Cell biasing method for battery

Abstract

A battery pack is provided and includes: a pack case defining a pair of side walls; and a plurality of modules positioned in a row along the side wall in the battery pack housing. Each of the modules includes a module housing extending between the sidewalls. Each of the modules includes a first plurality of cells that are all electrically connected to one another, and a second plurality of cells that are all electrically connected to one another and electrically isolated from the first plurality of cells. A cell biasing member biases the cell toward the bus bar to improve connectivity, and a tie bar prevents deformation of the module due to thermal expansion.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a divisional application of U.S. Provisional Patent Application No. 63 / 367,185 filed on June 28, 2022, U.S. Provisional Patent Application No. 63 / 367,182 filed on June 28, 2022, U.S. Provisional Patent Application No. 63 / 444,173 filed on February 8, 2023, U.S. Provisional Patent Application No. 63 / 463,015 filed on April 29, 2023, and U.S. Provisional Patent Application No. 63 / 463,298 filed on May 1, 2023, and the entire contents of all U.S. Provisional Patent Applications are incorporated into this application by reference where permitted. Technical Field

[0003] The present description relates generally to battery packs, and more particularly to battery packs having immersion cooled cells, optionally for use in electric vehicles or for other applications such as in stationary settings for power storage and consumption. Background Art

[0004] Battery packs for electric vehicles and for other applications such as stationary applications suffer from many problems. Some battery packs may experience thermal runaway, which endangers anyone nearby. Some battery packs are difficult to manufacture and difficult or virtually impossible to disassemble in a manner that allows the cells contained therein to be used for another purpose or for replacing any of the cells. Some battery packs are relatively heavy and have a low cell density. There are other problems as well. Improved battery packs are desired. Summary of the invention

[0005] In one aspect, the present disclosure relates to a module for a battery pack, comprising: a module housing and a plurality of battery cells, wherein the module housing comprises a first module housing member and a second module housing member, wherein the module housing defines a battery cell chamber for holding the plurality of battery cells and a quantity of cooling fluid, wherein the second module housing member has a plurality of tie rod holes therethrough; a plurality of bus bars in the housing, the plurality of bus bars electrically connecting the battery cells in a combination of series electrical connections and parallel electrical connections; at least one battery cell biasing member, the at least one battery cell biasing member being positioned to urge the battery cells and the bus bars into engagement with each other with at least a selected engagement force; and a plurality of tie rods, wherein the tie rods from Each of the plurality of tie rods has a first end and a second end, and wherein the first end has a first connection with a first end member engaged with a first module housing member, and wherein the second end has a second connection with a second end member engaged with a second module housing member, such that the first end member and the second end member apply a selected clamping force on the first module housing member and the second module housing member, wherein at least one of the first connection and the second connection is a threaded connection such that the second end member can be rotated by a tool until a selected torque is reached, the selected torque indicating that any of the plurality of battery cells that are proximate to the tie rod are engaged with each other with at least the selected engagement force.

[0006] On the other hand, the present disclosure relates to a module for a battery pack, comprising: a module housing; a plurality of battery cells positioned in the module housing, each of the battery cells comprising a positive terminal and a negative terminal; a bus bar electrically connecting the positive terminals on the battery cells from a first subset of the plurality of battery cells and the negative terminals on the battery cells from a second subset of the plurality of battery cells; a battery cell biasing member positioned to engage with all of the battery cells of the first subset and one of the battery cells of the second subset separately from the bus bar, and electrically connected in parallel to the negative terminals of all of the battery cells of the first subset and one of the battery cells of the second subset, wherein the battery cell biasing member urges all of the battery cells of the first subset and one of the battery cells of the second subset toward the bus bar.

[0007] In yet another aspect, the present disclosure relates to a module for a battery pack, comprising: a module housing and a plurality of battery cells, wherein the module housing comprises a first module housing member and a second module housing member, wherein the module housing defines a battery cell chamber for holding the plurality of battery cells and a quantity of cooling fluid, wherein the second module housing member has a plurality of tie rod holes extending therethrough; a plurality of bus bars in the housing, the plurality of bus bars electrically connecting the battery cells in a combination of series electrical connections and parallel electrical connections; at least one biasing member, the at least one biasing member being positioned to apply a biasing force to cause the battery cells and the bus bars to engage with each other with at least a selected engagement force; and wherein the plurality of biasing members extend over a range of values ​​between a low height value and a high height value, wherein the low height value and the high height value depend at least in part on a tolerance of a cell height of the battery cells, and wherein the biasing force varies between a low biasing force at one of the low height value and the high height value and a high biasing force at the other of the low height value and the high height value, and wherein a ratio of the low biasing force to the high biasing force is less than a ratio of the low height value to the high height value.

[0008] On the other hand, the present disclosure relates to a module for a battery pack, comprising: a module housing, the module housing defining a sealed fluid retaining space for retaining a certain amount of cooling fluid; a plurality of battery cells positioned in the module housing, each of the battery cells including a positive terminal and a negative terminal; a bus bar in the fluid retaining space, wherein the bus bar electrically connects the positive terminals on the battery cells from a first subset of the plurality of battery cells and the negative terminals on the battery cells from a second subset of the plurality of battery cells; a voltage tap engaged with the bus bar, wherein the voltage tap is molded into the housing; and a module controller mounted to the outside of the module housing, wherein the voltage tap engages with the module controller to send a signal to the module controller.

[0009] In yet another aspect, the present disclosure relates to a battery pack comprising: a battery pack housing; a plurality of modules, the plurality of modules being positioned in the battery pack housing and horizontally spaced apart, wherein each of the modules comprises a module housing defining a coolant holding space for holding an amount of coolant and a plurality of battery cells positioned in the module housing; a coolant supply line, the coolant supply line being fluidly connected to a coolant source and the coolant holding spaces of at least two of the modules; wherein the coolant supply line is fluidly connected in parallel to at least two of the modules; and wherein the coolant supply line is contained in the battery pack housing, outside the module housing, and connected to the top side of the module housings of at least two of the modules.

[0010] On the other hand, the present disclosure relates to a busbar for a battery module including battery cells having battery cell terminals, the busbar comprising: a first contact surface for contacting the battery cell terminals, wherein the contact surface is textured (e.g., recessed, grooved) to define: a first upper portion; a second upper portion; and a lower portion; wherein the lower portion is horizontally disposed between the upper portions and connects the upper portions; wherein the upper portion is disposed above the lower portion, with a first vertical distance (h-min: for example, can be 0.3 mm) and a second vertical distance (h-max) greater than the first vertical distance between the upper and lower portions; and wherein the upper portions are separated by a first horizontal dimension (w-min: for example, can be 1.0 mm) and a second horizontal dimension (w-max) greater than the first horizontal dimension.

[0011] On the other hand, the present disclosure relates to a method of operating a battery pack including a module, the module including a module housing, the module housing including a first module housing member and a second module housing member, and the module containing a bus bar in contact with a plurality of battery cells, the method comprising: regulating the temperature of the plurality of battery cells using a cooling liquid flowing through the module housing and in which the plurality of battery cells are immersed; charging or discharging the battery pack at a rate of at least 2C; removing one or more of the plurality of battery cells from the battery pack by removing the second module housing member from the first housing member to disengage the bus bar from the plurality of battery cells, thereby electrically disconnecting the plurality of battery cells from each other; and replacing one or more of the removed battery cells with one or more replacement battery cells.

[0012] On the other hand, the present disclosure relates to a battery pack, comprising: a battery pack housing defining a pair of side walls; and a plurality of modules, the plurality of modules being positioned in the battery pack housing in rows along the side walls, wherein each of the modules includes a module housing extending between the side walls; wherein each of the modules contains a first plurality of battery cells that are all electrically connected to each other, and a second plurality of battery cells that are all electrically connected to each other and electrically isolated from the first plurality of battery cells.

[0013] In yet another aspect, the present disclosure relates to a battery pack comprising: a battery pack housing; a plurality of modules positioned in the battery pack housing, wherein each of the modules comprises a module housing defining a cell chamber containing a plurality of battery cells and having an upper surface defining at least one module housing cooling fluid inlet; a coolant supply hose fluidly connected in parallel with a cooling fluid source and the module housing cooling fluid inlets of at least two of the modules; and wherein the coolant supply hose is contained in the battery pack housing, outside the module housing.

[0014] On the other hand, the present disclosure relates to a busbar for a battery module including battery cells having battery cell terminals, the busbar comprising: a contact surface for contacting the battery cell terminals, wherein the contact surface is textured to define a plurality of contact surface portions, and a plurality of recesses between adjacent contact surface portions in the contact surface portions, wherein the recesses have a depth of at least 0.2 mm from the contact surface portions and a width of at least 0.2 mm.

[0015] On the other hand, the present disclosure relates to a battery pack system for an electric vehicle, comprising: a plurality of battery packs, wherein each battery pack includes a plurality of battery cells for storing an electric charge for powering a traction motor of the electric vehicle; a thermal management system for the plurality of battery packs, the thermal management system conveying a cooling fluid through the battery packs; a plurality of valves, the plurality of valves controlling the flow of cooling fluid to each battery pack in the battery packs; a control system, the control system being operably connected to the valves to control the operation of the valves, thereby controlling the flow of cooling fluid to each battery pack in the battery packs; at least one sensor in each battery pack in the battery packs, the at least one sensor sending a signal to the control system, wherein the signal indicates whether any battery cell of any battery pack in the battery pack is at risk of thermal runaway; wherein the control system includes a processor and a memory, the memory containing program code executable to perform the following operations: based on the signal, operating the plurality of valves to increase the flow of cooling fluid to one battery pack in the battery packs and to reduce the flow of cooling fluid to other battery packs so as to suppress thermal runaway.

[0016] On the other hand, the present disclosure relates to a battery pack system for an electric vehicle, comprising: a first battery pack and a second battery pack, wherein each of the first battery pack and the second battery pack includes a plurality of battery cells for storing an electric charge for powering a traction motor of the electric vehicle; a thermal management system for the first battery pack and the second battery pack, the thermal management system conveying a cooling fluid through the first battery pack and the second battery pack; a plurality of valves, the plurality of valves controlling the flow of cooling fluid to each of the first battery pack and the second battery pack; a control system, the control system being operably connected to the valves to control the operation of the valves, thereby controlling the flow of cooling fluid to each of the first battery pack and the second battery pack; a sensor arrangement, the sensor arrangement sending a signal to the control system, wherein the signal indicates whether any of the plurality of battery cells in the first battery pack is at risk of thermal runaway. and whether any of the plurality of battery cells in the second battery pack is at risk of thermal runaway; wherein the control system comprises a processor and a memory, and wherein the memory contains program code capable of being executed by the processor to perform the following operations: a) based on the signal, determining whether the first battery pack is at risk of thermal runaway; b) based on the signal, determining whether the second battery pack is at risk of thermal runaway; c) based on the determination in steps a) and b) that the first battery pack is at risk of thermal runaway and the second battery pack is not at risk of thermal runaway, operating multiple valves to increase the flow of cooling fluid to the first battery pack and reduce the flow of cooling fluid to the second battery pack; and d) based on the determination in steps a) and b) that the first battery pack is at risk of thermal runaway and the second battery pack is not at risk of thermal runaway, operating multiple valves to increase the flow of cooling fluid to the first battery pack and reduce the flow of cooling fluid to the second battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] For a better understanding of the embodiments described herein and to more clearly show how the embodiments may be practiced, reference will now be made to the accompanying drawings, by way of example only.

[0018] Figure 1 An electric vehicle with a battery pack connected to a charging station is shown.

[0019] Figure 2 is a perspective view of an embodiment of a battery pack of the present disclosure.

[0020] Figure 3 yes Figure 2 A perspective view of a battery pack with the top battery pack housing member separated from the rest of the battery pack.

[0021] Figure 4 yes Figure 2 Schematic depiction of the electrical connections of multiple cells in multiple modules in a battery pack.

[0022] Figure 5 yes Figure 2 A perspective view of a module of a battery pack with the cooling fluid inlet and outlet hoses, CMU and associated cables removed.

[0023] Figure 6 is along Figure 5 A cross-sectional perspective view of a portion of a module at section line AA.

[0024] Figure 7 is along Figure 5 A cross-sectional perspective view of a portion of a module of section line BB.

[0025] Figure 8 yes Figure 2 Schematic depiction of the cooling fluid supply and return hoses for the modules in a battery pack.

[0026] Fig. 9 yes Figure 2 A perspective view of the bottom side of an embodiment of a negative bus bar terminal of a bus bar of a battery pack.

[0027] Fig.10 yes Figure 2 A perspective view of the bottom side of an embodiment of a positive bus bar terminal of a bus bar of a battery pack.

[0028] Fig.11 yes Fig. 9 Negative bus terminal or Fig.10 A side elevation view at an enlarged scale of a portion of the contact surface of the positive busbar terminal.

[0029] Fig.12 yes Figure 2 Another perspective view of a module of a battery pack.

[0030] Fig.13 yes Fig.12 An exploded perspective view of the module.

[0031] Fig.14 yes Fig.12 An exploded perspective view of the upper part of the module.

[0032] Fig.15 yes Fig.12 An exploded perspective view of the battery cells and lower part of the module.

[0033] Fig.16A yes Fig.12 A perspective view of a module with a cover assembly of the module removed to show the internal components of the module.

[0034] Fig. 16B yes Fig.12 A top view of a module with a cover assembly of the module removed to show the internal components of the module.

[0035] Fig.17 yes Fig.12 A perspective cross-sectional view of a module showing the cell retaining structure of the module.

[0036] Fig.18 yes Fig.12 Another perspective cross-sectional view of a module showing the cell retaining structure of the module.

[0037] Fig.19 yes Figure 2 A perspective view of one of the cells in a battery pack.

[0038] Fig. 20 is with Figure 2 Some subset of the cells in the battery pack are in contact with Figure 2 A perspective view of the bus bars of a battery pack.

[0039] Fig.21 yes Figure 2 A perspective view of some of the bus bars and cells of a battery pack.

[0040] Fig. 22 yes Figure 2 A perspective view of a first embodiment of a cell biasing member of a battery pack.

[0041] Fig.23 yes Figure 2 0026] A perspective view of a second embodiment of a battery cell biasing member of a battery pack.

[0042] Fig.24 yes Figure 2 A perspective view of a third embodiment of a battery cell biasing member of a battery pack.

[0043] Fig.25 It is shown for Figure 2 A perspective view of the multiple voltage taps of a battery pack.

[0044] Fig.26 is a schematic layout of a thermal management system in a multi-pack system including a plurality of battery packs according to an embodiment of the present disclosure.

[0045] Fig. 27 is used for Fig.26 Schematic layout of the control system of the thermal management system shown in .

[0046] Fig.28 is a schematic layout of the thermal management system when operating in heating mode.

[0047] Fig.29 is a schematic layout of the thermal management system when operating in passive cooling mode.

[0048] Fig.30is a schematic layout of the thermal management system when operating in active cooling mode.

[0049] Fig.31 is a schematic layout of the thermal management system when operating in the secondary cooling medium charging mode.

[0050] Fig.32 is a schematic layout of the thermal management system when operating in the blackout mode.

[0051] Fig.33 is a schematic layout of the thermal management system when operating in passive cooling mode.

[0052] Fig.34 is a schematic layout of an alternative layout of a thermal management system.

[0053] Fig.35 is a schematic layout of another alternative layout of the thermal management system. DETAILED DESCRIPTION

[0054] explain

[0055] For simplicity and clear illustration, figure numerals may be repeated in the accompanying drawings to indicate corresponding or similar elements where deemed appropriate. In addition, many specific details are set forth in order to provide a thorough understanding of one or more embodiments described herein. However, it will be appreciated by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other cases, well-known methods, processes, and components are not described in detail to avoid obscuring the embodiments described herein. It should first be understood that, although exemplary embodiments are shown in the drawings and described below, the principles of the present disclosure may be implemented using any number of technologies, whether or not these technologies are currently known. The present disclosure should by no means be limited to the exemplary implementations and technologies illustrated in the drawings and described below.

[0056] Unless the context indicates otherwise, the various terms used throughout this specification may be read and understood as follows: "or" as used throughout is inclusive, just as if written as "and / or"; singular articles and pronouns used throughout include their plural forms and vice versa; similarly, gender pronouns include their counterparts, so that the pronouns should not be understood as limiting anything described herein to use, implementation, performance, etc. by a single gender; "exemplary" should be understood as "illustrative" or "illustrative", and not necessarily "preferred" over other implementations. Other definitions of terms may be listed herein; as will be understood by reading this specification, these definitions may apply to previous and subsequent instances of those terms.

[0057] Without departing from the scope of the present disclosure, the systems, devices and methods described herein may be modified, added or omitted. For example, the components of the systems and devices may be integrated or separated. In addition, the operation of the systems and devices disclosed herein may be performed by more, less or other components, and the described methods may include more, less or other steps. In addition, the steps may be performed in any suitable order. As used in this document, "each" refers to each member in a set or each member in a subset of a set.

[0058] The indefinite article "a" is not intended to be limited to referring to "one" of an element. Where applicable, it is intended to refer to "one or more" of an element (ie, unless it is clear from the context that only one of the elements is appropriate).

[0059] Any reference to up, down, top, bottom, etc. is intended to refer to the orientation of a particular element during use of the claimed subject matter, and not necessarily its orientation during shipping or manufacturing. For example, the upper surface of an element can still be considered the upper surface of the element even when the element is lying on its side.

[0060] General battery pack

[0061] Reference Figure 1 , Figure 1 A battery pack 10 is shown for an electric vehicle 11. The term "electric vehicle" is intended to include any vehicle that includes an electric motor 13 that drives one or more wheels 15 of the vehicle 11. In addition to the battery pack 10, the vehicle 11 may include any other suitable type of energy storage device. The electric motor 13 may operate alone, or may be one of a plurality of electric motors. In addition, the vehicle 11 may include other types of power devices, such as an internal combustion engine.

[0062] Figure 1 The vehicle 11 shown in the figure is a car, however, it will be understood that the vehicle 11 can be any other suitable type of vehicle, such as a minivan, a pickup truck, a commercial van or truck, a bus, an SUV, an ATV, a tracked or wheeled engineering vehicle such as an excavator, a backhoe loader, a bulldozer or a bobcat. The vehicle can also be a ship or an aircraft. The vehicle can be remotely operated or operated by a driver. The vehicle can be fully automatic or partially automatic, or not automatic. The vehicle can carry one or more people and / or cargo, or it can carry nothing.

[0063] exist Figure 1 , the vehicle 11 is shown plugged into a charging station 19 .

[0064] Reference Figure 2 and Figure 3 , Figure 2 and Figure 3 A battery pack 10 is shown. The battery pack 10 includes a battery pack housing 20, a plurality of modules 22, a thermal management system 24, and a battery pack control system 26.

[0065] The battery housing 20 may include a bottom battery housing member 20a and a top battery housing member 20b, which is mounted to the bottom battery housing member 20a via a plurality of mechanical fasteners. The bottom battery housing member 20a may be in the form of a barrel, having a bottom and a plurality of side walls, and may be filled with or hold a certain amount of liquid if desired. The top battery housing member 20b may be a generally flat plate. The battery housing 20 may be formed of any suitable material, such as aluminum or a suitable polymer material.

[0066] In the illustrated embodiment, the battery pack housing 20 has a substantially rectangular prismatic shape. The bottom battery pack housing member 20a has: two elongated side walls 100 extending in the horizontal longitudinal direction and two end walls 102 extending in the horizontal transverse direction perpendicular to the longitudinal direction; and a floor member 103. In other embodiments, the battery pack housing 20 may have other shapes. The modules 22 are arranged in rows in the battery pack housing 20 along the horizontal longitudinal direction. In the illustrated embodiment, the battery pack 10 has eight modules 22, which are arranged in a barrel formed by the bottom battery pack housing member 20a. However, in other embodiments, the battery pack 10 may have any other suitable number of one or more modules 22.

[0067] General Module

[0068] Reference Figures 12 to 15 , Figures 12 to 15 One of the modules 22 is shown. Fig.12 is a perspective view of module 22 . Fig.13 is an exploded view of the components of module 22 . Fig.14 is an exploded view of the cover assembly 500 of the module 22, and Fig.15 5 is an exploded view of the lower portion 501 of the module 22. Each module 22 includes a module housing 502 and a plurality of cells 503. The module 22 may also include a plurality of bus bars 528, a plurality of voltage taps 530, a plurality of tie rods 532, and a plurality of module terminals 534, which may all form part of the cap assembly 500. The module 22 may also include a plurality of cell biasing members 536. The module may also include a module control system 700, which includes at least one controller 702.

[0069] Module housing

[0070] The module housing 502 may include a first module housing member 502a and a second module housing member 502b. In the illustrated embodiment, the first module housing member 502a forms an upper cover member, and the second module housing member 502b forms a lower barrel member. The first module housing member 502a and the second module housing member 502b may be connected at a joint 504 ( Fig.12 ) are sealed and connected to each other in sequence at the first and second module housing members 502a and 502b to prevent leakage of cooling fluid between the first module housing member 502a and the second module housing member 502b. The module housing 502 defines a cell chamber 505 in which the cell 503 is positioned. The cell chamber 505 contains a cooling fluid when in use, and the cell 503 is immersed in the cooling fluid to control the temperature of the cell 503.

[0071] The cooling fluid can be any suitable dielectric fluid that can flow through the battery cell chamber 505 to transfer heat with the battery cells 503 (i.e., to and from the battery cells 503) and prevent current from being transferred between the battery cells 503 through the cooling fluid. The cooling fluid is preferably a liquid so as to have a relatively high heat capacity, but in some embodiments, the cooling fluid can be a gas, such as a suitable refrigerant.

[0072] In the illustrated embodiment, a sealing member 505 is present at the joint 504 between the first module housing member 502a and the second module housing member 502b to assist in preventing leakage of cooling fluid between the first module housing member 502a and the second module housing member 502b.

[0073] Reference Fig.18 , the module housing 502 includes a cell retaining structure shown at 506 , which may be any suitable structure for retaining the cell 503 in place and keeping the cell 503 physically separated from each other.

[0074] The cell retaining structure 506 may include a cell retainer plate 508, which is provided on (eg Fig.17 The battery pack 10 is sandwiched between the first module housing member 502a and the second module housing member 502b at selected locations around the periphery of the cell retainer plate 508 (shown as positions 510 in FIG. 1 ). The cell retainer plate 508 has a plurality of cell retaining holes 512, each of which is sized to tightly retain one of the battery cells 503. Each cell retaining hole 512 includes a plurality of cooling fluid through-holes 514 to allow cooling fluid to flow across the cell retainer plate 508 during operation of the battery pack 10.

[0075] The cell retaining structure 506 also includes a plurality of gap protrusions 516 extending upward from the bottom plate 518 of the housing 502 to surround each of the battery cells 503. The cell retaining holes 512 and the gap protrusions 516 in the cell retainer plate 508 cooperate to hold each battery cell 503 in a selected position and to keep the plurality of battery cells 503 physically separated from each other to prevent short circuits between the battery cells 503. It will be appreciated that any other suitable cell retaining structure 506 may alternatively be used to hold the battery cells 503 in place and physically separated from each other.

[0076] In the illustrated embodiment, the module housing 502 has a substantially rectangular prismatic shape. The module housing 502 has two side walls 104 extending in a horizontal longitudinal direction parallel to the side walls 100 of the bottom battery pack housing member 20a, and two end walls 106 extending in a horizontal transverse direction parallel to the end walls 102 of the battery of the bottom battery pack housing member 20a. The module housing 502 extends in a transverse direction from one of its side walls 100 across the battery pack housing 20 to the other of its side walls 100.

[0077] Battery Cell

[0078] Reference Fig.19 , each battery cell 503 includes a battery cell body 518 having a first end 520 and a second end 522. In the illustrated embodiment, the first end 520 is the top of the battery cell and the second end 522 is the bottom of the battery cell, however it will be understood that in other embodiments, the battery cell 503 may be oriented differently, such as horizontally, for example. The battery cell 503 also includes a negative battery cell terminal 526 and a positive battery cell terminal 524 present at the first end 520. The negative terminal 526 encloses the entire battery cell 503 except for the central portion of the first end 520, wherein the positive battery cell terminal 524 is positioned at the central portion. As can be seen, the negative battery cell terminal 526 includes a peripheral portion of the first end 520.

[0079] Because both the positive cell terminal 524 and the negative cell terminal 526 are positioned at the first end 520 of the cell 503, all of the cells 503 can be positioned in the module housing 502 in the same orientation (e.g., with the first end facing upward (i.e., the top of the cell, as described above)). This reduces the possibility of errors during the insertion of the cells 503 into the module housing 502 during assembly of the module 22 or during replacement of one or more cells 503 in the module 22.

[0080] In the illustrated embodiment, the positive cell terminals 524 of the cells 503 are supported by a plurality of supports 523 separated by gaps 525. Below the positive cell terminals 524 is a burst disc 527 that allows the cells 503 to vent through the gaps 525 without exploding if the internal pressure within the cell body 518 exceeds a selected pressure.

[0081] The cells 503 may be any suitable type of electrochemical cells, such as those supplied by LG Chem or by Panasonic. The cell body 518 may be cylindrical as shown or may have any other suitable shape. Each cell may have a voltage of about 4V when fully charged.

[0082] Each battery cell 503 has a battery cell height Hc between the first end 520 and the second end 522. Tolerances may exist in the manufacture of the battery cells 503, so that the battery cell height Hc may vary between the battery cells 503.

[0083] Description of busbars and individual cells in a module

[0084] The module 22 may also include a plurality of bus bars 528, a plurality of voltage taps 530, a plurality of tie rods 532, and a plurality of module terminals 534, which may all form part of the cap assembly 500. The module 22 may also include a plurality of cell biasing members 536.

[0085] Bus bars 528 connect subsets of cells 503 to other subsets of cells 503. Each subset is shown at 538. A first subset of subsets 538 shown at 538a may be referred to as a first subset 538a of cells 503, a second subset of subsets 538 of cells 503 may be referred to as a second subset 538b of cells 503, a third subset of subsets 538 of cells 503 may be referred to as a third subset 538c of cells 503, etc. Each subset 538 of cells 503 is unique in the sense that each subset 538 does not contain cells 503 in common with any other subset of subsets 538.

[0086] The first bus bar in bus bar 528 is Fig. 20528a and may be referred to as a first bus bar 528a, a second bus bar in the bus bar 528 may be referred to as a second bus bar 528b, etc. The first bus bar 528a joins the positive cell terminals 524 of the first subset 538a of the battery cells 503 and the negative cell terminals 526 of the second subset 538b of the battery cells 503. Similarly, the second bus bar 528b joins the positive cell terminals 524 of the second subset 538b of the battery cells 503 and the negative cell terminals 526 of the third subset 538c of the battery cells 503. This pattern continues throughout the multiple battery cells 503 of the module 22 until the last of the bus bars 528 (referred to as the last bus bar, which in this embodiment is the eleventh bus bar 528k) joins the positive cell terminal 524 of the second-to-last subset of the subsets of battery cells 503 (which in this embodiment is the eleventh subset shown as 538k) and the negative cell terminal 526 of the last subset of the subsets of battery cells 503 (which in this embodiment is the twelfth subset shown as 538b).

[0087] It will be noted that the cells 503 constituting each subset 538 are connected in parallel via associated bus bars 528, and each subset 538 of cells 503 is connected in series to a subsequent subset 538 of cells 503. In the present example, the plurality of cells 503 in the module 22 are connected in a 12s12p configuration. In other words, there are one hundred and forty-four cells 503 consisting of twelve subsets 538 of twelve cells 503. The twelve cells 503 of each subset 538 are connected in parallel to one another. The cells 503 of each subset of the twelve subsets 538 of cells 503 are connected in series to the cells 503 of the subsequent subset of the subset 538 of cells 503. However, any other suitable number of cells 503 may constitute the plurality of cells 503, and they may be connected in any suitable configuration, as is known in the battery module art.

[0088] In the present embodiment, each subset 538 is shown as a single row of cells 503. However, it will be understood that each subset 538 may be any other arrangement of cells, such as a zigzag arrangement of cells 503, or a group of cells 503 including cells 503 from multiple rows of cells 503.

[0089] Module 22 also includes a first bus bar end member 540 that connects the negative terminal 526 of the first subset 538a of the cells 503 to a first module terminal shown at 534a among the module terminals. Module 22 also includes a second bus bar end member 541 that connects the positive terminal 526 of the last subset 538I of the cells 503 to a second module terminal shown at 534b among the module terminals. A first module terminal 534a among the module terminals 534 extends through a module terminal hole 542 in the module housing 502 (in this embodiment, through the second module housing member 502b) for connection to a second module terminal 534b among the module terminals 534 of the previous module in module 22. The second module terminal 534b of the module terminals 534 extends through another module terminal hole 542 in the module housing 502 (in the present embodiment, through the second module housing member 502b) for connection to the second module terminal 534a of the module terminal 534 of the next module in the module 22.

[0090] The first bus bar end member 540 may be connected to the first module terminal 534a in any suitable manner, such as by a mechanical connection or by welding, soldering, brazing, etc. Similarly, the second bus bar end member 541 may be connected to the second module terminal 534b in any suitable manner, such as by a mechanical connection or by welding, soldering, brazing, etc.

[0091] The plurality of cells 503 may be a group identified by 544. The plurality of cells 503 544 may be a first plurality of cells. The module 22 may also include a second plurality of cells 503 identified by 546. In the illustrated embodiment, each module 20 has two hundred and eighty-eight cells 503, wherein each of the plurality of cells 503 544 and the second plurality of cells 503 546 is composed of one hundred and forty-four cells 503. Within each of the first plurality of cells 503 544 and the second plurality of cells 503 546, the cells 503 are connected in a "12s12p" configuration as previously described. The second plurality of cells 503-546 has another plurality of bus bars 528 associated therewith, another first bus bar end member 540 connecting the negative terminal 526 of the first subset 538a of the cells 503 in the second plurality of cells 503-546 to another first module terminal 534a, and another second bus bar end member 541 connecting the positive terminal 526 of the last subset 538I of the cells 503 in the second plurality of cells 503-546 to another second module terminal 534b. As can be seen, with respect to the isolated module 22 (rather than the battery pack 10 as a whole), the first plurality of cells 503-544 are all electrically connected to each other, and the second plurality of cells 503-546 are all electrically connected to each other and electrically isolated from the first plurality of cells 503-544.

[0092] The first plurality of battery cells 503 544 and the second plurality of battery cells 503 546 may be separated by a partition wall, shown at 548, to reduce the likelihood of an unintentional electrical connection being formed between any battery cell 503 from the first plurality 544 and any battery cell 503 from the second plurality 546, since the voltage that may exist during such an unintentional connection may be very high (hundreds of volts). The partition wall 548 may include a first portion 548a formed directly as part of the first module housing member 502a and a second portion 548b formed directly as part of the cell retainer plate 508.

[0093] about Fig.21 The busbars 528 are further described in detail. Each busbar 528 is mounted to the second module housing member 502b by any suitable means. For example, each busbar 528 optionally includes at least one clamping hole 549 that receives a clamp 550 molded into the second module housing member 502b. The busbars 528 include a plurality of negative busbar terminals 552 positioned to engage the negative cell terminals 526 of the battery cells 503, and a plurality of positive busbar terminals 554 positioned to engage the positive cell terminals 524 of the battery cells 503.

[0094] like Fig.18 As shown, the negative bus bar terminal 552 is directly adjacent to the support surface 556 of the second module housing member 502b. Therefore, when engaged, there is substantially no elasticity between the negative bus bar terminals 552. The positive bus bar terminal 554 is held by a positive cell terminal support 558 extending between the positive bus bar terminal 554 and the negative bus bar terminal 552. The positive bus bar terminal supports 558 each have a plurality of bends 559 therein and are elastically flexible. In addition, the positive bus bar terminal support 558 is spaced apart from the second module housing member 502b so as to provide freedom of movement for the positive bus bar terminal support 558. Therefore, the positive bus bar terminal support 558 is a positive bus bar terminal biasing member that causes the positive bus bar terminal 554 to engage with the positive cell terminal 524 of the cell 503.

[0095] In an embodiment where the positive cell terminal 524 of the battery cell 503 is supported by multiple supports 523, it is advantageous that the positive bus bar terminal 554 is held by a resiliently flexible positive bus bar terminal support 558 to reduce the possibility of applying such a large force to the positive cell terminal 524 that the support 523 collapses.

[0096] It will be noted that upon removal of the second module housing member 502b, all of the bus bars 528 are removed from the battery cells 503. Thus, in at least some embodiments, the battery cells 503 are electrically disconnected from one another, thereby reducing the likelihood of injury to service personnel or assembly line workers when contacting the battery cells.

[0097] Biasing member with low force variation

[0098] The plurality of cell biasing members 536 are described in further detail below. Fig.15 , it can be seen that there is a biasing member 536 for each battery cell 503 .

[0099] The plurality of cell biasing members 536 are positioned to urge each of the cells 503 and each of the positive bus bar terminal 554 and the negative bus bar terminal 552 from the bus bar 528 into engagement with each other with at least a selected engagement force.

[0100] When the cell biasing members 536 urge the cell and busbar terminals 554 and 552 to engage each other, the cell biasing members 536 each have a biasing member height Hb. The biasing member height Hb of the cell biasing members 536 extends within a range of values ​​between a low height value and a high height value. The low height value and the high height value depend in part on the tolerance of the cell height Hc of the cell.

[0101] The cell biasing members 536 can each have any suitable shape so as to provide a biasing force that varies less than a selected amount (e.g., 30% of the biasing force provided at a high value of the cell biasing member height Hb) over a range of height values. In another aspect, the properties of the cell biasing members 536 can be characterized as follows: the biasing force varies between a low biasing force at one of the low height values ​​and the high height values ​​and a high biasing force at the other of the low height values ​​and the high height values. An advantageous property of the cell biasing members 536 is that the ratio of the low biasing force to the high biasing force is less than the ratio of the low height value to the high height value.

[0102] The cell biasing member 536 is positioned at the second end 522 (ie, the bottom end) of the cell 503 , between the cell 503 and the first module housing member 502 a .

[0103] It will be understood that Fig.15 The shape of the cell biasing member 536 in FIG. 5 is only one example of a suitable shape. Different shapes for the cell biasing member 536 may be used, such as Fig. 22 , Fig.23 and Fig.24 Any of the shapes shown in .

[0104] It can be seen that Fig.18 , Fig. 22 and Fig.23 The cell biasing members 536 shown in FIG. 5 all operate in flexure, rather than simply in tension or compression.

[0105] The cell biasing members 536 may be connected to one another so as to be formed together as one piece in a single molding process, particularly in the case of Fig.15 and Fig. 22 In the illustrated embodiment, the cell biasing members 536 are formed together as one sheet from a suitable polymeric material, such as a suitable elastomer.

[0106] The battery cell biasing components are electrically connected in parallel

[0107] In some embodiments, Fig.23 and Fig.24 As shown, the cell biasing members 536 are made of a conductive material such as a suitable steel. In addition, the cell biasing members 536 can be connected together. This allows the cell biasing members 536 to be used as a parallel connection with the negative cell terminals 526 of all cells 503 in a particular subset 538. In the unlikely event that a particular negative bus bar terminal 552 does not properly engage with a particular cell 503 (or does not engage at all), this provides a current flow path through all cells 503 in a given subset 538.

[0108] Tie rod

[0109] Reference Fig.18 The tie rod 532 is further described in detail. The tie rod 532 has a first end 560 and a second end 562. The first end 560 is connected to a first end member 564 at a first connection 563, and the first end member 564 is positioned to engage with the first module housing member 502a. The second end 562 of the tie rod 532 is connected to a second end member 568 at a second connection 566, and the second end member 568 is positioned to engage with the second module housing member 502b. The tie rod 532, in combination with the first end member 564 and the second end member 568, holds the second module housing member 502b in place to inhibit the second module housing member 502b from bending due to pressure from the cooling fluid therein and the engagement force between the battery cell 503 and the bus bar 528.

[0110] At least one of the first connection and the second connection is a releasable threaded connection. The other of the first connection 563 and the second connection 566 may be a releasable threaded connection, alternatively may be some other type of releasable connection such as a bayonet connection, for example, or may be a permanent connection.

[0111] The first end member 564 can be retained in the first module housing member 502a in any suitable manner, such as by being non-rotatably press-fitted into the insert receiving hole 566. A sealing member 567 (e.g., an o-ring) can be positioned between the first end member 564 and the first module housing member 502a to prevent leakage of cooling fluid from the battery cell chamber 505. As another alternative, the first end member 564 can be molded directly into the first module housing member 502a.

[0112] The second end member 568 is removable from engagement with the second module housing member 502b. In the illustrated embodiment, the second end member 568 is permanently connected to the second end 562 of the tie rod 532, and the first connection 563 between the first end 560 and the first end member 564 is a releasable threaded connection. To install the tie rods 532 in the appropriate position, each tie rod 532 having a second end member 568 thereon is inserted into the second module housing member 502b through a tie rod hole 570. The tie rods 532 pass through the tie rod holes 572 in the cell holder plate 508 and are threaded along the gap spaces 574 between the cells 503 (see also FIG. 5 ). Fig. 16B ) through. The pull rod 532 passes through the pull rod hole 572 in the first module housing member 502a until the first end 560 enters the first end member 564. The second end member 568 includes a tool receiving feature 576, such as a hexagonal hole for receiving a tool (not shown) such as a hexagonal drill. The tool can be rotated to rotate the second end member 568 until the second end member pushes the second module housing member 502b downward. As the tool is further rotated, all positive bus bar terminals 554 and negative bus bar terminals 552 engage with the corresponding positive cell terminals 524 and negative cell terminals 526 of the corresponding battery cells 503. The battery cell biasing member 536 applies a resistance biasing force on the battery cell 503. Finally, as the tool is further rotated, the engagement of the positive bus bar terminals 554 and the negative bus bar terminals 552 with the positive cell terminals 524 and the negative cell terminals 526 is strong enough that all battery cell biasing members 536 apply a resistance biasing force exceeding the selection threshold. This in turn causes an increase in the torque required to further rotate the second end member 568. A torque sensor may be provided for sensing when the torque required to rotate the tool exceeds a selected torque threshold, at which point the tool may be stopped and removed from the second end member 568. Stopping of the tool may occur automatically via a controller, or manually upon notification to the fitter.

[0113] In another embodiment, the tie rod 532 can be permanently mounted to the first end member 564, and thus can be permanently retained in the first module housing member 502a. In such an embodiment, the second module housing member 502b is placed on top of the first module housing member 502a, so that the tie rod 532 extends through the tie rod hole 572 in the second module housing member 502b. At this point, the second end member 568 can be mounted to the second end 562 of the tie rod 532 and can be tightened down (i.e., rotated) as described above until the torque required to tighten the second end member 568 down exceeds the aforementioned selected torque threshold.

[0114] The second end member sealing member 578 may be disposed between the second end member 568 and the second module housing member 502 b to prevent the cooling fluid from leaking out of the tie rod hole 572 .

[0115] Once the tie rod 532 is tightened down to the selected torque, it will be appreciated that the bus bar 528 proximate the tie rod 532 abuts against the highest cell 503 proximate the tie rod 532 with a selected force. Since the cell biasing member 536 is configured to apply a relatively constant force over a range of distances equal to the tolerance range of the cells 503, all of the cells 503 will contact the bus bar 528 with approximately the same force. This provides a more consistent amount of contact resistance between the cells 503 across the module 22 as compared to some prior art modules, without having to rely on inserting a tie rod into every single gap space 574 between all of the cells 503.

[0116] The tie rods 532 can have a relatively small cross-sectional area because they are in tension. For example, in some embodiments, the tie rods 532 can be cylindrical, and in some embodiments can have a diameter of about 3 mm or even 2 mm. It will be noted that by having a small diameter for the tie rods, the cells 503 can be nested in an offset pattern so as to have a high packing density. As is well known, cylinders are not packed too tightly when arranged in uniform rows and columns, and when arranged in an offset pattern (i.e., in a pattern such as Fig. 16B However, in some battery packs of the prior art, large components extend in the gap spaces between the cells and will not allow the cells to be arranged in an offset pattern. However, in the module currently shown, the cells 503 are arranged in an offset pattern, which reduces the size of the gap spaces 574 between the cells 503 compared to the linearly arranged cells arranged in rows and columns. However, the pull rods 532 shown are easily assembled in the smaller gap spaces 574 provided by the offset pattern without the risk of contacting the cells 503. In addition, the immersion cooling of the cells 503 provided by the currently described embodiment allows the cells 503 to be temperature controlled to a suitable degree despite the high packaging density of the cells 503.

[0117] Textured contact surface of busbars

[0118] Reference Fig. 9 and Fig.10 , Fig. 9 and Fig.10 The bottom sides of negative busbar terminal 552 and positive busbar terminal 554 are shown, respectively. Negative busbar terminal 552 and positive busbar terminal 554 both define contact surfaces 124 and 126, respectively, for contacting the negative terminal and the positive terminal of cell 503, respectively. For scale reference, in the illustrated embodiment, the arcuate contact surface 124 of negative busbar terminal 552 has an outer diameter of approximately 21 millimeters and an inner diameter of approximately 16 millimeters. The substantially circular contact surface 126 of the positive busbar terminal has a diameter of approximately 8 millimeters.

[0119] Reference Fig.11 , Fig.11 A side view of the contact surface 124 of the negative busbar terminal 552 or the contact surface 126 of the positive busbar terminal 554 is shown, respectively. The contact surface 124 or 126 defines a plurality of recesses 128 in the form of a V-shaped groove, the plurality of recesses 128 having: a vertical depth d, which may be any suitable value, such as about 0.3 mm; a second (e.g., maximum) horizontal width w-max, which may be any suitable value, such as about 0.3 mm; a first (e.g., minimum) horizontal width w-min, which may be any suitable value, such as about 0.1 mm; and a horizontal spacing s as measured between the tips of adjacent recesses 128, which may be any suitable value, such as about 1.0 mm. The depth d and minimum width w-min of the recesses 128 are selected so that the recesses 128 can accommodate small-scale contaminant particles, such as human hair, dust, or atomized paint spots. For reference, the average human hair has a diameter of about 0.12 mm. When received in the recess 128, the contaminant particles will not prevent electrical contact between the contact surface portions 130a and 130b and the terminals of the battery cell 503. Fig. 9 and Fig.10 In the illustrated embodiment, the V-groove recesses 128 extend in mutually perpendicular directions so as to define square contact surface portions 130a and 130b of the contact surface 124 or 126. Thus, the contact surface 124 or 126 is textured to have a tack-like pattern. Fig.11In the illustrated embodiment, the edges 132 of the contact surface portions 130a and 130b may form sharp corners rather than smooth or gradually rounded corners. The sharpness of the edge 128 may be selected so that when a contaminant particle, such as human hair, trapped between the contact surface 124 or 126 and the surface of the cell terminal is subjected to sufficient pressure between the contact surface 124 or 126 and the terminal of the cell 503, the edge 128 acts like a knife edge to cut off the contaminant particle.

[0120] In other words and more generally, the contact surface 124 or 126 is textured to define contact surface portions 130a and 130b that are horizontally connected by a vertical recess 128. The recess 128 can have various forms, wherein a non-limiting example is an elongated groove or a depression or a combination thereof. The recess 128 can be formed in various ways, such as by molding, etching, pressing or machining. The recess 128 has a vertical depth d of at least 0.2 mm and more particularly at least 0.3 mm measured from the contact surface portions 130a and 130b. As a non-limiting example, the depth d of the recess 128 can be in the range of 0.2 mm to 0.5 mm and its sub-range. The recess 128 can have a width w of at least 0.2 mm and more particularly at least 0.3 mm. As a non-limiting example, the minimum width w-min can be in the range of 0.2 mm to 0.5 mm and its sub-range.

[0121] Individual modules across the width of the battery pack & connections of modules in the battery pack

[0122] Reference Figure 4 , Figure 4 Schematic depiction of the electrical connections of the module 22 of the battery pack 10 is shown. The battery pack 10 has a Figure 1 ) of a circuit (not shown). It is desirable that the negative battery terminal 108 and the positive battery terminal 110 are positioned at a single end of the battery housing 20 to facilitate connection to a portion of the circuit, such as a battery disconnect unit (BDU) 112 of the electric vehicle 11.

[0123] As previously described, in the illustrated embodiment, the battery pack 10 has eight modules 22, represented as 22a to 22h. Each module 22 has a module housing 502 containing a first plurality of cells 503-544 and a second plurality of cells 503-546, each of which is connected to a corresponding first module terminal 534a and a second module terminal 534b. When each module 22 is considered individually, the first plurality of cells 503-544 and the second plurality of cells 503-546 are not electrically connected. However, in the entire battery pack 10, they are electrically connected to each other indirectly (for modules 22a to 22g) or directly (for module 22h), so that a common negative battery terminal 108 and a positive battery terminal 110 can be used to allow current to flow through the plurality of cells.

[0124] The first module end terminal 534a(a-1) of the first plurality of battery cells 503-544a of the first module 22a is connected to the negative battery terminal 108 or forms the negative battery terminal 108. The second module end terminal 534b(a-2) of the second plurality of battery cells 503-546a of the first module 22a is connected to the positive battery terminal 110 or forms the positive battery terminal 110.

[0125] The second module end terminals 534b(a-1) of the first plurality of cells 503-544a of the first module 22a are connected to the first module end terminals 534a(b-1) of the first plurality of cells 503-544b of the second module 22b. The first plurality of cells 503-544 of each subsequent module 22 are connected to the consecutive modules 22 up to and including the eighth module 22h in a similar manner.

[0126] The second module end terminals 534b(h-1) of the first plurality of battery cells 503-544h of the eighth module 22h are connected to the first module end terminals 534a(h-2) of the second plurality of battery cells 503-544b of the eighth module 22b.

[0127] The second module end terminals 534b(h-1) of the second plurality of cells 503-546h of the eighth module 22h are connected to the first module end terminals 534a(g-2) of the second plurality of cells 503-546g of the seventh module 22g. The second plurality of cells 503-546 of each preceding module 22 are connected to the preceding module up to and including the first module 22a in a similar manner.

[0128] In other words and more generally, the battery pack 10 has a battery housing 20 containing a plurality of modules 22 arranged in a row in the longitudinal direction of the battery pack 10. Each module 22a has a module housing 502 extending in the transverse direction of the battery pack 10 between the side walls 100 of the battery housing 22. Each module housing 502 contains a first plurality of battery cells 503-544 and a second plurality of battery cells 503-546 arranged side by side in the transverse direction of the battery pack 10.

[0129] For each module 22 considered individually, the cells 503 in the first plurality of cells 503-544 are electrically connected to each other; and the cells 503 in the second plurality of cells 503-546 are electrically connected to each other. However, when the cells are considered individually (i.e., before forming part of the battery pack 10), the second plurality of cells 503-546 are electrically isolated from the first plurality of cells 503-544. For each module 22, the first plurality of cells 503-544 are connected to the first module end terminal 534a(1) and the second module end terminal 534b(1). For each module 22, the second plurality of cells 503-546 are connected to the first module end terminal 534a(2) and the second module end terminal 534b(2).

[0130] In the battery pack 10, the modules 22 are electrically connected together. The first module end terminal 534a(1) of the first plurality of cells 503-544 of the first module 22 in the row is connected to or forms the battery pack terminal 108. The second end terminal module 534b(2) of the second plurality of cells 503-546 of the first module 22 in the row is connected to or forms another battery pack terminal 110.

[0131] The first plurality of cells 503 544 of the modules 22 are connected in series between the consecutive modules 22 in the row via the module first end terminals 534a(1) and the second end terminals 534b(1) to form a group of the first plurality of cells 503 544 connected in series. The second plurality of cells 503 546 of the modules 22 are connected in series between the consecutive modules 22 in the row via the module end terminals 534a(2) and 534b(2) to form a group of the second plurality of cells 503 546 connected in series. Since the first plurality of cells 544 503 in the last module 22 of the row are connected in series with the second plurality of cells 503 546 of the same last module 22 of the row via the second module end terminals 534b(1) of the first plurality of cells 544 and the first module end terminals 534a(2) of the second plurality of cells 503 546, the group of the first plurality of cells 503 544 is connected in series with the group of the second plurality of cells 503 546. Thus, except for the last module 22 of the row, the first plurality of cells 503 544 and the second plurality of cells 503 546 within each module 20 are not directly connected to each other.

[0132] The battery pack terminals 108 and 110 are positioned at one end of the battery pack 10. Thus, the circuit paths of the first plurality 544 and the second plurality 546 of the modules 22 collectively have a U-shaped configuration within the plane containing the row of modules 22. However, structurally, the first plurality 544 and the second plurality 546 of each module 22 are contained in a single housing 502. This improves upon the conventional configuration of two physically discrete side-by-side module rows that results in structural weaknesses between the module rows. In embodiments where the module housing 502 is contained within and engaged with a common battery pack housing 20 (e.g., by connection to the battery pack housing 20 and / or by compression between the bottom battery pack housing member 20a and the top battery pack housing member 20b), the module housing 502 can also effectively reinforce the battery pack housing 20, and strengthen the battery pack 10 and enhance its rigidity.

[0133] Voltage tap through case

[0134] Reference Fig.12 and Fig.25 In this embodiment, if Fig.12As shown, the module control system 700 includes two module controllers 702, each of which is dedicated to one of the plurality of cells 503, 544, and 546, and each of which communicates with the battery pack control system 26. The module controllers 702 each include a processor 704 and a memory 706 storing program code for execution by the processor 704. The program code can be used to transmit temperature data related to the module 22 to the battery pack control system 26. For example, the data can be sensor data from one or more temperature sensors (not shown) that sense the temperature of the cooling fluid entering and / or leaving and / or at a selected position in the module 22. The data can be sensor data from a plurality of voltage taps 530.

[0135] Multiple voltage taps 530 ( Fig.25 ) is a conductive member extending through the module housing 502, and each of the voltage taps 530 has: a first end 580, which is connected to the bus bar 528 ( Fig.21 ) in which the busbar voltage tap receiving hole shown at 582 is press-fitted; and a second end 584, which is received in a press-fitted engagement with the controller voltage tap receiving hole shown at 586.

[0136] In the illustrated embodiment, the clamping member 550 present for retaining the bus bar 528 is located at the first end 580 of the voltage tap 530, and the bus bar voltage tap receiving aperture 582 is the clamping aperture 549 in the bus bar 528. Thus, the voltage tap 530 helps retain the bus bar 528 in place on the second module housing member 502b.

[0137] The voltage taps 530 may be molded directly into the second module housing member 502b. Thus, each voltage tap 530 need not include a separate sealing member. There may be a voltage tap provided for each bus bar present in the module 22.

[0138] Modules connected in parallel via cooling fluid supply and return hoses accessible from the top

[0139] Reference Figures 5 to 7 , Figures 5 to 7 A view of a module 22 of a battery pack 10 is shown. In the illustrated embodiment, a first module housing member 502a has an upper surface to which eight tubular T-shaped barbed hose fittings 114a to 114h (generally 114) are attached. Four hose fittings 114a to 114d are associated with a first plurality of cells 503 to 544 of the module 22; and four hose fittings 114e to 114g are associated with a second plurality of cells 503 to 546 of the module 22. Fig.12, hose fittings 114a, 114b are connected to a first cooling fluid supply hose 116a; hose fittings 114c and 114d are connected to a first cooling fluid return hose 117a; hose fittings 114e and 114f are connected to a second cooling fluid supply hose 116b; and hose fittings 114g and 114h are connected to a second cooling fluid return hose 117b. Generally, each cooling fluid supply hose may be indicated by reference numeral 116, and each cooling fluid return hose may be indicated by reference numeral 117.

[0140] Reference Figure 6 , Figure 6 The cross-sectional view along the cross-sectional line AA intersecting the hose fitting 114a is shown. Figure 5 502a, so that the lumen of the hose fitting 114a is in fluid communication with the battery cell chamber 505. Although not shown, the central branches of the hose fittings 114b, 114e and 114f are similarly received within three other module housing cooling fluid inlets 118 defined by the upper surface of the first module housing member 502a. Thus, cooling fluid can be supplied from the first cooling fluid supply hoses 116a and 116b ( Fig.12 ) flows into the cell chamber 505 via the hose fittings 114a and 114b, and then the cooling fluid passes through the cooling fluid through-holes 514 ( Fig.18 ) to immerse the first plurality of cells 503-544 of the module 22. Similarly, the cooling fluid can be supplied from the second cooling fluid supply hose 116b ( Fig.12 ) flows into the cell chamber 505 via the hose fittings 114e and 114f to immerse the second plurality of cells 503 - 546 of the module 22.

[0141] Reference Figure 7 , Figure 7 A cross-sectional view along section line BB intersecting hose fittings 114c and 114d is shown. Figure 5502a and 502b and extend downwardly toward the second module housing member 502b, such that the lumen of each of the hose fittings 114c and 114d is in fluid communication with the battery cell chamber 505. Although not shown, the central branches of the hose fittings 114g and 114h are similarly received within two other module housing cooling fluid inlets 120 defined by the upper surface of the first module housing member 502a. Thus, cooling fluid can flow upward from the battery cell chamber 505, through the module housing cooling fluid outlets 120a and 120b and into the hose fittings 114c and 114d, respectively, and into the first cooling fluid return hose 117a. Similarly, cooling fluid may flow upward from the cell chamber 505, through the two other module housing cooling fluid outlets 120 and into hose fittings 114g and 114h, respectively, and into a second cooling fluid return hose 117b.

[0142] exist Figure 5 In the illustrated embodiment, the module housing 502 defines two module housing cooling fluid inlets 116 and two module housing cooling fluid inlets 117 for each of the first plurality of battery cells 503-544 and the second plurality of battery cells 503-546 of the module 22. In other embodiments, the module housing member 502 may define any other suitable number (i.e., one or more) of module housing cooling fluid inlets 116 and module housing cooling fluid inlets, which may be selected taking into account factors such as the shape and size of the battery cell chamber 505, the flow rate of the cooling fluid to be supplied to the battery cell chamber 505, the expected heat output of the battery cell 503, and the desired cooling performance.

[0143] exist Figure 5 In the illustrated embodiment, the module housing 502 defines a module housing cooling fluid inlet 118 that is relatively close to the module housing cooling fluid inlet 118.

[0144] The partition wall 548 ( Fig.15 ) and relatively horizontally away from the side wall 104 of the module housing 502 ( Fig.12 ). In contrast, the module housing 502 defines a module housing cooling fluid outlet 120 that is relatively horizontally proximate to the side wall 104 of the module housing 502 and relatively horizontally distal to the partition wall 548 of the module 22 ( Fig.15). This arrangement of the module housing cooling fluid inlet 118 and the module housing cooling fluid outlet 120 causes the cooling fluid to flow downwardly through the battery cell chamber 505 as a whole, and to flow horizontally through the battery cell chamber 505 in the lateral direction toward the side wall 104 of the module housing 502. In other embodiments, the module housing cooling fluid inlet 118 and the module housing cooling fluid outlet 120 may have different arrangements to achieve different patterns of cooling fluid flowing through the battery cell chamber 505.

[0145] Reference Figure 8 , Figure 8 A schematic depiction of a cooling fluid supply hose 116 and a cooling fluid return hose 117 associated with eight modules 22a to 22h of a battery pack 10 is shown. When in use, the cooling fluid supply hoses 116a and 116b and the cooling fluid return hoses 117a and 117b are in fluid communication with a cooling fluid source 122. As a non-limiting example, the cooling fluid source 122 can be part of a cooling fluid circuit of a thermal management system (not shown) of an electric vehicle 11, which includes components such as a reservoir, a pump, a valve, and a heat exchanger. The cooling fluid flows from the cooling fluid source 122 into the cell chamber 503 of the modules 22a to 22h via the cooling fluid supply hoses 116a and 116b and the module housing cooling fluid inlet 118. Thus, the cooling fluid source 122 supplies the cooling fluid to the modules 22a to 22h in parallel with each other. The cooling fluid flows through the cell chamber 505 to absorb heat from the cells 503 therein. The heated cooling fluid then flows from the cell chambers 505 of modules 22a-22h via module housing cooling fluid outlets 120 and cooling fluid return hoses 117a and 117b back to cooling fluid source 112. Thus, modules 22a-22h return cooling fluid to cooling fluid source 122 in parallel.

[0146] In other words and more generally, the battery pack 10 has a battery pack housing 20 that includes a plurality of modules 22. Each module 22 has a module housing 502 that defines a cell chamber 505 that includes a plurality of cells. The module housing 502 has an upper surface that defines at least one module housing cooling fluid inlet 118 in fluid communication with the cell chamber 505 and at least one module housing cooling fluid outlet 120 in fluid communication with the cell chamber 505. Since the module housing cooling fluid inlet 118 and the at least one module housing cooling fluid outlet 120 are defined by the upper surface of the module housing 502, the inlet and outlet are conveniently accessible via the top side of the module 22. The cooling fluid supply hose 116 is in fluid communication with the module housing cooling fluid inlet 118 of two or more modules 22 to allow cooling fluid to be supplied from a cooling fluid source 122 to the cell chambers 505 of the two or more modules 22 in parallel. The cooling fluid return hose 117 is in fluid communication with the module housing cooling fluid outlets 120 of the two or more modules 22 to allow cooling fluid to flow back in parallel from the cell chambers 505 of the two or more modules 22 to the cooling fluid source 122 .

[0147] Charging, use and handling of battery packs

[0148] The power of the charging source can be increased by increasing the voltage and / or current of the charging source, thereby reducing the charging time of the battery cell 503. Similarly, the power output of the battery cell 503 can be increased by increasing the discharge rate of the battery cell 503. However, increases in charging and discharging rates are associated with increases in the heat generated by the battery cell 503, which has a deleterious effect on battery life, physical degradation, and safety considerations. Therefore, as a compromise to maintain battery life, the charging rate and the discharge rate are typically adjusted. For example, in electric vehicle applications, the peak C-rate is typically limited to about 3.0C, and the average C-rate over the range of charge states is typically limited to about 1.0C to 2.0C. (A C-rate is a measure of the rate at which a battery can be charged or discharged relative to its maximum capacity. For example, a C-rate of 1C means the battery pack will be fully charged or discharged in one hour, while a C-rate of 3C means the battery pack will be fully charged or discharged in twenty minutes.) In addition, the depth of charge (DoC) and depth of discharge (DoD) of the battery pack are also typically limited to a range greater than 80% and less than 100% to preserve battery life. (DoC or DoD refers to the percentage of the battery pack capacity to which the battery pack is charged or discharged, respectively.)

[0149] The battery pack 10 as described can be an immersion cooled battery pack. That is, the battery cells 503 within the battery cell chambers 505 of the modules 22 can be in direct contact with the liquid cooling fluid in the battery cell chambers 503 so as to transfer heat from the battery cells 503 to the cooling fluid conductively. Compared to air cooling or indirect liquid cooling (e.g., using a heat exchanger carrying a heat exchanger medium), immersion cooling can be advantageous in terms of heat transfer efficiency and thermal control of the battery cells 503.

[0150] The battery pack 10 as described can have cells 503 that are removable from the module housing 502. This is because the cell biasing member 536 can be configured to apply sufficient biasing force to the cell 503 to maintain electrical contact between the positive cell terminal 524 and the positive bus bar terminal 554 and between the negative cell terminal 526 and the negative bus bar terminal 552 under expected operating conditions. This avoids the need to weld the positive cell terminal 524 and the negative cell terminal 526 to the positive bus bar terminal 554 and the negative bus bar terminal 552, respectively. Therefore, if the performance of the cell 503 deteriorates to an unsatisfactory level or if they are damaged, the cell 503 can be easily replaced.

[0151] The combination of a battery pack 10 with immersion cooled cells 503 and removability of cells 503 enables the battery pack 10 to be charged and discharged at higher C rates and used at higher DoC and higher DoD. This is because immersion cooling allows for more effective thermal control of the cells 503, and the removability of the cells 503 allows for more convenient sacrificial replacement of poorly performing or damaged cells 503 with new cells 503 during the life cycle of the battery pack 10.

[0152] Optional layout for multi-group systems

[0153] Reference Fig.26 , Fig.26 An example layout of a multi-group system 600 including a plurality of battery packs 10 and a thermal management system 602 for the plurality of battery packs 10 is shown. The plurality of battery packs include a first battery pack 10a, a second battery pack 10b, a third battery pack 10c, and a fourth battery pack 10d. The number of battery packs 10 included in the multi-group system 600 shown here is for example only. The multi-group system 600 may include as few as two battery packs 10, three battery packs 10, five battery packs 10, or more (i.e., as many battery packs 10 as required for a particular application). Therefore, it can be said that the multi-group system 600 includes a first battery pack 10a and a second battery pack 10b, and may optionally include more battery packs 10.

[0154] Fig.26 Each battery pack 10 shown in FIG. 1 (thus including each of the first battery pack 10 a and the second battery pack 10 b ) may be similar to Figures 2 to 25 The battery pack 10 is shown in FIG.

[0155] The thermal management system 602 may include a coolant system 604 that delivers a coolant through the plurality of battery packs 10, and may also include a refrigerant system 606 that delivers a refrigerant for cooling the coolant. Fig.26 In the example shown, the coolant 605 is a cooling fluid in which the battery cell 503 is immersed. The coolant system 604 may include a radiator 608, a heater 610, a cooler 612, a heat storage tank 613, a plurality of valves 614, a degassing tank 615, and at least one pump 616. The refrigerant system 606 may include a compressor 617, a condenser 618 (and its associated fan) and an expansion valve 619, and passes the refrigerant through the cooler 612 to act as an evaporator. Therefore, the cooler 612 exchanges heat between the coolant and the refrigerant.

[0156] Radiator 608 may be any suitable radiator known for use in electric vehicles and non-electric (e.g., gasoline engine-driven) vehicles, and include a fan to assist in blowing air through the radiator body, thereby facilitating cooling of the coolant contained in the radiator body, as is known in the art. Heater 610 may be any suitable type of heater, such as, for example, an electric heater. For example, heater 610 may be a PTC heater or any other suitable type of heater.

[0157] The thermal storage tank 613 may be a tank containing a secondary cooling medium 613a, which is a medium used to reduce the temperature of the coolant in selected emergency situations (e.g., when there is a risk of thermal runaway in one or more of the battery packs 10). The secondary cooling medium 613a may be any suitable medium, such as a suitable phase change material that can cool the coolant even after the coolant has been cooled using the refrigerant system 606. Examples of suitable secondary cooling media 613a will be known to those skilled in the art and will depend on the particular application.

[0158] In the example shown, the plurality of valves 614 include a first coolant valve 614a, a second coolant valve 614b, a third coolant valve 614c, a fourth coolant valve 614d, a fifth coolant valve 614e, a sixth coolant valve 614f, a seventh coolant valve 614g, an eighth coolant valve 614h, a ninth coolant valve 614i, and a tenth coolant valve 614j. The coolant valve 614 may have any suitable structure. The coolant valves 614a to 614f may all be remotely controlled valves, which may be two-position valves (movable to only an open position and a closed position), multi-position valves (valves that can be moved to multiple positions including an open position, a closed position, and at least one partially open position), and infinitely adjustable valves (which can be infinitely adjusted between an open position and a closed position). Providing remotely controlled valves for the coolant valves 614a to 614f allows the control system (shown as 620) for the thermal management system 602 to control which battery packs in the battery pack 10 receive coolant and which battery packs do not receive coolant. Providing the coolant valves 614 a - 614 f with infinitely adjustable remote control valves or multi-position remote control valves allows the control system 620 to control a non-zero flow amount of coolant provided to each battery pack 10 individually based on the cooling requirements of each battery pack 10 .

[0159] Coolant valves 614g to 614i may all be remote controlled valves, which may be two-position, multi-position, or infinitely adjustable. Coolant valve 614j may be a remote controlled three-way valve (one inlet, two outlets), which may be two-position, multi-position, or infinitely adjustable. Coolant valve 614j allows control system 620 to select whether to deliver coolant to thermal storage tank 613 or to deliver coolant toward battery pack 10 while bypassing thermal storage tank 613.

[0160] It will be noted that the lines shown as solid lines in coolant system 604 and refrigerant system 606 are lines containing coolant flow or refrigerant flow (as the case may be). In addition, coolant valves 622g, 622h and 622i are shown as filled in black when they are closed, and filled in white when they are open to allow coolant to flow therethrough.

[0161] Control systems and operations

[0162] The control system 620 controls the operation of the thermal management system 602 and may be separate from or integrated or partially integrated with another control system for the battery pack 10. The control system 620 includes a processor 620a and a memory 620b, and receives signals from a sensor arrangement 621. The sensor arrangement 622 includes at least one sensor for each battery pack in the battery pack 10, which sends a signal to the control system 620 indicating whether any of the cells in any of the battery packs in the battery pack is at risk of thermal runaway. In the example embodiment shown, the at least one sensor includes a plurality of temperature sensors 622. The temperature sensors 622 may include temperature sensors 622a, 622b, 622c, 622d, 622e, 622f, 622g, 622h, 622i, 622j, 622k, and 622I. The first temperature sensor 622a, the second temperature sensor 622b, the third temperature sensor 622c, and the fourth temperature sensor 622d are positioned to send a signal indicating the temperature of each of the plurality of battery packs 10 (and thus the temperature of the first battery pack 10a and the second battery pack 10b) to the control system 620. The temperature sensor 622k may be referred to as a secondary cooling medium temperature sensor, which is positioned to send a signal indicating the temperature of the secondary cooling medium 613a to the control system 620.

[0163] As an alternative or in addition to any other sensor described as part of the sensor arrangement, the sensor arrangement may include Fig. 27 , which are schematically shown in the figure, and are internal to each of the battery packs 10 and some of which are generally shown as 624 and individually as 624a, 624b, 624c and 624d. These temperature sensors 624 are also positioned to send a signal indicating the temperature of each of the multiple battery packs 10 (and therefore the temperature of the first battery pack 10a and the second battery pack 10b) to the control system 620, and can be positioned closer to the battery cell 503 at risk of thermal runaway than the temperature sensor 622. Fig. 27 As schematically shown in FIG. 6 , a temperature sensor 624 inside each battery pack can communicate with the battery pack control system 26 for that battery pack 10 , and each battery pack control system 26 can then communicate with the control system 620 .

[0164] As an alternative or in addition to any other sensors described as part of the sensor arrangement, the sensor arrangement may include a plurality of voltage sensors 626 that may send signals to the control system 620 and that are indicative of, among other things, the cooling load represented by each of the battery packs 10. The voltage sensors 626 are individually illustrated as a first voltage sensor 626a for the first battery pack 10a, a second voltage sensor 626b for the second battery pack 10b, a third voltage sensor 626c for the third battery pack 10c, and a fourth voltage sensor 626d for the fourth battery pack 10d. It will be noted that the signals from the temperature sensors 622a to 622d are also indicative of the thermal load represented by each of the battery packs 10. As an alternative or in addition to any other sensors described as part of the sensor arrangement, the sensor arrangement may include Fig. 27 1, and a plurality of voltage sensors are schematically shown in the figure, the plurality of voltage sensors are internal to each of the battery packs 10 and some of the plurality of voltage sensors are generally shown at 628 and individually shown at 628a, 628b, 628c and 628d. The voltage sensor 628 may be incorporated into the voltage tap 530 shown in other figures. In general, it can be said that the signal indicating the thermal load represented by the battery pack 10 indicates a cooling load indication value for the battery pack 10.

[0165] The sensor arrangement may also include a plurality of flow sensors 630 , and are shown individually as a first flow sensor 630 a and a second flow sensor 630 b . Note also that there may be a separate flow sensor 630 for each battery pack 10 .

[0166] Fig. 27 The control system 620 and its connections to the various sensors described herein are shown schematically.

[0167] Reference Figure 26 to Figure 35 The sensors depicted do not have connecting lines drawn back to the control system 620 (except Fig. 27 ) so as not to visually clutter the drawing. However, it will be understood that the sensors may communicate with the control system 620 in any suitable manner, such as by cable, wirelessly, or by any other suitable means.

[0168] The memory 620b contains program code executable by the processor 620a to perform the following operations: based on the signal, operate the plurality of valves 622 to increase the flow of cooling fluid (in this example, coolant) to one of the battery packs 10 and reduce the flow of cooling fluid (in this example, coolant) to the other battery packs 10 so as to suppress thermal runaway in the one of the battery packs 10. Reducing the flow of cooling fluid to any battery pack 10 is intended to include stopping the flow of coolant to the battery pack 10.

[0169] By reducing the flow of cooling fluid (e.g., coolant) to other battery packs 10, the thermal management system 602 is able to increase the flow of cooling fluid to battery packs 10 determined to be at risk of thermal runaway, and may also be able to provide a cooler temperature for the cooling fluid entering the battery pack 10 determined to be at risk of thermal runaway, thereby better suppressing the occurrence of thermal runaway and its spread throughout the battery pack 10 determined to be at risk.

[0170] As shown in FIG. 6 , the thermal management system 602 in the heating mode Fig.32 As shown, in a specific example, the memory contains program code that can be executed by the processor to perform the following operations:

[0171] a) determining whether the first battery pack 10a is at risk of thermal runaway based on the signal;

[0172] b) determining whether the second battery pack 10 b is at risk of thermal runaway based on the signal;

[0173] c) based on determining in steps a) and b) that the first battery pack 10a is at risk of thermal runaway and the second battery pack 10b is not at risk of thermal runaway, operating the plurality of valves 622 to increase the flow of cooling fluid to the first battery pack 10a and to reduce the flow of cooling fluid to the second battery pack 10b; and

[0174] d) based on determining in steps a) and b) that the first battery pack 10a is at risk of thermal runaway and the second battery pack 10b is not at risk of thermal runaway, operating multiple valves to increase the flow of cooling fluid to the first battery pack 10a and reduce the flow of cooling fluid to the second battery pack 10b.

[0175] For example, in an embodiment where the temperature sensor 622a sends the following signal, the processor 620a can determine that the first battery pack 10a is at risk of thermal runaway, and the signal indicates that the temperature of the coolant in the first battery pack 10a is increasing at at least a selected rate or has increased to a temperature that is greater than a selected delta (incremental) temperature that is higher than the temperature of the other battery packs 10.

[0176] In contrast, the processor 620a can determine that the first battery pack 10a is not at risk of thermal runaway if the temperature sensor 622a sends the following signal, which shows that the temperature of the coolant in the first battery pack 10a does not increase or only increases synchronously with the temperatures of the other battery packs 10, so that the temperature of the first battery pack 10a is within a selected delta (incremental) temperature of the temperatures of the other battery packs 10.

[0177] When coolant is sent to any battery pack determined to be at risk of thermal runaway, the control system 620 can operate the refrigerant system 606 in a known manner for refrigerant systems (i.e., compressing the refrigerant in the compressor 617, condensing the refrigerant in the condenser 618, expanding the refrigerant in the expansion valve 619, and evaporating the refrigerant in the cooler 612) so as to use the refrigerant to cool the coolant flowing through the cooler 612 and direct the coolant to flow through the cooler 612 and then to any battery pack 10 that is at risk of thermal runaway.

[0178] The memory 620b may include program code executable by the processor during steps c) and d) to perform the following operations:

[0179] e) operating the refrigerant system to cool the refrigerant, and

[0180] f) controlling a plurality of valves to direct the coolant through the cooler 612 so that the coolant is cooled by the refrigerant in the cooler 612, thereby providing the coolant with a lower temperature than would be provided using the radiator 608, thereby enhancing the effectiveness of the coolant in suppressing thermal runaway.

[0181] In an embodiment where the thermal management system 602 includes a thermal storage tank, the memory 620b may include program code executable by the processor during steps c) and d) to perform the following operations:

[0182] g) controlling a plurality of valves to direct the coolant through the thermal storage tank, thereby cooling the coolant by the secondary cooling medium.

[0183] like Fig.28 As shown, Fig.28 The thermal management system 602 is shown in a heating mode. The memory 620b may also contain program code executable by the processor 620a to perform the following operations:

[0184] h) determining, based on the signal, whether a temperature of at least one of the first battery pack and the second battery pack 10 is less than a first threshold battery pack temperature; and

[0185] i) Based on the determination in step h), control a plurality of valves to direct coolant through the heater to heat at least one of the battery packs 10 (or in an embodiment, one of the first battery pack 10a and the second battery pack 10b) so that the temperature of at least one of the first battery pack 10a and the second battery pack 10b is above a first threshold battery pack temperature and within a selected operating temperature range of at least one of the first battery pack 10a and the second battery pack 10b. The first threshold battery pack temperature may be any suitable temperature, such as, for example, 20 degrees Celsius.

[0186] As shown, thermal management system 602 in passive cooling mode Fig.29 As shown, in an embodiment where a plurality of temperature sensors 622 (i.e., including temperature sensor 622I as an ambient temperature sensor) are positioned to send a signal indicating the ambient temperature to the control system, the memory 620 may also include program code executable by the processor 620a to perform the following operations:

[0187] j) determining, based on the signal, whether the ambient temperature is less than a first threshold ambient temperature;

[0188] k) determining whether a cooling load indication value for at least the first battery group and the second battery group (10a and 10b) is below a selected cooling load indication value; and

[0189] l) Based on the determinations in steps j) and k), controlling the plurality of valves 614 to direct coolant through the radiator 608 to maintain at least the first battery pack 10a and the second battery pack 10b below a selected upper threshold battery pack temperature.

[0190] The selected upper threshold battery pack temperature may be any suitable temperature, such as, for example, about 60 degrees Celsius. The selected cooling load indication value may depend on a number of factors, such as the capacity of the radiator, the sensed ambient temperature, the flow of the coolant system 604, and other factors, and may be selected based on the requirements of the application. The first threshold ambient temperature may be any suitable value, such as, for example, 35 degrees Celsius.

[0191] As shown, thermal management system 602 in active cooling mode Fig.30 As shown, in an embodiment where a plurality of temperature sensors 622 (i.e., including temperature sensor 622I as an ambient temperature sensor) are positioned to send a signal indicating the ambient temperature to the control system, the memory 620 may also include program code executable by the processor 620a to perform the following operations:

[0192] m) determining, based on the signal, whether the ambient temperature is above a first threshold ambient temperature and / or whether the cooling load indication value for at least the first battery pack 10a and the second battery pack 10b is above a selected cooling load indication value; and

[0193] n) based on a determination in step m) as to whether an ambient temperature is above a first threshold ambient temperature and / or a determination that a cooling load indication value for at least the first battery pack 10a and the second battery pack 10b is above a selected cooling load indication value, operate the refrigerant system 606 and control a plurality of valves 614 to direct coolant through the cooler 612 to maintain at least the first battery pack 10a and the second battery pack 10b (or a plurality of battery packs 10) below a selected upper threshold battery pack temperature.

[0194] As shown, the thermal management system 602 in the secondary cooling medium charging mode Fig.31 As shown, in an embodiment where the sensor arrangement includes a secondary cooling medium temperature sensor 622k, the secondary cooling medium temperature sensor 622k is positioned to send a signal indicating the temperature of the secondary cooling medium 613a to the control system 620, and

[0195] The memory also includes program code that can be executed by the processor to perform the following operations:

[0196] m) determining, based on the signal, that a temperature of the secondary cooling medium is above a selected threshold temperature for the secondary cooling medium; and

[0197] n) based on the determination in step m) and based on the determination in steps a) and b) that the first battery pack is not at risk of thermal runaway and the second battery pack is not at risk of thermal runaway, operate the refrigerant system and control multiple valves to direct coolant through the cooler and through the secondary cooling tank to maintain at least the first battery pack and the second battery pack below a selected upper threshold battery pack temperature.

[0198] It will be noted that Fig.31 The valve opens and closes with Fig.32 The same valve as shown in .

[0199] Fig.33 The secondary cooling storage tank 613 is shown used in combination with the cooler 612 to cool the coolant during a situation in which the ambient temperature is determined to be very hot such that the cooler 612 will be unable to control the temperature of the battery pack 10 to below a second threshold battery pack temperature (e.g., 60 degrees Celsius), even if the control system 620 did not determine in steps a) and b) that there is a risk of thermal runaway in the first battery pack 10a and the second battery pack 10b (or alternatively in all battery packs 10).

[0200] Fig.34An embodiment is shown in which both the heater and the cooler are combined into a single unit, which is a heat pump shown at 640. An example of such a heat pump may be provided in PCT publication WO2023060352, the contents of which are fully incorporated herein by reference. It will be appreciated by those skilled in the art that, depending on the needs of the thermal management system 602, the heat pump 640 may cooperate with the refrigerant system 606 to heat or cool the coolant as needed.

[0201] Fig.35 Yet another embodiment is shown where both the heater and cooler are replaced by a heat exchanger shown at 642. The heat exchanger 642 is positioned to exchange heat with an external thermal management system shown at 644. The external thermal management system 644 may be any suitable type of thermal management system and may pre-exist prior to installation of the battery pack 10 and thermal management system 602. The external thermal management system 644 may be capable of heating and cooling the coolant in the heat exchanger 642 to temperature control the battery pack 10 as desired.

[0202] Additional Statement

[0203] It will be noted that the steps described herein as being contained within the program code stored in the memory 620b and executed by the processor 620a are identified with letters to facilitate easier reference to the steps, but the letters identifying the steps should not be interpreted as limiting the steps to be performed in the alphabetical order of the identifying letters. Thus, step b) need not be performed after step a). Furthermore, as will be apparent to one skilled in the art, some steps may be performed in an order different from that indicated by the alphabetical order.

[0204] In any case described herein where a memory contains program code executable by a processor to make one or more determinations and to perform an action based on the one or more determinations, it is intended to mean that the program code performs an action based only on the one or more determinations. In at least some cases, the program code may perform an action based on the one or more determinations and additionally based on one or more other determinations. For example, it has been noted above that the memory contains program code executable by the processor to perform the following operations: j) based on the signal, determining whether the ambient temperature is less than a first threshold ambient temperature; k) determining whether the cooling load indication value for at least the first battery pack and the second battery pack is lower than a selected cooling load indication value; and I) based on the determinations in steps j) and k), controlling multiple valves to direct coolant through the radiator 608 to keep at least the first battery pack and the second battery pack below a selected upper threshold battery pack temperature. It will be noted that the memory also performs step I) based on the determination that there is no risk of thermal runaway in steps a) and b).

[0205] Those skilled in the art will appreciate that the embodiments disclosed herein may be modified or adapted in various other ways while still remaining within the scope of the appended claims.

Claims

1. A module for a battery pack, comprising: A module housing and a plurality of battery cells, wherein the module housing comprises a first module housing member and a second module housing member, wherein the module housing defines a battery cell chamber for holding the plurality of battery cells and a quantity of cooling fluid, wherein the second module housing member has a plurality of tie rod holes passing through the second module housing member; a plurality of bus bars in the housing, the plurality of bus bars electrically connecting the cells in a combination of series electrical connection and parallel electrical connection; at least one cell biasing member positioned to urge the battery cell and the bus bar into engagement with each other with at least a selected engagement force; and a plurality of tie rods, wherein each tie rod from the plurality of tie rods has a first end and a second end, and wherein the first end has a first connection to a first end member engaged with the first modular housing member, and wherein the second end has a second connection to a second end member engaged with the second modular housing member such that the first end member and the second end member exert a selected clamping force on the first modular housing member and the second modular housing member, Wherein at least one of the first connection and the second connection is a threaded connection, so that the second end member can be rotated by a tool until a selected torque is reached, and the selected torque indicates that any of the plurality of battery cells close to the pull rod engage with each other with at least a selected engagement force.

2. A module for a battery pack, comprising: module housing; a plurality of battery cells positioned in the module housing, each of the battery cells comprising a positive terminal and a negative terminal; a bus bar electrically connecting positive terminals on cells from a first subset of the plurality of cells and negative terminals on cells from a second subset of the plurality of cells; a cell biasing member positioned to engage all of the cells of the first subset and one of the cells of the second subset separately from the bus bar and electrically connected in parallel to negative terminals of all of the cells of the first subset and one of the cells of the second subset, The cell biasing member urges all of the cells of one of the first subset of cells and the second subset of cells toward the bus bar.

3. A module for a battery pack, comprising: A module housing and a plurality of battery cells, wherein the module housing comprises a first module housing member and a second module housing member, wherein the module housing defines a battery cell chamber for holding the plurality of battery cells and a quantity of cooling fluid, wherein the second module housing member has a plurality of tie rod holes passing through the second module housing member; a plurality of bus bars in the housing, the plurality of bus bars electrically connecting the cells in a combination of series electrical connection and parallel electrical connection; at least one biasing member positioned to apply a biasing force to urge the battery cell and the bus bar into engagement with each other at at least a selected engagement force; and wherein the plurality of biasing members extend over a range of values ​​between a low height value and a high height value, wherein the low height value and the high height value are at least partially dependent on a tolerance of a cell height of the cell, and wherein the bias force varies between a low bias force at one of the low height value and the high height value and a high bias force at the other of the low height value and the high height value, And wherein a ratio of the low bias force to the high bias force is less than a ratio of the low height value to the high height value.

4. A module for a battery pack, comprising: a module housing defining a sealed fluid retaining space for retaining a quantity of cooling fluid; a plurality of battery cells positioned in the module housing, each of the battery cells comprising a positive terminal and a negative terminal; a bus bar in the fluid holding space, wherein the bus bar electrically connects positive terminals on cells from a first subset of the plurality of cells and negative terminals on cells from a second subset of the plurality of cells; a voltage tap engaged with the bus bar, wherein the voltage tap is molded into the housing; and A module controller is mounted to the exterior of the module housing, wherein the voltage tap engages the module controller to send a signal to the module controller.

5. A battery pack comprising: Battery pack housing; a plurality of modules positioned in the battery pack case and horizontally spaced apart, wherein each of the modules includes a module case defining a coolant holding space for holding a certain amount of coolant and a plurality of battery cells positioned in the module case; a coolant supply line in fluid communication with a coolant source and the coolant-retaining space of at least two of the modules; wherein the coolant supply line is in parallel fluid communication with the at least two of the modules; and The coolant supply line is contained in the battery pack housing, outside the module housing, and connected to the top sides of the module housings of the at least two modules.

6. A battery pack comprising: a battery pack housing defining a pair of side walls; as well as a plurality of modules positioned in the battery pack housing in rows along the side walls, wherein each of the modules includes a module housing extending between the side walls; Each of the modules includes a first plurality of battery cells that are all electrically connected to each other, and a second plurality of battery cells that are all electrically connected to each other and electrically isolated from the first plurality of battery cells.

7. A battery pack comprising: Battery pack housing; a plurality of modules positioned in the battery pack housing, wherein each of the modules includes a module housing defining a cell chamber containing a plurality of battery cells and having an upper surface defining at least one module housing cooling fluid inlet; a coolant supply hose in parallel fluid communication with a cooling fluid source and module housing cooling fluid inlets of at least two of the modules; and The coolant supply hose is contained in the battery pack housing and is outside the module housing.

8. A bus bar for a battery module including a battery cell having a battery cell terminal, the bus bar comprising: A contact surface for contacting the battery cell terminal, wherein the contact surface is textured to define a plurality of contact surface portions, and a plurality of recesses between adjacent contact surface portions in the contact surface portions, wherein the recesses have a depth of at least 0.2 mm and a width of at least 0.2 mm from the contact surface portions.

9. A battery pack system for an electric vehicle, comprising: a plurality of battery packs, wherein each battery pack includes a plurality of battery cells for storing an electrical charge for powering a traction motor of the electric vehicle; a thermal management system for the plurality of battery packs, the thermal management system delivering a cooling fluid through the battery packs; a plurality of valves controlling the flow of the cooling fluid to each of the battery packs; a control system operably connected to the valve to control operation of the valve to control flow of the cooling fluid to each of the battery packs; at least one sensor in each of the battery packs, the at least one sensor sending a signal to the control system, wherein the signal indicates whether any of the battery cells in any of the battery packs is at risk of thermal runaway; The control system includes a processor and a memory, wherein the memory contains program code that can be executed to perform the following operations: based on the signal, operating the multiple valves to increase the flow of the cooling fluid to one of the battery packs and reduce the flow of the cooling fluid to other battery packs so as to suppress thermal runaway.

10. A battery pack system for an electric vehicle, comprising: a first battery pack and a second battery pack, wherein each of the first battery pack and the second battery pack includes a plurality of battery cells for storing an electric charge for powering a traction motor of the electric vehicle; a thermal management system for the first battery pack and the second battery pack, the thermal management system delivering a cooling fluid through the first battery pack and the second battery pack; a plurality of valves that control the flow of the cooling fluid to each of the first battery pack and the second battery pack; a control system operably connected to the valve to control operation of the valve to control flow of the cooling fluid to each of the first and second battery packs; a sensor arrangement that sends signals to the control system, wherein the signals indicate whether any of the plurality of cells in the first battery pack is at risk of thermal runaway and whether any of the plurality of cells in the second battery pack is at risk of thermal runaway; The control system includes a processor and a memory, and the memory contains program code that can be executed by the processor to perform the following operations: a) determining whether the first battery pack is at risk of thermal runaway based on the signal; b) determining whether the second battery pack is at risk of thermal runaway based on the signal; c) based on determining in steps a) and b) that the first battery pack is at risk of thermal runaway and the second battery pack is not at risk of thermal runaway, operating the plurality of valves to increase flow of the cooling fluid to the first battery pack and to decrease flow of the cooling fluid to the second battery pack; and d) based on determining in steps a) and b) that the first battery pack is at risk of thermal runaway and the second battery pack is not at risk of thermal runaway, operating the plurality of valves to increase flow of the cooling fluid to the first battery pack and to decrease flow of the cooling fluid to the second battery pack.

11. The battery system according to claim 10, wherein: The cooling fluid is a coolant, And wherein the thermal management system includes a coolant system, the coolant system includes a radiator, a heater, a cooler, at least one pump, and wherein the coolant system also includes a refrigerant system, the refrigerant system includes a refrigerant, a compressor, a condenser and an expansion valve, wherein the cooler exchanges heat between the coolant and the refrigerant.

12. The battery system according to claim 11, wherein: The memory contains program code executable by the processor during steps c) and d) to perform the following operations: e) operating the refrigerant system to cool the refrigerant, and f) controlling the plurality of valves to direct the coolant through the chiller, thereby cooling the coolant by the refrigerant in the chiller.

13. The battery system according to claim 12, wherein: The thermal management system further comprises a heat storage tank, wherein the heat storage tank contains a secondary cooling medium. The memory contains program code that can be executed by the processor during steps c) and d) to perform the following operations: g) controlling the plurality of valves to direct the coolant through the thermal storage tank, thereby cooling the coolant by the secondary cooling medium.

14. The battery system according to claim 11, wherein: the sensor arrangement comprising a plurality of temperature sensors positioned to send signals indicative of a temperature of the first battery pack and a temperature of the second battery pack to the control system; The memory further includes program code that can be executed by the processor to perform the following operations: h) determining, based on the signal, whether a temperature of at least one of the first battery pack and the second battery pack is less than a first threshold battery pack temperature; and i) based on the determination in step h), controlling the plurality of valves to direct the coolant through the heater to heat the at least one of the first battery pack and the second battery pack so that the temperature of the at least one of the first battery pack and the second battery pack is above the first threshold battery pack temperature and within a selected operating temperature range of the at least one of the first battery pack and the second battery pack.

15. The battery system according to claim 11, wherein: The sensor arrangement comprises an ambient temperature sensor positioned to send a signal indicative of ambient temperature to the control system; The memory further includes program code that can be executed by the processor to perform the following operations: j) determining, based on the signal, whether the ambient temperature is less than a first threshold ambient temperature; k) determining whether a cooling load indication value for at least the first battery pack and the second battery pack is below a selected cooling load indication value; and l) Based on the determinations in steps j) and k), controlling the plurality of valves to direct the coolant through the radiator to maintain at least the first battery pack and the second battery pack below a selected upper threshold battery pack temperature.

16. The battery system according to claim 17, wherein: The memory also includes program code executable by the processor to: m) determining, based on the signal, whether the ambient temperature is above the first threshold ambient temperature and / or whether the cooling load indication value for at least the first battery pack and the second battery pack is above a selected cooling load indication value; as well as n) based on whether step m) produces a determination that the ambient temperature is above the first threshold ambient temperature and / or a determination that the cooling load indication value for at least the first battery pack and the second battery pack is above a selected cooling load indication value, operate the refrigerant system and control the plurality of valves to direct the coolant through the cooler to maintain at least the first battery pack and the second battery pack below a selected upper threshold battery pack temperature.

17. The battery system according to claim 11, wherein: The sensor arrangement comprises a secondary coolant medium temperature sensor positioned to send a signal indicative of a temperature of the secondary coolant medium to the control system, and The memory further includes program code that can be executed by the processor to perform the following operations: m) based on the signal, determining that the temperature of the secondary cooling medium is above a selected threshold temperature for the secondary cooling medium; and n) based on the determination in step m) and based on the determination in steps a) and b) that the first battery pack is not at risk of thermal runaway and the second battery pack is not at risk of thermal runaway, operating the refrigerant system and controlling the plurality of valves to direct the coolant through the cooler and through the secondary cooling tank to maintain at least the first battery pack and the second battery pack below a selected upper threshold battery pack temperature.

18. A bus bar for a battery module including a battery cell having a battery cell terminal, the bus bar comprising: A first contact surface for contacting the cell terminal, wherein the contact surface is textured (e.g., recessed, grooved) to define: a first upper portion; a second upper portion; and a lower portion; wherein the lower portion is horizontally disposed between the upper portions and connected to the upper portions; wherein the upper portion is disposed above the lower portion, and a first vertical distance and a second vertical distance greater than the first vertical distance are between the upper portion and the lower portion; and The upper parts are separated by a first horizontal dimension (w-min: for example, 1.0 mm) and a second horizontal dimension (w-max) larger than the first horizontal dimension.

19. A method of operating a battery pack comprising a module, the module comprising a module housing, the module housing comprising a first module housing member and a second module housing member, and the module including a bus bar in contact with a plurality of battery cells, the method comprising: regulating the temperature of the plurality of battery cells using a cooling liquid flowing through the module housing and in which the plurality of battery cells are immersed; Charging or discharging the battery pack at a rate of at least 2C; removing one or more of the plurality of cells from the battery pack by removing the second module housing member from the first housing member to disengage the bus bar from the plurality of cells, thereby electrically disconnecting the plurality of cells from each other; as well as The removed one or more cells are replaced with one or more replacement cells.

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