JP2015139292A - Cell unit and cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell system capable of detecting whether a cell voltage monitoring IC normally has shifted into a sleep mode.SOLUTION: A cell system including a cell voltage monitoring IC which is provided in a block unit and detects voltage of a plurality of unit cells and a cell control unit for controlling the cell voltage monitoring IC transmits a command for commanding an operation mode of the cell voltage monitoring IC to the cell voltage monitoring IC through a communication circuit of a daisy-chain system. A cell voltage monitoring IC at the lowest position, in response to the command, transmits a clock signal to a cell voltage monitoring IC at a higher position, when predetermined time has passed after input of the clock signal; a cell voltage monitoring IC at the highest position transmits the clock signal to a cell voltage monitoring IC at a lower position. The cell control unit measures circulation time until receiving the clock signal, and determines that a cell voltage monitoring IC having not shifted into a sleep mode exists when the circulation time is shorter than that in the case that every cell voltage monitoring IC has shifted into the sleep mode.

Description

  The present invention relates to a battery unit and a battery system.

  Improved battery system performance including battery modules with unit cells connected in series and ECUs (Electronic Control Units) that control them, power saving is the safety and reliability of automobiles It is known to be important for enhancing the etc.

  In particular, in EV (Electric Vehicle) applications, a battery system failure is likely to directly affect the running performance of the vehicle.

  A signal provided from a battery voltage monitoring IC (Integrated Circuit) that is provided for each unit cell and detects the voltage of each unit cell serves as an index for determining a failure of the system.

  There has been disclosed a battery cell monitoring integrated circuit in which an abnormality of a battery cell is detected by monitoring overcharge / overdischarge states of a plurality of battery cells to improve reliability (for example, see Patent Document 1).

  Detection voltage (output signal) that is detected by multiple devices on the high voltage side under the control of the control device on the low voltage side, and is transmitted in order from the high-order IC to the low-order IC. Has been disclosed (see Patent Document 2, for example).

  A storage battery device is disclosed in which a battery management device that controls a switch circuit by mutual communication with a battery monitoring unit switches a control signal between normal mode activation and maintenance mode activation, and performs maintenance inspection safely and easily. (For example, refer to Patent Document 3).

  An assembled battery module is disclosed in which, after the assembled battery monitoring device is incorporated into the secondary battery module, the identification code of the device is automatically assigned, so that individual identification is not required at the time of assembly (for example, Patent Documents). 4).

JP 2011-55702 A JP 2011-50176 A JP 2013-73897 A JP 2012-050272 A

  If the battery voltage monitoring IC is in the activated state (active mode) after turning off the ignition switch (hereinafter referred to as IG-OFF) to make the vehicle inoperable, the power of the battery system is wasted. It will be consumed.

  In order to save power in the battery system, it is preferable that all battery voltage monitoring ICs are in a stopped state (sleep mode) at the time of IG-OFF.

  Therefore, a battery system capable of detecting a failure state in which the battery voltage monitoring IC does not normally shift to the sleep mode and is in the active mode at the time of IG-OFF is required.

  Patent Documents 1 to 4 do not disclose a technique for detecting a failure of the monitoring IC when the operation mode is switched.

  In view of the above problems, an object of the present invention is to provide a battery system that can detect whether or not the battery voltage monitoring IC normally shifts to the sleep mode.

In order to achieve the above object, in one embodiment, a battery system comprises:
A battery configured by connecting a plurality of blocks including a plurality of unit cells in series, a battery voltage monitoring IC that detects the voltage of the unit cell and is provided corresponding to the block, and the battery voltage monitoring IC A battery control unit for controlling the battery, and transmitting a command for instructing an operation mode of the battery voltage monitoring IC from the battery control unit to the battery voltage monitoring IC via a daisy chain communication line In the system,
In response to the command from the battery control unit, the battery voltage monitoring IC lower than the highest level transmits the clock signal on the input side in order from the lower level to the higher level.
The battery voltage monitoring IC at the highest level transmits an output side clock signal to the battery control unit via the battery voltage monitoring IC lower than the highest level,
The battery voltage monitoring IC lower than the highest level transmits the input side clock signal to the upper battery voltage monitoring IC when a predetermined time has elapsed from the input of the input side clock signal,
The battery control unit measures a circulation time from transmission of an input side clock signal to the lowest battery voltage monitoring IC to reception of an output side clock signal from the lowest battery voltage monitoring IC. And
When the circulation time is shorter than when all the battery voltage monitoring ICs are shifted to the sleep mode, it is determined that there is the battery voltage monitoring IC not shifted to the sleep mode. It is characterized by.

  According to the present embodiment, it is possible to provide a battery system that can detect whether or not the battery voltage monitoring IC normally shifts to the sleep mode.

It is a figure which shows an example of a structure of the battery system which concerns on 1st Embodiment. It is a figure which shows an example of operation | movement of the battery system which concerns on 1st Embodiment. It is a figure which shows an example of a structure of the battery system which concerns on 2nd Embodiment. It is a figure which shows an example of operation | movement of the battery system which concerns on 2nd Embodiment. It is a figure which shows an example of the flowchart of the battery system which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

  In this specification, the “ignition switch” refers to a switch that starts or stops the engine of the vehicle.

  In addition, “ignition on (IG-ON)” means turning on an ignition switch in order to start the vehicle (to enable running), and “ignition off (IG-OFF)” This means that the ignition switch is turned off in order to stop the vehicle (make it impossible to travel).

<First Embodiment>
[Battery system configuration]
FIG. 1 shows an example of a schematic configuration of the battery system according to the present embodiment. In FIG. 1, a configuration in which four A / D converters are provided in each battery voltage monitoring IC is shown as an example, but the number of A / D converters is not particularly limited. In FIG. 1, a configuration in which four unit cells are provided in each block 60 (60_1 to 60_n) is shown as an example, but the number of unit cells is not particularly limited. The number of unit cells is preferably adjusted as appropriate according to the application.

  The battery system 10 includes a battery voltage monitoring IC unit 11, a battery 12, a battery control unit 13, and an isolator 14 (also referred to as an insulation interface or an insulation device). The battery voltage monitoring IC unit 11 includes a plurality of battery voltage monitoring ICs 50 (50_1 to 50_n), and each battery voltage monitoring IC includes a plurality of A / D converters 51 (51_1 to 51_n) and 52 (52_1 to 52_1). 52_n), 53 (53_1 to 53_n), 54 (54_1 to 54_n). The battery 12 includes a plurality of blocks 60 (60_1 to 60_n), and each block includes a plurality of unit cells 61 (61_1 to 61_n), 62 (62_1 to 62_n), 63 (63_1 to 63_n), 64 ( 64_1 to 64_n). The battery control unit 13 includes a main microcomputer 30 and the like.

  The plurality of unit cells 61 to 64 are connected in series, and the configuration of each unit cell is substantially the same. The plurality of blocks 60 are connected in series, and the configuration of each block is substantially the same. The plurality of battery voltage monitoring ICs 50 are connected in series, and the configuration of each battery voltage monitoring IC is substantially the same. Each battery voltage monitoring IC is provided corresponding to each block.

  The battery voltage monitoring IC unit 11 and the battery 12 constitute a battery unit 15 (may be referred to as a battery pack or the like). The battery unit 15 (high voltage side) and the battery control unit 13 (low voltage side) are electrically insulated via the isolator 14. By setting the battery control unit 13 side to a lower voltage than the battery unit 15 side, it is possible to reduce the burden caused by the voltage applied to the battery control unit 13.

  The main signals transmitted from the battery control unit 13 to the battery unit 15 are a transmission data (TXD) signal and a transmission clock (TX_CLK) signal. The main signal that the battery control unit 13 receives from the battery unit 15 is a reception data (RXD) signal.

  The TXD signal and the TX_CLK signal (in the configuration shown in FIG. 1, these signals are superposed) are connected to each other in the battery voltage monitoring IC unit 11 via a daisy chain type SDI (communication line: Serial Digital Interface). The data is sequentially transmitted to the battery voltage monitoring IC. That is, the TXD signal and the TX_CLK signal are sequentially transmitted from the lowest battery voltage monitoring IC (50_1) to the highest battery voltage monitoring IC (50_n).

  The TXD signal is a signal for controlling each battery voltage monitoring IC based on a command from the battery control unit 13. The RXD signal is a signal that serves as a reference for the battery control unit 13 to determine the state of each battery voltage monitoring IC.

  Note that when the TXD signal and the TX_CLK signal are superimposed, it is not necessary to provide a separate clock signal line, and the number of isolators can be reduced by reducing the number of wirings. For this reason, cost reduction of a battery system can be achieved. On the other hand, when the TXD signal and the TX_CLK signal are not superimposed, the communication accuracy between the battery control unit 13 and the battery unit 15 can be improved. Therefore, when supporting high-speed communication, it is preferable not to superimpose the TXD signal and the TX_CLK signal.

  Examples of the command include an instruction to change the operation mode of each battery voltage monitoring IC, an instruction to detect the voltage of each unit cell, and the like. Examples of the operation mode include an active mode, a sleep mode, a standby mode, and the like. Of these operation modes, the sleep mode is a mode with low power consumption. More specifically, the standby mode is an operation mode that consumes less power than the active mode, and the sleep mode is an operation mode that consumes less power than the standby mode.

  Although details will be described later, in the battery system 10, in response to a command (instruction to shift each battery voltage monitoring IC to the standby mode) transmitted from the battery control unit 13 via the daisy chain communication line. The battery voltage monitoring ICs lower than the highest level transmit the input side clock signal in order from the lower level to the higher level.

  Specifically, the battery voltage monitoring ICs other than the highest and lowest are the higher battery voltage monitoring ICs when a predetermined time elapses from the input of the clock signal on the input side transmitted from the lower battery voltage monitoring ICs. Transmit the clock signal on the input side. The lowest battery voltage monitoring IC transmits the input side clock signal to the upper battery voltage monitoring IC when a predetermined time elapses after the input side clock signal transmitted from the battery control unit 13 is input. The predetermined time is a time required for the battery voltage monitoring IC to shift from the sleep mode to the standby mode.

  When the battery voltage monitoring IC is in the sleep mode at the time of IG-OFF, the battery voltage monitoring IC is connected to the upper battery from the input clock signal input from the lower battery voltage monitoring IC. It takes about several milliseconds (predetermined time A) to transmit the input side clock signal to the voltage monitoring IC.

  On the other hand, when the battery voltage monitoring IC is not in the sleep mode (for example, in the standby mode) at the time of IG-OFF, the battery voltage monitoring IC is input from the lower battery voltage monitoring IC. As soon as this clock signal is input, the input-side clock signal is transmitted to the host battery voltage monitoring IC. At this time, substantially no time (predetermined time B) is required.

  The predetermined time B is shorter than the predetermined time A. That is, the battery system can detect whether or not the battery voltage monitoring IC normally shifts to the sleep mode using the time difference generated between the predetermined time A and the predetermined time B.

  When the input-side clock signal is input, the uppermost battery voltage monitoring IC switches the clock signal to the output-side clock signal. The uppermost battery voltage monitoring IC finally transmits the clock signal on the output side to the lowermost battery voltage monitoring IC via the lower battery voltage monitoring IC. The clock signal on the input side and the clock signal on the output side are transmitted to each battery voltage monitoring IC via a daisy chain communication line.

  The battery voltage monitoring IC at the lowest level takes the time from the output of the clock signal on the input side to the upper battery voltage monitoring IC to the input of the clock signal on the output side transmitted from the upper battery voltage monitoring IC. measure. That is, in this embodiment, the time from when the input-side clock signal is output to the upper battery voltage monitoring IC until the output-side clock signal is input from the upper battery voltage monitoring IC is “circulated”. It is defined as “time”.

  Each battery voltage monitoring IC is preferably in a sleep mode at the time of IG-OFF in order to reduce power consumption. Therefore, in the present embodiment, the circulation time when it is assumed that all battery voltage monitoring ICs are in the sleep mode at the time of IG-OFF is defined as “normal circulation time”.

  According to the battery system 10 of the present embodiment, the lowest battery voltage monitoring IC measures the “circulation time”, so that the battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF can be obtained. It can be determined whether or not it exists.

  In other words, if the “circulation time” coincides with the “normal circulation time”, the lowest battery voltage monitoring IC is “all battery voltage monitoring ICs have shifted to the sleep mode at the time of IG-OFF”. (Normal state) ”. Further, if the “circulation time” is shorter than the “normal circulation time”, the lowest battery voltage monitoring IC is “the battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF” exists. (Failure state) ”.

  The lowest battery voltage monitoring IC transmits the determined information (normal state or failure state) to the outside (in this case, the battery control unit 13). The term “outside” is not limited to the battery control unit 13, but means any device, device, or the like that can control the battery unit 15 based on the information.

  The battery control unit 13 performs fail-safe processing when a failure state is detected based on information received from the lowest-order battery voltage monitoring IC. The fail-safe process is a process for alerting that a failure state has been detected, for example. Thereby, the wasteful power consumption of the battery system 10 can be prevented while the battery system 10 is always operated in a safe and reliable state.

  The battery voltage monitoring IC unit 11 includes a plurality of battery voltage monitoring ICs, and is connected to the battery control unit 13 via an isolator 14. Each battery voltage monitoring IC can detect the voltage of each block by detecting the voltage of a plurality of unit cells. For example, the battery voltage monitoring IC 50_1 can detect the output voltages of the four unit cells 61_1 to 64_1 partitioned as the block 60_1. When detecting the voltage, the A / D converters 51, 52, 53, and 54 are used to convert the detection voltage (analog signal) into a digital signal. At this time, a reference power source for an A / D converter that supplies a reference voltage to the A / D converter may be used.

  Each battery voltage monitoring IC may include a power supply circuit, a control unit, a communication I / F, and the like in addition to the A / D converter. The power supply circuit generates a predetermined voltage based on the power output from the unit cell. The control unit generally controls the battery voltage monitoring IC. For example, the battery voltage monitoring IC is operated based on a command from the main microcomputer 30, data input to one communication I / F, a command, etc. are output from the other communication I / F, a digital signal is stored in a memory, It is possible to perform control such as temporarily storing in a register or the like, and transmitting a detection voltage to the main microcomputer 30.

  Since the battery 12 serves as a power source (battery) for driving an electric motor in an electric vehicle or a hybrid vehicle (HV: Hybrid Vehicle), the battery 12 includes a plurality of unit cells connected in series and can generate a high voltage. A voltage battery is preferred.

  For example, a high voltage can be created by connecting a plurality of unit cells of secondary batteries (storage batteries) such as nickel metal hydride batteries and lithium batteries in series. The electromotive voltage is preferably about 2.3 to 4.2 V per unit cell. The number of unit cells connected in series is preferably about 40 to 90.

  The battery control unit 13 executes a control program or the like stored in a RAM (Random Access Memory) or a ROM (Read Only Memory) built in the main microcomputer 30. The main processing related to the monitoring of the state of the battery 12 is repeated with the main microcomputer 30 as the center. The battery control unit 13 has a sensing function for grasping the state of the battery 12, a function for calculating the state of the battery 12 from the acquired information (for example, RXD signal), and an external device (for example, for battery voltage monitoring) based on the calculation result. A function of controlling the IC unit 11).

  The isolator 14 electrically insulates the battery voltage monitoring IC unit 11 and the battery control unit 13 and transmits a signal only in one direction. For example, the TX_CLK signal and the TXD signal are transmitted from the battery control unit 13 to the battery voltage monitoring IC unit 11. For example, the RXD signal is transmitted from the battery voltage monitoring IC unit 11 to the battery control unit 13. By inserting the isolator 14 between the battery voltage monitoring IC unit 11 and the battery control unit 13, it is possible to prevent backflow of the output signal and the like, and to maintain high reliability of each element.

[Battery system operation]
The operation of the battery system according to one embodiment of the present invention will be described with reference to FIG. In the battery system 10, the main body that measures the “circulation time” is the lowest battery voltage monitoring IC. The TXD signal and the TX_CLK signal are superimposed.

  The operation of the battery system 10 is executed by processing in the following order (1) to (4). In FIG. 2, as an example, a case where three battery voltage monitoring ICs are used in the battery voltage monitoring IC unit 11 will be described. However, the number of battery voltage monitoring ICs is not particularly limited. Absent.

(1) Instruction for transition to standby mode First, the lowest-order battery voltage monitoring IC (battery voltage monitoring IC 50_1) receives an instruction for transition of each battery voltage monitoring IC from the battery control unit 13 to standby mode.

  The battery voltage monitoring IC 50_1 confirms the input clock signal input from the battery control unit 13 and shifts from the sleep mode to the standby mode.

(2) Transition of the battery voltage monitoring IC lower than the highest level to the standby mode Next, when the battery voltage monitoring IC 50_1 shifts to the standby mode (predetermined time has elapsed), the input side clock signal is sent to the upper battery. Transmit to the voltage monitoring IC (battery voltage monitoring IC 50_2) (start of counting up).

  The battery voltage monitoring IC 50_2 confirms the input clock signal input from the battery voltage monitoring IC 50_1 and shifts from the sleep mode to the standby mode.

(3) Transition of Standby Battery Voltage Monitoring IC to Standby Mode Next, when the battery voltage monitoring IC 50_2 transitions to standby mode (predetermined time has elapsed), the input-side clock signal is converted to the highest battery voltage monitoring IC. Transmit to the monitoring IC (battery voltage monitoring IC 50_3).

  The battery voltage monitoring IC 50_3 confirms the input clock signal input from the battery voltage monitoring IC 50_2 and shifts from the sleep mode to the standby mode.

  That is, in response to the instruction from the battery control unit 13 in (1), the battery voltage monitoring ICs lower than the highest level transmit the input side clock signal in order from the lower level to the higher level.

  Here, if the battery voltage monitoring IC 50_2 shifts to the sleep mode at the time of IG-OFF, the battery voltage monitoring IC 50_2 confirms the input of the input side clock signal transmitted from the battery voltage monitoring IC 50_1. Then, when a predetermined time has elapsed, the input side clock signal is transmitted to the battery voltage monitoring IC 50_3. However, if the battery voltage monitoring IC 50_2 has not shifted to the sleep mode at the time of IG-OFF, the battery voltage monitoring IC 50_2 receives the input side clock signal transmitted from the battery voltage monitoring IC 50_1, Immediately, the clock signal on the input side is transmitted to the battery voltage monitoring IC 50_3 (substantially, no time is required).

(4) Measurement of circulation time Next, the battery voltage monitoring IC 50_3 switches the clock signal on the input side to the clock signal on the output side after shifting to the standby mode. Then, the output side clock signal is transmitted to the battery voltage monitoring IC 50_1 via the battery voltage monitoring IC 50_2.

  The battery voltage monitoring IC 50_1 confirms the input of the output side clock signal transmitted from the battery voltage monitoring IC 50_2 (end of counting up). Furthermore, the battery voltage monitoring IC 50_1 measures the time (circulation time) from the start of the count up to the end of the count up. The battery voltage monitoring IC 50_2 does not switch the input-side clock signal to the output-side clock signal.

  The battery control unit 13 receives the RXD signal from the battery voltage monitoring IC 50_1, so that “all battery voltage monitoring ICs have shifted to the sleep mode (normal state) at the time of IG-OFF” or “IG It can be determined whether or not there is a battery voltage monitoring IC that has not shifted to the sleep mode at the time of OFF (failure state). In other words, the RXD signal includes information on whether the “circulation time” matches the “normal circulation time” or is shorter than the “normal circulation time”.

  The battery control unit 13 determines whether or not there is a failure state based on the signal received from the battery voltage monitoring IC 50_1, and performs fail-safe processing if necessary.

  The battery unit 15 can determine whether or not there is a battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF by the above-described operation. Power saving can be achieved.

<Second Embodiment>
In this embodiment, an example of a battery system different from the first embodiment will be described. The configuration and operation of the battery system 20 will be described with reference to FIGS. 3 and 4.

  In the battery system 20, main signals transmitted from the battery control unit 13 to the battery unit 15 are a transmission data (TXD) signal and a transmission clock (TX_CLK) signal. Main signals that the battery control unit 13 receives from the battery unit 15 are a reception data (RXD) signal and a reception clock (RX_CLK) signal. By not superimposing the TXD signal and the TX_CLK signal as in the configuration of FIG. 3, it is possible to prevent deterioration in communication accuracy even when a battery voltage monitoring IC that cannot support high-speed communication is used.

  In the battery system 20, in response to a command (instruction to shift each battery voltage monitoring IC to the standby mode) transmitted from the battery control unit 13 via the daisy chain communication line, The battery voltage monitoring IC transmits the clock signal on the input side in order from the lower order to the higher order.

  Specifically, the battery voltage monitoring ICs other than the highest and lowest are the higher battery voltage monitoring ICs when a predetermined time elapses from the input of the clock signal on the input side transmitted from the lower battery voltage monitoring ICs. Transmit the clock signal on the input side. The lowest battery voltage monitoring IC transmits the input side clock signal to the upper battery voltage monitoring IC when a predetermined time elapses after the input side clock signal transmitted from the battery control unit 13 is input.

  When the input-side clock signal is input, the uppermost battery voltage monitoring IC switches the clock signal to the output-side clock signal. The uppermost battery voltage monitoring IC finally transmits the output-side clock signal to the battery control unit 13 via the lowermost battery voltage monitoring IC.

  The battery control unit 13 measures the time from the transmission of the input-side clock signal to the lowest-order battery voltage monitoring IC to the reception of the output-side clock signal from the lowest-order battery voltage monitoring IC. That is, in the present embodiment, the time from when the battery control unit 13 transmits the TX_CLK signal to the lowest battery voltage monitoring IC to when the RX_CLK signal is received from the lowest battery voltage monitoring IC is “ It is defined as “circulation time” (different from the circulation time according to the first embodiment).

  Each battery voltage monitoring IC is preferably in a sleep mode at the time of IG-OFF in order to reduce power consumption. Therefore, in the present embodiment, the circulation time when it is assumed that all the battery voltage monitoring ICs are in the sleep mode at the time of IG-OFF is defined as “normal circulation time” (in the first embodiment). Different from the normal circulation time).

  According to the battery system 20 of the present embodiment, the battery control unit 13 measures the “circulation time”, so that there is a battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF. You can determine whether or not.

  That is, when the “circulation time” matches the “normal circulation time”, the battery control unit 13 has “all battery voltage monitoring ICs have shifted to the sleep mode at the time of IG-OFF (normal state)”. Can be determined. In addition, when the “circulation time” is shorter than the “normal circulation time”, the battery control unit 13 has “the battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF” (failure state). ) ”.

  The battery control unit 13 performs fail-safe processing when a failure state is detected based on the circulation time. Thereby, the power saving of the battery system 20 can be achieved while maintaining high reliability.

[Battery system operation]
The operation of the battery system according to one embodiment of the present invention will be described with reference to FIG. In the battery system 20, the main body that measures the “circulation time” is the battery control unit 13. The TXD signal and the TX_CLK signal are not superimposed.

  The operation of the battery system 20 is executed by processing in the following order (1) to (4). In FIG. 4, as an example, a case where three battery voltage monitoring ICs are used in the battery voltage monitoring IC unit 11 will be described. However, the number of battery voltage monitoring ICs is not particularly limited. Absent.

(1) Instruction for transition to standby mode First, the battery control unit 13 transmits an input side clock signal (TX_CLK signal) to the lowest battery voltage monitoring IC (battery voltage monitoring IC 50_1) (counting up) start). That is, the instruction to shift to the standby mode is that the lowest battery voltage monitoring IC receives the TX_CLK signal. The battery control unit 13 also transmits a TXD signal to the battery voltage monitoring IC 50_1 at the same time.

  The battery voltage monitoring IC 50_1 receives from the battery control unit 13 an instruction to shift each battery voltage monitoring IC to the standby mode.

  The battery voltage monitoring IC 50_1 confirms the input clock signal input from the battery control unit 13 and shifts from the sleep mode to the standby mode.

(2) Transition of the battery voltage monitoring IC lower than the highest level to the standby mode Next, when the battery voltage monitoring IC 50_1 shifts to the standby mode (predetermined time has elapsed), the input side clock signal is sent to the upper battery. Transmit to the voltage monitoring IC (battery voltage monitoring IC 50_2).

  The battery voltage monitoring IC 50_2 confirms the input clock signal input from the battery voltage monitoring IC 50_1 and shifts from the sleep mode to the standby mode.

(3) Transition of Standby Battery Voltage Monitoring IC to Standby Mode Next, when the battery voltage monitoring IC 50_2 transitions to standby mode (predetermined time has elapsed), the input-side clock signal is converted to the highest battery voltage monitoring IC. Transmit to the monitoring IC (battery voltage monitoring IC 50_3).

  The battery voltage monitoring IC 50_3 confirms the input clock signal input from the battery voltage monitoring IC 50_2 and shifts from the sleep mode to the standby mode.

  That is, in response to the instruction from the battery control unit 13 in (1), the battery voltage monitoring ICs lower than the highest level transmit the input side clock signal in order from the lower level to the higher level.

  The battery voltage monitoring ICs lower than the highest level also transmit TXD signals in order from the lower level to the higher level.

(4) Measurement of circulation time Next, the battery voltage monitoring IC 50_3 switches the clock signal on the input side to the clock signal on the output side after shifting to the standby mode. Then, the output side clock signal is transmitted to the battery voltage monitoring IC 50_1 via the battery voltage monitoring IC 50_2. Similarly, the battery voltage monitoring IC 50_3 switches the TXD signal on the input side to the RXD signal on the output side. Then, the RXD signal is transmitted to the battery voltage monitoring IC 50_1 via the battery voltage monitoring IC 50_2.

  The battery control unit 13 receives the output-side clock signal from the battery voltage monitoring IC 50_1 (end of counting up). Furthermore, the battery control unit 13 measures the time (circulation time) from the start of the count up to the end of the count up. Note that the battery voltage monitoring IC 50_2 does not switch the input side clock signal and the TXD signal to the output side clock signal and the RXD signal.

  If the “circulation time” matches the “normal circulation time”, the battery control unit 13 indicates that “all battery voltage monitoring ICs have shifted to the sleep mode (normal state) at the time of IG-OFF”. I can judge. In addition, when the “circulation time” is shorter than the “normal circulation time”, the battery control unit 13 has “the battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF” (failure state). ) ”. In other words, the battery control unit 13 determines whether or not it is a failure state by measuring the circulation time, and performs fail-safe processing when a failure state is detected.

  The battery system 20 can determine whether or not there is a battery voltage monitoring IC that has not shifted to the sleep mode at the time of IG-OFF by the above-described operation, and therefore wasteful power consumption of the battery unit 15 even during long-term storage. Can be prevented. Further, even when a battery voltage monitoring IC that is relatively incompatible with high-speed communication is used, it is possible to save power in the battery system without deteriorating communication accuracy.

  Next, the operation of the battery system according to one embodiment of the present invention will be described using the control flowchart of FIG. i is the counter value of the counter. K is a value determined by the number of connected battery voltage monitoring ICs in the daisy chain.

  In step SS500, the battery control unit 13 recognizes IG-ON.

  When the battery control unit 13 recognizes IG-ON (Yes), the process proceeds to step S501. When the battery control unit 13 does not recognize IG-ON (No), the process proceeds to step S503 (return to RETURN: START). .

  In step SS501, the battery control unit 13 sets the counter value i to i = 0.

  In step S502, the battery control unit 13 transmits an input-side clock signal (TX_CLK signal) to the lowest-order battery voltage monitoring IC (start of counting up).

  In step S504, the battery control unit 13 increases the counter value i.

  In step S505, the battery control unit 13 determines whether an output-side clock signal is received from the lowest battery voltage monitoring IC.

  When the battery control unit 13 receives the clock signal on the output side from the lowest battery voltage monitoring IC (Yes), the battery control unit 13 proceeds to step S506 (end of counting up). On the other hand, if the battery control unit 13 does not receive the output-side clock signal from the lowest battery voltage monitoring IC (No), the process returns to step S504.

  In step S506, the battery control unit 13 compares i and k.

  If i is greater than or equal to k, the battery control unit 13 proceeds to step S507. If i is smaller than k, the battery control unit 13 proceeds to step S508.

  In step S507, the battery control unit 13 determines from the comparison result between i and k that all the battery voltage monitoring ICs have shifted to the sleep mode at the time of the previous IG-OFF. That is, when i ≧ k, the battery control unit 13 can determine that all the battery voltage monitoring ICs have shifted to the sleep mode (normal state) at the time of IG-OFF.

  In step S508, the battery control unit 13 determines from the comparison result between i and k that there is a battery voltage monitoring IC that has not shifted to the sleep mode. That is, when i <k, the battery control unit 13 can determine that there is a battery voltage monitoring IC that has not shifted to the sleep mode when IG-OFF (failure state).

  In step S509, the battery control unit 13 transmits a caution output, that is, information indicating that there is a battery voltage monitoring IC that has not shifted to the sleep state.

  Therefore, the battery control unit 13 can determine whether or not the battery system is in a failure state through the above-described steps S500 to S509, and can perform fail-safe processing when a failure state is detected.

  In the flowchart shown in FIG. 5, the case where the main body that measures “circulation time” is the battery control unit 13 has been described, but the present invention is not particularly limited to this case. For example, even when the main body that measures the “circulation time” is the lowest battery voltage monitoring IC, the battery system can detect a failure by the same operation as in step S described above.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

10, 20 Battery system 12 Battery 13 Battery control unit 14 Isolator 15 Battery unit 50 Battery voltage monitoring IC
60 blocks 61, 62, 63, 64 unit cells

Claims (4)

A battery configured by connecting a plurality of blocks including a plurality of unit cells in series, a battery voltage monitoring IC that detects the voltage of the unit cell and is provided corresponding to the block, and the battery voltage monitoring IC A battery control unit for controlling the battery, and transmitting a command for instructing an operation mode of the battery voltage monitoring IC from the battery control unit to the battery voltage monitoring IC via a daisy chain communication line In the system,
In response to the command from the battery control unit, the battery voltage monitoring IC lower than the highest level transmits the clock signal on the input side in order from the lower level to the higher level.
The battery voltage monitoring IC at the highest level transmits an output side clock signal to the battery control unit via the battery voltage monitoring IC lower than the highest level,
The battery voltage monitoring IC lower than the highest level transmits the input side clock signal to the upper battery voltage monitoring IC when a predetermined time has elapsed from the input of the input side clock signal,
The battery control unit measures a circulation time from transmission of an input side clock signal to the lowest battery voltage monitoring IC to reception of an output side clock signal from the lowest battery voltage monitoring IC. And
A battery for determining that there is an IC for monitoring the battery voltage that has not entered the sleep mode when the circulation time is shorter than when all of the battery voltage monitoring ICs have entered the sleep mode; system.   The battery system according to claim 1, wherein the battery voltage monitoring IC and the battery control unit are electrically insulated through an isolator. A battery configured by connecting a plurality of blocks including a plurality of unit cells in series; and a battery voltage monitoring IC that detects a voltage of the unit cell and is provided corresponding to the block; and the battery voltage In a battery unit that transmits a command for instructing an operation mode of the monitoring IC to the battery voltage monitoring IC via a daisy chain communication line.
In response to the command, the battery voltage monitoring IC lower than the highest level transmits the clock signal on the input side in order from the lower level to the higher level.
The uppermost battery voltage monitoring IC transmits an output side clock signal to the lowermost battery voltage monitoring IC via the battery voltage monitoring IC lower than the highest level,
The battery voltage monitoring IC lower than the highest level transmits the input side clock signal to the upper battery voltage monitoring IC when a predetermined time has elapsed from the input of the input side clock signal,
The battery voltage monitoring IC at the lowest level measures a circulation time from the output of the input side clock signal to the input of the output side clock signal,
A battery for determining that there is an IC for monitoring the battery voltage that has not entered the sleep mode when the circulation time is shorter than when all of the battery voltage monitoring ICs have entered the sleep mode; unit.   The battery unit according to claim 3, wherein the lowest battery voltage monitoring IC transmits information indicating that the battery voltage monitoring IC that has not shifted to the sleep state exists to the outside.

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