JP2006121874A - Power supply apparatus and vehicle equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply apparatus for rapidly progressing charging/discharging between a high-capacity battery and a high-output battery connected, in parallel. <P>SOLUTION: The high-capacity battery 110 and the high-output battery 120 having an internal resistor and a capacity smaller than the high-capacity battery 110 are connected in parallel via a DC-DC converter 130 for receiving a voltage from the high-capacity battery 110, boosting the voltage and applying the boosted voltage to the high-output battery 120. A controller 140 is provided, and switches a voltage boosting state for boosting the voltage using the DC-DC converter 130 and a voltage boosting stopping state for stopping the voltage boosting and connecting the high-capacity battery 110 and the high-output battery 120, in parallel. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply device and a vehicle equipped with the same. The present invention particularly relates to a power supply device in which a high-capacity battery and a high-power battery are connected in parallel, and a vehicle equipped with the same.

  Secondary batteries such as lithium ion batteries and nickel metal hydride batteries are actively developed as power sources for driving motors of electric vehicles (EV) and hybrid electric vehicles (HEV).

As a power source for driving a motor, a hybrid battery as shown in Patent Document 1 below has been proposed because of a demand for high capacity and high output. The hybrid battery disclosed in Patent Document 1 is a battery in which a high capacity battery (high energy density type battery) and a high output battery (high output density type battery) are connected in parallel. With such a configuration, current flows in a direction to reduce the potential difference between the high-capacity battery and the high-power battery, and charging / discharging between the two batteries proceeds.
Japanese Patent Laid-Open No. 11-332023

  However, in the above hybrid battery, charging / discharging between the two batteries proceeds slowly due to the potential difference between the two batteries that occurs as the motor is driven.

  Therefore, when the charge amount (SOC) of the high-power battery is remarkably reduced due to the discharge to the motor, the current supply from the high-capacity battery to the high-power battery cannot catch up, and the output of the high-power battery decreases. In addition, when a battery is heated by flowing current between a high-capacity battery and a high-power battery at a low temperature to prevent a decrease in battery output, it takes time for the battery to warm. It was.

  The present invention has been made to solve the above-described problems. Therefore, an object of the present invention is to provide a power source that can rapidly charge and discharge between batteries by forcibly generating a potential difference between a high-capacity battery and a high-power battery connected in parallel. Is to provide a device.

  The above object of the present invention is achieved by the following means.

  In the power supply device of the present invention, the first battery and the second battery having lower internal resistance and capacity than the first battery receive the voltage of the first battery and boost the voltage. It is characterized by being connected in parallel through boosting means applied to the battery.

  The vehicle of the present invention is equipped with the above power supply device.

  According to the power supply device of the present invention, in a battery in which a high-capacity battery and a high-power battery are connected in parallel, a potential difference is forcedly generated between the two batteries, so that charging / discharging between the batteries proceeds rapidly. To do.

  In addition, according to the vehicle equipped with the power supply device of the present invention, it is possible to prevent a decrease in output at a low temperature, and further reduce a decrease in output even when acceleration and deceleration are frequently repeated.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a case where the present invention is applied to a motor driving power supply device will be described as an example.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of a power supply apparatus according to the first embodiment of the present invention. The power supply device 100 according to the present embodiment causes the potential difference between the high-capacity battery 110 and the high-power battery 120 to be forcibly generated at a low temperature so that charging / discharging between the batteries 110 and 120 can proceed rapidly. The batteries 110 and 120 are heated.

  As shown in FIG. 1, the power supply device 100 is connected to a motor 300 via an inverter 200 for driving a motor. Inverter 200 controls charging / discharging between power supply device 100 and motor 300. When the motor is driven, the power supply device 100 and the motor 300 are electrically connected by the inverter 200, and charging / discharging is performed between the power supply device 100 and the motor 300. On the other hand, when the motor is stopped, the power supply device 100 and the motor 300 are electrically insulated.

  The power supply device 100 includes a high-capacity battery 110, a high-power battery 120, a DC-DC converter 130, a controller 140, a temperature detection device 150, and a current detection device 160.

  In the power supply device 100, a high-capacity battery 110 that is a first battery and a high-power battery 120 that is a second battery having a smaller internal resistance and capacity than the first battery include a DC-DC converter as a boosting unit. 130 are connected in parallel. Specifically, the positive electrode and the negative electrode of high-capacity battery 110 are connected to input terminals 131 and 132 of DC-DC converter 130, respectively. The positive electrode and the negative electrode of the high-power battery 120 are connected to the output terminals 133 and 134 of the DC-DC converter 130, respectively. The initial voltages of the high capacity battery 110 and the high output battery 120 are substantially the same, and both are used for discharging to the motor (load).

  The DC-DC converter 130 is a boosting unit that applies a voltage boosted by receiving the voltage of the high capacity battery 110 to the high output battery 120. The controller 140 is control means for switching between a boosting state in which the voltage is boosted by the DC-DC converter 130 and a boosting stop state in which the boosting is stopped and the high capacity battery 110 and the high output battery 120 are connected in parallel. Details of the high capacity battery 110, the high output battery 120, and the DC-DC converter 130 will be described later.

  The temperature detection device 150 is temperature detection means including temperature sensors that are independently attached to the high-capacity battery 110 and the high-power battery 120. A signal from the temperature sensor is transmitted to the controller 140. As the temperature sensor, for example, a thermocouple, a thermistor, a white resistance temperature detector, a contact sensor such as a crystal, or a non-contact sensor such as a radiation thermometer can be employed.

  The current detection device 160 is current detection means including current sensors that are independently attached to the high-capacity battery 110 and the high-power battery 120. A signal from the current sensor is transmitted to the controller 140. In addition, as a current sensor, for example, a clamp type current sensor and a Hall element type current sensor can be employed in addition to a general ammeter.

  The controller 140 receives each signal from the temperature detection device 150 and the current detection device 160, and controls the DC-DC converter 130 based on these signals.

  Next, the structure of batteries 110 and 120 in the present embodiment will be described with reference to FIG. The high-power battery 120 is a bipolar battery characterized by having a bipolar electrode. On the other hand, the high-capacity battery 110 is a conventional secondary battery (hereinafter referred to as a general battery) that is not a bipolar type. In the present embodiment, high capacity battery 110 and high power battery 120 are lithium ion secondary batteries.

  FIG. 2A is a cross-sectional view for explaining the structure of a general battery. As shown in FIG. 2A, a general battery has a basic structure in which a positive electrode in which a positive electrode active material layer 112 is formed on a metal plate 111 and a negative electrode in which a negative electrode active material layer 114 is formed on a metal plate 115. However, it has the structure laminated | stacked via the electrolyte layer 113 and accommodated in a battery case.

  When a general battery having such a configuration is used, a high capacity battery is usually obtained by connecting a plurality of batteries in series to form a battery module, and further connecting the battery modules in series to form an assembled battery. 110 is realized. However, in such an assembled battery, resistance due to the connection between the batteries and the connection between the battery modules is added, and the internal resistance of the entire assembled battery at the time of charging and discharging is increased, so that it is difficult to obtain a high output.

  On the other hand, FIG. 2B is a cross-sectional view for explaining the structure of the bipolar battery. As shown in FIG. 2B, in the bipolar battery, the bipolar electrode in which the positive electrode active material layer 122 is formed on one surface of the current collector 121 and the negative electrode active material layer 124 is formed on the other surface is the electrolyte layer 123. A plurality of layers are stacked via Since the bipolar battery has a smaller internal resistance than that of a general battery, a higher output than that of a general battery can be obtained. However, in order to improve the battery capacity using such a bipolar battery, it is necessary to increase the area of the bipolar battery, such as a vehicle in which a space in which the battery can be mounted is limited. It is disadvantageous when it is installed.

  Moreover, since both a general battery and a bipolar battery utilize a chemical reaction, they have temperature dependence. Specifically, the battery output decreases at low temperatures. Note that a detailed description of the current collector, the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer is omitted.

  Next, the DC-DC converter 130 will be described with reference to FIG. The DC-DC converter 130 itself is the same as a general DC-DC converter, and will be briefly described below.

  FIG. 3 is a circuit diagram showing an example of the configuration of the DC-DC converter 130. The DC-DC converter 130 includes, for example, a pair of input terminals 131 and 132, a pair of output terminals 133 and 134, a switching element 135, a first capacitor 136, a second capacitor 137, and a choke coil 138, as shown in FIG. And a chopper type including the first diode 141.

  A first capacitor 136 is connected between the pair of input terminals 131 and 132, and a second capacitor 137 is connected between the pair of output terminals 133 and 134. Between the input terminal 131 and the output terminal 133, the switching element 135 and the choke coil 138 are connected in series in this order. An output terminal of the first diode 141 is connected to a connection node between the switching element 135 and the choke coil 138, and an input terminal of the first diode 141 is connected to the input terminal 132 and the output terminal 134. The switching element 135 is configured by, for example, a FET (Field-Effect Transistor) 139 and a second diode 142 connected in parallel. Here, the second diode 142 is provided in a direction in which an input terminal is connected to the connection node. The switching element 135 controls the current to the choke coil 138 by switching the FET 139 ON / OFF. The first capacitor 136 and the second capacitor 137 smooth the current flowing through the choke coil 138.

  When ON / OFF of the switching element 135 is alternately switched, a boosted state in which the voltage boosted in response to the voltage of the high capacity battery 110 is applied to the high output battery 120 is obtained. On the other hand, when the OFF state of the switching element 135 is maintained, a boosting stop state is established in which the capacity battery 110 and the high-power battery 120 are connected in parallel. Switching between the boosting state and the boosting stop state is executed by the controller 140 connected to the gate terminal of the FET 139.

  The controller 140 charges and discharges between the high capacity battery 110 and the high output battery 120 by switching between the boosting state and the boost stop state when the high capacity battery 110 and the high output battery 120 are at a low temperature. The high-capacity battery 110 and the high-power battery 120 are heated.

  Next, with reference to FIG. 4, the temperature raising process for the batteries 110 and 120 in the present embodiment will be described. FIG. 4 is a flowchart showing the temperature raising process for batteries 110 and 120 in the present embodiment.

  First, the temperature detection device 150 detects the temperature of the high capacity battery 110 and sends the detected temperature data to the controller 140 (step S101). Similarly, the temperature detection device 150 detects the temperature of the high-power battery 120 and sends the detected temperature data to the controller 140 (step S102).

  Next, each temperature detected in step S101 and step S102 is compared with a predetermined temperature t1 (step S103). Here, the predetermined temperature t1 may be set in advance, or may be a predetermined value that may be appropriately set according to the outside air temperature or the temperature of the batteries 110 and 120. For example, when the outside air temperature at the start of the motor is -30 degrees, t1 is set to about -10 degrees. Further, when the outside air temperature at the time of starting the motor is −10 degrees, t1 is set to +10 degrees.

  If the detected temperatures are both equal to or higher than the predetermined temperature t1 (step S103: NO), the temperature increasing process for the batteries 110 and 120 is completed. On the other hand, if at least one of the detected temperatures is less than the predetermined temperature t1 (step S103: YES), the charging / discharging process (step S104) between the batteries is repeated until the detected temperature becomes equal to or higher than the predetermined temperature t1. It is.

  Here, the charging / discharging process (step S104) between batteries is demonstrated. FIG. 5 is a flowchart showing details of the charge / discharge process (step S104) between the batteries, which is one of the features of the present invention in the flowchart of FIG.

  First, the controller 140 switches ON / OFF of the switching element 135 alternately. As a result, the DC-DC converter 130 receives the voltage of the high-capacity battery 110 and starts a boosting process of adding the boosted voltage to the high-power battery 120 (step S201).

  FIG. 6 is a diagram illustrating changes in voltage and current of the high-capacity battery 110 and the high-power battery 120, respectively. In the figure, the horizontal axis represents time, and the vertical axis represents voltage and current values. E1 and E2 are voltages (internal voltages) of the high-capacity battery 110 and the high-power battery 120, respectively (see FIG. 3). Similarly, I1 and I2 are currents flowing into the high-capacity battery 110 and the high-power battery 120, respectively, and the direction of the arrow in FIG. 3 is positive. The initial voltages of the high capacity battery 110 and the high output battery 120 are equal to the voltage E0.

  When the boosting process (step S201) is started, the DC-DC converter 130 receives the voltage of the high capacity battery 110 and boosts the voltage. Therefore, there is a difference between the voltage boosted by the DC-DC converter 130 and the voltage E2 of the high-power battery 120. As a result, current is rapidly supplied from the DC-DC converter 130 to the high-power battery 120. At this time, since the high capacity battery 110 is discharged to the high power battery 120, the voltage E1 decreases and the current I1 flows in a negative direction. On the other hand, since the high output battery 120 is charged from the high capacity battery 110, the voltage E2 rises and the current I2 flows in the positive direction.

  Next, the current detection device 160 detects the current I2, and sends the detected current data to the controller 140 (step S202). Then, the detected absolute value of the current I2 is compared with a predetermined current value (step S203). If the absolute value of the detected current I2 is less than the predetermined current value (step S203: YES), the controller 140 proceeds to a boost stop process (step S204). On the other hand, if the detected absolute value of the current I2 is equal to or greater than the predetermined current value (step S203: NO), the processes in and after step S201 are repeatedly executed until the absolute value of the current I2 becomes less than the predetermined current value. The

  As shown in FIG. 6, when time elapses after the boosting process (step S201) is started, the potential difference between the voltage boosted by the DC-DC converter 130 and the voltage E2 of the high-power battery 120 decreases, and the current The absolute values of I1 and I2 are small. Therefore, even if the boosted state is maintained further, the charging effect on the high-power battery 120 is small, so if the absolute value of the detected current I2 is less than the predetermined current value, the process proceeds to the boost stop process. .

  Next, the DC-DC converter 130 starts a boost stop process for stopping the boost process described above (step S204). Specifically, the controller 140 maintains the switching element 135 in the OFF state. As a result, the high capacity battery 110 and the high power battery 120 are connected in parallel via the second diode 142 of the switching element 135. The boosting process is stopped by the processes in steps S202 to S204.

  When the high-capacity battery 110 and the high-power battery 120 are connected in parallel, the high-capacity battery 110 and the high-power battery 120 are arranged so that there is no potential difference between the high-capacity battery 110 and the high-power battery 120. Current flows through Specifically, the voltage E2 of the high-power battery 120 raised by the boosting process (step S201) is sufficiently larger than the voltage E1 of the high-capacity battery 110. Therefore, current is rapidly supplied from the high power battery 120 to the high capacity battery 110 through the second diode 142. As shown in FIG. 6, since the high-power battery 120 is discharged to the high-capacity battery 110, the voltage E2 decreases and the current I2 flows in the negative direction. On the other hand, since the high capacity battery 110 is charged from the high power battery 120, the voltage E1 rises and the current I1 flows in the positive direction. Therefore, the current I1 also flows through the high-capacity battery 110 where current does not easily flow at low temperatures, and the temperature of the high-capacity battery 110 rapidly increases.

  Next, the current detection device 160 detects the current I1, and sends the detected current data to the controller 140 (step S205). Then, the detected absolute value of the current I1 is compared with a predetermined current value (step S206). If the absolute value of the detected current I1 is less than the predetermined current value (step S206: YES), the controller 140 ends the boost stop process (step S204) and returns to the process of step 101 in the flowchart of FIG. . On the other hand, if the detected absolute value of the current I1 is equal to or greater than the predetermined current value (step S206: NO), the processes in and after step S204 are repeatedly executed until the absolute value of the current I1 becomes less than the predetermined current value. The

  As shown in FIG. 6, when time elapses after the boost stop processing (step S204) is started, the voltage E1 of the high-capacity battery 110 and the voltage E2 of the high-power battery 120 reach an almost equal equilibrium state, and the current I1 And the absolute value of the current I2 becomes small. Therefore, even if the boost stop state is maintained, the temperature rise effect on the high capacity battery 110 is difficult to obtain, and the boost stop state is terminated.

  As described above, in the flowcharts shown in FIG. 4 and FIG. 5, by repeatedly executing the above-described boosting state and boosting stop state, charging / discharging between the batteries 110 and 120 proceeds rapidly, and the batteries 110 and 120 rise. Be warmed. In the present embodiment, current I1 and current I2 flowing into high-capacity battery 110 and high-power battery 120 are detected in order to switch between the boosting state and the boosting stop state. However, only one of the currents to be detected may be detected.

  In the present embodiment, a case where the voltage is boosted to a certain voltage is shown. However, the boosted voltage may be changed according to the outside air temperature or the battery temperature. In this case, the boosted voltage can be changed by changing the ON / OFF switching duty ratio of the switching element 135.

  In the present embodiment, the temperatures of both the high capacity battery 110 and the high output battery 120 are detected. However, it is not always necessary to detect the temperatures of both the two batteries 110 and 120. The high-capacity battery 110 has a larger internal resistance than the high-power battery 120, so that current does not flow easily. Therefore, the high-capacity battery 110 is not easily heated. Therefore, only the temperature of the high capacity battery 110 may be detected, and when the temperature of the high capacity battery 110 is lower than a predetermined temperature, charging / discharging between the batteries 110 and 120 may be advanced.

  Next, the effect of the power supply device of this embodiment will be described.

  FIG. 7 is a diagram for explaining the battery temperature increase effect at low temperatures and the battery output improvement effect due to temperature increase by the power supply device of the present embodiment. Specifically, FIG. 7 schematically shows changes in the temperature and output voltage of the high-capacity battery 110 as time elapses after starting the motor at low temperatures. In FIG. 7, for reference, a case where a general hybrid battery as shown in FIG. 8 is used is shown as a comparative example. The dotted line in FIG. 7 represents changes in the temperature and output voltage of the high capacity battery 110 in the comparative example, and the solid line represents changes in the temperature and output voltage of the high capacity battery 110 at a low temperature in the present embodiment. ing.

  In the comparative example, current does not flow easily through the high-capacity battery 110 having a high internal resistance. Therefore, as shown in FIG. Therefore, as shown in FIG. 7B, the output voltage of the high-capacity battery 110 is low at a low temperature, and it takes time for the output voltage to improve even for the power supply device 100 as a whole.

  On the other hand, in the present embodiment, even when the motor is started, a potential difference can be forcibly generated between the two batteries 110 and 120 by the boosting means, so that charging / discharging between the two batteries 110 and 120 is possible. Progresses quickly. Accordingly, as shown in FIG. 7A, the high-capacity battery 110 can be heated in a shorter time than the comparative example. As a result, the internal resistance of the high capacity battery 110 can be lowered, and the output voltage of the high capacity battery 110 can be improved as shown in FIG. 7B. As a result, the output voltage can be improved in a shorter time even for the power supply apparatus 100 as a whole. Further, when the motor is stopped, it is possible to forcibly charge and discharge between the two batteries 110 and 120 by the action of the boosting means, and the batteries 110 and 120 can be warmed in advance.

  As described above, the described embodiment has the following effects.

  (A) A high capacity battery and a high output battery having an internal resistance and a capacity smaller than those of the high capacity battery are connected in parallel via a DC-DC converter. Therefore, a potential difference is forcibly generated between the two batteries, and charging / discharging between the two batteries can be rapidly advanced.

  (B) Also, by controlling the DC-DC converter, it is possible to switch between a boost state in which the voltage is boosted and a boost stop state in which the boost is stopped and the high capacity battery and the high output battery are connected in parallel. Therefore, charging / discharging between two batteries can be rapidly advanced. In particular, it is possible to carry out both charging / discharging (in the boosting state) in which current flows from the high-capacity battery to the high-power battery and charging / discharging (in boosting stop state) in which current flows from the high-power battery to the high-capacity battery. In the boost stop state, both the high-capacity battery and the high-power battery can be used for discharging to the motor (load), as in a general hybrid battery.

  (C) A DC-DC converter is used as the boosting means. Therefore, the voltage of the battery can be easily received and boosted.

  (D) A power supply device that effectively uses the characteristics of each of a general battery and a bipolar battery can be configured. Therefore, it is possible to realize a high-capacity and high-output power supply device that can quickly charge and discharge between batteries connected in parallel.

  (E) Charging / discharging can be rapidly advanced between the high capacity battery and the high output battery, and the battery can be heated. Furthermore, the battery output can be improved by raising the temperature of the battery.

  (F) In this embodiment, the temperature sensor is used to detect the temperature of at least one of the high capacity battery and the high output battery. Moreover, charging / discharging between batteries advances by switching a pressure | voltage rise state and a pressure | voltage rise stop state based on the detected temperature. Therefore, the battery can be heated according to the temperature of the battery.

  (G) When the detected temperature is lower than the predetermined value, the boosting state and the boosting stop state are switched. By switching between the boosting state and the boosting stop state, charging / discharging between the batteries proceeds. Therefore, the battery can be heated at a low temperature. Furthermore, the battery output at low temperature can be improved.

  (H) Further, by alternately switching the boosting state and the boosting stop state, charging / discharging between the batteries repeatedly proceeds. Therefore, the temperature of the battery can be effectively raised for a relatively long time at a low temperature. Furthermore, battery output at low temperatures can be effectively improved.

  (I) Moreover, the predetermined value of battery temperature can be set variably according to the outside air temperature or battery temperature at the time of starting the motor, and the battery can be raised without difficulty.

(Second Embodiment)
In the first embodiment, the process of heating the battery at a low temperature has been described. In the present embodiment, a process for preventing a decrease in the output of the power supply apparatus when the difference between the charge amounts of the high capacity battery and the high output battery is large will be described. Here, the state of charge (SOC) is a value indicating the ratio of the charge capacity to the rated capacity of the battery. For example, the state of full charge is 100%, and the state of charge is zero is 0%. Is displayed. From the viewpoint of preventing the output of the power supply device from decreasing, it is desirable that the difference in SOC between the high-capacity battery and the high-power battery is small. The power supply device according to the present embodiment makes the SOC uniform by rapidly charging and discharging between the batteries by forcibly generating a potential difference between the batteries when the above-described SOC difference is large. This is intended to prevent a decrease in the output of the power supply device.

  FIG. 9 is a block diagram showing a schematic configuration of a power supply device according to the second embodiment of the present invention. The power supply device 100 includes a high-capacity battery 110, a high-power battery 120, a DC-DC converter 130, a controller 140, and an SOC detection device 170. In the figure, the same reference numerals are used for the same members as those in the block diagram shown in FIG. Further, instead of the temperature detection device 150 and the current detection device 160 in the first embodiment, the SOC detection device 170 is connected, and the controller 140 is based on the signal from the SOC detection device 170 based on the DC−. Except for controlling the DC converter 130, the configuration of the power supply device 100, the inverter 200, and the motor 300 in the present embodiment is the same as that in the first embodiment, and detailed description thereof is omitted.

  The SOC detection device 170 is an SOC detection means including current sensors that are independently attached to the high-capacity battery 110 and the high-power battery 120. The SOC is a current that flows into or out of the batteries 110 and 120. Calculated by integration. In addition, since the current sensor can be shared with the current sensor of the current detection device 160 in the first embodiment, in the present embodiment, the SOC detection device 170 is replaced by the current detection device 160 in the first embodiment. It also functions.

  Next, with reference to FIG. 10, the output reduction prevention process of the power supply device in the present embodiment will be described. FIG. 10 is a flowchart showing output reduction prevention processing of the power supply device in the present embodiment.

  First, the SOC detection device 170 detects the SOC of the high-capacity battery 110, and sends the detected SOC data to the controller 140 (step S301). Similarly, SOC detection device 170 detects the SOC of high-power battery 120 and sends the detected SOC data to controller 140 (step S302). Then, the controller 140 calculates the difference between the SOCs of the high-capacity battery 110 and the high-power battery 120 detected in Steps S301 and S302 (hereinafter, SOC difference) (Step S303).

  Next, the SOC difference calculated in step S303 is compared with a predetermined SOC difference (step S304). Here, the predetermined SOC difference is a predetermined value set in advance. If the calculated SOC difference is less than the predetermined SOC difference (step S304: NO), the process ends. On the other hand, if the calculated SOC difference is greater than or equal to the predetermined SOC difference (step S304: YES), the charging / discharging process (step S305) between the batteries is performed until the calculated SOC difference becomes less than the predetermined SOC difference. Repeated. That is, while the calculated SOC difference is greater than or equal to the predetermined SOC difference, the controller 140 switches between the boosting state and the boosting stop state, thereby quickly charging / discharging between the high capacity battery 110 and the high output battery 120. Proceed to. More specifically, as shown in FIG. 6, the boosting state and the boosting stop state are repeated.

  Here, the charge / discharge process between the batteries in step S305 is the same as the charge / discharge process between the batteries in step S104 described above, and thus detailed description thereof is omitted.

  As described above, when the processing of the flowchart shown in FIG. 10 is completed, charging / discharging between the high-capacity battery 110 and the high-power battery 120 is performed even when the charge amount difference between the high-capacity battery 110 and the high-power battery 120 is large. Can proceed quickly and prevent a decrease in the output of the power supply apparatus 100.

  In the present embodiment, the case where the boosting process and the boosting stop process are repeatedly executed to repeat the boosting state and the boosting stop state is shown. However, even when the boosting process and the boosting stop process are executed only once, the output of the power supply device 100 can be prevented from being lowered.

  Further, in the present embodiment, the SOCs of high capacity battery 110 and high power battery 120 are detected, and the difference between them is calculated. However, only the SOC of the high-power battery 120 may be detected, and when the SOC is smaller than a predetermined SOC, charging / discharging between the high-capacity battery 110 and the high-power battery 120 may be advanced rapidly.

  Next, the effect of the power supply device of this embodiment will be described.

  FIG. 11 is a diagram for explaining an effect of preventing a decrease in the output of the power supply device 100 when the current of the high-power battery 120 is suddenly decreased due to the discharge to the motor 300. Specifically, FIG. 11 schematically shows a change in the output voltage of the high-power battery 120 over time. The dotted line in the figure represents the change in the output voltage of the high-power battery 120 according to the comparative example shown in FIG. 8, and the solid line represents the change in the output voltage of the high-power battery 120 according to the present embodiment. . Further, the period indicated as “discharge” in the figure is a state in which the output of the high-power battery 120 is reduced due to the discharge from the high-power battery 120 to the motor 300.

  In a state after the discharge from the high-power battery 120 to the motor 300 occurs, a potential difference is generated between the high-capacity battery 110 and the high-power battery 120. Therefore, also in the comparative example, a current is supplied from the high capacity battery 110 to the high output battery 120, and the output voltage of the high output battery 120 naturally recovers. However, compared with the present embodiment, in the comparative example, since the potential difference generated between the two batteries 110 and 120 is small, it takes time to recover the output voltage of the high-power battery 120.

  In the present embodiment, the boosting means can generate a larger potential difference between the two batteries 110 and 120 than in the comparative example, and therefore, as shown in FIG. The output voltage of the battery 120 is restored. Accordingly, even when the power supply device 100 is viewed as a whole, a decrease in output voltage is prevented.

  As described above, the described embodiment has the following effects in addition to the effects (a) to (d) in the first embodiment.

  (J) In the present embodiment, the SOC detection means is used to detect the SOC of at least one of the high capacity battery and the high output battery. Moreover, charging / discharging between batteries advances by switching a pressure | voltage rise state and a pressure | voltage rise stop state based on detected SOC. Therefore, it is possible to prevent a decrease in the output of the power supply device according to the SOC of the battery.

  (K) When the difference between the SOC of the high capacity battery and the high output battery is larger than a predetermined value, the boosting state and the boosting stop state are switched. By switching between the boosting state and the boosting stop state, charging / discharging between the batteries proceeds rapidly. Therefore, when the difference in SOC between the high-capacity battery and the high-power battery is larger than a predetermined value, it is possible to prevent the output of the power supply device from decreasing.

  (L) When the output of the high-power battery decreases due to the discharge from the high-power battery to the motor, it is possible to quickly supply current from the high-capacity battery to the high-power battery. Accordingly, it is possible to prevent the output of the high output battery from being lowered.

(Third embodiment)
In the present embodiment, fuel cells are connected in parallel to the high-capacity battery and the high-power battery of the power supply apparatus.

  FIG. 12 is a block diagram showing a schematic configuration of a power supply apparatus according to the third embodiment of the present invention. As shown in FIG. 12, the fuel cell 400 is connected in parallel to the high capacity battery 110 and the high output battery 120 of the power supply device 100. In general, a diode (not shown) or the like is attached so that current does not flow into the fuel cell 400 from the high-capacity battery 110 and the high-power battery 120. The configuration of power supply apparatus 100 in the present embodiment is the same as that in the first embodiment except that fuel cell 400 is connected in parallel to high capacity battery 110 and high output battery 120. Therefore, detailed description is omitted. In the figure, the same reference numerals are used for the same members as those in the block diagram shown in FIG.

  In the present embodiment, fuel cell 400 can supply current to motor 300 and also supply current to power supply device 100. In other words, the high capacity battery 110 and the high power battery 120 are charged from the fuel cell 400.

  Further, the output of the fuel cell 400 is likely to decrease at a low temperature, similarly to the lithium ion secondary battery. Therefore, in the present embodiment, it is desirable that the fuel cell 400, the high-capacity battery 110, and the high-power battery 120 are arranged close to each other. If it does in this way, when motor 300 starts, first, motor 300 will be driven by supply of current from high capacity battery 110 and high output battery 120. Next, as described in the first embodiment, the high-capacity battery 110 and the high-power battery 120 are heated by charging / discharging between the batteries 110 and 120 and generate heat. Therefore, the fuel cell 400 disposed in proximity to the high-capacity battery 110 and the high-power battery 120 that have been heated is heated by receiving heat from the high-capacity battery 110 and the high-power battery 120. When the temperature of the fuel cell 400 is sufficiently raised, the high capacity battery 110 and the high power battery 120 are switched to the fuel cell 400, and current is supplied from the fuel cell 400 to the motor 300. Furthermore, the high-capacity battery 110, the high-power battery 120, and the fuel cell 400 can be switched according to the situation in which the motor 300 is used.

  As described above, the described embodiment has the following effects in addition to the effects (a) to (d) in the first embodiment.

  (M) A fuel cell is connected in parallel to the high capacity battery and the high output battery. Therefore, the fuel cell can charge the high capacity battery and the high output battery.

  (N) When the high-capacity battery and the high-power battery are arranged close to the fuel cell, the temperature of the fuel cell can be raised by heat generated from the high-capacity battery and the high-power battery at low temperatures.

  (O) Furthermore, the high-capacity battery 110, the high-power battery 120, and the fuel cell can be switched alternately according to the usage status of the motor, and current can be supplied to the motor. Therefore, energy efficiency can be improved.

(Fourth embodiment)
In the first to third embodiments described above, a general battery is used as the high capacity battery 110 and a bipolar battery is used as the high output battery 120. However, the present invention is not limited to these. In the present embodiment, as shown in FIG. 13, the combination of the high capacity battery 110 and the high output battery 120 is changed. Except for the combination of batteries, the block diagram is omitted because it is the same as the first to third embodiments.

(When the thickness of the electrode active material layer is different)
The first combination is an example in which the electrode active material layer on the electrode of the high-power battery 120 is formed thinner than the electrode active material layer on the electrode of the high-capacity battery 110.

  Here, the first combination will be described with reference to FIG. First, as described above, the electrode of the lithium ion secondary battery is formed by forming the electrode active material layers (the positive electrode active material layer 112 and the negative electrode active material layer 114) on the metal plates 111 and 115, respectively. Since lithium ions are accumulated in the electrode active material layer, it is desirable that the electrode active material layer is thicker from the viewpoint of increasing the capacity of the battery. On the other hand, since the internal resistance of the battery increases as the electrode active material layer becomes thicker, it is desirable that the electrode active material layer is thinner from the viewpoint of increasing the output of the battery.

  Therefore, in the first combination, the electrode active material layer of the high power battery 120 is formed thinner than the electrode active material layer of the high capacity battery 110. The electrode materials of the high capacity battery 110 and the high power battery 120 may be the same. For example, in FIG. 13, both the high capacity battery 110 and the high output battery 120 are lithium ion secondary batteries.

(When electrode materials are different)
The second combination is an example when the electrode materials of the high-capacity battery 110 and the high-power battery 120 are different. In FIG. 13, for example, the high capacity battery 110 is a nickel metal hydride battery, and the high output battery 120 is a lithium ion battery.

  The nickel-metal hydride battery can obtain an energy density per unit volume, that is, a capacity comparable to that of a lithium ion battery, and is less expensive than a lithium ion battery. However, since the output voltage of the nickel metal hydride battery is smaller than the output voltage of the lithium ion battery, it is difficult to achieve high output. Therefore, the present invention can be implemented by effectively utilizing the characteristics of a nickel metal hydride battery capable of increasing the capacity relatively inexpensively and the characteristics of a lithium ion battery having a high output voltage and capable of increasing output. .

  As described above, the described embodiment has the following effects in addition to the effects (a) to (d) in the first embodiment.

  (P) By using a lithium ion battery, a high-output power supply device can be provided.

  (Q) When the thicknesses of the electrode active material layers are different, both the high capacity battery and the high output battery can be manufactured by making the thicknesses of the electrode active material layers different. Moreover, in the power supply apparatus of this Embodiment, it is not necessary to manufacture both a general battery and a bipolar battery. Therefore, the manufacturing process of the battery and the power supply device is simplified.

  (R) When the electrode materials are different, a high-capacity battery and a high-power battery can be manufactured even if the electrode configuration or the electrode active material layer thickness is the same. In particular, when a nickel metal hydride battery is used for the high-capacity battery and a lithium ion battery is used for the high-power battery, the manufacturing cost of the power supply device can be reduced.

(Fifth embodiment)
The present embodiment is an embodiment of a vehicle on which the power supply device of the first to fourth embodiments is mounted.

  FIG. 14 is a diagram showing a vehicle according to the present embodiment. In the present embodiment, vehicle 500 includes power supply device 100, inverter 200, and motor 300 as described in the first to fourth embodiments. In FIG. 14, for simplicity of explanation, the display of the inverter 200 and the motor 300 is omitted. A current is supplied from the power supply device 100 to the motor 300 for supplying power to the drive wheels. As a result, the driving wheel rotates and the vehicle 500 travels.

  The vehicle 500 that has been stopped for a long time in a low-temperature environment is quickly charged and discharged between the high-capacity battery 110 and the high-power battery 120 at the time of starting, so that the batteries 110 and 120 rise in a short time. It is warmed and can run stably. Further, even when acceleration and deceleration are repeated during traveling, current is rapidly supplied from the high-capacity battery 110 to the high-power battery 120, so that the output of the power supply apparatus 100 is maintained. That is, even when the acceleration state occurs frequently and the SOC of the high-power battery 120 decreases, the SOC can be quickly recovered and prepared for the next acceleration.

  As described above, the described embodiment has the following effects in addition to the effects (a) to (r) in the first to fourth embodiments.

  (S) In a vehicle equipped with the power supply device of the present invention, even when the vehicle is stopped in a low temperature environment for a long time, the temperature of the power supply device is raised in a short time when starting. Therefore, it will be in the state which can drive | work stably in a short time.

  (T) A vehicle equipped with the power supply device of the present invention repeatedly accelerates and decelerates, and even when the output of the high-power battery decreases, current is rapidly supplied from the high-capacity battery to the high-power battery. Therefore, even when the acceleration state occurs frequently, the acceleration performance does not deteriorate.

  As described above, the power supply device of the present invention has been described in the first to fifth embodiments. However, it goes without saying that the present invention can be appropriately added, modified, and omitted by those skilled in the art within the scope of the technical idea.

  For example, in this embodiment, a non-insulated chopper type DC-DC converter is used as the boosting means. However, for example, an insulation type DC-DC converter may be used as the boosting means.

  Also, the first embodiment and the second embodiment of the present invention can be executed in combination. FIG. 15 is a flowchart illustrating an example of processing in which the first embodiment and the second embodiment are combined.

  Steps S401 to S403 and S406 in FIG. 15 correspond to steps S301 to S303 and S304 in FIG. 10, respectively. Similarly, step S404, step S405, and step S407 in FIG. 15 correspond to step S101, step S102, and step S103 in FIG. 4, respectively. Further, the charge / discharge process between the batteries shown in step S408 of FIG. 15 is the process of the flowchart shown in FIG. In the process of FIG. 15, temperature data and current (SOC) data are detected in parallel. When the difference in SOC between the high-capacity battery 110 and the high-power battery 120 is large (step S406: YES), or when the temperature is low (step S407: YES), the charging / discharging process between the batteries 110 and 120 is executed.

  In addition, as another example of processing in which the first embodiment and the second embodiment are combined, the first embodiment and the second embodiment can be executed in succession. In this case, after executing the processing of the flowchart of the first embodiment shown in FIG. 4, the processing of the flowchart of the second embodiment shown in FIG. 10 may be executed, and the flowchart shown in FIG. After executing the process, the process of the flowchart shown in FIG. 4 may be executed.

It is a block diagram which shows schematic structure of the power supply device which is the 1st Embodiment of this invention. It is sectional drawing for demonstrating the structure of the general battery and bipolar battery which are shown by FIG. It is a circuit diagram which shows an example of a structure of the DC-DC converter shown by FIG. It is a flowchart which shows the temperature rising process of the battery in the power supply device shown by FIG. It is a flowchart which shows the charging / discharging process between the batteries shown by FIG.4 S104. It is a figure which shows the change of the voltage and electric current of the high capacity | capacitance battery shown in FIG. 1, and a high output battery. It is a figure for demonstrating the effect by the power supply device shown by FIG. It is a block diagram which shows a general hybrid battery as a comparative example of the power supply device shown by FIG. It is a block diagram which shows schematic structure of the power supply device which is the 2nd Embodiment of this invention. It is a flowchart which shows the output fall prevention process of the battery in the power supply device shown by FIG. It is a figure for demonstrating the effect by the power supply device shown by FIG. It is a block diagram which shows schematic structure of the power supply device which is the 3rd Embodiment of this invention. It is a figure which shows the example of the combination of the high capacity battery and the high output battery in the power supply device which is the 4th Embodiment of this invention. It is a figure which shows the vehicle which is the 5th Embodiment of this invention. It is a flowchart which shows an example of the process which advances the charging / discharging between batteries combining the process of the flowchart shown by FIG. 4 and FIG.

Explanation of symbols

100 power supply,
110 high capacity battery (first battery),
120 high power battery (second battery),
130 DC-DC converter (boosting means),
140 controller (control means),
150 temperature detection device (temperature detection means),
160 current detection device,
170 SOC detection device (charge amount detection means),
200 inverter,
300 motor,
400 fuel cell,
500 vehicles.

Claims (14)

  Boosting means for applying, to the second battery, a voltage boosted by the first battery and a second battery having a smaller internal resistance and capacity than the first battery by receiving the voltage of the first battery. And a power supply device connected in parallel.   2. The control unit according to claim 1, further comprising a control unit that switches between a boosting state in which the voltage is boosted by the boosting unit and a boosting stop state in which the boosting is stopped and the first and second batteries are connected in parallel. Power supply. Temperature detecting means for detecting the temperature of at least one of the first and second batteries;
The power supply apparatus according to claim 1, wherein the control unit switches between the boosting state and the boosting stop state based on a temperature detected by the temperature detecting unit.   The said control means switches the said pressure | voltage rise state and the said pressure | voltage rise stop state, when the temperature of the said 1st or 2nd battery which the said temperature detection means detects is lower than predetermined value. The power supply described.   The power supply apparatus according to claim 4, wherein the control unit alternately switches between the boosting state and the boosting stop state. Charge amount detecting means for detecting a charge amount of at least one of the first and second batteries;
The power supply apparatus according to claim 1, wherein the control unit switches between the boosting state and the boosting stop state based on a charge amount detected by the charge amount detection unit.   The control unit switches between the boosting state and the boosting stop state when a difference between the charging amounts of the first and second batteries detected by the charging amount detection unit is larger than a predetermined value. The power supply device according to claim 6. The first battery is a general battery in which a positive electrode in which a positive electrode active material layer is formed and a negative electrode in which a negative electrode active material layer is formed are stacked via an electrolyte layer,
The second battery is a bipolar battery in which a plurality of bipolar electrodes each having a positive electrode active material layer formed on one surface of a current collector and a negative electrode active material layer formed on the other surface are disposed via an electrolyte layer. The power supply device according to claim 1, wherein the power supply device is a battery.   2. The power supply device according to claim 1, wherein an electrode active material layer on an electrode of the second battery is formed thinner than the first battery.   The power supply device according to claim 8, wherein the first and second batteries are lithium ion batteries.   2. The power supply device according to claim 1, wherein the first battery is a nickel metal hydride battery, and the second battery is a lithium ion battery.   The power supply apparatus according to claim 1, further comprising a fuel cell connected in parallel to the first and second batteries.   The power supply apparatus according to claim 1, wherein the boosting unit is a DC-DC converter.   A vehicle equipped with the power supply device according to any one of claims 1 to 13.

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