JP2020156119A - Management device and electrical power system - Google Patents

Abstract

To sufficiently utilize capacity of a cell even when a trouble occurs in a portion of a voltage detection system.SOLUTION: In a management device (30), a voltage detection circuit (31) detects each voltage of a plurality of cells (S1 to S8) connected in series. A plurality of discharge circuits (R11 to R18, Q1 to Q8) are respectively connected in parallel with the plurality of cells (S1 to S8). A controller (32) controls the plurality of discharge circuits (R11 to R18, Q1 to Q8) based on a voltage detected by the voltage detection circuit (31) and performs equalization control. The controller (32) can select a first mode in which chargeable actual capacities of the plurality of cells (S1 to S8) are aligned based on current full charge capacity and the detection voltage of each of the plurality of cells (S1 to S8) and a second mode in which dischargeable actual capacities of the plurality of cells (S1 to S8) are aligned based on current full charge capacity and the detection voltage of each of the plurality of cells (S1 to S8).SELECTED DRAWING: Figure 1

Description

The present invention relates to a management device for managing the state of a power storage module and a power supply system.

In recent years, hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), and electric vehicles (EVs) have become widespread. These cars are equipped with a secondary battery as a key device. Nickel-metal hydride batteries and lithium-ion batteries are mainly used as in-vehicle secondary batteries. It is expected that the spread of lithium-ion batteries with high energy density will accelerate in the future.

Lithium-ion batteries require stricter voltage control than other types of batteries because the normal area and the prohibited area are close to each other. When using an assembled battery in which a plurality of lithium ion battery cells are connected in series, a voltage detection circuit for detecting the voltage of each cell is provided. Each node of a plurality of cells and a voltage detection circuit are connected by a plurality of voltage detection lines. The detected cell voltage is used for SOC (State Of Charge) management, equalization control, and the like (see, for example, Patent Document 1).

In general equalization control, by discharging a minute current from a cell having a high SOC (= high voltage) among a plurality of cells, each SOC of the plurality of cells is controlled to be kept substantially equal. At that time, discharge control of a plurality of cells is often performed so that the SOCs of the plurality of cells are aligned.

Japanese Unexamined Patent Publication No. 2011-41422

However, in the equalization control that combines the SOCs of multiple cells, if the voltage of some cells cannot be detected due to a defect in the voltage detection circuit or the voltage detection line, the SOC is moved away from the upper and lower limits as much as possible. It needs to be aligned. In addition, since cells with a malfunction in the voltage detection system cannot detect over-discharge and over-charge, it is necessary to stop the discharge with a large margin so as not to cause over-discharge during discharge, and over-charge during charging. It is necessary to stop charging with a large margin so as not to generate. That is, the capacity of the cell cannot be fully utilized.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique capable of fully utilizing the capacity of a cell even if a defect occurs in a part of the voltage detection system.

In order to solve the above problems, the management device of one embodiment of the present invention includes a voltage detection circuit that detects the voltage of each of a plurality of cells connected in series, and a plurality of cells connected in parallel to the plurality of cells. The discharge circuit is provided with a control unit that controls the plurality of discharge circuits and executes equalization control based on the voltage detected by the voltage detection circuit. The control unit has a first mode in which the actual chargeable capacities of the plurality of cells are arranged based on the current full charge capacity and the detection voltage of each of the plurality of cells, and the current current capacity of each of the plurality of cells. It is possible to select a second mode in which the actual dischargeable capacities of the plurality of cells are aligned based on the fully charged capacity and the detected voltage.

It should be noted that any combination of the above components and the conversion of the expression of the present invention between methods, devices, systems and the like are also effective as aspects of the present invention.

According to the present invention, even if a defect occurs in a part of the voltage detection system, the capacity of the cell can be fully utilized.

It is a figure which shows the power-source system which concerns on embodiment of this invention. 2A and 2B are diagrams for explaining a method of combining SOCs of a plurality of cells in equalization control. 3A and 3B are diagrams for explaining a method of matching the chargeable amounts of a plurality of cells in equalization control. 4 (a) and 4 (b) are diagrams for explaining a method of matching the dischargeable amounts of a plurality of cells in equalization control. It is a figure for demonstrating the vehicle equipped with the power-source system which concerns on embodiment of this invention.

FIG. 1 is a diagram showing a power supply system 1 according to an embodiment of the present invention. The power supply system 1 includes a power storage module 10 and a management device 30. The power storage module 10 includes a plurality of cells connected in series. As the cell, a lithium ion battery cell, a nickel hydrogen battery cell, a lead battery cell, an electric double layer capacitor cell, a lithium ion capacitor cell, or the like can be used. Hereinafter, in the present specification, an example in which a lithium ion battery cell (nominal voltage: 3.6-3.7 V) is used is assumed. FIG. 1 depicts an example of using an assembled battery in which eight lithium ion battery cells (cells S1-S8) are connected in series.

The management device 30 includes an equalization circuit, an input filter, a cell voltage detection circuit 31 and a control circuit 32, which are mounted on a printed wiring board. The cell voltage detection circuit 31 is connected to each node of a plurality of cells S1-S8 connected in series by a plurality of voltage detection lines L1-L9, detects a voltage between adjacent voltage detection lines, and detects each cell S1-S8. Detect the voltage of. The cell voltage detection circuit 31 is composed of, for example, an ASIC (Application Specific Integrated Circuit) which is a dedicated custom IC. The cell voltage detection circuit 31 transmits the detected voltage of each cell S1-S8 to the control circuit 32.

A wire harness is connected to each node of the plurality of cells S1-S8 of the power storage module 10, and a connector at the tip of each wire harness is attached to each connector of the management device 30 mounted on the printed wiring board. That is, the power storage module 10 and the management device 30 are electrically connected via the harness connector 20.

Resistors R1-R9 are inserted into each of the plurality of voltage detection lines L1-L9, and capacitors C1-C8 are connected between the two adjacent voltage detection lines, respectively. The resistors R1-R9 and the capacitors C1-C8 form an input filter (low-pass filter) and have an action of stabilizing the voltage input to the cell voltage detection circuit 31.

Each connector of the management device 30 and each detection terminal of the cell voltage detection circuit 31 are connected by a plurality of voltage detection lines L1-L9. An equalization circuit is connected between two adjacent voltage detection lines. In the example shown in FIG. 1, the equalization circuit is composed of a series circuit of the discharge resistors R11-R18 and the discharge switches Q1-Q8. The discharge switches Q1-Q8 are composed of, for example, transistors.

Although not shown in FIG. 1, a current sensor for detecting the value of the current flowing through the plurality of cells S1-S8 is installed. For example, a Hall element or a shunt resistor can be used for the current sensor. Further, at least one temperature sensor for detecting the temperature of the plurality of cells S1-S8 is installed. For example, a thermistor can be used as the temperature sensor. The detected values of the current sensor and the temperature sensor are output to the control circuit 32.

The control circuit 32 includes voltage values of the plurality of cells S1-S8 acquired from the cell voltage detection circuit 31, current values of the plurality of cells S1-S8 acquired from the current sensor, and plurality of cells S1-S8 acquired from the temperature sensor. A plurality of cells S1-S8 are managed based on the temperature value. The control circuit 32 estimates SOC and SOH (State Of Health) of a plurality of cells S1-S8. The SOC can be estimated by, for example, the OCV (Open Circuit Voltage) method or the current integration method.

SOH is defined by the ratio of the current full charge capacity to the initial full charge capacity, and the lower the value (closer to 0%), the more the deterioration progresses. SOH can be estimated based on the correlation with the internal resistance. The internal resistance can be estimated by dividing the voltage drop that occurs when a predetermined current is passed through the battery for a predetermined time by the current. The internal resistance is related to decrease as the temperature rises, and increases as the deterioration of the battery progresses. The deterioration of the battery progresses as the number of times of charging and discharging increases. In addition, battery deterioration depends on individual differences and the usage environment. Therefore, as the usage period becomes longer, the capacity variation of the plurality of cells S1-S8 basically increases.

The capacity of the plurality of cells S1-S8 varies not only due to factors due to deterioration over time but also due to factors in the current usage environment. For example, when there is a difference in temperature between the plurality of cells S1-S8 depending on the installation position of the plurality of cells S1-S8, the capacity varies. On the other hand, the control circuit 32 executes equalization control between the plurality of cells S1-S8. In the equalization control by discharge, the capacity of the other cell is adjusted to the cell having the smallest capacity among the plurality of cells S1-S8. At that time, there are a plurality of methods for adjusting the capacity.

2A and 2B are diagrams for explaining a method of combining SOCs of a plurality of cells in equalization control. Hereinafter, in order to simplify the drawing, a case where the number of cells in series is four will be described as an example. FIG. 2A shows the storage capacity of the plurality of cells S1-S4 before equalization, and FIG. 2B shows the storage capacity of the plurality of cells S1-S4 after equalization. The width of each bar indicates the current full charge capacity (deterioration degree) of each cell, and the area of each bar indicates the capacity of each cell. The control circuit 32 estimates the SOCs of the plurality of cells S1-S4, respectively, and puts the cell having the lowest SOC (cell S1 in FIG. 2A) into another cell (cells S2-S4 in FIG. 2A). Control to match the SOC. The control circuit 32 turns on the discharge switch Q2-Q4 of the equalization circuit connected in parallel with the other cells S2-S4 to discharge the other cells S2-S4. When the SOC of the other cells S2-S4 drops to the voltage of the cell S1 having the lowest SOC, the discharge switch Q2-Q4 of the equalization circuit connected in parallel with the other cells S2-S4 is turned off. The SOC can be estimated by OCV or current integration as described above.

3A and 3B are diagrams for explaining a method of matching the chargeable amounts of a plurality of cells in equalization control. FIG. 3A shows the storage capacity of the plurality of cells S1-S4 before equalization, and FIG. 3B shows the storage capacity of the plurality of cells S1-S4 after equalization. The length of each bar indicates the current full charge capacity (deterioration degree) of each cell. The chargeable amount of the cell is defined by the actual capacity (Ah) that can be charged to the cell. The control circuit 32 estimates the rechargeable amount of each of the plurality of cells S1-S4, and puts the cell having the largest rechargeable amount (cell S1 in FIG. 3A) into another cell (cell S2 in FIG. 3A). -S4) is controlled so as to match the chargeable amount. The control circuit 32 turns on the discharge switch Q2-Q4 of the equalization circuit connected in parallel with the other cells S2-S4 to discharge the other cells S2-S4. When the chargeable amount of the other cells S2-S4 increases to the chargeable amount of the cell S1 having the largest chargeable amount, the discharge switch Q2 of the equalization circuit connected in parallel with the other cells S2-S4 -Turn off Q4.

The control circuit 32 can estimate the chargeable amount of the cell based on the current full charge capacity and the detection voltage of the cell. The current full charge capacity can be estimated based on the SOH of the cell and the life curve that defines the relationship between the full charge capacity and SOH. The full charge capacity of the cell decreases from BOL (Begining Of Life) to EOL (End Of Life). The control circuit 32 can convert the SOH (%) into the actual capacity (Ah) of the current full charge capacity by applying the SOH estimated based on the internal resistance or the like to the life curve. Further, the control circuit 32 applies the SOC (%) estimated based on the detected voltage of the cell to the actual capacity (Ah) of the current fully charged capacity, so that the SOC (%) is the actual capacity of the current storage capacity. It can be converted to (Ah). The control circuit 32 can estimate the chargeable amount (Ah) by subtracting the estimated current actual storage capacity (Ah) from the estimated current actual capacity (Ah) of the fully charged capacity.

4 (a) and 4 (b) are diagrams for explaining a method of matching the dischargeable amounts of a plurality of cells in equalization control. FIG. 4A shows the storage capacity of the plurality of cells S1-S4 before equalization, and FIG. 4B shows the storage capacity of the plurality of cells S1-S4 after equalization. The length of each bar indicates the current full charge capacity (deterioration degree) of each cell. The dischargeable amount of the cell is defined by the actual capacity (Ah) that can be discharged from the cell. The control circuit 32 estimates the dischargeable amounts of the plurality of cells S1-S4, respectively, and puts the cell with the smallest dischargeable amount (cell S1 in FIG. 4A) into another cell (cell S2 in FIG. 4A). -S4) is controlled so as to match the dischargeable amount. The control circuit 32 turns on the discharge switch Q2-Q4 of the equalization circuit connected in parallel with the other cells S2-S4 to discharge the other cells S2-S4. When the dischargeable amount of the other cells S2-S4 decreases to the dischargeable amount of the cell S1 having the smallest dischargeable amount, the discharge switch Q2 of the equalization circuit connected in parallel with the other cells S2-S4 -Turn off Q4.

The control circuit 32 can estimate the dischargeable amount of the cell based on the current full charge capacity of the cell and the detected voltage. The control circuit 32 estimates the actual capacity (Ah) of the current storage capacity of the cell by the above-mentioned method, and sets it as the dischargeable amount (Ah) of the cell.

When the full charge capacity of the plurality of cells S1-S4 varies, in the mode of matching the SOCs of the plurality of cells S1-S4 shown in FIG. 2B (hereinafter referred to as the SOC matching mode), the plurality of cells S1- The chargeable amount and the dischargeable amount of S4 also vary. In the mode in which the chargeable amounts of the plurality of cells S1-S4 shown in FIG. 3B are combined (hereinafter referred to as the charge matching mode), the chargeable amounts of the plurality of cells S1-S4 are the same, but the dischargeable amounts vary. In the mode in which the dischargeable amounts of the plurality of cells S1-S4 shown in FIG. 4B are combined (hereinafter referred to as the discharge matching mode), the dischargeable amounts of the plurality of cells S1-S4 are the same, but the chargeable amount varies.

In the circuit configuration shown in FIG. 1, a problem may occur in a part of the voltage detection system due to deterioration over time, vibration, or the like, and the voltage of some cells of the plurality of cells S1-S8 may not be detected. For example, if the voltage detection line is broken or the element such as a resistor is peeled off from the substrate, the voltage of some cells cannot be detected. In this embodiment, the state in which all the voltages of the plurality of cells S1-S8 cannot be detected is not targeted. It is assumed that the voltage of at least one cell is in a detectable state.

If the voltage of one cell of the plurality of cells equalized in the SOC matching mode cannot be detected, the over-discharge and over-charge of the cell cannot be detected with high accuracy. For example, when the voltage of the cell S2 in FIG. 2B cannot be detected, if the over-discharge determination of the cell S2 is performed based on the lower limit SOC of the adjacent cell S1, the cell S2 enters the over-discharge region. It cannot be stopped. Further, if the overcharge determination of the cell S2 is performed based on the upper limit SOC of the adjacent cell S1, it is not possible to prevent the cell S2 from entering the overcharge region.

If the voltage of one cell of the plurality of cells equalized in the charge matching mode cannot be detected, the over-discharge of the cell cannot be detected with high accuracy. For example, when the voltage of the cell S2 in FIG. 3B cannot be detected, the over-discharge determination of the cell S2 is performed based on the lower limit of the SOC of the adjacent cell S1, and the cell S2 enters the over-discharge region. Cannot be stopped. On the other hand, if the overcharge determination of the cell S2 is performed based on the upper limit of the actual capacity (Ah) of the adjacent cell S1, it is possible to prevent the cell S2 from entering the overcharge region. In FIG. 3B, since the chargeable amounts of the plurality of cells S1-S4 are the same, if the voltage of at least one cell can be detected, all the cells S1-S4 can be charged at the appropriate actual capacity (Ah) position. Can be stopped with.

If the voltage of one cell of the plurality of cells equalized in the discharge matching mode cannot be detected, the overcharge of the cell cannot be detected with high accuracy. For example, when the voltage of the cell S2 in FIG. 4B cannot be detected and the overcharge determination of the cell S2 is performed based on the upper limit of the SOC of the adjacent cell S1, the cell S1 enters the overcharge area. Cannot be stopped. On the other hand, if the over-discharge determination of the cell S2 is performed with reference to the lower limit of the actual capacity (Ah) of the adjacent cell S1, it is possible to prevent the cell S2 from entering the over-discharge region. In FIG. 4B, since the dischargeable amounts of the plurality of cells S1-S4 are uniform, if the voltage of at least one cell can be detected, the discharge of all the cells S1-S4 can be performed at an appropriate actual capacity (Ah) position. Can be stopped with.

Based on the above, in the present embodiment, the control circuit 32 properly uses the charge matching mode and the discharge matching mode when performing equalization control. Equalization control is generally performed while charging / discharging is stopped. The control circuit 32 selects the charge matching mode when the operation of the power storage module 10 after the completion of equalization is charging. Since the chargeable amount is equalized at the end of equalization, even if a problem occurs in a part of the voltage detection system during the subsequent charging of the power storage module 10, the detection value of the voltage detection system in which the problem does not occur. By using, all cells S1-S8 can be charged to the upper limit of the actual capacity (Ah) without causing overcharging.

On the other hand, the control circuit 32 selects the discharge matching mode when the operation of the power storage module 10 after the completion of equalization is discharge. Since the dischargeable amount becomes uniform at the end of equalization, even if a problem occurs in a part of the voltage detection system during the subsequent discharge of the power storage module 10, the detection value of the voltage detection system in which the problem does not occur. By using the above, all cells S1-S8 can be discharged to the lower limit of the actual capacity (Ah) without causing over-discharging.

The equalization control can also be performed during charging / discharging of the power storage module 10. The control circuit 32 selects the charge matching mode in the equalization control during charging of the power storage module 10. The storage capacities of all cells S1-S8 are fully charged at the same timing. On the other hand, the control circuit 32 selects the discharge matching mode in the equalization control during discharge of the power storage module 10. The storage capacities of all cells S1-S8 become zero at the same timing.

FIG. 5 is a diagram for explaining a vehicle 2 equipped with a power supply system 1 according to an embodiment of the present invention. In the present embodiment, an electric vehicle (EV) that can be charged from a commercial power system (hereinafter, simply referred to as system 3) is assumed as the vehicle 1.

The vehicle 2 includes a power supply system 1, an inverter 40, a motor 50, a charging unit 60, a first relay RY1 and a second relay RY2. As described above, the power supply system 1 includes a power storage module 10, a harness connector 20, and a management device 30.

The inverter 40 converts the DC power supplied from the power storage module 10 into AC power and supplies it to the motor 50 during power running. At the time of regeneration, the AC power supplied from the motor 50 is converted into DC power and supplied to the power storage module 10. During power running, the motor 50 rotates according to the AC power supplied from the inverter 40. At the time of regeneration, the rotational energy due to deceleration is converted into AC power and supplied to the inverter 40.

The first relay RY1 is inserted between the wiring connecting the power storage module 10 and the inverter 40. The management device 30 controls the first relay RY1 to be in the ON state (closed state) during traveling, and electrically connects the power storage module 10 and the power system. In principle, the management device 30 controls the first relay RY1 to an off state (open state) when the vehicle is not running, and electrically shuts off the power storage module 10 and the power system.

The power storage module 10 can be charged from the charging device 4 installed outside the vehicle 2. The charging device 4 and the vehicle 2 are connected by a charging cable 5. In the vehicle 2, the power supply line connected to the charging cable 5 is connected to the charging unit 60. The charging unit 60 is connected to the power storage module 10 via the second relay RY2, and charges the power storage module 10 with the electric power supplied from the charging device 4. When the management device 30 detects an overvoltage, undervoltage, overcurrent, or temperature abnormality of the power storage module 10, it turns off the first relay RY1 and the second relay RY2 to protect the power storage module 10.

The charging device 4 is installed in homes, car dealers, service areas, commercial facilities, public facilities, and the like. The charging device 4 is connected to the system 3 and supplies AC100 / 200V single-phase AC power to the vehicle 2 via the charging cable 5. If the general power storage module 10 is charged with a current of 15 A or more, the power storage module 10 can be fully charged within several hours. When charging with a current of 7 A or less, it takes 12 hours or more to fully charge. When charging with AC100V at a low current, the plug of the charging cable 5 may be directly inserted into a household outlet without providing the charging device 4.

When a problem occurs in a part of the voltage detection system of the power storage module 10, the principle countermeasure is to stop the vehicle 2 and stop the power supply system 1. However, in the case of a pure electric vehicle not equipped with an internal combustion engine, if the power supply system 1 is stopped, it cannot run on its own. Since the malfunction of the voltage detection system is not the malfunction of the cell itself, there is a strong demand for limited self-propelling in order to move to a car dealer or a repair shop. As shown in FIG. 4B, when the dischargeable amounts of a plurality of cells are the same, even if there is a cell whose voltage cannot be detected, over-discharge is performed based on the detected voltage of other cells. Can be suppressed. Therefore, it is permissible to use the current storage capacity as electric power for traveling. If a problem occurs in a part of the voltage detection system, a battery error will be displayed on the instrument panel in front of the driver's seat.

The control circuit 32 of the management device 30 periodically executes equalization control of a plurality of cells S1-S8 in the power storage module 10. When the power storage module 10 in the vehicle 2 is being charged from the charging device 4, the control circuit 32 performs equalization control in the charge matching mode. Further, when the vehicle 2 is traveling by the motor 50, the control circuit 32 performs equalization control in the discharge matching mode. Since the regenerative power is very small and the amounts charged to the plurality of cells S1-S8 are the same, the regenerative power is ignored in the equalization control.

When the vehicle 2 is parked, the control circuit 32 uses different modes depending on whether the next state of the vehicle 2 is "charging" or "running". When the next state of the vehicle 2 is "charging", the control circuit 32 performs equalization control in the charge matching mode. When the next state of the vehicle 2 is "running", the control circuit 32 performs equalization control in the discharge matching mode. The control circuit 32 predicts the next state of the vehicle 2 by referring to at least one of the traveling history, the charging history, the current time, and the remaining capacity of the power storage module 10 of the vehicle 2.

For example, when the vehicle travels less at night, is often charged from the household charging device 4 at night, and the time is at night, the control circuit 32 predicts the next state of the vehicle 2 as "charging" and charges the vehicle 2. Equalization control is performed in the alignment mode. Further, when the remaining capacity of the power storage module 10 is 100%, the control circuit 32 predicts that the next state of the vehicle 2 is "running" and performs equalization control in the discharge matching mode. When the remaining capacity of the power storage module 10 is less than 5%, the next state of the vehicle 2 is predicted to be "charged", and equalization control is performed in the charge matching mode.

When a problem occurs in a part of the voltage detection system during the equalization control in the charge matching mode, the control circuit 32 completes the equalization control and also completes the next "charging". The control circuit 32 allows the "running" following the "charging" after setting a voltage having a margin to the normal discharge end voltage as the discharge end voltage. That is, the discharge is terminated at a voltage higher than the normal discharge termination voltage. Since the dischargeable amount is not uniform, a margin is provided so that the cell whose voltage cannot be detected does not over-discharge. Note that "charging" following "running" is prohibited unless the problem with the voltage detection system is resolved.

If a problem occurs in a part of the voltage detection system during "charging" after "charging" is started from the state where the equalization control in the charge matching mode is completed and the chargeable amount is complete, the control circuit 32 Completes "charging". The control circuit 32 allows the "running" following the "charging" after setting a voltage having a margin to the normal discharge end voltage as the discharge end voltage. Note that "charging" following "running" is prohibited unless the problem with the voltage detection system is resolved.

When a problem occurs in a part of the voltage detection system during the equalization control in the discharge matching mode, the control circuit 32 completes the equalization control and also completes the next "running". Since the control circuit 32 has the same dischargeable amount in the "running", it allows discharge up to the normal discharge end voltage. It should be noted that the discharge end voltage may have a margin with an emphasis on safety. Note that "charging" following "running" is prohibited unless the problem with the voltage detection system is resolved.

If a problem occurs in a part of the voltage detection system during "running" after "running" is started from the state where the equalization control in the discharge matching mode is completed and the dischargeable amount is complete, the control circuit 32 Completes the "running". Since the control circuit 32 has the same dischargeable amount in the "running", it allows discharge up to the normal discharge end voltage. It should be noted that the discharge end voltage may have a margin with an emphasis on safety. Note that "charging" following "running" is prohibited unless the problem with the voltage detection system is resolved. With the above control, even if a problem occurs in a part of the voltage detection system, it can be moved to a card dealer or a repair shop by itself.

As described above, according to the present embodiment, by appropriately using the charge matching mode and the discharge matching mode, even if a problem occurs in a part of the voltage detection system, a plurality of modes are not over-discharged or over-charged. The cells S1-S8 of the above can be fully utilized. That is, before charging, the chargeable amounts of the plurality of cells S1-S8 are matched by equalizing control in the charge matching mode. As a result, all cells S1-S8 can be charged to the full charge capacity even if a problem occurs in a part of the voltage detection system. On the other hand, before discharging, the dischargeable amounts of the plurality of cells S1-S8 are matched by equalizing control in the discharge matching mode. As a result, all cells S1-S8 can be discharged to the discharge end capacity even if a problem occurs in a part of the voltage detection system.

The present invention has been described above based on the embodiments. It will be understood by those skilled in the art that these embodiments are examples, and that various modifications are possible for each of the components and combinations of each processing process, and that such modifications are also within the scope of the present invention. is there.

In FIG. 5, an example in which the power supply system 1 according to the present embodiment is applied to a pure electric vehicle (EV) has been described, but it can also be applied to a plug-in hybrid vehicle (PHEV). However, batteries mounted on hybrid vehicles tend to have a narrower SOC usage range than batteries mounted on EVs. Therefore, the risk of over-discharging or over-charging is small even if equalization control is performed in the SOC matching mode. Further, when a problem occurs in a part of the voltage detection system as described above, even if the power supply system 1 is stopped, the engine can be moved to the car dealer or the repair shop. Conversely, it means that there is a great merit of using the power supply system 1 according to the present embodiment for a pure electric vehicle.

Further, in the above-described embodiment, an example in which the power supply system 1 is used as a power supply device for a vehicle is assumed, but it is not limited to in-vehicle use, but is used for other uses such as an aviation power supply device, a ship power supply device, and a stationary power storage system. Is also available.

In addition, the embodiment may be specified by the following items.

[Item 1]
A voltage detection circuit (31) that detects the voltage of each of a plurality of cells (S1-S8) connected in series, and
A plurality of discharge circuits (R11-R18, Q1-Q8) connected in parallel to the plurality of cells (S1-S8), respectively.
A control unit (32) that controls the plurality of discharge circuits (R11-R18, Q1-Q8) to execute equalization control based on the voltage detected by the voltage detection circuit (31) is provided. ,
The control unit (32) arranges the actual chargeable capacities of the plurality of cells (S1-S8) based on the current full charge capacity and the detection voltage of each of the plurality of cells (S1-S8). Select one mode and the second mode in which the actual dischargeable capacities of the plurality of cells (S1-S8) are aligned based on the current full charge capacity and the detection voltage of each of the plurality of cells (S1-S8). A management device (30) characterized in that it is possible.
According to this, the first mode and the second mode can be appropriately used depending on the situation where it is necessary to prevent overcharging and the situation where it is necessary to prevent overdischarging.
[Item 2]
The control unit (32) executes equalization control in the first mode before or during charging of the plurality of cells (S1-S8), and before or during discharge of the plurality of cells (S1-S8). The management device (30) according to item 1, wherein the equalization control is executed in the second mode.
According to this, it is possible to prevent overcharging of some cells by aligning the chargeable amount before or during charging, and by aligning the dischargeable amount before or during discharging, some cells. It is possible to suppress the occurrence of over-discharge.
[Item 3]
The control unit (32) may use the plurality of cells (S1-S8) even if a problem occurs in a part of the voltage detection system during charging of the plurality of cells (S1-S8) after equalization control in the first mode. The management device (30) according to item 1 or 2, wherein charging of the cells (S1-S8) is continued.
According to this, since the chargeable amounts of the plurality of cells (S1-S8) are uniform, the plurality of cells (S1-S8) do not overcharge even if the charging is continued. Can be charged.
[Item 4]
The control unit (32) has the plurality of cells (S1-S8) even if a problem occurs in a part of the voltage detection system during discharging of the plurality of cells (S1-S8) after equalization control in the second mode. The management device (30) according to item 1 or 2, wherein the discharge of the cells (S1-S8) is continued.
According to this, since the dischargeable amounts of the plurality of cells (S1-S8) are uniform, the plurality of cells (S1-S8) do not over-discharge even if the discharge is continued. Can be discharged.
[Item 5]
A power storage module (10) in which a plurality of cells (S1-S8) are connected in series, and
The management device (30) according to any one of items 1 to 4 for managing the power storage module (10).
A power supply system (1), which comprises.
According to this, it is possible to construct a power supply system (1) capable of appropriately using the first mode and the second mode depending on the situation where it is necessary to prevent overcharging and the situation where it is necessary to prevent overdischarging. ..
[Item 5]
The power supply system (1) is mounted on the vehicle (2).
Item 5 is characterized in that the control (32) unit executes equalization control in the first mode before or during charging of the power storage module (10) from the external charging device (4). The power supply system (1) described.
According to this, it is possible to suppress the occurrence of overcharging in some cells by adjusting the chargeable amount before or during charging from the charging device (4).
[Item 6]
The power supply system (1) is mounted on the vehicle (2).
The power storage module (10) supplies electric power to the traveling motor (50) in the vehicle (2).
The power supply system according to item 5, wherein the control unit (32) executes equalization control in the second mode before or during traveling by the traveling motor (50). 1).
According to this, it is possible to suppress the occurrence of over-discharging in some cells by adjusting the dischargeable amount before or during the running.

1 Power supply system, 10 Power storage module, S1, S2, S3, S4, S5, S6, S7, S8 cell, L1, L2, L3, L4, L5, L6, L7, L8, L9 Voltage detection line, 20 Harness connector , 30 Management device, R1, R2, R3, R4, R5, R6, R7, R8, R9 resistor, C1, C2, C3, C4, C5, C6, C7, C8 capacitor, R11, R12, R13, R14, R15 , R16, R17, R18 Discharge resistance, Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8 Discharge switch, 31 cell voltage detection circuit, 32 control circuit, 2 vehicles, 3 systems, 4 charging devices, 5 charging cables , 40 Inverter, 50 Motor, 60 Charging unit, RY1 1st relay, RY2 2nd relay.

Claims (7)

A voltage detection circuit that detects the voltage of each of multiple cells connected in series,
A plurality of discharge circuits connected in parallel to the plurality of cells,
A control unit that controls the plurality of discharge circuits to execute equalization control based on the voltage detected by the voltage detection circuit is provided.
The control unit has a first mode in which the actual chargeable capacities of the plurality of cells are arranged based on the current full charge capacity and the detection voltage of each of the plurality of cells, and the current current capacity of each of the plurality of cells. A management device characterized in that a second mode in which the actual dischargeable capacities of the plurality of cells are aligned can be selected based on the fully charged capacity and the detected voltage. The control unit executes equalization control in the first mode before or during charging of the plurality of cells, and executes equalization control in the second mode before or during discharging of the plurality of cells. The management device according to claim 1. The control unit continues to charge the plurality of cells even if a problem occurs in a part of the voltage detection system during charging of the plurality of cells after equalization control in the first mode. The management device according to claim 1 or 2. The control unit continues to discharge the plurality of cells even if a problem occurs in a part of the voltage detection system during the discharge of the plurality of cells after the equalization control in the second mode. The management device according to claim 1 or 2. A power storage module in which multiple cells are connected in series,
The management device according to any one of claims 1 to 4, which manages the power storage module.
A power supply system characterized by being equipped with. The power supply system is mounted on the vehicle and
The power supply system according to claim 5, wherein the control unit executes equalization control in the first mode before or during charging of the power storage module from an external charging device. The power supply system is mounted on the vehicle and
The power storage module supplies electric power to the traveling motor in the vehicle.
The power supply system according to claim 5, wherein the control unit executes equalization control in the second mode before or during traveling by the traveling motor.

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