using polymer, plastic, or other suitable material. The thickness of the layer may be minimal to ensure electrical isolation while minimizing the heat flux resistance between the first set of battery cells151and the cooling liquid within the thermal cavity180. The second thermal wall122may comprise a similar electrically insulating surface layer125, forming the bottom of the second enclosure portion116and directly interfacing with the second set of battery cells152. In some examples, the electrically insulating surface layer125is formed by thermally conductive epoxy, which also bonds and supports the battery cells150relative to the corresponding thermal wall.

Referring toFIGS.2B-2C, in some examples, the enclosure is formed as a single-cast monolithic component such that the thermal portion120comprises at least two post-cast plugs129positioned on opposite sides of enclosure110. These post-cast plugs129are used to seal openings that are left from supporting rods protruding to a dissolvable core, which are used to form the thermal cavity180while metal casting the enclosure110. The post-cast plugs129can be parts of the side walls and/or parts of the first thermal wall121, e.g., as shown inFIG.2B(and parts of the second thermal wall122, which is not visible inFIG.2B). Referring toFIG.2C, in some examples, post-cast plugs129are only parts of the side walls, but not of the first thermal wall121or the second thermal wall122. The first thermal wall121and the second thermal wall122can be free from any plugs (e.g., can be a continuous monolithic structure). In these examples, wherein post-cast plugs129are only parts of the side walls, post-cast plugs129can have an elongated shape (e.g., as shown inFIG.2C). This shape is determined by the structures used to support a dissolvable core. When present, post-cast plugs129can be welded (e.g., friction-stir welded) into respective components of the enclosure110.

Referring toFIG.2D, in some examples, enclosure110does not have any post-cast plugs129. Instead of using a dissolvable core, enclosure110is cast without the first thermal wall121(which can be cast separately). The first thermal wall121is then welded (e.g., friction-stir welded) to the first set of side walls130, e.g., forming a friction-stir weld128.

Referring toFIGS.2B-2D, in some examples, thermal portion120further comprises a first fluid port181and a second fluid port182providing fluidic communication to the thermal cavity180. For example, the first fluid port181can be operable as an inlet port for a thermal fluid to enter thermal cavity180, while the second fluid port182can be operable as an outlet for thermal fluid to exit thermal cavity180. In more specific examples, the second fluid port182is positioned closer to the top edge131of the first set of side walls130than the first fluid port181thereby reducing the trapping of bubbles inside thermal cavity180when filling thermal cavity180with the thermal fluid.

Referring toFIGS.3A-3C, in some examples, thermal portion120comprises a divider183extending through thermal cavity180between the first thermal wall121and the second thermal wall122. The divider183is monolithic with the second thermal wall122and, in some examples (e.g., described above with reference toFIGS.2B and2C) with the first thermal wall121. Alternatively, the first thermal wall121may contact, may be sealed against, or maybe even welded to the first thermal wall121(e.g., when the first thermal wall121is not a part of the remaining enclosure casting).

Referring toFIGS.3A-3C, divider183at least partially separates thermal cavity180into the first cavity portion184and a second cavity portion185. The first fluid port181extends into the first cavity portion184, while the second fluid port182extends into the first cavity portion185. Specifically, the first fluid port181and second fluid port182are positioned on the same side of the enclosure (i.e., first enclosure side111). Specifically, enclosure110comprises a first enclosure side111and a second enclosure side112. The divider183extends to the first enclosure side111and is separated by a gap from the second enclosure side112thereby providing a fluid path between the first cavity portion184and the second cavity portion185within the thermal cavity180. A combination of the divider183and the gap allows the positioning of both fluid ports on the same side while circulating the thermal fluid through the entire thermal cavity180. In some examples, the first thermal wall121and/or the second thermal wall122comprise flow redirectors187to direct the flow from the first cavity portion184to the second cavity portion185through the gap. Specifically, the thermal fluid flows in the direction of the X-axis in the first cavity portion184from the first enclosure side111to the second enclosure side112. The flow redirectors187then redirect the fluid in the direction of the Y-axis and through the gap. The flow redirectors187then again redirect the fluid in the direction opposite of the X-axis when the fluid enters the second cavity portion185. Finally, the thermal fluid flows through the second cavity portion185from the second enclosure side112to the first enclosure side111.

In some examples, when enclosure110is a monolithically cast component, enclosure110may initially (right after the casting) have a divider183that extends between the first enclosure side111and the second enclosure side112, e.g., as schematically shown inFIG.4A. In other words, at this stage, the first cavity portion184and the second cavity portion185are fluidically isolated from each other. This approach relies on two dissolvable cores when casting enclosure110thereby simplifying the casting process. One of these cores forms the first cavity portion184, while the other core forms the second cavity portion185.

The fluidic communication between the first cavity portion184and the second cavity portion185is provided by drilling out a portion of divider183to form a gap between the divider183and the second enclosure side112. A side plug113may be then installed into the opening in the second enclosure side112, formed during this drilling, e.g., as schematically shown inFIG.4B. As such, in some examples, the second enclosure side112has a side plug113coaxial with the divider183.

Referring toFIGS.3A-C, in some examples, the thermal portion120comprises a set of pins186extending through the thermal cavity180between the first thermal wall121and the second thermal wall122. In some examples, these pins186are monolithic with the second thermal wall122. In more specific examples, these pins186are also monolithic with the first thermal wall121. Alternatively, these pins186may extend and even contact the first thermal wall121but not join the first thermal wall121. These pins186can help to intermix/create some turbulence with the thermal fluid and to transfer heat between this thermal fluid (provided in the thermal cavity180) and the battery cells150during the operation of battery module100. Specifically, all these pins186increase the contact surface with the thermal fluid. Referring toFIG.3C, in some examples, pins186has a non-uniform spatial density within thermal cavity180determined by the temperature, expected in each battery of the first set of battery cells151and the second set of battery cells152. For example, the concentration of pins186can be proportional to the current through the battery cells150positioned in the same projection.

Examples of Fabricating Battery Modules

FIG.5is a process flowchart corresponding to method500of fabricating a battery module100, in accordance with some examples. Various examples of battery module100are described above with reference toFIGS.1A-3C.

In some examples, method500comprises (block510) die casting an enclosure110a first set of side walls130, a second set of side walls140, and a second thermal wall122. In some examples, this die-casting operation also forms a first thermal wall121. For example, a casting tool may have one or more dissolvable cores to form a thermal cavity180. These cores are removed (after the casting) to free up the thermal cavity180. When multiple dissolvable cores are used, different portions of the thermal cavity180may be interconnected as described above with reference toFIGS.4A and4B.

Alternatively, the first thermal wall121is not formed as a part of this die-casting operation (block510). Instead, the first thermal wall121is formed in a separate operation and later attached to the first set of side walls130. For example, method500may comprise (block515) friction-stir welding the first thermal wall121to the first set of side walls130thereby forming the thermal cavity180during this welding operation.

In some examples, method500comprises forming insulating surface layers125on the external surfaces of the first thermal wall121and the second thermal wall122. For example, plastic sheets may be positioned over these walls. Alternatively, insulating surface layers125may be provided in the form of a thermally-conductive epoxy and used to bond the battery cells150to their respective thermal walls.

Method500may proceed with (block520) positioning a first set of battery cells151into the enclosure110or, more specifically, into the first enclosure portion115. After this operation, the first set of battery cells151is surrounded by the first set of side walls130, which protrude above the first set of battery cells151. Furthermore, the first set of battery cells151is thermally coupled to the first thermal wall121.

Method500may also comprise (block530) positioning a second set of battery cells152into enclosure110or, more specifically, into the second enclosure portion116. After this operation, the second set of battery cells152is surrounded by the second set of side walls140and thermally coupled to the second thermal wall122.

Method500may proceed with (block540) interconnecting the first set of battery cells151using a first interconnecting assembly161. Specifically, at least a portion of the first interconnecting assembly161can be inserted into the first enclosure portion115and, in some examples, attached to the intermediate edge132of the first set of side walls130. As such, this portion of the first interconnecting assembly161is surrounded and supported by the first set of side walls130. The electrical leads of the first interconnecting assembly161can be then connected to the electrical terminals of each battery cell in the first set of battery cells151. The configuration of conductive traces in the first interconnecting assembly161determines the connection scheme among the cells. Method500also comprises (block550) interconnecting the second set of battery cells152using a second interconnecting assembly162. This operation can be similar to the one described above with reference to block540. In some examples, method500further comprises (block570) installing the first cover171and (block580) installing the second cover172.

Battery Pack Examples

Referring toFIGS.6A and6B, in some examples, a battery pack600comprises a first battery-pack portion610and a second battery-pack portion620. The first battery-pack portion610and second battery-pack portion620may be also referred to as batter-pack shells, pack-enclosure portions, and the like. The second battery-pack portion620can be attached (e.g., sealably attached) to the first battery-pack portion610such that the two portions form an enclosed pack cavity605.

Battery pack600also comprises a set of battery modules100positioned within enclosed pack cavity605. Various examples of battery module100are described above with reference toFIGS.1A-3C. Each pair of adjacent battery modules100is separated by a module gap608. Furthermore, a module gap608can also extend between a battery module100and any other components of the battery pack600, a BMS module, the interior surface of the first battery-pack portion610, and the interior surface of the second battery-pack portion620. These module gap608are further described below with reference toFIGS.7A-7E. Specifically, these module gaps608can be used to evacuate any gases generated during a thermal event in one or more of battery modules100. Referring toFIG.7E, in some examples, an insulation structure609is positioned in each module gap608.

Examples of Pressure-Relief Valves in Battery Packs

Referring toFIGS.6A and6B, in some examples, the battery pack600comprises a set of pressure-relief valves650positioned in and protruding through the wall of the first battery-pack portion610. In specific examples, all pressure-relief valves650are positioned on the same portion, i.e., the first battery-pack portion610. Alternatively, a subset of the pressure-relief valves650is also positioned on the second battery-pack portion610.

Each pressure-relief valve650is configured to provide a fluid path from the enclosed pack cavity605to the environment outside of the battery pack600when the pressure inside enclosed pack cavity605is at or exceeds a set threshold. On the other hand, enclosed pack cavity605is fluidically isolated from the environment when the pressure inside enclosed pack cavity605is below the set threshold. As such, water and other environmental elements are not able to enter the pack cavity605and the battery pack600remains sealed.

This pressure (inside the enclosed pack cavity605) can increase due to a thermal event in one or more cells (positioned inside one or more of the battery modules100). The thermal event can be triggered by the internal/external short, overcharge, and the like. The thermal event can cause these cells to release gases thereby pressurizing the enclosed pack cavity605. Without the pressure release, the battery pack600can be severely damaged and cause damage to surrounding structures, e.g., an electric vehicle. It should be noted that the speed with which the gases are delivered from the battery cells150to the pressure-relief valves650is important to reduce any internal damage to the battery pack600(e.g., propagate this thermal event to other battery modules100and/or battery cells150).

In some examples, each pressure-relief valve650is coaxial with a corresponding module gap608e.g., as schematically shown inFIGS.6B and7B-7E. For example,FIG.7Eillustrates battery module100comprising one battery cell150(top right), which releases gases into module gap608. In some examples, battery cell150is separated from module gap608by module cover170, which can be specially configured to allow any gases to escape from the module enclosure (formed in part by module cover170) into module gap608. Various examples of module cover170are described above with reference to the first cover171and the second cover172. For example, the first cover171of one module may face and form a module gap608with the second cover172of the adjacent module. As noted above, an insulation structure609may be positioned in module gap608, e.g., between the module covers170as shown inFIG.7E. For example, a mica sheet (e.g., phyllosilicate) can be used as the insulation structure609.

Referring toFIGS.6B and7B, in some examples, each battery module100is positioned between two module gaps608. Specifically, each battery module100may have two sets of battery cells150, e.g., positioned on different sides of the thermal plate as described above. Each set of battery cells150is protected by a corresponding module cover (e.g., first cover171and second cover172). These module covers allow gases to escape from battery cells150and corresponding battery modules100into enclosed pack cavity605. As such, module gap608can be positioned between two module covers (e.g., first cover171of one battery module100and second cover172of the adjacent battery module100). Furthermore, each module cover can face module gap608.

Referring toFIG.7D, in some examples, pressure-relief valves650comprises a first subset of pressure-relief valves651and a second subset of pressure-relief valves652. The wall of the first battery-pack portion610comprises a first sidewall611and a second sidewall612, opposite the first sidewall611. The first subset of pressure-relief valves651is positioned in and protruding through the first sidewall611. The second subset of pressure-relief valves652is positioned in and protruding through the second sidewall612. Positioning the pressure-relief valves on both sides reduces the travel of any gases released into the module gaps608and provides an additional escape outlet as well as backup. In other words, each module gap608is serviced by two pressure-relief valves650(one valve in the first subset of pressure-relief valves651and another valve in the second subset of pressure-relief valves652). In some examples, each of the first subset of pressure-relief valves651and the second subset of pressure-relief valves652consists of five pressure-relief valves. In the same or other examples, battery pack600has only 4 battery modules100.

Examples of Liquid Cooling in Battery Packs

Referring toFIGS.8A and8B, in some examples, the battery module100of a battery pack600are liquid cooled. As described above, battery pack600comprises pack inlet tube671and pack outlet tube672used to flow a thermal fluid within battery pack600or, more specifically, to deliver this thermal fluid to each battery module100. Each battery module100is equipped with inlet port191and outlet port192, which are fluidically coupled with a thermal plate positioned between the two sets of battery cells. The design of the thermal plate and the internal liquid routing is described above.

Pack inlet tube671is fluidically coupled to inlet port191of each battery module100, while pack outlet tube672is fluidically coupled to outlet port192of each battery module100. Battery pack600can also comprise a set of controllable valves670such that each valve670provides a selective fluid pathway between pack inlet tube671and inlet port191and/or between pack outlet tube672and outlet port192.FIG.4Billustrates controllable valves670being positioned at and controlling the flow through each outlet port192. However, an example wherein controllable valves670are positioned at and control the flow through inlet port191is also within the scope. As such, the flow rate of the thermal fluid through each battery module100can be independently controlled. The operation of the controllable valves670is described below with reference toFIG.9, e.g., using temperature feedback from each battery module100.

In some examples, each controllable valve670can be replaced with a constant-flow restrictor. Each constant-flow restrictor can be selected such that the volumetric flow rate through each battery module100is the same regardless of the module position. For example, a battery module positioned the furthest from the beginning of the pack inlet tube671and the pack outlet tube672may have the least restrictive constant-flow restrictor, i.e., to compensate for pressure losses in t the pack inlet tube671and the pack outlet tube672.

Examples of Electric Vehicles and Vehicle Power Systems

FIG.9is a block diagram of an electric vehicle900comprising a vehicle power system920, in accordance with some examples. Specifically, the electric vehicle900comprises a vehicle frame910, which may support various components of the vehicle power system920, such as battery packs600. Vehicle frame910can comprise frame side rails912and frame cross-members911that interconnect frame side rails912. Vehicle frame910can also comprise support brackets913that utilize support bolts914for attaching the battery packs600or, more specifically, for attaching the support bushings680of the battery packs600. Additional details of the vehicle frame910and of various attachment options are described below with reference toFIGS.10A-11C.

Referring toFIG.9, in some examples, battery pack600, which is a part of the vehicle power system920, further comprises module temperature sensors662(e.g., thermocouples) configured to measure the temperature at one or more locations in each battery module100. The locations can be specifically selected based on the operating regime of each battery module100and/or that of the battery pack600. For example, certain battery cells150in the battery module100can be subjected to higher currents. In these examples, the module temperature sensor662can be positioned around these cells.

In some examples, battery pack600further comprises one or more temperature sensors for measuring the temperature of the thermal fluid in various locations within the battery pack600. For example, one or more temperature sensors can be positioned at the inlet port191and outlet port192of each module, e.g., to determine the heat output of each module and potentially detect and prevent various undesirable operating conditions associated with each battery module100.

In some examples, the output of various temperature sensors can be received at a battery pack controller660, which in some cases may be also referred to as a battery management system (BMS). In some examples, the battery pack controller660is also communicatively coupled to a vehicle controller960. The battery pack controller660and/or the vehicle controller960can provide operational instructions to controllable valves670(if such are used). For example, each controllable valve670can be made more open or closed (or completely opened or closed) based on the temperature reading from the module temperature sensor662. Specifically, battery pack controller660can be configured to (1) receive the temperature of the thermal fluid entering each battery module100, the temperature of the thermal fluid exiting each battery module100, and the position of each controllable valve670, and to (2) calculate the total heat transferred in each battery module100.

In some examples, the electric vehicle900also comprises a chiller-heater915for changing the temperature of the thermal fluid outside of the battery packs600. For example, a chiller-heater915can comprise a radiator for releasing heat to the environment, an air conditioning/heat pump for cooling the thermal fluid below the temperature of the environment, a heater for heating the thermal fluid, and the like. In some examples, the electric vehicle900also comprises a pump922for pumping the thermal fluid between the chiller-heater915and the battery packs600.

Examples of Integrating Battery Packs into Electric Trucks

Referring toFIGS.10A-10F and11A-11C, in some examples, battery packs600are integrated into electric vehicle900comprising a vehicle frame910. As noted above, the vehicle frame910can comprise two side rails912and set of cross-members911, each extending perpendicular to and interconnecting two side rails912. Electric vehicle900also comprises a set of battery packs600, enclosed within and attached to vehicle frame910. As such, the vehicle frame910not only supports but also protects the battery packs600(e.g., during the collision of the electric vehicle900). Furthermore, the vehicle frame910can be reinforced by the battery packs600(e.g., the battery packs600are operable as structural components of the frame910)

Various examples of battery packs600are described above. In some examples, each battery pack600comprises first battery-pack portion610, second battery-pack portion620, attached to first battery-pack portion610and forming enclosed pack cavity605with first battery-pack portion610, and set of battery modules100positioned within enclosed pack cavity605.

Referring toFIGS.10B-10D, in some examples, the battery packs600or, more specifically, the second battery-pack portion620comprises support bushings680for attaching to the vehicle frame910. Each support bushing680can be positioned adjacent to one corner of the second battery-pack portion620. Referring toFIG.10D, in some examples, support bushing680comprises (a) rigid bushing enclosure682bolted to the wall of second battery-pack portion620, and (d) elastomeric bushing684supported and surrounded by rigid bushing enclosure682. Referring toFIG.10C, in some examples, support bushing680is pivotably attached to support bracket913by a support bolt914that protrudes through support bushing680. In this example, the support bolt914extends parallel to the cross-members911and parallel to the frame plane (the X-Y plane).FIGS.10E and10Fillustrate another example of the support bushing680, which is configured to receive a support bolt914(not shown) extending perpendicular to the cross-members911and perpendicular to the frame plane (the X-Y plane). This example may simplify the process of mounting of battery packs600on the frame and may also provide more damping (using the elastomeric bushing684) in the direction perpendicular to the frame plane (the X-Y plane).

FIG.11Ais a schematic perspective view of frame910and a set of battery packs600, with two packs stacked in the front portion of frame910, in accordance with some examples.FIG.11Bis a schematic side view of frame90and the two stacked battery packs ofFIG.11A, whileFIG.11Cis a corresponding front view. Specifically, the first battery pack601is positioned within frame910, e.g., between the side rails912. The second battery pack602is positioned above frame910and is connected to the frame by a pack-supporting structure. This pack configuration is particularly beneficial for electric trucks, which tend to have uneven weight distribution when loaded.

CONCLUSION

Although the foregoing concepts have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing processes, systems, and apparatuses. Accordingly, the present embodiments are to be considered illustrative and not restrictive.