In-vehicle battery control device

Abstract

To provide an on-vehicle battery control device which can suppress an increase of a consumption current.SOLUTION: A battery ECU 10 controls a main battery 20 which includes a plurality of battery cells 201-20n including a plurality of even-numbered cells and a plurality of odd-numbered cells. The battery ECU 10 includes a plurality of equalization switches connected in series, and a plurality of monitoring ICs 21-2n which performs the voltage equalization of the plurality of battery cells. The battery ECU 10 further includes a microcomputer 1 whose power is supplied from an auxiliary battery 30 and which issues a control instruction to the plurality of monitoring ICs. As the plurality of equalization switches, the monitoring ICs include: a plurality of even-numbered switches provided corresponding to the even-numbered cells; and a plurality of odd-numbered switches provided corresponding to the odd-numbered cells. When an equalization instruction is given from the microcomputer, the monitoring ICs perform voltage equalization by switching, in a state that the microcomputer is not activated, an on-off control target between the even-numbered switches and the odd-numbered switches at each predetermined time based on a count value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle battery control device.

Background Art

[0002] Conventionally, as an example of an in-vehicle battery control device for controlling a battery pack, there is a battery pack monitoring system (Patent Document 1).

[0003] The battery pack monitoring system includes a voltage monitoring device that monitors the voltage of each battery cell in the battery pack, a discharge resistor element and an RC filter that are respectively connected between each battery cell and the voltage monitoring device, and a discharge switch that discharges the corresponding battery cell.

[0004] The voltage monitoring device is provided with three or more connection terminals corresponding to one battery cell. Two of these connection terminals are used to monitor the voltage of the battery cell via the output terminal of the RC filter. The remaining one or more connection terminals are used to form a discharge path for the battery cell when the discharge switch is turned on. In the battery pack monitoring system, in the discharge path, the discharge resistor element is arranged at a position where it does not discharge the charging charge of the capacitor constituting the RC filter. Further, the control device controls the on / off of the discharge switch to perform voltage equalization processing for each battery cell.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in recent vehicles, many ECUs are installed. For this reason, there is a demand for reducing the current consumption of the auxiliary battery that supplies power to each ECU.

[0007] Further, in Patent Document 1, when adjacent charge and discharge switches are both turned on, current corresponding to the adjacent RC filters flows, increasing the current value, which may lead to heat generation and malfunctions in a voltage monitoring device corresponding to the ECU. Therefore, in Patent Document 1, in order to perform voltage equalization, it is necessary to start the voltage monitoring device and switch between odd switches and even switches. Therefore, in Patent Document 1, there is a problem that the current consumption increases because the number of activations of the voltage monitoring device increases.

[0008] The present disclosure has been made in view of the above problems, and an object thereof is to provide an in-vehicle battery control device capable of suppressing an increase in current consumption.

Means for Solving the Problems

[0009] To achieve the above object, the present disclosure is an in-vehicle battery control device that controls a battery pack (20) including a plurality of battery cells (201 to 20n) including a plurality of even cells and a plurality of odd cells, including a plurality of monitoring ICs (21 to 2n) that are connected to the battery pack and supplied with power, and include a plurality of equalization switches (111 to 113 connected in series) for performing voltage equalization of the plurality of battery cells, capable of taking a state of not being activated that periodically repeats normal operation and standby operation, supplied with power from an auxiliary battery (30), and including a microcomputer (1) that gives control instructions to the plurality of monitoring ICs during normal operation. The monitoring IC includes, as the plurality of equalization switches, a plurality of even switches provided corresponding to even cells and a plurality of odd switches provided corresponding to odd cells, The microcontroller dynamically determines the switching time for switching the control target to be turned on between an even switch and an odd switch based on the variation in each cell voltage of the battery cells, and issues a control instruction including the switching time to the monitoring IC. The monitoring IC When an equalization instruction is given from the microcomputer, in a situation where the microcomputer is not activated, performs voltage equalization by switching the control target to be turned on between an even switch and an odd switch, and when the control target is turned on based on a count value measures the elapsed time, and when the elapsed time reaches the switching time, switches the control target to be turned on. .

[0010] In this way, This disclosure uses a count value because the control target for turning on and off when performing voltage equalization is switched between an even switch and an odd switch. And Even when the microcomputer is not activated, the monitoring IC can perform voltage equalization by switching the on / off control target between an even switch and an odd switch. Therefore, the present disclosure can reduce the number of times the microcomputer is activated for voltage equalization and can reduce the current consumption of the auxiliary battery.

[0011] Note that the claims and the reference numerals in parentheses described in this section indicate the correspondence with the specific means described in the embodiments described later as one aspect, and do not limit the technical scope of the present disclosure.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0013] With reference to FIGS. 1 to 6, modes for carrying out the present disclosure will be described. In the present embodiment, an example in which an in-vehicle battery control device is applied to a battery ECU (Electronic Control Unit) 10 is adopted.

[0014] First, with reference to FIGS. 1, 2, and 3, the configuration of the battery ECU 10 will be described. The battery ECU 10 controls a main battery 20 including a plurality of battery cells 201 to 20n including a plurality of even cells and a plurality of odd cells. The main battery 20 corresponds to a battery pack.

[0015] The battery ECU 10 includes a microcomputer 1 and first to nth monitoring ICs 21 to 2n. Further, the battery ECU 10 includes a printed circuit board 31 provided with a filter 4 and a discharge resistor 5. Also, the battery ECU 10 is electrically connected to the main battery 20 and the auxiliary battery 30. In this embodiment, as an example, the battery ECU 10 in which the microcomputer 1, the plurality of monitoring ICs 21 to 2n, and the printed circuit board 31 are configured as an integrated substrate is adopted. However, the present disclosure is not limited to this, and a satellite-type substrate battery ECU 10 can also be adopted. Note that n is a natural number of 2 or more.

[0016] The battery ECU 10 is configured to be mountable on vehicles such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles. The main battery 20 has a plurality of battery cells 201 to 20n such as lithium secondary batteries and nickel-metal hydride secondary batteries connected in series. The plurality of battery cells 201 to 20n are connected in series from the low-potential ground to the high-potential side.

[0017] As an example, the main battery 20 adopts a configuration in which a plurality of battery blocks are connected in series. Each battery block includes a plurality of battery cells connected in series. One battery block includes, for example, the first battery cell 201, the second battery cell 202, the third battery cell 203, the fourth battery cell 204, and the first battery cell 205.

[0018] Each battery block is electrically connected to different monitoring ICs 21 to 2n. For example, the battery block including the battery cells 201 to 205 is electrically connected to the first monitoring IC 21. And the battery block including the nth battery cell is electrically connected to the nth monitoring IC 2n.

[0019] The main battery 20 also includes a plurality of battery cells 201 to 20n including a plurality of even cells 20E (E: even) and a plurality of odd cells 20O (O: odd). Among the plurality of battery cells 201 to 20n, counting from the most upstream or the most downstream, the even-numbered battery cells are even cells 20E, and the odd-numbered battery cells are odd cells 20O.

[0020] For example, the battery cells 201 to 205 are electrically connected to the first monitoring IC 21. That is, the first monitoring IC 21 has connected thereto the first battery cell 201, the third battery cell 203, and the fifth battery cell 205 as odd cells, and the second battery cell 202 and the fourth battery cell 204 as even cells. Similarly, the nth battery cell is electrically connected to the nth monitoring IC 2n. The number of battery cells connected to each of the monitoring ICs 21 to 2n is not limited to this.

[0021] Note that the main battery 20 can also be referred to as a battery pack. Also, the battery cells 201 to 20n are similarly configured.

[0022] The auxiliary battery 30 has a terminal voltage lower than that of the main battery 20. The auxiliary battery 30 is electrically connected to a low-voltage circuit such as the microcomputer 1. Then, the auxiliary battery 30 supplies power to a low-voltage circuit such as the microcomputer 1.

[0023] The microcomputer 1 is supplied with power from the auxiliary battery 30 and issues control instructions to the plurality of monitoring ICs 21 to 2n. That is, the microcomputer 1 operates with power supplied from the auxiliary battery 30. The microcomputer 1 includes, for example, a CPU, a storage device, a communication circuit, and the like. The storage device includes a volatile memory such as an SRAM and a non-volatile memory such as a Flash Memory or an EEPROM.

[0024] In addition, the microcomputer 1 is electrically connected to each monitoring IC21~2n. The microcomputer 1 executes a program stored in a non-volatile memory by the CPU. By executing the program, the microcomputer 1 uses the volatile memory as a temporary storage unit and executes arithmetic processing using data stored in the storage device. As a result, the microcomputer 1 executes the processing operations described later. Note that data such as cell voltage values transmitted from the monitoring IC21~2n is stored in the storage device.

[0025] The microcomputer 1 is configured to be communicable with each monitoring IC21~2n. The microcomputer 1 issues a control instruction to each monitoring IC21~2n by transmitting a command to each monitoring IC21~2n. In addition, the microcomputer 1 receives data indicating the cell voltage values transmitted from each monitoring IC21~2n.

[0026] As the command, for example, a start command for instructing the start of voltage equalization, a stop command for instructing the stop of voltage equalization, and a detection command for instructing the detection (measurement) of the cell voltage and the transmission of the detection result can be adopted. Furthermore, the command can also adopt a diagnosis command indicating the presence or absence of a circuit failure in each monitoring IC21~2. Note that the detection command may include an instruction for AD conversion. Also, the start command corresponds to an equalization instruction. Therefore, when the monitoring IC21~2n receives the start command, it is regarded that an equalization instruction has been given.

[0027] The plurality of monitoring IC21~2n are connected to the main battery 20 to be powered, and include a plurality of equalization switches 111~113 connected in series, and mainly perform voltage equalization of the plurality of battery cells 201~20n. Each of the plurality of monitoring IC21~2n has a similar configuration and performs similar processing operations. Therefore, in the following, the first monitoring IC21 will be described as a representative example.

[0028] As shown in FIG. 2, the first monitoring IC 21 includes a cell equalization circuit 110, an AD converter 120, a reference power supply 130, a logic circuit 140, a detection control unit 141, a communication control unit 142, an AD detection correction unit 143, an oscillator 150, a memory 160, a communication I / F 170, and the like.

[0029] The first monitoring IC 21 includes a plurality of sets of paired connection terminals. One battery cell is connected to one set of connection terminals of the first monitoring IC 21. The first monitoring IC 21 is configured to be able to detect the cell voltages of the respective battery cells 201 to 205.

[0030] As shown in FIGS. 2 and 3, the cell equalization circuit 110 includes a multiplexer (MUX) in addition to the equalization switches 111 to 113 for performing voltage equalization of the battery cells. In the present embodiment, the cell equalization circuit 110 including the multiplexer is used. However, in the present disclosure, the multiplexer and the cell equalization circuit 110 may be provided separately.

[0031] In the following, when it is not necessary to distinguish the respective equalization switches 111 to 113, they are simply referred to as equalization switches without giving reference numerals. Also, each of the equalization switches 111 to 113 can be said to be a discharge switch for discharging the corresponding battery cells 201 to 20n when turned on.

[0032] The cell equalization circuit 110 has a plurality of battery cells 201 to 205 electrically connected thereto via connection terminals. More specifically, the cell equalization circuit 110 has a plurality of battery cells 201 to 205 electrically connected thereto via a printed circuit board 31. The connection terminals can also be said to be cell voltage detection terminals.

[0033] As shown in FIG. 3, the printed circuit board 31 is provided with a filter 4, a discharge resistor 5, etc. The filter 4 and the discharge resistor 5 are provided between the corresponding equalization switch and the battery cell. The corresponding equalization switch and the battery cell are, for example, the first equalization switch 111 and the first battery cell 201, etc. The filter 4 includes a resistance element 41 and a capacitor 42. Therefore, it can be said that the first monitoring IC 21 is electrically connected to the battery cells 201 to 205 via the filter 4 and the discharge resistor 5.

[0034] As shown in FIG. 3, the printed circuit board 31 sets the connection destination of the capacitor 42 as the subsequent connection point a2 which is the subsequent stage of the discharge resistor 5, rather than the first connection point a1 which is the previous stage of the discharge resistor 5. Also, the monitoring IC 21 sets the connection destinations of the equalization switches 111 to 113 as the second connection point b2 which is the previous stage of the discharge resistor 5, rather than the intermediate connection b1 between the resistance element 41 and the capacitor 42.

[0035] In the present disclosure, by setting such connection points a2 and b2, the inter-terminal voltage of the cell voltage detection terminal returns at the moment when the equalization switch 111 is turned off, and the process can immediately proceed to the next process. That is, in the present disclosure, when performing the failure diagnosis of the monitoring IC 21 by turning the equalization switch 111 on and off, it is not necessary to wait for the return time determined by the RC time constant of the filter 4, and the processing time can be shortened.

[0036] The cell equalization circuit 110 is provided with an equalization switch corresponding to each of the plurality of battery cells 201 to 205. Also, the plurality of equalization switches include a plurality of even switches 11E provided corresponding to each even cell 20E and a plurality of odd switches 11O provided corresponding to each odd cell 20O.

[0037] Here, as an example, only the first equalization switch 111, the second equalization switch 111, and the third equalization switch 113 are illustrated. However, for example, the first monitoring IC 21 has the battery cells 201 to 205 electrically connected thereto. For this reason, the cell equalization circuit 110 of the first monitoring IC 21 is provided with five equalization switches corresponding to each of the battery cells 201 to 205. That is, each of the monitoring ICs 21 to 2n is provided with an equalization switch corresponding to each of the battery cells electrically connected thereto.

[0038] Note that the first equalization switch 111 is provided corresponding to the first battery cell 201. The second equalization switch 111 is provided corresponding to the second battery cell 202. The third equalization switch 113 is provided corresponding to the third battery cell 203.

[0039] In a vehicle equipped with the main battery 20, in order to maximize the utilization of regenerative energy, it is necessary to keep the cell voltages equal. For this purpose, the first monitoring IC 21 is provided with a cell equalization circuit 110 as a function of equalizing the cell voltages. The first monitoring IC 21 periodically activates during a period when the ignition switch of the vehicle is off to perform equalization of the cell voltages. Equalization of the cell voltages corresponds to voltage equalization. Also, the battery ECU 10 preferably diagnoses the presence or absence of a circuit failure in the first monitoring IC 21 by turning the equalization switch on and off in order to perform voltage equalization.

[0040] The first monitoring IC 21 performs voltage equalization by turning the equalization switches 111 to 113 on and off. Each of the equalization switches 111 to 113 turns on and off in response to an instruction from the detection control unit 141 of the logic circuit 140.

[0041] The cell equalization circuit 110 can discharge the first battery cell 201, for example, by turning on the first equalization switch 111 in response to an instruction from the detection control unit 141. Therefore, the first monitoring IC 21 can equalize the cell voltages of the battery cells 201 to 205 by discharging the battery cell with a high cell voltage among the battery cells 201 to 205. As shown in FIG. 3, when the first equalization switch 111 is turned on, the battery ECU 10 has an equalization current flowing as indicated by the two-dot chain line, and the charge of the capacitor 42 of the filter 4 is discharged and a current flows as indicated by the one-dot chain line.

[0042] The multiplexer is composed of a plurality of switch circuits and selects one set out of a plurality of sets of connection terminals in response to an instruction from the detection control unit 141 of the logic circuit 140. By selecting one set, the multiplexer electrically connects one of the battery cells 201 to 205. And the multiplexer is provided with a voltage detection unit that detects the cell voltage of the connected battery cell. Also, the first monitoring IC 21 sequentially connects the battery cells 201 to 205 to the multiplexer and sequentially detects the cell voltages of the battery cells 201 to 205.

[0043] The AD converter 120 is connected to the reference power supply 130. The AD converter 120 performs AD conversion based on the reference voltage generated by the reference power supply 130. Also, the AD converter 120 performs AD conversion on each cell voltage detected by the multiplexer in response to an instruction from the detection control unit 141. And the AD converter 120 outputs the AD conversion result to the logic circuit 140. In FIG. 2, the AD converter 120 is abbreviated as ADC.

[0044] The logic circuit 140 includes, as functional blocks, a detection control unit 141, a communication control unit 142, an AD detection correction unit 143, etc. The logic circuit 140 is electrically connected to the oscillator 150, the memory 160, and the communication I / F 170.

[0045] The logic circuit 140 receives the clock signal generated by the oscillator 150. Note that the oscillator 150 can employ a ceramic oscillator, a crystal oscillator circuit including a crystal oscillator, etc. The logic circuit 140 refers to the data stored in the memory 160 and is configured to be able to rewrite the data in the memory 160. The communication I / F 170 is an interface circuit that communicates with the microcomputer 1 and other monitoring ICs 22 to 2n.

[0046] The detection control unit 141 outputs instructions to the cell equalization circuit 110 and the AD converter 120 according to the command transmitted from the microcomputer 1. For example, the detection control unit 141 outputs an instruction for detecting the cell voltage and an instruction for voltage equalization to the cell equalization circuit 110. Further, as an instruction for voltage equalization, the detection control unit 141 outputs an instruction to turn on the even switch 11E and an instruction to turn on the odd switch 11O at different timings.

[0047] The communication control unit 142 receives a command via the communication I / F 170 and transmits data indicating the cell voltage value, etc. via the communication I / F 170. The AD detection correction unit 143 acquires the cell voltage value AD-converted by the AD converter 120. The AD detection correction unit 143 corrects the acquired cell voltage value using the correction coefficient stored in the memory 160.

[0048] In particular, when an equalization instruction is given from the microcomputer 1, the first monitoring IC 21 switches the control target of on / off between the even switch 11E and the odd switch 11O at predetermined intervals based on the count value in a situation where the microcomputer 1 is not activated to perform voltage equalization. This is to prevent heat generation and malfunctions of the first monitoring IC 21 by preventing adjacent equalization switches from being turned on simultaneously and discharging the current of two filters at the same time. Note that the equalization switch to be turned on can also be referred to as the switch to be turned on target.

[0049] Here, the processing operations of the battery ECU 10 will be described with reference to FIGS. 4, 5, and 6. Note that the battery ECU operation in FIG. 6 mainly shows the operation of the microcomputer 1. Also, the vehicle IG in FIG. 6 is an abbreviation for the ignition switch of the vehicle.

[0050] First, the processing operation of the microcomputer 1 will be described with reference to FIG. 4. Here, as shown in FIG. 6, a situation where the battery ECU 10 starts (turns on) even when the vehicle IG is off and then the battery ECU 10 stops (turns off) is adopted as an example. The state in which the battery ECU 10 is started is the same as the state in which the microcomputer 1 is started. The state in which the battery ECU 10 is stopped is the same as the state in which the microcomputer 1 is not started. Also, the state in which the microcomputer 1 is not started indicates a state in which the microcomputer 1 periodically repeats normal operation and standby operation. Note that in FIG. 4, the battery ECU 10 is abbreviated as ECU.

[0051] The microcomputer 1, for example, starts at a certain period when the vehicle IG is off and performs the processing operations shown in the flowchart of FIG. 4. Also, the microcomputer 1 may start and perform the processing operations shown in the flowchart of FIG. 4 when a predetermined condition is satisfied while the vehicle IG is off.

[0052] In step S11, the ECU is started. The microcomputer 1 starts the battery ECU 10 by shifting from standby operation to normal operation. The microcomputer 1 shifts from standby operation to normal operation, for example, by the CPU outputting a power holding signal that holds the power supply from the auxiliary battery 30.

[0053] In step S12, cell voltage measurement is performed (voltage acquisition unit). The microcomputer 1 detects the cell voltages of the respective battery cells 201 to 20n by transmitting detection commands to the respective monitoring ICs 21 to 2n. Specifically, the microcomputer 1 transmits detection commands to the respective monitoring ICs 21 to 2n. The respective monitoring ICs 21 to 2n perform AD conversion of the cell voltage values of the respective battery cells 201 to 20n with the AD converter 120 in response to the detection commands. Then, the respective monitoring ICs 21 to 2n return the AD-converted cell voltage values to the microcomputer 1. Therefore, the microcomputer 1 acquires the cell voltage values of the respective battery cells 201 to 20n detected by the respective monitoring ICs 21 to 2n.

[0054] In step S13, cell voltage storage is performed (storage unit). The microcomputer 1 stores the cell voltage values transmitted from the respective monitoring ICs 21 to 2n in the storage device.

[0055] In step S14, it is determined whether the circuit is faulty (diagnosis unit). The microcomputer 1 determines whether the circuits of the respective monitoring ICs 21 to 2n are faulty. If the microcomputer 1 does not determine that the circuits of the respective monitoring ICs 21 to 2n are faulty, it proceeds to step S15, and if it determines that the circuits are faulty, it ends the processing operation of FIG. 4.

[0056] For example, the microcomputer 1 compares the current value, which is the current cell voltage value, with the previous value, which is the cell voltage value stored during the previous startup. The current cell voltage value is the cell voltage value stored in this step S13. On the other hand, the cell voltage value stored during the previous startup is the cell voltage value stored in the storage device in the previous step S13. Note that the microcomputer 1 may delete the previous value when the processing of step S14 ends.

[0057] Then, when the current value and the previous value do not satisfy a predetermined correspondence relationship, the microcomputer 1 can determine that the respective monitoring ICs 21 to 2n are faulty. That is, when the current value and the previous value satisfy a predetermined correspondence relationship, the microcomputer 1 determines that the respective monitoring ICs 21 to 2n are not faulty.

[0058] Also, when the microcomputer 1 can determine from the difference between the current value and the previous value that voltage equalization has been performed, it assumes that each monitoring IC 21 to 2n is not faulty and satisfies a predetermined correspondence. On the other hand, when the microcomputer 1 cannot determine from the difference between the current value and the previous value that voltage equalization has been performed, it assumes that each monitoring IC 21 to 2n is faulty and does not satisfy a predetermined correspondence.

[0059] Note that the microcomputer 1 transmits, for example, diagnostic commands to each of the monitoring ICs 21 to 2n. Each of the monitoring ICs 21 to 2n diagnoses the presence or absence of a circuit fault by turning on and off each of the equalization switches 111 to 11n in response to the diagnostic command. Then, each of the monitoring ICs 21 to 2n returns a response to the microcomputer 1.

[0060] In step S15, it is determined whether equalization is necessary. The microcomputer 1 refers to all the cell voltage values stored in the storage device in step S13. Then, the microcomputer 1 determines whether voltage equalization is necessary according to each cell voltage value. For example, when there are variations in the cell voltage values of the battery cells 201 to 205, the microcomputer 1 determines that voltage equalization is necessary. Also, when the cell voltage values of the battery cells 201 to 205 differ by exceeding a predetermined value, the microcomputer 1 may determine that voltage equalization is necessary.

[0061] In step S16, an equalization instruction is given. The microcomputer 1 gives an equalization instruction by transmitting a start command to each of the monitoring ICs 21 to 2n. It can be said that the microcomputer 1 turns on equalization by transmitting a start command.

[0062] Also, the microcomputer 1 transmits information indicating the switching time (x min) to each of the monitoring ICs 21 to 2n together with the start command. The switching time is the time when each of the monitoring ICs 21 to 2n switches the control targets of on and off between the even switches 11E and the odd switches 11O. That is, the switching time is the time when the control targets to be turned on and the control targets to be turned off are switched between the even switches 11E and the odd switches 11O.

[0063] For example, a case where the control target is such that the even switch 11E is turned on and the odd switch 11O is turned off will be described as an example. In this case, when the switching time has elapsed, each monitoring IC 21 to 2n switches to a control target for turning off the even switch 11E and switches to a control target for turning on the odd switch 11O.

[0064] In this way, the switching time can also be said to be a period in which one of the even switch 11E and the odd switch 11O is the control target to be turned on and the other is the control target to be turned off. And when this period has elapsed, the battery ECU 10 switches the control target to be turned on to the control target to be turned off and switches the control target to be turned off to the control target to be turned on.

[0065] In the present embodiment, a time in units of minutes is adopted as the switching time. However, the present disclosure is not limited to this, and a time in units of seconds can also be adopted as the switching time. Also, the switching time may be a predetermined static time or a time that is dynamically changed. When the microcomputer 1 determines the switching time dynamically, it may be determined based on the variation in each cell voltage value stored in the storage device. For example, the microcomputer 1 makes the switching time longer when the variation is larger than when the variation is smaller.

[0066] Note that the microcomputer 1 may determine whether voltage equalization is necessary for each battery block unit, or may determine whether voltage equalization is necessary for the entire main battery 20. In the former case, the microcomputer 1 transmits a start command to the monitoring IC to which the battery block determined to require voltage equalization is connected. In the latter case, the microcomputer 1 transmits a start command to all the monitoring ICs 21 to 2n.

[0067] In this way, the microcomputer 1 determines whether voltage equalization is necessary on the condition that the circuit is not faulty. Also, the microcomputer 1 performs voltage equalization on the condition that the circuit is not faulty and the cell voltages are not equal.

[0068] In step S17, the ECU is stopped. The microcomputer 1 stops the battery ECU 10 by shifting from the normal operation to the standby operation. For example, the microcomputer 1 shifts from the normal operation to the standby operation when the CPU stops outputting the power hold signal.

[0069] As described below, once the battery ECU 10 sends a start command, each monitoring IC21~2n automatically starts up and performs voltage equalization. Therefore, even when the microcomputer 1 determines that voltage equalization is necessary, it shifts to the standby operation when it sends the start command.

[0070] Next, the processing operations of each monitoring IC21~2n will be described with reference to FIG. 5. When each monitoring IC21~2n receives the start command, it performs the processing operations shown in the flowchart of FIG. 5. Note that the microcomputer 1 also sends the switching time together with the start command. Therefore, each monitoring IC21~2n will receive the switching time in addition to the start command. Note that each monitoring IC21~2n receives the start command and the switching time through the communication control unit 142 via the communication I / F 170, for example.

[0071] Also, when the microcomputer 1 sends the start command and the switching time as described above, it shifts to the standby operation. Therefore, each monitoring IC21~2n will perform the following steps S21~S26 in a situation where the microcomputer 1 is not started.

[0072] In step S21, the switching time is set. Each monitoring IC21~2n sets the received switching time as the time for switching between the even switch 11E and the odd switch 11O, which are the on / off control targets. For example, the detection control unit 141 stores the switching time received by the communication control unit 142 in the memory 160 for reference when determining the switching timing of the on / off control target. Therefore, in this embodiment, the switching time becomes the set time. Also, as shown in FIG. 6, the switching set time becomes x min.

[0073] In step S22, the odd-numbered equalization switches are turned on. As shown in FIG. 6, when each monitoring IC21 to 2n sets the switching time, it turns on the odd switch 11O, which is the odd-numbered equalization switch. That is, each monitoring IC21 to 2n is the control target for turning on the odd switch 11O and the control target for turning off the even switch 11E. At this time, for example, the detection control unit 141 outputs an instruction to turn on the odd switch 11O to the cell equalization circuit 110 as an instruction for voltage equalization.

[0074] The cell equalization circuit 110 turns on the odd switch 11O in response to the instruction to turn on the odd switch 11O. As a result, each monitoring IC21 to 2n can discharge a plurality of odd cells 20O. Also, at this time, the even switch 11E is in the off state.

[0075] Also, as shown in FIG. 6, when each monitoring IC21 to 2n turns on the odd switch 11O, it starts measuring the elapsed time. Each monitoring IC21 to 2n measures the elapsed time by counting the edges of the clock signal from the oscillator 150 in the logic circuit 140. However, the present disclosure is not limited to this, and the elapsed time may be measured by another method.

[0076] In step S23, it is determined whether it is the set time. Each monitoring IC21 to 2n determines whether it is the set time, that is, whether it is the switching time. For example, when the detection control unit 141 determines that the measured elapsed time has reached the switching time, it determines that it is the set time and proceeds to step S24. If the elapsed time has not reached the switching time, it does not determine that it is the set time and repeats step S23. In other words, when the logic circuit 140 determines that the count value obtained by counting the edges of the clock signal from the oscillator 150 has reached the switching time, it proceeds to step S23. If it determines that the count value has not reached the switching time, it repeats step S22.

[0077] In step S24, the even-numbered equalization switch is turned on. As shown in FIG. 6, when each monitoring IC21~2n sets the switching time, it turns on the even switch 11E, which is the even-numbered equalization switch. That is, each monitoring IC21~2n is the control target for turning on the even switch 11E and the control target for turning off the odd switch 11O. Also, it can be said that each monitoring IC21~2n switches the control target to be turned on from the odd switch 11O to the even switch 11E, and switches the control target to be turned off from the even switch 11E to the odd switch 11O. At this time, for example, the detection control unit 141 outputs an instruction to turn on the even switch 11E to the cell equalization circuit 110 as an instruction for voltage equalization.

[0078] The cell equalization circuit 110 turns on the even switch 11E in response to the instruction to turn on the even switch 11E. As a result, each monitoring IC21~2n can discharge a plurality of even cells 20E. Also, at this time, the odd switch 11O is in the off state. As shown in FIG. 6, each monitoring IC21~2n starts measuring the elapsed time when the even switch 11E is turned on.

[0079] In step S25, it is determined whether it is the set time in the same way as in step S23. Then, for example, when the detection control unit 141 determines that the measured elapsed time has reached the switching time, it determines that it is the set time and proceeds to step S26. If the elapsed time has not reached the switching time, it does not determine that it is the set time and repeats step S25.

[0080] In step S26, it is determined whether there is a stop instruction. Each monitoring IC21~2n determines whether there is a stop instruction based on the stop command from the microcomputer 1. For example, when the detection control unit 141 has not received the stop command, it determines that there is no stop instruction and returns to step S22. When it has received the stop command, it determines that there is a stop instruction and ends the flowchart of FIG. 5.

[0081] As described above, when each monitoring IC21 to 2n receives an equalization instruction from the microcomputer 1, based on the count value, it switches the on / off control target between the even switch 11E and the odd switch 11O at predetermined time intervals to perform voltage equalization. Also, each monitoring IC21 to 2n performs voltage equalization by switching the on / off control target between the even switch 11E and the odd switch 11O in a situation where the microcomputer 1 is not activated. That is, each monitoring IC21 to 2n can automatically switch the on / off control target and perform voltage equalization regardless of the activation state of the microcomputer 1.

[0082] As described above, even in a situation where the microcomputer 1 is not activated, the battery ECU 10 can perform voltage equalization by each monitoring IC21 to 2n switching the on / off control target between the even switch 11E and the odd switch 11O. Therefore, the battery ECU 10 can reduce the number of times the microcomputer 1 is activated for voltage equalization, and can reduce the current consumption of the auxiliary battery 30.

[0083] Also, in the present embodiment, the order in which voltage equalization is started is preset to start from the odd cells 20O. However, in the present disclosure, the order in which voltage equalization is started may be preset to start from the even cells 20E. That is, it is preferable that the order in which each monitoring IC21 to 2n starts voltage equalization is preset to be either the even cells 20E or the odd cells 20O. Thereby, the battery ECU 10 can prevent only one of the even cells 20E and the odd cells 20O from being equalized. Therefore, the battery ECU 10 can further suppress the variation in cell voltage among the plurality of battery cells 201 to 20n.

[0084] As described above, each monitoring IC21 to 2n uses, as the count value, the value obtained by counting the clock signal generated by the oscillator 150. Therefore, the interval (switching time) for each monitoring IC21 to 2n to switch the on / off control target between the even switch 11E and the odd switch 11O may be preset based on the accuracy of the oscillator 150. The switching time is preferably shortened as the accuracy of the oscillator 150 deteriorates.

[0085] Each monitoring IC21 to 2n cannot switch the on / off control target as per the switching time when the accuracy of the oscillator 150 is poor. That is, an error occurs between the instructed switching time and the time when the on / off control target is actually switched.

[0086] That is, each monitoring IC21 to 2n may turn on the on-target switch for a time longer than the time required to equalize the cell voltages. Also, each monitoring IC21 to 2n may turn off the on-target switch without turning it on for the time required to equalize the cell voltages. As a result, since the discharge times of the battery cells 201 to 20n vary in the battery ECU 10, even if voltage equalization is performed, there is a possibility that the cell voltages cannot be appropriately equalized.

[0087] However, the battery ECU 10 can reduce the error when switching the on / off control target once by shortening the switching time as the accuracy of the oscillator 150 deteriorates. Therefore, the battery ECU 10 can improve the accuracy of voltage equalization. That is, the battery ECU 10 can further suppress the variation in cell voltages among the plurality of battery cells 201 to 20n.

[0088] In this embodiment, an example of starting from the odd switch 11O is adopted. However, in the present disclosure, it may start from the even switch 11E.

[0089] In the present disclosure, the microcomputer 1 may determine the control target to be turned on first among the odd switch 11O and the even switch 11E and instruct each monitoring IC21 to 2n. In this case, the microcomputer 1 determines based on each cell voltage value acquired in step S12.

[0090] In the present disclosure, each monitoring IC21 to 2n may determine the control target to be turned on first among the odd switch 11O and the even switch 11E. Each monitoring IC21 to 2n determines based on the detected cell voltage values.

[0091] In the present disclosure, each monitoring IC 21 to 2n may determine step S26. Each monitoring IC 21 to 2n determines based on each detected cell voltage value.

[0092] Note that the present disclosure is not limited thereto. The battery ECU 10 may include at least one arithmetic processing unit (CPU), at least one memory device (MMR) as a storage medium for storing programs and data, and a monitoring IC. The battery ECU 10 is provided by a microcomputer including a computer-readable storage medium. The storage medium non-temporarily stores a computer-readable program. The storage medium can be provided by a semiconductor memory, a magnetic disk, or the like. The control device can be provided by one computer or a set of computer resources linked by a data communication device. When the program is executed by the control device, the control device functions as the device described in this specification and causes the control device to execute the method described in this specification. The control device provides various elements. At least some of those elements can be referred to as means for performing functions, and from another perspective, at least some of those elements can be referred to as structural blocks or modules.

[0093] Note that the means and / or functions provided by the battery ECU 10 can be provided by software recorded in a physical memory device and a computer that executes it, software only, hardware only, or a combination thereof. For example, when the battery ECU 10 is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a number of logic circuits or an analog circuit.

[0094] The preferred embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

Description of Reference Numerals

[0095] 1... microcomputer, 21~2n... first to nth monitoring ICs, 10... battery ECU, 20... main battery, 201~20n... first to nth battery cells, 30... auxiliary battery

Claims

1. An in-vehicle battery control device that controls a battery pack (20) including a plurality of battery cells (201 to 20n) including a plurality of even cells and a plurality of odd cells, Connected to the battery pack to supply power, including a plurality of equalization switches (111 to 113) connected in series, and a plurality of monitoring ICs (21 to 2n) that equalize the voltages of the plurality of battery cells, It can take a state where it is not started and repeats normal operation and standby operation periodically, is powered by an auxiliary battery (30), and includes a microcomputer (1) that gives control instructions to the plurality of monitoring ICs during the normal operation, The monitoring IC, As the plurality of equalization switches, includes a plurality of even switches provided corresponding to the even cells and a plurality of odd switches provided corresponding to the odd cells, The microcomputer dynamically determines a switching time for switching a control target to be turned on between the even switch and the odd switch based on the variation in each cell voltage of the battery cells, and gives a control instruction including the switching time to the monitoring IC, When an equalization instruction is given from the microcomputer, the monitoring IC switches the control target to be turned on between the even switch and the odd switch to perform the voltage equalization in a situation where the microcomputer is not started, measures the elapsed time based on a count value when the control target is turned on, and when the elapsed time reaches the switching time, switches the control target to be turned on. An in-vehicle battery control device.

2. The in-vehicle battery control device according to claim 1, wherein the monitoring IC uses, as the count value, a value obtained by counting a clock signal generated by an oscillator.

3. The in-vehicle battery control device according to claim 1 or 2, wherein an order in which the monitoring IC starts the voltage equalization is preset for either the even cells or the odd cells.

4. The microcomputer, A voltage acquisition unit (S12) that acquires a cell voltage value of each battery cell detected by the monitoring IC, A storage unit (S13) that stores the acquired cell voltage value, A diagnosis unit (S14) that performs a failure diagnosis of the monitoring IC, The diagnosis unit compares a current value that is the current cell voltage value with a previous value that is the cell voltage value stored during the previous startup, and determines that the monitoring IC has failed when the current value and the previous value do not satisfy a predetermined correspondence relationship. The in-vehicle battery control device according to any one of claims 1 to 3.

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