JP2015082948A - Charger, and electric vehicle mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger capable of charging with a preferable condition according to an amount of charge and a charge time.SOLUTION: Based on a command from a control device, a charging circuit makes a charge current flow having a magnitude directed from the control device to a power storage device. The control device directs the magnitude of the charge current to the charging circuit on the basis of a target amount of charge, which is the quantity of electricity to be charged to the power storage device and a target charging time to make the power storage device a fully charged state.

Description

  The present invention relates to a charging device for charging a power storage device, and an electric vehicle equipped with the charging device.

  In an electric vehicle such as an electric forklift, charging is performed at night when the vehicle is not used. In the charging method disclosed in Patent Document 1, charging is performed to a fully charged state after the work is completed, and supplementary charging is started immediately before the work start time on the next day. By performing supplementary charging, the amount of charge reduced by self-discharge from the time when the fully charged state is reached to the time when the work is started is supplemented. Thereby, work can be started in a state where the power storage device is fully charged.

  In the method disclosed in Patent Document 2, the charging current is changed according to the environmental temperature. Thereby, it can charge with appropriate charge conditions.

  A multi-stage constant current charging method is known as a method for charging a power storage device such as a lead storage battery. In this method, the charging current is decreased stepwise as the charging time elapses. In the initial stage where the cell voltage is low, the charging voltage is set to a low value, thereby suppressing side reactions and setting the charging current to a large value, thereby shortening the entire charging time. . At the final stage when the cell voltage has increased, charging is performed with a small current that does not lead to gas generation.

JP-A-9-271142 JP 2005-27479 A

  The power consumption of the storage battery depends on the daytime work mode and the actual working hours. When the power consumption of the storage battery fluctuates, the amount of charge until the battery is fully charged also fluctuates. When the work end time varies, the charging time from the work end to the next day work start varies. Thus, the charge amount and the charge time vary from day to day. Conventionally, charging is performed under substantially the same charging conditions even if the charging amount and charging time vary. For this reason, it cannot always be said that charging was performed under optimum charging conditions.

  The objective of this invention is providing the charging device which can charge on preferable conditions according to charge amount and charging time. Another object of the present invention is to provide an electric vehicle equipped with this charging device.

According to one aspect of the invention,
A control device;
Based on a command from the control device, a charging circuit having a charging current of a magnitude commanded from the control device, and a charging circuit that flows to the power storage device,
The control device supplies the charging circuit with a magnitude of the charging current based on a target charge amount that is an amount of electricity to be charged in the power storage device and a target charge time until the power storage device is fully charged. A charging device for commanding is provided.

According to another aspect of the invention,
The above charging device;
A power storage device;
An electric vehicle having an electric motor driven by discharge power from the power storage device is provided.

  Regardless of the target charging time, in the method of charging with a predetermined charging current, when the required charge amount is small, the battery may be fully charged in a time significantly shorter than the target charging time. In the present invention, since the magnitude of the charging current is commanded based on the target charging amount and the target charging time, the charging current has a more preferable magnitude compared to the case where charging is performed with a predetermined charging current. It is possible to charge. For example, according to the target charging time, it is possible to perform charging with more preferable charging conditions, for example, with a charging current as small as possible.

FIG. 1A is a block diagram of an electric vehicle according to an embodiment, and FIG. 1B is a correlation diagram of various parameters handled by the control device. FIG. 2 is a graph showing an example of a time change in the operating state of the electric vehicle and a time change in the charging state of the power storage device. FIG. 3 is a chart showing an example of the charge pattern correspondence table. FIG. 4A is a graph showing the time change of the charging current defined by the charge patterns PTN1 to PTN3, and FIG. 4B is a graph showing the time change of the charge state when charging is performed under the conditions of the charge patterns PTN1 to PTN3. It is. FIG. 5A is a graph showing a time change of the charging current defined by the charging patterns PTN2, PTN5, and PTN8, and FIG. 5B is a charging state time when charging is performed under the conditions of the charging patterns PTN2, PTN5, and PTN8. It is a graph which shows a change. FIG. 6A is a graph showing the time change of the charging current defined by the charging pattern PTN1 and the charging pattern PTNc according to the comparative example, and FIG. 6B is a charging state when charging is performed under the conditions of the charging patterns PTN1 and PTNc. It is a graph which shows the time change of. FIG. 7A is a block diagram of a charging device and an electric vehicle according to another embodiment, and FIG. 7B is a correlation diagram of various parameters handled by the control device for the electric vehicle according to the embodiment shown in FIG. 7A. FIG. 8 is a correlation diagram of various parameters handled by a control device for an electric vehicle according to still another embodiment. FIG. 9 is a correlation diagram of various parameters handled by a control device for an electric vehicle according to still another embodiment.

  FIG. 1A shows a block diagram of an electric vehicle 10 according to the embodiment. Examples of the electric vehicle 10 according to the embodiment include an electric forklift, an electric automatic guided vehicle (AGV), and an electric cleaning robot. These electric vehicles operate in a specific time zone and are used in a form in which charging is performed during a period until the next operation time zone. For example, an electric forklift generally operates during work hours from morning to evening and is charged at night. Electric automatic guided vehicles are used in factory production lines, luggage distribution centers, and the like. In general, a plurality of electric automatic guided vehicles are prepared in one transfer area, some electric automatic guided vehicles are operating, and other electric automatic guided vehicles are on standby. During the standby, the electric automatic guided vehicle is charged. When the remaining battery level of the electrically operated automated guided vehicle is reduced, the activated automated guided vehicle is replaced with the standby automated guided vehicle. The electric cleaning robot operates within the closing time of the facility where it is deployed, and is charged while the facility is open.

  A charging device 20, a power storage device 30, and an electric load 35 are mounted on the electric vehicle 10. For the power storage device 30, for example, a secondary battery such as a lead storage battery is used. Note that a nickel hydride secondary battery, a lithium ion secondary battery, an electric double layer capacitor, a lithium ion capacitor, or the like may be used for the power storage device 30. For example, an inverter and an electric motor are used for the electric load 35.

  The charging device 20 includes a charging circuit 21, a control device 22, and an input terminal 23. Power, for example, three-phase AC power is supplied from the commercial power supply 11 to the input terminal 23. Charging circuit 21 converts alternating current into direct current based on a command from control device 22, and supplies a charging current to power storage device 30. The magnitude of the charging current is commanded from the control device 22.

  A charging path relay 33 and a charging current sensor 32 are inserted in a charging path that connects the charging circuit 21 and the power storage device 30. Charging current sensor 32 measures the charging current of power storage device 30. The measurement result of the charging current sensor 32 is input to the control device 22. The charging path relay 33 turns on and off the charging path. Voltage sensor 31 measures a voltage between terminals of power storage device 30. The measurement result of the voltage sensor 31 is input to the control device 22.

  Electric load 35 is driven by the discharged power from power storage device 30. A discharge path relay 34 and a discharge current sensor 36 are inserted in a discharge path connecting the power storage device 30 and the electric load 35. The discharge path relay 34 turns on and off the discharge path. The discharge current sensor 36 measures the discharge current. The measurement result of the discharge current sensor 36 is input to the control device 22.

  When the power storage device 30 is charged, the charging path relay 33 is turned on and the discharging path relay 34 is turned off. During the period when the electric vehicle 10 is operating, the charging path relay 33 is turned off and the discharging path relay 34 is turned on.

  When the electric vehicle 10 is an electric forklift, the electric load 35 includes, for example, a travel motor, a fork lifting motor, a control circuit, and the like. When the electric vehicle 10 is an electric automatic guided vehicle, the electric load 35 includes, for example, a travel motor, a travel route sensor, a control circuit, and the like. When the electric vehicle 10 is an electric cleaning robot, the electric load 35 includes, for example, a travel motor, a suction motor, an obstacle sensor, a control circuit, and the like.

  FIG. 1B shows a correlation diagram of various parameters handled by the control device 22. The control device 22 includes a storage device, and the storage capacity Cc, the scheduled operation start time Ts, and the charge pattern correspondence table 40 are stored in the storage device. The storage capacity Cc means the amount of electricity that can be discharged from the fully charged state (the charged state SOC is 100%). The storage capacity Cc is used when calculating the amount of electricity required to charge the storage device 30 from the current state to the fully charged state. When the electric vehicle 10 is an electric forklift, the scheduled operation start time Ts corresponds to, for example, a day work start time. When the electric vehicle 10 is an electric automatic guided vehicle, the scheduled operation start time Ts corresponds to a time scheduled to be replaced with an electric automatic guided vehicle currently in operation. When the electric vehicle 10 is an electric cleaning robot, the scheduled operation start time Ts corresponds to a time later than the facility closing time.

  Next, with reference to FIG. 2, an example of the time change of the operating state of the electric vehicle 10 (FIG. 1A) and the time change of the charging state of the power storage device 30 (FIG. 1A) will be described. As will be described below, the state of charge at the start of charging and the time available for charging vary from day to day.

The upper part of FIG. 2 shows an example of the time change in the working state and the resting state, and the lower part of FIG. 2 shows an example of the time change of the charging state of the power storage device 30 (FIG. 1A). The horizontal axis of FIG. 2 represents time, and the time change from the morning of the first day to the morning of the fourth day is shown. Work starts at 8 am every day. That is, the scheduled operation start time Ts is 8:00.

  The work end times vary from day to day, and the work end times on the first to third days are 17:00, 21:00, and 14:00, respectively. Charging is performed during the period from the end of work on one day to the start of work on the next day (resting period). Since it is only necessary to complete the charging by the work start time on the next day, the target charging time Tt on the first day to the third day is obtained as 15 hours, 11 hours, and 18 hours, respectively. During the work, the state of charge decreases with the passage of time according to the operating state of the electric vehicle 10. During the suspension, the state of charge of the power storage device 30 increases. The charge state becomes 100% at the scheduled operation start time Ts.

  The description will be continued with reference to FIG. 1B. When the work for one day is completed, the control device 22 turns off the discharge path relay 34 (FIG. 1A) and turns on the charge path relay 33 (FIG. 1A). Voltage sensor 31 measures open circuit voltage Vcc of power storage device 30. The current state of charge SOCc is obtained from the measured open circuit voltage Vcc. Here, the state of charge when fully charged is defined as 100%. Note that other methods may be applied as a method of calculating the current state of charge SOCc of the power storage device 30. For example, the state of charge SOCc can be calculated from the current-voltage characteristics of the power storage device 30.

  Control device 22 calculates target charge amount Ct from state of charge SOCc and storage capacity Cc. Here, the target charge amount Ct means a charge amount required until the power storage device 30 is fully charged. Further, the control device 22 calculates a target charging time Tt from the scheduled operation start time Ts and the current time Tc. As an example, the target charging time Tt is equal to the time from the current time Tc to the scheduled operation start time Ts on the next day.

  For example, a multistage constant current charging method is applied to charge the power storage device 30. In the charge pattern correspondence table 40, a plurality of charge patterns that define the time change of the charge current of the multistage constant current charging method are defined in advance. The control device 22 selects one charge pattern from the charge pattern correspondence table 40 based on the target charge amount Ct and the target charge time Tt. Based on the selected charging pattern, the charging circuit 21 is instructed for the magnitude of the charging current.

  FIG. 3 shows an example of the charge pattern correspondence table 40 (FIG. 1B). Three types of target charging time Tt, 11 hours, 15 hours, and 18 hours, are prepared, and three types of target charging amounts Ct, C0, C1, and C2, are prepared. Here, the relationship of C0 <C1 <C2 is established. Charging patterns PTN1 to PTN9 are associated with combinations of the target charge amount Ct and the target charge time Tt, respectively.

  FIG. 4A shows a change with time of the charging current defined by the charging patterns PTN1 to PTN3. In any of the charging patterns PTN1 to PTN3, the target charging time Tt is 18 hours as shown in FIG. The target charge amounts Ct of the charge patterns PTN1 to PTN3 are C0, C1, and C2, respectively. In any of the charging patterns PTN1 to PTN3, the charging current decreases stepwise with time.

FIG. 4B shows the time change of the charging state when charging is performed under the conditions of the charging patterns PTN1 to PTN3. At the time of 14:00, which is the work end time, there is a difference in the state of charge for each of the charge patterns PTN1 to PTN3. The charge amounts necessary for charging the charge patterns PTN1 to PTN3 from the charge states SOC1 to SOC3 to the fully charged state at the work end time are C0 to C2 (FIG. 3), respectively. The charging state increases with time. Charge pattern PTN1 so that the value obtained by integrating the charge current (FIG. 4A) with time matches the target charge amount Ct.
~ PTN3 is defined. For this reason, in any charge pattern PTN1 to PTN3, the charge state reaches 100% at the time of 8:00 am, which is the scheduled operation start time Ts.

  FIG. 5A shows changes with time of the charging current defined by the charging patterns PTN2, PTN5, and PTN8. The target charging times Tt of the charging patterns PTN2, PTN5, and PTN8 are 18 hours, 15 hours, and 11 hours, respectively, as shown in FIG. In any charge pattern PTN2, PTN5, or PTN8, the target charge amount Ct is equal to C1 (FIG. 3).

  FIG. 5B shows a time change of the charging state when charging is performed under the conditions of the charging patterns PTN2, PTN5, and PTN8. The charging state at 17:00 and 21:00, which are the work end times of the charging patterns PTN5 and PTN8, is equal to the charging state SOC2 at 14:00, which is the work end time of the charging pattern PTN2. The charging patterns PTN2, PTN5, and PTN8 are defined so that the value obtained by integrating the charging current (FIG. 5A) with time matches the target charge amount Ct. For this reason, in any of the charging patterns PTN2, PTN5, and PTN8, the charging state reaches 100% at 8:00 am, which is the scheduled operation start time Ts.

  With reference to FIG. 6A and 6B, the effect of the charging method using the charging device 20 (FIG. 1A) by an Example is demonstrated.

  FIG. 6A shows changes over time in the charging current defined by the charging pattern PTN1 and the charging pattern PTNc according to the comparative example. FIG. 6B shows a time change of the charging state when charging is performed under the conditions of the charging patterns PTN1 and PTNc. The charge pattern PTN1 is the same as the charge pattern PTN1 shown in FIGS. 4A and 4B. At 14:00, which is the work end time, the charging state of the charging pattern PTNc according to the comparative example is the same as the charging state SOC1 of the charging pattern PTN1. In any of the charge patterns PTN1 and PTNc, the target charge amount Ct is equal to C0 (FIG. 3).

  When charging is performed with the charging pattern PTN1 according to the embodiment, the charging state reaches 100% at 8:00 am, which is the scheduled operation start time Ts. On the other hand, when charging is performed with the charging pattern PTNc according to the comparative example, the charging state reaches 100% before 8:00 am, and the charging current is 0 thereafter. Thus, the charging pattern PTNc according to the comparative example is set regardless of the length of time from the start of charging to the scheduled operation start time Ts.

  In the charging pattern PTNc according to the comparative example, a large charging current flows at the beginning of charging as compared with the charging pattern PTN1 according to the embodiment. In other words, by performing charging based on the charging pattern PTN1 according to the embodiment, it is possible to prevent the charging current from becoming excessively larger than necessary. Thereby, since the temperature rise of the electrical storage device 30 (FIG. 1) is suppressed, the lifetime of the electrical storage device is extended.

  Also in the other charging patterns PTN2 to PTN9 according to the embodiment, charging is performed using the entire time from the charging start time to the scheduled operation start time Ts. For this reason, it can be avoided that the charging current becomes excessively larger than necessary. Thereby, since the temperature rise of the electrical storage device 30 (FIG. 1) is suppressed, the lifetime of the electrical storage device is extended.

In the above embodiment, as shown in FIG. 3, the charging patterns PTN1 to PTN9 are defined for the three types of target charging time Tt and the three types of target charging amount Ct. When the target charge time Tt and the target charge amount Ct that are actually calculated are not defined in the charge pattern correspondence table 40, the longest target charge that does not exceed the target charge time Tt calculated by the control device 22 A charging pattern corresponding to the maximum target charge amount Ct and corresponding to the time Tt may be selected without exceeding the calculated target charge amount Ct.

  Based on the target charge amount Ct and the target charge time Tt, an optimal time change pattern of the charging current by the multistage charging method may be obtained each time. However, in this method, in order to obtain the optimal time change pattern of the charging current, a complicated calculation must be executed. By defining a plurality of charge patterns in advance as in the above embodiment, the time change pattern of the charge current can be easily determined without performing complicated calculations.

  In FIG. 3, the charging pattern is defined for the three types of target charging time Tt and the three types of target charging amount Ct, but the target charging time Tt and the target charging amount Ct may be further subdivided.

  In FIG. 4A, the charging currents of the charging patterns PTN2 and PTN3 are changed in three stages, and the charging current of the charging pattern PTN1 is changed in two stages. However, the number of stages for changing the charging current is two and three stages. It is not limited. The number of stages for changing the charging current may be four or more.

  By mounting the charging device 20 (FIG. 1A) according to the above-described embodiment on an electric vehicle that operates in a specific time zone and is used in a form in which charging is performed in a period until the next operating time zone, A remarkable effect is obtained.

  Another embodiment will be described with reference to FIGS. 7A and 7B. Hereinafter, differences from the embodiment shown in FIGS. 1A to 1B will be described, and description of the same configuration will be omitted.

  FIG. 7A shows a block diagram of the charging device 20 and the electric vehicle 10 according to this embodiment. In the embodiment shown in FIG. 1A, the charging device 20 is mounted on the electric vehicle 10. However, in the embodiment shown in FIG. 7A, the charging device 20 is disposed outside the electric vehicle 10. A control device 15 is mounted on the electric vehicle 10. Terminal 24 of charging device 20 and terminal 25 of electric vehicle 10 are connected to each other. A charging current flows from the charging circuit 21 to the power storage device 30 via the terminals 24 and 25 and the charging path relay 33.

  FIG. 7B shows a correlation diagram of various parameters handled by the control device 15 of the electric vehicle 10 (FIG. 7A) and the control device 22 of the charging device 20 (FIG. 7A). The types of parameters handled are the same as the types of parameters handled in the embodiment shown in FIG. 1B. In the embodiment shown in FIG. 7B, the process until the target charge amount Ct and the target charge time Tt are obtained is executed by the control device 15 of the electric vehicle 10. The obtained target charge amount Ct and target charge time Tt are transmitted from the control device 15 to the control device 22 of the charging device 20 via the terminals 25 and 24 (FIG. 7A).

  The control device 22 of the charging device 20 selects a charging pattern by referring to the charging pattern correspondence table 40 based on the target charging amount Ct and the target charging time Tt received from the electric vehicle 10.

  The charging device 20 according to the embodiment shown in FIGS. 7A and 7B operates for charging an electric vehicle that operates in a specific time period and is charged in a period until the next operation time period. By applying, a remarkable effect is obtained.

  Still another embodiment will be described with reference to FIG. The block diagram of the charging device 20 and the electric vehicle 10 according to this embodiment is the same as the block diagram shown in FIG. 7A.

FIG. 8 shows a correlation diagram of various parameters handled by the control device 15 and the control device 22 of the electric vehicle 10 according to this embodiment. Hereinafter, differences from the embodiment shown in FIG. 7B will be described, and description of the same configuration will be omitted. In the embodiment shown in FIG. 8, the processing until the current state of charge SOCc is obtained is executed by the control device 15 of the electric vehicle 10. The obtained state of charge SOCc, preset storage capacity Cc, and scheduled operation start time Ts are transmitted to the control device 22 of the charging device 20.

  Control device 22 of charging device 20 calculates target charge amount Ct based on state of charge SOCc and storage capacity Cc received from electrically powered vehicle 10. Further, the target charging time Tt is calculated based on the scheduled operation start time Ts and the current time Tc received from the electric vehicle 10. Thereafter, a charge pattern is selected by referring to the charge pattern correspondence table 40 based on the target charge amount Ct and the target charge time Tt.

  In the embodiment shown in FIG. 8, instead of receiving the target charge amount Ct itself from the electric vehicle 10, the charging device 20 receives information on the target charge amount Ct, that is, the state of charge SOCc and the storage capacity Cc. Further, instead of receiving the target charging time Tt itself, information on the target charging time Tt, that is, the scheduled operation start time Ts is received.

  Still another embodiment will be described with reference to FIG. Hereinafter, differences from the embodiment shown in FIG. 8 will be described, and description of the same configuration will be omitted. In the embodiment shown in FIG. 8, the current state of charge SOCc is calculated from the open circuit voltage Vcc of the power storage device 30 (FIG. 7A). In the embodiment shown in FIG. 9, the control device 15 of the electric vehicle 10 stores the time change of the charge / discharge current measured by the charge current sensor 32 and the discharge current sensor 36 (FIG. 7A). When the terminal 25 (FIG. 7A) of the electric vehicle 10 is connected to the terminal 24 (FIG. 7A) of the charging device 20, the control device 15 integrates the charging / discharging current with time, thereby charging and discharging the electric quantity. Q is calculated. The amount of electricity Q is initially set when the power storage device 30 is fully charged, that is, at the scheduled operation start time Ts. For this reason, the obtained amount of electricity Q matches the amount of electricity charged / discharged from the fully charged state.

  The obtained amount of electricity Q is transmitted to the control device 22 of the charging device 20. The control device 22 calculates a target charge amount Ct based on the amount of electricity Q received from the electric vehicle 10. In the present embodiment, the target charge amount Ct is equal to the amount of electricity Q received from the electric vehicle 10. The control device 22 selects a charge pattern by referring to the charge pattern correspondence table 40 based on the target charge amount Ct and the target charge time Tt.

  Also in the embodiment shown in FIGS. 7A to 9, the charging device 20 receives information on the target charge amount Ct and information on the target charge time Tt from the electric vehicle 10. By selecting an optimal charging pattern based on these pieces of information, as in the embodiment shown in FIG. 1A and FIG. The temperature rise of (FIG. 7A) can be suppressed.

  In the above embodiment, a suitable charge pattern is stored in advance in the charge pattern correspondence table 40 (FIG. 3). However, based on the information on the target charge amount Ct and the information on the target charge time Tt, an optimum charge pattern is stored. May be generated. In this case, the time change of the charging current is set so that the value obtained by integrating the charging current with time becomes equal to the target charge amount Ct (FIG. 1B and the like). Further, the change in charging current with time is set so that the charging state becomes 100% just before or just before the scheduled operation start time Ts.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Electric vehicle 11 Commercial power supply 15 Control apparatus 20 Charging apparatus 21 Charging circuit 22 Control apparatus 23 Input terminal 24, 25 Terminal 30 Power storage apparatus 31 Voltage sensor 32 Charging current sensor 33 Charging path relay 34 Discharging path relay 35 Electric load 36 Discharging current sensor 40 Charge Pattern Correspondence Table Cc Storage Capacity Ct Target Charge Amount PTN1 to PTN9 Charge Pattern Q Charged / Discharged Electricity SOC Charge State SOC1 Charge State SOC2 at the End of Work of Charge Pattern PTN1 Charge State SOC3 at the End of Work of Charge Pattern PTN2 Charge state SOCc at the end of work of charge pattern PTN3 Current charge state Tc Current time Ts Operation start time Tt Target charge time Vcc Open voltage

Claims (7)

A control device;
Based on a command from the control device, a charging circuit having a charging current of a magnitude commanded from the control device, and a charging circuit that flows to the power storage device,
The control device supplies the charging circuit with a magnitude of the charging current based on a target charge amount that is an amount of electricity to be charged in the power storage device and a target charge time until the power storage device is fully charged. A charging device that commands The controller is
A plurality of charging patterns defining a time change of the charging current are stored in association with the target charging amount and the target charging time,
2. The charging device according to claim 1, wherein the corresponding charging pattern is selected from the target charging amount and the target charging time, and the magnitude of the charging current is commanded to the charging circuit based on the selected charging pattern. .   The charging device according to claim 2, wherein the charging current defined by the charging pattern decreases stepwise as time elapses.   4. The charging according to claim 2, wherein the charging pattern defines a time change of the charging current so that the power storage device is fully charged when the target charging time has elapsed from the start of charging. apparatus.   The charging device according to claim 1, wherein the control device receives information on the target charging amount and information on the target charging time from an electric vehicle equipped with the power storage device.   The control device stores a scheduled operation start time of an electric vehicle equipped with the power storage device, and calculates the target charging time based on the scheduled operation start time and a current time. The charging device described. The charging device according to any one of claims 1 to 4,
A power storage device;
An electric vehicle having an electric motor driven by discharge power from the power storage device.

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