JP6657879B2 - Battery control system, hybrid vehicle, and battery control method - Google Patents

Description

  The present invention relates to a battery control system, a hybrid vehicle, and a battery control method, and more particularly, to a motor generator that is a power source for driving a vehicle, a battery connected to the motor generator via an inverter, and a control device. , A hybrid vehicle and a battery control method.

  2. Description of the Related Art In recent years, a hybrid vehicle (hereinafter, referred to as an “HEV”) including a hybrid system having an engine and a motor generator that are combined and controlled in accordance with the driving state of the vehicle has attracted attention from the viewpoint of improving fuel efficiency and environmental measures. I have. In the HEV, a driving force is assisted by a motor generator when the vehicle is accelerating or starting, while a regenerative power is generated by the motor generator during inertial running or starting (for example, see Patent Document 1).

  On the other hand, a motor generator is used as a power source for running the vehicle, such as an HEV or an electric automatic vehicle (hereinafter referred to as “EV”) that uses only a motor generator without a built-in engine as a power source for running the vehicle. In a mounted vehicle, a battery (such as a lithium ion battery or a nickel hydride battery) for running the vehicle is connected to the motor generator via an inverter. Then, charging and discharging between the motor generator and the battery are repeated based on the running state of the vehicle.

  Here, a vehicle running battery mounted on an HEV or EV has a plurality of cells mounted therein, and the battery can be charged and discharged by an electrochemical reaction of each cell. When charging / discharging of the battery is performed based on the running state of the vehicle, each cell (in particular, an electrode) inside the battery generates heat. As the amount of charge / discharge current to the battery increases, the amount of heat generated in each cell inside the battery increases. However, if the amount of heat generated in each cell becomes excessive, each cell may be thermally damaged and the battery may be abnormally deteriorated. There is.

  Therefore, in the related art, a limit value is set based on the state of charge (SOC) and surface temperature of the battery, and the amount of heat generated by each cell is suppressed by setting the charge / discharge current to the battery to be equal to or less than the limit value. As a result, abnormal deterioration of the battery was suppressed.

  However, since it takes time for the heat generation of each cell inside the battery to be transmitted to the surface of the battery, even if the battery surface temperature has not yet become high, each cell generates heat and becomes hot. In such a case, if the amount of charge / discharge current to the battery is controlled with respect to a limit value set based on the surface temperature of the battery, as in the conventional technology, the temperature of the cell becomes high. On the other hand, there is a possibility that a charge / discharge current amount larger than the allowable amount flows, and there is a possibility that the cells are thermally damaged and the battery is abnormally deteriorated.

  In connection with this problem, the temperature load factor rise (heat generation) is estimated by integrating the battery current value with time, and the estimated temperature load factor rise is added based on the temperature load factor initial value, The estimated value of the temperature load factor is calculated by subtracting the decrease in the temperature load factor (the amount of heat radiation), and the smaller of the estimated value of the temperature load factor and the predetermined maximum value of the temperature load factor is used as the estimated value of the temperature load factor. The temperature load factor margin is calculated by subtracting the temperature load factor estimation value from the maximum value of the temperature load factor, and each element constituting the power supply system is calculated according to the ratio of the temperature load factor margin to the maximum temperature load factor. A vehicle control system that performs limiter processing of an allowable current value using a value set so as not to exceed the short-time rated value as an allowable current value of a main battery has been proposed (for example, see Patent Document 2).

  However, in this vehicle control system, a complicated calculation is performed until the allowable current value of the main battery is calculated. If the initial value of the temperature load factor is not accurately obtained, the error is subtracted, and the output of the battery is also reduced. There is a problem that it takes time to limit the power.

JP 2002-238105 A JP 2014-135840 A

  SUMMARY OF THE INVENTION An object of the present invention is to control a battery capable of quickly and surely suppressing the heat generation of each cell inside a battery, suppressing heat loss of each cell, and reliably suppressing abnormal deterioration of the battery. An object of the present invention is to provide a control method for a system, a hybrid vehicle, and a battery.

A battery control system according to the present invention that achieves the above object includes a motor generator that is a power source for driving a vehicle, a battery connected to the motor generator via an inverter, and a control device. In the control system, the control device calculates a charge / discharge current threshold based on a charge state of the battery and a surface temperature of the battery for each preset control time, and controls the battery via the inverter. A charging / discharging current effective value, which is a current value charged and discharged, is input, and an effective current moving average value obtained by moving average of the plurality of charging / discharging current effective values input during a predetermined moving average time is calculated. and, wherein the charge and discharge current effective value is equal to or in the charge and discharge current equal to or larger than the threshold, the charge and discharge current effective value before If it is determined that the charge and discharge current threshold above the decreased by decrease in advance set the charge and discharge current effective value, if the charging and discharging current effective value is determined to be less than the discharge current threshold value, the effective It is determined whether or not the current moving average value is equal to or greater than a preset effective current moving average threshold value, and when it is determined that the effective current moving average value is equal to or greater than the effective current moving average threshold value, the charge / discharge current effective value is determined. Is controlled to decrease by the decrease amount .

In the above battery control system, the moving average time is set to a plurality of times including at least a short time set in advance and a long time set to a time longer than the short time, and A threshold value is set for each of the plurality of moving average times, and when the control device determines that the charge / discharge current effective value is less than the charge / discharge current threshold value, for each of the moving average times, the effective current moving average value Is determined to be not less than the effective current moving average threshold value.

  Further, in the above battery control system, the control device sets the effective current moving average threshold value to a specification value of the battery, and a specification value of a harness for connecting the battery to the motor generator via the inverter. It is configured to be set based on

  In addition, the hybrid vehicle of the present invention that achieves the above object has the motor generator configured as a motor generator connected to an output shaft that transmits power of an engine, and a hybrid system having the motor generator and the battery described above. It is configured with a control system.

Further, a battery control method of the present invention for achieving the above object is a battery control method comprising: a motor generator serving as a power source for driving a vehicle; and a battery connected to the motor generator via an inverter. Calculating a charge / discharge current threshold based on a state of charge of the battery and a surface temperature of the battery for each preset control time, and a current value for charging / discharging the battery via the inverter. The effective value of the charging / discharging current is inputted, and the effective value of the charging / discharging current including the inputted effective value of the charging / discharging current is input, and the moving average of the plurality of effective values of the charging / discharging current for each control time is performed during a moving average time set in advance. a first step of calculating an effective current moving average value, the charging and discharging current effective value whether a said charging and discharging current threshold above A second step of determining the effective current movement, wherein the effective current movement average value is set in advance when the effective value of the charge / discharge current is determined to be less than the threshold value of the charge / discharge current in the second step. A third step of determining whether or not the average threshold value or more, and if the charge and discharge current effective value is determined to be equal to or more than the charge and discharge current threshold in the second step, or, in the third step A fourth step of reducing the charge / discharge current effective value by a preset decrease when it is determined that the effective current moving average value is equal to or greater than the effective current moving average threshold value. Is a method.

Further, in the above-described battery control method, the moving average time is set to a plurality of times including at least a short time set in advance and a long time set to a time longer than the short time, and A threshold value is set for each of the plurality of moving average times, and when it is determined that the effective value of the charging / discharging current is less than the charging / discharging current threshold value, the effective current moving average value is determined for each of the moving average times. This is a method characterized in that it is determined whether or not the average threshold value is exceeded.

  According to the battery control system, the hybrid vehicle, and the battery control method of the present invention, in addition to monitoring the charge / discharge current threshold based on the surface temperature of the battery, in order to monitor the amount of accumulated heat inside the cell, An effective current moving average value, which is a moving average value of the effective value of the charge / discharge current for the battery, is calculated every moment, and when the effective current moving average value is equal to or greater than a preset effective current moving average threshold value, Control is performed to reduce the effective value of the charge / discharge current, assuming that the heat value of each internal cell approaches the amount at which the heat loss of each cell is concerned, so that the increase in the heat value of each cell inside the battery is reliably suppressed. Thus, heat loss of each cell can be suppressed, and abnormal deterioration of the battery can be reliably suppressed.

  In addition, since the moving average value of the effective value of the charge / discharge current calculated every moment is used for control, the responsiveness can be significantly increased as compared with the case where the integrated value is used, and a short time corresponding to the specification of the battery can be achieved. It is possible to flexibly cope with a corresponding current limit value and a long-time current limit value. Further, since the calculation method in the control is relatively simple, the amount of heat generated in each cell inside the battery can be quickly suppressed without complicating the control.

  In addition, a plurality of combinations of the moving average period for calculating the effective current moving average value and the effective current moving average threshold value for the moving average period may be set, or only moving averages having different moving average periods may be performed in parallel. Therefore, control for a plurality of standards, such as for a moving average time of 10 s or 60 s, can be performed in parallel without complicating control and without impairing responsiveness.

  In addition, since the effective current moving average threshold value for the battery is set based on both the battery specification value (allowable storage amount, etc.) and the harness specification value (wire diameter, etc.) with reference to the experimental results, etc. The accuracy of estimating the calorific value of each internal cell can be improved, and the heat loss of the harness can be suppressed.

  Therefore, by appropriately setting the upper limit of the calorific value of the battery in the form of an effective current moving average threshold value, it is possible to prevent the battery from being thermally degraded, and to control the battery life without affecting the vehicle performance. Can be improved. Therefore, by incorporating control measures to prevent thermal degradation on the battery side, even in the HEV and EV markets, even if the battery is used in a state far out of the expectation, the risk of thermal degradation occurring can be reduced, Variations in battery deterioration can be reduced.

1 is a configuration diagram of a hybrid vehicle including a battery control system according to an embodiment of the present invention. 1 is a configuration diagram of an electric motor vehicle including a battery control system according to an embodiment of the present invention. It is a figure showing the control flow of the control method of the battery which consists of an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a hybrid vehicle provided with a battery control system according to an embodiment of the present invention. FIG. 2 shows an electric motor vehicle equipped with a battery control system according to an embodiment of the present invention. Note that the feature of the present invention is a battery control system. As long as the vehicle has a motor generator for running the vehicle, it does not depend on the type of vehicle having the battery control system. Only the configuration of FIG. 2 will be described, and description of the configuration of FIG. 2 will be omitted.

  This hybrid vehicle (hereinafter referred to as “HEV”) is a vehicle including not only ordinary passenger cars but also buses and trucks, and has an engine 10 and a motor generator 31 that are combined and controlled according to the driving state of the vehicle. The hybrid system 30 is provided.

  In the engine 10, the crankshaft 13 is driven to rotate by heat energy generated by combustion of fuel in a plurality (four in this example) of cylinders 12 formed in the engine body 11. As the engine 10, a diesel engine or a gasoline engine is used. The rotational power of the crankshaft 13 is transmitted to the transmission 20 through a clutch 14 (for example, a wet multi-plate clutch) connected to one end of the crankshaft 13.

  The rotational power shifted by the transmission 20 is transmitted to a differential 23 through a propeller shaft 22 and distributed as a driving force to a pair of driving wheels 24, respectively.

  The hybrid system 30 includes a motor generator 31, and an inverter 35, a high-voltage battery 32, a DC / DC converter 33, and a low-voltage battery 34 that are electrically connected to the motor generator 31 in order.

  As the high voltage battery 32, a lithium ion battery, a nickel hydride battery or the like is preferably exemplified. A lead battery is used as the low-voltage battery 34.

  The DC / DC converter 33 has a function of controlling the direction of charging and discharging between the high-voltage battery 32 and the low-voltage battery 34 and the output voltage. The low-voltage battery 34 supplies electric power to various vehicle electrical components 36.

  Various parameters in the hybrid system 30, such as a current value, a voltage value, and an SOC value, are detected by a BMS (battery management system) 39.

  The motor generator 31 is an endless loop wound between the first pulley 15 attached to the rotating shaft 37 and the second pulley 16 attached to the other end of the crankshaft 13 which is the output shaft of the engine body 11. The power is transmitted to and from the engine 10 through the belt-shaped member 17 of FIG. Note that, instead of the two pulleys 15 and 16 and the belt-shaped member 17, power can be transmitted using a gear box or the like. The output shaft of the engine main body 11 connected to the motor generator 31 is not limited to the crankshaft 13, but may be, for example, a transmission shaft between the engine main body 11 and the transmission 20 or a propeller shaft 22.

  The motor generator 31 may have a function of performing cranking instead of a starter motor (not shown) for starting the engine body 11.

  The engine 10 and the hybrid system 30 are controlled by the control device 80. Specifically, at the time of starting or accelerating the HEV, the hybrid system 30 assists at least a part of the driving force by the motor generator 31 supplied with power from the high-voltage battery 32, while at the time of inertial running or braking. Performs regenerative power generation by the motor generator 31, converts surplus kinetic energy into electric power, and charges the high-voltage battery 32.

  The battery control system of the present invention includes a motor generator 31 that is a power source for running a vehicle, a high-voltage battery (battery) 32 connected to the motor generator 31 via an inverter 35, and a control device 80. It is a system equipped with.

  Then, the control device 80 calculates the charge / discharge current threshold Ic based on the state of charge of the high-voltage battery 32 and the surface temperature of the high-voltage battery 32, and charges / discharges the high-voltage battery 32 via the inverter 35. The control is performed such that the effective value I of the charging / discharging current, which is the current value of the charging / discharging current, is equal to or less than the charging / discharging current threshold Ic. This charge / discharge current effective value I is detected by the BMS 39. Further, the charging / discharging current threshold value Ic is set to an optimum value obtained in advance by an experiment or the like.

  In the present invention, the control device 80 further calculates the effective current moving average value Im, which is a moving average value of the charge / discharge current effective value I during a predetermined moving average time tm, and calculates the calculated effective current. When the moving average value Im becomes equal to or greater than a preset effective current moving average threshold value Imc, control is performed to decrease the charge / discharge current effective value I. The moving average time tm is a value that is set in units of seconds (for example, 10 seconds, 60 seconds) with reference to experimental results and the like based on specification values such as the allowable storage amount of the high-voltage battery 32.

  In the present invention, the charge / discharge current effective value I is controlled to be equal to or less than the charge / discharge current threshold value Ic, and when the effective current moving average value Im is equal to or greater than the effective current moving average threshold value Imc, the charge / discharge current effective value I is set to The control to decrease the value is always performed every preset control time, that is, every moment as long as the motor generator 31 is in the operating state.

  Further, the control device 80 sets the effective current moving average threshold value Imc to the specification value of the high-voltage battery 32 and the specification value such as the wire diameter of a harness for connecting the high-voltage battery 32 to the motor generator 31 via the inverter 35. Is set based on the experimental results and the like based on. The effective current moving average threshold value Imc is a fixed value set according to the moving average time tm (for example, 10 seconds, 60 seconds). It is preferable to use a plurality of combinations of the moving average time tm and the effective current moving average threshold value Imc. This makes it possible to perform monitoring for a short time and monitoring for a long time at the same time. Can be suppressed.

  In the above description, the control device 80 calculates or sets the charging / discharging current threshold value Ic, the effective current moving average value Im, and the effective current moving average threshold value Imc. It may be. In the above description, the control device 80 controls the charge / discharge current effective value I to be equal to or less than the charge / discharge current threshold value Ic, and furthermore, sets the effective current moving average value Im to be equal to or greater than the effective current moving average threshold value Imc. When this happens, the control for decreasing the charge / discharge current effective value I is performed, but these controls may also be performed by the BMS 39.

  Next, a battery control method of the present invention based on the above-described battery control system will be described with reference to the control flow of FIG. The control flow of FIG. 3 is called from the advanced control flow when the motor generator 31 is in the operating state, and is repeatedly executed. When the motor generator 31 is switched from the operating state to the stopped state, the control flow returns to the advanced control flow. As shown.

  The control flow of FIG. 3 will be described. When the motor generator 31 is in the operating state and the control flow of FIG. 3 starts, in step S10, the charge / discharge current threshold Ic is calculated based on the charge state of the high-voltage battery 32 and the surface temperature of the high-voltage battery 32. In addition, an effective current moving average value Im is calculated or input. At the same time, the charging / discharging current effective value I is input, and the charging / discharging current effective value I is calculated as an effective current moving average value Im during a predetermined moving average time tm.

  In the next step S20, it is determined whether or not the effective value I of the charge / discharge current is equal to or greater than the charge / discharge current threshold value Ic. If the charge / discharge current effective value I is equal to or greater than the charge / discharge current threshold value Ic (YES) in step S20, the process proceeds to step S40, where the charge / discharge current effective value I is set in advance. It returns to the return after decreasing by the amount of the decrease, and returns to the advanced control flow. If the charge / discharge current effective value I is smaller than the charge / discharge current threshold value Ic (NO) in step S20, the process proceeds to step S30.

  In this step S30, it is determined whether or not the effective current moving average value Im is equal to or greater than the effective current moving average threshold value Imc. If the effective current moving average value Im is equal to or larger than the effective current moving average threshold value Imc (YES), the process proceeds to step S40, where the charge / discharge current effective value I is reduced by a preset decrease. To return and return to the advanced control flow. If the effective current moving average value Im is less than the effective current moving average threshold value Imc in step S30 (NO), the process directly returns to the advanced control flow. Then, as long as the motor generator 31 is in the operating state, the control flow of FIG. 3 is repeatedly performed.

  As described above, the battery control method of the present invention based on the above-described battery control system provides a motor generator 31 which is a power source for driving a vehicle and a motor generator 31 connected to the motor generator 31 via the inverter 35. And controlling the charge / discharge current threshold Ic based on the state of charge of the high-voltage battery 32 and the surface temperature of the high-voltage battery 32, and controlling the high-voltage battery 32 with an inverter. The charging / discharging current effective value I, which is a current value charged / discharged via the control terminal 35, is controlled to be equal to or less than the charging / discharging current threshold value Ic, and the charging / discharging current effective value I is set for a predetermined moving average time tm. An integrated effective current moving average value Im is calculated, and the calculated effective current moving average value Im is set to a predetermined effective value. When a flow moving average threshold Imc above is a method and performing control to reduce the charge and discharge current effective value I.

  Further, in the above battery control method, a plurality of combinations of the moving average period tm for calculating the effective current moving average threshold Im and the effective current moving average threshold Imc for the moving average period tm are set. How to

  In the battery control method described above, the effective current moving average threshold value Imc is set to the specification value of the high-voltage battery 32 and the specification value of the harness for connecting the high-voltage battery 32 to the motor generator 31 via the inverter 35. The method is characterized in that the setting is performed on the basis of the above.

  According to the battery control system, the hybrid vehicle, and the battery control method of the present invention, not only the charge / discharge current threshold Ic based on the surface temperature of the high-voltage battery 32 is monitored, but also the amount of heat generated and accumulated inside the cell. For this purpose, an effective current moving average value Im, which is a moving average value of the charge / discharge current effective value I for the high-voltage battery 32, is calculated every moment, and the effective current moving average value Im is set to a preset effective current moving average value. If the value is equal to or greater than the threshold value Imc, control is performed to reduce the effective value I of the charge / discharge current, assuming that the heat value of each cell inside the high-voltage battery 32 approaches an amount at which heat loss of each cell is concerned. In addition, it is possible to reliably suppress an increase in the amount of heat generated in each cell inside the high-voltage battery 32, to suppress heat loss in each cell, and to prevent abnormalities in the high-voltage battery 32. It is possible to reliably suppress the reduction.

  In addition, since the moving average value of the charge / discharge current effective value I calculated every moment is used for the control, the responsiveness can be remarkably increased as compared with the case where the integrated value is used. It is also possible to flexibly cope with a corresponding short-time current limit value and a long-time current limit value. Further, since the calculation method in the control is relatively simple, the heat generation of each cell inside the high-voltage battery 32 can be quickly suppressed without complicating the control.

  In addition, a plurality of combinations of the moving average period tm for calculating the effective current moving average value Im and the effective current moving average threshold value Imc for the moving average period tm may be set, or the moving average period tm may be different in parallel. Since it is only necessary to perform averaging, it is not necessary to complicate the control with respect to a plurality of standards, such as, for example, a response to a moving average time tm of 10 s or 60 s. Can be done.

  In addition, the effective current moving average threshold value Imc for the high-voltage battery 32 is determined based on both the specification value of the high-voltage battery (such as the allowable storage amount) and the specification value of the harness (such as the wire diameter) by referring to experimental results. Therefore, the accuracy of estimating the amount of heat generated by each cell inside the high-voltage battery 32 can be improved, and the heat loss of the harness can be suppressed.

10 engine 11 engine body 30 hybrid system 31 motor generator 32 high voltage battery (battery)
35 Inverter 80 Control device I Charge / discharge current effective value Ic Charge / discharge current threshold Im Effective current moving average value Imc Effective current moving average threshold tm Moving average time

Claims (6)

In a battery control system including a motor generator that is a power source for driving the vehicle, a battery connected to the motor generator via an inverter, and a control device,
The control device,
For each preset control time, a charge / discharge current threshold is calculated based on the state of charge of the battery and the surface temperature of the battery, and a current value for charging / discharging the battery via the inverter. The effective value of the charge / discharge current is input, and an effective current moving average value obtained by moving average of the plurality of effective values of the charge / discharge current input during a predetermined moving average time is calculated.
Determine whether the charge / discharge current effective value is not less than the charge / discharge current threshold ,
When it is determined that the charge / discharge current effective value is equal to or greater than the charge / discharge current threshold, the charge / discharge current effective value is reduced by a preset reduction amount,
When it is determined that the charge / discharge current effective value is less than the charge / discharge current threshold, it is determined whether the effective current moving average value is equal to or greater than a preset effective current moving average threshold value ,
A battery control system configured to perform control to reduce the charge / discharge current effective value by the decrease when the effective current moving average value is equal to or greater than the effective current moving average threshold value . The moving average time is set to a plurality of times including at least a short time set in advance and a long time set to a time longer than the short time, and the effective current average threshold is set for each of the plurality of moving average times. Is set,
The control device,
When it is determined that the charge / discharge current effective value is less than the charge / discharge current threshold value, it is determined whether or not the effective current moving average value is equal to or more than the effective current moving average threshold value for each moving average time. 2. The battery control system according to claim 1. The control device,
The configuration in which the effective current moving average threshold value is set based on a specification value of the battery and a specification value of a harness for connecting the battery to the motor generator via the inverter. Or the control system of the battery of Claim 2.   The motor generator is configured as a motor generator connected to an output shaft for transmitting the power of an engine, and a hybrid system including the motor generator and the battery control system according to any one of claims 1 to 3 are provided. Hybrid vehicle. A battery control method comprising: a motor generator serving as a power source for driving a vehicle; and a battery connected to the motor generator via an inverter,
A charge / discharge current threshold is calculated based on the state of charge of the battery and the surface temperature of the battery for each preset control time, and a current value that is charged / discharged to / from the battery via the inverter. A charging / discharging current effective value is inputted, the effective current including the inputted charging / discharging current effective value, and moving average of a plurality of the charging / discharging current effective values for each control time during a predetermined moving average time. A first step of calculating a moving average,
A second step of determining whether the charge / discharge current effective value is equal to or greater than the charge / discharge current threshold ,
In the second step, performed when it is determined that the charge / discharge current effective value is less than the charge / discharge current threshold, whether or not the effective current moving average is equal to or greater than a preset effective current moving average threshold A third step of determining
If the charge / discharge current effective value is determined to be equal to or greater than the charge / discharge current threshold value in the second step, or if the effective current moving average value is equal to or greater than the effective current moving average threshold value in the third step. And a fourth step of reducing the effective value of the charge / discharge current by a predetermined decrease when the determination is made . The moving average time is set to a plurality of times including at least a short time set in advance and a long time set to a time longer than the short time, and the effective current average threshold is set for each of the plurality of moving average times. Is set,
When it is determined that the charge / discharge current effective value is less than the charge / discharge current threshold value, it is determined whether or not the effective current moving average value is equal to or more than the effective current moving average threshold value for each moving average time. 6. The method for controlling a battery according to 5.

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