JP2020022366A - vehicle - Google Patents

Abstract

To prevent a voltage drop element from being damaged by a heavy current, without using a voltage drop element of which the maximum allowable current is high.SOLUTION: A battery device 20 comprises: a secondary battery 30 for supplying power to a vehicle load 12 that is mounted on a vehicle 10; a current cut-off device 81 which switches the secondary battery 30 and the vehicle load 12 between an electrified state and a cut-off state; a parallel circuit 83 connected to the current cut-off device 81 in parallel and including a diode 82 through which a current flows, thereby generating a voltage drop; and a control section 60. While a high load 12A that works by receiving power supply exceeding the maximum allowable current of the diode 82 is not operated, a CPU 61 of the control section 60 executes cut-off processing for switching the current cut-off device 81 into the cut-off state, thereby detecting a voltage across the current cut-off device 81.SELECTED DRAWING: Figure 8

Description

  The technology disclosed in this specification relates to a battery device, a vehicle, a battery management program, and a battery device management method.

  For example, as a battery unit having a switch unit mounted on a vehicle, a battery unit disclosed in Japanese Patent Application Laid-Open No. 5-2055781 (Patent Document 1 below) is known. This battery unit opens the switch means when the load on the vehicle increases and the voltage drop of the battery continues for a predetermined time, and disconnects the load on the vehicle from the battery to prevent overdischarge of the battery.

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

JP-A-5-205781

  By the way, in the case of such a battery unit, if the switch means is faulty, it becomes impossible to prevent an abnormal state such as overdischarge or overcharge of the battery, and it is necessary to detect the fault of the switch means. . Therefore, it has been studied to perform a fault diagnosis of the current interrupting device by connecting the voltage dropping element in parallel with the switch means and detecting a voltage drop caused by the voltage dropping element while interrupting the current in the current interrupting 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 interrupted 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 increases, and the manufacturing cost increases.

  The present 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 in this specification includes a secondary battery that supplies power to a load, a current interrupting unit that switches between the secondary battery and the load between an energized state and an interrupted state, A parallel circuit having a voltage drop element that causes a voltage drop when a current flows, and a control unit, wherein the control unit operates at a high load operated by a power supply exceeding a maximum allowable current of the voltage drop element. When does not operate, the interruption process for switching the current interruption unit to the interruption state is executed.

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

FIG. 1 is a diagram illustrating a vehicle according to a first embodiment. Perspective view of the battery device Exploded perspective view of the battery device Block diagram of battery device Diagram showing current cutoff circuit Flowchart of battery protection processing Flow chart of failure diagnosis processing Flowchart diagram of prohibition processing FIG. 4 is a diagram illustrating a current cutoff circuit according to a second embodiment. The figure which shows the modification of an auxiliary electric current interruption device Flowchart of battery protection processing Flow chart of a prohibition process according to the third embodiment Flow chart of failure diagnosis processing

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

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

Further, the vehicle disclosed in the present embodiment has a configuration including the battery device, the load, and a load system that controls operation of the load.
Further, the vehicle disclosed in the present embodiment is a vehicle including the battery device, the load, and the load system, wherein the load system receives the high load by receiving the prohibition instruction. Is prohibited from operating.

  Further, a battery management program disclosed in the present embodiment includes: a secondary battery that supplies power to a load; a current interrupting unit that switches between the secondary battery and the load between an energized state and an interrupted state; And a parallel circuit having a voltage drop element that generates a voltage drop when a current flows, the control section of the battery device having a voltage higher than the maximum allowable current of the voltage drop element. When the load does not operate, a configuration is adopted in which a cutoff process for switching the current cutoff unit to a cutoff state is executed.

  Further, the method for managing a battery device disclosed in the present embodiment includes a secondary battery that supplies power to a load, a current interrupting device that switches between the secondary battery and the load to an energized state and an interrupted state, A parallel circuit having a voltage drop element that is connected in parallel to the current interrupting device and causes a voltage drop when a current flows, comprising: a power supply that exceeds a maximum allowable current of the voltage drop element. When the high load that operates in response to the current interruption does not operate, the interruption processing for switching the current interruption device to the interruption state is performed.

  According to the battery device, the battery management program, and the management method of the battery device, when the high load does not operate, the current interrupting unit is turned off by the interrupting process. In other words, when the current cutoff unit is in the cutoff state, the high load does not operate, so that a current exceeding the maximum allowable current of the voltage drop element can be prevented from flowing through 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 device and the vehicle disclosed in the present specification may have the following configurations.
As one embodiment of the battery device disclosed in the present specification, the battery device includes a voltage detection unit that detects a voltage between both ends of the current interruption unit, and the control unit switches the current interruption unit to an energized state to detect a voltage. A first voltage detection process, a second voltage detection process for executing the cutoff process to detect a voltage, and the current cutoff unit based on a voltage of the first voltage detection process and a voltage of the second voltage detection process. And a failure diagnosis process for diagnosing whether or not a failure has occurred.

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. In addition, it can be determined whether or not the current interrupting unit is in a failure 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 the large current while preventing the voltage drop element for causing a voltage difference between the energized state and the cutoff state of the current cutoff unit to facilitate failure diagnosis from being enlarged. Can be prevented.

As one embodiment of the battery device disclosed in the present specification, the failure diagnosis process may be configured to be performed in a shorter time than a start time for starting the high load.
According to such a configuration, for example, the failure diagnosis process is performed in a few hundred milliseconds shorter than a start time for starting a high load such as a starter motor, so that a sense of incongruity is generated when starting a high load. Without this, the failure diagnosis processing can be performed.
As one embodiment of the battery device disclosed in the present specification, a charging device that charges the secondary battery is connected to the secondary battery via the current cutoff unit, and the voltage drop element includes the secondary battery. It may be configured to be a diode that allows current to flow from the secondary battery to the load.

  According to such a configuration, the voltage drop value becomes constant when the current cutoff unit is in the cutoff state, so that the state of the current cutoff unit can be easily determined as compared with the case where the voltage drop is variable. In addition, since only discharging from the secondary battery to the load can be permitted while the current interrupting unit is in the interrupted state, it is possible to prevent the secondary battery from being overcharged by being charged.

As one embodiment of the battery device disclosed in the present specification, the parallel circuit may be configured to include an auxiliary current cutoff unit that is connected in series with the voltage drop element and switches between an energized state and a cutoff state.
According to such a configuration, the discharge can be cut off by the auxiliary current cutoff section before the secondary battery is overdischarged, so that the secondary battery can be prevented from reaching an overdischarged state.

As one embodiment of the battery device disclosed in the present specification, the control unit may be configured to control the load system that controls the operation of the load before performing the cutoff process, during the cutoff process. A configuration may be employed in which a prohibition instruction for not operating the load is issued.
According to such a configuration, by performing a prohibition instruction from the battery device to the load system, it is possible to prohibit the operation of the high load and perform the cutoff process, so that the maximum allowable current of the voltage drop element is reduced. Excess current can be prevented from flowing to the voltage drop element, and the voltage drop element can be prevented from being damaged.

As one embodiment of the battery device disclosed in the present specification, the control unit may output a cutoff permission instruction of the current cutoff unit that is output after a load system that performs operation control of the load prohibits the high load operation. The cutoff process may be performed by being input.
According to such a configuration, since the control unit performs the cutoff process according to the cutoff permission instruction output by prohibiting the operation of the high load by the load system, a current exceeding the maximum allowable current of the voltage drop element is output. Can be prevented, and the voltage drop element can be prevented from being damaged.

As one embodiment of the vehicle disclosed in the present specification, the control unit may be configured to perform the cutoff by inputting a cutoff permission instruction output after the load system prohibits the high-load operation by the prohibition instruction. It may be configured to execute the processing.
According to such a configuration, the load system prohibits the high-load operation by the prohibition instruction from the control unit, and the control unit sets the current cut-off device to the cut-off state based on the cut-off permission instruction output thereafter. The falling element can be prevented from being damaged by a large current.

<First embodiment>
Embodiment 1 in which the technology disclosed in this 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 according to the present embodiment is connected to a vehicle load (an example of a “load”) 12 such as a starter motor for starting an engine and electric components installed in an engine room 11 and a vehicle load 12. Battery device 20, a vehicle load 12 and 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 ( Hereinafter, the vehicle ECU 13 is provided. The vehicle-side electronic control device is an example of a load system.

The vehicle load 12 operates by being supplied with power from the battery device 20 and the vehicle generator 14, and receives power from the battery device 20 when the amount of power supplied from the vehicle generator 14 is small. Works with
The vehicle generator 14 generates power by rotating with the driving of the engine of the vehicle 10, and supplies 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 via a communication line W, and based on the state of the vehicle 10, the state of the battery device 20, and the like. Perform operation control. Note that, in FIG. 1, the communication line W is partially omitted for easy understanding. Further, as a communication method between the vehicle ECU 13 and the battery device 20, for example, LIN communication or the like can be used.

  The battery device 20 has a block-shaped battery case 21 as shown in FIG. 2, and a plurality of secondary batteries connected in series as shown in FIGS. The battery 30, a battery management device (hereinafter, referred to as “BMU”) 50 for managing the secondary batteries 30, a current sensor 40 for detecting a current flowing through the secondary battery 30, a current cutoff circuit 80, and the like are housed therein. I have.

  In FIG. 3, the current sensor 40 and the current cutoff circuit 80 are not shown and the internal structure is simplified in order to make the configuration of the battery case 21 easy to understand. 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 defined as the Y direction, The direction along the long side direction will be described as an X direction, and the depth direction of the battery case 21 will be described as a Z direction.

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

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

As shown in FIG. 3, the positioning member 24 has a plurality of bus bars 27 disposed on an upper surface, and the positioning member 24 is disposed above a plurality of secondary batteries 30 disposed 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 cover 25 is capable of storing the BMU 50 therein, and the inner cover 25 is attached to the case body 23 so that the secondary battery 30 and the BMU 50 are connected. Has become.

  The secondary battery 30 is, for example, a lithium ion battery using a negative electrode active material of a graphite material and an iron phosphate-based positive electrode active material 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 such that the current sensor 40 is on the negative side and the current cutoff circuit 80 is on the positive side with respect to the secondary battery 30. The plurality of rechargeable batteries 30 connected in series include the current sensor 40 connected to the negative terminal 22N, and the current cutoff circuit 80 connected to the positive terminal 22P. 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 determines 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 a “CPU”) 61, a memory 63, a communication unit 65, and a current detection unit 67. Thus, the current flowing through the secondary battery 30 is measured.

The memory 63 includes various programs for controlling the operation of the BMU 50 and data necessary for executing the various programs, for example, individual and total overdischarge voltage thresholds of the secondary battery 30, individual and total overvoltage of the secondary battery 30. A 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. The communication unit 65 transmits a command generated by the vehicle ECU 13 to the control unit 60 from the vehicle ECU 13 and transmits a command generated by the CPU 61 of the control unit 60 to the control unit 60. Side to the vehicle ECU 13.

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

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

  The parallel circuit 83 includes a diode (an example of a “voltage drop element”) 82. The diode 82 is connected from the secondary battery 30 side to the positive terminal portion 24 </ b> P, that is, from the secondary battery 30 side to the vehicle load 12. The current direction toward the side is arranged in a direction in which the forward direction is set. 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 determines the current interruption 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. , A failure diagnosis process of the current interrupting device 81, and the like.

Hereinafter, the battery protection process will be described with reference to FIG.
In the battery protection process, the CPU 61 causes the voltage detection circuit 70 to detect the individual voltage V1 of each secondary battery 30 and the total voltage V2 of the plurality of secondary batteries 30 connected in series (S11), 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).
Note that the individual overcharge voltage threshold is a value slightly smaller than a voltage value when one of the secondary batteries 30 is in the overcharge state, and the total overcharge voltage threshold is a plurality of serially connected multiple overcharge voltage thresholds. This is a value slightly smaller than the voltage value when the secondary battery 30 is in the overcharged state.

  If the CPU 61 determines that any one of the individual voltages V1 of the respective secondary batteries 30 is equal to or higher than the individual overcharge voltage threshold, or determines that the total voltage V2 is equal to or higher than the total overcharge voltage threshold (S12: YES), It is determined that there is a possibility that the battery 30 will be in an overcharged state. Then, the current interrupting device 81 is switched to the interrupted state (S13), and the current between the secondary battery 30 and the vehicle generator 14 is interrupted to suppress the secondary battery 30 from reaching an overcharged state. Then, the battery protection process ends.

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

  The CPU 61 determines that any one of the individual voltages V1 of the respective secondary batteries 30 is smaller than the individual overcharge voltage threshold, and determines that the total voltage V2 is smaller than the total overcharge voltage threshold. When any of the individual voltages V1 of the respective secondary batteries 30 is determined to be equal to or less than the individual overdischarge voltage threshold, or when the total voltage V2 is determined to be equal to or less than the total overdischarge voltage threshold (S12: NO and S14: YES), A cutoff switching command is transmitted to the current cutoff device 81 on the assumption that the secondary battery 30 may be in an overdischarged state. 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 suppress the secondary battery 30 from reaching an overdischarged state. Then, the battery protection process ends.

On the other hand, the CPU 61 determines that all the individual voltages V1 are smaller than the individual overcharge voltage threshold, and determines that the total voltage V2 is smaller than the total overcharge voltage threshold. Is determined to be greater than the individual overdischarge voltage threshold, and if the total voltage V is determined to be greater than the total overdischarge voltage threshold (S12: NO and S14: NO), the battery protection process ends.
By repeating this battery protection process constantly or periodically, the secondary battery 30 is prevented from being in an overcharged state or an overdischarged state.

Next, a failure diagnosis process of the current interruption device 81 will be described with reference to FIG.
The failure diagnosis of the current interrupting device 81 is performed, for example, when a predetermined time has elapsed since the previous failure diagnosis processing was performed and the discharge current measured by the current detection unit 67 is less than a predetermined value. . In other words, the failure diagnosis process of the current interrupting device 81 is executed when the vehicle 10 has not moved and has been parked for a predetermined time.
Note that the failure of the current interrupting device 81 is an open failure in which the current interrupting device 81 remains in the interrupted state even when the CPU 61 instructs the energization switching due to a malfunction of the magnetic coil for driving the current interrupting device 81 or the like. For example, there is a close failure in which the current interrupting device 81 remains energized even when the CPU 61 issues an interrupt switching instruction due to, for example, welding of a contact point of the current interrupting device 81.

  In the failure diagnosis of the current interrupting device 81, the CPU 61 determines whether the current interrupting device 81 has a failure by switching the current interrupting device 81 between an energized state and an interrupted state. Then, when it is determined that a failure has occurred, it is determined 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 processing, a current or a dark current supplied to a low load of the vehicle load 12 that is lower than the maximum allowable current of the diode 82 passes through the diode 82. It flows from the secondary battery 30 side to the vehicle load 12 side. However, when 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 to the vehicle load 12 such as a starter motor. Here, if the large current exceeds the maximum allowable current of the diode 82, that is, if the high load 12A that operates by the power supply exceeding the maximum allowable current of the diode 82 of the vehicle load 12, the secondary 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 with the increase in the size of the diode, and the manufacturing cost increases.

  Therefore, in the failure diagnosis according to the present embodiment, the CPU 61 issues a prohibition instruction to the vehicle ECU 13 to prevent the high load 12A from operating before executing the interruption process for switching the current interruption device 81 from the energized state to the interrupted 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 interrupting device 81 is normally in the energized state, the voltage CV1 between both ends is measured as the closed voltage CV1 when the current interrupting device 81 is in the energized state. Note that the processing in S21 and S22 corresponds to “first voltage detection processing”.

  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 giving the interruption switching instruction to the current interruption device 81, the CPU 61 gives an instruction to prohibit the vehicle ECU 13 from operating the high load 12A via the communication unit 65 (S23). Here, the prohibition instruction is, 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 or not a cutoff permission notification is output from the vehicle ECU 13 (S24). Then, upon detecting that the cutoff permission notification has been output from the vehicle ECU 13 (S24: YES), the CPU 61 transmits a cutoff switching command to the current cutoff device 81 (S25), and cuts off the current of the current cutoff circuit 80. The open voltage CV2 when the device 81 is in the cutoff state is measured by the voltage detection circuit 70 (S26). Note that the processing of S25 and S26 corresponds to “second voltage detection processing”.

  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 the comparison, when the voltage difference ΔCV is substantially the same as the forward voltage Vf (S27: YES), the current interrupting device 81 changes from the energized state to the interrupted state, a forward current flows through the diode 82, and both ends of the diode 82 It is determined that the forward voltage Vf has dropped during this time. That is, the current interrupting device 81 is diagnosed that there is no failure (S28), and the failure diagnosis processing ends.

On the other hand, when the voltage difference ΔCV is substantially zero (S27: NO), the voltage CV1 across the current cutoff circuit 80 is further compared with the forward voltage Vf (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, so that the voltage drop of the forward voltage Vf across the diode 82 occurs. Is determined to have occurred, and the current interrupting device 81 is diagnosed as an open failure (S29-1).
On the other hand, when the voltage CV1 between both ends of the current cutoff circuit 80 is substantially zero (when the voltage CV1 between both ends is not substantially the same as the forward voltage Vf) (S29: NO), it is determined that the current is flowing through the current cutoff device 81. Is diagnosed as a close failure (S29-2).

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

If the operation of the high load 12A cannot be prohibited (S32: NO), the high load 12A is monitored until it is determined that there is no problem even if the operation of the high load 12A is prohibited.
On the other hand, when it is determined that there is no problem even if the operation of the high load 12A is prohibited (S32: YES), the vehicle ECU 13 prohibits the operation of the high load 12A for a predetermined period (S33). The vehicle load 12 that is not the high load 12A among the vehicle loads 12 is operable, and the control of the vehicle 10 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 processing.

  As described above, according to the present embodiment, the diode 82 is connected in parallel to the current interrupting device 81, and in the failure diagnosis processing, the closed voltage CV1 when the current interrupting device 81 is in the energized state and the current interrupting device 81 Since the voltage difference ΔCV having the same magnitude as the forward voltage Vf is generated between the open circuit voltage CV2 and the open voltage CV2 in the case of 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, the vehicle ECU 13 is instructed to prohibit the operation of the high load 12A exceeding the maximum allowable current of the diode 82. Since the vehicle ECU 13 outputs a cut-off permission notification (the operation of the high load 12A is prohibited for a predetermined period by the vehicle ECU 13), the cut-off switching command is issued to the current cut-off device 81. , A current exceeding the maximum allowable current can be prevented from flowing through the diode 82.

  That is, according to the present embodiment, the diode 82, which facilitates fault diagnosis by generating a voltage difference between the energized state and the interrupted state in the current interrupting device 81, is prevented from becoming large, while the diode 82 is enlarged. Damage due to electric current can be prevented.

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

Further, according to the present embodiment, the diode 82 is employed as the voltage drop element connected in parallel with the current interrupting device 81, and the current flowing through the diode 82 is in the forward direction from the secondary battery 30 toward the vehicle load 12. For example, the secondary battery 30 is overcharged by the vehicle generator 14 while preventing the vehicle load 12 from being unable to supply power from the secondary battery 30 during control of the vehicle 10. Can be prevented.
Further, according to the present embodiment, for example, the failure diagnosis process can be performed in about several hundred milliseconds shorter than the start time for starting the vehicle load 12 such as a starter motor. Can be implemented without causing

<Embodiment 2>
Next, a second embodiment will be described with reference to FIGS.
The current cutoff circuit 180 according to the second embodiment is obtained by changing the configuration of the parallel circuit 83 of the current cutoff circuit 80 according to the first embodiment, and has the same configuration, operation, and effect as those of the first embodiment. The description is omitted. Further, the same reference numerals are used for the same configuration as the first embodiment.

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

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

Hereinafter, the battery protection process according to the present embodiment will be described 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 thereafter.
Specifically, in the battery protection process, the CPU 61 determines that any one of the individual voltages V1 of the respective secondary batteries 30 is smaller than the individual overcharge voltage threshold, and the total voltage V2 is smaller than the total overcharge voltage threshold or less. And it is determined that any one of the individual voltages V1 of the secondary batteries 30 is equal to or less than the individual overdischarge voltage threshold, or that the total voltage V2 is equal to or less than the total overdischarge voltage threshold (S12: NO) And, S14: YES), it is determined that there is a possibility that the secondary battery 30 may be in an overdischarged state, and 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 switching the current cutoff device 81 to the cutoff state, the CPU 61 further sets any one of the individual voltages V1 of the respective secondary batteries 30 to be equal to or less than the individual overdischarge voltage final threshold, or the total voltage V2 becomes the total overdischarge voltage It is determined whether it is equal to or less than the final threshold (S116).
Here, the individual overdischarge voltage final threshold value is a value slightly larger than the voltage value when one of the secondary batteries 30 is in the overdischarge state, and is a value slightly smaller than the individual overdischarge voltage threshold value. The total overdischarge voltage final threshold is a value slightly larger than the voltage value when the plurality of rechargeable batteries 30 connected in series are in the overdischarge state, and slightly smaller than the total overdischarge voltage threshold. Value.

  If any one of the individual voltages V1 of the respective secondary batteries 30 is determined to be equal to or lower than the individual overdischarge voltage final threshold, or if the total voltage V2 is determined to be equal to or lower than the total overdischarge voltage final threshold (S116: YES), the parallel operation is performed. 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. Thus, it is possible to prevent the secondary battery 30 from being over-discharged due to dark current or the like of the vehicle load 12 (electrical component) mounted on the vehicle 10.

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

  As described above, according to the present embodiment, even when 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 be overdischarged due to dark current or the like. In such a case, the auxiliary current interrupting device 184 can reliably prevent the secondary battery 30 from being over-discharged.

<Embodiment 3>
Next, a third embodiment will be described with reference to FIGS.
The failure diagnosis processing according to the third embodiment is such that the BMU 50 executes the failure diagnosis processing when the CPU 61 of the control unit 60 of the BMU 50 receives an instruction from the vehicle ECU 13. , And the effect are duplicated, and the description thereof is omitted. Further, the same reference numerals are used for the same configuration as the first embodiment.

That is, the vehicle ECU 13 determines the necessity of the failure diagnosis, and if it determines that the failure diagnosis is necessary, the BMU 50 performs the failure diagnosis after performing the prohibition process.
Hereinafter, the prohibition processing when the vehicle ECU 13 determines that the failure diagnosis is necessary will be described with reference to FIG.

  The vehicle ECU 13 checks whether it is possible to prohibit the operation of the high load 12A among the vehicle loads 12 (S132), and if the operation of the high load 12A cannot be prohibited (S132: NO), prohibits the operation of the high load 12A. The high load 12A is monitored until it is confirmed that there is no problem.

  If 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). The vehicle load 12 that is not the high load 12A among the vehicle loads 12 is operable, and the control of the vehicle 10 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 ends.

Next, a 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 a cutoff permission notification is output from the vehicle ECU 13 (S221), and determines that the cutoff permission notification is output from the vehicle ECU 13. Upon detection, the CPU 61 transmits an energization switching command to switch to the energized state to the current interrupting device 81 (S222), and measures the voltage CV1 across the current interrupting circuit 80 using the voltage detection circuit 70 (S223). Note that the processing of S222 and S223 corresponds to “first voltage detection processing”.

Next, the CPU 61 transmits a cutoff switching command to the current cutoff device 81 (S224), and measures the open voltage CV2 when the current cutoff device 81 is in the cutoff state by the voltage detection circuit 70 (S225). Note that the processing in S224 and S225 corresponds to “second voltage detection processing”.
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 the comparison, when the voltage difference ΔCV is substantially the same as the forward voltage Vf (S226: YES), the current interrupting device 81 changes from the energized state to the interrupted state, and a forward current flows through the diode 82, and both ends of the diode 82 It is determined that the forward voltage Vf has dropped during this time. That is, the current interrupting device 81 is diagnosed as having not failed (S227), and the failure diagnosis processing ends.

On the other hand, when the voltage difference ΔCV is almost zero (S226: NO), the voltage CV1 across the current cutoff circuit 80 is further compared with the forward voltage Vf (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, so that the voltage drop of the forward voltage Vf across the diode 82 occurs. Is determined to have occurred, and the current interruption 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 substantially zero (S228: NO), it is determined that the current is flowing through the current cutoff device 81 of the current cutoff circuit 80, and a close 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 executes the prohibition processing, the failure diagnosis is performed in the BMU 50. Therefore, a current exceeding the maximum allowable current flows through the diode 82. Can be prevented.

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

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described above and illustrated in the drawings, and includes, for example, the following various aspects.
(1) In the above embodiment, the battery management device 50 is constituted by one CPU 61. However, the present invention is not limited to this, and the battery management device may be a configuration including a plurality of CPUs, a hardware circuit such as an ASIC (Application Specific Integrated Circuit), a microcomputer, an FPGA, an MPU, or a configuration in which these are combined. .

(2) In the above embodiment, the diode 82 is used as the voltage drop element. However, the invention is not limited thereto, and a resistance element may be used as the voltage drop element.
(3) In the above embodiment, the communication system 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 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 interrupting device 81 is turned off in the failure diagnosis process. However, the present invention is not limited to this, and a configuration may be adopted in which a prohibition instruction is output before the current interrupting device is turned off regardless of the failure diagnosis.
(5) In the above embodiment, the prohibition instruction is output from the CPU 61 to the vehicle ECU 13, and the cutoff permission notification is output from the vehicle ECU 13, 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 a prohibition instruction is output from the CPU to the vehicle ECU.

(6) In the above embodiment, the configuration is such that the failure diagnosis processing of the current interrupting device 81 is executed on the assumption that the auxiliary current interrupting device 184 is normal. However, the present invention is not limited to this, and failures of not only the current interrupt device but also the auxiliary current interrupt device may be diagnosed.
(7) In the above embodiment, the voltage detection circuit 70 measures the voltage CV1 across the current cutoff circuit 80. However, the present invention is not limited to this, and the voltage between the current interrupting device and the positive terminal portion (terminal voltage of the battery device) and the voltage between the current interrupting device and the secondary battery (the total value of the voltages of the respective secondary batteries or connected in series) Alternatively, the voltage between the two ends of the current cutoff circuit may be obtained indirectly by taking the difference with 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 a “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 interrupting device 82: Diode (an example of "voltage drop element")
83, 183: parallel circuits 184, 284: auxiliary current cutoff device

Claims (12)

A secondary battery that supplies power to the load,
A current interrupting device that switches between the secondary battery and the load between an energized state and an interrupted state,
A parallel circuit having a voltage drop element that is connected in parallel to the current interrupting device and causes a voltage drop when a current flows;
And a control unit,
The battery device, wherein the control unit executes a cutoff process for switching the current cutoff device to a cutoff state when a high load that operates by receiving a power supply exceeding a maximum allowable current of the voltage drop element does not operate. A voltage detection unit that detects a voltage between both ends of the current interruption device,
The control unit includes:
A first voltage detection process of detecting a voltage by switching the current interrupting device to an energized state;
A second voltage detection process for detecting the voltage by executing the cutoff process;
2. The battery device according to claim 1, wherein a failure diagnosis process for diagnosing whether or not the current interrupting device has failed is performed based on the voltage of the first voltage detection process and the voltage of the second voltage detection process. 3.   3. The battery device according to claim 2, wherein the failure diagnosis process is performed in a shorter time than a start time for starting the high load. A charging device for charging the secondary battery is connected to the secondary battery via the current interrupt device,
4. The battery device according to claim 1, wherein the voltage drop element is a diode that flows a current from the secondary battery to the load. 5.   The battery device according to any one of claims 1 to 4, wherein the parallel circuit includes an auxiliary current cutoff device that is connected in series with the voltage drop element and switches between an energized state and a cutoff state.   The control unit issues a prohibition instruction to prevent the high load from operating during the cutoff process, to the load system that controls the operation of the load before executing the cutoff process. The battery device according to claim 5.   2. The controller according to claim 1, wherein the control unit performs the cutoff process by receiving a cutoff permission instruction of the current cutoff device that is output after the load system that controls the load operation prohibits the high load operation. A battery device according to claim 1. A battery device according to any one of claims 1 to 7,
Said load;
And a load system for controlling the operation of the load. A battery device according to claim 6,
Said load;
A vehicle having the load system;
The vehicle wherein the load system prohibits the high load from operating when the prohibition instruction is input.   The vehicle according to claim 9, wherein the control unit executes the cutoff process by receiving a cutoff permission instruction output after the load system prohibits the high-load operation according to the prohibition instruction. A secondary battery that supplies power to the load,
A current interrupting device that switches between the secondary battery and the load between an energized state and an interrupted state,
A controller connected in parallel to the current interrupting device, and a parallel circuit having a voltage drop element that causes a voltage drop when a current flows,
A battery management program for executing a cutoff process for switching the current cutoff device to a cutoff state when a high load that operates by receiving power supply exceeding a maximum allowable current of the voltage drop element does not operate. A secondary battery that supplies power to the load,
A current interrupting device that switches between the secondary battery and the load between an energized state and an interrupted state,
A parallel circuit having a voltage drop element that is connected in parallel to the current interrupting device and causes a voltage drop when a current flows, comprising:
A method of managing a battery device, comprising: executing a shutoff process for switching the current interrupting device to an interrupted state when a high load that operates by receiving power supply exceeding a maximum allowable current of the voltage drop element does not operate.

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