JP2010273417A - Electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle that continues running only by an output of a normal battery module even when a battery fails. <P>SOLUTION: A battery control unit includes: a state detecting section that detects the state of each of battery modules, a failure determining section that identifies an abnormal battery module based on the state of each battery module detected by the state detecting section, and a module switching control section that controls a battery module switching section so as to disconnect the abnormal battery module from at least a path for supplying power to a motor. The battery control unit calculates an output upper limit value based on the normal battery modules. When the output upper limit value is equal to or higher than a predetermined value, the module switching control section controls the module switching section so as to disconnect the abnormal battery module from the power supply path. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric vehicle including an electric motor driven by electric power supplied from a battery and capable of traveling with power from the electric motor.

  Vehicles such as EV (Electric Vehicle) and HEV (Hybrid Electrical Vehicle) are equipped with a battery for supplying electric power to an electric motor or the like. Such a battery is configured by connecting a plurality of storage batteries such as lithium ion batteries and nickel metal hydride batteries to form a battery module and connecting a plurality of the battery modules.

  A battery mounted on a vehicle gradually deteriorates due to being left on the vehicle for a long period of time or repeated charging and discharging. Conventionally, when an abnormality of a battery due to such deterioration or other failure is detected, a warning is given to the user, and then the battery is disconnected from the electric motor and generator for running to stop using the battery. It is known (see, for example, Patent Document 1). Moreover, it is known to short-circuit a failed cell (battery module) for a battery used in an unmanned operation system such as an artificial satellite (see, for example, Patent Document 2).

JP 2009-60695 A JP-A-63-245228

  As described above, the battery mounted on the vehicle is configured by connecting a plurality of battery modules in series or in parallel. Therefore, even when an abnormality occurs in the battery, it may be possible to continue traveling using only the normal battery module by disconnecting only the abnormal battery module from the energization path.

  However, there is a possibility that an output necessary for traveling of the vehicle cannot be obtained with only a normal battery module depending on the scale and situation of the abnormality that has occurred in the battery. Therefore, before disconnecting the abnormal battery module, it is necessary to determine whether it is possible to continue traveling safely only by the output of the normal battery module.

  The present invention has been made in view of the above-described problems, and its purpose is to continue traveling safely only by the output of a normal battery module even when an abnormality occurs in a battery mounted on a vehicle. It is providing the electric vehicle which can be performed.

  In order to achieve the above object, the invention according to claim 1 includes a plurality of battery modules, and a module switching unit (for example, a bypass switch 131 in an embodiment described later) that switches the energization mode of the plurality of battery modules. Battery (for example, a battery 101 in an embodiment described later), a battery control unit (for example, a battery ECU 119 in an embodiment described later), and an electric motor (for example, driven by electric power supplied from the battery) An electric motor 105 in an embodiment described later, and is an electric vehicle that can be driven by power from the electric motor, wherein the battery control unit detects a state of each of the plurality of battery modules. (For example, a state detection unit 141 in an embodiment described later) and the state detection unit Based on the detected state of each battery module, an abnormality determination unit that identifies an abnormal battery module (for example, an abnormality determination unit 143 in an embodiment described later), and the abnormal battery module at least from the energization path to the motor A module switching control unit (for example, a module switching control unit 145 in an embodiment described later) that controls the module switching unit to be disconnected, and the battery control unit is a normal battery excluding the abnormal battery module An output upper limit value based on a module is calculated, and the module switching control unit controls the module switching unit to disconnect the abnormal battery module from the energization path when the output upper limit value is equal to or greater than a predetermined value. And

  According to a second aspect of the present invention, in the electric vehicle according to the first aspect, the module switching control unit is configured to disconnect all of the battery modules from the energization path when the output upper limit value is less than a predetermined value. The switching unit is controlled.

  According to a third aspect of the present invention, in the electric vehicle according to the first or second aspect, a generator that generates electric power by driving an internal combustion engine (for example, a generator 109 in an embodiment described later), and an electric motor control that controls the electric motor. (For example, a motor ECU 109 in an embodiment described later) and a generator control unit (for example, a generator ECU 109 in an embodiment described later) for controlling the generator, and the battery control unit An upper limit value and a lower limit value of a state of charge of a battery composed of battery modules are calculated, and the motor control unit and the generator control unit determine the motor and the generator based on the upper limit value and the lower limit value of the charge state. It is characterized by controlling.

  According to a fourth aspect of the present invention, in the electric vehicle according to any one of the first to third aspects, the battery control unit includes a box opening detection unit that detects that a box that houses the battery is opened. When the opening of the box is detected, the module switching control unit controls the module switching unit to disconnect all of the battery modules from the energization path.

  According to a fifth aspect of the present invention, in the electric vehicle according to any one of the first to fourth aspects, the battery is a connection plug that can be connected to a commercial power source to charge the battery (for example, in an embodiment described later). When the connection plug is connected to the commercial power source, the battery control unit controls the battery according to the state of each battery module.

  The invention according to claim 6 is the electric vehicle according to any one of claims 1 to 5, wherein the plurality of battery modules are connected in series, and the module switching unit is a bypass switch ( For example, it is a bypass switch 131) in an embodiment described later.

  According to a seventh aspect of the present invention, in the electric vehicle according to any one of the first to fifth aspects, the plurality of battery modules are connected in parallel, and the module switching unit selects a module selection switch ( For example, it is a module selection switch 135) in an embodiment described later.

  According to the first aspect of the present invention, when the output upper limit value based on the normal battery module is equal to or greater than the predetermined value, only the abnormal battery module is disconnected from the energization path, thereby safely traveling with the normal battery module. The operation reliability of the vehicle can be improved.

  According to the invention of claim 2, when the output upper limit value based on a normal battery module is less than a predetermined value, safety can be improved by disconnecting all battery modules from the energization path.

  According to the invention of claim 3, by controlling the electric motor and the generator based on the upper limit value and the lower limit value of the state of charge of the battery composed of a normal battery module, it is possible to appropriately travel according to the state of the battery. It can be carried out.

  According to the invention of claim 4, safety can be improved by disconnecting all battery modules from the energization path when the box is opened.

  According to invention of Claim 5, it can charge according to the state of each battery module.

  According to the sixth and seventh aspects of the invention, an abnormal battery module can be easily separated from the energization path.

It is a block diagram which shows the internal structure of HEV of a series parallel system. It is a block diagram which shows schematic structure of the battery module switching process system of the electric vehicle concerning embodiment of this invention. It is a flowchart explaining the switching operation of a battery module. It is the schematic which shows an example of the battery in which each battery module was connected in series. It is a flowchart explaining the operation | movement at the time of the maintenance of a battery. It is a flowchart which shows the operation | movement at the time of battery charge by a connection plug. It is the schematic which shows an example of the battery with which each battery module was connected in parallel.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

  A HEV (Hybrid Electrical Vehicle) includes an electric motor and an internal combustion engine, and travels by the driving force of the electric motor and / or the internal combustion engine according to the traveling state of the vehicle. There are two types of HEVs: a series method and a parallel method. A series-type HEV travels by the driving force of an electric motor powered by a battery. The internal combustion engine is used only for power generation, and the electric power generated by the driving force of the internal combustion engine is charged in the battery or supplied to the electric motor. On the other hand, the parallel HEV travels by the driving force of one or both of the electric motor and the internal combustion engine. A series-parallel HEV that combines both systems is also known.

  Hereinafter, although a series system HEV will be described, the present invention is also applicable to other system HEVs.

  FIG. 1 is a block diagram showing the internal configuration of a series-type HEV. 1 includes a battery (BATT) 101, a first inverter (first INV) 103, an electric motor (MOT) 105, and a multi-cylinder internal combustion engine (ENG). ) 107, generator (GEN) 109, second inverter (second INV) 111, gear box 115, management ECU (MG ECU) 117, battery ECU (BATT ECU) 119, motor ECU (MOT ECU) ) 121, a generator ECU (BATT ECU) 123, and an engine ECU (ENG ECU) 125.

  In the vehicle shown in FIG. 1, the driving force from the electric motor 105 using the battery 101 as a power source is transmitted to the driving wheels 129 via the gear box 115. The traveling mode of the vehicle is “EV traveling” or “series traveling”. During EV travel, the vehicle travels by the driving force of the electric motor 105 that is driven by the supply of power from the battery 101. Further, at the time of series traveling, the vehicle travels by the driving force of the electric motor 105 that is driven by the supply of power from the battery 101 and the supply of electric power generated by the generator 109 by driving the internal combustion engine 107.

  The battery 101 is composed of a plurality of battery modules connected in series, housed in a box, and supplies a high voltage of, for example, 100 to 200V. Each battery module is configured by connecting a plurality of storage batteries such as lithium ion batteries in series.

  First inverter 103 converts a DC voltage from battery 101 into an AC voltage and supplies a three-phase current to electric motor 105. The electric motor 105 generates power (torque) for the vehicle to travel. Torque generated by the electric motor 105 is transmitted to the drive shaft 127 of the drive wheel 129 via the gear 115.

  A multi-cylinder internal combustion engine (hereinafter simply referred to as “internal combustion engine”) 107 generates power (torque), and this power is consumed by the generator 109. The generator 109 is directly connected to the internal combustion engine 107.

  The generator 109 is driven by the internal combustion engine 107 to generate electric power. Electric power generated by the generator 109 is charged in the battery 101 or supplied to the electric motor 105. The second inverter 111 converts the AC voltage generated by the generator 109 into a DC voltage. The electric power converted by the second inverter 111 is charged in the battery 101 or supplied to the electric motor 105 via the first inverter 103.

  The gear box 115 is a transmission that converts the driving force from the electric motor 105 into a rotation speed and torque at a desired gear ratio and transmits the converted torque to the drive shaft 127. The gear box 115 and the rotor of the electric motor 105 are directly connected.

  The management ECU 117 performs switching between EV travel and series travel, and controls the electric motor 105 and the internal combustion engine 107. The management ECU 117 also includes a requested driving force sensor (not shown) that detects information from a vehicle speed sensor (not shown) that detects the speed of the vehicle and a driving force of the vehicle that is requested by the driver, such as the accelerator opening. ) Is input.

  The motor ECU 121 controls the electric motor 105 according to an instruction from the management ECU 117. The generator ECU 123 controls the generator 109 according to an instruction from the management ECU 117. The engine ECU 125 controls the start and stop of the internal combustion engine 107, throttle valve opening / closing control and fuel injection control in each cylinder, and the number of revolutions of the crankshaft of the internal combustion engine 107 in accordance with instructions from the management ECU 117.

  FIG. 2 is a block diagram showing a schematic configuration of the battery module switching processing system of the electric vehicle according to the present embodiment. In the present embodiment, the battery 101 includes a plurality of battery modules connected in series and housed in a box, and includes a bypass switch 133 and a connection plug 133 for connecting to a commercial power source. The battery ECU 119 includes a state detection unit 141, an abnormality determination unit 143, a module switching control unit 145, and a box opening detection unit 147. The management ECU 117 includes a motor (MOT) torque calculator 151, a generator (GEN) torque calculator 153, and an engine (ENG) torque calculator 155.

  The state detection unit 141 sets the temperature and charge state (SOC: State Of Charge, 100% and 0%) of each battery module of the battery 101, and sets the remaining capacity of the battery to the standard. Status), voltage, current, and the like. The abnormality determination unit 143 identifies a battery module in which an abnormality has occurred based on the state of each battery module. The module switching control unit 145 disconnects the abnormal battery module from the energization path by the bypass switch 133. The box opening detection unit 147 detects the opening of the box in which each battery module is stored.

  The motor torque calculation unit 151 performs torque calculation based on the output upper limit value of a normal battery module. Generator torque calculation unit 153 and engine torque calculation unit 155 perform torque calculation based on the upper and lower limit values of the SOC of a normal battery module.

  FIG. 3 is a flowchart showing the switching operation of the battery module according to the present embodiment. As shown in FIG. 3, first, the state detector 141 detects the state of the battery 101 (step S1).

  In the state detection of the battery 101, the state detection unit 141 detects the current and voltage, the upper and lower limit values of the SOC, the temperature, etc. for each of the i battery modules M1, M2,..., Mi connected in series. To do. These pieces of information detected by the state detection unit 141 are sent to the abnormality determination unit 143.

  The abnormality determination unit 143 determines whether or not an abnormality has occurred in any of the battery modules 101 based on the current, voltage, temperature, and the like of each of the battery modules M1, M2,. ). If there is no abnormality in the battery modules and all the battery modules are normal, the process ends.

  If it is determined in step S2 that an abnormality has occurred in any of the battery modules, the abnormality determination unit 143 identifies the abnormal battery module and informs the management ECU 117 that the abnormality has occurred in the battery module. send. Next, the management ECU 117 lights an alarm to warn the user that an abnormality has occurred in the battery 101 (step S3).

  Based on the state of each battery module detected by the state detection unit 141, the battery ECU 119 calculates an output upper limit value A only for normal battery modules excluding abnormal battery modules (step S4). Further, the battery ECU 119 calculates the upper and lower limit values of the SOC based only on normal battery modules (step S5). The calculated output upper limit value A and SOC upper and lower limit values are sent to the management ECU 117.

  The management ECU 117 determines whether or not the output upper limit value A ≧ predetermined value (step S6). This predetermined value is a lower limit value of the output necessary for driving the vehicle safely. Therefore, when the output upper limit value A ≧ predetermined value, the vehicle can be continuously driven by the output from only the normal battery module. In this case, the module switching control unit 145 turns on the bypass switch 131 of the abnormal battery module to short-circuit the circuit, and disconnects the abnormal battery module from the energization path (step S7).

  Normally, the torque generated by the electric motor 105 is determined according to the amount of depression of the accelerator pedal based on the output when the battery 101 is operating normally. However, if normal torque control is performed when an abnormal battery module is disconnected, there is a possibility that the output upper limit value A by only a normal battery module may be exceeded. In order to prevent this, the motor torque calculation unit 153 calculates the motor torque based on the output upper limit value A only from the normal battery module (step S8). The motor torque calculated based on the output upper limit value A only from the normal battery module is sent to the motor ECU 121.

  Further, the generator torque calculation unit 155 and the engine torque calculation unit 157 calculate the generator torque and the engine torque, respectively, based on the upper and lower limit values of the SOC of the battery composed only of normal battery modules (step S9). The generator torque and engine torque calculated here are sent to the generator ECU 123 and the engine ECU 125. With these calculations, the vehicle can run normally only with a normal battery module, and the process ends.

  If it is determined in step S6 that the output upper limit value A <predetermined value, the travel cannot be continued only with a normal battery module, and therefore the module switching control unit 145 turns on all the bypass switches 131. (Step S10). As a result, all the battery modules are disconnected from the energization path, the vehicle stops (step S11), and the process ends.

  FIG. 4 is a diagram illustrating an operation of the bypass switch 131 that short-circuits the battery module. In FIG. 4A, three battery modules M1, M2, and M3 are connected in series to the energization path. In (b), the bypass switches 131 are all turned on, and the battery modules M1, M2, and M3 are all disconnected from the energization path.

  In (c), an abnormality has occurred in the battery module M1, and the battery module M1 is disconnected from the energization path by turning on the bypass switch 131 of the battery module M1. In (d), an abnormality has occurred in the battery module M2, and the battery module M2 is disconnected from the energization path by turning on the bypass switch 131 of the battery module M2. In (e), an abnormality has occurred in the battery module M3, and the battery module M3 is disconnected from the energization path by turning on the bypass switch 131 of the battery module M3.

  As described above, according to the vehicle according to the present embodiment, when the output upper limit value based on the normal battery module is equal to or greater than the predetermined value, only the abnormal battery module can be easily separated from the energization path. It is possible to continue traveling safely with a normal battery module. Further, by controlling the traveling motor and the engine-driven generator based on the upper limit value and the lower limit value of the normal state of the battery module, traveling based on the actual battery state becomes possible. Therefore, the operational reliability and safety of the vehicle can be improved.

  Further, the battery module switching processing system of the vehicle according to the present embodiment can be used as a safety device that disconnects all the battery modules from the energization path when the box for storing the battery modules is opened during maintenance of the battery 101. . FIG. 5 is a flowchart for explaining the operation during maintenance of the battery 101. First, the box opening detection unit 147 determines whether or not a box containing a plurality of battery modules has been opened (step S21). If the box is not opened, the process ends. If it is determined that the box has been opened, the module switching control unit 145 turns on all the bypass switches 131 (step S22). Thereby, all the battery modules are disconnected from the energization path, and the process ends.

  As described above, according to the vehicle of this embodiment, safety can be improved by disconnecting all battery modules from the energization path when the box is opened.

  Further, the battery module switching processing system of the vehicle according to the present embodiment can perform charging according to the state of each battery module when charging is performed by connecting a commercial power source to the connection plug 133. FIG. 6 is a flowchart showing an operation during charging by the connection plug 133. First, the management ECU 117 determines whether or not the connection plug 133 is connected to a commercial power supply (step S31). If the connection plug 133 is not connected to a commercial power source, the process ends.

  When it is determined that the connection plug 133 is connected to the commercial power source, the state detection unit 141 detects the state of the battery 101 (step S32). The state detector 141 detects states such as current and voltage, SOC upper and lower limit values, and temperature for each of the i battery modules M1, M2,..., Mi connected in series. These pieces of information detected by the state detection unit 141 are sent to the abnormality determination unit 143.

  The abnormality determination unit 143 determines whether or not an abnormality has occurred in any of the battery modules 101 based on the current, voltage, temperature, and the like of each of the battery modules M1, M2,... Mi (step S33). ). If there is no abnormality in the battery modules and all the battery modules are normal, the process ends.

  When it is determined that an abnormality has occurred in any of the battery modules, the module switching control unit 145 turns on the bypass switch 131 of the abnormal battery module (step S34). As a result, the abnormal battery module is disconnected from the energization path, and the process ends. This makes it possible to charge only normal battery modules.

  In addition, when charging, by controlling the bypass switch 131, different charging may be performed for each battery module according to the SOC of each battery module detected by the state detection unit 141.

  As described above, according to the vehicle according to the present embodiment, charging can be performed according to the state of each battery module.

  As a modification of the present embodiment, the battery 101 may be composed of a plurality of battery modules connected in parallel as shown in FIG. In FIG. 7A, the three battery modules M1, M2, and M3 are connected in parallel to the energization path. In (b), the battery modules M1, M2, and M3 are all disconnected from the energization path.

  In this modification, the battery module is switched by the module selection switch 135. When an abnormality occurs in the battery module M3, as shown in (c), the battery module M3 can be disconnected from the energization path by turning on the module selection switch 135 of the battery module M3.

  The present invention is not limited to the embodiments described above, and modifications, improvements, and the like can be made as appropriate.

101 Battery (BATT)
105 Electric motor (MOT)
107 Multi-cylinder internal combustion engine (ENG)
109 Generator (GEN)
117 Management ECU (MG ECU)
119 Battery ECU (BATT ECU)
121 Motor ECU (MOT ECU)
125 Engine ECU (ENG ECU)
131 Bypass switch

Claims (7)

A battery having a plurality of battery modules and a module switching unit that switches a current-carrying mode of the plurality of battery modules;
A battery control unit for controlling the battery;
An electric motor driven by electric power supplied from the battery, and an electric vehicle capable of traveling by power from the electric motor,
The battery control unit
A state detector for detecting the state of each of the plurality of battery modules;
Based on the state of each battery module detected by the state detection unit, an abnormality determination unit that identifies an abnormal battery module;
A module switching control unit that controls the module switching unit so as to disconnect the abnormal battery module from at least the energization path to the electric motor,
The battery control unit calculates an output upper limit value based on normal battery modules excluding the abnormal battery module, and the module switching control unit is configured to output the abnormal battery module when the output upper limit value is a predetermined value or more. The module switching unit is controlled so as to be disconnected from the energization path.   2. The electric vehicle according to claim 1, wherein the module switching control unit controls the module switching unit to disconnect all of the battery modules from the energization path when the output upper limit value is less than a predetermined value. . A generator for generating electric power by driving an internal combustion engine; an electric motor controller for controlling the electric motor; and a generator controller for controlling the electric generator;
The battery control unit calculates an upper limit value and a lower limit value of a state of charge of a battery composed of the normal battery module, and the electric motor control unit and the generator control unit are an upper limit value and a lower limit value of the charge state. The electric vehicle according to claim 1, wherein the electric motor and the generator are controlled based on the motor. The battery control unit has a box opening detection unit that detects that a box containing the battery is opened,
4. The module switching control unit according to claim 1, wherein when the opening of the box is detected, the module switching control unit controls the module switching unit to disconnect all of the battery modules from the energization path. 5. The electric vehicle described. The battery has a connection plug connectable with a commercial power source for charging the battery,
5. The electric vehicle according to claim 1, wherein when the connection plug is connected to the commercial power source, the battery control unit controls the battery according to a state of each battery module. 6. .   6. The electric vehicle according to claim 1, wherein the plurality of battery modules are connected in series, and the module switching unit is a bypass switch provided in each module.   The electric vehicle according to any one of claims 1 to 5, wherein the plurality of battery modules are connected in parallel, and the module switching unit is a module selection switch that selects each module.

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