GB2467231A

GB2467231A - High voltage battery controller with isolation

Info

Publication number: GB2467231A
Application number: GB1001067A
Authority: GB
Inventors: Hiroshi Arita; Seiji Ishida; Takayoshi Nishino; Eiichi Toyota; Yutaka Sato
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2009-01-27
Filing date: 2010-01-22
Publication date: 2010-07-28
Anticipated expiration: 2030-01-22
Also published as: GB2467231B; JP2010178400A; GB201001067D0; CN101789530A; JP5028436B2; CN101789530B

Abstract

A technique for monitoring a status of a battery cell (21) is provided and exposure to high voltage during maintenance works is eliminated. A plurality of the battery cells (21) are connected in series to form an assembled battery (2), and a plurality of the assembled batteries (2) are connected in series to form a serial block, thereby forming a battery. A battery controller (1) is provided for each assembled battery (2), and the battery controllers (1) and a main controller (4) are communicably connected together. The battery controller (1) insulates two communication parts (32,31b) from a processing part (20). Both of the communication parts communicably connected together (32, 31b) have the same voltage, and the voltage is set to that of a negative electrode side of the assembled battery (2).

Description

The present invention relates to a battery system for realizing a compact size of a control system that performs monitoring and control of a status of a battery cell, corresponding to a high voltage of a battery having a structure in which battery cells are connected in series to form an assembled battery and the assembled batteries are connected in series.

In relation to a secondary battery such as a Lead-acid battery, a Nickel-metal hydride battery, and a Lithium-ion battery mounted on power machines such as vehicles and railroad vehicles or UPS (Uninterruptible Power Supply) for backup, a structure in which battery cells are connected in series and in parallel is known to obtain a reqii.ired voltage and current.

Both of JP-A-09-139237 and JP-A-2003-70179 disclose a battery system for a hybrid vehicle.

In JP-A-09-139237, combinations of a battery cell and a voltage monitoring unit for monitoring a voltage of the battery cell are connected in series in a structure in which a Nickel-metal hydride battery cells are connected in series. Each voltage monitoring unit receives a power supply from a battery cell to be monitored.

The voltage monitoring units are linked together via a communication line, and a photocoupler insulates the inside of the voltage monitoring unit to secure an isolation voltage. By doing so, since a voltage of the Nickel-metal hydride battery to be monitored is about 12 volts, the electrical insulation can be made only by applying the insulation, on the communication line side of the voltage monitoring unit.

The entire voltage of all series connections is prevented from being applied to the voltage monitoring unit, and safety is enhanced.

JP-A-2003-70179 discloses a method of monitoring a voltage of a battery cell and estimating the charging amount of all the battery cells connected in series to prevent a battery from being overcharged or overdischarged in a battery device in which Lithium-ion battery cells are connected in series. A photocoupler is used for insulation between a voltage monitoring circuit and state-of-charge estimating device for the battery cell. The state-of-charge estimating device receives a power supply from the outside, whereby the entire voltage of series connections is prevented from being applied to the state-of-charge estimating device itself to enhance the safety.

However, a voltage of 1500 to 2000 volts is required of a battery mounted on a railroad vehicle, as compared with the fact that a voltage of a battery mounted on a hybrid vehicle is about 500 volts or less.

Therefore, when the battery for a hybrid vehicle is applied to a railroad vehicle as it is, an insulator of a battery monitoring unit must withstand a voltage of 1500 to 2000 volts. As a result, an insulation isolation voltage between the voltage monitoring circuit and state-of-charge estimating device for the battery cell becomes large, and therefore, a cost and size of the insulator on the state-of-charge estimating device side increase.

Since increasing of voltage and capacity of a battery accompanies a high voltage part in the battery system, the battery is fraught with a danger such as electric shock during the maintenance works.

In view of the foregoing, it is a preferred aim of the present invention to provide a battery control system and battery system in which a compact size and low cost of an apparatus are attained, corresponding to high voltage and high capacity of a battery having a structure in which battery cells are connected in series to form an assembled battery and the assembled batteries are connected in series and in parallel.

To accomplish the above-described objects, according to one aspect of the present invention, there may be provided a plurality of battery controllers. Each battery controller includes: a controller; a first communication circuit that communicates with another battery controller connected adjacent to the battery controller; a second communication circuit that communicates with yet another battery controller connected adjacent to the battery controller; a power circuit that receives a power supply from the assembled battery and generates a power for the controller and for the second communication circuit of the battery controller; a first insulating unit that insulates the controller and the first communication circuit; and a second insulating unit that insulates the controller and the second communication circuit, wherein: the first communication circuit of the battery controller and the second communication circuit of the another battery controller are connected to each other.

According to the present invention, there is provided a battery control system and battery control method in which a compact size and low cost of an apparatus are attained, corresponding to a high voltage of a battery having a structure in which battery cells are connected in series to form an assembled battery and the assembled batteries are connected in series and in parallel.

IN THE DRAWINGS

FIG. 1 illustrates a structure according to one embodiment of a battery control system of the invention; FIG. 2 illustrates a circuit diagram for explaining voltages and insulation of a battery controller of FIG. 1; FIG. 3 illustrates each voltage within the battery controller of FIG. 2; FIG. 4 illustrates a structure according to another embodiment of the battery control system of the invention; FIG. 5 illustrates each voltage within the battery controller of FIG. 4; FIG. 6 illustrates a structure according to yet another embodiment of the battery control system of the invention; FIG. 7 illustrates each voltage within the battery controller of FIG. 6; FIG. 8 illustrates a structure according to yet another embodiment of the battery control system of the invention; FIG. 9 illustrates each voltage within the battery controller of FIG. 8; FIG. 10 is a structure diagram of a battery system in which the battery control systems of FIG. 1 are connected in a two-parallel manner; FIG. 11 is a structure diagram of the battery system in which the battery control systems of FIG. 10 are connected in a two-parallel manner using another method; and FIG. 12 is a structure diagram in which both of the battery controllers in the battery control system of FIG. 10 are connected by yet another method.

Embodiments according to the present invention will be described with reference to the accompanying drawings.

Embodiments will be described on a battery control system according to the present invention with reference to FIGS. 1 to 12.

FIG. 1 illustrates a structure according to one embodiment of the battery control system of the invention.

A battery control system 1000 has a structure in which a plurality of combinations of a battery controller 1 and an assembled battery 2 are connected in series. The assembled battery 2 has a structure in which a plurality of battery cells 21 are connected in series, and an output voltage of the assembled battery 2 is on the order of several hundred volts. Further, the assembled battery 2 has a positive terminal 23 and a negative terminal 24, a power stored in each batter cell is charged and discharged via the terminals 23 and 24. The present embodiment depicted in FIG. 1 has a structure in which three battery controllers 1-b, 1, and 1-a are cascade-connected. Each battery controller 1-b, 1, and 1-a has the same inside circuit structure as a whole. Note, however, that in the inside of the battery controller 1-b of FIG. 1, a part of a circuit is not shown. The battery controller 1-b is potentially higher than the battery controller 1. The battery controller 1. is potentially higher than the battery controller 1-a. That is, it can be said that the battery controller 1-b has the highest electric potential among three battery controllers. The battery control system 1000 according to the present invention may have a structure in which more than three battery controllers are cascade-connected.

The battery controller 1 performs processing to monitor the battery cells 21, and both of the battery controllers 1 and 1-a adjacent to each other are coupled together via a communication line 50. The battery controller 1-a reports monitoring processing results to a main controller 4.

The battery controller 1 is connected to the assembled battery 2 via a power line 3, and a power necessary for the processing of the battery controller 1 is supplied by the assembled battery 2.

Two battery controllers 1 and 1-a connected to two assembled batteries 2 and 2-a that are potentially close to each other are coupled together via the communication line 50 and insulated, whereby a voltage between the two battery controllers 1 and 1-a can be suppressed to a voltage of the assembled battery 2 irrespective of the number of series. In other words, the battery controller 1 is burdened with an isolation voltage as much as a voltage of the assembled battery 2, thereby constituting the battery control system irrespective of the number of series of the assembled battery 2. In FIG. 1, the battery controller 1 is connected to the one assembled battery 2. The battery controller 1 may be connected to serially-connected plural assembled batteries 2 via the power line 3.

A structure of the battery controller 1 will be described below.

The battery controller 1 is constituted by a power circuit 10, an MPU (Micro Processor Unit) 20, communication circuits 31 and 32, photocouplers 41 and 42 as an insulating element, a relay 100, and an intermediate voltage generating circuit 110 as series resistors for voltage dividing. In addition, a battery controller connected to the battery controller 1 via the communication circuit 31 and the communication line is defined as a (potentially) lower battery controller 1-a, and a battery controller connected to the battery controller 1 via the communication circuit 32 and a communication line 50-b is defined as a (potentially) higher battery controller 1-b.

The power circuit 10 receives a power supply from the assembled battery 2, generates driving power of several volts for the MPU 20 and that for the communication circuit 32 and for the communication circuit 31-b of the higher battery controller 1-b, respectively, and supplies the driving power to the MPU via a power line 131 and to the communication circuit 32 and the communication circuit 31-b of the higher battery controller 1-b via a power line 132, respectively. In other words, a power supply of the communication circuit 31 is supplied by the power circuit 10-a of the lower battery controller 1-a. On this occasion, the power circuit isolates the generated driving power for the MPU 20 from the generated driving power for the communication circuit 32 and for the communication circuit 31-b of the higher battery controller 1-b.

On the other hand, the MPU 20 and the communication circuit 31 are coupled together via the photocoupler 41 for insulation, and the MPU 20 and the communication circuit 32 are coupled together via the photocoupler 42 for insulation, respectively.

The power lines 3 connect the positive and negative terminals 23, 24 of the assembled battery 2 via the relay 100 to the intermediate voltage generating circuit 110 and the power circuit 10. The relay 100 is ON-OFF controlled by a signal line 135-a from the lower battery controller 1-a, and is turned on when a predetermined current flows through the signal line 135-a, or turned off when a less current than the predetermined current flows through the signal line 135-a. There are provided with a wiring line 133 for determining a voltage for supplying a power to the MPU and a wiring line 134 for determining a voltage of -10 -the communication circuit 31 connected to the lower battery controller 1-a via the communication line 50.

By this wiring line 134, an electric potential of devices such as the communication circuit 31 becomes the same as that of the negative terminal 24 of the assembled battery 2.

As to a power ON sequence in the battery control system 1000, when a relay 100-a is turned on by the main controller 4, a power circuit 10-a is started up and a power is supplied to an MPU 20-a, a communication circuit 32-a, and a communication circuit 31. When the started MPU 20-a issues a power ON command of the higher battery controller 1 to the communication circuit 32-a via a photocoupler 42-a, the communication circuit 32-a turns on the relay 100, by causing a predetermined current to flow through the signal line 135-a, and starts up the power circuit 10 of the battery controller 1. As described above, the power supplies are turned on in sequence from the lower battery controller to the higher battery controller.

Meanwhile, as to a power OFF sequence, when the main controller 4 issues a power OFF command, the command is transferred to all the battery controllers 1, 1-a, and 1-b via the communication line 50, and all the MPUs 20, 20-a, and 20-b of the battery controllers 1, 1-a, and 1-b execute an end processing. When the end processing is completed, the highest battery controller 1-b informs via the communication line 50-b -11 -the lower battery controller 1 that the end processing is completed. When receiving this information, the lower battery controller 1 switches OFF the relay 100-b within the highest battery controller 1-b via the signal line 135. Thereafter, when receiving that the MPU 20 completes the end processing, the battery controller 1 informs the lower battery controller 1-a that the end processing is completed.

As described above, the power supplies are turned off in sequence from the highest battery controller to the lowest battery controller. When finally receiving the end processing completion signal from the lowest battery controller 1-a, the main controller 4 turns off the relay 100-a via the signal line 135-b, and as a result, turns off all the battery controllers 1, 1-a, and 1-b.

When all the battery controllers 1, 1-b, and 1-a should be urgently turned off 4 cuts off a current flowing through the signal line 135-b for controlling ON/OFF of the relay 100-a within the lowest battery controller 1-a to turn off the relay 100-a. As a result, since the power circuit 10 of the battery controller 1 is stopped, the communication circuit 32 is also stopped to cut off a current flowing through the signal line 135 to the relay 100-b within the highest battery controller 1-b. Therefore, the relay 100-b is switched OFF and the power circuit 10-b within the battery controller 1-b is stopped. As described -12 -above, when cutting of f a current flowing through the signal line 135-b for controlling the relay 100-a, all the higher battery controllers 1 and 1-b can be turned off.

Four different electric potentials and isolation held by the battery controller 1 will be described in detail with reference to FIG. 2. The battery controller 1 has a power supply potential 150 of the power circuit 10, a microcomputer potential 151 of the MPU 20, a communication L (Low) potential 152 of the communication circuit 31, and a communication H (High) potential 153 of the communication circuit 32.

The power supply potential 150 is a potential of the negative terminal 24 of the assembled battery 2, and the microcomputer potential 151 is determined by the wiring lines 134 and 133 from the intermediate voltage generating circuit 110 and is an intermediate potential of an output voltage from the assembled battery 2.

Meanwhile, the communication L voltage 152 is determined by the wiring line 134 from the negative terminal 24 of the assembled battery 2, and becomes the same as that of the negative terminal 24 of the assembled battery 2. The communication H potential 153 becomes the same as the communication L potential 152-b of the highest battery controller 1-b (i.e., a voltage of the negative terminal 24-b of the assembled battery 2-b) . That is, the communication L potential 152 and the communication H potential 153-a of the lowest -13 -battery controller 1-a are the same as each other, and the communication H potential 153 and the communication L potential 152-b of the highest battery controller 1-b are the same as each other.

As previously described, the power supply voltage 150, the microcomputer voltage 151 and the communication H potential 153 are insulated from each other by the power circuit 10. The MFU 20 with the microcomputer voltage 151 and the communication circuit 31 with the communication L potential 152 are insulated from each other by the photocoupler 41. The MPU 20 with the microcomputer voltage 151 and the communication circuit 32 with the communication H potential 153 are insulated from each other by the photocoupler 42. Further, the power supply voltage 150 and the communication L potential 152 are insulated from each other by the relay 100, and the power circuit can be turned on/off by the relay 100.

By a two-stage insulation including the insulation between the communication L potential 152 and the microcomputer voltage 151 and further insulation between the microcomputer voltage 151 and the communication H potential 153, a photocoupler with lower isolation voltage can be used, and therefore, the size and cost can be reduced as compared with one-stage insulation between the microcomputer and the communication circuit.

FIG. 3 is a table obtained by collecting each -14 -voltage of 150 to 153 in the structure illustrated in FIG. 2 during ON/OFF of the relay 100. In addition, a potential at the positive terminal 23 of the assembled battery 2 is denoted by VH, and another potential at the negative terminal 24 of the assembled battery 2 is denoted by VL. When the relay 100 is turned off, the power circuit 10 is not connected to the negative terminal 24 of the assembled battery 2, and therefore, the power supply voltage 150 is V of the positive terminal 23. Meanwhile, when the relay 100 is turned on, the power circuit 10 is connected to the negative terminal 24 of the assembled battery 2, and therefore, the power supply voltage 150 is VL of the negative terminal 24. That is, when the relay 100 is turned off, a voltage applied between both ends of the relay is VH-VL. When the relay 100 is turned on, two potentials of both ends of the relay 100 are VL, and therefore, a voltage applied between both ends of the relay 100 is equal to zero volt (the same potential) Further, since an ON/OFF control signal 135-a of the relay 100 is always VL by the wiring line 134, the entire voltage across the relay 100 is VL when the relay is turned on. That is, during the switching ON of the relay 100, i.e., when a current flows through the relay 100, the proposed technique prevents an unnecessary load from being applied to the relay 100 and can contribute to a long service life of the relay 100.

-15 -when the relay 100 is turned off, a voltage applied between both ends of the photocoupler 42 is zero volt (the same potential) and another voltage applied between both ends of the photocoupler 41 is V1-VL. Meanwhile, when the relay 100 is turned on, both of the voltage applied between both ends of the photocoupler 42 and another voltage applied between both ends of the photocoupler 41 are (VH-VL)/2. In short, when a current flows through the relay, both of the one voltage applied between both ends of the photocoupler 42 and the another voltage applied between both ends of the photocoupler 41 are dropped.

As described above, the two-stage insulation is provided between the voltages 153 and 152 using the photocouplers 41 and 42 having isolation voltage VH-VL as a potential between both ends of the assembled battery 2. This two-stage insulation makes it possible to structure the battery control system in which the plurality of assembled batteries 2 are connected in series using a photocoupler with low isolation voltage and to attain the compact and inexpensive battery control system.

As illustrated in FIG. 2, when a structure of the communication L potential 152 is further determined by the wiring line 134 from the negative terminal 24 of the assembled battery 2, the communication L potential 152 becomes the same as that of the negative terminal 24 of the assembled battery 2. When the connection of -16 -each assembled battery 2 is cut off to perform maintenance works, the negative terminal 24 of each assembled battery 2 is connected to the ground level, and as a result, a communication line voltage of each battery controller is always equal to the ground voltage. During the maintenance tasks, this function enables a high voltage unit of the battery control system to be eliminated and an accident such as electric shock to be prevented from occurring.

Subsequently, a structure in which the assembled batteries 2 and 2-a are connected in parallel will be described with reference to FIGS. 4 and 5.

When the assembled batteries 2 and 2-a are connected in parallel, the negative terminals 24 and 24-a of the assembled batteries 2 and 2-a have the same potential as each other. Accordingly, both of the communication L potential 152 of the battery controller 1 and communication H potential 153-a of the battery controller 1-a are VL (hereinafter, denoted by the communication H potential 153-a) FIG. 5 illustrates each potential of the battery controller 1-a in the case of ON/OFF of the relay 100. A potential of the communication H potential 153-a is VL irrespective of ON/OFF of the relay 100. Also, in this case, when the relay 100 is turned on, the all of the potentials around the relay are the same as VL. When the relay 100 is turned off, one voltage applied between both ends of the -17 -photocoupler 42 is VH-VL and another voltage applied between both ends of the photocoupler 41 is VH-VL. When the relay 100 is turned on, both of one voltage applied between both ends of the photocoupler 42 and another voltage applied between both ends of the photocoupler 41 are VH-VL/2.

Accordingly, whether the assembled batteries 2 are connected in series or in parallel, potential difference between the potentials 150 to 153 is the same as each other. It can be seen that the battery controller 1 having the structure according to the present embodiment can be used whether the assembled batteries 2 are connected in series or in parallel.

From the above description, also when the

plurality of assembled batteries 2 are connected in parallel, the battery control system can be realized by using the battery controller 1, and further, the battery control system with high voltage and high capacity can be inexpensively realized.

Further, a voltage of the communication line that connects the battery controllers 1 and 1-a is the same as those of the negative terminals 24 and 24-a of the assembled batteries 2 and 2-a, and therefore, the voltage of the communication line 50 can be reduced.

Subsequently, a structure of a battery controller 1' that determines each voltage of 150 to 153 using a method different from that according to the -18 -present embodiment will be described as another embodiment of the invention with reference to FIGS. 6 to 9. A difference from the above-described embodiment is how to determine the communication H potential 153 and the communication L potential 152.

FIG. 6 illustrates a structure in which combinations of the assembled battery 2 and the battery controller 1' are connected in series.

In FIG. 6, the communication H potential 153 is determined by the wiring line 136 from the positive terminal 23 of the assembled battery 2, and is a potential level of the positive terminal 23 of the assembled battery 2. Meanwhile, the communication L potential 152 is the same as the communication H potential 153-a of the lower battery controller 1-a (i.e., a potential level of the positive terminal 23-a of the assembled battery 2-a) . In addition, the communication L potential 152 and the communication H potential 153-a of the lower battery controller 1-a are the same as each other. The communication H potential 153 and the communication L potential 152-a of the higher battery controller 1-a are the same as each other.

In the same manner as in FIG. 1, the power supply voltage 150, the microcomputer voltage 151 and the communication H potential 153 are insulated from each other by the power circuit 10. the MP(J 20 with the microcomputer voltage 151 and the communication -19 -circuit 31 with the communication L potential 152 are insulated from each other by the photocoupler 41, and the MPU 20 with the microcomputer voltage 151 and the communication circuit 32 with the communication H potential lS3are insulated from each other by the photocoupler 42. Further, the power supply voltage 150 and the communication L potential 152 are insulated from each other by the relay 100, and the power circuit can be turned on/off by the relay 100.

As illustrated in FIG. 6, when determined by the wiring line 136 from the positive terminal 23 of the assembled battery 2, the communication H potential 153 is the same as that of the positive terminal 23 of the assembled battery 2. That is, when performing the maintenance works, a potential of the communication line of each battery controller in which the connection of each assembled battery is cut off is always one raised by a potential of one assembled battery from the ground potential.

FIG. 7 is a table obtained by collecting each potential of 150 to 153 in the structure illustrated in FIG. 6 at ON/OFF of the relay 100. In addition, a potential at the positive terminal 23 of the assembled battery 2 is denoted by V1., and another potential at the negative terminal 24 of the assembled battery 2 is denoted by VL. When the relay 100 is turned off, the power circuit 10 is not connected to the negative terminal 24 of the assembled battery 2, and therefore, -20 -the power supply potential 150 is yR of the positive terminal 23. Meanwhile, when the relay 100 is turned on, the power circuit 10 is connected to the negative terminal 24 of the assembled battery 2, and therefore, the power supply potential 150 is VL of the negative terminal 24. That is, when the relay 100 is turned off, a voltage applied between both ends of the relay is VH-VL. When the relay 100 is turned on, two potentials of both ends of the relay 100 are VL, and therefore, a voltage applied between both ends of the relay 100 is equal to zero volt (the same potential) Further, since an ON/OFF control signal 135-a of the relay 100 is always VL by the wiring line 134, the all potentials around the relay 100 are VL when the relay 100 is turned on. That is, during the switching ON of the relay 100, i.e. when a current flows through the relay 100, the proposed technique prevents an unnecessary load from being applied to the relay 100 and can contribute to a long service life of the relay 100.

Next, FIG. 8 illustrates yet another embodiment in which the assembled batteries 2 and 2-a are connected in parallel using the battery controller 1'.

FIG. 9 is a table showing each potential of to 153 in the structure illustrated in FIG. 8 at ON/OFF of the relay 100. The communication L potential 152 is VH irrespective of ON/OFF of the relay 100. The -21 -reason is that the potential 153-a of the battery controller l'-a, which is the same as the communication L potential 152, is a potential of the positive terminal 23-a of the assembled battery 2-a by the wiring line 136-a. In this case, when the relay 100 is turned on, two potentials of both ends of the relay 100 are VL, and a potential of the ON/OFF control signal 135-a of the relay 100 is VH. Accordingly, when the relay 100 is turned on, a voltage of VH-VL is applied to the relay 100. Further, when the relay 100 is turned off, a potential applied between both ends of the photocoupler 42 is 0 volt and another voltage applied between both ends of the photocoupler 41 is VR-VL. When the relay 100 is turned on, a voltage applied between both ends of each of the photocouplers 41 and 42 is (VH-VL)/2. Accordingly, in the case of FIG. 6, the isolation voltage between the input and output of the photocoupler 42 can be reduced up to (VH-VL)/2.

From the above description, also when the

plurality of assembled batteries 2 are connected in series and in parallel, the battery control system can be realized by using the battery controller 1' illustrated in FIGS. 6 and 8, and further, the battery control system with high voltage and high capacity can be inexpensively realized.

On the other hand, a potential of the communication line 50 that connects the battery controllers 1' and 1'-a is the same as those of the -22 -positive terminals 23 and 23-a of the assembled batteries 2 and 2-a, and therefore, the potential of the communication line 50 becomes high as compared with the battery controller 1 according to the present embodiment illustrated in FIGS. 1 and 4.

Subsequently, FIG. 10 illustrates a structure of the battery control system with larger capacity at the time when a plurality of the battery control systems are connected in parallel.

FIG. 10 illustrates an example of a battery system 2000 in which a battery control system 1001 is constituted by using the battery controllers 1-a, 1-b, 1-c. The battery system 2000 has a structure in which the battery control systems 1001 and 1001-a are connected by a host controller 5. In the example, the battery system 2000 is constituted by the two battery control systems 1001 and 1001-1, and each of the plurality of battery control systems has the same structure as each other.

In each battery control system 1001, the plurality of assembled batteries 2 are connected in series via switches 62, and each assembled battery 2 is connected to the battery controller 1 via the power line 3, respectively.

A positive terminal of the highest assembled battery 2-a connected in series is connected to a terminal 81, and a negative terminal 24 of the lowest assembled battery 2-c is connected to a terminal 82.

-23 -Via the terminals 81 and 82, a power held by each assembled battery 2 is charged and discharged.

Further, the assembled batteries 2-a and 2-b are connected via a switch 62-a. The switch 62-a switches whether to connect the assembled batteries 2-a and 2-b, or to connect the negative electrode side of the assembled battery 2-a to the ground 83 via a resistor 63-a. Meanwhile, a switch 61 connects or separates the positive terminal of the assembled battery 2-a and the terminal 81. In addition, the switches 61, 62-a, 62-b, and 62-c operate in conjunction with each other.

On the other hand, the battery controllers 1-a, 1-b, ..., 1-c are connected together via the communication lines 50, and the lowest battery controller 1-c is connected via a communication line 50-d to the main controller 4 that controls the entire battery system 2000. An apparatus 6 that is installed within the battery control system 1001 and that includes a fan for cooling the assembled battery 2 and a voltage sensor and current sensor for measuring voltages and currents between the terminals 82 and 83 is connected to the main controller 4. The main controller 4 controls the apparatus 6 by data input from various sensors or information from the battery controller 1.

The main controller 4 receives information transmitted from the battery controller 1 acquires a value of current flowing through the assembled battery -24 2 from a current sensor (not shown) and also acquires a value of voltage of the assembled battery 2 from a voltage sensor (not shown) to monitor the condition of the assembled battery 2. The condition of the assembled battery 2 includes SOC (State Of Charge), allowable charging/discharging current and temperature.

The current sensor and the voltage sensor may detect the current and voltage of only the assembled battery 2. The main controller 4 transmits information about the condition of the assembled battery 2 to the host controller 5.

Both of the main controllers 4 and 4-1 are connected via a communication line 51. In FIG. 10, both of the main controllers 4 and 4-1 are connected in a multi-drop connection, or may be connected by an individual connection.

In the battery control system 2000, the battery controller 1 obtains status information data of each assembled battery 2 and communicates the data to the main controller 4 via the communication line 50.

For example, the battery controller 1-a communicates with the main controller 4 via a communication line 50-a, the battery controller 1-b, the communication lines 50-b and 50-c, the battery controller 1-c, and the communication line 50-d.

That is, the battery controller 1-b transmits status information data from the battery controller 1-a via the communication line 50-b in addition to status -25 -information data of the assembled battery 2-b. As described above, each battery controller adds the status information data of the connected assembled battery 2 to the received status information data to transmit the added data.

When the switch 61 is separated and the switches 62-a, 62-b, and 62-c are connected to the resistor 63 side, all the negative terminals of the assembled batteries 2 are connected to the ground 83.

By doing so, both of the communication L potential 152 and voltages of the communication lines 50 of the battery controller 1 are the same as that of the ground 83. At the same time, since the terminal 81 is separated from the positive electrode side of the assembled battery 2-a, danger such as electric shock is eliminated and an operation can be safely performed during the removal and exchange of the assembled battery 2 and the communication line 50.

At the moment when each switch 62-a, 62-b, and 62-c is connected to the resistor 63 side, since a voltage of each assembled battery connected in series remains in the circuit, a large current flows to the ground, and as a result, danger such as electric shock is left. Therefore, the resistors 63 are provided between the switches 62-a, 62-b, and 62-c and the ground 83 to prevent a large current from flowing, and danger such as electric shock can be eliminated.

Subsequently, FIGS. 11 and 12 illustrate -26 -another connection method of the battery control system 1001. FIG. 11 illustrates a structure in which the battery controllers and so on are connected in a two-parallel manner within one battery control system 1001.

A first line subsystem is constituted by the assembled batteries 2-a to 2-c and the battery controllers 1-a to i-c connected to the assembled batteries 2-a to 2-c, and a second line subsystem is constituted by the assembled batteries 2-a-i to 2-c-i and the battery controllers 1-a-i to i-c-i connected to the assembled batteries 2-a-i to 2-c-i. The main controller 4 is connected to the battery controllers 1-c and 1-c-i via the communication lines 50-d and 50-d--1, respectively.

In addition, the apparatus 6 included in the battery control system 1001 is connected to the main controller 4.

The main controller 4 receives information transmitted from the battery controller 1 acquires a value of current flowing through the first line of assembled batteries 2-a to 2-c and the assembled batteries 2-a-i to 2-c-i from a current sensor (not shown) and also acquires a value of voltage of the first line of assembled batteries 2-a to 2-c and the assembled batteries 2-a-i to 2-c-i from a voltage sensor (not shown) to monitor the condition of the first line of assembled batteries 2-a to 2-c and the assembled batteries 2-a-i to 2-c-i. The condition of the first line of assembled batteries 2-a to 2-c and -27 -the assembled batteries 2-a-i to 2-c-i includes SOC, allowable charging/discharging current and temperature.

The main controller 4 transmits information about the condition of the assembled battery 2 to the host controller 5.

FIG. 11 illustrates an example of two-parallel structure, and the proposed battery control system 1001 can be constituted in a three or more-parallel manner using the same connection method.

Further, FIG. 11 illustrates as an example a structure in which both the battery controllers 1 are connected via each communication line 50 in each parallel subsystem, and FIG. 12 illustrates a system in which the battery controllers 1 with the same voltage are connected and then connected to the battery controller 1 of higher voltage group. FIG. 12 illustrates an example of two-parallel structure, and the proposed battery control system 1001 can be constituted in a three or more-parallel manner using the same connection method.

Also in FIGS. ii and 12, in the same manner as in FIG. 10, when the switches 62 are connected to the ground 83 side, all the negative terminals of the assembled batteries 2 are connected to the ground 83.

Therefore, all voltages of the communication lines 50 are the same as that of the ground 83, and safety of maintenance works such as exchange of the assembled battery 2 can be secured.

-28 -The above-described embodiment is applicable to a field in which a power storage device with high capacity is used. It is considered that when the proposed battery system is particularly applied to a railroad field in which a high capacity and compact size are required and maintenance works are necessary, a large effect is exerted.

Claims

-29 -CLAIMS: 1. A battery control system that controls a battery having a plurality of connected assembled batteries each having a plurality of series-connected battery cells, comprising: a plurality of battery controllers that are connected to the assembled batteries and connected to each other to monitor statuses of the assembled batteries, wherein each of the plurality of battery controllers includes: a controller; a first communication circuit that communicates with another battery controller connected adjacent to the battery controller; a second communication circuit that communicates with yet another battery controller connected adjacent to the battery controller; a power circuit that receives a power supply from the assembled battery and generates a power for the controller and for the second communication circuit of the battery controller; a first insulating unit that insulates the controller and the first communication circuit; and a second insulating unit that insulates the controller and the second communication circuit, wherein the first communication circuit of the -30 -battery controller and the second communication circuit of the another battery controller are connected to each other.
2. The battery control system according to claim 1, wherein the power circuit insulates generated power for the controller from generated power for the second communication circuit.
3. The battery control system according to claim 1, wherein each of the plurality of battery controllers includes a relay circuit that controls ON/OFF of a power supply of the power circuit; and the relay circuit is ON/OFF controlled by the second communication circuit of the battery controller connected adjacent to the first communication circuit.
4. The battery control system according to claim 3, wherein the first communication circuit of the battery controller that is arranged at the farthest end of the battery control system is connected to a main controller, and a power is turned on in sequence from the relay circuit of the battery controller nearest the main controller side to the relay circuit of the battery controller farther therefrom.
5. The battery control system according to claim 1, wherein -31 -a power supply of the first communication circuit is supplied by a power circuit of the battery controller connected adjacent to the first communication circuit.
6. The battery control system according to claim 5, wherein the first communication circuit and a negative terminal of the assembled battery connected to the battery controller are connected by a wiring line, and a voltage of the first communication circuit and another voltage of the negative terminal of the assembled battery connected to the battery controller are the same as each other.
7. The battery control system according to claim 2, wherein an intermediate voltage between a positive terminal and negative terminal of the assembled battery connected to the battery controller is set to a voltage of the controller.
8. The battery control system according to claim 1, further comprising: a switch that grounds the negative terminal of each assembled battery, wherein by switching over the switch, a voltage of the communication line that connects the adjacent battery controllers is equal to the ground voltage.
9. A battery system comprising: -32 -a battery having a plurality of connected assembled batteries each having a plurality of series-connected battery cells; a plurality of battery controllers that are each connected to the assembled batteries and connected to each other to monitor statuses of the assembled batteries; and a main controller located at one end of a battery controller group in which the plurality of battery controllers are connected together via communication lines, wherein each of the battery controllers includes: a controller; a first communication circuit that communicates with the battery controller connected together on the main controller side; a second communication circuit that communicates with the battery controller connected together on the other side; a power circuit that receives a power supply from the assembled battery and supplies a power to the controller and second communication circuit of the battery controller; a first insulating unit that insulates the controller and the first communication circuit; a second insulating unit that insulates the controller and the second communication circuit; and a wiring line that connects the first -33 -communication circuit and a negative terminal of the assembled battery connected to the battery controller and in which one voltage of the first communication circuit and another voltage of the negative terminal of the assembled battery connected to the battery controller are the same as each other.
10. A battery system comprising: a battery having a plurality of parallel-connected serial blocks each having a plurality of series-connected assembled batteries each having a plurality of series-connected battery cells; a plurality of battery controllers that are each connected to the assembled batteries and connected to each other to monitor the assembled batteries, the plurality of battery controllers being communicably connected together in each serial block; and a main controller that is communicably connected to the battery controller located at one end in chain together, wherein each of the battery controllers includes: a controller; a first communication circuit that communicates with the adjacent battery controller connected together on a side near the main controller; a second communication circuit that communicates with the adjacent battery controller connected together on a side far from the main controller; and -34 -a power circuit that receives a power supply from the assembled battery and generates a power supply for driving the controller and second communication circuit of the battery controller, wherein: the first communication circuit is connected together to the second communication circuit of the adjacent battery controller.
11. A battery system comprising: a battery having a plurality of parallel-connected serial blocks each having a plurality of series-connected assembled batteries each having a plurality of series-connected battery cells; a plurality of battery controllers that are each connected to the assembled batteries and connected to each other to monitor the assembled batteries, the plurality of battery controllers being communicably connected together; and a main controller that is communicably connected to the battery controller located at one end in chain together, wherein each of the battery controllers includes: a controller; a first communication circuit that communicates with the adjacent battery controller connected together on a side near the main controller; a second communication circuit that communicates with the adjacent battery controller connected together on a side far from the main -35 -controller; and a power circuit that receives a power supply from the assembled battery and generates a power supply for driving the controller and second communication circuit of the battery controller, wherein: the first communication circuit is connected together to the second communication circuit of the adjacent battery controller.
12. A battery control system substantially as herein described with reference to and as illustrated in Figs 1 to 3, or Figs 4 and 5, or Figs 6 and 7, or Figs 8 and 9 of the accompanying drawings.
13. A battery system substantially as herein described with reference to and as illustrated with reference to and as illustrated in any of Figs 10 to 12 of the accompanying drawings.