JP6825678B2 - vehicle - Google Patents

Description

The techniques disclosed herein relate to battery devices, vehicles, battery management programs and methods of managing battery devices.

For example, a battery unit having a switching means mounted on a vehicle is known as described in Japanese Patent Application Laid-Open No. 5-205781 (Patent Document 1 below). This battery unit opens the switch means when the load on the vehicle increases and the voltage of the battery continues to decrease for a predetermined time, and disconnects the load on the vehicle from the battery to prevent over-discharging of the battery.

Further, in general, a vehicle generator for charging the battery is connected to such a battery unit in parallel with the load, and opening the switch means prevents the battery from becoming overcharged. ing.

Japanese Unexamined Patent Publication No. 5-205781

By the way, in the case of such a battery unit, if the switch means is out of order, it becomes impossible to prevent an abnormal state such as over-discharge or over-charge of the battery, so it is necessary to detect the failure of the switch means. .. Therefore, it is being studied to connect a voltage drop element in parallel with the switch means, cut off the current in the current cutoff device, and detect the voltage drop due to the voltage drop element to diagnose the failure of the current cutoff device. ..

However, if a large current exceeding the maximum allowable current of the voltage drop element flows through the voltage drop element while the current is being cut off in the current cutoff device, the voltage drop element is damaged. However, if a voltage drop element having a large maximum allowable current is used, the mounting space for the voltage drop element becomes large and the manufacturing cost increases.

This specification discloses a technique for preventing a voltage drop element from being damaged by a large current without using a voltage drop element having a large maximum allowable current.

The technology disclosed herein is parallel to a secondary battery that supplies power to a load, a current cutoff section that switches between the secondary battery and the load in an energized state and a cutoff state, and a current cutoff section. A parallel circuit having a voltage drop element that is connected and causes a voltage drop due to the flow of current, and a control unit are provided, and the control unit operates with a power supply exceeding the maximum allowable current of the voltage drop element. Is configured to execute a cutoff process for switching the current cutoff unit to the cutoff state when the current cutoff unit does not operate.

According to the technique disclosed herein, it is possible to prevent the voltage drop element from being damaged by the large current without using the voltage drop element having a large maximum allowable current.

The figure which shows the vehicle which concerns on Embodiment 1. Perspective view of battery device An exploded perspective view of the battery device Block diagram of battery device The figure which shows the current cutoff circuit Flow chart of battery protection processing Flow chart of failure diagnosis process Flow chart of prohibited processing The figure which shows the current cutoff circuit which concerns on Embodiment 2. The figure which shows the modification of the auxiliary current cutoff device Flow chart of battery protection processing Flow chart diagram of prohibited processing according to the third embodiment Flow chart of failure diagnosis process

(Outline of this embodiment)
First, the outline of the battery device, the battery management program, and the management method of the battery device disclosed in the present embodiment will be described.

The battery device disclosed in the present embodiment includes a secondary battery that supplies power to a load, a current cutoff unit that switches between the secondary battery and the load in an energized state and a cutoff state, and the current cutoff unit. The control unit includes a parallel circuit having a voltage drop element that is connected in parallel and causes a voltage drop when a current flows, and the control unit operates by supplying power exceeding the maximum allowable current of the voltage drop element. When the load does not operate, the cutoff process for switching the current cutoff unit to the cutoff state is executed.

Further, the vehicle disclosed in the present embodiment has a configuration having the battery device, the load, and a load system for controlling the operation of the load.
Further, the vehicle disclosed in the present embodiment is a vehicle having the battery device, the load, and the load system, and the load system receives the prohibition instruction to input the high load. Was configured to prohibit the operation of.

Further, the battery management program disclosed in the present embodiment includes a secondary battery that supplies power to the load, a current cutoff unit that switches between the secondary battery and the load in an energized state and a cutoff state, and the current. High that operates by supplying power exceeding the maximum allowable current of the voltage drop element to the control unit of the battery device including a parallel circuit having a voltage drop element that is connected in parallel to the cutoff unit and causes a voltage drop when a current flows. When the load does not operate, the cutoff process for switching the current cutoff unit to the cutoff state is executed.

Further, the method of managing the battery device disclosed in the present embodiment includes a secondary battery that supplies power to the load, a current cutoff device that switches between the secondary battery and the load in an energized state and a cutoff state. A method for managing a battery device including a parallel circuit having a voltage drop element that is connected in parallel to the current cutoff device and causes a voltage drop when a current flows, and supplies power exceeding the maximum allowable current of the voltage drop element. When the high load that operates in response to the response does not operate, the current cutoff device is switched to the cutoff state to execute the cutoff process.

According to such a battery device, a battery management program, and a method for managing the battery device, the current cutoff unit is cut off by the cutoff process when the high load does not operate. In other words, when the current cutoff unit is in the cutoff state, the high load does not operate, so that it is possible to prevent a current exceeding the maximum allowable current of the voltage drop element from flowing to the voltage drop element. As a result, it is possible to prevent the voltage drop element from being damaged by the large current without using a voltage drop element having a large maximum allowable current.

The battery devices and vehicles disclosed herein may have the following configurations:
As one embodiment of the battery device disclosed in the present specification, a voltage detection unit for detecting the voltage across the current cutoff unit is provided, and the control unit switches the current cutoff unit to an energized state to detect the voltage. The current cutoff unit is based on the first voltage detection process, the second voltage detection process of executing the cutoff process to detect the voltage, the voltage of the first voltage detection process, and the voltage of the second voltage detection process. It may be configured to execute a failure diagnosis process for diagnosing whether or not is a failure.

According to the battery device having such a configuration, when the current cutoff unit is cut off in the second voltage detection process of the failure diagnosis, the parallel circuit prevents the load and the secondary battery from being cut off. It is possible to determine whether or not the current cutoff unit is in a failed state based on the voltage of the first voltage detection process and the voltage of the second voltage detection process.
That is, the voltage drop element is damaged by a large current while preventing the voltage drop element for facilitating failure diagnosis from becoming large due to a voltage difference between the energized state and the cutoff state of the current cutoff portion. You can prevent that.

As one embodiment of the battery device disclosed in the present specification, the failure diagnosis process may be performed in a shorter time than the start time for starting the high load.
According to such a configuration, the failure diagnosis process is performed in about several hundred milliseconds, which is shorter than the starting time for starting a high load such as a starter motor, which causes a sense of discomfort when starting a high load. Failure diagnosis processing can be performed without any problem.
As one embodiment of the battery device disclosed in the present specification, a charging device for charging the secondary battery is connected to the secondary battery via the current cutoff portion, and the voltage drop element is the second. It may be configured as a diode that allows current to flow from the next battery to the load.

According to such a configuration, since the voltage drop value becomes constant when the current cutoff portion is in the cutoff state, the state of the current cutoff portion can be easily determined as compared with the case where the voltage drop is variable. Further, since only the discharge from the secondary battery can be allowed to the load while the current cutoff unit is in the cutoff state, it is possible to prevent the secondary battery from being charged and becoming an overcharged state.

As one embodiment of the battery device disclosed in the present specification, the parallel circuit may be configured to have an auxiliary current cutoff unit connected in series with the voltage drop element and switching between an energized state and a cutoff state.
According to such a configuration, the discharge can be cut off by the auxiliary current blocking unit before the secondary battery becomes over-discharged, so that it is possible to prevent the secondary battery from reaching the over-discharged state.

As one embodiment of the battery apparatus disclosed herein, the control unit makes the load system, which controls the operation of the load before executing the cutoff process, during the cutoff process. It may be configured to give a prohibition instruction to prevent the load from operating.
According to such a configuration, by issuing a prohibition instruction from the battery device to the load system, it is possible to prohibit the operation of a high load and perform the cutoff process, so that the maximum allowable current of the voltage drop element can be determined. It is possible to prevent the excess current from flowing to the voltage drop element, and it is possible to prevent the voltage drop element from being damaged.

As one embodiment of the battery device disclosed in the present specification, the control unit is instructed to allow the current cutoff unit to be output after the load system that controls the operation of the load prohibits the operation of the high load. The cutoff process may be performed by inputting the data.
According to such a configuration, the control unit executes the cutoff process according to the cutoff permission instruction output when the load system prohibits the operation of a high load, so that the current exceeding the maximum allowable current of the voltage drop element is the voltage drop element. It is possible to prevent the voltage drop element from being damaged.

As one embodiment of the vehicle disclosed in the present specification, the control unit receives the cutoff permission instruction to be output after the load system prohibits the high load operation by the prohibition instruction. It may be configured to execute the process.
According to such a configuration, the load system prohibits the operation of a high load by the prohibition instruction from the control unit, and the control unit shuts off the current interruption device based on the interruption permission instruction output thereafter. It is possible to prevent the descent element from being damaged by a large current.

<Embodiment 1>
The first embodiment in which the technique disclosed in the present specification is applied to a vehicle 10 such as an automobile will be described with reference to FIGS. 1 to 8.

As shown in FIG. 1, the vehicle 10 of the present embodiment is connected to a vehicle load (an example of "load") 12 such as a starter motor for starting an engine and electrical components installed in the engine room 11 and a vehicle load 12. The battery device 20, the vehicle load 12, a vehicle generator (an example of a "charging device") 14 such as an alternator connected to the battery device 20, and a vehicle-side electronic control device (an example of a "charging device") that controls the operation of the vehicle load 12. Hereinafter, it is configured to include (referred to as "vehicle ECU") 13. The vehicle-side electronic control device is an example of a load system.

The vehicle load 12 operates by being supplied with electric power from the battery device 20 and the vehicle generator 14, and receives electric power from the battery device 20 when the amount of electric power supplied from the vehicle generator 14 is small. Works with.
The vehicle generator 14 rotates as the engine of the vehicle 10 is driven to generate electric power, and supplies electric power to the vehicle load 12 and the battery device 20.

The vehicle ECU 13 is communicably connected to the vehicle load 12, the vehicle generator 14, the battery device 20, and the like by the communication line W, and the engine and the vehicle load 12 are connected based on the state of the vehicle 10, the state of the battery device 20, and the like. Control the operation. In FIG. 1, the communication line W is partially omitted in order to make the figure easier to understand. Further, as the communication method between the vehicle ECU 13 and the battery device 20, for example, LIN communication or the like can be used.

As shown in FIG. 2, the battery device 20 has a block-shaped battery case 21, and in the battery case 21, a plurality of secondary batteries connected in series as shown in FIGS. 3 and 4. A battery 30, a battery management device (hereinafter referred to as "BMU") 50 for managing these secondary batteries 30, a current sensor 40 for detecting the current flowing through the secondary battery 30, a current cutoff circuit 80, and the like are accommodated. There is.

In FIG. 3, in order to make the configuration of the battery case 21 easy to understand, the current sensor 40 and the current cutoff circuit 80 are not shown, and the internal structure is simplified. Further, in the following description, when referring to FIGS. 2 and 3, the vertical direction of the battery case 21 when the battery case 21 is placed horizontally without inclination with respect to the installation surface is the Y direction, and the battery case 21 The direction along the long side direction will be the X direction, and the depth direction of the battery case 21 will be the Z direction.

The battery case 21 is made of synthetic resin, and the upper surface wall 21A of the battery case 21 has a substantially rectangular shape in a plan view and has a height difference in the Y direction as shown in FIGS. 2 and 3. ing. A pair of terminal portions 22 to which harness terminals (not shown) are connected are provided at both ends of the lower portion of the upper surface wall 21A in the X direction in a state of being embedded in the upper surface wall 21A. The pair of terminal portions 22 are made of, for example, a metal such as a lead alloy, and one of the pair of terminal portions 22 is a positive electrode side terminal portion 22P and the other is a negative electrode side terminal portion 22N.

Further, as shown in FIG. 3, the battery case 21 is mounted on a box-shaped case body 23 that opens upward, a positioning member 24 that positions a plurality of secondary batteries 30, and an upper portion of the case body 23. It is configured to include a lid 25 and an upper lid 26 attached to the upper part of the inner lid 25.
As shown in FIG. 3, a plurality of cell chambers 23A in which a plurality of secondary batteries 30 are individually housed are provided in the case main body 23 side by side in the X direction.

As shown in FIG. 3, the positioning member 24 has a plurality of bus bars 27 arranged on the upper surface, and the positioning member 24 is arranged on the upper part of the plurality of secondary batteries 30 arranged in the case main body 23. , A plurality of secondary batteries 30 are positioned and connected in series by a plurality of bus bars 27.
As shown in FIG. 3, the inner lid 25 is capable of accommodating the BMU 50 inside, and the inner lid 25 is attached to the case body 23 so that the secondary battery 30 and the BMU 50 are connected to each other. It has become.

The secondary battery 30 is a lithium ion battery using, for example, a negative electrode active material of a graphite-based material and a positive electrode active material of an iron phosphate such as LiFePO4, and a plurality of secondary batteries 30 connected in series are As shown in FIG. 4, the current sensor 40 and the current cutoff circuit 80 are connected in series to the secondary battery 30 so that the current sensor 40 is on the negative electrode side and the current cutoff circuit 80 is on the positive electrode side. Then, in the plurality of secondary batteries 30 connected in series, the current sensor 40 is connected to the negative electrode side terminal portion 22N, and the current cutoff circuit 80 is connected to the positive electrode side terminal portion 22P, respectively, so that the current sensor 40 and the current are connected. It is connected to a pair of terminal portions 22 via a cutoff circuit 80.

As shown in FIG. 4, the BMU 50 includes a control unit 60 and a voltage detection circuit (an example of a “voltage detection unit”) 70.
The voltage detection circuit 70 is connected to both ends of the current cutoff circuit 80 and both ends of each secondary battery 30 via a voltage detection line. Then, in response to an instruction from the control unit 60, the voltage detection circuit 70 responds to the voltage CV1 across the current cutoff circuit 80, the voltage of each secondary battery 30, and the total voltage of the plurality of secondary batteries 30 connected in series. Measure V.

The control unit 60 includes a central processing unit (hereinafter referred to as “CPU”) 61, a memory 63, a communication unit 65, and a current detection unit 67, and the current detection unit 67 passes through the current sensor 40. The current flowing through the secondary battery 30 is measured.

In the memory 63, various programs for controlling the operation of the BMU 50 and data necessary for executing various programs, for example, individual and total over-discharge voltage thresholds of the secondary battery 30, individual and total excess of the secondary battery 30 The charging voltage threshold and the like are stored. Further, the memory 63 stores the voltage and current measured by the control unit 60 and the voltage detection circuit 70.
The communication unit 65 is communicably connected to the vehicle ECU 13, transmits a command generated by the vehicle ECU 13 to the control unit 60 from the vehicle ECU 13 side, and sends a command generated by the CPU 61 of the control unit 60 to the control unit 60. It is transmitted from the side to the vehicle ECU 13.

The CPU 61 controls each part of the battery device 20 based on the voltage and current measured by the voltage detection circuit 70 and the current detection unit 67, and various programs and data read from the memory 63, and protects the secondary battery 30. ..

As shown in FIG. 5, the current cutoff circuit 80 includes a current cutoff device 81 and a parallel circuit 83 connected in parallel with the current cutoff device 81.
The current cutoff device 81 is, for example, a contact relay (mechanical switch), so that one end is connected to the secondary battery 30 and the other end is connected to the positive electrode side terminal 24P. It is arranged between the secondary battery 30 and the positive electrode side terminal portion 24P. Further, the current cutoff device 81 operates in response to a command from the CPU 61 of the BMU 50 to switch between the secondary battery 30 and the positive electrode side terminal portion 24P between the energized state and the cutoff state. In the present embodiment, the current cutoff device 81 is configured by a contact relay, but may be configured by, for example, a semiconductor switch such as an FET.

The parallel circuit 83 has a diode (an example of a “voltage drop element”) 82, and the diode 82 has a vehicle load 12 from the secondary battery 30 side to the positive electrode side terminal portion 24P side, that is, from the secondary battery 30 side. It is arranged so that the current direction toward the side is the forward direction. When the current cutoff device 81 is cut off, a forward current flows through the diode 82, and a voltage drop of the forward voltage Vf occurs between both ends of the diode 82. The forward voltage Vf is a substantially constant value and is stored in the memory 63 in advance.

On the other hand, in order to protect the secondary battery 30, the CPU 61 is a current cutoff device 81 based on the voltage and current measured by the voltage detection circuit 70 and the current detection unit 67 and various programs stored in the memory 63. The battery protection process for switching the current, the failure diagnosis process for the current cutoff device 81, and the like are executed.

The battery protection process will be described below with reference to FIG.
In the battery protection process, the CPU 61 detects the individual voltage V1 of each secondary battery 30 and the total voltage V2 of the plurality of secondary batteries 30 connected in series in the voltage detection circuit 70 (S11), and the individual voltage V1 and The total voltage V2 is compared with the individual overcharge voltage threshold and the total overcharge voltage threshold stored in the memory 63 stored in the memory 63 (S12).
The individual overcharge voltage threshold is a value slightly smaller than the voltage value when one of the secondary batteries 30 is in the overcharge state, and the total overcharge voltage threshold is a plurality of connected in series. The value is slightly smaller than the voltage value when the secondary battery 30 is in the overcharged state.

When any one of the individual voltages V1 of each secondary battery 30 is determined to be equal to or higher than the individual overcharge voltage threshold value, or the total voltage V2 is determined to be equal to or higher than the total overcharge voltage threshold value (S12: YES), the CPU 61 is the secondary battery. Assuming that 30 may reach an overcharged state, a cutoff switching command for switching to the cutoff state is transmitted to the current cutoff device 81. Then, the current cutoff device 81 is switched to the cutoff state (S13), and the current between the secondary battery 30 and the vehicle generator 14 is cut off to prevent the secondary battery 30 from reaching the overcharged state. Then, the battery protection process is completed.

On the other hand, when the CPU 61 determines that all the individual voltages V1 are smaller than the individual overcharge voltage threshold and the total voltage V2 is smaller than the total overcharge voltage threshold (S12: NO), each individual voltage V1 And the total voltage V2 is compared with the individual over-discharge voltage threshold and the total over-discharge voltage threshold stored in the memory 63 (S14). The individual over-discharge voltage threshold is a value slightly larger than the voltage value when one of the secondary batteries 30 is in the over-discharged state, and the total over-discharge voltage threshold is a plurality of secondary batteries connected in series. The value is slightly larger than the voltage value when the battery 30 is in the over-discharged state.

The CPU 61 determines that any of the individual voltages V1 of each secondary battery 30 is smaller than the individual overcharge voltage threshold, and the total voltage V2 is smaller than the total overcharge voltage threshold. When it is determined that any of the individual voltages V1 of each secondary battery 30 is equal to or less than the individual overdischarge voltage threshold, or the total voltage V2 is determined to be equal to or less than the total overdischarge voltage threshold (S12: NO and S14: YES). Assuming that the secondary battery 30 may reach an over-discharged state, a cutoff switching command is transmitted to the current cutoff device 81. Then, the current cutoff device 81 is switched to the cutoff state (S15), and the current between the secondary battery 30 and the vehicle generator 14 is cut off to prevent the secondary battery 30 from reaching the overdischarged state. Then, the battery protection process is completed.

On the other hand, when the CPU 61 determines that all the individual voltages V1 are smaller than the individual overcharge voltage threshold and the total voltage V2 is smaller than the total overcharge voltage threshold, all the individual voltages V1 When it is determined that is larger than the individual over-discharge voltage threshold and the total voltage V is larger than the total over-discharge voltage threshold (S12: NO and S14: NO), the battery protection process is terminated.
Then, by repeating this battery protection process constantly or periodically, it is possible to prevent the secondary battery 30 from being in an overcharged state or an overdischarged state.

Next, the failure diagnosis process of the current cutoff device 81 will be described with reference to FIG. 7.
The failure diagnosis of the current cutoff device 81 is executed, for example, when a predetermined time has elapsed from the time of the previous execution of the failure diagnosis process and the discharge current measured by the current detection unit 67 becomes less than the predetermined value. .. In other words, the failure diagnosis process of the current cutoff device 81 is executed when the vehicle 10 does not move for a predetermined time and is in a parked state.
The failure of the current cutoff device 81 is an open failure in which the current cutoff device 81 remains in the cutoff state even if the CPU 61 gives an energization switching instruction due to a failure of the magnetic coil for driving the current cutoff device 81 or the like. For example, there is a close failure in which the current cutoff device 81 remains energized even if the CPU 61 gives a cutoff switching instruction due to welding of the contacts of the current cutoff device 81 or the like.

In the failure diagnosis of the current cutoff device 81, the CPU 61 determines whether or not the current cutoff device 81 has failed by switching the current cutoff device 81 between the energized state and the cutoff state. Then, when it is determined that the failure is occurring, it is diagnosed whether the failure is an open failure or a closed failure.

By the way, for example, while the current cutoff device 81 is in the cutoff state in the failure diagnosis process, the current or dark current supplied to the low load of the vehicle load 12 that is lower than the maximum allowable current of the diode 82 is passed through the diode 82. The current flows from the secondary battery 30 side to the vehicle load 12 side. However, if the vehicle 10 is started while the current cutoff device 81 is in the cutoff state, a large current flows from the secondary battery 30 with respect to the vehicle load 12 such as the starter motor. Here, if the large current exceeds the maximum allowable current of the diode 82, that is, the high load 12A of the vehicle load 12 that is operated by the power supply exceeding the maximum allowable current of the diode 82 is operated. When a large current flows from the battery 30, the diode 82 is damaged. However, when a diode having a large maximum allowable current is used, the mounting space of the diode increases as the diode becomes larger, and the manufacturing cost increases.

Therefore, in the failure diagnosis in the present embodiment, the CPU 61 gives a prohibition instruction to the vehicle ECU 13 not to operate the high load 12A before executing the cutoff process for switching the current cutoff device 81 from the energized state to the cutoff state. Do.

Specifically, when the failure diagnosis is started, the CPU 61 measures the voltage CV1 across the current cutoff circuit 80 by the voltage detection circuit 70 (S22).
Here, since the current cutoff device 81 is normally in the energized state, the voltage CV1 across the ends is measured as the closed voltage CV1 when the current cutoff device 81 is in the energized state. The process of S21 and S22 corresponds to the "first voltage detection process".

Next, the CPU 61 measures the open voltage CV2 when the current cutoff device 81 of the current cutoff circuit 80 is in the cutoff state by the voltage detection circuit 70, and calculates the voltage difference ΔCV between the closed voltage CV1 and the open voltage CV2. However, before issuing the cutoff switching instruction to the current cutoff device 81, the CPU 61 gives a prohibition instruction to the vehicle ECU 13 via the communication unit 65 so as not to operate the high load 12A (S23). Here, the prohibition instruction means, for example, transmitting a pulse signal (Wake up signal) having a specific width defined by the LIN communication standard.

Then, the CPU 61 starts monitoring whether the cutoff permission notification is output from the vehicle ECU 13 (S24). Then, when it is detected that the cutoff permission notification is output from the vehicle ECU 13 (S24: YES), the CPU 61 transmits a cutoff switching command to the current cutoff device 81 (S25), and the current cutoff of the current cutoff circuit 80 is cut off. The open voltage CV2 when the device 81 is in the cutoff state is measured by the voltage detection circuit 70 (S26). The process of S25 and S26 corresponds to the "second voltage detection process".

Then, the CPU 61 calculates the absolute value (| CV1-CV2 |) of the difference between the closed voltage CV1 and the open voltage CV2 as the voltage difference ΔCV, and compares the voltage difference ΔCV with the forward voltage Vf stored in the memory 63. (S27).

As a result of comparison, when the voltage difference ΔCV is almost the same as the forward voltage Vf (S27: YES), the current cutoff device 81 changes from the energized state to the cutoff state, a forward current flows through the diode 82, and both ends of the diode 82. It is determined that a voltage drop of the forward voltage Vf has occurred between them. That is, the current cutoff device 81 is diagnosed as having no failure (S28), and the failure diagnosis process is terminated.

On the other hand, when the voltage difference ΔCV is almost zero (S27: NO), the voltage CV1 across the current cutoff circuit 80 and the forward voltage Vf are further compared (S29).
When the voltage CV1 across the current cutoff circuit 80 and the forward voltage Vf are substantially the same (S29: YES), a forward current flows through the diode 82, causing a voltage drop of the forward voltage Vf between both ends of the diode 82. Is determined, and the current cutoff device 81 is diagnosed as an open failure (S29-1).
On the other hand, when the voltage CV1 across the current cutoff circuit 80 is almost zero (when the voltage CV1 across the ends and the forward voltage Vf are not almost the same) (S29: NO), it is determined that current is flowing through the current cutoff device 81. , A closed failure is diagnosed (S29-2).

Next, the prohibition process of the vehicle ECU 13 according to the prohibition instruction output from the CPU 61 will be described with reference to FIG.
The vehicle ECU 13 monitors whether a prohibition instruction is output from the control unit 60 in the BMU 50 of the battery device 20 (S31), and when the prohibition instruction is input (S31: YES), the high load 12A of the vehicle load 12 It is determined whether it is possible to prohibit the operation of (S32).

If the operation of the high load 12A cannot be prohibited (S32: NO), the high load 12A is monitored until it can be determined that there is no problem in prohibiting the operation of the high load 12A.
On the other hand, when it is determined that there is no problem in prohibiting the operation of the high load 12A (S32: YES), the vehicle ECU 13 prohibits the operation of the high load 12A for a predetermined period (S33). Of the vehicle loads 12, the vehicle load 12 that is not the high load 12A can be operated, and the control of the vehicle 10 and the like can be maintained.
Then, when the operation of the high load 12A is prohibited, the vehicle ECU 13 outputs a cutoff permission notification to the control unit 60 of the battery device 20 (S34), and ends the prohibition process.

As described above, according to the present embodiment, the closed voltage CV1 and the current cutoff device 81 when the diode 82 is connected in parallel with the current cutoff device 81 and the current cutoff device 81 is energized in the failure diagnosis process are used. Since the voltage difference ΔCV having the same magnitude as the forward voltage Vf is generated between the open voltage CV2 and the open voltage CV2 in the cutoff state, the failure diagnosis of the current cutoff device 81 can be easily performed.

Then, in the failure diagnosis process, before issuing a cutoff switching command to the current cutoff device 81, a prohibition instruction is given to the vehicle ECU 13 to prohibit the operation of the high load 12A exceeding the maximum allowable current of the diode 82. , Because the vehicle ECU 13 outputs a cutoff permission notification (the vehicle ECU 13 prohibits the operation of the high load 12A for a predetermined period of time), and issues a cutoff switching command to the current cutoff device 81. , It is possible to prevent a current exceeding the maximum allowable current from flowing through the diode 82.

That is, according to the present embodiment, the diode 82 is large while preventing the diode 82 from becoming large in size, which facilitates failure diagnosis by causing a voltage difference between the energized state and the cutoff state in the current cutoff device 81. It can be prevented from being damaged by the electric current.

Further, according to the present embodiment, since the diode 82 having a substantially constant voltage drop is connected in parallel with the current cutoff device 81, only the voltage CV1 across the current cutoff circuit 80 and the forward voltage Vf are compared. Therefore, it is possible to easily diagnose whether the failure of the current cutoff device 81 is an open failure or a closed failure.

Further, according to the present embodiment, the diode 82 is adopted as the voltage drop element connected in parallel with the current cutoff device 81, and the current direction flowing through the diode 82 is in the forward direction from the secondary battery 30 toward the vehicle load 12. Therefore, for example, the secondary battery 30 is overcharged by the vehicle generator 14 while preventing the vehicle load 12 from being unable to supply electric power from the secondary battery 30 during the control of the vehicle 10. Can be prevented.
Further, according to the present embodiment, the failure diagnosis process can be performed in about several hundred milliseconds, which is shorter than the starting time for starting the vehicle load 12 such as the starter motor, so that a feeling of strangeness is felt when the vehicle 10 is started. Can be carried out without causing

<Embodiment 2>
Next, the second embodiment will be described with reference to FIGS. 9 to 11.
The current cutoff circuit 180 of the second embodiment is a modification of the configuration of the parallel circuit 83 of the current cutoff circuit 80 of the first embodiment, and the configuration, operation, and effect common to the first embodiment are duplicated. The description will be omitted. Further, the same reference numerals are used for the same configurations as in the first embodiment.

The parallel circuit 183 in the current cutoff circuit 180 of the second embodiment has an auxiliary current cutoff device 184 connected in series with the diode 82 in addition to the diode 82.
The auxiliary current cutoff device 184 is, for example, a contact relay (mechanical switch) in which one end is connected to the secondary battery 30 and the other end is connected to the diode 82. It is arranged between the battery 30 and the diode 82. Further, the auxiliary current cutoff device 184 operates in response to a command from the CPU 61 of the BMU 50 to switch between the secondary battery 30 and the diode 82 in the energized state and the cutoff state.

In the present embodiment, the auxiliary current cutoff device 184 is configured by the contact relay, but for example, as shown in FIG. 10, the auxiliary current cutoff device 284 may be configured by the FET switch. In this case, for example, the FET switch is, for example, a P-channel MOSFET, and the FET switch is connected to the secondary battery 30 at the source, the BMU 50 at the gate, and the diode 82 at the drain.

The battery protection treatment according to the present embodiment will be described below with reference to FIG.
In the battery protection process of the present embodiment, the same process as the battery protection process of the first embodiment is performed, but an additional process is performed after that.
Specifically, in the battery protection process, the CPU 61 determines that any of the individual voltages V1 of each secondary battery 30 is smaller than the individual overcharge voltage threshold, and the total voltage V2 is smaller than the total overcharge voltage threshold or less. When it is determined that any of the individual voltages V1 of each secondary battery 30 is equal to or less than the individual overdischarge voltage threshold, or the total voltage V2 is determined to be equal to or less than the total overdischarge voltage threshold (S12: NO). In addition, S14: YES), assuming that the secondary battery 30 may reach an over-discharged state, a cutoff switching command is transmitted to the current cutoff device 81 to switch the current cutoff device 81 to the cutoff state (S15).

Then, after the current cutoff device 81 is switched to the cutoff state, the CPU 61 further sets any of the individual voltages V1 of each secondary battery 30 to or less than the individual overdischarge voltage final threshold value, or the total voltage V2 is the total overdischarge voltage. It is determined whether it is equal to or less than the final threshold value (S116).
Here, the individual over-discharge voltage final threshold is a value slightly larger than the voltage value when one of the secondary batteries 30 is in the over-discharged state, and is a value slightly smaller than the individual over-discharge voltage threshold. The total over-discharge voltage final threshold is a value slightly larger than the voltage value when a plurality of secondary batteries 30 connected in series are in an over-discharged state, and is slightly smaller than the total over-discharge voltage threshold. The value.

Then, when it is determined that any of the individual voltages V1 of each secondary battery 30 is equal to or less than the individual over-discharge voltage final threshold, or the total voltage V2 is determined to be equal to or less than the total over-discharge voltage final threshold (S116: YES), parallel. A cutoff switching instruction is transmitted to the auxiliary current cutoff device 184 in the circuit 183 to switch to the cutoff state (S117), and the current between the secondary battery 30 and the vehicle generator 14 is completely cut off. As a result, it is possible to prevent the secondary battery 30 from reaching an over-discharged state due to a dark current or the like of the vehicle load 12 (electrical components) mounted on the vehicle 10.

In the failure diagnosis process of the current cutoff device 81 in the present embodiment, the diagnosis is made by the same operation as in the first embodiment. Further, at this time, it is assumed that the auxiliary current cutoff device 184 is normal. This is because the auxiliary current cutoff device 184 is not used to supply electric power to the high load 12A, and the probability of failure is extremely low as compared with the current cutoff device 81.

As described above, according to the present embodiment, even if the current cutoff device 81 is in the cutoff state and can be discharged from the parallel circuit 183 through the diode 82, the secondary battery 30 may reach the overdischarged state due to a dark current or the like. If there is, the auxiliary current cutoff device 184 can surely prevent the secondary battery 30 from being over-discharged.

<Embodiment 3>
Next, the third embodiment will be described with reference to FIGS. 12 and 13.
In the failure diagnosis process of the third embodiment, the BMU 50 executes the failure diagnosis process when the CPU 61 in the control unit 60 of the BMU 50 receives an instruction from the vehicle ECU 13, and the configuration and operation common to those of the first embodiment. , And the effects are duplicated, so the description thereof will be omitted. Further, the same reference numerals are used for the same configurations as in the first embodiment.

That is, the vehicle ECU 13 determines the necessity of the failure diagnosis, and if it determines that it is necessary, the failure diagnosis is executed in the BMU 50 after executing the prohibition process.
The prohibition process when the vehicle ECU 13 determines that the failure diagnosis is necessary will be described below with reference to FIG.

The vehicle ECU 13 confirms whether the operation of the high load 12A among the vehicle loads 12 can be prohibited (S132), and if the operation of the high load 12A cannot be prohibited (S132: NO), the operation of the high load 12A is prohibited. Monitor the high load 12A until it can be confirmed that there is no problem.

When it is confirmed that there is no problem even if the operation of the high load 12A is prohibited (S132: YES), the vehicle ECU 13 prohibits the high load 12A from operating for a predetermined period (S133). Of the vehicle loads 12, the vehicle load 12 that is not the high load 12A can be operated, and the control of the vehicle 10 and the like can be maintained.

Then, when the operation of the high load 12A is prohibited, a cutoff permission notification is output to the control unit 60 of the battery device 20 (S134), and the prohibition process is terminated.

Next, the failure diagnosis process in the BMU 50 will be described with reference to FIG.
In the failure diagnosis process of the third embodiment, as shown in FIG. 13, the CPU 61 monitors whether the cutoff permission notice is output from the vehicle ECU 13 (S221), and the cutoff permission notice is output from the vehicle ECU 13. Upon detection, the CPU 61 transmits an energization switching command for switching to the energization state to the current cutoff device 81 (S222), and measures the voltage CV1 across the current cutoff circuit 80 by the voltage detection circuit 70 (S223). The process of S222 and S223 corresponds to the "first voltage detection process".

Next, the CPU 61 transmits a cutoff switching command to the current cutoff device 81 (S224), and the voltage detection circuit 70 measures the open voltage CV2 when the current cutoff device 81 is in the cutoff state (S225). The process of S224 and S225 corresponds to the "second voltage detection process".
Then, the CPU 61 calculates the absolute value (| CV1-CV2 |) of the difference between the closed voltage CV1 and the open voltage CV2 as the voltage difference ΔCV, and compares the voltage difference ΔCV with the forward voltage Vf stored in the memory 63. (S226).

As a result of comparison, when the voltage difference ΔCV is almost the same as the forward voltage Vf (S226: YES), the current cutoff device 81 changes from the energized state to the cutoff state, a forward current flows through the diode 82, and both ends of the diode 82. It is determined that a voltage drop of the forward voltage Vf has occurred between them. That is, the current cutoff device 81 is diagnosed as having no failure (S227), and ends the failure diagnosis process.

On the other hand, when the voltage difference ΔCV is almost zero (S226: NO), the voltage CV1 across the current cutoff circuit 80 and the forward voltage Vf are further compared (S228).
When the voltage CV1 across the current cutoff circuit 80 and the forward voltage Vf are substantially the same (S228: YES), a forward current flows through the diode 82, causing a voltage drop of the forward voltage Vf between both ends of the diode 82. Is determined, and the current cutoff device 81 is diagnosed as an open failure (S228-1).

On the other hand, when the voltage CV1 across the current cutoff circuit 80 is almost zero (S228: NO), it is determined that current is flowing through the current cutoff device 81 of the current cutoff circuit 80, and a closed failure is diagnosed (S228-2). ).
That is, according to the present embodiment, after the vehicle ECU 13 determines that the failure diagnosis is necessary and the prohibition process is executed, the failure diagnosis is executed in the BMU 50, so that a current exceeding the maximum allowable current flows through the diode 82. You can prevent that.

As a result, the diode 82 is damaged by a large current while preventing the diode 82 from becoming large in size, which facilitates failure diagnosis by causing a voltage difference between the energized state and the cutoff state in the current cutoff device 81. Can be prevented.

<Other embodiments>
The techniques disclosed herein are not limited to the embodiments described above and in the drawings, and include, for example, various aspects such as:
(1) In the above embodiment, the battery management device 50 is composed of one CPU 61. However, the battery management device is not limited to this, and may be a configuration including a plurality of CPUs, a hard circuit such as an ASIC (Application Specific Integrated Circuit), a microcomputer, an FPGA, an MPU, or a configuration in which they are combined. ..

(2) In the above embodiment, the diode 82 is used as the voltage drop element. However, the present invention is not limited to this, and a resistance element may be used as the voltage drop element.
(3) In the above embodiment, the communication method between the vehicle ECU 13 and the battery device 20 is configured as LIN communication. However, the communication method between the vehicle ECU and the battery device is not limited to this, and the communication method may be CAN communication or may be configured by another communication method.

(4) In the above embodiment, the prohibition instruction is output before the current cutoff device 81 is put into the cutoff state in the failure diagnosis process. However, the present invention is not limited to this, and a prohibition instruction may be output before the current cutoff device is turned off, regardless of the failure diagnosis.
(5) In the above embodiment, the CPU 61 outputs a prohibition instruction to the vehicle ECU 13, and the vehicle ECU 13 outputs a cutoff permission notification, so that the CPU 61 transmits a cutoff switching command to the current cutoff device 81. However, the present invention is not limited to this, and the CPU may transmit a cutoff switching command to the current cutoff device when the CPU outputs a prohibition instruction to the vehicle ECU.

(6) In the above embodiment, it is assumed that the auxiliary current cutoff device 184 is normal, and the failure diagnosis process of the current cutoff device 81 is executed. However, the present invention is not limited to this, and failure may be diagnosed not only in the current breaking device but also in the auxiliary current breaking device.
(7) In the above embodiment, the voltage detection circuit 70 is configured to measure the voltage CV1 across the current cutoff circuit 80. However, not limited to this, the voltage of the current cutoff device and the positive terminal side (terminal voltage of the battery device) and the voltage of the current cutoff device and the secondary battery side (the total value of the voltages of each secondary battery or connected in series). The voltage across the current cutoff circuit may be indirectly obtained by taking the difference from the total voltage of the plurality of secondary batteries.

10: Vehicle 12: Vehicle load (an example of "load")
12A: High load 13: Vehicle-side electronic control device (an example of "load system")
14: Vehicle generator (an example of "charging device")
20: Battery device 30: Secondary battery 60: Control unit 70: Voltage detection circuit (an example of "voltage detection unit")
81: Current cutoff device 82: Diode (an example of "voltage drop element")
83,183: Parallel circuit 184,284: Auxiliary current breaker

Claims (4)

A vehicle that includes a battery device, a load, and a load system that controls the operation of the load.
The battery device
A current cutoff device that cuts off the current to the load and a voltage drop element connected in parallel to the current cutoff device are included.
The battery device does not operate a load that operates by receiving a power supply exceeding the maximum allowable current of the voltage drop element to the load system before executing a cutoff process for switching the current cutoff device to the cutoff state. Give a prohibition instruction to
After receiving the prohibition instruction, the load system prohibits the operation of a load that operates by receiving a power supply exceeding the maximum allowable current of the voltage drop element.
A vehicle that gives a cutoff permission instruction to the current cutoff device to the battery device when a load that operates by receiving a power supply exceeding the maximum allowable current of the voltage drop element does not operate. The vehicle according to claim 1 .
When the load system receives the prohibition instruction, the load system determines whether the operation of the load can be prohibited.
A vehicle that prohibits the operation of the load and outputs the cutoff permission instruction to the battery device when the operation of the load can be prohibited. The vehicle according to claim 1 .
When the load system receives the prohibition instruction, the load system determines whether the operation of the load can be prohibited.
If the operation of the load cannot be prohibited, the vehicle that prohibits the operation of the load and outputs the cutoff permission instruction to the battery device after the operation can be prohibited. The vehicle according to any one of claims 1 to 3 .
The load system is a vehicle that gives a cutoff permission instruction to the battery device while the battery device is parked in which only a dark current is discharged.

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