Patent Publication Number: US-2023142289-A1

Title: In-situ gas detection and monitoring of battery cells during formation and intended use

Description:
INTRODUCTION 
     The information provided in this section is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. 
     The present disclosure relates to battery cell monitoring and/or management systems for battery cells used in vehicles. 
     Advanced energy storage devices and systems are in demand to satisfy energy and/or power requirements for a variety of products, including automotive and non-automotive products such as start-stop systems (e.g., 12V start-stop systems), battery-assisted systems, hybrid electric vehicles (“HEVs”), electric vehicles (“EVs”), network devices, portable electronic devices, electric bikes, power storage devices, etc. These products include batteries, such as lithium-ion batteries and/or other batteries. 
     SUMMARY 
     A battery cell monitoring system is provided and includes: a battery cell including an electrode stack disposed within a case; one or more gas sensors disposed within, attached to or connected to the case and configured to detect levels of one or more gases within the case; and a gas monitoring circuit connected to the one or more gas sensors. The gas monitoring circuit includes: a memory configured to store data collected from the one or more gas sensors; a transceiver configured to transfer the data to a network device separate from the battery cell; and a control module configured to monitor the levels of one or more gases and based on the levels of the one or more gases detect (i) an issue with the battery cell during operative use of the battery cell, (ii) an issue with the battery cell during formation of the battery cell, or (iii) completion of a formation operation of the battery cell. 
     In other features, the gas monitoring circuit is implemented within the case of the battery cell. 
     In other features, the transceiver is configured to wirelessly communicate with the network device. 
     In other features, the transceiver is configured to communicate with the network device via a wired connection. 
     In other features, the gas monitoring circuit is connected to the case via a capillary. 
     In other features, the gas monitoring circuit receives power via a connector and cable and not from the electrode stack. 
     In other features, the control module is configured to detect an issue with the battery cell based on the levels of one or more gases and isolate the battery cell from other battery cells within a battery pack. 
     In other features, the one or more gas sensors are attached to the case of the battery cell. 
     In other features, the one or more gas sensors includes gas sensors serially connected. 
     In other features, the one or more gas sensors include parallel connected gas sensors. 
     In other features, the one or more gas sensors include serially and parallel connected gas sensors. 
     In other features, the battery cell monitoring system further includes switches connected to the one or more gas sensors. The one or more gas sensors includes gas sensors. The control module is configured to control operation of the switches to activate selected ones of the gas sensors. 
     In other features, the control module is configured to: monitor a voltage of the battery cell; ion current levels of gases in the case of the battery cell, where the gases includes the one or more gases; and detect whether the battery cell is fully charged or has an issue based on the voltage and the ion current levels of the gases. 
     In other features, an active safety management system is provided and includes: the battery cell monitoring system of claim  1 ; and gas monitoring circuits connected respectively to cells including the battery cell. The control module is configured to monitor the gas monitoring circuits and detect an outlier cell of the cells and isolate the outlier cell. 
     In other features, a formation system is provided and includes: the battery cell monitoring system; a cycler configured to charge and discharge the battery cell; and a formation monitor configured to control the cycler during formation of the battery cell, communicate with the gas monitoring circuit, and based on the levels of one or more gases, detect an issue with the battery cell or completion of the formation operation of the battery cell. 
     In other features, a battery cell formation method is provided and includes: assembling a battery cell; charging the battery cell to a first predetermined voltage at a first current level; maintaining first predetermined voltage for a first predetermined period of time while allowing a current level of the battery cell to decay from the first current level to a second current level; performing a degassing operation while monitoring levels of one or more gases within the battery cell; and discarding the battery cell based on the levels of the one or more gases. 
     In other features, the battery cell formation method further includes: placing the battery cell in a fixture subsequent to assembling the battery cell; and applying pressure on the battery cell. 
     In other features, the battery cell formation method further includes performing a life capacity check including: charging battery cell to second predetermined voltage at the first current level; maintaining the second predetermined voltage until the current level of the battery cell decays to the second current level; permitting a voltage of the battery cell to drop from the second predetermined voltage to a third predetermined voltage; monitoring the levels of the one or more gases while performing the life capacity check; and discarding the battery cell based on the levels of the one or more gases detected during the life capacity check. 
     In other features, the battery cell formation method further includes performing a resistance check including: charging and discharging the battery cell for a predetermined number of cycles; during a last discharging of the battery cell and when a state-of-charge of the battery cell is at a predetermined level, applying a pulse to the battery cell and measure a direct current resistance of the battery cell; following the last discharging of the battery cell, charging the battery cell to the predetermined level; monitoring the levels of the one or more gases while performing the resistance check; and discarding the battery cell based on the levels of the one or more gases detected during the resistance check. 
     In other features, the battery cell formation method further includes performing an aging process including: heating the battery cell to a predetermined temperature; maintaining the battery cell at the predetermined temperature for a predetermined period; monitoring the levels of the one or more gases while the battery cell is at the predetermined temperature; measuring resistance and voltage of the battery cell at completion of the predetermined period; and based on the levels of the one or more gases, the resistance of the battery cell, and the voltage of the battery cell, discarding the battery cell. 
     Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG.  1    is a functional block diagram of an example apparatus including power source gas monitoring circuits in accordance with the present disclosure; 
         FIG.  2    is a is a functional block diagram of an example vehicle control system including a multiple output dynamic adjustable capacity battery system (MODACS) including an active safety management system (ASMS) and gas monitoring circuits in accordance with the present disclosure; 
         FIG.  3    is a functional block diagram of an example MODACS in accordance with the present disclosure; 
         FIGS.  4 A- 4 B  are a schematic including an example implementation of a MODACS in accordance with the present disclosure; 
         FIG.  5    is a functional block diagram of another example of a vehicle control system including a vehicle control module with an active safety management (ASM) module in accordance with the present disclosure; 
         FIG.  6    is a functional block diagram of an example vehicle including MODACS gas monitoring circuits in accordance with the present disclosure; 
         FIG.  7    is a perspective view of an example electrode stack and tabs of a battery cell; 
         FIG.  8    is a perspective view of an example sealed battery case for the electrode stack of  FIG.  7   ; 
         FIG.  9    is a perspective view of serially connected battery cells and corresponding modules (or blocks) of battery cells; 
         FIG.  10    is a perspective view of a battery pack including modules (or blocks) of battery cells; 
         FIG.  11    is a front view of an example battery cell including wireless gas monitoring circuit in accordance with the present disclosure; 
         FIG.  12    is a front view of an example battery cell including a wired gas monitoring circuit in accordance with the present disclosure; 
         FIG.  13    is functional block diagram of a battery cell monitoring system including a formation monitor in accordance with the present disclosure; 
         FIG.  14    is an example electrode stack in accordance with the present disclosure; 
         FIG.  15    is a functional block diagram of an example gas monitoring circuit in accordance with the present disclosure; 
         FIG.  16    is a functional block diagram of serially connected gas sensors of a battery cell in accordance with the present disclosure; 
         FIG.  17    is an example of parallel and serially connected gas sensors of a battery cell including tuning switches in accordance with the present disclosure; 
         FIG.  18    is a side view of a battery cell including an adhered gas sensor in accordance with the present disclosure; 
         FIG.  19    is a functional block diagram of battery cells connected to communication and power bus bars in accordance with the present disclosure; 
         FIG.  20    is an example gas level versus time plot during battery cell formation and in accordance with the present disclosure; 
         FIG.  21    is an example sensor voltage versus time plot for two different gases in accordance with the present disclosure; 
         FIG.  22    includes an example plot of battery cell voltage versus time and an example plot of ion current versus time during battery cell formation and in accordance with the present disclosure; 
         FIG.  23    is a functional block diagram of an example battery monitoring (or management) system (BMS) module for a battery pack in accordance with the present disclosure; 
         FIG.  24    is a schematic of an example portion of a MODACS circuit in accordance with the present disclosure; and 
         FIGS.  25 A-C  illustrates a battery cell formation method in accordance with the present disclosure. 
     
    
    
     In the drawings, reference numbers may be reused to identify similar and/or identical elements. 
     DETAILED DESCRIPTION 
     All electric and hybrid vehicles can include large battery packs, which include hundreds to thousands of battery cells. As an example, a vehicle may include a MODACS that includes blocks (or strings of cells). A MODACS includes blocks (or strings) of cells. The cells may be connected in series or in parallel. The blocks of cells may also be connected in series or in parallel to provide various output voltages, such as 12V and 48V to power 12V loads and 48V loads. The blocks of cells may be grouped. Each group of blocks of cells may be referred to as a module (or battery module). A MODACS may have multiple battery modules. A MODACS may be implemented as a single battery having a corresponding housing with a negative (or ground reference) terminal and multiple source terminals. Each of the source terminals of a MODACS may have a preset direct current (DC) voltage (e.g., 12 volts (V), 24V, 36V, 48V, etc.) and may supply (or discharge) current or receive current during charging. As an example, the MODACS may include a single 48V source terminal, a first 12V source terminal and a second 12V source terminal. Other examples are provided below. 
     The MODACS may operate as a low-voltage high-power system. When a safety fault arises in the MODACS, such as a short circuit, or overcharging, a thermal runaway and/or propagation condition may occur. If an abnormal safety fault condition exists with a block of cells, the block of cells may be shutdown to prevent a thermal runaway propagation. When a block overheats, temperatures of adjacent blocks can increase, which can result in additional faults. Another abnormal safety condition that can require a shutdown is an overheat condition, which results in an abnormal heat signal being generated indicating a block of cells is overheating. Safety techniques include disconnecting a block of cells that is suspicious of having a fault from a power grid of the MODACS. The block of cells may then be removed and/or sent to a quality assessment facility to determine (i) whether an issue exists with the block of cells, and (ii) whether the block of cells is serviceable or needs to be replaced. 
     The examples set forth herein include active safety management systems (ASMSs), battery management systems (BMSs), and battery cell monitoring systems and circuits for monitoring gas levels within battery cells during formation of the battery cells and during intended use of the battery cells. During manufacturing of a battery pack, battery cells are assembled and run through multiple operations, tests and checks prior to being put in use. During this process and/or during intended use of the battery cells, gases (e.g., carbon monoxide (CO), carbon dioxide (CO 2 ), hydrogen (H 2 ), ethylene (C 2 H 4 ), and/or methane (CH 4 )) may be generated within the battery cells By monitoring the levels of the gases generated during formation, optimal formation time can be determined, or anomalous cells can be identified. By monitoring the levels of the gases generated during intended use, issues are able to be detected, such as errors in charging, overcharging events, over-discharging events, thermal runaway events, battery aging etc. This is described in further detail below. 
     The examples disclosed herein are applied to vehicle and non-vehicle implementations. The examples are applicable to internal combustion engine (ICE) vehicles, fully electric vehicles, battery electric vehicles (BEVs), hybrid electric vehicles including plug-in hybrid electric vehicles (PHEVs), partially or fully autonomous vehicles, and other types of vehicles including a MODACS for improved fuel economy and other advantages. The examples are also applicable to, for example, electric bikes, network devices, portable electronic devices (e.g., mobile phones, wearable devices, laptop computers, etc.), computers, stationary and mobile power storage devices, and various other devices. 
     The following  FIGS.  1 - 6    show example systems, devices and vehicles in which the ASMSs, BMSs, and battery cell monitoring systems and circuits disclosed herein may be applied. The ASMSs, BMSs, and battery cell monitoring systems and circuits may be applied to other systems that utilize battery cells. 
       FIG.  1    shows an example apparatus  10  including power source gas monitoring circuits. The apparatus  10  may be a vehicle, a network device, a portable electronic device, a bike, or other apparatus. The apparatus  10  may include a control module  12 , a memory  14 , one or more loads  16  and a power source  18 . The power source  18  may include one or more battery packs  20  and one or more gas monitoring circuits  22 . The control module  12  may supply power from the power source  18  to the loads  16 , as shown and/or may control transfer of power directly from the power source  18  to the loads  16 . The control module  12  may include an ASM module  24 , as further described below. The gas monitoring circuits  22  may be included in the battery packs  20  or may be separate from and monitor the battery packs  20 . Various examples of battery packs, battery cells and gas monitoring circuits are shown and described below and are applicable to this embodiment. The loads  16  may include any electronic device drawing electrical current, such as lights, a display, an electronic and/or electrical circuit, a motor, a compressor, a pump, an actuator, etc. 
       FIG.  2    shows an example powertrain system  100  of a vehicle that includes an engine  102 . The vehicle may be non-autonomous, partially autonomous or fully autonomous. The engine  102  includes an intake system  108 , an intake manifold  110  and a throttle valve  112 . An engine (or vehicle) control module (ECM)  114  controls a throttle actuator module  116 . The engine includes one or more cylinders  118 , which may be selectively deactivated by the ECM  114  via a cylinder actuator module  120 . The cylinder  118  has an intake valve  122 . The ECM  114  controls a fuel actuator module  124 , which regulates fuel injection to achieve a desired air/fuel ratio. The engine  102  may be a spark-ignition engine, in which case a spark actuator module  126  energizes a spark plug  128  in the cylinder  118  based on a signal from the ECM  114 , which ignites the air/fuel mixture. The engine  102  may be a homogenous charge compression ignition (HCCI) engine, which performs both compression ignition and spark ignition, or other type of engine. 
     The engine  102  may further have an exhaust valve  130  and an exhaust system  134 . The intake valve  122  may be controlled by an intake camshaft  140 , while the exhaust valve  130  may be controlled by an exhaust camshaft  142 . The engine  102  may further include an intake cam phaser  148  and an exhaust cam phaser  150 . A phaser actuator module  158  may control the intake cam phaser  148  and the exhaust cam phaser  150 . 
     The engine  102  may include a turbocharger turbine  160 - 1 , a turbocharger compressor  160 - 2  a waste gate  162 , and an exhaust gas recirculation (EGR) valve  170 . The EGR valve  170  may be controlled by an EGR actuator module  172 . The engine  102  may further include a crankshaft position sensor  180 , an engine coolant temperature (ECT) sensor  182 , a manifold absolute pressure (MAP) sensor  184 , a mass air flow (MAF) sensor  186 , one or more throttle position sensors (TPS)  190 , an intake air temperature (IAT) sensor  192  and/or one or more other sensors  193 . 
     The ECM  114  may communicate with a transmission control module  194 , for example, to coordinate engine operation with gear shifts in a transmission  195 . The ECM  114  may communicate with a hybrid control module  196 , for example, to coordinate operation of the engine  102  and an electric motor  198 . While the example of one electric motor is provided, multiple electric motors may be implemented. The electric motor  198  may be a permanent magnet electric motor or another suitable type of electric motor that outputs voltage based on back electromagnetic force (EMF) when free spinning, such as a direct current (DC) electric motor or a synchronous electric motor. In various implementations, various functions of the ECM  114 , the transmission control module  194 , and the hybrid control module  196  may be integrated into one or more modules. Under some circumstances, the hybrid control module  196  controls the electric motor  198  to output torque, for example, to supplement engine torque output. The hybrid control module  196  may also control the electric motor  198  to output torque for vehicle propulsion at times when the engine  102  is shut down. 
     The hybrid control module  196  applies electrical power from a MODACS  208  to the electric motor  198  to cause the electric motor  198  to output positive torque. The MODACS  208  is further described below. The electric motor  198  may output torque, for example, to an input shaft of the transmission  195 , to an output shaft of the transmission  195 , or to another component. A clutch  200  may be implemented to couple the electric motor  198  to the transmission  195  and to decouple the electric motor  198  from the transmission  195 . One or more gearing devices may be implemented between an output of the electric motor  198  and an input of the transmission  195  to provide one or more predetermined gear ratios between rotation of the electric motor  198  and rotation of the input of the transmission  195 . In various implementations, the electric motor  198  may be omitted. 
     The ECM  114  starts the engine  102  via a starter motor  202 . The ECM  114  or another suitable module of the vehicle engages the starter motor  202  with the engine  102  for an engine startup event. The ECM  114  may also start the engine in response to an auto-start command during an auto-stop/start event or to an engine start command for a sailing event. A starter actuator module  204  controls the starter motor actuator and the starter motor  202  based on signals from a starter control module, as discussed further below. In various implementations, the starter motor  202  may be maintained in engagement with the engine  102 . The starter motor  202  draws power from the MODACS  208  to start the engine  102 . 
     A generator  206  converts mechanical energy of the engine  102  into alternating current (AC) power. For example, the generator  206  may be coupled to the crankshaft (e.g., via gears or a belt) and convert mechanical energy of the engine  102  into AC power by applying a load to the crankshaft. The generator  206  rectifies the AC power into DC power and stores the DC power in the MODACS  208 . Alternatively, a rectifier that is external to the generator  206  may be implemented to convert the AC power into DC power. The generator  206  may be, for example, an alternator. In various implementations, such as in the case of a belt alternator starter (BAS), the starter motor  202  and the generator  206  may be implemented together. 
     A MODACS control module  240  may be attached to, implemented in or be connected externally to the housing of the MODACS  208 . Example MODACS and MODACS control modules are shown in  FIGS.  3 ,  6 - 7  and  24   . The MODACS control module  240  may be implemented partially or fully at the housing or at a remote location. As an example, the MODACS control module  240  may be implemented as a control module within a vehicle and/or as part of a vehicle control module. 
     The housing of the MODACS  208  may include gas monitoring circuits  243 , switches and battery monitoring (or management) system (BMS) modules, examples of which are shown in  FIGS.  23 - 24   . Examples of the gas monitoring circuits  243  are shown in  FIGS.  9 - 19   . The switches and BMS modules may be connected to, implemented in, and/or implemented separate from the cells of the MODACS  208 . The BMS modules may include gas monitoring circuits and/or sensors. 
     The MODACS control module  240  controls operating states of the switches to connect selected ones of the cells to the source terminals based on information from the BMS modules. Any number of the cells, blocks and/or battery modules may be selected and connected to each of the source terminals at any moment in time. The cells, blocks and battery modules may be connected: in series and/or in parallel; in different connected configurations; and may be organized into blocks, packs, and/or groups. Each block may include one or more cells, which may be connected in series and/or in parallel. Each pack may include one or more blocks, which may be connected in series and/or in parallel. Each group may include one or more packs, which may be connected in series and/or in parallel. The groups may be connected in series and/or in parallel. A battery module may refer to one or more packs and/or one or more groups. 
     Each of the BMS modules may be assigned to one or more cells, one or more blocks, one or more packs, and/or one or more groups and monitor corresponding parameters, such as voltages, temperatures, current levels, SOXs, instantaneous power and/or current limits, short-term power and/or current limits, continuous power and/or current limits, and/or gas levels of gases within the cells. Gas levels within individual cells, blocks, packs, and/or groups may be monitored. 
     The acronym “SOX” refers to a state of charge (SOC), a state of health (SOH), state of power (SOP), and/or a state of function (SOF). The SOC of a cell, pack and/or group may refer to the voltage, current and/or amount of available power stored in the cell, pack and/or group. The SOH of a cell, pack and/or group may refer to: the age (or operating hours); whether there is a short circuit; whether there is a loose wire or bad connection; temperatures, voltages, power levels, and/or current levels supplied to or sourced from the cell, pack and/or group during certain operating conditions; and/or other parameters describing the health of the cell, pack and/or group. The SOF of a cell, pack and/or group may refer to a current temperature, voltage, and/or current level supplied to or sourced from the cell, pack and/or group, and/or other parameters describing a current functional state of the cell, pack and/or group. 
     Instantaneous power and current limits may refer to power and current limits for a short period of time (e.g., less than 2 seconds). Short term power and current limits may refer to power and current limits for an intermediate length of time (e.g., 2-3 seconds). Continuous power and current limits refer to power and current limits for an extended period of time (e.g., periods greater than 3 seconds). 
     A MODACS control module  240  controls the states of the switches to connect the cells to the source terminals while satisfying target and/or requested voltages, currents and power capacities. The MODACS control module  240  and/or a vehicle control module may set the target and/or requested voltages, currents and power capacities, for example, based on a mode of operation. The MODACS  208  may operate in different operating modes, which correspond to vehicle operating modes, as described below. The MODACS operating modes may include, for example, a regenerative mode, a boost mode, an auto start mode, or other MODACS charge or discharge modes. The vehicle operating modes may include an electric vehicle launch mode, an engine start mode, an engine assist mode, an opportunity charging mode, a deceleration fuel cut-off (DFCO) regenerative mode, an electric vehicle regenerative mode (e.g., a generator DFCO regenerative mode or a brake regenerative mode), an electric vehicle cruise mode, and/or other vehicle operating mode. Additional vehicle operating modes are described below. Each of the vehicle operating modes corresponds to one of the MODACS modes. The stated modes are further described below. 
       FIG.  3    shows a MODACS  208  that may be implemented as a single battery having multiple source terminals. Three example source terminals  210 ,  214 ,  216  are shown, although any number of source terminals may be included. The source terminals, which may be referred to as positive output terminals, provide respective direct current (DC) operating voltages. The MODACS  208  may include only one negative terminal or may include a negative terminal for each source terminal. For example only, the MODACS  208  may have a first positive (e.g., 48 Volt (V)) terminal  210 , a first negative terminal  212 , a second positive (e.g., a first 12V) terminal  214 , a third positive (e.g., a second 12V) terminal  216 , and a second negative terminal  220 . While the example of the MODACS  208  having a 48V operating voltage and two 12V operating voltages is provided, the MODACS  208  may have one or more other operating voltages, such as only two 12V operating voltages, only two 48V operating voltages, two 48V operating voltages and a 12V operating voltage, or a combination of two or more other suitable operating voltages. As another example, the operating voltages may range from 12V-144V. 
     The MODACS  208  includes cells and/or blocks of cells, such as a first block (or string)  224 - 1  to an N-th block (or string)  224 -N (“blocks  224 ”), where N is an integer greater than or equal to 2. Each of the blocks  224  may include one or more cells. Each block may also be separately replaceable within the MODACS  208 . For example only, each of the blocks  224  may be an individually housed 12V DC battery. The ability to individually replace the blocks  224  may enable the MODACS  208  to include a shorter warranty period and have a lower warranty cost. The blocks  224  are also individually isolatable, for example, in the event of a fault in a block. In various implementations, the MODACS  208  may have the form factor of a standard automotive grade 12V battery. 
     Each of the blocks  224  has its own separate capacity (e.g., in amp hours, Ah). The MODACS  208  includes switches, such as first switches  232 - 1  to  232 -N (collectively “switches  232 ”). The switches  232  enable the blocks  224  to be connected in series, parallel, or combinations of series and parallel to provide desired output voltages and capacities at the output terminals. Although examples of some switches are shown, other switches may be included to perform the various operations disclosed herein. 
     A MODACS control module  240  includes an ASM module  241  and may control the switches  232  to provide desired output voltages and capacities at the source terminals. The MODACS control module  240  controls the switches  232  to vary the capacity provided at the source terminals based on a present operating mode of the vehicle, as discussed further below. The ASM module  241  may also control the stated switches  232  to disconnect, isolate, test and/or reconnect blocks of cells from the power grid, which includes the other blocks of cells, source terminals, negative terminals, etc. Operations of the ASM module  241  are further described below. 
       FIGS.  4 A- 4 B  show a vehicle electrical system  300  including an example implementation of the MODACS  208 . The MODACS  208  includes the source terminals  210 ,  214 ,  216 , respective power rails  301 ,  302 ,  303 , a MODACS control module  240 , and a power control circuit  305 , which may be connected to the MODACS control module  240  and vehicle control module (VCM) and/or BCM  306 . The VCM and/or BCM  306  may operate similar as, include and/or be implemented as the ECM  114  of  FIG.  6   . Power rail  303  may be a redundant power rail and/or used for different loads than the power rail  302 . The MODACS control module  240  including the ASM module  241 , the power control circuit  305 , the VCM and/or the BCM  306  may communicate with each other via a controller area network (CAN), a local interconnect network (LIN), a serial network, wirelessly and/or another suitable network and/or interface. The MODACS control module  240  may communicate with the VCM and/or BCM  306  directly or indirectly via the power control circuit  305  as shown. 
     In the example of  FIG.  4 A , sets of 4 of the blocks  224  (e.g., 12V blocks) are connectable in series (via ones of the switches  232 ) to the first positive terminal  210  and the first negative terminal  212  to provide a first output voltage (e.g., 48V). Individual ones of the blocks  224  may be connected (via ones of the switches  232 ) to the second positive terminal  214  or the third positive terminal  216  and the second negative terminal  220  to provide a second output voltage (e.g., 12V) at the second and third positive terminals  214  and  216 . How many of the blocks  224  are connected to the first positive terminal  210 , the second positive terminal  214 , and the third positive terminal  216  dictates the portions of the overall capacity of the MODACS  208  available at each of the positive terminals. Any number of the blocks may be connected in series and any number of series sets may be connected in parallel. In the example of  FIG.  4 A , the blocks  224  are shown with battery symbols. Each block may include, as an example, four cells, where each cell is connected in series and is a lithium ion cell (e.g., a lithium iron battery (LFP) cell with a nominal voltage at 3.2V). 
     As shown in  FIG.  4 B , a first set of vehicle electrical components operates using one of the two or more operating voltages of the MODACS  208 . For example, the first set of vehicle electrical components may be connected to the second and third positive terminals  214  and  216 . Some of the first set of vehicle electrical components may be connected to the second positive terminal  214 , and some of the first set of vehicle electrical components may be connected to the third positive terminal  216 . The first set of vehicle electrical components may include, for example but not limited to, the VCM and/or BCM  306  and other control modules of the vehicle, the starter motor  202 , and/or other electrical loads, such as first 12V loads  307 , second 12V loads  308 , other control modules  312 , third 12V loads  316 , and fourth 12V loads  320 . In various implementations, a switching device  324  may be connected to both of the first and second positive terminals  214 . The switching device  324  may connect the other control modules  312  and the third 12V loads  316  to the second positive terminal  214  or the third positive terminal  216 . 
     As shown in  FIG.  4 A , a second set of vehicle electrical components operates using another one of the two or more operating voltages of the MODACS  208 . For example, the second set of vehicle electrical components may be connected to the first positive terminal  210 . The second set of vehicle electrical components may include, for example but not limited to, the generator  206  and various electrical loads, such as 48V loads  328 . The generator  206  may be controlled to recharge the MODACS  208 . 
     Each of the switches  232  may be an insulated gate bipolar transistor (IGBT), a field effect transistor (FET), such as a metal oxide semiconductor FET (MOSFET), or another suitable type of switch. 
       FIG.  5    shows an example of another vehicle control system  400  that is applicable to the MODACSs disclosed herein. The vehicle control system  400  includes a MODACS  402 , a vehicle control module  404 , an internal combustion engine (ICE)  406 , high-voltage loads  408 , and low-voltage loads  410 . The vehicle control module  404  may operate similarly as the other vehicle control modules referred to herein and may include the ASM module  241 . The high-voltage loads  408  may include electric motors, compressors, and/or other high-voltage loads. The low-voltage loads may include lights, seat heaters, electric fans, audio system, video system, power window motors, power door lock motors, electronic circuits, etc. The MODACS  402  has a housing  420  and includes a MODACS control module  422 , a first source terminal  424 , a second source terminal  426  and a negative (or reference ground) terminal  428 . The MODACS  402  may have any number of source terminals. 
     The ICE  406  may drive a water pump  430  via pulleys  431 ,  432  and belt  434 . The ICE  406  may drive a main gear  436 , which drives a clutches C 1 , C 2  and a transmission  438  to drive wheels  440  via a differential  442 . The first clutch C 1  may be used to engage pulleys  444 ,  446  and belt  448 , which drive a motor generator unit (MGU)  450 . The second clutch C 2  may be used to engage the transmission  438 . An AC-to-DC converter  452  converts alternating current (AC) power from the MGU  450  to DC power, which is used to charge the cells of the MODACS  402 . The main gear  436  may be turned by a second gear  454  via a starter  456  when cranking the ICE  406 . 
       FIG.  6    shows a vehicle  500  illustrating another example implementation of a MODACS, which may replace and/or operate similarly as the MODACS  208  and  402  of  FIGS.  2 - 5   . The vehicle  500  may include a MODACS  502  with a MODACS control module  503  and gas monitoring circuits  507 , a vehicle control module  504 , an infotainment module  506  and other control modules  508 . The gas monitoring circuits  507  may be implemented as part of the MODACs  502  or separate from the MODACS  502 . Various example implementations of the gas monitoring circuits  507  are described herein and are applicable to the embodiment of  FIG.  6   , as well as to at least the embodiments of  FIGS.  1 - 5   . 
     The modules  503 ,  504 ,  506 ,  508  may communicate with each other via one or more buses  510 , such as a controller area network (CAN) bus and/or other suitable interfaces. The vehicle control module  504  may control operation of vehicles systems. The vehicle control module  504  may include a mode selection module  512 , a parameter adjustment module  514 , as well as other modules. The mode selection module  512  may select a vehicle operating mode, such as one of the vehicle operating modes stated above. The parameter adjustment module  514  may be used to adjust parameters of the vehicle  500 . 
     The vehicle  500  may further include: a memory  518 ; a display  520 ; an audio system  522 ; one or more transceivers  523  including sensors  526 ; and a navigation system  527  including a global positioning system (GPS) receiver  528 . The sensors  526  may include sensors, cameras, objection detection sensors, temperature sensors, accelerometers, vehicle velocity sensor, and/or other sensors. The GPS receiver  528  may provide vehicle velocity and/or direction (or heading) of the vehicle and/or global clock timing information. 
     The memory  518  may store sensor data  530  and/or vehicle parameters  532 , MODACS parameters  534 , and applications  536 . The applications  536  may include applications executed by the modules  503 ,  504 ,  506 ,  508 . Although the memory  518  and the vehicle control module  504  are shown as separate devices, the memory  518  and the vehicle control module  504  may be implemented as a single device. 
     The vehicle control module  504  may control operation of an engine  540 , a converter/generator  542 , a transmission  544 , a window/door system  550 , a lighting system  552 , a seating system  554 , a mirror system  556 , a brake system  558 , electric motors  560  and/or a steering system  562  according to parameters set by the modules  503 ,  504 ,  506 ,  508 . The vehicle control module  504  may set some of the parameters based on signals received from the sensors  526 . The vehicle control module  504  may receive power from the MODACS  502 , which may be provided to the engine  540 , the converter/generator  542 , the transmission  544 , the window/door system  550 , the lighting system  552 , the seating system  554 , the mirror system  556 , the brake system  558 , the electric motors  560  and/or the steering system  562 , etc. Some of the vehicle control operations may include unlocking doors of the window/door system  550 , enabling fuel and spark of the engine  540 , starting the electric motors  560 , powering any of the systems  550 ,  552 ,  554 ,  556 ,  558 ,  562 , and/or performing other operations as are further described herein. 
     The engine  540 , the converter/generator  542 , the transmission  544 , the window/door system  550 , the lighting system  552 , the seating system  554 , the mirror system  556 , the brake system  558 , the electric motors  560  and/or the steering system  562  may include actuators controlled by the vehicle control module  504  to, for example, adjust fuel, spark, air flow, steering wheel angle, throttle position, pedal position, door locks, window position, seat angles, etc. This control may be based on the outputs of the sensors  526 , the navigation system  527 , the GPS receiver  528  and the above-stated data and information stored in the memory  518 . 
     The vehicle control module  504  may determine various parameters including a vehicle speed, an engine speed, an engine torque, a gear state, an accelerometer position, a brake pedal position, an amount of regenerative (charge) power, an amount of boost (discharge) power, an amount of auto start/stop discharge power, and/or other information, such as priority levels of source terminals of the MODACS  502 , power, current and voltage demands for each source terminal, etc. The vehicle control module  504  may share this information and the vehicle operating mode with the MODACS control module  503 . The MODACS control module  503  may determine other parameters, such as: an amount of charge power at each source terminal; an amount of discharge power at each source terminal; maximum and minimum voltages at source terminals; maximum and minimum voltages at power rails, cells, blocks, packs, and/or groups; SOX values cells, blocks, packs, and/or groups; temperatures of cells, blocks, packs, and/or groups; current values of cells, blocks, packs, and/or groups; power values cells, blocks, packs, and/or groups; etc. The MODACS control module  503  may determine connected configurations of the cells and corresponding switch states as described herein based on the parameters determined by the vehicle control module  504  and/or the MODACS control module  503 . 
     The vehicle  500  includes an ASM system  570 , which includes the ASM module  241 , the MODACS  502 , and the MODACS control module  503 . Although shown in the vehicle control module  504 , the ASM module  241  may be included in the MODACS control module  503 . In one embodiment, the vehicle control module  504  and the MODACS control module  503  are implemented as a single control module. 
     The following examples of  FIGS.  7 - 25 C  are applicable to all of the above-described examples of  FIGS.  1 - 6   . 
       FIG.  7    shows an electrode stack  600  and tabs  602 ,  604  of a battery cell. The electrode stack  600  include multiple anode electrode layers, cathode electrode layers, and separation layers disposed between the anode electrode layers and the cathode electrode layers. One of the tabs  602 ,  604  may be connected to the anode electrodes of the electrode stack  600  and the other one of the tabs  602 ,  604  may be connected to the cathode electrodes of the electrode stack  600 . 
       FIG.  8    shows a sealed battery case  700  for the electrode stack  600  of  FIG.  7    to provide a battery cell. The electrode stack  600  is disposed in the case  700  including upper and lower layers that are sealed along a periphery of the case  700  to form a peripheral seal  702 . The peripheral seal extends around a perimeter of the electrode stack  600 . The tabs  602 ,  604  extend from the electrode stack  600  through the peripheral seal and out of the case  700 . The battery cell may be configured as any of the battery cells disclosed herein. Although not shown in  FIG.  8   , the battery cell may include a gas monitoring circuit disposed within or attached to the case  700 . Also, although not shown in  FIG.  8   , the battery cell may include a gas sensor disposed within or attached to the case  700 . Gas monitoring circuit and gas sensor arrangements are further described below with respect to  FIGS.  11 - 19   . 
       FIG.  9    shows serially connected battery cells  800 ,  802  and corresponding modules (or blocks) of battery cells, such as the battery cell shown in  FIG.  8   . The opposing tabs (e.g., tabs  804 ,  806 ) of the battery cells  800 ,  802  are connected to provide a chain of battery cells. This is done multiple times to form multiple blocks  808  of battery cells.  FIG.  10    shows a battery pack  900  including modules (or blocks) of battery cells (e.g., blocks of battery cells  902 ,  904 ). This may include the blocks  808  of  FIG.  9   . 
       FIG.  11    shows an example battery cell  1000  including wireless gas monitoring circuit  1002 . The cell  1000  includes a case (or pouch)  1004 . The gas monitoring circuit  1002  may be disposed within the case  1004  along with an electrode stack  1006 . The battery cell  1000  and other battery cells referred to herein may be in the form of a pouch cell, a prismatic cell, a cylindrical cell, etc. The case  1004  may be under vacuum when sealed such that layers of the case conform to shapes of the gas monitoring circuit  1002  and the electrode stack as shown by box  1010 . The electrode stack  1006  includes an anode terminal (or tab)  1012  and a cathode terminal (or tab)  1014 . 
     The gas monitoring circuit  1002  monitors gas levels of one or more gases within the case  1004 . The gas monitoring circuit  1002  may include any number of gas sensors. An example of a gas monitoring circuit that may replace the gas monitoring circuit  1002  is shown in  FIG.  15   . The gas monitoring circuit may wirelessly communicate with any of the ASM modules, BSM modules, and control modules referred to herein. This may include the transfer of sensor data from sensors on the gas monitoring circuit  1002 . The gas monitoring circuit  1002  may be powered via a power source external to the gas monitoring circuit  1002  or may include, for example, a rechargeable battery, which may be connected to the gas monitoring circuit  1002 . In one embodiment, the gas monitoring circuit  1002  is not powered by the electrode stack  1006 . This assures that operation of the gas monitoring circuit  1002  is not affected by power output of the electrode stack  1006 . 
     The gas monitoring circuit  1002  and/or gas sensors, as further described, herein may be fixed to, embedded in and/or removable from the case  1004 . The gas monitoring circuit  1002  and the gas sensors may be stand-alone devices outside of the case  1004  or may be attached to and/or included in the case  1004 . When fixed, the gas monitoring circuit  1002  and/or sensors may be coated and/or adhered to the case  1004 . The gas monitoring circuit  1002  may record sensor data and other data and be removable, such that a direct connection can be made to the gas monitoring circuit  1002  to extract the saved data. The gas monitoring circuit  1002  may be tunable, such that selected sensors are on a given moment in time and for a given operation being performed. 
       FIG.  12    shows a battery cell  1100  including a wired gas monitoring circuit  1102 . The cell  1100  includes a case (or pouch)  1104 . The gas monitoring circuit  1102  may be disposed within the case  1104  along with an electrode stack  1106 . The case  1104  may be under vacuum when sealed such that layers of the case conform to shapes of the gas monitoring circuit  1102  and the electrode stack as shown by box  1110 . The electrode stack  1106  includes an anode terminal (or tab)  1112  and a cathode terminal (or tab)  1114 . 
     The gas monitoring circuit  1102  monitors gas levels of one or more gases within the case  1104 . The gas monitoring circuit  1102  may be configured similarly as the gas monitoring circuit  1002  of  FIG.  11    and may implement wired communication with any of the ASM modules, BSM modules, and control modules referred to herein. This communication may be implemented via a cable  1105  (e.g., a universal serial bus (USB) cable, or other suitable cable and/or set of one or more wires. This may include the transfer of sensor data from sensors on the gas monitoring circuit  1102 . The gas monitoring circuit  1102  may be powered via a power source external to the gas monitoring circuit  1002  or may include, for example, a rechargeable battery, which may be connected to the gas monitoring circuit  1102 . In one embodiment, the gas monitoring circuit  1102  is not powered by an electrode stack  1106 . This assures that operation of the gas monitoring circuit  1102  is not affected by power output of the electrode stack  1106 . 
       FIG.  13    shows a battery cell monitoring system  1200  including a formation monitor  1202 . The formation monitor  1202  may be implemented as a computer and may test and monitor states of a battery cell  1204 . The battery cell monitoring system  1200  may further include a cycler  1206  attached to tabs  1208 ,  1210  of an electrode stack  1212  of the battery cell  1204  via connectors  1214 ,  1216 . A voltage sensor  1220  and a current sensor  1222  may be used to monitor a voltage across the tabs  1208 ,  1210  and a level of current through the electrode stack  1212 . The cycler implements charge and discharge cycles of the electrode stack  1212 . This cycling of the electrode stack between charged and discharged states may be controlled and monitored by a control module  1224  of the formation monitor  1202 . In one embodiment, the formation monitor  1202  includes the gas monitoring circuit  1236 . 
     The battery cell  1204  may be connected to and/or include one or more sensors. The sensors may be disposed within a case  1230  of the battery cell  1204 , as shown by the sensor(s)  1232 , or external to the battery cell  1204 , as shown by the sensor(s)  1234 . Although the gas monitoring circuit  1236  is shown separate from the battery cell  1204  and the sensors, the gas monitoring circuit  1236  may include the sensors and/or be disposed within and/or attached to the battery cell  1204 . In one embodiment, the sensor(s)  1234  are connected to the case  1230  via one or more capillaries, an example capillary  1240  is shown. Gas is passed through the capillary and detected by a sensor on the gas monitoring circuit  1236 . The sensors  1232 ,  1234  includes one or more gas sensors. The gas sensors  1234  and/or the capillary  1240  may be connected to the case  1230  via a connector  1241  (e.g., a quick disconnect connector). The gas monitoring circuit  1236  may be configured the same or similarly as any of the other gas monitoring circuits disclosed herein. In one embodiment, sensors are provided such that the control module  1224  is able to monitor the parameters monitored by the BMS module of  FIG.  23   . 
     Although the sensors  1234  and the gas monitoring circuit  1236  are shown separate from the case  1230  for a formation process, this arrangement may also be used for other battery cell implementations, such as in a MODACS. The sensors  1234  may be directly connected to the case  1230  without use of a capillary. See, for example,  FIG.  18   . 
     The battery cell  1204  may be held at least partially in a fixture  1250 . The fixture  1250  may include opposing plates that are used to apply pressure on the battery cell  1204  and the electrode stack  1212 . As an example, the plates may be fastened to each other via fasteners, which may be torqued down to apply pressure on the electrode stack  1212 . Pressure may be applied to assure that the electrode stack  1212  is performing appropriately. Different pressures may be applied for different electrode stack chemistries. The pressures applied may be the same as pressures applied when implemented in a battery pack and/or in a MODACS. 
     The control module  1224  and/or the gas monitoring circuit  1236  may detect when an error or issue exists based on gas levels detected via the sensors  1232 ,  1234  and/or outputs of the sensors  1220 ,  1222 . The stated sensors  1220 ,  1222 ,  1232 ,  1234 , are monitored during formation, checking and/or testing of the battery cell  1204 . The monitored information may also be used to provide sensor-assisted control of the formation process including modifying a formation protocol. As an example, a gas signal from one of the gas sensors may be monitored and be indicative of cell formation operation completion and/or cell formation completion. In response, the control module  1224  may end a formation operation and/or operations to avoid any excess time spent during formation. As a result, a fixed time protocol is not used and the duration of formation is reduced. This decrease an overall formation process time. 
     Gas levels may be monitored for quality control and battery safety reasons. When an issue is detected, the control module  1224  may trigger an alarm and cease charging the electrode stack  1212  if operating in a charging mode. This prevents overcharging the electrode stack  1212 . As an example, when an amount (or gas level) of CO 2  is greater than a set threshold, then overcharging may be occurring. As another example, when a gas level exceeds a predetermined threshold, the potential of a thermal runaway event increases. Thus, to prevent a thermal runaway condition, charging of the electrode stack  1212  may be ceased. Gas formation is based on chemistries of electrodes and surrounding materials and operations being performed. 
       FIG.  14    shows an electrode stack  1300  that includes anode current collector layers (or anode electrodes)  1302 , cathode current collector layers (or cathode electrodes)  1304  and separator layers  1306 . The electrode stack  1300  is provided as an example of the other electrode stacks disclosed herein. 
     The anode electrodes  1302  may be formed of graphite, silicon (Si), silicon oxide (SiO x ), a lithium metal material, etc. and combinations thereof. The cathode electrodes  1304  may be formed of nickel manganese cobalt (NMC), nickel cobalt aluminum LiNixCoyAlzO2 NCA, nickel cobalt manganese aluminum (NCMA), lithium manganese oxide LiMn2O 4  LMO, lithium manganese nickel oxide (LMNO), lithium cobaltate LiCoO2 (LCO), lithium iron phosphate LiFePO4 (LFP), lithium manganese iron phosphates (LMFP), LLC, etc. The separator layers include one or more electrolytes, such as a carbonate based electrolyte, a fluorinated electrolyte and/or other suitable electrolyte. 
       FIG.  15    shows an example gas monitoring circuit  1400  that may include a power source  1402 , a control module  1404 , a transceiver  1406  a memory  1408  and one or more gas sensors  1410 . Although not shown in  FIG.  15   , other sensors, such as voltage and/or current sensors may be included for monitoring voltage across terminals of an electrode stack and/or current through the electrode stack. The memory  1408  provides on-site storage and stores the data collected from the sensors and/or data generated based on the data collected from the sensors. 
     The power source  1402  may include a battery, one or more capacitors, and/or power source terminals. In one embodiment, the power source  1402  receives power from a remote power source via the connector  1420  and does not include a battery. 
     The control module  1404 , based on outputs of the sensors may determine gas levels within a cell, voltages across terminals of the cell, current levels through an electrode stack of the cell, and/or resistances (e.g., a direct current resistance) of the electrode stack. As an example, the gas monitoring circuit  1400  may include a connector for wired communication and/or to receive power. The connector  1420  may be a USB connector. In an embodiment, the gas monitoring circuit  1400  wirelessly communicates with an ASM module, a BSM module, a control module, a central monitoring station, a formation monitor (e.g., the formation monitor  1202  of  FIG.  13   ), or other monitoring module or device. This communication may include sharing of the data stored in the memory  1408 . 
     The transceiver  1406  may be a wired or wireless transceiver and have an antenna  1422 . The transceiver may be configured to communicate with various network devices, such as the transceivers  523  of  FIG.  5   , the formation monitor  1202  of  FIG.  13   , a remotely located monitoring device at a central station, and/or other network devices. As an example, the transceiver may operate according Bluetooth® communication protocols. In one embodiment, the transceiver  1406  may wirelessly communicates with one of the transceivers  523  of  FIG.  6   . In one embodiment, each battery cell within the MODACs  502  of  FIG.  6    includes a gas monitoring circuit that is implemented the same or similarly as the gas monitoring circuit  1400  of  FIG.  15   . 
       FIG.  16    shows serially connected gas sensors  1500  of a battery cell, such as one of the battery cells of  FIGS.  7 - 13   . The gas sensors  1500  are connected in series, such that when power having a voltage V CC  is supplied to one of the gas sensors  1500 , power is supplied to all of the gas sensors  1500 . As an example, the gas sensors  1410  of  FIG.  15    may include the gas sensors  1500  and the control module  1404  may control the powering of the gas sensors  1500 . The control module  1404  may monitor changes in output voltages V CR1 , V CR2 , V CR3  of the sensors  1500 , which may be based on chemical resistance changes of materials of the gas sensors  1500 . As an example, the gas sensors  1500  may include chemical resistors for single or multiple gas detection by each of the sensors  1500 . 
       FIG.  17    shows parallel and serially connected gas sensors  1600 ,  1602 ,  1604  of a battery cell including tuning switches  1606 ,  1608 ,  1610 . In an embodiment, the switches  1606 ,  1608 ,  1610  are implemented as transistors, which may be part of one of the gas monitoring circuits disclosed herein or connected separate from the corresponding gas monitoring circuit. 
     In this arrangement, the gas sensors  1600 ,  1602  may be powered alone or in combination with the gas sensor  1604 . Similarly, the gas sensors  1604  may be powered alone or in combination with the gas sensors  1600 ,  1602 . As an example, the gas sensors  1410  of  FIG.  15    may include the gas sensors  1600 ,  1602 ,  1604  and the control module  1404  may control the state of the switches  1606 ,  1608 ,  1610  to control the powering of the gas sensors  1600 ,  1602 ,  1604 . A voltage V CC  may be supplied to one or more of the gas sensors  1600 ,  1602 ,  1604 . In one embodiment, one of the switches  1608 ,  1610  is not included. The outputs of the sensors  1600 ,  1602 ,  1604  is represented as V CR1 , V CR2 , V CR3 , which may be based on chemical resistance changes of materials of the gas sensors  1600 ,  1602 ,  1604 . The ability to select which gas sensor is active provides tunability via the switches  1606 ,  1608 ,  1610  and flexibility in the use of certain sensors during certain periods of time and/or under certain operating conditions. This also minimizes power consumed by the sensors. As an example, the gas sensors  1600 ,  1602 ,  1604  may include chemical resistors for single or multiple gas detection by each of the sensors  1600 ,  1602 ,  1604 . Although three gas sensors and three switches are shown, any number of gas sensors and switches may be included and arranged in various serial and parallel arrangements. 
     Gas sensors and/or the gas monitoring circuits may be placed in or near battery cells to detect and monitor gas levels.  FIG.  18    shows a battery cell  1700  including a gas sensor  1702 . The battery cell  1700  includes a case  1704  that is vacuum fit over an electrode stack  1706 . The gas sensor  1702  is adhered to the case  1704  via an adhesive layer  1708 . A hole  1710  exists in the case  1704  that allows gas within the case  1704  to be detected by the gas sensor  1702 . The hole  1710  is aligned with a channel  1712  in the adhesive layer  1708 . The gas sensor  1702  may be connected to a gas monitoring circuit disclosed herein. 
       FIG.  19    shows battery cells  1800  connected to a communication bus bar  1802  and power bus bars  1804 ,  1806 . The power bus bar  1804  may provide a supply voltage and the power bus bar  1806  may be at a ground reference voltage. Each of the battery cells  1800  include respective electrode stacks  1810  and gas monitoring circuits  1812 . The electrode stacks  1810  include terminals  1814 ,  1816 . 
     In one embodiment, the MODACS control module  503 , the ASM module  241  and/or the vehicle control module  504  of  FIG.  6    may monitor gas levels and other parameters of battery cells of the MODACS  502 , which may include the battery cells  1800 . In one embodiment, these parameters are monitored and outliers are flagged and may be isolated and/or further evaluated. As an example, when a gas level of one of the battery cells (an outlier) is significantly higher than gas levels of the other battery cells, then an issue may exist with the outlier. 
       FIG.  20    shows a gas level versus time plot during battery cell formation. The plot is an example of the increase in a gas level within a battery cell during formation of the battery cell. During formation of the battery cell an anode electrode and a cathode electrode may be soaked in an electrolyte material. A formation protocol may include allowing the cathode electrode to stabilize to form a passivated layer. During degassing a lot of gas can be generated. Subsequent to degassing, the electrodes are in a stable state. An example formation method is described with respect to  FIG.  25   . 
       FIG.  21    shows sensor voltage versus time plot for two different gases. A first voltage signal  2000  is shown for a first gas sensor and a second voltage signal  2002  is shown for a second gas sensor. 
       FIG.  22    shows plots of battery cell voltage versus time and ion current versus time during battery cell formation. A voltage signal  2100  of an electrode stack of a cell, a first ion current signal  2102  of a first gas sensor, and a second ion current signal  2104  of a second gas sensor are shown. As an example, the electrode stack may be fully charged when the voltage signal of the electrode stack is at a peak (or maximum voltage). An example peak  2110  is shown. 
     The plots of  FIGS.  21  and  22    are example plots generated during formation of a battery cell. Other gas sensor plots may be generated. Each of the plots and/or one or more sets of the plots may be used to determine whether certain issues and/or conditions exist. Some of these issues and conditions are mentioned above. During formation, when certain cell voltage, gas levels, and/or ion current levels are reached, certain formation steps may be completed. In response to determining that the operations are completed, time spent performing the operations may be decreased by moving on to the next operations and instead of spending any further time performing the previous operations. As another example, when gas levels and/or ion current levels of multiple different gases are at predetermined levels, the battery cell is fully charged. As yet another example, the type and amount of gas generated may indicate whether a thermal runaway is occurring. Example types of gases that may be monitored are stated above. 
     The ASM systems referred to herein actively monitoring cells and instantaneously and/or quickly disconnect, isolate, and/or reevaluate conditions of the cells. The safety fault may be due to an internal short, an overcharging of cells, and/or other safety fault conditions. When a 12V block safety fault (or suspicious) signal (e.g., an over temperature signal, an abnormal rate of change in voltage signal, an abnormal increase an gas pressure, an abnormal rate of change in temperature signal, and/or other irregularity signal) is generated and diagnosed, the ASM system adjusts a working mode of the suspicious block of cells and/or working modes of one or more other blocks of cells. The actions may include disconnecting and/or isolating the suspicious block of cells. In one embodiment, a block of cells may be isolated when a cell of the block of cells is experiencing an issue. 
       FIG.  23    shows an example battery monitoring (or management) system (BMS) module  2200  for a block of cells  2202  including any number of cells and/or blocks. In one embodiment, the battery monitoring system module  2200  is provided for each block of cells as part of an ASM system. In the example shown, the BMS module  2200  monitors voltages, temperatures, gas levels, power levels, and current levels of the corresponding block of cells  2202  and determines certain parameters. The BMS module  2200  may include, be connected to, and/or communicate with one or more gas monitoring circuits (one gas monitoring circuit  2203  is shown) for monitoring gas levels within one or more cells. The gas monitoring circuits may be configured similarly and/or perform similar operations as other gas monitoring circuits disclosed herein. In one embodiment, the BMS module is in communication with multiple gas monitoring circuit, which are located in respective cells. In another embodiment, the BMS module is connected to one or more gas sensors (one gas sensor  2205  is shown). The gas sensors may be connected to or included in one or more cells. 
     The parameters may include instantaneous charge and discharge power and current limits, short term charge and discharge power and current limits, gas level limits and/or thresholds, and continuous charge and discharge power and current limits. The parameters may also include minimum and maximum voltages, minimum and maximum operating temperatures, and SOX limits and/or values. The parameters output by the BMS module  2200  may be determined based on the voltages, temperatures and/or current levels monitored. The charge and discharge power and current capability of a 12V block or pack is affected by the minimum and maximum voltages, minimum and maximum operating temperatures, and SOX limits and/or values of the corresponding cells. The BMS module  2200  may monitor individual cell voltages, temperatures gas levels, and current levels and determine based on this information the stated parameters. The parameters output by the BMS module  2200  are shown as arrow out of the BMS module  2200 . The parameters received by the BMS module  2200  are shown as arrow directed to the BMS module  2200 . The BMS module  2200  may generate safety fault signals when certain safety fault conditions are detected, such as the safety fault conditions referred to herein. 
     As an example, the BMS module  2200  may include and/or be connected to sensors, such as a current sensor  2204 , the gas sensors and a temperature sensor  2206 , which may be used to detect current levels through the cells of block or pack  2202 , gas levels of gases in cells, and temperatures of the block or pack  2202 . As an example, a voltage across the block or pack may be detected as shown. In an embodiment, one or more voltage sensors may be included to detect voltages of the block of cells  2202 . The current sensor  2204  may be connected, for example, between the block of cells  2202  and a source terminal  2208 , which may be connected to a load  2210 . The temperatures, gas levels, voltages, and current levels are reported to the BMS module  2200  and/or the ASM module  241  (shown in  FIGS.  3 - 6  and  24   ) as some of the parameters received by the BMS module  2200 . 
       FIG.  24    shows a portion of a MODACS circuit  2300  that includes one or more source terminals. The MODACS circuit  2300  may include multi-functional solid-state switches, switch drive circuits, current and voltage sense circuits arranged in a minimum switch count topology to enable on-demand capacity allocation for source terminals having similar or dissimilar preset (or target) voltages. The MODACS circuit  2300  is flexible, modular, and has minimum size, complexity, weight, and component count. For at least these reasons, the MODACS circuit  2300  minimizes manufacturing difficulty. 
     As shown, the MODACS circuit  2300  includes block sets, where each block set includes 4 cells, 4 or more switches, a BMS module and source terminals with corresponding power rails. The BMS module may be configured as the BMS module  2200  of  FIG.  23   . The BMS module may be in communication with and/or connected to gas monitoring circuits and/or gas sensors, as described herein. An example block set  2302  is outlined and includes a block of cells  2304 , 4 switches  2306  and a BMS module  2308 . The blocks are shown with battery symbols. Three of the switches  2306  connect the blocks  2304  respectively to source terminals (e.g., a 48V, 12VA, and a 12VB source terminals are shown). The fourth one of the 4 switches  2306  connects the block  2304  to a ground reference (or negative terminal)  2312 . In an embodiment, the gas monitoring circuit of the BMS module monitors gas levels of the cells of the corresponding block of cells (or block set). 
     As shown the blocks may be arranged in an array having rows and columns. Each of the blocks may be configured the same except one of the rows closest to the ground reference. In this row, each of the blocks includes three switches instead of four switches. As a result, the corresponding cells are connected to the ground reference without use of switches, as shown. 
     As can be seen, the blocks may be connected to each of the source terminals. Any block may be connected to any one or more of the source terminals. The first switches in the block sets in one of the rows (or first row) may be connected to the first source terminal (48V source terminal). The first switches in the block sets in one or more intermediate rows (e.g., the second and third rows) may be connected to cell(s) in a previous row. This allows the cell(s) in the blocks in each column to be connected in series. Under certain conditions, the blocks in columns are connected in series to form two or more series of blocks and the multiple series of blocks are connected in parallel to maximize power to the first source terminal. 
     The MODACS circuit  2300  further includes a MODACS control module  240  that controls states of the blocks and includes the ASM module  241 . The MODACS control module  240  receives BMS signals from the BMS modules and a system capacity request signal from a vehicle control module or non-vehicular control module (a control module of a device other than a vehicle). Based on priorities of the voltage source terminals, parameters, and power and current demands indicated by the system capacity request signal, the MODACS control module  240  determines a connected configuration and sets states of the switches of the cells and/or blocks. Additional switches than shown may be included for more selective isolation of cells. The parameters may include voltages, power levels, current levels, gas levels, and temperatures indicated in the BMS signals. The MODACS control module  240  generates an actual capacity allocation signal indicating capacity allocation for the source terminals. The actual capacity allocation may not match the requested capacity allocation depending on: the state of the MODACS including whether there is any faults or shorts; and the SOH of the blocks. The actual capacity allocation signal may be transmitted from the MODACS control module  240  to the vehicle control module or non-vehicular control module. 
     The MODACS circuit  2300  includes a 12V switching matrix, architecture, and switch controls to enable elimination of 12V stabilization using a DC-to-DC converter, such as a 48V to 12V DC-to-DC buck or boost converter, and/or elimination of 12V and/or 48V redundant back-up power. The MODACS circuit  2300  has a minimal circuit, block, switch configuration for one high power, high voltage (e.g., V 1  greater than or equal to 24V) source terminal and at least two low power, low voltage (e.g., two 12V) source terminals. The switches may be solid-state switches for fast noise free reconfiguring. The switches may be configured for bi-directional voltage and current blocking capability to prevent shorts between high and low voltage source terminals. Switches configured for unidirectional voltage and current blocking may be used to minimize losses selectively. 
     The switches may be implemented in a single chip or in a multi-chip package. The switches may include enhancement mode silicon metal-oxide-semiconductor field-effect-transistors (MOSFETs), gallium nitride (GaN) FETs, silicon carbide (SiC) MOSFETS, insulated-gate bipolar transistors (IGBTs), and/or other suitable switches. The switches may be in an ON state, an OFF state, or a linear operating state for impedance matching purposes. The switches may be integrated together with drivers and interlock logic to prevent short circuits between blocks, between different source terminals, and between a source terminal and a ground reference. The switches are controlled to achieve a desired capacity at each source terminal based on control module demands and status updates in the form of feedback signals from the BMS modules of the blocks. 
     In an embodiment, the cells of the blocks are lithium battery cells, but may be other types of cells. The example of  FIG.  24    is shown to illustrate a minimalistic architecture having a minimal number of blocks and switches per block set to provide 48V, 12VA and 12VB outputs without a DC-to-DC converter. 
       FIGS.  25 A-C  illustrates a battery cell formation method. Although the method of  FIG.  25    is described with respect to a single battery cell, the method may be performed for multiple battery cells in parallel. This method may be automated and performed using one or one or more robots, which may be controlled by the control module  1224  of  FIG.  13   . 
     The method may begin at  2400 . At  2402 , a battery cell is assembled. At  2404 , the battery cell is placed in a fixture (e.g., the fixture  1250  of  FIG.  13   ). At  2406 , pressure (e.g., 4-50 pound-force per square inch (psi)) is applied on an exterior of the battery cell. 
     At  2408 , the battery cell is charged to a first predetermined voltage (e.g., 3.9V) at a constant current I 1  (e.g., C/20). A battery cell C rating is the measurement of current in which a battery is charged and discharged. The capacity of a battery (or battery cell) is generally rated and labeled at the 1 C rate (1 C current), which means a fully charged battery (or battery cell) with a capacity of 10 Ampere hours (Ah) should be able to provide 10 Amps for one hour. 
     At  2410 , the first predetermined voltage is maintained and a clock is started. At  2412 , the control module  1224  determines whether a current level of the battery cell has decayed to a second current level I 2  (e.g., C/100). If yes operation  2414  is performed. 
     At  2414 , degassing of the battery cell is performed. At  2414 A, the battery cell is removed from the fixture to begin degassing. At  2414 B, the control module  1224  determines whether degassing is complete. If yes, operation  2416  is performed. This may be determined based on one or more gas levels within a case of the battery cell, as described above. At  2414 C, the control module  1224  monitors one or more gas levels in a case of the battery cell while performing at least operation  2414 . 
     At  2416 , the control module  1224  may cease monitoring the gas levels within the battery cell. 
     At  2418 , the control module  1224  performs a life capacity check of the battery cell. At  2418 A, the battery cell is returned to the fixture and charged to a second predetermined voltage (e.g., upper voltage limit Vmax (e.g., 4.2V)) at the constant current I 1 . At  2418 B, the second predetermined voltage is maintained on the battery cell. At  2418 C, the control module  1224  determines whether a current level of the battery cell has decayed to the second current level I 2 . If yes operation  2418 D is performed. 
     At  2418 D, the control module  1224  permits the voltage on the battery cell to drop to a third predetermined voltage (e.g., a lower voltage limit Vmin (e.g., 2.5V)) while at the constant current level I 1 . 
     At  2418 E, the control module  1224  may monitor the previous one or more gas levels and/or another one or more gas levels in the case of the battery cell while performing at least operation  2418 . 
     At  2420 , an initial resistance check of the battery cell is performed. At  2420 A, the battery cell is charged and discharged at 1 C rate for 2 cycles at a same potential window (e.g., 2.5-4.2V). At  2420 B, the control module  1224  performs a third cycle and during discharge and when at 50% of SOC, applies a 3 C pulse and measures the direct current resistance (DCR). At  2420 C, the control module  1224  charges at 1 C to 50% of SOC. 
     At  2420 D, the control module  1224  may monitor the previous one or more gas levels and/or another one or more gas levels in the case of the battery cell while performing at least operation  2420 . 
     At  2422 , an aging process is performed. At  2422 A, the battery cell is placed in a thermal chamber, which is at a set temperature (e.g., 35° C.). At  2422 B, a first timer is started. At  2422 C, based on the first timer and when the aging period is up, operation  2422 D is performed. As an example, the battery cell may remain in the thermal chamber for a week. 
     At  2422 D, the battery cell is removed from the thermal chamber and/or a temperature of the battery cell is permitted to decrease to room temperature. At  2422 E, a second timer is started. 
     At  2422 F, the control module  1224  may monitor the previous one or more gas levels and/or another one or more gas levels in the case of the battery cell while performing at least operations  2422 A-E. 
     At  2422 G, the control module  1224  may determine whether the second timer is up. As an example, the battery cell may be placed at room temperature for 1 hour. If yes, operation  2422 H and  2422 I are performed. 
     At  2422 H, the control module  1224  measures parameters of the battery cell including a resistance, a voltage, a temperature and/or levels of gases of the battery cell. At  2422 I, the control module ceases monitoring gas levels. 
     At  2424 , the control module  1224  compares voltage, resistance, gas levels, temperature levels, and/or other parameters measured at  2422 H and/or throughout the method of  FIG.  25    to predetermined ranges for performed operations. At  2426 , the control module  1224  determines whether the one or more parameters are outside of predetermined ranges, operation  2428  is performed, otherwise operation  2430  is performed. 
     At  2428 , the battery cell is discarded. At  2430 , the battery cell is not discarded and may be included in a battery pack. The method may end at  2432 . 
     The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure. 
     Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” 
     In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A. 
     In this application, including the definitions below, the term “module” or the term “controller” may be replaced with the term “circuit.” The term “module” may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip. 
     The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module. 
     The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules. 
     The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc). 
     The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer. 
     The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc. 
     The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.