WO2019003439A1 - Battery system - Google Patents

Abstract

The battery system according to an embodiment provides a battery system that can operate in a situation in which electric power cannot be obtained from the exterior, wherein the battery system is provided with: at least one battery unit U1-Un provided with a plurality of battery modules MDL and a battery-monitoring device 20, the plurality of battery modules MDL including an assembled battery BT, which includes a plurality of secondary cells, and a battery-monitoring circuit 10 for detecting the voltage of the secondary cells and the temperature of the assembled battery BT, the battery-monitoring device 20 controlling the operation of the battery-monitoring circuit 10; a higher-level control device 60 for controlling the operation of the battery unit U1-Un; and a battery device 30 provided with a backup power supply BBT connected to the higher-level control device 60 so as to be capable of supplying power, and a charger CH for charging the backup power supply BBT with energy stored in the battery unit U1-Un.

Description

Battery system

Embodiments of the present invention relate to a battery system.

For example, a battery system using a lead storage battery can be built relatively inexpensively, and is used in various applications such as backup power supply at the time of disaster. On the other hand, in recent years, realization of a battery system using a lithium ion battery with high energy density has been desired in preparation for the demand for power energy in various situations.

A battery unit including a battery assembly composed of a plurality of lithium ion battery cells generally has a configuration for monitoring the voltage of the battery cell and the temperature of the battery assembly. Further, in order to configure a large capacity battery system, it is assumed that a plurality of battery units are used in combination, and a configuration for performing communication between a plurality of battery units is required. In addition, when a plurality of battery units are combined, power for operating the circuit breaker which electrically disconnects the battery unit and the main circuit also increases.
As described above, large-scale battery systems equipped with lithium ion batteries require sufficient power to operate the various configurations to be mounted.

JP, 2014-143795, A

For example, when the battery system is operated by the power supplied from the outside such as a commercial power supply, there is a possibility that the power supply from the outside is stopped at the time of the power failure, and the battery system is stopped. Moreover, the battery system could not be started in an environment where power supply from the outside can not be performed.

An embodiment of the present invention has been made in view of the above circumstances, and an object thereof is to provide a battery system operable in a situation where an external power supply can not be obtained.

A battery system according to an embodiment includes a battery assembly including a plurality of secondary battery cells, and a battery monitoring circuit detecting a voltage of the secondary battery cell and a temperature of the battery assembly. At least one battery unit comprising a plurality of battery modules and a battery management device for controlling the operation of the battery monitoring circuit, a host control device for controlling the operation of the battery unit, and power to the host control device And a battery device including a backup power supply which is connected to be able to be supplied and which has a voltage lower than that of the plurality of battery modules, and a charger which charges the backup power supply with energy stored in the battery unit.

FIG. 1 is a block diagram schematically showing a configuration example of a battery system according to an embodiment. FIG. 2 is a diagram for describing an example of the operation of the battery system according to the embodiment. FIG. 3 is a diagram for explaining an example of the operation of the battery system according to the embodiment.

Embodiment

Hereinafter, a battery system according to an embodiment will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing a configuration example of a battery system according to an embodiment.

The battery system of the present embodiment includes at least one battery unit U1 to Un, a communication circuit 50, an upper control device 60, and a battery device 30.
The plurality of battery units U1 to Un are connected in parallel to one another. Each of the battery units U1 to Un includes a plurality of battery modules MDL, a battery management unit (BMU) 20, a current sensor CS, a service disconnector SDC, and circuit breakers MCM and MCP. There is.

Each of the plurality of battery modules MDL includes a battery pack BT, a battery monitoring circuit (CMU: Cell Monitoring Unit) 10, and a self-diagnosis circuit 11. The assembled batteries BT of the plurality of battery modules MDL are connected in series via the service disconnector SDC.

The plurality of battery modules MDL are main batteries that supply power to the load as a main power source. The plurality of battery modules MDL can also be used as a power source of the battery management device 20 or the host control device 60. The main battery can be increased in voltage according to the number of battery modules MDL connected in series.

The assembled battery BT includes a plurality of secondary battery cells (not shown) of lithium ion batteries. In the present embodiment, the assembled battery BT has, for example, a configuration in which twelve secondary battery cells are connected in parallel, and the two cells connected in parallel are in twelve series, and includes twenty-four secondary battery cells. . As a secondary battery cell of the assembled battery BT, a secondary battery such as a lithium ion battery, a nickel hydrogen battery, a nickel cadmium battery, or a lead storage battery can be used. Because the frequency of use is high, it is desirable to use a lithium ion battery excellent in cycle characteristics. Among lithium ion batteries, a lithium ion battery using lithium titanate for the negative electrode is particularly excellent in cycle characteristics, and it is desirable to adopt it for the assembled battery BT.

Battery monitoring circuit 10 detects the voltage between the positive electrode terminal and the negative electrode terminal of each of the plurality of secondary battery cells of assembled battery BT. Also, the battery monitoring circuit 10 detects the temperature in the vicinity of the battery pack BT at at least one place. The battery monitoring circuit 10 is configured to be able to communicate with a battery management device 20 described later based on, for example, a CAN (Control Area Network) protocol. The battery monitoring circuit 10 periodically transmits information on the detected voltage and temperature to the battery management device 20.

The battery monitoring circuit 10 includes, for example, at least one processor and a memory, and may be configured to realize the above operation by software, and is configured to realize the above operation by a circuit configured by hardware. It may be configured to realize the above operation by a combination of software and hardware.
The self-diagnosis circuit 11 determines the soundness level (SOH) and the life of the battery pack BT based on, for example, information of voltage and temperature detected by the battery monitoring circuit 10 and outputs the result to the battery management device 20. The self-diagnosis circuit 11 can be activated by power supply from the battery management device 20. The self-diagnosis circuit 11 may be incorporated in the battery monitoring circuit 10 or may be incorporated in the battery management apparatus 20.

The service disconnect SDC is a maintenance circuit breaker. The service disconnect SDC is disposed, for example, at a substantially central position of the plurality of battery modules MDL connected in series, and is provided to be able to cut off the electrical connection between the battery modules MDL. By opening the service disconnect SDC at the time of maintenance of the battery units U1 to Un, the safety of the maintenance operation can be secured. The service disconnect SDC is, for example, an electromagnetic contactor, and its operation can be controlled by a control signal from the battery management device 20.

The circuit breakers MCM and MCP are provided to be able to connect or disconnect the plurality of battery modules MDL of the battery units U1 to Un and the main circuit. The circuit breaker MCP switches the electrical connection between the positive terminal of the battery module MDL on the highest potential side and the main circuit on the positive side. The circuit breaker MCM switches the state of electrical connection between the negative terminal of the battery module MDL on the lowest potential side and the main circuit on the negative side. The circuit breakers MCM and MCP are, for example, magnetic contactors, whose operation can be controlled by control signals from the battery management device 20.

The current sensor CS is disposed between the negative electrode terminal of the battery module MDL on the lowest potential side and the circuit breaker MCM. The current sensor CS operates with the power supplied from the battery management device 20. Further, the current sensor CS is configured to be able to communicate with the battery management device 20 based on, for example, the CAN protocol. The current sensor CS periodically detects the current flowing through the plurality of battery packs BT and transmits the current to the battery management device 20.

The battery management device 20 acquires voltage and temperature information from the battery monitoring circuit 10 of the plurality of battery modules MDL. Also, the battery management device 20 acquires, from the current sensor CS, information on the current flowing to the plurality of battery packs BT. The battery management device 20 can calculate SOC (state of charge) of the plurality of battery packs BT (or secondary battery cells) using, for example, information of voltage, temperature, and current.

Furthermore, the battery management device 20 acquires, from the plurality of self-diagnosis circuits 11, values corresponding to the soundness level and the lifetime of the battery pack BT. The battery management device 20 can change the magnitude of the charging current (or discharging current) of the assembled battery BT, for example, according to the soundness level and the life of the assembled battery BT. Further, charging (or discharging) of the assembled battery BT can be stopped or an alarm etc. can be output to notify the replacement time of the assembled battery BT according to the soundness or life of the assembled battery BT. Also, for example, when the battery management device 20 starts up the battery system, it checks the soundness level and the life of the battery pack BT, and when it is determined that the battery system can not be safely started, the host control device 60 does not start the battery system. It can be notified that the system can not be started. With this function, even in a battery system whose capacity is reduced due to the life, it is possible to fully use the performance such as charge and discharge of the secondary battery of the battery system.

The battery management device 20 operates with the power supplied from the host control device 60, and supplies power to the plurality of battery monitoring circuits 10, the self-diagnosis circuit 11, and the current sensor CS. Also, the battery management device 20 can control the operations of the service disconnector SDC and the circuit breakers MCM and MCP based on the control signal from the host control device 60.

The battery management device 20 may include, for example, at least one processor and a memory, and may be configured to implement the above operation by software, and is configured to implement the above operation by a circuit configured by hardware. It may be configured to realize the above operation by a combination of software and hardware.

The battery device 30 includes a backup power supply BBT, a charger CH, and a battery management circuit (BMU) 31. The battery device 30 is, for example, an auxiliary battery that can supply power as a power source of the battery management device 20 or the host control device 60. In addition, the battery device 30 can also be used as a main power source of a connected system.

The charger CH charges the backup power supply BBT with power obtained from the main circuit to which the plurality of battery units U1 to Un are connected. The charger CH can control its operation, for example, by the upper controller 60. It is assumed that the backup power supply BBT is not used for a long period of time, so it is desirable that the backup power supply BBT be float-charged or periodically charged by the charger CH. Furthermore, it is more desirable to be float-charged since periodical charging requires system control.

The backup power supply BBT can supply DC power to the battery management device 20 and the host control device 60. The backup power supply BBT is desirably provided with a battery cell of a lithium ion battery having high safety and excellent cycle characteristics and life characteristics in float charge, and further, among lithium ion batteries, it is preferable to use cycle characteristics and float charge. It is more desirable to provide a battery cell of a lithium ion battery using lithium titanate having excellent life characteristics for the negative electrode.

The backup power supply BBT may have at least a capacity capable of supplying power when the host control device 60 and the plurality of battery units U1 to Un are activated. In the present embodiment, the backup power supply BBT has a lower voltage than the main power supply, and the output voltage of the backup power supply BBT is, for example, 12 V DC or 24 V DC. For example, when the main power supply is a high voltage such as DC 750 V as in a moving container, auxiliary equipment such as a DCDC converter becomes large, which makes it difficult to install main circuit wiring and withstand voltage design. By using the backup power supply BBT, the above problem can be easily solved, and direct current power can be supplied to the battery management device 20 and the host control device 60.

The backup power supply BBT is float-charged by the charger CH. The backup power supply BBT is charged by the charger CH when the capacity decreases. When the plurality of battery units U1 to Un are connected to the main circuit, the backup power supply BBT is always charged, and therefore, it is always in a state of full charge or near full charge. Note that charging of the backup power supply BBT may be performed by DC power such as a solar cell, as well as charging from a commercial power supply.

The battery management circuit 31 includes a self-diagnosis circuit (not shown) that acquires the voltage, temperature, charging (or discharging) current, and the like of the backup power supply BBT and determines the soundness (SOH) and life of the backup power supply BBT. The battery management circuit 31 outputs the soundness level and the lifetime of the backup power supply BBT to the host control device 60. It is assumed that the backup power supply BBT is not used for a long period of time, and it is also required that the backup power supply BBT be reliably available when it should be used. For this reason, it is desirable to periodically determine the soundness level and the lifetime of the backup power supply BBT even during periods when the backup power supply BBT is not used, and to make maintenance possible when the backup power supply BBT deteriorates or breaks down.

The battery management circuit 31 may include, for example, at least one processor and at least one memory, and may be configured to realize the above operation by software, and the above operation is realized by a circuit configured by hardware. It may be configured as described above, or may be configured to realize the above operation by a combination of software and hardware.

The AC / DC converter 40 converts AC power supplied from the commercial power supply 70 into DC power and supplies DC power to the host controller 60. The AC / DC converter 40 may be configured to be switchable between start and stop by, for example, switching a start switch (not shown).
The output line of the backup power supply BBT and the output line of the AC / DC converter 40 are connected to a common power input terminal of the host controller 60 via a backflow prevention element.

The communication circuit 50 is an Ethernet (registered trademark) hub that relays communication between the host control device 60 and at least one battery management device 20. The battery management device 20 transmits information on voltage, temperature, and current to the host control device 60 by, for example, a differential communication method. The host control device 60 transmits a control signal to the battery management device 20 by, for example, a differential communication method.

The host control device 60 is, for example, a battery aggregation unit (BAU), and is configured to be able to control the operation of the plurality of battery units U1 to Un. For example, the host control device 60 performs self-diagnosis whether there is no problem even if voltage is applied to the main circuit of the battery system, and when there is no problem, the circuit breaker to the battery management device 20 of the plurality of battery units U1 to Un Output control signal to close MCM and MCP. The host control device 60 is operated by the power supplied from the AC / DC converter 40 or the battery device 30, and supplies power to the plurality of battery units U1 to Un via the fuses.

Further, the host control device 60 acquires, from the battery management circuit 31, values corresponding to the soundness level and the lifetime of the backup power supply BBT. The host control device 60 can change the magnitude of the charging current (or discharging current) of the backup power supply BBT, for example, according to the soundness level and the life of the backup power supply BBT. In addition, the host control device 60 stops charging (or discharging) of the backup power supply BBT or outputs an alarm or the like notifying the replacement time of the backup power supply BBT according to the soundness or life of the backup power supply BBT. Can. Also, for example, when the battery system is started, the host control device 60 confirms the soundness level and the life of the backup power supply BBT, and when it is determined that the battery system can not be safely started, the battery system can not be started without starting. It is possible to output a warning or the like for informing the user of the state.

In the battery system of the present embodiment, since power is supplied to the host control device 60 from the common power supply line from the commercial power supply 70 and the backup power supply BBT via the diode (backflow prevention element), the backup power supply The host controller 60 can be supplied with power as long as the charging power of the BBT is not exhausted. Therefore, even when the commercial power supply 70 fails, the host control device 60 can continue to operate.

Next, an example of the operation of the battery system will be described.
FIG. 2 and FIG. 3 are diagrams for explaining an example of the operation of the battery system according to the embodiment. In FIG. 2, an example of the operation of the battery system when the battery system is started by the power supplied from the commercial power supply 70 and thereafter the commercial power supply 70 fails is described.

When the battery system is started from the stopped state, for example, when the user operates the start switch, power is supplied from the commercial power source 70 to the host controller 60 via the AC / DC converter 40. At this time, when power is supplied from the AC / DC converter 40, the power supply from the backup power supply BBT is stopped.

The host controller 60 is activated by power supply from the power supply line, and performs self-diagnosis whether there is no problem even if voltage is applied to the main circuit of the battery system, for example. Power is supplied to the device 20.

The battery management device 20 is activated by being supplied with power from the host control device 60, and starts power supply to the battery monitoring circuit 10. For example, the battery management device 20 notifies the host control device 60 that the battery monitoring circuit 10 has started normally after the normal start.

The host control device 60 receives a notification from the battery management device 20 that it has started normally, and sends control signals (Power on) to the battery management devices 20 of the plurality of battery units U1 to Un to close the circuit breaker MCM and MCP. Output The battery management device 20 closes the circuit breakers MCM and MCP in accordance with the control signal from the upper control device 60 to connect the main circuit and the plurality of battery modules MDL.

In an environment where power from the commercial power source 70 can be used, the battery system is activated as described above, power is supplied from the commercial power source 70 to the host controller 60, and the circuit breakers MCM and MCP are in a closed state. Power can be supplied to the load connected to the

When a power failure of the commercial power supply 70 occurs while the battery system is operating by the power from the commercial power supply 70, for example, the voltage applied from the AC / DC converter 40 to the power supply line of the host controller 60 decreases. As a result, the voltage applied from the backup power supply BBT to the power supply line rises and switches to the power supply from the backup power supply BBT.
When power supply from the backup power supply BBT to the host controller 60 starts, charging of the backup power supply BBT is started by the charger CH so that the capacity of the backup power supply BBT is always fully charged.

When the power from the commercial power supply 70 is stopped, power is supplied from the backup power supply BBT to the host controller 60 as described above, and the circuit breakers MCM and MCP are closed, and power to the load connected to the main circuit is supplied. Supply can be continued.

An example of the operation of the battery system when starting the battery system in an environment where power from the commercial power source 70 can not be used will be described with reference to FIG.
When the battery system is started up in an environment where power from the commercial power supply 70 can not be used, for example, power is supplied from the backup power supply BBT to the host control device 60 when the user operates the start switch. At this time, the commercial power source 70 and the AC / DC converter 40 are not electrically connected, and the power supply from the commercial power source 70 is stopped.

The host controller 60 is activated by supplying power from the power supply line, and performs self-diagnosis whether there is no problem even if voltage is applied to the main circuit of the battery system, for example. Power is supplied to the management device 20. Also, for example, when the host control device 60 acquires the soundness level and the lifetime of the backup power supply BBT from the battery management circuit 31 and determines that it can not safely start up, it can not start up without starting up the battery system. It is possible to output a warning or the like for informing the user of the state.

The battery management device 20 is activated by being supplied with power from the host control device 60, and starts power supply to the battery monitoring circuit 10. For example, the battery management device 20 can notify the host control device 60 that the battery monitoring circuit 10 and the self-diagnosis circuit 11 have normally started up after the normal startup. The battery management device 20 receives the soundness level and the lifetime of the battery pack BT from the self-diagnosis circuit 11, and activates the battery monitoring circuit 10 when it is determined that the battery system can not be safely started based on the soundness level and the lifetime. Alternatively, a notification may be sent to the upper control apparatus 60 to the effect that it can not be activated (cannot be activated normally).

Also, for example, when the host control device 60 receives the soundness level and the lifespan of the plurality of battery packs BT from the battery management device 20, and determines that it can not be safely started based on the soundness level and the lifespan, When the device 20 does not start up normally, it is possible to output a warning or the like for notifying the user that the battery system can not be started without starting up the battery system.

The host control device 60 receives a notification from the battery management device 20 that it has started normally, and sends control signals (Power on) to the battery management devices 20 of the plurality of battery units U1 to Un to close the circuit breaker MCM and MCP. Output The battery management device 20 closes the circuit breakers MCM and MCP in accordance with the control signal from the host controller 60 to connect the main circuit and the plurality of battery modules MDL.
When the plurality of battery units U1 to Un are connected to the main circuit, charging of the backup power supply BBT is started by the charger CH.

In an environment where the power from the commercial power source 70 can not be used, the battery system is activated as described above, power is supplied from the backup power source BBT to the host controller 60, and the circuit breakers MCM and MCP are closed. Power can be supplied to the load connected to the

As described above, the battery system of the present embodiment can be started even in an environment where the power from the commercial power source 70 can not be used. In addition, since the battery system can operate while charging the backup power supply BBT by the charger CH, it is possible to continue the operation using the energy stored in the plurality of battery units U1 to Un.

When the power is supplied from the backup power supply BBT to the host control device 60 in an environment where the power from the commercial power supply 70 can not be used, and when the circuit breakers MCM and MCP are open, the plurality of battery units U1 are Since the energy stored in ̃Un can not charge the backup power supply BBT, the host control device 60, the battery management device 20 and the battery monitoring circuit 10 are operated only with the energy stored in the backup power supply BBT. That is, according to the present embodiment, for example, when monitoring the voltage or temperature of the assembled battery BT when the load is not connected to the main circuit, equalizing the SOC of the assembled battery BT, at the time of maintenance, etc. The present invention can provide a battery system that can be started up even when no voltage is applied to the main circuit. In addition, in the mobile unit etc., an external power source is required as a power source when activating the battery system, but the battery system of the present embodiment is provided with the battery device 30 as an auxiliary power source, and can be activated by power supply from the battery device 30. It is.

As described above, according to the battery system of the present embodiment, it is possible to provide a battery system that can operate in a situation where power can not be obtained from the outside. Furthermore, the battery system of the present embodiment can operate while charging the backup power supply BBT with the energy stored in the battery units U1 to Un, and can continue operation for a long time.

While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof. For example, in the above-described embodiment, the battery assembly BT is not limited to a lithium ion battery, and may be, for example, a nickel hydrogen battery or a lead battery.

Claims (3)

A plurality of battery modules including a battery assembly including a plurality of secondary battery cells, a battery monitoring circuit detecting a voltage of the secondary battery cells and a temperature of the battery assembly, and control operations of the battery monitoring circuit At least one battery unit comprising: a battery management device;
A host control unit that controls the operation of the battery unit;
A battery comprising: a backup power supply connected to the host controller so as to be capable of supplying power; and a backup power supply having a voltage lower than that of the plurality of battery modules, and a charger charging the backup power supply with energy stored in the battery unit. Device, and a battery system. It further comprises an AC / DC converter that converts AC power output from a commercial power source into DC power and outputs it.
2. The power supply line according to claim 1, wherein said AC / DC converter and said backup power supply are capable of supplying power to a common power supply line connected to a power supply input terminal of said host controller via a backflow prevention element. Battery system. The battery system according to claim 1, wherein the backup power supply includes a lithium ion battery using lithium titanate as a negative electrode.

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