JP6190610B2 - Charge control device and mixer truck - Google Patents

Description

  The present invention relates to a charging control device that controls charging of a secondary battery, and a mixer vehicle equipped with the secondary battery.

  Conventionally, a battery (secondary battery) that charges electric power generated by a generator driven by an engine, an electric motor driven by electric power of the secondary battery, and a hydraulic motor driven based on the operation of the engine or electric motor, There is known a mixer vehicle in which a drum is rotated by a hydraulic motor driven by an electric motor when the engine is stopped (see Patent Document 1).

Japanese Patent Laid-Open No. 2003-301802

  In the prior art, a generator is generated by an engine, and this battery is charged with this electric power. When the engine is stopped, the electric motor can be driven using the electric power of the battery, the hydraulic motor can be driven based on the power of the electric motor, and the rotation of the drum can be continued. With such a configuration, the engine can be idling stopped, so noise and exhaust can be reduced and fuel efficiency can be improved.

  By the way, generally, when the battery is continuously charged when the battery temperature is low (low temperature), there is a problem that the battery deteriorates. Therefore, it is necessary to keep the charging rate low at such low temperatures.

  However, since the current supplied by the generator is usually constant, if the charge rate by this constant current is higher than the allowable charge rate that does not cause battery deterioration even when continuously charged at low temperatures, The battery deteriorates when charged.

  The present invention has been made in view of such problems, and provides a charge control device and a mixer vehicle that can be charged while suppressing deterioration of the secondary battery even when the temperature of the secondary battery is low. For the purpose.

The charging control device of the present invention is a charging control device that charges a secondary battery with electric power output from a generator, a switch that performs on / off control of electric power flowing between the generator and the secondary battery, and a secondary battery A determination unit that determines whether or not the battery temperature is lower than a deterioration threshold value due to charging of the secondary battery, and if the determination unit determines that the temperature of the secondary battery is lower than the deterioration threshold value, the switch is turned on / off. An intermittent charge control unit that controls and intermittently charges the secondary battery, the generator is an alternator that outputs a direct current, and the degradation threshold is a value of the direct current output from the alternator and a secondary value Indicates the upper limit of the charge rate calculated from the ratio to the rated capacity of the battery, and is set based on the relationship between the allowable charge rate , which is a charge rate that can be continuously charged while suppressing deterioration of the secondary battery, and the temperature of the secondary battery And intermittent charge control , If the temperature of the secondary battery by the determining unit is determined to be more degraded threshold, and controls to turn on the switch, it is continuously charge the secondary battery.

  According to the present invention, the secondary battery is configured to be intermittently charged when it is determined that the temperature of the secondary battery is lower than the deterioration threshold for preventing deterioration due to charging of the secondary battery. As a result, when the temperature of the secondary battery is lower than the deterioration threshold, the charge rate can be lowered, and charging can be performed while suppressing the deterioration of the secondary battery.

It is a schematic block diagram which shows the mixer truck of embodiment of this invention. It is an electric circuit diagram centering on the battery of the embodiment of the present invention. It is a figure which shows an example of the relationship between the battery temperature of embodiment of this invention, and an allowable charge rate. It is a flowchart of the charge control which the controller of embodiment of this invention performs. It is a figure which shows the waveform of the charging current of the pulse charge and continuous charge of embodiment of this invention.

  Hereinafter, a mixer vehicle 1 according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a mixer truck 1 according to an embodiment of the present invention.

  The mixer vehicle 1 is configured to rotate the drum 4 by driving the hydraulic pump 11 of the hydraulic circuit 10 by the output of the traveling engine 2.

  The hydraulic circuit 10 includes a hydraulic pump 11 and a hydraulic motor 12. The output of the engine 2 is transmitted to the hydraulic pump 11 via a power transmission mechanism 3 including, for example, a sprocket and a chain. The hydraulic pump 11 generates hydraulic pressure by being rotated by the engine 2. The hydraulic pressure generated by the hydraulic pump 11 rotates the hydraulic motor 12. The rotation of the hydraulic motor 12 is transmitted to the drum 4 via the speed reducer 5 to rotate the drum 4.

  The output of the engine 2 is also transmitted to the generator 30 via the power transmission mechanism 3. The generator 30 generates power by being rotated by the engine 2. The electric power generated by the generator 30 is charged in the battery 50 under the control of the controller 40. The battery 50 is composed of, for example, a lithium ion secondary battery. The electric power charged in the battery 50 is used when the electric motor 61 is driven.

  An auxiliary hydraulic circuit 60 is connected to the hydraulic circuit 10 via a switching valve 63. The auxiliary hydraulic circuit 60 includes an auxiliary hydraulic pump 62 that is driven by an electric motor 61. The auxiliary hydraulic pump 62 generates hydraulic pressure in the auxiliary hydraulic circuit 60.

  The switching valve 63 is provided with three positions: a neutral position where the hydraulic pressure of the auxiliary hydraulic circuit 60 is not supplied to the hydraulic circuit 10, a forward rotation position where the drum 4 is rotated forward, and a reverse rotation position where the drum 4 is rotated backward. The switching valve 63 is switched to the neutral position when the engine 2 is operated, and is switched to the forward rotation position or the reverse rotation position according to the control state of the drum 4 when the engine 2 is stopped.

  Next, the operation of the mixer truck 1 configured as described above will be described.

  The mixer truck 1 is loaded with ready-mixed concrete on the drum 4 in a concrete plant and transports it to the site. When discharging the ready-mixed concrete during transportation or at the placement site, the drum 4 is rotated to stir or discharge the ready-mixed concrete. The drum 4 is rotated by driving the hydraulic motor 12 with the hydraulic pressure of the hydraulic pump 11 rotated by the engine 2 as described above.

  In the mixer vehicle 1, in order to reduce exhaust gas and noise and improve fuel efficiency, for example, an idling stop that stops the engine 2 when the concrete is stopped, such as when putting concrete in a concrete plant, waiting for a signal, or waiting at the site. Is done. Since the engine 2 is stopped and the hydraulic pump 11 is not driven while idling is stopped, the rotation of the drum 4 is stopped as it is.

  In order to prevent the rotation of the drum 4 from being stopped, the hydraulic pressure is supplied by the auxiliary hydraulic pump 62 of the auxiliary hydraulic circuit 60 to rotate the drum 4 while the engine 2 is stopped. In this case, the controller 40 switches the switching valve 63 to the normal rotation position or the reverse rotation position according to the control state of the drum 4, and drives the electric motor 61 using the electric power charged in the battery 50. As the electric motor 61 is driven, the auxiliary hydraulic pump 62 rotates to generate hydraulic pressure in the auxiliary hydraulic circuit 60. This hydraulic pressure is transmitted from the auxiliary hydraulic circuit 60 to the hydraulic circuit 10 via the switching valve 63 to rotate the hydraulic motor 12. As a result, the drum 4 rotates forward or reverse. Therefore, the rotation of the drum 4 can be maintained even when the engine 2 is idling stopped.

  As described above, when the electric motor 61 is driven, the power of the battery 50 is consumed. Therefore, in the mixer vehicle 1, during operation of the engine 2, the generator 30 is generated by the rotation of the engine 2, and the generated power is charged in the battery 50.

  Next, charging control of the battery 50 will be described.

  FIG. 2 is an explanatory diagram of the electric circuit 41 centering on the battery 50 according to the embodiment of the present invention.

  The electric circuit 41 is connected to the generator 30 and the battery 50 via the first switch 51, and is connected to the battery 50 and the electric motor 61 via the second switch 52. The first switch 51 and the second switch 52 are constituted by semiconductor switches such as FETs. A diode 511 for protecting against reverse voltage is connected in parallel to the first switch 51, and a diode 512 for preventing reverse current from flowing to the battery 50 due to the operation of the generator 30 is connected in series. ing. In FIG. 2, a solid line indicates a current flow path, and a dotted line indicates a flow of a control signal.

  The controller 40 performs power generation control of the generator 30, charge control of the battery 50, drive control of the electric motor 61, and switch control of the first switch 51 and the second switch 52.

  In the electric circuit 41, when the generator 30 is generated by driving the engine 2 to charge the battery 50, the controller 40 sets the first switch 51 in the conductive state (ON) and the second switch 52 in the non-conductive state (OFF). ). Thereby, the circuit of the generator 30 and the battery 50 is closed, and the electric power generated by the generator 30 is charged in the battery 50.

  On the other hand, when the electric motor 61 is driven by the electric power of the battery 50, the first switch 51 is turned off (OFF) and the second switch 52 is turned on (ON). Thereby, the circuit of the battery 50 and the electric motor 61 is closed, and the electric motor 61 is driven by the power of the battery 50.

  Thus, the controller 40 can switch between the charging of the battery 50 and the driving of the electric motor 61 by switching the conduction state of the first switch 51 and the second switch 52.

  The controller 40 acquires a charge / discharge state such as a battery temperature and a remaining capacity (SOC: State of Charge) of the battery capacity from the battery 50. For example, when the battery 50 is not fully charged, the first switch 51 and the second switch 52 are switched to charge the battery 50 with the power generated by the generator 30. For example, when the engine 2 is stopped due to idling stop, the controller 40 switches the first switch 51 and the second switch 52 to drive the electric motor 61 using the electric power charged in the battery 50.

  Incidentally, it is known that the charge / discharge characteristics of the battery 50 generally change depending on the temperature. In particular, when the battery temperature is low, the battery 50 deteriorates unless the charging rate is kept low and continuous charging is performed.

  FIG. 3 is an explanatory diagram illustrating an example of the relationship between the battery temperature and the allowable charge rate of the battery 50 according to the embodiment of this invention.

  The charge rate is 1C when the rated current is supplied to the battery 50 and charged at the rated time. When the current value is larger than that, the charge rate is greater than 1C, and when the current value is small, the charge rate. Becomes smaller than 1C. For example, when the rating of the battery 50 is 40 Ah, when the charging rate is 1 C, a current of 40 A is supplied to the battery 50 so that the battery 50 is fully charged after one hour. In this embodiment, the generator 30 is comprised by the alternator which outputs a DC voltage as an example. Since the charging current by the generator 30 is set to be the same as the rated current of the battery 50, the charging rate when the battery 30 is continuously charged from the generator 30 is 1C. Further, the deterioration of the battery 50 means that the upper limit of the capacity that can be charged to the battery 50 is reduced.

  A solid line shown in FIG. 3 indicates an allowable charging rate of the battery 50 with respect to the temperature of the battery 50. The allowable charging rate indicates the upper limit of the charging rate at the battery temperature, and indicates that the battery 50 deteriorates when charging is performed at a charging rate that exceeds the allowable charging rate at the battery temperature.

  In FIG. 3, the battery temperature at which the allowable charging rate is 1C is T1, and the allowable charging rate decreases as the battery temperature becomes lower than T1. Therefore, when the battery temperature is lower than T1, it is necessary to charge less than 1C in order to prevent deterioration of the battery 50. However, the generator 30 is set so as to perform charging at a charging rate of 1C, and is not configured to output a current smaller than the rated current.

  When the generator 30 is generating electricity at the rotational speed of the engine 2 during normal operation of the mixer vehicle 1, the charging rate when continuously charging the battery 50 from the generator 30 cannot be made smaller than 1C. Therefore, when the battery temperature is lower than T1, if the battery 30 is continuously charged, the allowable charging rate is exceeded. The maximum battery temperature T1 at which the allowable charge rate is less than 1C is set as the deterioration threshold value of the battery 50.

  In order to prevent the deterioration of the battery 50, it is conceivable to provide a control circuit such as an inverter so that the charging current of the generator 30 can be controlled. However, in this case, there is a problem that cost, size, and weight increase.

  Therefore, in the present embodiment, as described below, when the battery temperature is lower than the deterioration threshold value T1, the battery 50 is prevented from being deteriorated by intermittently charging. That is, when the battery temperature is lower than the deterioration threshold T1 as described above, the controller 40 intermittently switches the first switch 51 and performs pulse charging (intermittent charging) instead of continuous charging on the battery 50. .

  The controller 40 acquires the temperature of the battery 50. The controller 40 stores in advance a table associating the battery temperature with the allowable charge rate as shown in FIG. The controller 40 has a storage unit for storing this table. The controller 40 refers to this table and obtains an allowable charge rate corresponding to the current battery temperature.

  When the allowable charging rate with respect to the current battery temperature is higher than 1C, that is, when the battery temperature is higher than the deterioration threshold T1, the controller 40 continuously supplies the current generated by the generator 30 to the battery 50. The battery 50 is continuously charged.

  On the other hand, when the allowable charging rate with respect to the current battery temperature is less than 1C, that is, when the battery temperature is lower than the deterioration threshold T1, the controller 40 intermittently supplies the current generated by the generator 30 to the battery 50. To supply the battery 50 with pulse charge.

  Next, details of the charge control will be described with reference to FIG. FIG. 4 is a flowchart of charge control executed by the controller 40 according to the embodiment of the present invention.

  The controller 40 executes the charging control process shown in the flowchart of FIG. 4 when the mixer vehicle 1 is activated. For example, when the main switch of the mixer truck 1 is turned on, it is determined that the mixer truck 1 is activated, and charging control is executed.

  First, in step S10, the controller 40 determines whether or not the engine 2 is in operation. When the engine 2 is in operation, the process proceeds to step S20. On the other hand, when the engine 2 is stopped by idling stop, for example, the process proceeds to step S100.

  In step S20, the controller 40 switches the switching valve 63 to the neutral position. At this time, the drum 4 rotates based on the power of the engine 2. After step S20, in step S30, the controller 40 determines whether or not the battery 50 is fully charged. The controller 40 constantly acquires the remaining capacity SOC of the battery 50 and determines whether or not the battery 50 is fully charged based on the remaining capacity SOC. The fully charged state refers to a case where the remaining capacity SOC of the battery 50 is equal to or greater than a predetermined value. This predetermined value is appropriately set according to the type of the battery 50 and the like.

  If the battery 50 is fully charged, the battery 50 does not need to be charged, so the process returns to step S10 and the process is repeated. If the battery 50 is not fully charged, the process proceeds to step S40 in order to charge the battery 50. In step S <b> 40, the controller 40 executes power generation control by the generator 30.

  Next, it transfers to step S50 and the controller 40 determines whether the battery temperature acquired from the battery 50 is less than the degradation threshold value T1.

  When it is determined that the battery temperature is lower than the deterioration threshold T1, the process proceeds to step S60, and the controller 40 performs pulse charging on the battery 50. Specifically, a period for turning on the first switch 51 and a period for turning off the first switch 51 are set, and the ON period and the OFF period are repeated to turn the first switch 51 on and off. Thereby, the electric power generated by the generator 30 is intermittently supplied to the battery 50, and the battery 50 is pulse-charged. During this time, the second switch 52 is set to OFF.

  The pulse charging is charging in which a charging period for supplying a current with a charging rate of 1 C to the battery 50 and a stop period for not supplying a current to the battery 50 are repeated every predetermined intermittent period. The example shown in FIG. 5 (A) shows an example of the waveform of the charging current of pulse charging when the charging period is 2 seconds, the stop period is 5 seconds, and the intermittent period is 7 seconds.

  The controller 40 performs pulse charging by controlling ON / OFF of the first switch 51. Specifically, the first switch 51 is turned on for 2 seconds to supply current from the generator 30 to the battery 50, and then the first switch 51 is turned off for 5 seconds to stop charging the battery 50. By repeating this, pulse charging is performed. Note that the second switch 52 is always set to OFF during pulse charging.

  Thus, the controller 40 can charge at a charging rate represented by the ratio of the charging period to the intermittent period by performing pulse charging by controlling the charging period and the stop period. For example, in the example of FIG. 5A, the charging period with respect to the intermittent period is 2 / (2 + 5) = 0.28. This is the same charging rate as when continuous charging at 0.28 C is performed by pulse charging.

  As described above, when charging is performed using the generator 30 that is set to charge at 1 C, the battery temperature is less than the deterioration threshold T1, and the allowable charging rate is the charging of the generator 30. Even when the rate is lower than the rate, charging at a rate lower than the allowable charging rate can be performed by performing pulse charging.

  As shown in FIG. 3, when the battery temperature is less than the deterioration threshold T1, the lower the battery temperature, the lower the allowable charge rate. Since the controller 40 can vary the ratio between the charging period and the stop period (that is, the duty ratio) according to the allowable charging rate corresponding to the battery temperature, the allowable charging is performed when the battery temperature is less than the deterioration threshold T1. The charging of the battery 50 can be controlled by ON / OFF control of the first switch 51 so that the duty ratio becomes smaller as the rate becomes lower. In addition, when the temperature of the battery 50 is less than the deterioration threshold value T1, it is preferable to make the charge rate of the battery 50 substantially coincide with the allowable charge rate. Thereby, it is possible to charge the battery 50 efficiently and quickly while suppressing deterioration of the battery 50. Moreover, when it is desired to suppress the deterioration of the battery 50, it is preferable to set the charging rate of the battery 50 to be lower than the allowable charging rate.

  In step S50 of FIG. 4, when the battery temperature is not less than the deterioration threshold T1, the process proceeds to step S70, and the controller 40 continuously charges the battery 50. Specifically, the first switch 51 in FIG. 2 is set to ON and the second switch 52 is set to OFF, and the power generated by the generator 30 is continuously supplied to the battery 50, so that the battery 50 is continuously charged. Is done.

  In this case, as shown in FIG. 5B, the current supplied from the generator 30 is continuously charged to the battery 50 at the charge rate 1C.

  After the processes in steps S60 and S70, the controller 40 returns to the process in step S10 again.

  If the controller 40 determines in step S10 that the engine 2 has been stopped, the process of step S100 is executed. The controller 40 sets the switching valve 63 so that the hydraulic pressure of the auxiliary hydraulic circuit 60 is supplied to the hydraulic circuit 10 by switching to the forward rotation position or the reverse rotation position according to the control state of the drum 4.

  In step S <b> 110, the controller 40 drives the electric motor 61 with the electric power of the battery 50. At this time, the controller 40 sets the first switch 51 to OFF and the second switch 52 to ON, and connects the circuit of the battery 50 and the electric motor 61 to drive the electric motor 61. When the electric motor 61 is driven, the auxiliary hydraulic pump 62 rotates and the hydraulic oil discharged from the auxiliary hydraulic pump 62 is supplied to the hydraulic circuit 10 via the switching valve 63 to rotate the hydraulic motor 12 forward or backward.

  By the process of step S110, the rotation of the drum 4 can be continued even when the engine 2 is stopped. After the process of step S110, the process returns to step S10 and the process is repeated.

  As described above, the embodiment of the present invention is a charge control device (controller 40) that charges the battery 50 that is a secondary battery with the power from the generator 30 that is a power generation source. 50 is configured as a determination unit that determines whether or not the detected temperature is lower than a deterioration threshold value T1 for preventing deterioration when charging the battery 50, and the battery 50 is determined by the determination unit. When it is determined that the temperature of the battery is lower than the deterioration threshold value T <b> 1, an intermittent charge control unit that intermittently charges the battery 50 is provided. Moreover, the controller 40 has a continuous charge control part which charges the battery 50 continuously, when the judgment part judges that the temperature of the battery 50 is more than the deterioration threshold value T1.

  With such a configuration, when the battery temperature is lower than the deterioration threshold T1, the charging rate represented by the duty ratio between the charging period and the stop period is less than the allowable charging rate by charging the battery 50 intermittently. Therefore, even when the battery temperature is low, the battery 50 can be charged so that the battery 50 is not deteriorated.

  Further, by charging the battery 50 with the engine 2, the engine 2 can be idling stopped without stopping the rotation of the drum 4 while increasing the charging capacity of the battery 50 as much as possible. Thereby, noise and exhaust gas can be reduced and fuel efficiency can be improved. Moreover, it is not necessary to provide a control circuit such as an inverter that can control the current of the generator 30, and the cost, size, and weight are not increased.

  In addition, when the battery 50 is intermittently charged, the charging is performed by controlling the first switch 51 and the second switch 52 that are semiconductor switches. Power loss is small due to ON / OFF control by the semiconductor switch, and charging can be performed intermittently with a simple configuration.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  In the above embodiment, the battery 50 is charged by the generator 30 that is driven by the engine 2 to generate power, but is not limited thereto. For example, an external power source such as a commercial power source may be used as a power generation source in a plant, a standby site, a placement site, or the like, and the battery 50 may be charged by the external power source. Also in this case, when the battery temperature is lower than the deterioration threshold, intermittent charging can be performed as described above.

  In the above embodiment, the current supplied from the generator 30 is set to be the rated current of the battery 50 and charging is performed at a charging rate of 1 C. However, the present invention is not limited to this. You may set the electric current which the generator 30 supplies to 1 C or more. In this case, the pulse charge control is executed so that the charge rate when continuously charged by the current supplied by the generator 30 does not exceed the allowable charge rate shown in FIG.

DESCRIPTION OF SYMBOLS 1 Mixer car 2 Engine 4 Drum 10 Hydraulic circuit 11 Hydraulic pump 12 Hydraulic motor 30 Generator 40 Controller (a judgment part, intermittent charge part, memory | storage part)
50 Battery 51 First Switch 52 Second Switch 60 Auxiliary Hydraulic Circuit 61 Electric Motor 62 Auxiliary Hydraulic Pump 63 Switching Valve

Claims (4)

A charge control device for charging a secondary battery with electric power output from a generator,
A switch for on / off control of power flowing between the generator and the secondary battery;
A determination unit for determining whether the temperature of the secondary battery is lower than a deterioration threshold value due to charging of the secondary battery;
When the determination unit determines that the temperature of the secondary battery is lower than the deterioration threshold, the switch is turned on and off to intermittently charge the secondary battery,
With
The generator is an alternator that outputs a direct current,
The deterioration threshold indicates an upper limit of a charging rate calculated from a ratio of a direct current value output from the alternator and a rated capacity of the secondary battery, and charging capable of continuous charging while suppressing deterioration of the secondary battery. Set based on the relationship between the allowable charge rate that is the rate and the temperature of the secondary battery,
When the determination unit determines that the temperature of the secondary battery is equal to or higher than the deterioration threshold, the intermittent charge control unit controls the switch to be turned on to continuously charge the secondary battery. A charge control device. A storage unit that stores a table associating the temperature of the secondary battery with an allowable charge rate that is a charge rate that can be continuously charged while suppressing deterioration of the secondary battery;
The charge control device according to claim 1, wherein the intermittent charge control unit performs charge at a charge rate lower than the allowable charge rate according to a temperature of the secondary battery.   The charge control device according to claim 1, wherein the intermittent charge control unit intermittently charges the secondary battery by controlling a duty ratio of the switch.   A mixer vehicle comprising the charge control device according to any one of claims 1 to 3.

Images