Patent Publication Number: US-2023141841-A1

Title: High voltage battery bypass for electric vehicle fleet

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of and hereby incorporates by reference, for all purposes, the entirety of the contents of U.S. Non-Provisional Application No. 16/825,173, filed Mar. 20, 2020, and entitled “HIGH VOLTAGE BATTERY BYPASS FOR ELECTRIC VEHICLE FLEET”. 
    
    
     TECHNICAL FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to battery-powered electric vehicles fleets and, more specifically, to systems and methods for powering a battery-powered vehicle from a charger while bypassing the battery. 
     BACKGROUND 
     Electric vehicles (EVs) are powered by batteries that need to be periodically charged. Modern direct current (DC) fast-charging electric vehicle chargers can quickly charge EV batteries; for example, a DC fast-charging EV charger may increase the range of an EV by 100 miles in 30 minutes. For fleet operations, EV batteries often fully recharge before the EVs are needed for service, e.g., during night time or other periods of lower demand. In addition, it can be useful to keep some subsystems, such as a communications system, of an EV running while the EV is not in service. If the battery reaches full charge before the EV is put into service again, the subsystems that remain on before service deplete the battery. Then, when the EV is put into service, the battery is no longer fully charged. To avoid this, the EV can continue charging until it is put into service, so that EV has a fully charged battery when it goes into service. However, this continuous charging degrades the battery. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To provide a more complete understanding of the present disclosure and features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying figures, wherein like reference numerals represent like parts, in which: 
         FIG.  1    is a block diagram illustrating a system including an example EV in a fleet of EVs in which powering the EV in a charging bypass mode according to some embodiments of the present disclosure may be implemented; 
         FIG.  2    is a block diagram illustrating a power system for powering various vehicle subsystems according to some embodiments of the present disclosure; 
         FIG.  3    is a block diagram illustrating a fleet management system according to some embodiments of the present disclosure; 
         FIG.  4    is a block diagram illustrating a charging manager according to some embodiments of the present disclosure; and 
         FIG.  5    is a flowchart showing a process for selecting and applying power modes of the EV according to some embodiments of the present disclosure. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE 
     Overview 
     The systems, methods and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described in this specification are set forth in the description below and the accompanying drawings. 
     In current EV fleet management, EV batteries are typically recharged quickly (e.g., at the fastest possible rate for a given EV battery and charging station combination) so that the EVs can return to service. However, oftentimes, an EV is not immediately needed for service after the battery has reached a full charge. For example, if an EV is recharged during a period of low demand (e.g., overnight), the EV may not return to service for several hours (e.g., not until the next morning). For fleet operations, it can be useful to keep some subsystems of the EV running even while the EV is not in service. For example, the EV&#39;s communications system is kept running so that a fleet management system can communicate with the EV, e.g., to transmit instructions to go into service, receive status information, send software upgrades, etc. For autonomous EVs, it can be useful to keep autonomous driving hardware (e.g., sensor systems, processing systems) powered on for routine use and monitoring, and to avoid a lengthy restart procedure before the EV can be put back into service. If the EV is disconnected from the charging station after the battery is charged, continuing to operate these subsystems drains the battery, and the EV does not have a fully charged battery when it goes into service. Leaving the EV connected to the charging station even after the battery has been fully charged ensures that the battery remains fully charged; however, leaving the EV plugged into a charging station that provides more power than needed to run these subsystems degrades the battery. 
     Powering the EV using a charging bypass mode overcomes these problems by enabling the EV to continue to receive power from a charging station without straining the battery. After the battery has reached a full charge, the power distribution module of the EV continues to receive power from the charging station and distribute the power to various subsystems that remain on while the EV is not in service. A battery bypass module causes the power received from the charging station to bypass the battery, so the battery retains its full charge but is not strained by continual charging from the charging station. The charging bypass mode can be selectively engaged and disengaged by a fleet management system, e.g., the fleet management system may instruct an EV to engage the charging bypass mode in response to low demand, or to disengage the charging bypass mode in response to demand by other EVs in the fleet for charging stations. 
     Embodiments of the present disclosure provide a system for powering an electric vehicle (EV) that includes a battery, a power distribution module, and a battery bypass module. The power distribution module is configured to receive power from a charger, draw power from the battery in a discharging mode, distribute power from the charger to the battery in a charging mode, and distribute power to a plurality of subsystems of the EV. The battery bypass module is coupled to the battery and to the power distribution module. The battery bypass module, when engaged in a charging bypass mode, causes power distributed by the power distribution module from the charger to bypass the battery and to be distributed to at least a subset of the plurality of subsystems of the EV. 
     Further embodiments of the present disclosure provide a method for powering an EV that includes receiving, at a power distribution module of the EV, power from a charger; during a charging mode, distributing, from the power distribution module, power received from the charger to a battery of the EV; during a discharging mode, drawing, by the power distribution module, power from the battery and distributing the power from the battery to a plurality of subsystems of the EV; and during a charging bypass mode, drawing, by the power distribution module, power from the charger and distributing the power from the charger to the plurality of subsystems of the EV, wherein the power from the charger bypasses the battery during the charging bypass mode. 
     Further embodiments of the present disclosure provide a fleet management system that includes a vehicle manager and a charging manager. The vehicle manager is configured to receive service requests from users and assign the service requests to EVs in a fleet of EVs. The charging manager is configured to identify, based on data from the vehicle manager, an idle EV of the fleet of EVs, the idle EV not currently assigned by the vehicle manager to a service request. The charging manager is further configured to instruct the idle EV to engage a charging bypass mode while connected to a charging station, the charging bypass mode causing power received from the charging station to bypass a battery of the idle EV and to be distributed to at least a subset of a plurality of subsystems of the idle EV. 
     As will be appreciated by one skilled in the art, aspects of the present disclosure, in particular aspects of powering an EV in a charging bypass mode, described herein, may be embodied in various manners (e.g., as a method, a system, a computer program product, or a computer-readable storage medium). Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Functions described in this disclosure may be implemented as an algorithm executed by one or more hardware processing units, e.g. one or more microprocessors, of one or more computers. In various embodiments, different steps and portions of the steps of each of the methods described herein may be performed by different processing units. Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer-readable medium(s), preferably non-transitory, having computer-readable program code embodied, e.g., stored, thereon. In various embodiments, such a computer program may, for example, be downloaded (updated) to the existing devices and systems (e.g. to the existing perception system devices and/or their controllers, etc.) or be stored upon manufacturing of these devices and systems. 
     The following detailed description presents various descriptions of specific certain embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims and/or select examples. In the following description, reference is made to the drawings where like reference numerals can indicate identical or functionally similar elements. It will be understood that elements illustrated in the drawings are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings. 
     The following disclosure describes various illustrative embodiments and examples for implementing the features and functionality of the present disclosure. While particular components, arrangements, and/or features are described below in connection with various example embodiments, these are merely examples used to simplify the present disclosure and are not intended to be limiting. It will of course be appreciated that in the development of any actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, including compliance with system, business, and/or legal constraints, which may vary from one implementation to another. Moreover, it will be appreciated that, while such a development effort might be complex and time-consuming; it would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     In the Specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present disclosure, the devices, components, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above”, “below”, “upper”, “lower”, “top”, “bottom”, or other similar terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components, should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the components described herein may be oriented in any desired direction. When used to describe a range of dimensions or other characteristics (e.g., time, pressure, temperature, length, width, etc.) of an element, operations, and/or conditions, the phrase “between X and Y” represents a range that includes X and Y. 
     Other features and advantages of the disclosure will be apparent from the following description and the claims. 
     Example System for Dispatch-Based Charging 
       FIG.  1    is a block diagram illustrating a system  100  including an example EV in a fleet of EVs in which powering the EV in a charging bypass mode according to some embodiments of the present disclosure may be implemented. The system  100  includes a fleet of electric vehicles (EVs)  110 , including EV  110   a , EV  110   b , and EV  110 N, a fleet management system  120 , and a charging station  130 . For example, a fleet of EVs may include a number N of EVs, e.g., EV  110   a  through EV  110 N. Some or all of the EVs  110  may be autonomous vehicles (AVs). EV  110   a  includes a sensor suite  140 , a battery  150 , and a power system  160 . EVs  110   b  through  110 N also include the sensor suite  140 , battery  150 , and power system  160 . A single EV in the fleet is referred to herein as EV  110 , and the fleet of EVs is referred to collectively as EVs  110 . The fleet management system  120  receives service requests for the EVs  110  and dispatches the EVs  110  to carry out the service requests. During a period when an EV, e.g., EV  110   a , has a fully charged battery  150  and is not dispatched by the fleet management system  120  to carry out a service request, the power system  160  may engage a charging bypass mode. During the charging bypass mode, the charging station  130  delivers power to the EV  110 , but the power bypasses the battery  150 . 
     In some embodiments, each EV  110  is a fully autonomous electric automobile. In other embodiments, each EV  110  may additionally or alternatively be another semi-autonomous or fully autonomous vehicle; e.g., a boat, an unmanned aerial vehicle, a driverless car, etc. Additionally, or alternatively, the EV  110  may be a vehicle that switches between a semi-autonomous state and a fully autonomous state and thus, the EV may have attributes of both a semi-autonomous vehicle and a fully autonomous vehicle depending on the state of the vehicle. In some embodiments, some or all of the EVs  110  are non-autonomous electric vehicles. 
     In embodiments where the EVs  110  are autonomous, each EV  110  may include a throttle interface that controls an engine throttle, motor speed (e.g., rotational speed of electric motor), or any other movement-enabling mechanism; a brake interface that controls brakes of the EV (or any other movement-retarding mechanism); and a steering interface that controls steering of the EV (e.g., by changing the angle of wheels of the EV). The EV  110  may additionally or alternatively include interfaces for control of any other vehicle functions; e.g., windshield wipers, headlights, turn indicators, air conditioning, etc. 
     The EV  110  includes a sensor suite  140 , which includes a computer vision (“CV”) system, localization sensors, and driving sensors. For example, the sensor suite  140  may include photodetectors, cameras, radar, sonar, lidar, GPS, wheel speed sensors, inertial measurement units (IMUS), accelerometers, microphones, strain gauges, pressure monitors, barometers, thermometers, altimeters, ambient light sensors, etc. The sensors may be located in various positions in and around the EV  110 . 
     An onboard computer (not shown in  FIG.  1   ) is connected to the sensor suite  140  and functions to control the EV  110  and to process sensed data from the sensor suite  140  and/or other sensors in order to determine the state of the EV  110 . Based upon the vehicle state and programmed instructions, the onboard computer modifies or controls behavior of the EV  110 . The onboard computer is preferably a general-purpose computer adapted for I/O communication with vehicle control systems and sensor suite  140 , but may additionally or alternatively be any suitable computing device. The onboard computer is preferably connected to the Internet via a wireless connection (e.g., via a cellular data connection). Additionally or alternatively, the onboard computer may be coupled to any number of wireless or wired communication systems. 
     The battery  150  is a rechargeable high voltage battery that powers the EV  110 . The battery  150  may be a lithium-ion battery, a lithium polymer battery, a lead-acid battery, a nickel-metal hydride battery, a sodium nickel chloride (“zebra”) battery, a lithium-titanate battery, or another type of rechargeable battery. In some embodiments, the EV  110  is a hybrid electric vehicle that also includes an internal combustion engine for powering the EV  110 , e.g., when the battery  150  has low charge. 
     The power system  160  controls the power and operation of the battery  150 , as well as the distribution of power within the EV. The power system  160  switches between various power modes, including (1) a charging mode, in which the battery  150  is charged from the charging station  130 , which may also power one or more subsystems of the EV  110 , (2) a discharging mode, in which the battery  150  is discharged and power drawn from the battery  150  powers one or more subsystems of the EV  110 , and (3) a charging bypass mode, in which one or more subsystems of the EV  110  receive power from a charging station  130 , and power drawn from the charging station  130  bypasses the battery  150 . The power system  160  may include or interface with battery sensors for determining a current charge level of the battery  150 . The power system  160  interfaces with the charging station  130  to initiate charging, request a specific charging rate, and end a charging session. The power system  160  may coordinate power distribution to various subsystems; for example, during charging, the power system  160  distributes power to one subset of subsystems (e.g., a communication subsystem and an autonomous driving sensor subsystem) and does not provide power to a different set of subsystems (e.g., a propulsion subsystem); during operation of the EV  110 , the power system  160  distributes power to a different subset of subsystems (e.g., a subset that includes the propulsion subsystem), or all to subsystems of the EV  110 . The power system  160  is described further in relation to  FIG.  2   . 
     The fleet management system  120  manages the fleet of EVs  110 . The fleet management system  120  may manage a service that provides or uses the EVs  110 , e.g., a service for providing rides to users with the EVs  110 , or a service that delivers items, such as prepared foods, groceries, or packages, using the EVs  110 . The fleet management system  120  may select an EV from the fleet of EVs  110  to perform a particular service or other task, and instruct the selected EV (e.g., EV  110   a ) to autonomously drive to a particular location (e.g., a delivery address). The fleet management system  120  also manages fleet maintenance tasks, such as charging and servicing of the EVs  110 . As shown in  FIG.  1   , each of the EVs  110  communicates with the fleet management system  120 . The EVs  110  and fleet management system  120  may connect over a public network, such as the Internet. The fleet management system  120  is described further in relation to  FIG.  2   . 
     The charging station  130  charges batteries of EVs  110 . The charging station  130  shown in  FIG.  1    has a cord and a plug; the plug is plugged into a socket of the EV  110   a . In other embodiments, the charging station  130  is a wireless charger, e.g., an inductive charger, or another type of charger. The charging station  130  may provide an alternating current (AC), such as an AC level 2 charger, or the charging station  130  may provide a direct current (DC), which may deliver charge at a faster rate. The charging station  130  may be configured to charge multiple EVs  110  simultaneously. The charging station  130  may communicate with the EV  110   a  through a wired connection (e.g., through the cord and plug shown in  FIG.  1   ) or through a wireless connection (e.g., Bluetooth or WiFi). The charging station  130  may also communicate with the fleet management system  120 , e.g., over the Internet. 
     The fleet management system  120  may operate a network of charging stations  130 . The network of charging stations may include a single type of charging stations (e.g., DC fast-charging stations), or a mix of charging stations (e.g., some AC level 2 charging stations, and some DC charging stations). Charging stations in the network may be distributed across one or more geographic regions in which the fleet of EVs  110  provides service. Charging stations may be included in EV facilities operated by the fleet management system  120 , e.g., facilities for storing, charging, and/or maintaining EVs. In some embodiments, the EVs  110  may use charging stations outside of the network operated by the fleet management system  120 , e.g., charging stations available to the public, charging stations in private homes, charging stations on corporate campuses, etc. 
     Example Power System 
       FIG.  2    is a block diagram illustrating a power system for powering various vehicle subsystems according to some embodiments of the present disclosure. The block diagram includes the battery  150 , the power system  160 , and various EV subsystems  230   a  through  230 N. The power system  160  includes an on-board charger  210 , a power distribution module  220 , a battery bypass module  240 , and a power system controller  250 . In alternative configurations, different and/or additional components may be included in the power system  160 . Further, functionality attributed to one component of the power system  160  may be accomplished by a different component included in the power system  160  or a different system than those illustrated. 
     The on-board charger  210  connects to a charging station  130  and converts alternating current (AC) output by the charging station  130  to direct current (DC) for storage in the battery  150  and for powering the subsystems  230 . The on-board charger  210  is used when the EV  110  is being charged by a charging station  130  that delivers AC. If the charging station  130  delivers DC, the on-board charger  210  is bypassed, and power is delivered directly from the charging station  130  to the power distribution module  220 . 
     The power distribution module  220  receives and distributes power to various components of the EV  110 . During charging, the power distribution module  220  receives power from the charging station  130 , either via the on-board charger  210  or directly from the charging station  130 . During operation of the EV  110 , when the battery  150  powers the EV  110  in a discharging mode, the power distribution module  220  draws power from the battery  150 . The power distribution module  220  distributes power from the charging station  130  to the battery  150  during charging. The power distribution module  220  distributes power to the subsystems  230   a - 230 N. 
     Subsystems  230   a - 230 N represent various subsystems of the EV  110  that are powered by the battery  150  or the charging station  130 , depending on the current power mode of the EV  110 . For example, subsystem 1  230   a  may be a vehicle propulsion system that draws power only when the EV  110  is in service (i.e., during the discharging mode), and subsystem 2  230   b  may be a communications system that draws power whether the EV  110  is idle or in service (i.e., during the charging mode, discharging mode, and charging bypass mode). Other subsystems include, for example, steering, braking, AV systems (such as the sensor suite  140  and signal processing systems), lighting, user interfaces, HVAC, etc. A single EV subsystem is referred to herein as subsystem  230 , and the collection of subsystems are referred to collectively as subsystems  230 . 
     The battery bypass module  240  is coupled to the battery  150  and power distribution module  220  and places the battery  150  in a charging bypass mode. The battery bypass module  240  may be a modified battery disconnect unit with additional switching capabilities, allowing the battery disconnect unit to be selectively engaged and disengaged. During charging and discharging modes, the battery bypass module  240  is not engaged, allowing power to flow between the battery  150  and the power distribution module  220 . During the charging bypass mode, the battery bypass module  240  is engaged, which disconnects the battery  150  from the power distribution module  220 . During charging bypass mode, the power distribution module  220  receives power from the charging station  130  and distributes the power to one or more of the subsystems  230  while bypassing the battery  150 . In some embodiments, the battery bypass module  240  comprises an additional switch (not shown) for connecting the on-board charger  210  when in use and disconnecting the on-board charger  210  when not in use. In some embodiments, the battery bypass module  240  comprises an additional switch (not shown) for connecting the power distribution module  220  to a plug for the external DC charger and disconnecting the plug when the external DC charger is not in use. 
     The power system controller  250  controls the other components of the power system  160 . The power system controller  250  interfaces with the battery bypass module  240  to engage and disengage the charging bypass mode. The power system controller  250  may connect to the battery  150  and interface with battery sensors to determine a current charge level of the battery  150 . The power system controller  250  interfaces with the power distribution module  220  to instruct the power distribution module  220  to distribute power to particular subsystems  230 , or to instruct the power distribution module  220  to not distribute power to particular subsystems  230 . 
     The power system controller  250  may identify subsystems  230  to power or not to power based on the power mode, e.g., powering some systems during the discharging mode but not during the charging mode or charging bypass mode. For example, the power system controller  250  selects at least one subsystem (e.g., a communications subsystem) to enable during the charging bypass mode, and transmits instructions to the power distribution module  220  to distribute power to the selected subsystem. The power system controller  250  may also select at least a second subsystem (e.g., a propulsion subsystem) to disable during the charging bypass mode, and transmit instructions to the power distribution module  220  not to distribute power to the second subsystem. The power system controller  250  may determine whether or not to power a subsystem based on the power mode and/or other rules. For example, during nighttime, the power system controller  250  instructs the power distribution module  220  to power the lighting subsystem, but during daytime, the lighting subsystem is powered off. 
     In some embodiments, the power system controller  250  receives instructions from the fleet management system  120  to engage or disengage the charging bypass mode of the battery bypass module  240 , and the power system controller  250  engages or disengages the charging bypass mode responsive to the instructions. In some embodiments, the power system controller  250  determines when to engage or disengage the charging bypass mode. For example, the EV  110  is connected to a charging station  130  and is drawing power from it. The power system controller  250  determines that the battery  150  has reached a full charge level, e.g., by receiving a signal from the battery  150  indicating that the battery  150  has a full charge. In response to the battery  150  reaching the full charge level, the power system controller  250  engages the charging bypass mode of the battery bypass module  240 . In response to the EV  110  disconnecting from the charging station  130 , e.g., when the EV  110  is assigned to a task, the power system controller  250  disengages the charging bypass mode of the battery bypass module  240 . 
     In some embodiments, the EV  110  includes multiple batteries  150 , e.g., a first battery used to power vehicle propulsion and maneuvering systems, and a second battery used to power AV hardware (e.g., the sensor suite  140  and the onboard computer). In such embodiments, the power system controller  250  manages charging of the multiple batteries. For example, the power system controller  250  instructs the power distribution module  220  to distribute power received from the on-board charger  210  or an external DC charger between the multiple batteries. The power system controller  250  also managers discharging of the multiple batteries, such as by instructing the power distribution module  220  to draw power from a particular battery or batteries and distribute the power to different subsystems. In some embodiments, each battery is associated with a respective power distribution module for distributing power from the battery to a respective subset of subsystems. The power system controller  250  may instruct the battery bypass module  240  to engage a charging bypass mode for each battery individually. For example, if the EV  110  is drawing power from a charging station, and one battery reaches full charge before a second battery, the power system controller  250  engages a charging bypass mode for the first battery and not the second battery. In some embodiments, each battery is coupled to a respective battery bypass module  240  configured to engage or disengage the charging bypass mode for its coupled battery, and the power system controller  250  engages the charging bypass mode for each battery bypass module  240  individually. 
     Example Fleet Management System 
       FIG.  3    is a block diagram illustrating the fleet management system  120  according to some embodiments of the present disclosure. The fleet management system  120  includes a UI (user interface) server  310 , a vehicle manager  320 , a demand prediction system  330 , and a charging manager  340 . In alternative configurations, different and/or additional components may be included in the fleet management system  120 . Further, functionality attributed to one component of the fleet management system  120  may be accomplished by a different component included in the fleet management system  120  or a different system than those illustrated. 
     The UI server  310  is configured to communicate with client devices that provide a user interface to users. For example, the UI server  310  may be a web server that provides a browser-based application to client devices, or the UI server  310  may be a mobile app server that interfaces with a mobile app installed on client devices. The user interface enables the user to access a service of the fleet management system  120 , e.g., to request a ride from an EV  110 , or to request a delivery from an EV  110 . 
     The vehicle manager  320  manages and communicates with a fleet of EVs, including EVs  110   a  through  110 N. The UI server  310  transmits service requests received from users to the vehicle manager  320 , and the vehicle manager  320  assigns EVs  110  to the service requests. More broadly, the vehicle manager  320  directs the movements of the EVs  110  in the fleet. The vehicle manager  320  may instruct EVs  110  to drive to other locations while not servicing a user, e.g., to improve geographic distribution of the fleet, to anticipate demand at particular locations, to drive to a charging station  130  for charging, etc. The vehicle manager  320  also instructs EVs  110  to return to EV facilities for recharging, maintenance, or storage. The vehicle manager  320  may receive data describing the current battery levels of the EVs  110  in the fleet, and based on the battery levels and current or predicted user demands, determine when EVs  110  in the fleet should be recharged. 
     In an embodiment, the UI server  310  receives a service request from a user, such as a request for a ride. The vehicle manager  320  identifies two eligible EVs that are charged and available to carry out assignments. The vehicle manager  320  assigns the request to one of the EVs. The vehicle manager  320  may inform the charging manager  340  that the other EV, which has not been assigned to carry out an assignment, is idle; based on this information, the charging manager  340  may instruct the idle EV to enter a charging bypass mode, while it awaits an assignment. If the UI server  310  receives another service request, e.g., a request for food delivery, that can be carried out by the idle EV, the vehicle manager  320  may assign the request to the idle EV, which disengages the charging bypass mode and services the request. 
     In some embodiments, the fleet management system  120  includes a demand prediction system  330  that predicts a demand for the fleet of EVs  110 . The demand prediction system  330  retrieves historical data describing previous demands on the fleet of EVs  110 , e.g., data describing numbers of assignments, durations of assignments, locations of assignments, and timing of assignments (day of week, time of day). The demand prediction system  330  uses this historical data to predict the demand for the fleet of EVs. In one example, the demand prediction system  330  predicts the demand levels for a period of time in the future, e.g., predicted demand over the next 5 hours, or predicted demand over the next 24 hours. In some embodiments, the demand prediction system  330  predicts an overall demand level or curve for the whole fleet, e.g., if the fleet is dedicated to one task (e.g., food delivery) and a particular region. In other embodiments, the demand prediction system  330  determines different demand levels or curves for various segments of the fleet, e.g., for a particular type of EVs (e.g., trucks, sedans, or luxury cars), for EVs within a particular geographic region, for EVs assigned to a particular function (e.g., EVs assigned to hot food delivery, EVs assigned to package delivery, or EVs assigned to giving rides to users), or a combination of factors (e.g., luxury cars used for a ride-sharing service within Austin, Tex.). 
     The vehicle manager  320  may use demand predictions from the demand prediction system  330  to assign EVs in the fleet to received assignments. For example, the vehicle manager  320  may instruct EVs to complete assignments, or to relocate in anticipation of predicted assignments, such that geographic distribution of the fleet can meet a predicted upcoming demand. The charging manager  340  may use demand predictions from the demand prediction system  330  to make charging decisions for the fleet of EVs, e.g., whether to maximize the number of EVs with a full charge due to a predicted high demand, or to allow some EVs in the fleet to be stored with emptier batteries while other EVs are placed in charging bypass mode to reduce strain and degradation of the batteries across the fleet. 
     The charging manager  340  manages charging of the EVs  110 . The charging manager  340  may instruct an EV  110  to apply a particular power mode, e.g., charging mode, discharging mode, or charging bypass mode. The charging manager  340  may coordinate charging across the fleet of EVs  110 . For example, the charging manager  340  monitors use of and demand on a set of charging stations  130  and instructs EVs  110  whether to charge based on the charging station demand. The charging manager  340  may also analyze various costs associated with different power modes and select a power mode for an EV  110  based on the costs. The charging manager  340  is described further in relation to  FIG.  4   . 
     Example Charging Manager 
       FIG.  4    is a block diagram illustrating the charging manager  340  according to some embodiments of the present disclosure. The charging manager  340  includes a power system analyzer  410 , a charging station manager  420 , an electricity rate planner  430 , and a power mode selector  440 . In alternative configurations, different and/or additional components may be included in the charging manager  340 . Further, functionality attributed to one component of the charging manager  340  may be accomplished by a different component included in the charging manager  340  or a different system than those illustrated. While the charging manager  340  is shown as a subsystem of the fleet management system  120 , in other embodiments, some or all of the components of the charging manager  340  are integrated into other systems, such as the charging station  130  or the EV  110 . For example, the charging station manager  420 , or some aspects of the charging station manager  420 , may be implemented by the charging station  130 . As another example, the power system analyzer  410  and/or the power mode selector  440  may be implemented by the EV  110 . 
     The power system analyzer  410  retrieves and processes data related to the battery  150  and power system  160 . The power system analyzer  410  may store data describing power use of the various subsystems  230 , including historical power usage and conditions that impact the power usage, such as weather conditions, ambient light, driving style, roadway conditions (e.g., speed, roadway type, terrain), frequency of stops, etc. The power system analyzer  410  can predict the power draws on the battery  150  or charging station  130  under specified conditions. In particular, the power system analyzer  410  can receive data identifying a set of subsystems  230  to power, and calculate an estimated power draw rate for powering the set of subsystems  230  based on the data describing the current conditions and data describing the historical power usage of the set of subsystems  230 . In some embodiments, the power system analyzer  410  may calculate the estimated power draw rate based on historical subsystem power draw data collected across multiple EVs in the fleet. 
     The power system analyzer  410  may also store data describing previous charge events and discharge events of the battery  150  and/or a set of batteries  150  the fleet of EVs  110 . For example, the data describing charge events includes charge levels, changes in the charge level, and charging rate supplied by a power source (e.g., a charging station  130 , regenerative braking, or other sources). The data describing discharge events may include charge levels, changes in charge levels, and power draws on the battery  150  from various subsystems  230 . The power system analyzer  410  can also predict the response of the battery  150  to planned charge and discharge events based on the historical battery data for the battery  150  and/or battery data for multiple batteries across the fleet of EVs  110 . 
     In some embodiments, the power system analyzer  410  also uses the historical charging data to determine the length of time for the battery  150  to reach a target charge level (e.g., a full charge level) from the current charge level when charging at a charging station  130 . The power system analyzer  410  may account for a power draw from subsystems  230  that remain on during charging when calculating the length of time to reach the target charge level. The power system analyzer  410  may continually update the length of time to reach the target charge level during charging in response to updated data about the power draws, target charge level, and current charge level. The power system analyzer  410  may provide the time to reach the target charge level to the vehicle manager  320 , which determines when the EV  110  is predicted to be available for service. 
     The power system analyzer  410  may also assess and predict degradation of the battery  150  based on the historical battery data and fleet-wide battery information. In an example, the power system analyzer  410  retrieves data describing degradation costs on the battery  150  due to charging and discharging events. The data may include, for example, degradation costs of charging the battery  150  at different charging rates; degradation costs of storing the battery  150  at different charge levels; and degradation costs of powering the EV  110  or a set of subsystems  230  with the battery  150 , which may include the cost of recharging the battery  150  to compensate for the power provided. In general, discharging and recharging a battery degrades the battery, and storing a battery with a higher charge degrades the battery more than storing a battery at a lower charge. The power system analyzer  410  may calculate the degradation costs for a particular battery  150  based on the age of the battery, current state of the battery (e.g., full charge level that the battery can currently receive vs. full charge level when new; current time to reach full charge from empty vs. time to reach full charge when new), environmental conditions, or other factors in combination with historical battery data. 
     The charging station manager  420  retrieves and processes data related to the charging stations  130 . The charging station manager  420  may maintain data describing the type and charging rate for each charging station  130  that charges the fleet of EVs  110 . The charging station manager  420  may maintain data describing demand for the charging stations  130  by the EVs  110  in the fleet. For example, the charging station manager  420  maintains a charging queue for each charging station  130 , where the charging queue lists EVs  110  waiting to use the charging station  130  and/or en route to the charging station  130 . As another example, the charging station manager  420  receives data describing projected demands on the charging stations  130  from the vehicle manager  320 , which determines when EVs  110  in the fleet should be recharged based on current battery levels across the fleet and current and/or projected service demands. The charging station manager  420  may select a particular charging station  130  at which an EV  110  recharges based on the location of the EV  110  relative to the charging station  130 , whether there is an EV currently charging at the charging station  130  and the expected remaining charge duration of the currently charging EV, a queue of EVs waiting to charge at the charging station  130 , the maximum charging rate provided by the charging station  130 , or other factors. 
     The electricity rate planner  430  determines energy costs for drawing power from a charging station  130 . In some embodiments, the electricity rate planner  430  retrieves data describing current and future energy costs (e.g., energy costs for the next 24 hours) from an electricity company or another source. In some embodiments, the electricity rate planner  430  determines anticipated energy costs over a period of time (e.g., the next 12 hours) based on the current energy cost and historical data stored by the electricity rate planner  430  or retrieved from another source. The electricity rate planner  430  may determine different anticipated energy costs for multiple different charging stations  130 , e.g., charging stations that receive power from different energy companies may have different rates, and a charging station that is fully or partially solar powered may have a lower rate or no fee. 
     The power mode selector  440  selects a power mode for powering an EV  110 , e.g., discharging mode, charging mode, or charging bypass mode. The power mode selector  440  selects a power mode based on data from the power system analyzer  410 , charging station manager  420 , and/or electricity rate planner  430 . In some embodiments, the power mode selector  440  selects a power mode based on fleet-wide considerations, such as demand for services provided by the fleet, demand for charging stations by the fleet, operating costs, and/or degradation costs. The power mode selector  440  may transmit instructions to the power system controller  250  to implement a power mode. In some embodiments, either the power system controller  250  or the power mode selector  440  selects the power mode for the EV  110 . In other embodiments, the power mode selector  440  is incorporated into the power system controller  250 , and the power mode selector  440  receives data from the fleet management system  120  that the power mode selector  440  may use to determine the power mode. In still other embodiments, the power system controller  250  selects a power mode for the EV  110 , and the power mode selector  440  may override the power mode selected by the power system controller  250 . 
     In an embodiment, the power mode selector  440  retrieves charging station data from the charging station manager  420 . For example, when an EV  110  is charging at a charging station  130 , the charging station manager  420  identifies the charging station  130  that is charging the EV  110 , retrieves data describing the demand for the charging station  130  (e.g., predicted demand or a current charging queue), and provides this charging station demand data to the power mode selector  440 . If the power mode selector  440  determines that the charging station  130  is available to the EV  110  after the battery  150  has reached a full charge, the power mode selector  440  instructs the EV  110  to engage the charging bypass mode. Alternatively, if the power mode selector  440  determines that the charging station  130  is not available, e.g., another EV is waiting to charge, the power mode selector  440  instructs the EV  110  to enter the discharging mode and disconnect from the charging station  130 . 
     In an embodiment, the power mode selector  440  determines whether to engage the charging bypass mode by comparing the cost of drawing power from the charging station  130  to the costs associated with powering the EV  110  from the battery  150 . In particular, the power mode selector  440  determines a cost of powering a subset of subsystems  230 , e.g., subsystems  230  that continue operating while the EV  110  is not in service, by the charging station  130 , and determines the cost of powering this subset of subsystems  230  from the battery. If the cost of powering the subset of subsystems by the charging station  130  is lower than the cost of powering the subset of subsystems from the battery  150 , the power mode selector  440  instructs the EV  110  to engage the charging bypass mode. 
     To determine the cost of powering the subset of subsystems  230  from the charging station  130 , the power mode selector  440  may retrieve an estimated power draw rate for the subset of subsystems  230  from the power system analyzer  410 , and retrieve current electricity rates for the charging station  130  from the electricity rate planner  430 . The power mode selector  440  calculates the cost of powering the subset of subsystems  230  based on the current electricity rates and the estimated power draw, i.e., by multiplying the power draw by the electricity rate to determine a cost rate for utilizing the charging station  130  in charging bypass mode. 
     To determine the cost of powering the subset of subsystems  230  from the battery  150 , the power mode selector  440  retrieves the degradation cost to the battery  150  associated with powering the subset of subsystems  230  from the power system analyzer  410 . The degradation cost may be a cost rate, e.g., the battery  150  degrades by $0.10 for each hour the battery  150  is used to power a given subset of subsystems  230 . The power mode selector  440  retrieves an estimated electricity rate for recharging the battery  150  (e.g., from the charging station  130  or from a different charging station) from the electricity rate planner  430 . For example, the power mode selector  440  may retrieve the lowest expected electricity rate over the next 12 hours, to minimize recharging costs. The power mode selector  440  determines the cost of powering the subset of subsystems  230  from the battery  150  based on the degradation cost and the estimated cost of recharging the battery, e.g., by adding the degradation cost rate to the estimated electricity rate to calculate an overall cost rate of using battery power. 
     Example Processes for Selecting and Applying a Power Mode 
       FIG.  5    is a flowchart showing a process for selecting and applying power modes of the EV according to some embodiments of the present disclosure. An EV, such as EV  110 , connects  510  to a charging station, such as charging station  130 . The EV  110  may connect, or be connected to, to the charging station  130 , e.g., with the cord and plug shown in  FIG.  1   , through a wireless communications connection, and/or through a wireless charging connection. In some embodiments, the EV  110  can connect to the charging station  130  to receive power autonomously, e.g., without a manual connection. In other embodiments, the EV  110  is manually plugged into the charging station  130 . In response to the EV  110  connecting to the charging station  130 , the EV  110  and/or the charging station  130  transmits a signal to the fleet management system  120  indicating that the EV  110  has connected to the charging station  130 . 
     The charging station  130  charges  520  the EV battery  150  in a charging mode. In the charging mode, the power distribution module  220  receives power from either the on-board charger  210  or directly from the charging station  130 . The power distribution module  220  distributes power to a subset of the subsystems  230 , e.g., a set of subsystems  230  that continue to operate while the EV  110  is idle. The power distribution module  220  also distributes power to the battery  150 . The battery bypass module  240  is not engaged. 
     The power system controller  250  determines  530  if the battery  150  is fully charged. If the battery  150  is not fully charged, the power system controller  250  keeps the power system  160  in the charging mode. If the battery  150  is fully charged, the power system controller  250  checks  540  if the EV  110  has been dispatched by the fleet management system  120 . For example, the EV  110  may have been assigned a service request. Or, the EV  110  may have been instructed to disconnect from the charging station  130  so that another EV can be charged. 
     If the EV  110  has been dispatched, the EV  110  disconnects  560  from the charging station  130 , and the power system controller  250  implements the discharging mode. In the discharging mode, the power distribution module  220  draws power from the battery  150  and distributes the power to a subset of the subsystems  230  (e.g., if the EV  110  is idle and awaiting a service assignment), or all of the subsystems  230  (e.g., if the EV  110  is driving). 
     If the EV  110  has not been dispatched, the power system controller  250  engages  550  battery bypass module  240  in the charging bypass mode. In the charging bypass mode, the power distribution module  220  receives power from either the on-board charger  210  or directly from the charging station  130 , and the power distribution module  220  distributes power to a subset of the subsystems  230 , e.g., the set of subsystems  230  that continue to operate while the EV  110  is idle. Power bypasses the battery  150 . During the charging bypass mode, the power system controller  250  continues to check if the EV  110  has been dispatched. In response to the EV being dispatched, the power system controller disengages the battery bypass module  240  and enters the discharging mode. 
     Select Examples 
     Example 1 provides a system for powering an electric vehicle (EV) that includes a battery, a power distribution module, and a battery bypass module. The power distribution module is configured to receive power from a charging station, draw power from the battery in a discharging mode, distribute power from the charging station to the battery in a charging mode, and distribute power to a plurality of subsystems of the EV. The battery bypass module is coupled to the battery and to the power distribution module. The battery bypass module, when engaged in a charging bypass mode, causes power distributed by the power distribution module to bypass the battery and to be distributed to at least a subset of the plurality of subsystems of the EV. 
     Example 2 provides the system according to example 1, further including a power system controller configured to determine that the battery has reached a full charge level, engage the charging bypass mode of the battery bypass module in response to the battery reaching the full charge level, and disengage the charging bypass mode of the battery bypass module in response to the EV disconnecting from the charging station. 
     Example 3 provides the system according to example 1 or 2, further including a power system controller configured to select at least one subsystem of the EV to enable during the charging bypass mode, and transmit instructions to the power distribution module to distribute power to the at least one subsystem of the EV while the charging bypass mode is engaged. 
     Example 4 provides the system according to example 3, where the power system controller is further configured to select at least a second subsystem of the EV to disable during the charging bypass mode, and transmit instructions to the power distribution module to not distribute power to the second subsystem of the EV while the charging bypass mode is engaged. 
     Example 5 provides the system according to any of the preceding examples, further including a charging manager configured to identify the charging station from which the EV is receiving power, retrieve data describing demand for the charging station by a fleet of EVs, the fleet comprising the EV, and in response to determining that the charging station is available to the EV after the battery has reached a full charge, instruct the EV to engage the charging bypass mode. 
     Example 6 provides the system according to any of the preceding examples, further including a fleet management system configured to receive a service request from a user; assign the service request to a second EV in a fleet of EVs, the fleet comprising the EV; instruct the EV to engage the charging bypass mode; receive a second service request from a second user; and assign the second service request to the EV, where the EV disengages the charging bypass mode in response to receiving the service request. 
     Example 7 provides the system according to any of the preceding examples, further including a charging manager configured to determine a cost of powering the subset of the plurality of subsystems by the charging station, determine a cost of powering the subset of the plurality of subsystems from the battery, and, in response to determining that the cost of powering the subset of the plurality of subsystems by the charging station is lower than the cost of powering the subset of the plurality of subsystems from the battery, transmit an instruction to engage the charging bypass mode. 
     Example 8 provides the method according to example 7, where determining the cost of powering the subset of the plurality of subsystems by the charging station includes calculating an estimated power draw rate for powering the subset of the plurality of subsystems of the EV, retrieving current electricity rates for the charging station, and calculating the cost of powering the subset of the plurality of subsystems based on the current electricity rates and the estimated power draw. 
     Example 9 provides the method according to example 7 or 8, where determining the cost of powering the subset of the plurality of subsystems from the battery includes calculating a degradation cost to the battery associated with powering the plurality of subsystems from the battery, calculating an estimated cost of recharging the battery, and determining the cost of powering the subset of the plurality of subsystems from the battery based on the degradation cost and the estimated cost of recharging the battery. 
     Example 10 provides the system according to any of the preceding examples, further including an on-board charger configured to convert alternating current (AC) received from the charging station to direct current (DC), wherein the power distribution module is configured to receive power from a DC charging station or from the charging station via the on-board charger. 
     Example 11 provides a method for powering an electric vehicle (EV) including receiving, at a power distribution module of the EV, power from a charging station; during a charging mode, distributing, from the power distribution module, power received from the charging station to a battery of the EV; during a discharging mode, drawing, by the power distribution module, power from the battery and distributing the power from the battery to a plurality of subsystems of the EV; and during a charging bypass mode, drawing, by the power distribution module, power from the charging station and distributing the power from the charging station to the plurality of subsystems of the EV, wherein the power distributed by the power distribution module bypasses the battery during the charging bypass mode. 
     Example 12 provides the method according to example 11, further including determining that the battery has reached a full charge level during the charging mode; in response to the battery reaching the full charge level, engaging the charging bypass mode of the battery bypass module; and disengaging the charging bypass mode of the battery bypass module in response to the EV disconnecting from the charging station. 
     Example 13 provides the method according to example 11 or 12, further including selecting at least one subsystem of the EV to enable during the charging bypass mode, selecting at least a second subsystem of the EV to disable during the charging bypass mode, and transmitting instructions to the power distribution module to distribute power to the at least one subsystem of the EV while the charging bypass mode is engaged. 
     Example 14 provides the method according to any of examples 11 through 13, further including retrieving data describing demand for charging stations by EVs in a fleet of EVs, the fleet comprising the EV; and in response to determining that the charging station is available to the EV after the battery has reached a full charge, instructing the EV to engage the charging bypass mode. 
     Example 15 provides the method according to any of examples 11 through 14, further including receiving a service request from a user; assigning the service request to a second EV in a fleet of EVs, the fleet comprising the EV; instructing the EV to engage the charging bypass mode; receiving a second service request from a second user; and assigning the second service request to the EV, where the EV disengages the charging bypass mode in response to receiving the service request. 
     Example 16 provides the method according to any of examples 11 through 15, further including determining a cost of powering the subset of the plurality of subsystems by the charging station; determining a cost of powering the subset of the plurality of subsystems from the battery; and in response to determining that the cost of powering the subset of the plurality of subsystems by the charging station is lower than the cost of powering the subset of the plurality of subsystems from the battery, transmitting an instruction to engage the charging bypass mode. 
     Example 17 provides the method according to example 16, where determining the cost of powering the subset of the plurality of subsystems by the charging station includes calculating an estimated power draw rate for powering the subset of the plurality of subsystems of the EV; retrieving current electricity rates for the charging station; and calculating the cost of powering the subset of the plurality of subsystems based on the current electricity rates and the estimated power draw. 
     Example 18 provides the method according to example 16 or 17, where determining the cost of powering the subset of the plurality of subsystems from the battery includes calculating a degradation cost to the battery associated with powering the plurality of subsystems from the battery; calculating an estimated cost of recharging the battery; and determining the cost of powering the subset of the plurality of subsystems from the battery based on the degradation cost and the estimated cost of recharging the battery. 
     Example 19 provides a fleet management system comprising a vehicle manager configured to receive service requests from users and assign the service requests to EVs in a fleet of EVs; and a charging manager configured to identify, based on data from the vehicle manager, an idle EV of the fleet of EVs, the idle EV not currently assigned by the vehicle manager to a service request; and instruct the idle EV to engage a charging bypass mode while connected to a charging station, the charging bypass mode causing power received from the charging station to bypass a battery of the idle EV and to be distributed to at least a subset of the plurality of subsystems of the idle EV. 
     Example 20 provides the fleet management system according to example 19, where the charging manager is further configured to instruct the idle EV to engage the charging bypass mode in response to determining that the battery of the EV is fully charged, and in response to the vehicle manager assigning a service request to the idle EV, instruct the idle EV to disengage the charging bypass mode. 
     OTHER IMPLEMENTATION NOTES, VARIATIONS, AND APPLICATIONS 
     It is to be understood that not necessarily all objects or advantages may be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that certain embodiments may be configured to operate in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. 
     In one example embodiment, any number of electrical circuits of the figures may be implemented on a board of an associated electronic device. The board can be a general circuit board that can hold various components of the internal electronic system of the electronic device and, further, provide connectors for other peripherals. More specifically, the board can provide the electrical connections by which the other components of the system can communicate electrically. Any suitable processors (inclusive of digital signal processors, microprocessors, supporting chipsets, etc.), computer-readable non-transitory memory elements, etc. can be suitably coupled to the board based on particular configuration needs, processing demands, computer designs, etc. Other components such as external storage, additional sensors, controllers for audio/video display, and peripheral devices may be attached to the board as plug-in cards, via cables, or integrated into the board itself. In various embodiments, the functionalities described herein may be implemented in emulation form as software or firmware running within one or more configurable (e.g., programmable) elements arranged in a structure that supports these functions. The software or firmware providing the emulation may be provided on non-transitory computer-readable storage medium comprising instructions to allow a processor to carry out those functionalities. 
     It is also imperative to note that all of the specifications, dimensions, and relationships outlined herein (e.g., the number of processors, logic operations, etc.) have only been offered for purposes of example and teaching only. Such information may be varied considerably without departing from the spirit of the present disclosure, or the scope of the appended claims. The specifications apply only to one non-limiting example and, accordingly, they should be construed as such. In the foregoing description, example embodiments have been described with reference to particular arrangements of components. Various modifications and changes may be made to such embodiments without departing from the scope of the appended claims. The description and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense. 
     Note that with the numerous examples provided herein, interaction may be described in terms of two, three, four, or more components. However, this has been done for purposes of clarity and example only. It should be appreciated that the system can be consolidated in any suitable manner. Along similar design alternatives, any of the illustrated components, modules, and elements of the FIGS. may be combined in various possible configurations, all of which are clearly within the broad scope of this Specification. 
     Note that in this Specification, references to various features (e.g., elements, structures, modules, components, steps, operations, characteristics, etc.) included in “one embodiment”, “example embodiment”, “an embodiment”, “another embodiment”, “some embodiments”, “various embodiments”, “other embodiments”, “alternative embodiment”, and the like are intended to mean that any such features are included in one or more embodiments of the present disclosure, but may or may not necessarily be combined in the same embodiments. 
     Numerous other changes, substitutions, variations, alterations, and modifications may be ascertained to one skilled in the art and it is intended that the present disclosure encompass all such changes, substitutions, variations, alterations, and modifications as falling within the scope of the appended claims. Note that all optional features of the systems and methods described above may also be implemented with respect to the methods or systems described herein and specifics in the examples may be used anywhere in one or more embodiments. 
     In order to assist the United States Patent and Trademark Office (USPTO) and, additionally, any readers of any patent issued on this application in interpreting the claims appended hereto, Applicant wishes to note that the Applicant: (a) does not intend any of the appended claims to invoke paragraph (f) of 35 U.S.C. Section 112 as it exists on the date of the filing hereof unless the words “means for” or “step for” are specifically used in the particular claims; and (b) does not intend, by any statement in the Specification, to limit this disclosure in any way that is not otherwise reflected in the appended claims.