Patent ID: 12237482

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Maintenance of automotive vehicles with internal combustion engines is a well-known art. Procedures are known for servicing the internal combustion engine of the vehicles, the drive train, the battery (which is generally used to start the vehicle and operate the electrical devices within the vehicle), and the fuel storage and distribution system. In contrast, widespread use of electrical vehicles is a relatively new phenomenon and there is an ongoing need for improved procedures for performing maintenance on the batteries of such vehicles. For example, when a traditional vehicle with an internal combustion engine is involved in an accident, it is typical to drain the gasoline or other fuel from the vehicle for safety purposes. In contrast, when an electrical vehicle is involved in an accident, the battery pack of the vehicle may contain a relatively large amount of energy, and may even be in a fully charged state. It is not at all apparent how the battery pack can be discharged as there are many different types of battery pack, as well as various techniques used to access the packs. Further, after an accident, systems of the vehicle may not be functioning properly and may prevent maintenance from being performed on the battery pack whereby the battery pack cannot be discharged using normal procedures. In one aspect, the present invention provides an apparatus and method for safely accessing the battery pack of an electrical vehicle and discharges the battery pack. However, the present invention is not limited to this configuration and may be used generally to perform maintenance on the battery pack of an electric vehicle.

The device of the present invention can be used to “de-power” the battery pack of an electric vehicle or provide other maintenance on the battery pack including charging the battery pack. In general, this activity can be problematic for a number of reasons. First, different types of electric vehicles use different types of battery packs. The configuration, voltages, and connection to such packs vary greatly. Further, the vehicle itself typically includes “intelligence” to control the charging and discharging, as well as monitoring the status of the battery pack. Further still, some battery packs themselves include “intelligence” to control the charging and discharging of the battery pack as well as monitor the status of the battery pack. The device of the present invention is capable of interfacing with a databus of the vehicle and/or a databus of the battery pack in order to control and monitor operation of the battery pack. Again, the connection to these databuses varies greatly between vehicles. Further still, the data format and specific data varies between vehicles. The problem of performing maintenance on a battery pack is exacerbated when a vehicle has been in an accident. The battery pack may be physically difficult to access and it may be difficult to obtain electrical connections to the battery pack and/or vehicle for discharging the battery as well as for communicating over the vehicle or battery pack databus. Depending on the damage which occurs during an accident, the battery pack may be isolated for safety reasons. This isolation presents another challenge in accessing the battery pack. Further, the circuitry of the maintenance device must be capable of operating with the relatively high DC voltages, for example 400 Volts, which are present in electrical vehicle battery packs. These high voltages must be isolated from the logic and control circuitry of the device as well as the operator. Additionally, in one aspect, the device also includes a charger function for use in charging some or all of the cells of a battery pack in order to place the battery pack into service.

Electric vehicles typically includes “contactors” which are electrically operated relays (switches) used to selectively couple the high voltage from the battery pack to the powerful electric motors used in the drive train of the vehicle. In order to access the battery pack from a location on the vehicle, it is necessary for these contactors to be closed to complete the electrical circuit. However, in an accident, the controlling electronics of the vehicle and/or battery pack will typically disconnect (open) the contactors for safety purposes in order to isolate the battery pack from the vehicle. Thus, in one embodiment, the present invention communicates with the controller of the electrical vehicle or battery pack, or directly with the contactors, to cause the contactors to close and thereby provide access to the high voltage of the battery pack. When communicating with the control system of the vehicle, the device of the present invention can provide information to the vehicle system indicating that it is appropriate for the contactors to close. Thus, failure indications or other errors, including errors associated with a vehicle being in an accident, must be suppressed. Instead, information is provided to the vehicle system by the battery pack maintenance device which indicates that it is appropriate for the contactors to be closed.

When servicing battery packs on electrified vehicles, including HEV, PHEV, and BEV, common operations are pack or module charge, pack or module discharge, and pack or module balance. During these operations, it is frequently desired to monitor the individual cell voltages and temperatures contained within the pack or module. Packs and modules generally consist of a plurality of series, parallel, or series/parallel connections of cells.

These cell voltages and temperatures can be obtained from on-module electronics, in which case a communication link is used to monitor the voltages.

However, more commonly, a connector is presented on the battery module which contains nodes which are tied to the individual cell connections. Electronics within the battery structure connects through cabling to monitor the cell voltages and temperatures for normal vehicle operation.

FIG.1is a simplified block diagram showing battery pack maintenance device100coupled to an electric vehicle102. The vehicle102is illustrated in a simple block diagram and includes a battery pack104used to power the vehicle102including providing power to motor(s)106of the vehicle. The vehicle102includes a vehicle controller108coupled to a databus110of the vehicle. The controller108receives information regarding operation of the vehicle through sensors112and controls operation of the vehicle through outputs114. Further, the battery pack104is illustrated as including its own optional controller120which monitors operation of the battery pack104using battery pack sensors122.

Many semiconductor manufacturers produce highly integrated silicon circuits designed to monitor the many cell voltages and temperatures present. These devices work well in the intended application, as they have very specific polarity and cell voltage limits, but the chassis wiring of the battery pack ensures that no improper connections can be made. When connecting battery maintenance equipment to the battery module, it is important that the correct connection is used. If connected incorrectly, the voltages present on the module can damage the maintenance equipment. This requires the operator to ensure that the correct connector/wiring harness is chosen. If the incorrect connector/wiring harness is chosen, incorrect measurements/charging can occur. In some cases the maintenance equipment can be damaged.

During operation, the electric vehicle102is controlled by the controller108, for example, based upon input from a driver through operator I/O109. Operator I/O109can comprise, for example, a foot accelerator input, a brake input, an input indicating an position of a steering wheel, information related to a desired gearing ratio for a drive train, outputs related to operation of the vehicle such as speed, charging information, amount of energy which remains in the battery pack104, diagnostic information, etc. The controller108can control operation of the electric motors106to propel the vehicle, as well as monitor and control other systems of the vehicle102. The controller120of battery pack104can be used to monitor the operation of the battery pack104. For example, the sensors122may include temperature sensors configured to disconnect the batteries of the battery pack if a threshold temperature is exceeded. Other example sensors include current or voltage sensors, which can be used to monitor charge of the battery pack104.FIG.1also illustrates contactor relays130of the vehicle102which are used to selectively decouple the battery pack104from systems of the vehicle102as discussed above. For example, the controller108can provide a signal to cause the contactors130to close thereby connecting the battery pack104to electrical systems of the vehicle102.

Battery pack maintenance device100includes a main unit150which couples to the vehicle through a low voltage junction box152and a high voltage junction box154. These junction boxes152,154are optional and other techniques may be used for coupling the maintenance device100to the vehicle102. Maintenance device100includes a microprocessor160, I/O circuitry162and memory164which contains, for example, programming instructions for use by microprocessor160. The I/O circuitry162can be used to both user input, output, remote input, output as well as input and output with vehicle102. The maintenance device100includes a controllable load170for use in discharging the battery pack104. An optional charging source171is also provided and can be used in situations in which it is desirable to charge the battery pack104, for example, to perform maintenance on the battery pack104. The high voltage junction box154is used to provide an electrical connection between terminals of the battery pack104and the maintenance device main unit150. Using this connection, batteries within the battery pack104can be discharged using the load170or charged using the charging source171. Similarly, low voltage junction box152is used by battery pack maintenance device100to couple to low voltage systems of the electric vehicle102. Such systems include the databus110of the vehicle, sensors112, outputs114, etc. Through this connection, as discussed above, the maintenance device100can gather information regarding the condition of systems within the vehicle102including the battery pack104, and can control operation of systems within the vehicle102. Similarly, through this connection, the outputs from sensors112can be changed or altered whereby altered sensor outputs can be provided to controller108. This can be used, for example, to cause controller108to receive information indicating that the vehicle102or battery pack104is in a condition which is different than from what the sensors112are actually sensing. For example, this connection can be used to cause the contactors130to close to thereby provide an electrical connection to the battery pack104. Further, the low voltage junction box152can be used to couple to the controller120and/or sensors122of the battery pack104. The junction boxes152,154couple to vehicle102through the use of an appropriate connector. The particular connector which is used can be selected based upon the specific type of vehicle102and the type of connections which are available to an operator. For example, OBD II connection can be used to couple to the databus110of the vehicle. Other plugs or adapters may be used to couple to sensors112or outputs114. A particularly style plug may be available for coupling the high voltage junction box154to the battery pack104. If there are no contactors which are available or if they cannot be accessed or are unresponsive, in one configuration clips or other types of clamp on or selectively connectable contactors can be used to perform the coupling.

FIG.2is a simplified block diagram of a battery pack maintenance device100in accordance with one example embodiment of the present invention. The device includes microprocessor160which operates in accordance with instructions stored in a memory164. A power supply is used to provide power to the device. The power supply180can be coupled to an AC power source, such as a wall outlet or other high power source, for use in charging the battery pack104of the vehicle102. Additionally, the power supply180can be coupled to a DC power source, such as a 12 Volt battery, if the device100is only used for discharging of the vehicle battery pack104. For example, in addition to the battery pack104, many electric vehicles also include a standard 12 Volt automotive battery. This 12 Volt automotive battery can be used to power maintenance device100. The microprocessor communicates with an operator using an operator input/output182. Other input/output circuitry184is provided for use in physically connecting to a data communication link such as an RS232, USB connection, Ethernet, etc. An optional wireless I/O circuit186is also provided for use in communicating in accordance with wireless technologies such as WiFi techniques, Bluetooth®, Zigbee®, etc. Low voltage input/output circuitry190is provided for use in communicating with the databus of the vehicle108, the databus of the battery pack104, or receiving other inputs or providing outputs to the vehicle102. Examples include the CAN communication protocol, OBDII, etc. Additionally, contact closures or other voltage inputs or outputs can be applied to the vehicle using the low voltage I/O circuitry190.FIG.2also illustrates an operator shut off switch192which can be activated to immediately disconnect the high voltage control170from the battery104using disconnect switch194. Other circuit configurations can be used to implement this shut off capability. This configuration allows an operator to perform an emergency shut off or otherwise immediately disconnect the device100from the battery if desired.

The low voltage junction box152also provides an optional power output. This power can be used, for example, to power components of the vehicle102if the vehicle102has lost power. This can be useful, for example, to provide power to the controller108of the vehicle102such that information may be gathered from the vehicle and various components of the vehicle can be controlled such as the contactors130.

In one configuration, the connection between the high voltage control circuitry170and the high voltage junction box154is through Kelvin type connectors. This can be used to eliminate the voltage drop which occurs when large currents are drawn through wiring thereby provide more accurate voltage measurements. The actual connection between the junction box154and the battery pack104need not be through a Kelvin connection if the distance between the junction box154and the battery pack104is sufficiently short for the voltage drop across the connection leads to be negligible. Isolation circuitry such as fuses may be provided in the junction box154to prevent the application of a high voltage or current to the maintenance device100and thereby protect circuitry in the device. Similarly, the low voltage junction box152and/or the low voltage I/O190may include isolation circuitry such as optical isolators, inductors to provide inductive coupling, or other techniques. The low voltage junction box152may also include an optional user output and/or input196. For example, this may be a display which can be observed by an operator. An example display includes an LED display, or individual LEDs, which provides an indication to the operator regarding the functioning of the low voltage junction box, the vehicle, or the battery pack. This can be used to visually inform an operator regarding the various functions being performed by the low voltage junction box, voltages detected by the low voltage junction box. A visual output and/or input198can be provided on the high voltage junction box154.

The appropriate high voltage junction box154and low voltage junction box152can be selected based upon the particular vehicle102or battery pack104being inspected. Similarly, the junction boxes152,154can be selected based upon the types of connections which are available in a particular situation. For example, if the vehicle his damaged, it may be impossible to couple to the battery pack104through available connectors. Instead, a junction box154can be employed which includes connection probes which can be coupled directly to the battery pack104. Further still, if such a connection is not available or is damaged, connectors can be provided for coupling to individual cells or batteries within the battery pack104.

The use of the low voltage and high voltage junction boxes152,154are advantageous for a number of reasons. The junction boxes can be used to provide a standardized connection to the circuitry of the maintenance device100. From a junction box152,154, specialized connectors can be provided for use with different types of vehicles and/or battery packs. Similarly, different types of junction boxes152,154can be utilized for different vehicles and/or battery packs. The junction boxes152,154allow a single set cable connection to extend between the device100and a remote location. This provides better cable management, case of use, and increased accuracy.

In addition to use as a load for discharging the battery, the high voltage control circuitry may also optionally include a charging for use in charging the battery.

FIG.3is a schematic diagram of controllable load170. InFIG.3, a number of isolated gate bipolar transistors (IGBT)220A,220B,220C, and220D are shown and controlled by a gate connection to microprocessor160. The IGBTs220A-D connect to load resistors222A,222B,224A, and224B. As illustrated inFIG.3, the four load resistors are 33 OHM resistors. Using the transistors220A-D, the resistors222A, B and224A, B can be coupled in various series-parallel configurations in order to apply different loads to the battery pack104. In this way, the load applied to the battery pack104is controllable by microprocessor160. In one aspect, the present invention includes isolated gate bipolar transistors (IGBT) to selectively couple loads to the battery pack104for discharging the pack. An IGBT is a transistor configured with four semiconducting layers arranged as PNPN. A metal oxide semiconductor is arranged to provide a gate. The configuration provides a transistor which is controlled easily in a manner similar to a field effect transistor but which is also capable of switching large currents like a bipolar transistor.

When the device100is coupled to a vehicle102which has been in an accident, the device can perform various tests on the vehicle102to determine the condition of the vehicle and the battery. For example, in one aspect, the device100detects a leakage between the positive and negative terminals of the battery pack102and the ground or chassis of the vehicle102. For example, a wheat stone bridge circuit230can be used between the positive and negative terminals of the battery pack104with one of the legs of the bridge connected to ground.

During discharging of the vehicle battery pack104, data can be collected from the battery pack. For example, battery packs typically include sensors122such as voltage, current and temperature sensors arranged to collect data from various locations within the battery pack. This information can be obtained by the maintenance device100via the coupling to the databus110. During discharge, any abnormal parameters measured by the sensors can be used to control the discharge. For example, if the battery pack104is experiencing excessive heating, the discharge rate can be reduced until the battery temperature returns to an acceptable level. If any of the internal temperature sensors of the battery pack are not functioning, an external battery pack temperature sensor can be used to detect the temperature of the battery pack. Similarly, if cells within the pack are experiencing an abnormally high current discharge, the discharge rate can be reduced. Further still, if such data cannot be obtained because the sensors are damages or the databus is damaged or inaccessible, the maintenance device100can automatically enter a slow/safe discharge state to ensure that the battery is not damaged.

When placing a battery pack104into service, the maintenance device100can identify individual cells or batteries within the pack104which are more or less charged than other cells. Thus, the individual cells or batteries within a pack can be balanced whereby they all have substantially the same charge capacity and/or state of charge as the other cells or batteries within the pack.

In another aspect of the present invention, the maintenance device100is capable of providing a “jump start” to a hybrid electric vehicle102. For example, if the internal combustion engine of a hybrid electric vehicle is started using power directly from the battery pack and if the charge of the battery pack104is too low, there is insufficient energy available to start the engine. The maintenance device100of the present invention can be used to provide sufficient power to a starter motor of the internal combustion engine for starting the engine. Once the internal combustion engine is running, the engine itself is used to charge the battery pack104.

InFIG.3, a voltage sensor232is connected across the wheat stone bridge230. Further, the bridge is optionally connected to electrical ground through switch234. Any voltage detected by voltage sensor232across the bridge230is an indication that there is a current leak between the positive and/or negative terminals of the battery pack104and the electrical ground or chassis of the vehicle102. The voltage sensor232can provide an output to microprocessor130and used to alert an operator of a potentially dangerous situation and indicate that the battery pack104must be disconnected from the vehicle102before further maintenance is performed.

FIG.3also illustrates a relay226which is used to isolate the load resistances222/224from the battery pack until a discharge is commanded by the microprocessor160. The voltage across the battery pack104can be measured using a voltage sensor242connected in series with a resistance240. The output from sensor242is provided to microprocessor160for use in performing maintenance in the battery pack104.

During operation, the components of the device100may experience a great deal of heating. An air flow cooling system can be used to dissipate the heat.FIG.4shows one such configuration. As illustrated inFIG.4, the air flow moves from the low power electronics300, passed the high power electronics302and over the load resistors222A, B and224A, B. The air flow then leaves the housing of the device100. InFIG.4, the air flow is controlled by fans304. The fans304can be controlled using microprocessor160whereby their speed can be adjusted as needed based upon measurements from temperature sensors306which can be placed at various locations within the housing of device100. In this configuration, hot air generated by the load resistance is immediately blown out of the housing rather than past any components.

Some electrical vehicles include what is referred to as a “pre-charge contactor.” The pre-charge contactor can be used to charge capacitances of the vehicle at a slow and controlled rate prior to switching in the main contactor130shown inFIG.1. This prevents excessive current discharge from the battery pack when the main contactor is activated and the pack is directly coupled to the loads of the vehicle including the traction module of the vehicle which is used to control electric motors of the vehicle.

In another aspect, some or all of the information obtained during testing and discharge of a battery pack104is retrieved and stored, for example in the memory164shown inFIG.1, for subsequent access. This information can be offloaded to another device, for example a USB drive or the like, or transmitted over a network connection. This can be particularly useful to examine information retrieved after a vehicle has experienced an accident. The information can be information which is downloaded from the controller108of the vehicle102and may also be information related to how the vehicle battery pack104was discharged and removed of service.

In another aspect, more than one maintenance device100can be coupled to a battery pack104and the multiple devices can be configured to work in tandem. More specifically, the devices100can be coupled using the input/output circuitry184shown inFIG.2whereby one of the devices100operates as a master and one or more other devices100operate as slaves under the control of the master device. This arrangement can be used to increase the rate at which a battery pack104is discharged. In such a configuration, a bridgeable power supply may also be employed.

FIG.5is a simplified diagram showing a removable plug350which can be selectively coupled to battery pack maintenance device100. Removable plug350includes a 5 OHM resistor352configured to connect in parallel through connectors354and356. Removable plug350includes a magnet360configured to actuate a reed switch362. Reed switch362connects to microprocessor160whereby microprocessor160can sense the presence of the plug350. When plug350is coupled to device100, the resistance of one or more of the 33 OHM resistors222A,B and224A,B can be changed because the resistor is in series with the 5 OHM resistor yielding a resistance of about 4.3 OHMs. However, any configuration desired can be provided. This allows the device100to apply a smaller resistance to the battery pack104thereby increasing the discharge rate if desired. For example, a particular battery pack may be of a sufficiently low voltage to allow for an increased current draw to thereby increase the rate at which the battery pack104is discharged. Using reed switch362, the microprocessor160is able to detect the presence of the plug350whereby calculations which rely on the value of applied load resistance can be compensated appropriately. Although only a single resistor352is shown, the plug350may include any number of resistors to be placed in parallel with load resistances in the device100. Preferably plug350includes a cooling mechanism to reduce the heating of resistor352. For example, the plug350may include metal or other heat conducting fins or the like. A fan may also be employed. The fan may be the same cooling fan used in device100or, plug350may optionally include its own fan. In another embodiment, the alternative resistance values are located within the main unit, and are switched into circuit using the removable plug.

FIG.6is a perspective view of another example embodiment of a controllable load170illustrated in a housing402. In the configuration ofFIG.6, resistive elements are provided using a number of resistive coils400. In one example embodiment, these resistive coils can be the type of coils used in consumer applications such as electric clothing dryers. For example, one such coil is rated at approximately 5.3 KW at 240 volts. Note that if the rated voltage is exceeded, the coil will melt and become an open circuit. Further, it is also preferable that the coils400have resistances which are similar. The coils400are carried on supports404preferably made of an electric insulator capable of handling high temperatures. To assist in heat dissipation, an air flow can be provided across the coils400as shown inFIG.4.

FIG.7is a simplified schematic diagram of another example embodiment of controllable load100. In the configuration ofFIG.7, the four coils400illustrated inFIG.6are electrically connected in a series/parallel configuration. In this configuration, switches K1, K2, K3and K4are provided for controlling the resistance provided by controllable load100. These switches can be any type of switch including relays or transistor switches. In one configuration, the switches are manual switches. Switches K1and K2control two parallel legs of the circuit while switches K3and K4control the amount of resistance in series in each leg. In this configuration, a maximum discharge capability of 20 KW is provided if both switches K1and K2are closed and switches K3and K4are open. The B+ and B− connections are used for coupling to the storage battery and fusible links406are provided for safety. In one example configuration, if the voltage across terminals B+ and B− drops below 240 volts DC, switch K3and/or switch K4can then be closed to reduce the resistance applied to battery104and optimize the loading of the battery.FIG.8is a graph showing the loading performance of such an arrangement. As illustrated inFIG.8, the step change occurs when the resistive load provided by controllable load100is decreased, for example, by activating switch K2

As mentioned above, the fans illustrated inFIG.4can be used to provide an air flow across the coils400. In one configuration, all of the fans control circuits and relays may be operated by 12 volt DC and can be powered, for example, by an auxiliary battery or a “cigarette lighter” output from a vehicle such as a tow truck. A double insulation technique can be used proximate the load coils such that any electrical fault, for example a heater coil failure, cannot be conducted to a location outside of the housing402. Optional temperature safety sensors306shown inFIG.4can be used. The temperature sensors306can be provided on both the inlet and the outlet of each heater coil and can be used to detect fan failure or blocked air flow. This configuration can also be used to detect the amount that the air is heated by the coil. In another example configuration, fusible links404may provide hard wired temperature cutout switches to prevent overheating. In such a configuration, when a temperature threshold is reached, the switch will open. Data obtained during discharge can be logged to a memory such as memory164such as a local flash drive or other local storage device. In another configuration, the logged data is sent to a remote location such as cloud storage for analysis. Such records can be of significance for warranty or insurance purposes.

In one configuration, the voltage sensor232is used to detect leakage currents in the battery undergoing discharge. The device can also monitor battery cell voltages and temperatures to ensure that unsafe conditions are not being created during discharge.

The input/output circuitry190can be used to connect to a databus of the vehicle, for example, through an OBDII connection in order to collect information such as VIN, software and hardware version numbers, etc. The device can communicate with the battery ECU (Electronic Control Unit) using any appropriate protocol including CAN, LIN, or others, in order to obtain specific battery information and discharge protocols. The device can be connected as a slave unit to another piece of shop equipment either using a hardwire connection or a wireless connection such as Bluetooth or Wi-Fi. Reverse polarity protection as well as overvoltage protection can be provided. Other safety techniques for electrical potential, temperature and axis points can be fully interlocked to prevent operation of the unit. In one configuration, the input/output184can include a barcode scanner which can then be used to capture specific information such as battery type or serial number as well as vehicle identification number, etc. In another example configuration, input/output circuitry184can include a remote temperature sensor that can be electrically coupled to the discharger to report battery temperature. This is useful when internal battery temperature sensors are damaged or inoperative. The devices are scalable such that multiple controllable loads100can be connected in parallel. Relay contacts can also be provided and available externally to control various circuits on the battery pack undergoing discharge. Additional voltage sensing connections such as those provided by junction box152can be used to monitor various circuits on the battery pack.

Another example configuration includes a high voltage DC to DC converter such as power supply180shown inFIG.2. In such a configuration, the high voltage output from the battery pack can be converted to a lower DC voltage for use in powering the device.

As discussed above, in some configurations the present invention can be arranged to measure a dynamic parameter of the battery pack. In such a configuration, a forcing function is applied to the battery pack and a dynamic parameter such as dynamic conductance, resistance, admittance, etc. can be determined based upon a change in the voltage across the battery pack and the current flowing through the battery pack. The forcing function can be any type of function which has a time varying aspect including an AC signal or a transient signal.

In one aspect, the maintenance device can be configured to “balance” individual cells within the battery pack. The balancing can be performed by selected cells or individual batteries within the pack which have similar storage capacity and state of charge. The charging feature of the device can be used to increase the charge of a cell or battery to that of other cells or batteries. Similarly, the maintenance device can be used to discharge individual cells or batteries to a level similar to that of other cells or batteries within the pack.

When servicing the modules, the internal pack connections are removed, and alternate cabling is supplied from the service/battery maintenance tool. A common application in a service tool is to employ the industry standard interface ICs to monitor the voltage and temperatures and/or apply charging voltages/currents to the battery module.

The problem which exists in the service environment, is that the polarity and voltages on individual pins cannot easily be protected by cable design. For example, the interface connector that mates with one type of battery module, frequently also mates with an alternate battery module that has opposite polarity on the pins, or alternate cell numbering on the pins. Therefore, the absolute maximum limits of the IC can easily be violated by simply plugging in the wrong connector, damaging the circuit, and rendering inoperable the service/battery maintenance tool.

The present invention includes an Intelligent Interface Module that can be connected to any cell configuration, in any polarity, without damage and with full functionality.

In one preferred embodiment, 24 cell voltages will be measured, although the invention can be extended to any number of cell voltages.

The embodiment connects 25 wires to the interface. 24 of these connect to cells and one to electrical ground. Each wire can be connected to any cell node. Any number of cells from 1 to 24 can be connected.

The embodiment measures all 25 wire voltages compared to an internally produced reference voltage. All of the voltages present on the wires can then be measured, and sorted. Once sorted, the deltas of adjacent cells is computed.

The output of the embodiment is then a “virtual” cell ordering can be presented to the service tool. Additional, information can be presented related to which cell node is located on which wire of the connector.

TABLE 1PhysicalMeasuredVirtualVirtualPhysicalPin #VoltagePin #VoltagePin #10.00010.000Measured on Pin212−7.78423.892Measured on Pin143−66.16437.784Measured on Pin64−15.568411.676Measured on Pin35−42.812515.568Measured on Pin226−70.056619.460Measured on Pin257−19.460723.352Measured on Pin188−23.352827.244Measured on Pin169−35.028931.136Measured on Pin1010−46.7041035.028Measured on Pin511−27.2441138.920Measured on Pin23127.7841242.812Measured on Pin91315.5681346.704Measured on Pin1514−73.9481450.596Measured on Pin1115−31.1361554.488Measured on Pin816−50.5961658.380Measured on Pin717−11.6761762.272Measured on Pin418−54.4881866.164Measured on Pin1719−3.8921970.056Measured on Pin2203.8922073.948Measured on Pin1921−77.8402177.840Measured on Pin122−62.2722281.732Measured on Pin2023−38.9202385.624Measured on Pin122411.6762489.516Measured on Pin2425−58.3802593.408Measured on Pin13

Table 1 is an illustration of virtual pin mapping in accordance with one example embodiment of the above mentioned invention. In this configuration, the lowest voltage measured is assumed to be connected to pin 1. However, other configurations can also be employed. By comparing relative voltages between the various pins, as illustrated in the Table, the pin mapping order of the physical pins may be determined.

Once the physical layout of the pin connectors is determined, the maintenance circuitry and techniques discussed herein can be employed. This allows the maintenance device to be employed with different types of battery packs and automatically determine the correct connections in order to service the battery pack.

FIG.8is a simplified schematic diagram of an intelligent interface module500in accordance with one example configuration. Interface module500includes a cable which functions as a junction box152or154and includes a connector502configured to plug into a connector104on the battery pack104. These pins may connect to individual cell or cells within the battery pack104or other components within the battery pack104such as resistance based temperature sensors used to measure temperature within the battery pack104. The particular cable152/154can be selected based upon the configuration of the particular battery pack104under test. This cable152/154includes a connector504which plugs into a connector506of the main unit150.

In addition to determining the “virtual pin” configuration of the battery104, it is also important to determine which of the connectors to the battery pack104connect to individual cells within the pack and which of those connectors (or “pins”) connect to temperature sensors. As illustrated inFIG.8, module500includes a multiplexer510configured to electrically couple to each of the pins presented by the battery pack104. Although a single multiplexer510is shown, any number of multiplexers may be employed. Additionally, a configuration which employs no multiplexers can also be implemented. The multiplexer510operates under the control microprocessor160and selectively couples individual pins from the battery pack104to an amplifier512. The amplifier512also connects to a reference connection which may, for example, be a ground or a pin out provided by the battery pack104, or simply an arbitrary pin out connection from the pack104. The outputs from the amplifier512is provided to an analog to digital converter516which provides a digitized output to microprocessor160.

The microprocessor160can use the multiplexer510to obtain voltage measurements using the amplifier512and analog to digital converter516by selectively connecting to each of the pins presented by the battery pack104. Using these voltage measurements, the microprocessor can determine the virtual pin out connection of the battery pack104as presented by the cable152/154.

One problem that can occur during operation is that a technician can select an incorrect cable used to test the individual batteries within the pack104. If only voltages are being measured, this may result in error in the measurements. However, if the main unit150expects that certain pins connect to temperature sensors, the device may be damaged if a pin output from pack104which carries a battery voltage is coupled to temperature sensing circuitry. Thus, the microprocessor160is able to determine which of the pins are not energized and thereby determine that the particular pin can be coupled to temperature measurement circuitry without damage. Further, the various measured voltages, including the pins that have no voltage, can be used by the microprocessor160to ensure that the proper cable152/154is being used to connect to the battery pack104. If the pin out does not match the expected configuration, the microprocessor can provide an output to an operator using for example operator I/O182to indicate that an error has occurred. The expected cable can be provided as an output to the operator in order to correct the error. This could also be an indication that the operator has misidentified the type of battery pack being tested. In one aspect, a memory590is provided in the cable which carries information used to identify the cable and what type of battery pack104the cable is configured to connect to.

As shown inFIG.8, connection headers520are used to provide an electric connection from the individual pins to temperature measurement circuitry550shown inFIG.9. Temperature measurement circuitry550includes a current source552which injects a current I into a resistance based temperature sensor in the battery pack104. The resistance of the temperature sensor changes based upon temperature and thus the resultant voltage drop across its pin connection changes. An amplifier554is arranged to measure this voltage drop and provides an output to an analog to digital converter556. The digitized output indicative of battery temperature is then provided to microprocessor160.

As illustrated inFIG.8, the connection between headers520and the individual pins are controlled by switches508which operate under the control of microprocessor160. Microprocessor160only engages those switches which are known to provide an electrical connection to a temperature sensor thereby preventing a voltage from being applied to the temperature measurement circuitry550illustrated inFIG.9. The temperature information can be used to detect a failure or impending failure in the battery pack104including a thermal run-away condition.

An optional temperature sensor594can also be provided in the cable152/154or main unit. The sensor594can be an infrared temperature sensor, or a sensor which requires a physical coupling. The sensor can be positioned adjacent the battery pack104to detect excessive temperatures which may indicate a failure or impending failure in the pack104. For example, a cell with a high resistance may cause heating to occur. The information from the internal or external temperature sensors can be used to control the charging of the pack104and provided as a diagnostic output, for example, to an operator.

In another aspect, the device ofFIG.1includes an ambient temperature sensor. The microprocessor can use information from the ambient temperature sensor in determining how the battery pack should be discharged. For example, if the ambient temperature is high, the discharge rate can be reduced. In another example, if the ambient temperature deviates from a nominal value, say 25° C.′, the discharge rate can be adjusted accordingly. More specifically, the discharge rate can be reduced for certain battery packs during cold temperatures.

During discharge of the battery pack, the discharge profile can be monitored to ensure proper operation. For example, if the voltage of the battery suddenly drops, this can be an indication that a component within the battery has failed or a short circuit has occurred.

Different types of junction boxes and connection cables can be used based upon the particular type of vehicle and battery pack under maintenance. The microprocessor can provide information to the operator prompting the operator to use the appropriate junction box or cable. This can be based upon the operator inputting the vehicle identification number (VIN) to the microprocessor, or other identifying information including an identification number associated with the battery pack. During discharging of the battery pack, the microprocessor can also provide information to the operator which indicates the time remaining to complete the discharge. The microprocessor160can also detect if the correct junction box and cable have been coupled to the device and to the battery pack for the particular battery pack and vehicle under maintenance. Information can be provided to the operator if the wrong cabling or junction box has been employed.

The device of the present invention can be used with battery packs which have been removed from a vehicle as well as individual batteries, or groups of batteries, within a pack. For example, a battery pack typically includes a battery connector assembly which is used by the vehicle102to couple to the battery pack104. However, when the battery pack104is removed from the vehicle102, the device100can directly couple to this battery connector assembly and thereby charge or discharge the battery pack, perform tests on the battery pack, interact with devices on the battery pack including sensors, controllers, etc. As discussed above, the device100can include multiple connectors for use in connecting the low voltage junction box152and/or the high voltage junction box154to the vehicle102and/or battery pack104. This allows the device100to easily be modified to interact with different types of batteries or vehicles by simply selecting the appropriate connector. In one configuration, the connectors include some type of identifier which can be read by the device100whereby the microprocessor160and device100can receive information to thereby identify the type of connector in use. This allows the microprocessor100to know what types of information or tests may be available through the various connectors. In another example, the operator uses operator I/O182shown inFIG.2to input information to the microprocessor160related to the type of connector(s) being used. In another example embodiment, the microprocessor160may receive information which identifies the type of vehicle or battery on which maintenance is being performed. This information can be input by an operator using the operator I/O182, or through some other means such as by communicating with the databus of the vehicle, scanning a barcode or other type of input, etc. Based upon this information, the microprocessor can provide an output to the operator using operator I/O182which informs the operator which type of interconnect cable should be used to couple the low voltage junction box152and/or the high voltage junction box154to the vehicle and/or battery pack.

The operator I/O182may include a display along with a keypad input or touchscreen. The input may take various formats, for example, a menu driven format in which an operator moves through a series of menus selecting various options and configurations. Similarly, the operator I/O182can be used by the microprocessor160to step the operator through a maintenance procedure. In one configuration, the memory164is configured to receive a user identification which identifies the operator using the equipment. This can be input, for example, through operator I/O182and allows information related to the maintenance being performed to be associated with information which identifies a particular operator. Additional information that can be associated with the maintenance data include tests performed on the vehicle and/or battery, logging information, steps performed in accordance with the maintenance, date and time information, geographical location information, environmental information including temperature, test conditions, etc., along with any other desired information. This information can be stored in memory164for concurrent or subsequent transmission to another device or location for further analysis. Memory164can also store program instructions, battery parameters, vehicle parameters, testing or maintenance information or procedures, as well as other information. These programming instructions can be updated, for example, using I/O184or186, through an USB flash drive, SD card or other memory device, or through some other means as desired. This allows the device100to be modified, for example, if new types of vehicles or battery pack configurations are released, if new testing or maintenance procedures are desired, etc.

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No. 16/253,549, filed Jan. 22, 2019, entitled HYBRID AND ELECTRIC VEHICLE BATTERY PACK MAINTENANCE DEVICE; U.S. Ser. No. 16/297,975, filed Mar. 11, 2019, entitled HIGH USE BATTERY PACK MAINTENANCE; U.S. Ser. No. 16/695,705, filed Nov. 26, 2019, entitled BATTERY RATING VERSUS OEM SPECIFICATION; U.S. Ser. No. 16/943,120, filed Jul. 30, 2020 entitled TIRE TREAD GAUGE USING VISUAL INDICATOR; U.S. Ser. No. 17/086,629, filed Nov. 2, 2020, entitled HYBRID AND ELECTRIC VEHICLE BATTERY PACK MAINTENANCE DEVICE; U.S. Ser. No. 147/088,824, filed Nov. 4, 2020, entitled SYSTEM FOR CHARGING A SERIES OF CONNECTED BATTERIES; U.S. Ser. No. 17/090,129, filed Nov. 5, 2020 entitled BATTERY PACK MAINTENANCE SYSTEM; all of which are incorporated herein by reference in their entireties.