JP2016025790A - Power storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of fuel economy due to an input-output limit associated with the suppression of a temperature rise at an electrified component.SOLUTION: A power storage system has a controller for performing charge-discharge control in accordance with a temperature at an electrified component electrically connected to a power storage device. The controller includes: an evaluation value calculation part for calculating an evaluation value for evaluating a temperature state of the electrified component on the basis of a current value detected when charging-discharging the power storage device; a change part for limiting an upper limit value of discharging or charging power of the power storage device in the case of the evaluation value exceeding a threshold; and an atmospheric temperature state determination part for counting low-temperature continuation time in which the electrified component is in the state of being at a given atmospheric temperature or lower until an ignition switch of a vehicle is turned on. In a case where the low-temperature continuation time is equal to or more than a given period of time before the ignition switch of the vehicle is turned on, the evaluation value calculation part calculates the evaluation value smaller for a certain period of time after the ignition switch of the vehicle has been turned on.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a power storage system including a power storage device that supplies electric power to a vehicle driving motor, and more particularly to a technique for controlling charge / discharge of a power storage device.

  A battery mounted on a hybrid vehicle, an electric vehicle, or the like includes current-carrying parts such as a relay, a fuse, and a harness. When a current flows through the battery, Joule heat is generated in these energized parts. If the temperature of the current-carrying component rises, it may not function normally. Therefore, it is necessary to control the charge / discharge of the battery from the viewpoint of appropriately protecting the current-carrying component (for example, Patent Document 1).

JP 2009-005577 A

  For example, Patent Document 1 calculates an evaluation value (evaluation function) for evaluating a temperature rise of a current-carrying component from a charge / discharge current, and limits the upper limit value of battery input / output power based on the evaluation value. Temperature rise is suppressed. On the other hand, if the input / output power of the battery is limited to be low, drivability and fuel consumption are deteriorated. For this reason, it is preferable to delay as much as possible the timing at which the input / output restriction associated with the suppression of the temperature rise of the energized parts intervenes.

  Here, although the evaluation of the temperature rise of the energized component is based on the square value of the current, the temperature of the energized component is affected by the environmental temperature, that is, the ambient temperature around the energized component. For this reason, the time during which the same current can be applied (energization possible time) differs between the low and high ambient temperatures, and the low temperature rise rate is low even when the same current is applied, resulting in a longer time. Can be energized.

  However, in Patent Document 1, the temperature rise is evaluated based on the square value of the current regardless of the ambient temperature of the energized component, and when the evaluation value exceeds the threshold, the upper limit value of the input / output power is limited to be low. For this reason, even when the ambient temperature of the current-carrying parts is low and actually the temperature of the current-carrying parts is not high, the same evaluation value is calculated as when the ambient temperature of the current-carrying parts is high. Resulting in.

  Accordingly, an object of the present invention is to provide a power storage system capable of performing input / output control accompanying suppression of a temperature rise of a subsequent energized component according to a temperature environment of the energized component before the ignition switch of the vehicle is turned on. There is.

  The present invention is a power storage system including a power storage device that supplies power to a vehicle driving motor, a current sensor that detects a charge / discharge current of the power storage device, a first temperature sensor that detects a temperature of the power storage device, A second temperature sensor that detects an intake temperature of air for temperature adjustment supplied to the power storage device; and a controller that performs charge / discharge control according to the temperature of a current-carrying component electrically connected to the power storage device.

  The controller, based on the current value detected during charging and discharging of the power storage device, an evaluation value calculation unit that calculates an evaluation value for evaluating the temperature state of the energized component, and when the evaluation value exceeds a threshold value, Based on the change unit that limits the upper limit value of the discharge power or charge power of the power storage device, and the temperature of the power storage device and the intake air temperature from when the vehicle ignition switch is turned on until the ignition switch is turned on An ambient temperature state determination unit that determines whether or not a component is in a state below a predetermined ambient temperature and counts a duration during which the energized component is below the ambient temperature until the vehicle ignition switch is turned on. And having.

  Then, the evaluation value calculation unit, when the duration of the state below the ambient temperature before the ignition switch of the vehicle is turned on is a predetermined time or more, up to a certain time after the ignition switch of the vehicle is turned on In the meantime, the evaluation value is calculated to be smaller than when the duration time in the state below the ambient temperature is shorter than the predetermined time or when the energized component is not in the state below the ambient temperature.

  According to the present invention, the ambient temperature of the energized component before the ignition switch of the vehicle is turned on is grasped, and if the energized component is below a predetermined ambient temperature for a long time, the temperature environment of the energized component due to charge / discharge Is determined to be in a low temperature state, and the temperature environment of the energized component is not determined to be in a low temperature state (when the duration of the state below the ambient temperature is shorter than the predetermined time, or the energized component is not below the ambient temperature The evaluation value is calculated to be smaller than (when). For this reason, the evaluation value is calculated to be small until a certain time after the ignition switch of the vehicle is turned on according to the low temperature environment where the energization time for the same current becomes long. The time until the input / output restriction intervenes with the suppression of the temperature rise of the energized parts can be delayed. Accordingly, it is possible to suppress drivability deterioration and fuel consumption deterioration.

It is a figure which shows the structure of the vehicle which mounts the battery system and battery system in Example 1. FIG. 1 is a diagram illustrating a cooling structure of a battery system in Example 1. FIG. 3 is a flowchart illustrating a process for controlling charging / discharging of the assembled battery of Example 1. It is a figure which shows the relationship between the evaluation value F (N) in Example 1, an input-output restriction | limiting, and the temperature of an electricity supply component. It is a figure which shows the map of the smoothing coefficient K for calculating the evaluation value F (N) of Example 1, and is a figure which shows the relationship between the electric current value according to the temperature environment of electricity supply components, and its energization possible time. It is a flowchart which shows the low temperature atmosphere determination process of the electricity supply components in which the ignition switch in Example 1 is OFF. It is a flowchart which shows the detailed process of step S103 of FIG.

  Examples of the present invention will be described below.

Example 1
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a configuration of a battery system. The battery system shown in FIG. 1 is mounted on a vehicle. Vehicles include hybrid cars and electric cars. A hybrid vehicle is a vehicle provided with a fuel cell, an internal combustion engine, etc. in addition to the assembled battery as a power source for running the vehicle. An electric vehicle is a vehicle that includes only an assembled battery as a power source for the vehicle. Hereinafter, a battery system mounted on a hybrid vehicle will be described as an example.

  The assembled battery 1 (corresponding to a power storage device) has a plurality of unit cells 10 electrically connected in series. The number of unit cells 10 constituting the assembled battery 1 can be appropriately set based on the required output of the assembled battery 1 and the like. The assembled battery 1 may include a plurality of unit cells 10 electrically connected in parallel.

  As the unit cell 10, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor (capacitor) can be used instead of the secondary battery.

  The assembled battery 1 is connected to the inverter 24 through a positive electrode line PL and a negative electrode line. System main relays SMR-B and SMR-G are provided on the positive line PL and the negative line NL, respectively. A system main relay SMR-P and a current limiting resistor R are connected in parallel to the system main relay SMR-G, and the system main relay SMR-P and the current limiting resistor R are connected in series.

  When connecting the assembled battery 1 to the inverter 24, the controller 30 first switches the system main relay SMR-B from off to on and switches the system main relay SMR-P from off to on. Thereby, it can suppress that an electric current flows into the current limiting resistance R, and an inrush current flows.

  Next, the controller 30 switches the system main relay SMR-P from on to off after switching the system main relay SMR-G from off to on. Thereby, the connection between the assembled battery 1 and the inverter 24 is completed, and the battery system shown in FIG. 1 is in the activated state (Ready-On). Information relating to the controller 30 and on / off of the ignition switch of the vehicle (IG-ON / IG-OFF) is input, and the controller 30 activates the battery system in response to the ignition switch switching from OFF to ON.

  On the other hand, when the ignition switch is switched from on to off, the controller 30 switches the system main relays SMR-B and SMR-G from on to off. Thereby, the connection between the assembled battery 1 and the inverter 24 is cut off, and the battery system is in a stopped state (Ready-Off).

  The inverter 24 converts the DC power output from the assembled battery 1 into AC power, and outputs the AC power to the motor / generator MG2. The motor generator (corresponding to the traveling motor of the present invention) MG2 receives the AC power output from the inverter 24 and generates kinetic energy (power) for running the vehicle. Motor generator MG2 is connected to a drive shaft connected to drive wheel 25 via transmission (transmission) TM, and the power of motor generator MG2 is transmitted to the drive shaft via transmission TM and is driven by the drive shaft. It is transmitted to the wheel 25. By transmitting the power generated by the motor / generator MG2 to the drive wheels 25 via the transmission TM, the vehicle can be driven using the electric power of the assembled battery 1.

  The power split mechanism 26 transmits the power of the engine 27 to the drive wheels 25 or to the motor / generator MG1. Motor generator MG1 receives power from engine 27 to generate power. The electric power (AC power) generated by the motor / generator MG 1 is supplied to the motor / generator MG 2 or supplied to the assembled battery 1 via the inverter 24. If the electric power generated by the motor / generator MG1 is supplied to the motor / generator MG2, the driving wheel 25 can be driven by the kinetic energy generated by the motor / generator MG2. If the electric power generated by the motor / generator MG1 is supplied to the assembled battery 1, the assembled battery 1 can be charged.

  When the vehicle is decelerated or stopped, the motor / generator MG2 converts kinetic energy generated during braking of the vehicle into electric energy (AC power). The inverter 24 converts the AC power generated by the motor / generator MG2 into DC power and outputs the DC power to the assembled battery 1. Thereby, the assembled battery 1 can store regenerative electric power.

  The assembled battery 1 may be connected to the booster circuit, and the booster circuit may be connected to the inverter 24. By using the booster circuit, the output voltage of the assembled battery 1 can be boosted, and the output voltage from the inverter 24 to the assembled battery 1 can be lowered.

  The engine 27 is a known internal combustion engine that outputs power by burning fuel such as a gasoline engine or a diesel engine.

  The charger 40 supplies power from the external power supply 43 to the assembled battery 1. Thereby, the assembled battery 1 can be charged. The charger 40 is connected to the assembled battery 1 via charging relays Rch1 and Rch2. When the charging relays Rch1 and Rch2 are on, power from the external power supply 43 can be supplied to the assembled battery 1. Switching control between on and off of the charging relays Rch1 and Rch2 is performed by the controller 30.

  The charger 40 is connected to an inlet 41, and a charging plug 42 is connected to the inlet 41. The charging plug 42 is a connection connector provided on the charging cable P extending from the external power source 43. By connecting the charging plug 42 to the inlet 41, external power from the external power supply 43 can be supplied to the assembled battery 1 via the charger 40.

  The external power source 43 is a power source provided outside the vehicle, and the external power source 43 is, for example, a commercial power source. When the external power supply 43 supplies AC power, the charger 40 includes an AC / DC converter (not shown), converts AC power from the external power supply 43 into DC power, and supplies DC power to the assembled battery 1. Charging the assembled battery 1 by supplying power from the external power source 43 to the assembled battery 1 is called external charging.

  The voltage monitoring unit 20 detects the voltage between the terminals of the assembled battery 1 and each single cell 10 and outputs the detection result to the controller 30. The current sensor 21 detects the charge / discharge current flowing through the assembled battery 1 and outputs the detection result to the controller 30. Regarding the current value detected by the current sensor 21, the discharge current can be a positive value and the charging current can be a negative value. The current sensor 21 can also detect a charging current supplied from an external power source via a charger 40 described later.

  The temperature sensor 22 detects the temperature (battery temperature) of the assembled battery 1 and outputs the detection result to the controller 30. Further, the temperature sensor 23 detects the temperature (intake air temperature) of cooling air (for example, air in the passenger compartment) for cooling the assembled battery 1 and outputs the detection result to the controller 30.

  Here, the cooling structure of the battery system will be described with reference to FIG. As shown in FIG. 2, the assembled battery 1 is accommodated in the case B, and the intake duct 3 and the exhaust duct 5 are connected to the case B. The intake duct 3 is connected to the case B via a blower (blower) 4. The cooling air supplied into the case B through the intake duct 3 exchanges heat with the assembled battery 1 and is discharged out of the case B from the exhaust duct 5. The blower 4 may be provided in the exhaust duct 5, or may be provided at an arbitrary position on the intake path between the intake duct 3 and the case B or on the exhaust path between the case B and the exhaust duct 5. it can.

  As shown in FIG. 2, the temperature sensor 22 is provided directly on a part of the assembled battery 1 and detects the temperature of the assembled battery 1, whereas the temperature sensor 23 is connected to the assembled battery 1 in the case B. It can be provided on the intake path for supplying cooling air and upstream of the assembled battery 1.

  At this time, energized components (for example, service plugs, positive and negative terminals of the assembled battery 1, system main relays SMR-B, SMR-G, and SMR-) are electrically connected to the assembled battery 1 in the case B. P, wire harnesses such as connection lines for connecting the inverters 24, fuses, and the like) are provided. These energized parts are cooled by the cooling air supplied from the intake duct 3 in the same manner as the assembled battery 1. And the temperature sensor 23 can be provided in the upstream of the assembled battery 1 like the example of FIG. 2, and can function as a temperature sensor which detects the ambient temperature of electricity supply components.

  The controller 30 is a control device that performs charge / discharge control of the assembled battery 1. The controller 30 has a memory 34 for storing various information, and the memory 34 also stores a program for operating the controller 30. The memory 34 can be provided to the controller 30 in a built-in type or an external type.

  The controller 30 can calculate the SOC of the assembled battery 1 based on the detected values of the voltage monitoring unit 20 and the current sensor 21, and can perform charge / discharge control of the assembled battery 1 based on the calculated SOC. The SOC of the assembled battery 1 can be calculated by a known method.

  The controller 30 determines the allowable input power (maximum value of power charged in the assembled battery 1) SW_in and allowable output power (maximum value of power discharged from the assembled battery 1) based on the temperature, SOC, etc. of the assembled battery 1. SW_out is calculated. The controller 30 limits the charge / discharge power of the assembled battery 1 so as not to exceed the allowable input power SW_in and the allowable output power SW_out. Thereby, the overdischarge and overcharge of the assembled battery 1 are prevented, and the assembled battery 1 is protected.

  On the other hand, when a current flows through the assembled battery 1, the current also flows through energized components that are electrically connected to the assembled battery 1 constituting the battery system, and Joule heat is generated in these energized components. Therefore, when the temperature of the energized component rises and exceeds the allowable temperature, the energized component may not function normally.

  Therefore, based on the current value of the assembled battery 1 detected during the operation time of the battery system, the evaluation value F related to the temperature state of these energized components is calculated, and based on the calculated evaluation value F, The allowable input power SW_in and the allowable output power SW_out calculated based on the temperature, the SOC, and the like are further limited to limit the input / output power to suppress the temperature rise of the energized components.

  As shown in FIG. 1, the controller 30 includes an evaluation value calculation unit 31 and a W_in / W_out changing unit 32.

  The evaluation value calculation unit 31 calculates an evaluation value F that is a value used for evaluating the temperature state (temperature rise) of the energized component. The evaluation value calculation unit 31 is an annealing coefficient that is set according to the current value I of the assembled battery 1, the evaluation value stored in the memory 34 (evaluation value calculated last time), and the temperature of the energized component. Based on K, the evaluation value F is calculated.

  The W_in / W_out changing unit 32 changes the allowable input power SW_in and the allowable output power SW_out that are set based on the temperature, SOC, and the like of the assembled battery 1 based on the evaluation value F calculated by the evaluation value calculating unit 31. The inverter 24 is controlled so as to limit the power of the battery pack 1 with the changed charge power upper limit value W_in and discharge power upper limit value W_out.

  Note that the controller 30 of this embodiment having the evaluation value calculation unit 31, the W_in / W_out change unit 32, and the atmospheric temperature state determination unit 33 described later can be configured by hardware mainly including a digital circuit and an analog circuit. . Alternatively, the CPU included in the controller 30 may be configured by software that reads and executes a predetermined program stored in the memory 34.

  FIG. 3 is a flowchart showing a process for controlling charging / discharging of the assembled battery 1 of the present embodiment.

  Next, the process shown in FIG. 3 is repeatedly performed at a preset time interval (cycle time), and is performed by the CPU included in the controller 30 executing a program stored in the memory 34.

  In step S <b> 101, when the ignition switch is turned on, the controller 30 activates the battery system and starts charge / discharge control of the assembled battery 1.

  In step S102, the controller 30 acquires the current value I of the discharge current or the charging current based on the output signal of the current sensor 21.

Here, the calculation method of the evaluation value F of the present embodiment will be described in detail. The controller 30 sets the evaluation value F (N) larger as the temperature of the energized component is higher so as to correlate with the temperature of the energized component. Further, the controller 30 calculates an evaluation value F (N) based on the detected current value I of the assembled battery 1 so as to correlate with the temperature of the energized component. For example, the evaluation value F (N) can be calculated by the following formula 1.
(Formula 1)

  In Equation 1, N indicates the number of times the evaluation value F is calculated. If the previously calculated evaluation value F (N-1) does not exist, the initial value of the evaluation value F can be used. The annealing coefficient K is a constant equal to or greater than 1, and is a value set according to a change in the temperature of the energized component.

  In step S103, the controller 30 calculates the smoothing coefficient K for calculating the evaluation value F. The calculation process of the annealing coefficient K will be described later.

  In step S104, the controller 30 calculates the evaluation value F based on the above-described equation 1 based on the annealing coefficient K and the current value I calculated in step S103.

  FIG. 4 is a diagram showing the relationship between the evaluation value F (N), the input / output limit value, and the temperature of the energized component in the present embodiment. As shown in FIG. 4, the evaluation value F (N) shown in Expression 1 increases as the charge / discharge current flows through the assembled battery 1. Until the evaluation value F (N) exceeds the threshold value Ftag2, the controller 30 performs input control with the allowable input power SW_in as an upper limit value, and input restriction is started when the evaluation value F (N) exceeds the threshold value Ftag2. The input control is performed with the charging power upper limit W_in (<SW_in) calculated by the W_in / W_out changing unit 32.

  Further, until the evaluation value F (N) exceeds the threshold value Ftag1, the controller 30 performs output control with the allowable output power SW_out as an upper limit value, and when the evaluation value F (N) exceeds the threshold value Ftag1, the output restriction is performed. The output control is performed with the discharge power upper limit value W_out (<SW_out) calculated by the W_in / W_out changing unit 32.

  In step S105, the controller 30 determines whether or not the evaluation value F (N) calculated in step S104 exceeds the threshold value Ftag2, and if so, the process proceeds to step S106, where the input restriction (allowed) is performed. The maximum value of the input power is reduced) and changed to W_in lower than SW_in.

  Subsequently, in step S107, when it is determined that the evaluation value F (N) calculated in step S104 does not exceed the threshold value Ftag2, or after starting input restriction, the controller 30 determines the evaluation value F (N ) Exceeds the threshold value Ftag1. If the evaluation value F (N) exceeds the threshold value Ftag1, the process proceeds to step S108, where output restriction (reducing the maximum value of the allowable output input power) is started and changed to W_out lower than SW_out.

  W_in and W_out in steps S106 and S108 can be calculated by, for example, feedback control using the evaluation value F (N) as a parameter. In this embodiment, the input / output restriction is controlled by different threshold values Ftag, and the input restriction start threshold value Ftag2 and the output restriction start threshold value Ftag1 are used. The threshold value Ftag can be calculated based on the allowable energization current value of the energized component as described in Patent Document 1.

（式２−２）

Each value of W_in / W_out when the evaluation value F exceeds the threshold value Ftag can be calculated as shown in the following equations 2-1 and 2-2.
(Formula 2-1)

(Formula 2-2)

  In Formula 2-1, W_in adds SW_in calculated based on the SOC of the battery pack 1 and the battery temperature to K_in × (F−Ftag2), which is a correction term based on feedback control using the evaluation value F as a parameter. This can be calculated. As described above, since the charging current is expressed by a negative value, the charging power can also be expressed by a negative value, and a correction term K_in × (F−Ftag2) that is a positive value is added to SW_in. Therefore, W_in is a larger value (a smaller value as an absolute value) than SW_in.

  In Expression 2-2, W_out subtracts K_out × (F−Ftag1), which is a correction term by feedback control using evaluation value F as a parameter, to SW_out calculated based on the SOC of the assembled battery 1 and the battery temperature. This can be calculated. As described above, since the discharge current is represented by a positive value, the discharge power can also be represented by a positive value, and the correction term K_out × (F−Ftag1), which is a positive value, is subtracted from SW_out. Therefore, W_out is smaller than SW_out.

  K_in and K_out are coefficients, are proportional control values of the correction term of the feedback control using the evaluation value F as a parameter, and are feedback gains for calculating W_in / W_out.

  In this way, the correction term K_in × (F−Ftag2) can be calculated as the input limit amount of the assembled battery 1, and the correction term K_out × (F−Ftag1) can be calculated as the output limit amount of the assembled battery 1. Then, by performing feedback control using the evaluation value F as a parameter, W_in / W_out lower than SW_in / SW_out is calculated, and input / output control of the assembled battery 1 is performed using W_in / W_out as an upper limit value. It can suppress that the temperature of components exceeds allowable temperature.

  On the other hand, the state in which the input / output power allowed when the evaluation value F exceeds the threshold value Ftag is limited to a low level is, for example, when the output of the assembled battery 1 for the vehicle request is insufficient, the power performance that meets the vehicle request Can not be demonstrated, drivability is reduced. Further, in the hybrid vehicle, the engine 27 is started to compensate for the shortage of output, so that fuel consumption is reduced. For this reason, it is preferable to avoid the intervention of the input / output restriction accompanying the suppression of the temperature rise of the energized parts as much as possible, and the timing of the intervention of the restriction can be delayed as much as possible even if the temperature rise of the energized parts is appropriately suppressed. preferable.

  Here, the evaluation value F (N) indicating the temperature state of the energized component is based on the square value of the current value I, but the temperature of the energized component is affected by the environmental temperature (the ambient temperature around the energized component). For this reason, the time during which the same current can be supplied (the time during which electricity can be supplied) differs between the allowable temperature (heat-resistant temperature) of the energized component between the low and high ambient temperatures. Therefore, in a state where the ambient temperature is low, the degree of temperature rise (rate of change in temperature of the energized component) is low even when the same current is passed, and it can be energized for a longer time than in a state where the ambient temperature is high.

  Therefore, in this embodiment, the ambient temperature of the energized component before the ignition switch of the vehicle is turned on is grasped, and the energized component that is charged / discharged if the energized component is below the predetermined ambient temperature for a long time. Therefore, the evaluation value F (N) is calculated to be smaller than when the temperature environment of the current-carrying component is not determined to be a low temperature state.

  FIG. 5 is a diagram showing a map of the smoothing coefficient K for calculating the evaluation value F (N) of the present embodiment, and shows the relationship between the current value according to the temperature environment of the energized component and its energizable time. FIG. In the present embodiment, as shown in FIG. 5, when the ambient temperature of the energized component before the ignition switch of the vehicle is turned on is a low temperature environment, the ambient temperature of the energized component is not a low temperature environment (is a high temperature environment). The maps for calculating the smoothing coefficient K are different depending on the case.

  As shown in FIG. 5, when the current value Ib flows through the energized component, the energizable time is tb in a high temperature environment, but in the low temperature environment, the degree of temperature rise is low, so the energizable time is low. It becomes ta longer than tb. The low temperature atmosphere temperature map indicated by the solid line is a map for calculating the annealing coefficient K_low based on the low temperature environment, and is defined based on the current value and the energization possible time at the current value.

  5 is a map for calculating the annealing coefficient K_high based on an environment other than the low temperature environment (high temperature environment), and shows a current value and energization at the current value. It is defined based on the possible time. These low temperature atmosphere temperature map and high temperature atmosphere temperature map can be obtained in advance by experiments or the like by changing the environmental temperature.

  By distinguishing between the case where the ambient temperature of the current-carrying part before the ignition switch of the vehicle is turned on is a low temperature environment and the case where it is not, the evaluation value F (N) is calculated to be small. As shown in FIG. 4, the timing at which the input / output restriction intervenes can be delayed. In the example of FIG. 4, when the evaluation value F (N) is calculated using the annealing coefficient K_low calculated by the low temperature ambient temperature map of FIG. 5 in the solid line, the evaluation value F (N) and the upper limit of the input / output power The evaluation value F (N) and the input / output when the evaluation value F (N) is calculated using the annealing coefficient K_high calculated by the high temperature ambient temperature map of FIG. The change of the upper limit value of electric power is shown.

  In the high temperature environment, the evaluation value F (N) exceeds the threshold value Ftag2 at time t1, but in the low temperature environment, it can be energized for a longer time than in the high temperature environment, so that the evaluation value F (N) is larger than the annealing coefficient K_high. By applying the set annealing coefficient K_low, the rate of increase of the evaluation value F (N) becomes low. For this reason, since the evaluation value F (N) exceeds the threshold value Ftag2 at time t3, which is longer in time than time t1, the timing at which the input restriction intervenes can be delayed. Further, in the high temperature environment, the evaluation value F (N) exceeds the threshold value Ftag1 at time t2. However, in the low temperature environment, the evaluation is performed at time t4 that is longer in time than time t2 by similarly applying the coefficient K_low. Since the value F (N) exceeds the threshold value Ftag1, the timing at which the output restriction intervenes can be delayed.

  As described above, in this embodiment, when it is determined that the energized component is in the low temperature environment, the annealing coefficient K for calculating the evaluation value F (N) is higher than that in the high temperature environment (when it is not the low temperature environment). Is set to a large value, and the evaluation value F (N) is calculated according to the temperature environment of the energized parts. Note that the low temperature ambient temperature map and the high temperature ambient temperature map shown in FIG. 5 are set such that the values of the annealing coefficients K_low and K_high become smaller as the flowing current value increases, and for the same current value. The margin coefficient K_low is set to be larger than the annealing coefficient K_high.

  In this embodiment, as a method for determining that the temperature environment of the energized parts to be charged and discharged is in a low temperature state, the ambient temperature of the energized parts before the ignition switch of the vehicle is turned on is grasped, and the ignition of the vehicle is determined. The temperature of the current-carrying part when charging / discharging after the ignition switch of the vehicle is turned on when the current-carrying part has continued for a predetermined time or longer in a state of a predetermined ambient temperature or lower before the switch is turned on. Judge that the environment is cold.

  FIG. 6 is a flowchart showing a low-temperature atmosphere determination process for the current-carrying component when the ignition switch of the vehicle of this embodiment is off. The controller 30 further includes a low temperature atmosphere state determination unit 33.

  The low-temperature atmosphere state determination unit 33 includes a timer function that measures an elapsed time in a state where the ignition switch of the vehicle is turned off, and measures an elapsed time after the ignition switch of the vehicle is turned off in step S301.

  At this time, external charging can be performed in a state where the ignition switch of the vehicle is turned off. Therefore, the low-temperature atmosphere state determination unit 33 determines whether or not external charging is performed while the ignition switch is off (S302). If external charging is performed, the process proceeds to step S303.

  In step S303, it is determined whether or not the charging current is smaller than a predetermined current value (low current determination value). This is because when the charging current by external charging is large, the amount of heat generated by the assembled battery 1 increases, and the temperature of the assembled battery 1 rises, so that the ambient temperature of the energized parts increases. A low current determination value that has a small charging current and does not increase the ambient temperature of the energized component with respect to the temperature rise of the assembled battery 1 is obtained in advance by experiments or the like, and in step S303, the charging current for external charging has a low low current determination value. By determining whether or not, the state in which the ambient temperature of the current-carrying parts becomes high due to external charging is excluded in advance.

  The low-temperature atmosphere state determination unit 33 does not perform external charging (NO in S302), or performs external charging with a charging current smaller than a predetermined current value even when external charging is performed (S303). In step S304, it is determined whether the energized component is in a state of a predetermined low temperature ambient temperature or less.

  Whether or not the energized component is in a state of a predetermined low temperature ambient temperature or less can be determined using the battery temperature T1 and the intake air temperature T2 of the assembled battery 1. The low temperature atmosphere state determination unit 33 is energized when the battery temperature T1 of the assembled battery 1 is lower than a predetermined temperature (low battery temperature threshold) and the intake air temperature T2 is lower than a predetermined temperature (low intake air temperature determination value). It is determined that the component is in a state of a predetermined low temperature ambient temperature or less, and the process proceeds to step S305 to increment the low temperature atmosphere continuation counter.

  The low temperature atmosphere continuation counter indicates a duration (low temperature duration) during which the energized component is exposed in a state of a predetermined low temperature atmosphere temperature or lower. For example, when the process shown in FIG. 6 is performed at a cycle time every other hour, the low temperature atmosphere continuation counter is incremented as the number of times that the energized component is determined to be in a state of a predetermined low temperature atmosphere temperature or less. By multiplying the counted counter value by one hour which is the cycle time, the low temperature continuation time of the energized component after the ignition switch of the vehicle is turned off can be calculated.

  Note that the elapsed time from when it is determined that the energized component is initially exposed to a temperature lower than or equal to the predetermined low temperature temperature by the timer timing is calculated, and the low temperature duration of the energized component is calculated. May be.

  On the other hand, when the charging current of external charging is larger than a predetermined current value (low current determination value) in step S303, or when it is determined in step S304 that the energized component is not in a state of a predetermined low temperature ambient temperature or not, the process proceeds to step S306. Advance and reset (initialize) the low-temperature atmosphere continuation counter. In this embodiment, when the energized component is exposed to a state of a predetermined low temperature ambient temperature or lower for a long time to some extent, it is determined that the energized component is in a low temperature environment. While preventing overheating of parts, delay the timing of I / O restriction intervention to reduce fuel consumption.

  Therefore, in step S306, even if it is determined in the previous low-temperature atmosphere determination process that the energized component is in a state equal to or lower than the predetermined low-temperature atmosphere temperature, it is determined that the current energized component is not in a state equal to or lower than the predetermined low-temperature atmosphere temperature. If it is, the low temperature atmosphere continuation counter is reset, and the low temperature atmosphere continuation counter is incremented again from 0 in the next low temperature atmosphere determination process.

  FIG. 7 is a flowchart showing detailed processing of step S103 of FIG.

  In the calculation process of the evaluation value F (N) after the ignition switch of the vehicle is turned on, the controller 30 determines that the low temperature continuation time before the ignition switch of the vehicle is turned on is longer than a predetermined time (elapsed time determination value C1). It is determined whether or not it is larger (S1031). When the low continuation time before the ignition switch of the vehicle is turned on is longer than the predetermined time, the controller 30 proceeds to step S1032, and after the vehicle switch shown in FIG. 1 is started after the ignition switch of the vehicle is turned on It is determined whether or not the time is smaller than a predetermined time (elapsed time determination value C2).

  The controller 30 determines that the low duration before the vehicle ignition switch is turned on is greater than the elapsed time determination value C1, and the elapsed time after the vehicle ignition switch is turned on and the battery system is activated. When the value is smaller than the determination value C2, the smoothing coefficient K_low is calculated based on the current value I acquired in step S102 using the low temperature atmosphere temperature map shown in FIG. 5 (S1033).

  On the other hand, when the low duration before the ignition switch of the vehicle is turned on is smaller than the elapsed time determination value C1, or the elapsed time after the battery system is started by turning on the ignition switch of the vehicle, the controller 30 When the elapsed time determination value C2 is larger, the smoothing coefficient K_high is calculated based on the current value I acquired in step S102 using the high-temperature atmosphere temperature map shown in FIG. 5 (S1034).

  In step S104, the controller 30 calculates the evaluation value F (N) based on Equation 1 described above based on the annealing coefficient K_low or K_high calculated in step S103 and the current value I.

  In the present embodiment, during a certain period after the ignition switch of the vehicle is turned on and the battery system is activated, the evaluation value F (N) is calculated by applying the smoothing coefficient K_low, but the battery system is activated. After a certain period of time has elapsed, an evaluation value F (N) calculation process using the coefficient K_high is performed. This is because the temperature rise of the assembled battery 1 due to charging and discharging and the temperature rise due to energization of the energized parts are taken into account, and priority is given to overheating protection of the energized parts due to the increase in the ambient temperature.

  Therefore, the controller 30 measures time from when the ignition switch of the vehicle is turned on and the battery system is activated, and calculates an annealing coefficient K_low based on the evaluation value F (N) as shown in FIG. When the input / output control is performed, if the elapsed time after the battery system is started becomes larger than the elapsed time determination value C2 in the next processing cycle, the controller 30 turns on the ignition switch of the vehicle. Even if it is determined that the current-carrying part was in a low-temperature environment before switching to the high-temperature atmosphere temperature map shown in FIG. 5, the smoothing coefficient K_high is calculated thereafter to calculate the evaluation value F (N).

  According to the present embodiment, the current-carrying component is in a state below the predetermined atmospheric temperature based on the battery temperature and the intake air temperature of the assembled battery 1 after the ignition switch of the vehicle is turned off until the ignition switch is turned on. Whether or not the ignition switch of the vehicle is turned on, and the duration time during which the energized component is below the ambient temperature is counted. Then, when the duration of the temperature below the ambient temperature before the ignition switch of the vehicle is turned on is longer than a predetermined time, it is determined that the energized component is in a low temperature environment and the vehicle ignition switch is turned on. The evaluation value F (N) is calculated to be smaller than the case where the temperature environment is not low until a certain time.

  For this reason, the evaluation value F (N) until a certain time after the ignition switch of the vehicle is turned on is calculated to be small according to the low temperature environment where the energized time for the same current becomes long, and the evaluation value F ( The time until N) exceeds the threshold value Ftag becomes longer, and the timing at which the input / output restriction associated with the suppression of the temperature rise of the energized components can be delayed. Accordingly, it is possible to suppress drivability deterioration and fuel consumption deterioration.

  Further, the vehicle equipped with the battery system shown in FIG. 1 selects a drive supply source according to the driving state, and travels the vehicle using the driving force from one or both of the engine 27 and the motor / generator MG2. It can be carried out. For example, without using the driving force from the engine 27 (with the engine 27 stopped), the hybrid vehicle can travel (EV traveling) using only the motor / generator MG2 as a driving source.

  In EV traveling after the ignition switch of the vehicle is turned on, it is determined that the temperature environment of the energized component due to charging / discharging during EV traveling is a low temperature state until a certain period, and the temperature environment of the energized component is not determined to be the low temperature state. Since the evaluation value F (N) is calculated to be smaller than the time, the timing at which the input / output restriction accompanying the suppression of the temperature rise of the energized parts can be delayed, and the EV travel distance without driving the engine 27 Can be lengthened.

  Further, even if external charging is performed before the ignition switch of the vehicle is turned on, if it is determined that the current-carrying component is in a low temperature environment, the engine 27 is not driven in the same manner during EV traveling after external charging. The distance that can be traveled by EV can be increased.

1: assembled battery 10: single cell 20: voltage monitoring unit 21: current sensor 22, 23: temperature sensor 24: inverter 25: drive wheel 26: power split mechanism 27: engine 30: controller 31: evaluation value calculation unit 32: W_in / W_out changing unit 33: ambient temperature state determination unit 34: memory 40: charger 41: inlet 42: charging plug 43: external power supply MG1, MG2: motor generator

Claims (1)

A power storage system including a power storage device that supplies electric power to a vehicle driving motor,
A current sensor for detecting a charge / discharge current of the power storage device;
A first temperature sensor for detecting a temperature of the power storage device;
A second temperature sensor for detecting an intake temperature of temperature adjusting air supplied to the power storage device;
A controller that performs charge / discharge control according to the temperature of the energized component electrically connected to the power storage device,
The controller is
An evaluation value calculation unit that calculates an evaluation value for evaluating the temperature state of the energized component based on a current value detected during charging and discharging of the power storage device;
When the evaluation value exceeds a threshold, a change unit that limits the upper limit value of the discharge power or charge power of the power storage device;
Whether the current-carrying component is in a state of a predetermined atmospheric temperature or less based on the temperature of the power storage device and the intake air temperature from when the ignition switch of the vehicle is turned off until the ignition switch is turned on And an ambient temperature state determination unit that counts a duration time during which the current-carrying component is in the state below the ambient temperature until the ignition switch of the vehicle is turned on, and
When the duration before the ignition switch of the vehicle is turned on is equal to or longer than a predetermined time, the evaluation value calculation unit is configured to continue the duration until a predetermined time after the ignition switch of the vehicle is turned on. The power storage system is characterized in that the evaluation value is calculated to be smaller than when the time is shorter than the predetermined time or when the energized component is not in the ambient temperature or lower.

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