JP6901989B2 - Battery monitoring device, battery monitoring system, and battery monitoring method - Google Patents

Description

The disclosed embodiments relate to battery monitoring devices, battery monitoring systems, and battery monitoring methods.

Conventionally, a plurality of battery devices having a relay for connecting the battery and the load and a precharge relay for preventing the inrush current from the battery to the load at startup are provided, and each battery device is connected in parallel to the load to load. There is a power supply device that supplies electric power to (see, for example, Patent Document 1).

At startup, the battery device first turns on the precharge relay, precharges the capacity component of the load by connecting the battery and the load via a resistor, and then turns on the relay to connect the battery and the load. By doing so, the inrush current from the battery to the load is prevented from flowing in. In such a battery device, it is common to perform a failure diagnosis of each relay and a precharge relay at the time of starting.

Japanese Unexamined Patent Publication No. 2014-93806

However, if the failure diagnosis of all the precharge relays provided in the plurality of battery devices is performed, the time required for the failure diagnosis increases. One aspect of the embodiment is made in view of the above, and an object of the present invention is to provide a battery monitoring device, a battery monitoring system, and a battery monitoring method capable of shortening the time required for failure diagnosis.

The battery monitoring device according to one aspect of the embodiment is provided in a plurality of battery devices including a relay for connecting the battery and the load and a precharge relay for preventing the inflow of the inrush current from the battery to the load. It is a battery monitoring device that monitors the state of the battery device, and includes a diagnostic unit. The diagnostic unit is limited to the case where the battery device to be monitored is the battery device that is first connected to the load among the plurality of battery devices that are connected in parallel with the load in a predetermined connection order at startup. Diagnose the failure of the precharge relay.

The battery monitoring device, the battery monitoring system, and the battery monitoring method according to one aspect of the embodiment can shorten the time required for failure diagnosis.

FIG. 1 is an explanatory diagram showing an example of the configuration of the battery monitoring system according to the embodiment. FIG. 2 is an explanatory diagram of communication between BMS performed during the failure diagnosis according to the embodiment. FIG. 3 is an explanatory diagram showing an example of the operation timings of the positive relay, the negative relay, and the P relay at the time of activation according to the embodiment. FIG. 4 is a flowchart showing an example of processing executed by the diagnosis unit of the master BMS according to the embodiment.

Hereinafter, embodiments of the battery monitoring device, the battery monitoring system, and the battery monitoring method will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments shown below. Here, a battery monitoring system that monitors the state of a battery device that supplies electric power to a motor that drives a vehicle will be described as an example. FIG. 1 is an explanatory diagram showing an example of the configuration of the battery monitoring system 100 according to the embodiment.

As shown in FIG. 1, the battery monitoring system 100 includes a first pack 10, a second pack 20, and a third pack 30. The first pack 10, the second pack 20, and the third pack 30 are battery devices, which are connected in parallel with the load 4 to supply electric power to the load 4. The load 4 is a motor for traveling the vehicle.

Here, a case where the battery monitoring system 100 includes three battery devices of the first pack 10, the second pack 20, and the third pack 30 will be described as an example, but the number of battery devices is plural. If the number is 2, the number may be two, or four or more.

The first pack 10 includes an assembled battery 11 in which a plurality of batteries are connected in series. Further, the first pack 10 includes a positive electrode side relay (hereinafter, referred to as “positive relay 12”) that connects the positive electrode of the assembled battery 11 and the positive electrode of the load 4, and the negative electrode of the assembled battery 11 and the negative electrode of the load 4. It is provided with a negative electrode side relay (hereinafter, referred to as “negative relay 13”) for connecting the above.

Further, the first pack 10 includes a precharge relay (hereinafter referred to as “P relay 14”) for preventing the inrush current from flowing into the load 4 from the assembled battery 11. The P relay 14 is connected in parallel with the positive relay 12 via the resistor 15.

Further, the first pack 10 is provided with a master BMS (Battery Management System) 16. The master BMS 16 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various circuits.

The master BMS 16 is a battery monitoring device that monitors the state of the first pack 10, and includes a diagnostic unit 17 that functions by the CPU executing a program stored in the ROM using the RAM as a work area.

The master BMS 16 monitors the voltage state of the assembled battery 11 and also controls to switch the positive relay 12, the negative relay 13, and the P relay 14 on / off. The diagnosis unit 17 diagnoses the failure of the positive relay 12, the negative relay 13, and the P relay 14.

The diagnostic unit 17 included in the master BMS 16 may be composed of hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

The second pack 20 includes an assembled battery 21 in which a plurality of batteries are connected in series. Further, the second pack 20 includes a positive electrode side relay (hereinafter, referred to as “positive relay 22”) that connects the positive electrode of the assembled battery 21 and the positive electrode of the load 4, and the negative electrode of the assembled battery 21 and the negative electrode of the load 4. It is provided with a negative electrode side relay (hereinafter, referred to as “negative relay 23”) for connecting the above.

Further, the second pack 20 includes a precharge relay (hereinafter referred to as “P relay 24”) for preventing the inrush current from flowing into the load 4 from the assembled battery 21. The P relay 24 is connected in parallel with the positive relay 22 via the resistor 25.

Further, the second pack 20 is provided with the first slave BMS26. The first slave BMS 26 includes a microcomputer having a CPU, ROM, RAM, and the like, and various circuits. The first slave BMS 26 is a battery monitoring device that monitors the state of the second pack 20, and includes a diagnostic unit 27 that functions by the CPU executing a program stored in the ROM using the RAM as a work area. ..

The first slave BMS 26 monitors the voltage state of the assembled battery 21, and also controls to switch the positive relay 22, the negative relay 23, and the P relay 24 on / off. The diagnosis unit 27 performs failure diagnosis of the positive relay 22, the negative relay 23, and the P relay 24. The diagnostic unit 27 included in the first slave BMS 26 may be composed of hardware such as an ASIC or FPGA.

The third pack 30 includes an assembled battery 31 in which a plurality of batteries are connected in series. Further, the third pack 30 includes a positive electrode side relay (hereinafter, referred to as “positive relay 32”) that connects the positive electrode of the assembled battery 31 and the positive electrode of the load 4, and the negative electrode of the assembled battery 31 and the negative electrode of the load 4. It is provided with a negative electrode side relay (hereinafter, referred to as “negative relay 33”) for connecting the above.

Further, the third pack 30 includes a precharge relay (hereinafter referred to as “P relay 34”) for preventing the inrush current from flowing into the load 4 from the assembled battery 31. The P relay 34 is connected in parallel with the positive relay 32 via the resistor 35.

Further, the third pack 30 is provided with a second slave BMS 36. The second slave BMS 36 includes a microcomputer having a CPU, ROM, RAM, and the like, and various circuits. The second slave BMS 36 is a battery monitoring device that monitors the state of the third pack 30, and includes a diagnostic unit 37 that functions by the CPU executing a program stored in the ROM using the RAM as a work area. ..

The second slave BMS 36 monitors the voltage state of the assembled battery 31 and also controls to switch the positive relay 32, the negative relay 33, and the P relay 34 on / off. The diagnosis unit 37 diagnoses the failure of the positive relay 32, the negative relay 33, and the P relay 34. The diagnostic unit 37 included in the second slave BMS 36 may be composed of hardware such as an ASIC or FPGA.

In the following, when a specific pack is not referred to among the first pack 10, the second pack 20, and the third pack 30, it may be simply referred to as a pack. Further, in the following, when a specific positive relay is not pointed out among the three positive relays 12, 22 and 32, it may be simply described as a positive relay.

Similarly, when the three negative relays 13, 23, 33 do not refer to a specific negative relay, it is simply described as a negative relay, and the three P relays 14, 24, 34 are similarly described as negative relays. , When not referring to a specific P relay, it may be simply described as a P relay.

The master BMS 16, the first slave BMS26, and the second slave BMS36 are connected by a CAN (Controller Area Network) communication line shown by a thick dotted line in FIG. 1, and can transmit and receive various information to and from each other via the CAN communication line. ..

For example, the master BMS 16 transmits information including a command to start the failure diagnosis to the first slave BMS 26 and the second slave BMS 36. Further, the master BMS 16 transmits information including a command to start power supply to the load 4 to the first slave BMS 26 and the second slave BMS 36.

On the other hand, the first slave BMS 26 and the second slave BMS 36 transmit information including, for example, a failure diagnosis result and an operation result according to a command from the master BMS 16 to the master BMS 16.

Further, the first slave BMS 26 transmits information indicating the voltage of the assembled battery 21 to the master BMS 16 at a predetermined cycle. The second slave BMS 36 transmits information indicating the voltage of the assembled battery 31 to the master BMS 16 at a predetermined cycle.

Further, the master BMS 16 and the vehicle control unit 5 are connected by a CAN communication line shown by a thick dotted line in FIG. 1, and various information can be transmitted and received to each other via the CAN communication line.

For example, when the master BMS 16 receives a start signal and starts up, the master BMS 16 performs a failure diagnosis of the first pack 10 and a failure diagnosis of the second pack 20 and the third pack 30, and includes the result of the failure diagnosis. Information is transmitted to the vehicle control unit 5. Further, the master BMS 16 transmits information or the like indicating the average voltage of the assembled batteries 11, 21, 31 to the vehicle control unit 5 at a predetermined cycle.

The vehicle control unit 5 is a control device that controls the entire vehicle, and includes a microcomputer having a CPU, ROM, RAM, and various circuits. The vehicle control unit 5 controls the operation of the load 4 by outputting a control signal for rotating the motor to the load 4 at a rotation speed corresponding to the operation of the driver of the vehicle, for example.

Further, the vehicle control unit 5 provides information indicating that any one of the positive relays 12, 22, 32, the negative relays 13, 23, 33, and the P relays 14, 24, 34 has failed from the master BMS 16, for example. When receiving, the warning light is turned on to notify the user of the failure.

In such a battery monitoring system 100, when the ignition switch (hereinafter referred to as “IG”) of the vehicle is turned on and activated, the failure diagnosis of the first pack 10, the second pack 20, and the third pack 30 is performed. ..

When performing a failure diagnosis of each pack, the master BMS 16 first determines the connection order of the packs to be connected to the load 4 in order. At this time, the master BMS 16 calculates, for example, the average voltage of the assembled batteries 11, 21, 31 of the first pack 10, the second pack 20, and the third pack 30, and connects the packs in the order in which the voltages are close to the average voltage. Determine the connection order.

Then, the master BMS 16 performs failure diagnosis of the positive relay and the negative relay of each pack in the order of coming to each pack in the same order as the determined connection order. At this time, when the pack connected to the load 4 is the first pack 10, the master BMS 16 performs a failure diagnosis of the positive relay 12 and the negative relay 13 and then the second pack in the order of connection. The failure diagnosis of the positive relay and the negative relay of the 20th and the 3rd pack 30 is performed.

Further, when the pack first connected to the load 4 is the first pack 10 or the second pack 20, the master BMS 16 causes a failure diagnosis of the positive relay and the negative relay of the pack connected to the load 4 first. ..

After that, when the pack connected to the load 4 secondly is the first pack 10, the master BMS 16 performs a failure diagnosis of the positive relay 12 and the negative relay 13, and then performs a failure diagnosis of the positive relay and the negative relay of the remaining packs. Have a failure diagnosis performed.

Further, when the pack connected to the load 4 second is not the first pack 10, the master BMS 16 relays the positive relay to the pack of the second pack 20 and the third pack 30 for which the failure diagnosis has not been performed. Have the negative relay fault diagnosed. After that, the master BMS 16 performs a failure diagnosis of the positive relay 12 and the negative relay 13.

After that, the master BMS 16 executes a failure diagnosis of the P relay before sequentially connecting each pack to the load 4. At this time, in the battery monitoring system 100, even if all three P relays 14, 24, and 34 are not diagnosed, the load 4 is as long as the P relay of the pack connected to the load 4 is normal. No inrush current flows.

For example, if the P relay of the pack connected to the load 4 is not failed first and the P relay of the pack connected to the load 4 is failed secondly, the first pack is referred to as the load 4. At the time of connection, the P relay can be turned on to precharge the capacitance component of the load 4.

As a result, the load 4 has already been precharged when the second pack is connected, so that the P relay of the pack connected to the second load 4 has failed and is stuck on. However, the inrush current does not flow into the load 4. This is also the case when the P relay of the pack connected to the load 4 thirdly fails.

Therefore, the master BMS 16 executes the failure diagnosis of the P relay only for the pack connected to the load 4 first after the failure diagnosis of all the positive relays and the negative relays is completed, and performs the failure diagnosis of the other P relays. Instead, each pack and the load 4 are connected in the previously determined connection order.

As a result, the battery monitoring system 100 prevents the inrush current from flowing into the load 4 at the time of startup, and omits the failure diagnosis of the P relay included in the pack other than the pack connected to the load 4 first. The time required for failure diagnosis can be shortened.

Next, an example of communication between BMS during the failure diagnosis will be described with reference to FIG. FIG. 2 is an explanatory diagram of communication between BMS during the failure diagnosis according to the embodiment. Here, a case where the connection order is determined by the master BMS 16 so as to connect to the load 4 in the order of the first pack 10, the second pack 20, and the third pack 30 will be described as an example.

The block described as "negative" shown in FIG. 2 indicates the period of failure diagnosis performed by operating the negative relay, and the block described as "positive" indicates the failure performed by operating the positive relay. Shows the duration of diagnosis.

Further, the block described as "P" indicates the period of failure diagnosis performed by operating the P relay, and the block described as "precharge" indicates the period during which the capacitance component of the load 4 is being precharged. Is shown.

Further, the block described as "load connection" indicates the period of connection operation for connecting the pack to the load 4. The operation of each positive relay, each negative relay, and each P relay during the failure diagnosis, and the content of the failure diagnosis will be described in detail with reference to FIG.

When the first pack 10, the second pack 20, and the third pack 30 are connected to the load 4 in this order, the master BMS 16 operates the negative relay 13 and the positive relay 12 as shown in FIG. Perform failure diagnosis continuously. Then, the master BMS 16 transmits information including a command to start the failure diagnosis to the first slave BMS 26 (step S1).

Upon receiving the information including the command to start the failure diagnosis, the first slave BMS 26 continuously performs the failure diagnosis for operating the negative relay 23 and the failure diagnosis for operating the positive relay 22, and includes the result of the failure diagnosis. Information is transmitted to the master BMS 16 (step S2).

When the master BMS 16 receives the information including the failure result from the first slave BMS 26, the master BMS 16 transmits the information including the command to start the failure diagnosis to the second slave BMS 36 (step S3).

When the second slave BMS 36 receives the information including the command to start the failure diagnosis, the second slave BMS 36 continuously performs the failure diagnosis for operating the negative relay 33 and the failure diagnosis for operating the positive relay 32, and includes the result of the failure diagnosis. Information is transmitted to the master BMS 16 (step S4).

When the master BMS 16 receives the information including the failure result from the second slave BMS 36, the master BMS 16 operates the P relay 14 to precharge the capacitance component of the load 4 and connects the first pack 10 to the load 4. At this time, the master BMS 16 performs a failure diagnosis of the P relay 14. Then, the master BMS 16 transmits information including a connection command with the load 4 to the first slave BMS 26 (step S5).

Upon receiving the connection command with the load 4, the first slave BMS 26 connects the second pack 20 with the load 4 and transmits information including an operation result indicating that fact to the master BMS 16 (step S6). When the master BMS 16 receives the information including the operation result from the first slave BMS 26, the master BMS 16 transmits the information including the connection command with the load 4 to the second slave BMS 36 (step S7).

When the second slave BMS 36 receives the information including the connection command with the load 4, the second slave BMS 36 connects the third pack 30 with the load 4 and transmits the information including the operation result indicating to that effect to the master BMS 16 (step S8).

As described above, in the battery monitoring system 100, the master BMS 16, the first slave BMS 26, and the second slave BMS 36 communicate each time the failure diagnosis for operating the negative relay and the failure diagnosis for operating the positive relay are continuously performed. Do.

As a result, in the battery monitoring system 100, the master BMS 16, the first slave BMS 26, and the second slave BMS 36 operate the negative relays in order, and then operate the positive relays in order to perform failure diagnosis. The number of communications can be reduced.

Specifically, when the master BMS 16, the first slave BMS 26, and the second slave BMS 36 operate the negative relays in order and then operate the positive relays in order to perform failure diagnosis, each time the negative relays are operated. And it is necessary to communicate every time the positive relay is operated.

In such a case, the master BMS 16 operates the negative relay, the master BMS 16 transmits the operation command of the negative relay to the first slave BMS 26 (first communication), and the first slave BMS 26 transmits the operation result of the negative relay to the master BMS 16. (Second communication).

Subsequently, the master BMS 16 transmits a negative relay operation command to the second slave BMS 36 (third communication), and the second slave BMS 36 transmits the negative relay operation result to the master BMS 16 (fourth communication).

After that, the master BMS 16 operates the positive relay, the operation command of the positive relay is transmitted from the master BMS 16 to the first slave BMS 26 (fifth communication), and the operation result of the negative relay is transmitted from the first slave BMS 26 to the master BMS 16 ( 6th communication).

Subsequently, the master BMS 16 transmits the operation command of the positive relay to the second slave BMS 36 (7th communication), and the second slave BMS 36 transmits the operation result of the positive relay to the master BMS 16 (8th communication). In this way, a total of eight communications are required.

On the other hand, in the battery monitoring system 100, as shown in FIG. 2, the failure diagnosis for operating the negative relay and the failure diagnosis for operating the positive relay can be completed in the four communications of steps S1 to S4. it can.

Further, in the battery monitoring system 100, a failure diagnosis for operating the negative relay and a failure diagnosis for operating the positive relay are performed in the same order as the connection order with the load 4 determined by the master BMS 16 and in the order in which the negative relays are turned to each pack. , Connect each pack to the load 4 in the determined connection order.

In the example shown in FIG. 2, the master BMS 16 performs failure diagnosis and connection with the load 4 in the order of the first pack 10, the second pack 20, and the third pack 30. Thereby, the master BMS 16 can realize the control of the order of performing the failure diagnosis of each pack and the order of connecting each pack with the load 4 by a simple process.

Next, an example of the operation of each pack at startup will be described with reference to FIGS. 3 and 1. FIG. 3 is an explanatory diagram showing an example of the operation timings of the positive relay, the negative relay, and the P relay at the time of activation according to the embodiment. Here, as in the case shown in FIG. 2, a case where the load 4 is connected in the order of the first pack 10, the second pack 20, and the third pack 30 will be described as an example.

When the master BMS 16 decides to connect to the load 4 in the order of the first pack 10, the second pack 20, and the third pack 30, first, the positive relay 12 and P of the first pack 10 are connected during the period from time t1 to time t2. The negative relay 13 is turned on with the relay 14 turned off. At this time, if the positive relay 12 and the P relay 14 are not fixed on, the potential difference between the positive electrode and the negative electrode of the first pack 10 should be “0”.

Therefore, if the potential difference between the positive electrode and the negative electrode of the first pack 10 is "0", the diagnostic unit 17 of the master BMS 16 diagnoses that the positive relay 12 and the P relay 14 are not fixed on. Further, when the potential difference between the positive electrode and the negative electrode of the first pack 10 is not "0", the diagnostic unit 17 diagnoses that the positive relay 12 or the P relay 14 is stuck on and is out of order.

The diagnostic unit 17 diagnoses that the positive relay 12 is on and stuck when the potential difference between the positive electrode and the negative electrode of the first pack 10 is substantially the same as the voltage of the assembled battery 11, and the voltage of the assembled battery 11 If it is lower than, it can be diagnosed that the P relay 14 is stuck on.

After that, the master BMS 16 turns on the positive relay 12 with the negative relay 13 and the P relay 14 of the first pack 10 turned off during the period from time t2 to time t3. At this time, if the negative relay 13 is not fixed on, the potential difference between the positive electrode and the negative electrode of the first pack 10 should be “0”.

Therefore, if the potential difference between the positive electrode and the negative electrode of the first pack 10 is "0", the diagnostic unit 17 diagnoses that the negative relay 13 is not stuck on. Further, when the potential difference between the positive electrode and the negative electrode of the first pack 10 is not "0", the diagnostic unit 17 diagnoses that the negative relay 13 is stuck on and is out of order.

Subsequently, the first slave BMS 26 turns on the negative relay 23 with the positive relay 22 and the P relay 24 of the second pack 20 turned off during the period from time t3 to time t4. At this time, if the positive relay 22 and the P relay 24 are not fixed on, the potential difference between the positive electrode and the negative electrode of the second pack 20 should be “0”.

Therefore, the diagnosis unit 27 of the first slave BMS 26 diagnoses that the positive relay 22 and the P relay 24 are not fixed on if the potential difference between the positive electrode and the negative electrode of the second pack 20 is “0”. Further, when the potential difference between the positive electrode and the negative electrode of the second pack 20 is not "0", the diagnostic unit 27 diagnoses that the positive relay 22 or the P relay 24 is stuck on and is out of order.

The diagnostic unit 27 diagnoses that the positive relay 22 is stuck on when the potential difference between the positive electrode and the negative electrode of the second pack 20 is substantially the same as the voltage of the assembled battery 21, and the voltage of the assembled battery 21. If it is lower than, it can be diagnosed that the P relay 24 is stuck on.

After that, the first slave BMS 26 turns on the positive relay 22 with the negative relay 23 and the P relay 24 of the second pack 20 turned off during the period from time t4 to time t5. At this time, if the negative relay 23 is not fixed on, the potential difference between the positive electrode and the negative electrode of the second pack 20 should be “0”.

Therefore, if the potential difference between the positive electrode and the negative electrode of the second pack 20 is "0", the diagnostic unit 27 diagnoses that the negative relay 23 is not stuck on. Further, when the potential difference between the positive electrode and the negative electrode of the second pack 20 is not "0", the diagnosis unit 27 diagnoses that the negative relay 23 is stuck on and is out of order.

Subsequently, the second slave BMS 36 turns on the negative relay 33 with the positive relay 32 and the P relay 34 of the third pack 30 turned off during the period from time t5 to time t6. At this time, if the positive relay 32 and the P relay 34 are not fixed on, the potential difference between the positive electrode and the negative electrode of the third pack 30 should be “0”.

Therefore, the diagnostic unit 37 of the second slave BMS 36 diagnoses that the positive relay 32 and the P relay 34 are not fixed on if the potential difference between the positive electrode and the negative electrode of the third pack 30 is “0”. Further, when the potential difference between the positive electrode and the negative electrode of the third pack 30 is not "0", the diagnostic unit 37 diagnoses that the positive relay 32 or the P relay 34 is stuck on and is out of order.

The diagnostic unit 37 diagnoses that the positive relay 32 is on and stuck when the potential difference between the positive electrode and the negative electrode of the third pack 30 is substantially the same as the voltage of the assembled battery 31, and the voltage of the assembled battery 31. If it is lower than, it can be diagnosed that the P relay 34 is stuck on.

After that, the second slave BMS 36 turns on the positive relay 32 with the negative relay 33 and the P relay 34 of the third pack 30 turned off during the period from time t6 to time t7. At this time, if the negative relay 33 is not fixed on, the potential difference between the positive electrode and the negative electrode of the third pack 30 should be “0”.

Therefore, if the potential difference between the positive electrode and the negative electrode of the third pack 30 is "0", the diagnostic unit 37 diagnoses that the negative relay 33 is not stuck on. Further, when the potential difference between the positive electrode and the negative electrode of the third pack 30 is not "0", the diagnostic unit 37 diagnoses that the negative relay 33 is stuck on and is out of order.

With the operations up to this point, the failure diagnosis of the positive relays 12, 22, 32, the negative relays 13, 23, 33, and the P relays 14, 24, 34 is completed. Next, since the master BMS 16 is the pack in which the first pack 10 to be monitored is the pack that is first connected to the load 4, the failure diagnosis of the P relay 14 of the first pack 10 is performed.

At this time, the master BMS 16 performs a failure diagnosis of the P relay 14 by utilizing the operation of precharging the capacitance component of the load 4 required when the load 4 and the pack are first connected. As a result, the master BMS 16 can omit the process of operating the P relay 14 only for the failure diagnosis of the P relay 14, so that the time required for the failure diagnosis can be shortened.

Specifically, the diagnostic unit 17 of the master BMS 16 turns on the negative relay 13 at time t7, and then turns on the P relay 14 at time t8. As a result, the electric power whose voltage is lowered by the resistor 15 is supplied to the load 4 from the assembled battery 11 via the P relay 14, and the capacitance component of the load 4 is precharged.

At this time, when the potential difference between the positive electrode and the negative electrode of the first pack 10 is "0", the diagnostic unit 17 diagnoses that the P relay 14 is stuck off and is out of order. Further, in the diagnostic unit 17, if the potential difference between the positive electrode and the negative electrode of the first pack 10 is a predetermined voltage obtained by lowering the voltage of the assembled battery 11 by the resistor 15, the P relay 14 is fixed off. Diagnose that it is operating normally.

Then, when the diagnostic unit 17 determines that the P relay 14 is normal, the master BMS 16 turns on the positive relay 12 at time t9 to connect the assembled battery 11 and the load 4. After that, the first slave BMS 26 turns on the negative relay 23 at time t10 and turns on the positive relay 22 at time t11 to connect the assembled battery 21 and the load 4.

Subsequently, the second slave BMS 36 turns on the negative relay 33 at time t11 and turns on the positive relay 32 at time t12 to connect the assembled battery 31 and the load 4. As a result, the connection between the first pack 10, the second pack 20, and the third pack 30 and the load 4 is completed.

As described above, the precharge of the load 4 is already completed when the assembled battery 21 of the second pack 20 is connected to the load 4 and when the assembled battery 31 of the third pack 30 is connected to the load 4. doing. Therefore, the inrush current does not flow into the load 4.

Next, with reference to FIG. 4, a process executed by the diagnosis unit 17 of the master BMS 16 will be described. FIG. 4 is a flowchart showing an example of processing executed by the diagnosis unit 17 of the master BMS 16 according to the embodiment.

The diagnosis unit 17 performs the process shown in FIG. 4 when the IG is turned on. Specifically, as shown in FIG. 4, the diagnostic unit 17 first acquires the voltages of the assembled batteries 11, 21, and 31 of the first pack 10, the second pack 20, and the third pack 30 (step). S101).

Subsequently, the diagnostic unit 17 determines the connection order of the packs (first pack 10, second pack 20, third pack 30) to be connected to the load 4 based on the voltage of each assembled battery 11, 21, 31 (1st pack 10, 2nd pack 20, 3rd pack 30). Step S102).

Then, the diagnosis unit 17 executes the relay diagnosis of the pack that first connects to the load 4 in the determined connection order (step S103). At this time, when the first pack to be connected is the first pack 10, the diagnosis unit 17 performs relay diagnosis of the positive relay 12 and the negative relay 13 of the first pack 10.

Further, when the pack to be connected first is the second pack 20, the diagnosis unit 17 causes the diagnosis unit 27 of the second pack 20 to perform a failure diagnosis of the positive relay 22 and the negative relay 23, and acquires the diagnosis result. Further, when the pack to be connected first is the third pack 30, the diagnosis unit 17 causes the diagnosis unit 37 of the third pack 30 to perform a failure diagnosis of the positive relay 32 and the negative relay 33, and acquires the diagnosis result.

Subsequently, the diagnostic unit 17 then executes relay diagnosis of the pack connected to the load 4 (step S104). At this time, when the pack to be connected next is the first pack 10, the diagnosis unit 17 performs relay diagnosis of the positive relay 12 and the negative relay 13 of the first pack 10.

Further, when the pack to be connected next is the second pack 20, the diagnosis unit 17 causes the diagnosis unit 27 of the second pack 20 to perform a failure diagnosis of the positive relay 22 and the negative relay 23, and acquires the diagnosis result. Further, when the pack to be connected next is the third pack 30, the diagnosis unit 17 causes the diagnosis unit 37 of the third pack 30 to perform a failure diagnosis of the positive relay 32 and the negative relay 33, and acquires the diagnosis result.

After that, the diagnosis unit 17 determines whether or not there is a pack for which the relay has not been diagnosed (step S105). Then, when the diagnosis unit 17 determines that there is an undiagnosed pack (step S105, Yes), the diagnosis unit 17 shifts the process to step S104.

Further, when the diagnosis unit 17 determines that there is no undiagnosed pack (step S105, No), it determines whether or not there is a failed relay (step S106). When the diagnosis unit 17 determines that there is a failed relay (step S106, Yes), the diagnostic unit 17 excludes the pack containing the failed relay from the connection target (step S107), and shifts the process to step S108.

Further, when the diagnosis unit 17 determines that there is no failed relay (step S106, No), the diagnosis unit 17 executes the P relay diagnosis of the pack to be connected first (step S108). At this time, when the pack to be connected first is the first pack 10, the diagnosis unit 17 performs relay diagnosis of the P relay 14 of the first pack 10.

Further, when the pack to be connected first is the second pack 20, the diagnosis unit 17 causes the diagnosis unit 27 of the second pack 20 to perform a failure diagnosis of the P relay 24 and obtains a diagnosis result. Further, when the first pack to be connected is the third pack 30, the diagnosis unit 17 causes the diagnosis unit 37 of the third pack 30 to perform a failure diagnosis of the P relay 34 and obtains a diagnosis result.

Subsequently, the diagnostic unit 17 first determines whether or not the P relay of the pack connected to the load 4 is normal (step S109), and if it determines that the P relay is not normal (step S109, No), vehicle control. A failure notification is given to the unit 5 (step S110), and the process ends.

Further, when the diagnostic unit 17 determines that the P relay is normal (step S109, Yes), the pack and the load 4 are sequentially connected in the connection order determined in step S102 (step S111), and the IG is turned off. It is determined whether or not it is (step S112).

Then, when the diagnosis unit 17 determines that the IG is not turned off (steps S112, No), the diagnosis unit 17 repeats the determination process of step S112 until the IG is turned off. If the diagnostic unit 17 determines that the IG has been turned off (step S112, Yes), the diagnostic unit 17 turns off all relays (step S113) and ends the process.

As described above, each pack according to the embodiment includes relays (positive relay and negative relay) for connecting the assembled battery and the load, and a P relay for preventing the inrush current from flowing into the load from the assembled battery. Each BMS (master BMS, first slave BMS, second slave BMS) according to the embodiment is provided in each pack and is a battery monitoring device for monitoring the state of the pack.

Each BMS diagnoses the failure of the P relay only when the pack to be monitored is the pack that is connected to the load first among the multiple packs that are connected in parallel with the load in a predetermined connection order at startup. It has a part. As a result, in the BMS according to the embodiment, when the pack to be monitored is not the pack to be connected to the load first, the failure diagnosis of the P relay can be omitted, so that the time required for the failure diagnosis can be shortened. it can.

Further, the pack according to the embodiment includes a positive relay that connects the positive electrode of the assembled battery and the positive electrode of the load, and a negative relay that connects the negative electrode of the assembled battery and the negative electrode of the load. The failure diagnosis and the failure diagnosis of the positive relay are performed continuously. As a result, each BMS can shorten the time required for the failure diagnosis by reducing the number of communications for transmitting and receiving information to and from each other during the failure diagnosis.

Further, the diagnostic unit according to the embodiment operates the P relay that turns on the P relay and precharges the capacitance component of the load before turning on the positive relay in the state where the negative relay of the pack to be monitored is turned on. The failure diagnosis of the P relay is performed based on.

In this way, since the diagnostic unit diagnoses the failure of the P relay by using the precharge operation of the load that is indispensable at the time of startup, it is possible to omit the process of operating the P relay only for the failure diagnosis of the P relay. Therefore, the time required for failure diagnosis can be shortened.

Further, the diagnostic unit according to the embodiment diagnoses the failure of the positive relay and the negative relay of the pack to be monitored in the order in which each pack and the load are connected to each pack in the same order as the predetermined connection order. Do. As a result, the diagnostic unit can control the order in which the failure diagnosis of each pack is performed and the order in which each pack is connected to the load by a simple process.

In the above-described embodiment, the battery monitoring system that monitors the state of the battery device that supplies electric power to the motor that drives the vehicle has been described as an example. However, the battery monitoring system according to the embodiment is HEMS (Home Energy). It is also possible to monitor the status of the battery device provided in any power supply system such as Management System).

Further, in the above-described embodiment, the BMS of each pack is the positive relay and the negative relay of the pack to be monitored in the order in which each pack comes to each pack in the same order as the predetermined connection order in which each pack is connected to the load. A failure diagnosis was performed, but this is just an example.

If the BMS of each pack can perform the failure diagnosis of the P relay only when the pack to be monitored is the pack to be connected to the load first, the failure diagnosis of the positive relay and the negative relay performed before that can be performed. , You may do it in any order.

Further effects and variations can be easily derived by those skilled in the art. For this reason, the broader aspects of the invention are not limited to the particular details and representative embodiments expressed and described above. Therefore, various modifications can be made without departing from the spirit or scope of the general concept of the invention as defined by the appended claims and their equivalents.

100 Battery monitoring system 4 Load 5 Vehicle control unit 10 1st pack 20 2nd pack 30 3rd pack 11,21,31 assembled batteries 12,22,32 Positive relay 13,23,33 Negative relay 14,24,34 P relay 15, 25, 35 Resistance 17, 27, 37 Diagnostic Department 16 Master BMS
26 1st slave BMS
36 Second slave BMS

Claims (6)

A battery monitoring device provided in a plurality of battery devices including a relay for connecting the battery and the load and a precharge relay for preventing the inrush current from flowing from the battery to the load, and monitoring the state of the battery device. There,
Of the plurality of battery devices that are connected in parallel with the load in a predetermined connection order at startup, only when the battery device to be monitored becomes the battery device that is first connected to the load, the precharge relay A battery monitoring device characterized by having a diagnostic unit for fault diagnosis. The battery device is
A positive electrode side relay that connects the positive electrode of the battery and the positive electrode of the load, and a negative electrode side relay that connects the negative electrode of the battery and the negative electrode of the load are provided.
The diagnostic unit
The battery monitoring device according to claim 1, wherein the failure diagnosis of the negative electrode side relay and the failure diagnosis of the positive electrode side relay are continuously performed. The diagnostic unit
The precharge relay that turns on the precharge relay and precharges the capacitance component of the load before turning on the positive electrode side relay in the state where the negative electrode side relay of the battery device to be monitored is turned on. The battery monitoring device according to claim 2, wherein the failure diagnosis of the precharge relay is performed based on the operation. The diagnostic unit
2. or claim, wherein the failure diagnosis of the positive electrode side relay and the negative electrode side relay of the battery device to be monitored is performed in the order in which the battery devices are visited in the same order as the predetermined connection order. Item 3. The battery monitoring device according to item 3. A battery monitoring device provided in a plurality of battery devices including a relay for connecting the battery and the load and a precharge relay for preventing the inrush current from flowing from the battery to the load, and monitoring the state of the battery device. Prepare,
Each of the battery monitoring devices
Of the plurality of battery devices that are connected in parallel with the load in a predetermined connection order at startup, only when the battery device to be monitored becomes the battery device that is first connected to the load, the precharge relay A battery monitoring system characterized by having a diagnostic unit for fault diagnosis. A step of monitoring the state of the battery device by a battery monitoring device provided in a plurality of battery devices including a relay for connecting the battery and the load and a precharge relay for preventing the inrush current from flowing from the battery to the load. When,
Of the plurality of battery devices that are connected in parallel with the load in a predetermined connection order at startup, only when the battery device to be monitored by the battery monitoring device becomes the battery device that is first connected to the load. A battery monitoring method including a step of diagnosing a failure of the precharge relay.

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