WO2019071184A1

WO2019071184A1 - Lithium ion battery

Info

Publication number: WO2019071184A1
Application number: PCT/US2018/054693
Authority: WO
Inventors: Jason D. Fuhr; Richard M. Dekeuster; Jennifer L. CZARNECKI
Original assignee: Johnson Controls Technology Co
Current assignee: Johnson Controls Technology Co
Priority date: 2017-10-06
Filing date: 2018-10-05
Publication date: 2019-04-11
Anticipated expiration: 2020-04-06

Abstract

A lithium-ion (Li-ion) battery (28) includes a plurality of battery cell stacks (50), wherein each battery cell stack (50) of the plurality of battery cell stacks (50) includes a plurality of Li-ion battery cells (54). The Li-ion battery (28) also includes a battery housing (42), the battery housing (42) having a plurality of cell compartments (74) formed by internal dividers (72) integral with the battery housing (42). Each cell compartment (74) of the plurality of cell compartments (74) is sized to receive a corresponding one battery cell stack (50) of the plurality of battery cell stacks (50).

Description

LITHIUM ION BATTERY

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application Serial No. 62/568,957, entitled "BATTERY," filed 6 October 2017, and which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND

[0002] The present disclosure relates generally to the field of batteries and battery modules. More specifically, the present disclosure relates to a battery configured to accommodate one or more lithium-ion battery cells within a packaging normally used to contain lead acid battery cells.

[0003] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0004] A vehicle that uses one or more battery systems for providing all or a portion of the motive power for the vehicle can be referred to as an xEV, where the term "xEV" is defined herein to include all of the following vehicles, or any variations or combinations thereof, that use electric power for all or a portion of their vehicular motive force. For example, xEVs include electric vehicles (EVs) that utilize electric power for all motive force. As will be appreciated by those skilled in the art, hybrid electric vehicles (HEVs), also considered xEVs, combine an internal combustion engine propulsion system and a battery-powered electric propulsion system, such as 48 Volt (V) or 130V systems. The term HEV may include any variation of a hybrid electric vehicle. For example, full hybrid systems (FHEVs) may provide motive and other electrical power to the vehicle using one or more electric motors, using only an internal combustion engine, or using both. In contrast, mild hybrid systems (MHEVs) disable the internal combustion engine when the vehicle is idling and utilize a battery system to continue powering the air conditioning unit, radio, or other electronics, as well as to restart the engine when propulsion is desired. The mild hybrid system may also apply some level of power assist, during acceleration for example, to supplement the internal combustion engine. Mild hybrids are typically 96V to 130V and recover braking energy through a belt or crank integrated starter generator. Further, a micro- hybrid electric vehicle (mHEV) also uses a "Stop-Start" system similar to the mild hybrids, but the micro-hybrid systems of a mHEV may or may not supply power assist to the internal combustion engine and operates at a voltage below 60V. For the purposes of the present discussion, it should be noted that mHEVs typically do not technically use electric power provided directly to the crankshaft or transmission for any portion of the motive force of the vehicle, but an mHEV may still be considered as an xEV since it does use electric power to supplement a vehicle's power needs when the vehicle is idling with internal combustion engine disabled and recovers braking energy through an integrated starter generator. In addition, a plug-in electric vehicle (PEV) is any vehicle that can be charged from an external source of electricity, such as wall sockets, and the energy stored in the rechargeable battery packs drives or contributes to drive the wheels. PEVs are a subcategory of EVs that include all-electric or battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and electric vehicle conversions of hybrid electric vehicles and conventional internal combustion engine vehicles.

[0005] xEVs as described above may provide a number of advantages as compared to more traditional gas-powered vehicles using only internal combustion engines and traditional electrical systems, which are typically 12V systems powered by a lead acid battery. For example, xEVs may produce fewer undesirable emission products and may exhibit greater fuel efficiency as compared to traditional internal combustion vehicles and, in some cases, such xEVs may eliminate the use of gasoline entirely, as is the case of certain types of EVs or PEVs.

[0006] As technology continues to evolve, there is a need to provide improved power sources, particularly battery modules, for such vehicles. For example, lithium ion batteries may have a number of advantages over lead-acid batteries, but there are also technical hurdles to address in replacing lead-acid batteries with lithium ion batteries. For instance, lithium ion batteries and the battery cells they use may have a higher sensitivity to environmental conditions, overcharge and overdischarge, and so forth, relative to their lead-acid counterparts. Further, while a greater state of charge operating range may be available for lithium ion batteries relative to lead-acid batteries, particularly in vehicles, the ability to use this larger range may depend on the ability to maintain the lithium ion battery cells in a stable operating state.

[0007] These are but some of the technical challenges associated with replacing a lead-acid battery with a lithium ion battery. Thus, it is now recognized that there is a need for an improved lithium ion battery construction that addresses these and/or other technical problems associated with the use of lithium ion batteries in place of lead-acid batteries.

SUMMARY

[0008] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

[0009] The present disclosure relates to a lithium-ion (Li-ion) battery including a plurality of battery cell stacks, wherein each battery cell stack of the plurality of battery cell stacks includes a plurality of Li-ion battery cells. The Li-ion battery also includes a battery housing, the battery housing having a plurality of cell compartments formed by internal dividers integral with the battery housing. Each cell compartment of the plurality of cell compartments is sized to receive a corresponding one battery cell stack of the plurality of battery cell stacks.

[0010] The present disclosure also relates to a battery housing having a plurality of cell compartments, each cell compartment of the plurality of cell compartments sized to receive a battery cell stack. The plurality of cell compartments are formed by a plurality of dividers that are integrally formed with the battery housing. At least one housing support structure is integral with the battery housing and coupled to at least one divider of the plurality of dividers and a wall defining an interior of the battery housing.

[0011] The present disclosure further relates to a lithium-ion (Li-ion) battery having a plurality of battery cell stacks. Each battery cell stack of the plurality of battery cell stacks comprises a plurality of Li-ion battery cells, and each battery cell stack includes a first cell frame and a second cell frame at least partially surrounding the plurality of Li-ion battery cells of the battery cell stack. The first cell frame includes an alignment tab positioned within a corresponding alignment recess of the second cell frame. A battery housing of the Li-ion battery includes a plurality of cell compartments, each cell compartment of the plurality of cell compartments holding a corresponding one battery cell stack of the plurality of battery cell stacks.

DRAWINGS

[0012] Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which:

[0013] FIG. 1 is a perspective view of a vehicle having a battery system configured in accordance with present embodiments to provide power for various components of the vehicle, in accordance with an aspect of the present disclosure;

[0014] FIG. 2 is a cutaway schematic view of an embodiment of the vehicle and the battery system of FIG. 1, in accordance with an aspect of the present disclosure;

[0015] FIG. 3 is a top perspective view of an embodiment of a lithium ion (Li-ion) battery module, in accordance with an aspect of the present disclosure;

[0016] FIG. 4 is an exploded view of the Li-ion battery of FIG. 3 showing the internal components of the battery module, in accordance with an aspect of the present disclosure; [0017] FIG. 5 is a top perspective view of a housing of the Li-ion battery of FIG. 3, showing internal battery cell compartments and an integrated heat sink, in accordance with an aspect of the present disclosure;

[0018] FIG. 6 is a perspective view of an embodiment of a battery cell stack used in the Li-ion battery of FIG. 3 and containing three Li-ion battery cells with cell frames between each cell, in accordance with an aspect of the present disclosure;

[0019] FIG. 7 is an exploded view of the battery cell book of FIG. 6 and showing the internal components of the stack, in accordance with an aspect of the present disclosure;

[0020] FIG. 8 is a perspective view of a partially assembled version of the Li-ion battery of FIG. 3 and depicting the manner in which battery cell stacks may be arranged in a housing of the Li-ion battery, in accordance with an aspect of the present disclosure;

[0021] FIG. 9 is a perspective view of a bus bar assembly used in the Li-ion battery of FIG. 3, in accordance with an aspect of the present disclosure;

[0022] FIG. 10 is an exploded view of the bus bar assembly of FIG. 9, in accordance with an aspect of the present disclosure;

[0023] FIG. 11 is a top perspective view of the Li-ion battery with a top of the module removed to depict the manner in which the bus bar assembly of FIG. 9 is situated within the module, in accordance with an aspect of the present disclosure;

[0024] FIG. 12 is a top perspective view of a cover of the Li-ion battery of the present disclosure having an integrated control assembly, in accordance with an aspect of the present disclosure; and

[0025] FIG. 13 is a underside perspective view of the cover of FIG. 12, in accordance with an aspect of the present disclosure. DETAILED DESCRIPTION

[0026] One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business- related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0027] The battery systems described herein may be used to provide power to various types of electric vehicles (xEVs) and other high voltage energy storage/expending applications (e.g., electrical grid power storage systems). Such battery systems may include one or more battery modules, each battery module having a number of battery cells (e.g., lithium-ion (Li-ion) electrochemical cells) arranged and electrically interconnected to provide particular voltages and/or currents useful to power, for example, one or more components of an xEV. As another example, battery modules in accordance with present embodiments may be incorporated with or provide power to stationary power systems (e.g., non-automotive systems).

[0028] xEVs may include a lead acid battery module (e.g., having an open circuit voltage of 12V at 100% state of charge) and a Li-ion battery (e.g., having an open circuit voltage of between 12.5V and 16V at 100% state of charge) coupled to one another in a parallel configuration. In certain instances, the lead acid battery module may be used to start and/or ignite an internal combustion engine of the xEV, whereas the Li-ion battery may be used to capture power from a regenerative braking system and to provide electricity to vehicle components when the internal combustion engine is idle. Additionally or alternatively, the Li-ion battery may be utilized as a starter battery and provide power to start and/or ignite an internal combustion engine of the xEV. Accordingly, Li-ion batteries in 12V vehicle architectures can apply to 12V Dual Energy Storage Systems (DESS) and 12V starter applications. To provide for sufficient storage and discharge capacity, Li-ion batteries include a plurality of individual Li-ion battery cells, and it is presently recognized that such battery cells may be arranged within the battery module in a particular manner to provide for more efficient operation and longer lifetimes. Accordingly, present embodiments include a battery, or an assembly for a battery module that allows for efficient operation and smaller footprint construction relative to certain other Li-ion battery designs.

[0029] To simplify the following discussion, the present techniques will be described in relation to a battery system with a 12 volt Li-ion battery and a 12 volt lead-acid battery. However, one of ordinary skill in art is able to adapt the present techniques to other battery systems, such as a battery system with a 48 volt lithium ion battery and a 12 volt lead-acid battery, systems that utilize high voltage (HV) lithium ion battery systems, stationary energy storage systems, and the like.

[0030] To help illustrate, FIG. 1 is a perspective view of an embodiment of a vehicle 10, which may utilize a regenerative braking system. Although the following discussion is presented in relation to vehicles with regenerative braking systems, the techniques described herein are adaptable to other vehicles that capture/store electrical energy with a battery, which may include electric-powered and gas-powered vehicles.

[0031] As discussed above, it would be desirable for a battery system 12 to be largely compatible with traditional vehicle designs. Accordingly, the battery system 12 may be placed in a location in the vehicle 10 that would have housed a traditional battery system. For example, as illustrated, the vehicle 10 may include the battery system 12 positioned similarly to a lead-acid battery of a typical combustion-engine vehicle (e.g., under the hood of the vehicle 10). Furthermore, as will be described in more detail below, the battery system 12 may be positioned to facilitate managing temperature of the battery system 12. For example, in some embodiments, positioning a battery system 12 under the hood of the vehicle 10 may enable an air duct to channel airflow over the battery system 12 and cool the battery system 12. [0032] A more detailed view of the battery system 12 is described in FIG. 2. As depicted, the battery system 12 includes an energy storage component 14 coupled to an ignition system 16, an alternator 18, a vehicle console 20, and optionally to an electric motor 22. Generally, the energy storage component 14 may capture/store electrical energy generated in the vehicle 10 and output electrical energy to power electrical devices in the vehicle 10.

[0033] In other words, the battery system 12 may supply power to components of the vehicle's electrical system, which may include radiator cooling fans, climate control systems, electric power steering systems, active suspension systems, auto park systems, electric oil pumps, electric super/turbochargers, electric water pumps, heated windscreen/defrosters, window lift motors, vanity lights, tire pressure monitoring systems, sunroof motor controls, power seats, alarm systems, infotainment systems, navigation features, lane departure warning systems, electric parking brakes, external lights, or any combination thereof. Illustratively, in the depicted embodiment, the energy storage component 14 supplies power to the vehicle console 20, a display 21 within the vehicle, and the ignition system 16, which may be used to start (e.g., crank) an internal combustion engine 24.

[0034] Additionally, the energy storage component 14 may capture electrical energy generated by the alternator 18 and/or the electric motor 22. In some embodiments, the alternator 18 may generate electrical energy while the internal combustion engine 24 is running. More specifically, the alternator 18 may convert the mechanical energy produced by the rotation of the internal combustion engine 24 into electrical energy. Additionally or alternatively, when the vehicle 10 includes an electric motor 22, the electric motor 22 may generate electrical energy by converting mechanical energy produced by the movement of the vehicle 10 (e.g., rotation of the wheels) into electrical energy. Thus, in some embodiments, the energy storage component 14 may capture electrical energy generated by the alternator 18 and/or the electric motor 22 during regenerative braking. As such, the alternator 18 and/or the electric motor 22 are generally referred to herein as a regenerative braking system. [0035] To facilitate capturing and supplying electric energy, the energy storage component 14 may be electrically coupled to the vehicle's electric system via a bus 26. For example, the bus 26 may enable the energy storage component 14 to receive electrical energy generated by the alternator 18 and/or the electric motor 22. Additionally, the bus 26 may enable the energy storage component 14 to output electrical energy to the ignition system 16 and/or the vehicle console 20. Accordingly, when a 12 volt battery system 12 is used, the bus 26 may carry electrical power typically between 8-18 volts.

[0036] Additionally, as depicted, the energy storage component 14 may include multiple battery modules. For example, in the depicted embodiment, the energy storage component 14 includes a lead acid (e.g., a first) battery module 28 in accordance with present embodiments, and a lithium ion (e.g., a second) battery module 30, where each battery module 28, 30 includes one or more battery cells. In other embodiments, the energy storage component 14 may include any number of battery modules. Additionally, although the first battery module 28 and the second battery module 30 are depicted adjacent to one another, they may be positioned in different areas around the vehicle. For example, the second battery module 30 may be positioned in or about the interior of the vehicle 10 while the first battery module 28 may be positioned under the hood of the vehicle 10.

[0037] In some embodiments, the energy storage component 14 may include multiple battery modules to utilize multiple different battery chemistries. For example, the first battery module 28 may utilize a lead-acid battery chemistry and the second battery module 30 may utilize a lithium ion battery chemistry. In such an embodiment, the performance of the battery system 12 may be improved since the lithium ion battery chemistry generally has a higher coulombic efficiency and/or a higher power charge acceptance rate (e.g., higher maximum charge current or charge voltage) than the lead-acid battery chemistry. As such, the capture, storage, and/or distribution efficiency of the battery system 12 may be improved.

[0038] To facilitate controlling the capturing and storing of electrical energy, the battery system 12 may additionally include a control module 32. More specifically, the control module 32 may control operations of components in the battery system 12, such as relays (e.g., switches) within energy storage component 14, the alternator 18, and/or the electric motor 22. For example, the control module 32 may regulate amount of electrical energy captured/supplied by each battery module 28 or 30 (e.g., to de-rate and re-rate the battery system 12), perform load balancing between the battery modules 28 and 30, determine a state of charge of each battery module 28 or 30, determine temperature of each battery module 28 or 30, determine a predicted temperature trajectory of either battery module 28 and 30, determine predicted life span of either battery module 28 or 30, determine fuel economy contribution by either battery module 28 or 30, determine an effective resistance of each battery module 28 or 30, control magnitude of voltage or current output by the alternator 18 and/or the electric motor 22, and the like.

[0039] Accordingly, the control module (e.g., unit) 32 may include one or more processors 34 and one or more memories 36. More specifically, the one or more processors 34 may include one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more general purpose processors, or any combination thereof. Generally, the processor 34 may perform computer-readable instructions related to the processes described herein. Additionally, the processor 34 may be a fixed-point processor or a floating-point processor.

[0040] Additionally, the one or more memories 36 may include volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as readonly memory (ROM), optical drives, hard disc drives, or solid-state drives. In some embodiments, the control module 32 may include portions of a vehicle control unit (VCU) and/or a separate battery control module. Additionally, as depicted, the control module 32 may be included separate from the energy storage component 14, such as a standalone module. In other embodiments, the battery management system (BMS) may be included within the energy storage component 14.

[0041] In certain embodiments, the control module 32 or the processor 34 may receive data from various sensors 38 disposed within and/or around the energy storage component 14. The sensors 38 may include a variety of sensors for measuring current, voltage, temperature, and the like regarding the battery module 28 or 30. After receiving data from the sensors 38, the processor 34 may convert raw data into estimations of parameters of the battery modules 28 and 30. As such, the processor 34 may render the raw data into data that may provide an operator of the vehicle 10 with valuable information pertaining to operations of the battery system 12, and the information pertaining to the operations of the battery system 12 may be displayed on the display 21. The display 21 may display various images generated by device 10, such as a GUI for an operating system or image data (including still images and video data). The display 21 may be any suitable type of display, such as a liquid crystal display (LCD), plasma display, or an organic light emitting diode (OLED) display, for example. Additionally, the display 21 may include a touch-sensitive element that may provide inputs to the adjust parameters of the control module 32 or data processed by the processor 34.

[0042] As set forth above, the present disclosure relates to the design and assembly of a Li-ion battery for use in xEVs, for instance to replace or supplement the presence of a lead-acid battery. In this respect, FIG. 3 is an overhead perspective view of an embodiment of the Li-ion battery module 28, which may also be referred to herein as a Li-ion battery. The illustrated embodiment of the Li-ion battery module 28 includes an enclosure 40 formed by a battery housing 42, a cover 44, and cover plates 46.

[0043] As described in further detail with respect to later figures, the cover 44 includes integrated battery terminals 48a and 48b for interconnection to the device to be powered, e.g., xEV 10. In certain embodiments, the battery housing 42 is of a standard lead-acid form factor, i.e., a form factor for a lead-acid battery that corresponds to a standard established by way of a number that may correspond to any one of the many group representations (e.g., Battery Council International (BCI) group numbers, Deutsche Industrie Normen (DIN codes), European Norm (EN) codes) established for traditional lead acid batteries (e.g., lead acid battery module 30). Each group (e.g., group number) from these established set of standards has a standard length and width for the base of the particular battery corresponding to the particular group designation. However, the present disclosure is not limited to such embodiments, and the battery housing 42 can be of any shape, including regular or irregular shapes, (e.g., generally rectangular or square), and is sized to house the internal components of the Li-ion battery 28.

[0044] As also shown, the cover 44 has a vent port 50 to allow for venting of battery cell effluent to an external environment, for example via a hose connection. The vent port 50 may be integrally formed (e.g., molded into) the cover 44. The cover 44 also includes a signal connector 52 to allow for a secure connection between the battery module 32, which is located within the enclosure 40, and an external device, such as a vehicle control module of the xEV 10.

[0045] FIG. 4 is an exploded view of the Li-ion battery module 28, illustrating certain internal components contained within the enclosure 40. Specifically, the Li-ion battery module 28 includes a plurality of battery cell stacks 50 positioned within a cell region 52 of the battery housing 42. As described in further detail below, each battery cell stack 50 may be independently secured within the battery housing 42 by internal partitions integrally formed within the housing 42.

[0046] Each battery cell stack 50 of the plurality of battery cell stacks 50 includes at least one battery cell 54, such as two or more battery cells 54. Further, the battery cell stacks 50 each include at least one cell frame 56, which may function as a rigid support member for each battery cell stack 50. As illustrated in FIG. 4, respective terminals 58a and 58b of each battery cell 54 are oriented away from a base 60 of the battery housing 42 to allow for ready connection with other features of the Li-ion battery module 28. Further details relating to the battery cell stacks 50 are set forth below with respect to FIG. 6.

[0047] The illustrated Li-ion battery module 28 of FIG. 4 also includes a bus bar assembly 62 configured to interface with and electrically interconnect the battery cells 54, the components of which are described in further detail below with respect to FIGS. 9 and 10. As depicted, the bus bar assembly 62 is situated between the plurality of battery cells 54 and electronics 64 contained within and/or integrated with the lid 44. In accordance with certain embodiments, the bus bar assembly 62 allows the transmission of low voltage signals (e.g., sensor signals) as well as higher voltage power flow to certain of the electronics 64 from the plurality of battery cells 54.

[0048] The Li-ion battery also includes a heat sink 66 configured to allow cooling of the battery cells 54. In one embodiment, the heat sink 66 is an integrated heat sink molded onto or into the battery housing 42. The heat sink 66 may be integrated at the base 60 of the battery housing 42.

[0049] Because of the structure of the Li-ion battery module 28 and its integrated components, the plurality of battery cells 54 can be housed within dimensions typically reserved for a lead-acid battery housing, such as an LN2 housing. Thus, the present disclosure advantageously allows for Li-ion batteries and their internal connections to be fully contained in the battery housing 42 that has, in certain embodiments, the same size used for a lead-acid battery housing. This also allows for ready replacement of standard-sized lead-acid motor vehicle car batteries with Li-ion based assemblies.

[0050] FIG. 5 is an illustration of the battery housing 42 of the Li-ion battery module 28 in an open configuration, i.e., without cover 44 and without any internal elements such as the plurality of battery cell stacks 50. The heat sink 64 is provided along a bottom surface 70 of battery housing 42. In the embodiment shown in FIG. 5, battery housing 42 includes a plurality of dividers 72, such that a plurality of cell compartments 74 are formed within battery housing 42. Each cell compartment 74 may be isolated from every other cell compartment 74 within the battery housing 42, meaning that the battery cell stack 50 present within a particular one of the cell compartments 74 is unable to physically contact the battery cell stack 50 positioned within an adjacent one of the cell compartments 74.

[0051] In certain embodiments, the dividers 72 are integrally formed within the battery housing 42 and extend along an entire width of the cell region 52, and/or an entire height of the cell region 52. In other words, the dividers 72 may be internal walls dividing the cell region 52 into the cell compartments 74. [0052] The dividers 72 may also, as illustrated, include ribs 76 positioned to match an approximate width of each of the battery cell stacks 50. In certain embodiments, the ribs 76 may maintain the position of the battery cell stacks 50 within the cell compartments 74 to allow an available space 78 to remain between the battery cell stacks 50 and outer walls 80 of the battery housing 42. The available space 78 may allow for some degree of expansion of the battery cell stacks 50, and also provide additional space to receive cell effluent in the event that one or more of the battery cells 54 vents cell effluent. This may alleviate the effects of rapid pressure increases on the Li-ion battery module 28 and its components.

[0053] The illustrated battery housing 42 also includes a plurality of reinforcing ribs 82 (e.g., housing support structures) positioned between the two outermost cell compartments 74a and 74b. The plurality of reinforcing ribs 82 may be oriented crosswise (e.g., orthogonally) relative to the dividers 72 to allow for structural reinforcement. For instance, the dividers 72 may have some degree of flexibility due to the polymeric nature of the battery housing 42. Because the battery cells 54 and, accordingly, the battery cell stacks 50 may swell during operation, a normal force may be applied to the dividers 72 during operation. Thus, the reinforcing ribs 82 oppose the normal force applied by cell swelling, which may otherwise deform the dividers 72 and/or other parts of the battery housing 42. Further, additional spaces 84 present between the reinforcing ribs 82 may serve as additional pressure relief features in the event that one or more of the battery cells 54 vents cell effluent. Although FIG. 5 shows parallel reinforcing ribs 82, it is understood that other patterns may be used. In some embodiments, the reinforcing ribs 82 are manufactured, e.g., molded, as part of the battery housing 42 so that the reinforcing ribs 82 form a unitary element with the overall shell of the battery housing 42 and the cell compartments 74.

[0054] The embodiment shown in FIG. 5 includes four cell compartments 74. Each cell compartment 74 is sized to fit a corresponding one of the battery cell stacks 50. In the configuration shown in FIG. 5, there are six total compartments, as lead-acid battery housings, such as LN2 housings, house six lead-acid battery cells, with the size of each battery cell stack 50 approximating the size of one of the lead-acid battery cells. In the configuration shown in FIG. 5, because only four H4-sized Li-ion battery cell stacks 50 are needed instead of six H6-sized lead-acid battery cells to produce a 12V battery, four of the six compartments are cell compartments 74 sized to receive a battery cell stack 50, while the two outer compartments are used to provide the reinforcing ribs 82, which provide reinforcement for expansion pressure from the lithium-ion battery cells 54 and overall structural support of the Li-ion battery module 28. Thus, the battery housing 42 can be an LN2-sized housing used to house four Li-ion battery stacks 50, the two outer compartments being used as reinforcing ribs 82, without the need to provide a new housing assembly, or an adapter to accommodate what would be a four-cell LN1 Li-ion battery.

[0055] As shown in FIG. 5, each of the cell compartments 74 in the battery housing 42 is sized to fit a corresponding one of the battery cell stacks 50. The battery cell stacks 50 may be further appreciated with reference to FIGS. 6 and 7, where FIG. 6 is a side perspective view of the battery cell stack 50 and FIG. 7 is an exploded view of the battery cell stack 50.

[0056] As shown in FIG. 6, the battery cell stack 50 includes at least two battery cells 54 supported by cell frames 56. The cell frames 56 each include alignment features - specifically, an alignment tab 90 positioned at a side 92 of the frame 56 oriented orthogonal to terminal ends 94 (where the terminals 58a and 58b are located) of the battery cells 54. The alignment tab 90 aligns and forms a nested arrangement with a corresponding recess 96 of an adjacent cell frame 56. This nested arrangement may be desirable to facilitate proper orientation of the battery cells 54 within the battery cell stacks and also within the Li-ion battery module 28.

[0057] The battery cell stack 50 is arranged as a stack of various features shown in FIG. 7. In the illustrated embodiment of FIG. 7, the battery cell stack 50 contains three lithium-ion battery cells 54a, 54b, 54c, and two cell frames 56a, 56b disposed therebetween. As shown, the battery cell stack 50 is a "book" of components and includes battery cells 54a, 54c disposed at each end of battery cell stack 50 and another of the battery cells 54b disposed between two cell frames 56. A cell cold plate 98 is also provided as part of the battery cell stack 50. In one embodiment, the cell cold plate 98 is an aluminum sheet that extends down to provide a thermally conductive path to the heat sink 64 (of FIGS. 3 and 4). The cell cold plate 98 may include a lower portion 100 positioned on an opposite end relative to the terminal ends 94, and which extends crosswise relative to a main portion 102 of the cell cold plate 98 (and substantially parallel to the heat sink 64) to enhance surface area contact with the heat sink 64.

[0058] In some embodiments, a separator 104 is provided between the lithium-ion battery cells 54. In some embodiments, the separator 104 is a film with pressure sensitive adhesive (PSA). The separator 104 may be electrically insulative but thermally conductive to allow heat transfer between the cells 54 and to the cell cold plate 98. Indeed, because the cell frames 56 have an opening 106 corresponding to active regions 108 of the battery cells 54 (where a majority of heat is generated by the cells 54), the separators 104 may be configured to transfer a majority of the heat away from the cells 54. In other embodiments, the separator 104 may have a relatively low thermal conductivity compared to the cell frame 56, and a majority of the heat transfer from the cells 54 may be by way of the frame 56. A thermal pad or epoxy 110 may be positioned between the battery cell stack 50 and the heat sink 64 to encourage maximum heat transfer to away from the stack 50.

[0059] It should be noted that present embodiments are not limited to cell stacks 50 having three Li-ion battery cells 54. In some embodiments, the cell stacks 50 can have a single Li-ion battery cell 54 or a plurality of Li-ion battery cells 54. In some embodiments the Li-ion battery cells 54 of each cell stack 50 may be electrically connected in parallel, series, or a series - parallel connection as described below. In the illustrated embodiment, the battery cells 54 of each battery cell stack 50 are electrically connected in parallel, for example to increase capacity of each battery cell stack 50. Adjacent battery cell stacks 50 may be coupled in series, for example to increase the overall voltage of the battery module 28, or in parallel, for example to increase capacity. In the illustrated embodiment of FIG. 8, for instance, adj acent battery cell stacks 50 are electrically coupled in series.

[0060] In FIG. 8, each of four cell stacks 50a, 50b, 50c, 50d are shown as inserted within its own cell compartment 74 in the battery housing 42. Each battery cell stack 50 includes three battery cells 54 as shown in FIG. 7. It should be noted that although the figures show a battery housing 42 having four cell compartments 74 each sized to receive one battery cell stack 50, it is within the scope of the present disclosure to provide an embodiment of the battery housing 42 that can include any number of cell compartments 74 (e.g., more or less than four) and thus can house any number of cell stacks 50, and therefore any number of battery cells 54. Additional (or fewer) dividers 72 can be used to create a different number of cell compartments 74 to accommodate the number of cell stacks 50 needed to be housed in housing 42. Further, each battery cell stack 50 does not need to include only three battery cells 54. In other words, each battery cell stack 50 may be designed to include more or fewer battery cells 54 than the three battery cells 54. It is also noted that should the number of battery cells 54 per battery cell stack 50 be altered, the number of cell frames 56 and separators 104 may also need to be altered to account for the different number of battery cells 54 in battery cell stack 50.

[0061] FIGS. 9 and 10 depict an embodiment of the bus bar assembly 62, which is positioned between the cover 44 and the cell stacks 50 of Li-ion battery module 28 (as shown, for example, in FIG. 3). In the illustrated embodiment, the bus bar assembly 62 includes a flex circuit 120, bus bars 121 configured to electrically and physically couple to the terminals 58a, 58b of the battery cells 54, and bi-metal bridges 122 coupling certain of the bus bars 121 together. In one embodiment, the bi-metal bridges 122 are formed of copper and aluminum.

[0062] In the illustrated embodiment, the bus bars 121 include first bus bars 121 a and second bus bars 121b, which may correspond to the different metals of the bi-metal bridges 122. More specifically, the first bus bars 121 a may be the same metal as the metal used to construct the first terminal 58a of the battery cells 54, and the second bus bars 121b may be the same metal as the metal used to construct the second terminal 58b of the battery cells 54. In one embodiment, the first bus bars 121 a are aluminum for interconnection to aluminum terminals of the battery cells 54, and the second bus bars 121b are copper for interconnection to copper terminals of the battery cells 54. The bi-metal bridges 122 allow for electrical interconnection between the first bus bars 121 a and the second bus bars 121b. [0063] As also illustrated, the bus bars 121 each have a comb structure. In particular, the bus bars 121 include a main portion 124 and a plurality of fingers 126 protruding from the main portion 124. The number of fingers 126 protruding from the main portion 124 generally corresponds to the number of battery cells 54 to which the bus bar 121 is intended to connect, although certain of the bus bars 121 may be used to connect to main bus bars of the Li-ion battery module 28, as described in further detail below with respect to FIGS. 12 and 13. The fingers 126 are illustrated as having an L-shape, with a first portion 128 of the fingers 126 being oriented parallel to the main portion 124, crosswise relative to the battery cells 54, and parallel to the base 60 of the battery housing 54, and a second portion 130 oriented crosswise (orthogonal) relative to the first portion 128. The first portion 128 of the fingers 126 may be useful for connection to various sensing features, for example via interconnection by way of flex circuit fingers 132. The second portion 130 of the fingers 126 may be oriented to be parallel with the terminals 58 of the battery cells 54, which facilitates connection in embodiments where the terminals 58 are tabs (e.g., as in certain pouch battery cell configurations).

[0064] In one embodiment, the flex circuit 120 is a polymer film with flexible traces therein which are connected to the bus bars 121 and, in conjunction with an integrated circuit (IC) chip 134, (discussed below) senses and monitors the voltage of each battery cell stack 50. Additionally or alternatively, the IC chip 134 may monitor the voltage of each battery cell 54. In one embodiment, each bus bar 121 is connected to a terminal of an individual battery cell 54, and the flex circuit 120 may be electrically connected to any one or a combination of the battery cell terminals 58 in the battery cell stack 50. Thus, the voltage of the battery cells 54 in each battery cell stack 50 can be detected by a voltage sensor in flex circuit 120 via the electrical connection between the bus bar 121 in electrical communication with a corresponding battery cell stack 50 terminal and the circuitry within flex circuit 120.

[0065] The flex circuit 120, IC chip 134, bus bars 121 , and bi-metallic bridges 122 are all held together on a carrier 136. The carrier 136 is generally of insulative, polymeric construction and may take a number of forms. However, as illustrated, the carrier 136 is a tray structure formed by a lip 138 on each side of the carrier 136, the sides having the lips 138 extending along a longitudinal axis 140 of the flex circuit 120. In certain embodiments, the lip 138 may have a depth that corresponds to the thickness of the bus bars 121. In this way, the entire assembled bus bar assembly 62 may be handled without creating an inadvertent electrical pathway. That is, the bus bars 121 may not be exposed from the side.

[0066] As noted above, the IC chip 134 is mounted to the flex circuit 120. In accordance with certain embodiments, the IC chip 134 may correspond to at least a portion of the control module 32 of FIG. 2. For instance, the IC chip 134 includes processing circuitry, which may include memory in communication with a processor such as, for example, a central processing unit (CPU), where the memory has instructions that, when executed by the processor, configure the processor to perform a variety of functions including voltage sensing and monitoring of battery stacks 50. The processing circuitry may include and/or be connected to and/or be configured for accessing (e.g., writing to and/or reading from) the memory, which may include any kind of volatile and/or non-volatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory). Such memory may be configured to store code executable by control circuitry and/or other data, e.g., data pertaining to communication, e.g., configuration and/or address data of nodes, etc. The processing circuitry may be configured to control any of the methods described herein and/or to cause such methods to be performed by the processor. Corresponding instructions may be stored in the memory, which may be readable and/or readably connected to the processing circuitry. In other words, the processing circuitry may include a controller, which may comprise a microprocessor and/or microcontroller and/or FPGA (Field-Programmable Gate Array) device and/or ASIC (Application Specific Integrated Circuit) device. It may be considered that the processing circuitry includes or may be connected or connectable to memory, which may be configured to be accessible for reading and/or writing by the controller and/or the processing circuitry.

[0067] FIG. 11 depicts the Li-ion battery module 28 of FIGS. 3 and 4 with the cover 44 removed. As illustrated, the bus bar assembly 62 is disposed above the cell stacks 50 and, as described above, each bus bar 121 is connected to a corresponding battery cell stack 50 and thus the voltage of the battery cells 54 contained in each battery cell stack 50 can be monitored by a voltage sensor within the flex circuit 120. In one embodiment, laser welding is performed to form electrical interconnections the cell stacks 50 and the bus bar assembly 62. That is, the cell stacks 50 and the bus bar assembly 62 may be coupled by way of a series of laser welds.

[0068] As also shown in FIG. 11, the lip 138 of the carrier 136 is either in line with, or does not protrude beyond, an edge 150 of the battery housing 42 positioned opposite the base 60. Accordingly, the carrier 136 may not necessarily contact features of the cover 44.

[0069] FIG. 12 is a top perspective view and FIG. 13 is an underside perspective view of the cover 44 of the Li-ion battery module 28 of FIGS. 3 and 4. In the illustrated embodiment of FIGS. 12 and 13, handles 160 are attached to cover 44 to allow for transportation of Li-ion battery module 28. However, the handles 160 may not necessarily be present in other embodiments. The connector barrel 52, as set forth above, provides a monitoring interface to allow Li-ion battery module 28 to be in data communication with other components of the powered device, i.e., the xEV 10. As shown in FIG. 4, the cover 44 is placed over the bus bar assembly 62, and includes various electronics. More specifically, the cover 44 is part of an integrated cover and electronics assembly 162, where various electrical and electronic features are integrated into the cover 44.

[0070] In the illustrated embodiment, the features integrated into the cover 44 include the terminals 48a and 48b, as well as module bus bars 164, which are electrically coupled to the terminals 48a and 48b. A control board 166 is electrically and physically connected to first and second module bus bars 164a and 164b, and is physically secured to the cover 44. For example, the control board 166 may be heat staked to the cover 44, or secured by way of a snap fit or other interference connection where protrusions 168 of the cover 44 extend through certain connection holes 170 of the control board 166. [0071] A relay 172 is electrically and physically connected to third and fourth module bus bars 164c and 164d, and may not necessarily be secured directly to the cover 44. For example, the relay 172 may be secured to the cover 44 via the bus bars 164c, 164d, as shown in FIG. 13.

[0072] The first module bus bar 164a, as shown, electrically connects the control board 166 to the first module terminal 48a, and the second module bus bar 164b, as shown, is configured to electrically connect with the bus bar assembly 62, for example to one of the bus bars 161 having a polarity that matches the indicated polarity of the first module terminal 48a. The illustrated control board 166 also includes a circuit 174, such as another integrated circuit similar to IC chip 134. In this regard, the circuit 174 may also form all or a part of the control module 32. Indeed, in one embodiment, the circuit 174 and IC chip 134 couple to one another to produce the control module 32.

[0073] As noted, the control module 32 may be configured to monitor operation of the Li-ion battery module 28, and to control various aspects of the manner in which the Li-ion battery module 28 is charged and discharged. In this regard, the control module 32 may be communicatively coupled to the relay 172 by way of control and sense lines 174. The control module 32 may control the timing of the various on/off states of the relay 172, for example to control the manner in which energy is charged or discharged.

[0074] For example, the third module bus bar 164c, as shown, electrically connects the relay 172 to the second module terminal 48b, and the fourth module bus bar 164d, as shown, is configured to electrically connect with the bus bar assembly 62, for example to one of the bus bars 161 having a polarity that matches the indicated polarity of the second module terminal 48b. The relay 172 may therefore be controlled by the control module 32 to change the relay 172 between an on and an off state, in which case the relay 172 connects and disconnects, respectively, the battery cells 54 from the second module terminal 48b. This has the effect of disconnecting the Li-ion battery module 28 from the powered device (e.g., a vehicle bus). [0075] One or more of the disclosed embodiments, alone or on combination, may provide one or more technical effects including the manufacture of battery modules in a manner that allows Li-ion batteries to replace or supplement lead-acid batteries. The technical effects and technical problems in the specification are exemplary and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

[0076] The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and altematives falling within the spirit and scope of this disclosure.

Claims

CLAIMS: What is claimed is:

1. A lithium-ion (Li-ion) battery comprising:

a plurality of battery cell stacks, wherein each battery cell stack of the plurality of battery cell stacks comprises a plurality of Li-ion battery cells; and

a battery housing, the battery housing comprising a plurality of cell compartments formed by internal dividers integral with the battery housing, wherein each cell compartment of the plurality of cell compartments is sized to receive a corresponding one battery cell stack of the plurality of battery cell stacks.

2. The Li-ion battery of claim 1 , wherein each battery cell stack comprises a cell frame at least partially surrounding a Li-ion battery cell of the plurality of Li-ion battery cells, wherein each cell frame comprises an alignment tab positioned at a side of the cell frame, the side of the cell frame being oriented crosswise with respect to a terminal end of the Li-ion battery cell, and wherein the alignment tab is configured to facilitate proper orientation of the cell stack within a corresponding cell compartment.

3. The Li-ion battery of claim 1, wherein each battery cell stack comprises a first cell frame and a second cell frame at least partially surrounding the plurality of Li-ion battery cells of the battery cell stack, wherein the first cell frame comprises an alignment tab positioned within a corresponding alignment recess of the second cell frame.

4. The Li-ion battery of claim 3, wherein the first cell frame comprises a bend defining the alignment tab and defining another alignment recess configured to receive another alignment tab of an adjacent cell frame.

5. The Li-ion battery of claim 1 , wherein each battery cell stack of the plurality of battery cell stacks comprises a separator positioned between adjacent Li-ion battery cells of the plurality of Li-ion battery cells.

6. The Li-ion battery of claim 5, wherein the each battery cell stack of the plurality of battery cell stacks comprises a cold plate configured to facilitate thermal energy transfer from the cells to a heat sink of the Li-ion battery.

7. The Li-ion battery of claim 6, comprising a thermal transfer pad or epoxy configured to facilitate thermal interface between the cold plate and the heat sink.

8. The Li-ion battery of claim 1 , wherein the plurality Li-ion battery cells comprise a plurality of individually packaged battery cells.

9. The Li-ion battery of claim 1 , wherein the battery housing comprises support ribs extending between and integral with at least one of the dividers and a wall defining an interior of the battery housing.

10. The Li-ion battery of claim 1 , wherein the battery housing is coupled to a cover, wherein the cover comprises:

a first terminal integrated into the cover; and

a first bus bar integrated into the cover, wherein the first bus bar is physically and electrically connected to the first terminal and to a control board, wherein the control board is physically mounted to an interior surface of the cover; and

wherein the control board is physically and electrically connected to a second bus bar extending toward the plurality of battery cell stacks positioned in the battery housing.

11. The Li-ion battery of claim 10, wherein the cover comprises:

a second terminal integrated into the cover; and

a third bus bar integrated into the cover, wherein the second bus bar is physically and electrically connected to the second terminal and to a relay, wherein the relay is physically and electrically connected to a fourth bus bar extending toward the plurality of battery cell stacks positioned in the battery housing.

12. The Li-ion battery of claim 1 , comprising a bus bar assembly positioned between the plurality of battery cell stacks and a cover of the Li-ion battery, wherein the bus bar assembly comprises an electrically insulative carrier and a plurality of bus bars, wherein the plurality of bus bars is physically and electrically coupled to the plurality of battery cell stacks positioned on the insulative carrier, wherein each bus bar of the plurality of bus bars comprises a comb structure.

13. The Li-ion battery of claim 12, wherein the comb structure comprises a main portion and fingers extending from the main portion, wherein the fingers are physically and electrically connected to one terminal of a Li-ion battery cell of a battery cell stack of the plurality of battery cell stacks.

14. The Li-ion battery of claim 13, wherein the bus bar assembly comprises a flex circuit having traces electrically connected to one or more battery cell stacks of the plurality of battery cell stacks by way of corresponding flex circuit fingers overlapping with one or more fingers of the plurality of bus bars.

15. The Li-ion battery of claim 12, wherein the electrically insulative carrier comprises a tray structure configured to receive the plurality of bus bars.

16. A battery housing comprising:

a plurality of cell compartments, each cell compartment of the plurality of cell compartments sized to receive a battery cell stack, wherein the plurality of cell compartments are formed by a plurality of dividers that are integrally formed with the battery housing; and

at least one housing support structure integral with the battery housing and coupled to at least one divider of the plurality of dividers and a wall defining an interior of the battery housing.

17. The battery housing of claim 16, wherein the at least one housing support structure comprises a supporting rib extending from at least one divider of the plurality of dividers and to the wall, wherein the supporting rib is oriented crosswise relative to the at least one divider.

18. The battery housing of claim 16, wherein the battery housing is an LN2 housing.

19. A lithium-ion (Li-ion) battery comprising:

a plurality of battery cell stacks, wherein each battery cell stack of the plurality of battery cell stacks comprises a plurality of Li-ion battery cells, wherein each battery cell stack comprises a first cell frame and a second cell frame at least partially surrounding the plurality of Li-ion battery cells of the battery cell stack, wherein the first cell frame comprises an alignment tab positioned within a corresponding alignment recess of the second cell frame; and

a battery housing, the battery housing comprising a plurality of cell compartments, each cell compartment of the plurality of cell compartments holding a corresponding one battery cell stack of the plurality of battery cell stacks.

20. The Li-ion battery of claim 19, wherein the first cell frame comprises a bend defining the alignment tab and defining another alignment recess configured to receive another alignment tab of an adjacent cell frame.