Patent Publication Number: US-2023155185-A1

Title: Control apparatus and battery pack

Description:
This application is based on Japanese patent application NO. 2021-186868, filed on Nov. 17, 2021, the content of which is incorporated hereinto by reference. 
     BACKGROUND 
     Technical Field 
     The present invention relates to control of relays. 
     Related Art 
     A battery pack in which a plurality of batteries are connected is used to supply power to various loads. At this time, a relay is disposed between the battery and the load, and ON/OFF of the relay is controlled by a relay drive circuit. 
     Here, some control elements used in a drive circuit can diagnose the state of an output destination of a signal. By diagnosing the state of the output destination, it is possible to detect whether the relay has failed. 
     Japanese Unexamined Patent Publication No. 2007-27465 discloses that, in a drive circuit of a linear solenoid, that includes an asymmetrical bridge, two diagnostic results are input to a control unit, and operation states of an asymmetrical half-bridge circuit and the linear solenoid are determined based on the diagnostic results. 
     Japanese Unexamined Patent Publication No. 2007-255413 discloses that an abnormality in a load driving system is diagnosed based on a result obtained by comparing a control signal input to a driver and a monitor signal output from an abnormality detection unit. 
     SUMMARY 
     However, there is room for improving the reliability of a control apparatus of the relay. For example, in the technique in Japanese Unexamined Patent Publication No. 2007-27465, the failure of an intelligent power switch is not assumed. In addition, in the technique in Japanese Unexamined Patent Publication No. 2007-255413, the output signal from the driver to the load is not monitored. 
     The present invention has been made in view of the above problems. An object of the present invention to provide a technique for improving the reliability of abnormality detection in a control apparatus of a relay. 
     In one embodiment, there is provided a first control apparatus that is a control apparatus that controls a relay. The control apparatus includes a control element that receives an input signal and outputs an output signal and a diagnostic signal, a monitoring circuit that generates an output monitor signal indicating the level of the output signal, and a determination unit that determines whether or not the control apparatus has an abnormality, based on a relationship between the output monitor signal and the diagnostic signal. 
     The output signal is a signal for driving the relay. 
     One terminal of the monitoring circuit is electrically connected to an output terminal of the control element for the output signal. 
     The diagnostic signal is a signal for monitoring the state of the output destination of the output signal. 
     In another embodiment, there is provided a first battery pack that is a battery pack including the control apparatus as described above, a battery, and the relay. 
     According to the present invention, it is possible to provide a technique for improving the reliability of abnormality detection in a control apparatus of a relay. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, advantages and features of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a block diagram illustrating a functional configuration of a control apparatus according to a first embodiment. 
         FIG.  2    is a diagram illustrating a hardware configuration of the control apparatus according to the first embodiment. 
         FIG.  3    is a diagram illustrating a hardware configuration of an integrated circuit. 
         FIG.  4    is a table illustrating a relationship of each signal in a normal control apparatus. 
         FIG.  5    is a table obtained by adding the relationship of each signal when a control element has an abnormality, and a diagnostic signal is not correctly output, to the table in  FIG.  4   . 
         FIG.  6    is a table obtained by adding the relationship of each signal when a monitoring circuit has an abnormality, and an output monitor signal is not correctly output, to the table in  FIG.  4   . 
         FIG.  7    is a block diagram illustrating a functional configuration of a battery pack according to the first embodiment. 
         FIG.  8    is a diagram illustrating a configuration of a battery pack according to a second embodiment. 
         FIG.  9    is a diagram illustrating a configuration of a control apparatus according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will be now described herein with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes. 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are denoted by the similar reference signs, and description thereof will not be repeated. 
     First Embodiment 
       FIG.  1    is a block diagram illustrating a functional configuration of a control apparatus  10  according to a first embodiment.  FIG.  2    is a diagram illustrating a hardware configuration of the control apparatus  10  according to the present embodiment. The control apparatus  10  according to the present embodiment is an apparatus that controls a relay  20 . The control apparatus  10  includes a control element  12 , a monitoring circuit  14 , and a determination unit  16 . An input signal Vi is input to the control element  12 . The control element  12  outputs an output signal Vo and a diagnostic signal Vd. The monitoring circuit  14  generates an output monitor signal Vm indicating the level of the output signal Vo. The determination unit  16  determines whether or not the control apparatus  10  has an abnormality, based on a relationship between the output monitor signal Vm and the diagnostic signal Vd. Here, the output signal Vo is a signal for driving the relay  20 . One terminal of the monitoring circuit  14  is electrically connected to an output terminal of the control element  12  for the output signal Vo. The diagnostic signal Vd is a signal for monitoring the state of an output destination of the output signal Vo. A detailed description will be made below. 
     In the example in  FIG.  1   , the control apparatus  10  further includes a control unit  15 . The control unit  15  outputs an input signal Vi. The input signal Vi output from the control unit  15  is input to the control element  12 . The control unit  15  and determination unit  16  are implemented by using an integrated circuit  40 , for example. The integrated circuit  40  will be described later in detail. The input signal Vi output from the control unit  15  is also input to the determination unit  16 . The determination unit  16  may acquire information indicating a signal level of the input signal Vi from the control unit  15  instead of inputting the input signal Vi to the determination unit  16 . The input and output of signals and information between the control unit  15  and the determination unit  16  may be performed within the integrated circuit  40 . 
       FIG.  3    is a diagram illustrating a hardware configuration of the integrated circuit  40 . In  FIG.  3   , the control unit  15  and the determination unit  16  in the control apparatus  10  are implemented by an integrated circuit  40 . The integrated circuit  40  is, for example, a system on chip (SoC). 
     The integrated circuit  40  includes a bus  402 , a processor  404 , a memory  406 , a storage device  408 , an input/output interface  410 , and a network interface  412 . The bus  402  is a data transmission line for the processor  404 , the memory  406 , the storage device  408 , the input/output interface  410 , and the network interface  412  to transmit and receive data to and from each other. A method of connecting the processors  404  and the like to each other is not limited to the bus connection. The processor  404  is an arithmetic processing unit realized using a microprocessor or the like. The memory  406  is a memory realized using a random access memory (RAM) or the like. The storage device  408  is a storage device realized using a read only memory (ROM), a flash memory, or the like. 
     The input/output interface  410  is an interface for connecting the integrated circuit  40  to peripheral devices. In the present embodiment, at least the control element  12  and the monitoring circuit  14  are connected to the input/output interface  410 . 
     The network interface  412  is an interface for connecting the integrated circuit  40  to a communication network. Such a communication network is, for example, a controller area network (CAN) communication network. A method of connecting the network interface  412  to the communication network may be a wireless connection or a wired connection. 
     The storage device  408  stores program modules for implementing the functions of the control unit  15  and the determination unit  16 , respectively. The processor  404  implements the functions of the control unit  15  and the determination unit  16  by reading the program modules into the memory  406  and executing the program modules. 
     The hardware configuration of the integrated circuit  40  is not limited to the configuration illustrated in  FIG.  3   . For example, the program module may be stored in the memory  406 . In this case, the integrated circuit  40  may not include the storage device  408 . 
     The control element  12  is implemented by an integrated circuit. The control element  12  is, for example, an intelligent power device (IPD). The control element  12  outputs an output signal Vo corresponding to the inputted input signal Vi. Furthermore, the control element  12  outputs a diagnostic signal Vd indicating the state of an output destination of the output signal Vo. In the control element  12 , the diagnostic signal Vd is generated in accordance with the result of the determination using the level of the output signal Vo. The diagnostic signal Vd is input to the determination unit  16 . The signal levels of the input signal Vi, the output signal Vo, and the diagnostic signal Vd are each represented by a high level or a low level based on a predetermined threshold value. The input signal Vi and the diagnostic signal Vd are, for example, binary signals. The threshold values may be different values for the input signal Vi, the output signal Vo, and the diagnostic signal Vd, respectively. The control element  12  may further have a function of detecting overheating and a protection function against overheating and overcurrent. 
     The output signal Vo output from the control element  12  is input to the relay  20 . The relay  20  is turned on and off by the output signal Vo. The type of relay  20  is not particularly limited. The relay  20  may be a contact relay or a non-contact relay. The output signal Vo is also input to the monitoring circuit  14 . The monitoring circuit  14  outputs the output monitor signal Vm indicating the level of the input output signal Vo. Although  FIG.  2    illustrates an example in which the monitoring circuit  14  includes a resistor  142  and a transistor  141 , the configuration of the monitoring circuit  14  is not limited to the present example. For example, the monitoring circuit  14  may be configured by a plurality of resistors for dividing the output signal Vo at a predetermined ratio. In this case, the output monitor signal Vm is inverted from the examples illustrated in  FIGS.  4  to  6   . That is, “H” of the output monitor signal Vm illustrated in  FIGS.  4  to  6    may be read as “L”, and “L” may be read as “H”. 
     In the example in this figure, the base terminal of the transistor  141  functions as an input terminal of the monitoring circuit  14 . The output terminal of the control element  12  for the output signal Vo is electrically connected to the base terminal of the transistor  141 . That is, the output terminal for the output signal Vo and the base terminal of the transistor  141  have the same potential. One end of the resistor  142  is connected to the collector terminal of the transistor  141 , and the constant voltage Vdc is applied to the other end of the resistor  142 . On the other hand, the emitter terminal of the transistor  141  is connected to GND. The collector terminal of the transistor  141  is connected to the input/output interface  410  of the integrated circuit  40 . That is, the voltage of the collector terminal of the transistor  141  is input to the determination unit  16  as the output monitor signal Vm. With such a configuration, the output monitor signal Vm indicating the level of the output signal Vo is obtained. 
     In particular, according to the monitoring circuit  14  in the present example, the output monitor signal Vm having a low level with respect to the output signal Vo having a high level is output, and the output monitor signal Vm having a high level with respect to the output signal Vo having a low level is output. The output monitor signal Vm having a high level has the same voltage as the constant voltage Vdc. The output signal Vo for driving the relay  20  may be at an appropriately high voltage. Here, by using the monitoring circuit  14 , it is possible to convert the voltage level of the output signal Vo into a voltage level range in which the voltage can be input into the input/output interface  410  of the integrated circuit  40 . 
       FIG.  4    is a table illustrating a relationship of each signal in the normal control apparatus  10 . In  FIG.  4   , “L” indicates that the signal is at a low level, and “H” indicates that the signal is at a high level. In the present embodiment, the determination unit  16  can determine whether or not the output destination of the output signal Vo has an abnormality, by using the input signal Vi and the diagnostic signal Vd. Specifically, the determination unit  16  can use the input signal Vi and the diagnostic signal Vd to perform at least one of determination of whether or not the output destination of the output signal Vo is in an open state, and determination of whether or not the output destination of the output signal Vo is in a short-circuited state. The output destination of the output signal Vo include the relay  20 , the monitoring circuit  14 , a wiring connecting the control element  12  and the relay  20 , and a wiring connecting the control element  12  and the monitoring circuit  14 . 
     The operation of the control apparatus  10  will be described with reference to  FIG.  4   . First, when the relay  20  is intended to turn into an off state, an input signal Vi having a low level is input from the control unit  15  to the control element  12 . Then, an output signal Vo having a low level is output from the control element  12  to the relay  20  which is normal, and then the relay  20  turns into an off state. At this time, a diagnostic signal Vd output from the control element  12  becomes a low level. Also, an output monitor signal Vm output from the monitoring circuit  14  becomes a high level. 
     On the other hand, when the output destination of the output signal Vo is in an open state, for example, when the relay  20  is disconnected, the output signal Vo becomes a high level with respect to the input signal Vi having a low level. Then, the diagnostic signal Vd output from the control element  12  becomes a high level, and the output monitor signal Vm becomes a low level. 
     When the relay  20  is intended to turn into an on state, the input signal Vi having a high level is input from the control unit  15  to the control element  12 . Then, the output signal Vo having a high level is output from the control element  12  to the relay  20  which is normal, and then the relay  20  turns into an on state. At this time, the diagnostic signal Vd output from the control element  12  becomes a high level. Also, the output monitor signal Vm output from the monitoring circuit  14  becomes a low level. 
     On the other hand, when the output destination of the output signal Vo is in a short-circuited state, the output signal Vo becomes a low level with respect to the input signal Vi having a high level. Then, the diagnostic signal Vd output from the control element  12  becomes a low level, and the output monitor signal Vm becomes a high level. The phrase that the output destination of the output signal Vo is in a short-circuited state means that the output destination is in a short-circuited state with respect to GND. When the control element  12  has an overcurrent prevention function, the current output from the output signal Vo is limited. 
     In each of the states described above, the determination unit  16  determines whether or not the output destination of the output signal Vo has an abnormality, as follows, by monitoring the input signal Vi and the diagnostic signal Vd. When the input signal Vi is at a low level and the diagnostic signal Vd is at a low level, the determination unit  16  determines that the output destination of the output signal Vo has no abnormality and the relay  20  is normally turned off. When the input signal Vi is at a low level and the diagnostic signal Vd is at a high level, the determination unit  16  determines that the output destination of the output signal Vo is in an open state. When the input signal Vi is at a high level and the diagnostic signal Vd is at a high level, the determination unit  16  determines that the output destination of the output signal Vo has no abnormality and the relay  20  is normally turned off. When the input signal Vi is at a high level and the diagnostic signal Vd is at a low level, the determination unit  16  determines that the output destination of the output signal Vo is in a short-circuited state. 
     The determination unit  16  can determine whether or not the control element  12  and the monitoring circuit  14  have an abnormality by monitoring the diagnostic signal Vd and the output monitor signal Vm. A detailed description will be made below. 
       FIG.  5    is a table obtained by adding the relationship of each signal when the control element  12  has an abnormality, and the diagnostic signal Vd is not correctly output, to the table in  FIG.  4   .  FIG.  6    is a table obtained by adding the relationship of each signal when the monitoring circuit  14  has an abnormality and the output monitor signal Vm is not correctly output, to the table in  FIG.  4   . In  FIGS.  5  and  6   , “L” indicates that the signal is at a low level, and “H” indicates that the signal is at a high level. In the present example, when both the control element  12  and the monitoring circuit  14  are normal, the diagnostic signal Vd and the output monitor signal Vm normally have a reversed relationship between a high level and a low level. That is, one of the diagnostic signal Vd and the output monitor signal Vm becomes a high level, and the other becomes a low level. On the other hand, when the control element  12  has an abnormality, the diagnostic signal Vd that needs to be at a high level becomes a low level, or the diagnostic signal Vd that needs to be at a low level becomes a high level. Further, when the monitoring circuit  14  has an abnormality, the output monitor signal Vm that needs to be at a high level becomes a low level, or the output monitor signal Vm that needs to be at a low level becomes a high level. As a result, the relationship between the diagnostic signal Vd and the output monitor signal Vm becomes a matching relationship. As described above, when the relationship between the diagnostic signal Vd and the output monitor signal Vm becomes a matching relationship, the determination unit  16  determines that the control apparatus  10  has an abnormality. 
     The relationship of the signals in the control apparatus  10  is not limited to the examples illustrated in  FIGS.  4  to  6   . The determination unit  16  can compare the input signal Vi and the diagnostic signal Vd, and determine whether or not the output destination of the output signal Vo has an abnormality based on whether or not the input signal Vi and the diagnostic signal Vd satisfy a predetermined relationship. Further, the determination unit  16  can compare the diagnostic signal Vd and the output monitor signal Vm, and determine whether or not the control apparatus  10  has an abnormality, based on whether or not the diagnostic signal Vd and the output monitor signal Vm satisfy a predetermined relationship. In addition, the determination unit  16  may compare the diagnostic signal Vd and the output monitor signal Vm, and further the input signal Vi, and determine whether or not the control apparatus  10  has an abnormality, based on whether or not the diagnostic signal Vd and the output monitor signal Vm, and further the input signal Vi satisfy a predetermined relationship. 
     As described above, the control apparatus  10  according to the present embodiment can detect an occurrence of an abnormality of the relay  20  by using the diagnostic signal Vd of the control element  12 . Even when the diagnostic signal Vd of the control element  12  has a defect due to a failure of the control element  12  or the like, it is possible to detect the occurrence of an abnormality in the control apparatus  10  by using the output monitor signal Vm allowing the output signal Vo to be directly monitored. That is, the control apparatus  10  has a double abnormality detection function, and can improve the reliability of abnormality detection as compared with a case where only the diagnostic signal Vd of the control element  12  is used. 
     The configuration of the control element  12  is usually complicated more than the configuration of the monitoring circuit  14 , and is considered to be prone to failure. Thus, when the determination unit  16  determines that an abnormality has occurred in the control apparatus  10 , it may be determined that the diagnostic signal Vd is abnormal (that is, the abnormal case in  FIG.  5   ). In this case, the determination unit  16  may determine the state of the relay  20  being the output destination of the output signal Vo, based on whether or not the relationship between the input signal Vi and the output monitor signal Vm satisfies a predetermined relationship. 
       FIG.  7    is a block diagram illustrating the functional configuration of a battery pack  50  according to the present embodiment. The battery pack  50  according to the present embodiment includes the control apparatus  10 , a battery  30 , and the relay  20 . The control apparatus  10  and relay  20  are as described above. The battery  30  is not particularly limited, but is, for example, a lithium ion battery. The battery  30  may be a battery module in which one or more battery cells are connected. A plurality of battery cells in the battery  30  may be connected in series or in parallel. In the battery  30 , three or more battery cells may be connected in series and in parallel. Although the use of battery pack  50  is not particularly limited, the battery pack  50  is mounted in a moving body such as a vehicle, for example. 
     The battery pack  50  is connected to a load  60 , and the electrical energy of the battery  30  is supplied to the load  60 . At this time, the electrical connection between the battery  30  and the load  60  is turned on/off by the relay  20  controlled by the control apparatus  10 . The load  60  is not particularly limited, but may be, for example, a motor drive inverter, an inverter such as a household 100V inverter, a heater, a DC-DC converter, or an air conditioner. When the battery  30  is rechargeable, the battery  30  may be configured to be connected to a charger via the relay  20  at least temporarily. The battery pack  50  according to the present embodiment includes the control apparatus  10  capable of detecting an abnormality. Therefore, when it is not possible to correctly control the power supply due to a failure of the control element  12  or the like, it can be detected that it is not possible to correctly control the power supply. 
     Next, the operations and effects of the present embodiment will be described. According to the control apparatus  10  according to the present embodiment, the determination unit  16  determines whether or not the control apparatus  10  has an abnormality, based on the relationship between the output monitor signal Vm and the diagnostic signal Vd. Therefore, it is possible to improve the reliability of abnormality detection as compared with the case where only the diagnostic signal Vd of the control element  12  is used. 
     Second Embodiment 
       FIG.  8    is a diagram illustrating a configuration of a battery pack  50  according to a second embodiment. The battery pack  50  and a control apparatus  10  according to the present embodiment are the same as the battery pack  50  and the control apparatus  10  according to the first embodiment, except for the points described below. 
     The battery pack  50  according to the present embodiment includes a plurality of relays  20 . The control apparatus  10  according to the present embodiment controls the plurality of relays  20 . Specifically, in the example in  FIG.  8   , the battery pack  50  includes a relay  20   a , a relay  20   b , and a relay  20   c . Each of the relays is the same as the relay  20  described in the first embodiment. In the example in  FIG.  8   , the battery  30  is a battery module in which a plurality of battery cells are connected in series. The relays  20   a  and  20   b  turn on/off the connection between the anode of the relay  20  and one terminal of the load  60 , and the relay  20   c  turns on/off the connection between the cathode of the battery  30  and the other terminal of the load  60 . The relay  20   b  and a resistor are connected in parallel with the relay  20   a.    
     In the present embodiment, the control apparatus  10  is included in a battery management system (BMS). The control apparatus  10  controls each relay  20  in accordance with a predetermined sequence. As a result, a desired power supply operation or charging operation is performed while preventing an excessive current or the like. Although  FIG.  8    illustrates an example of the battery pack  50  including three relays  20 , the battery pack  50  may include more relays  20 . 
       FIG.  9    is a diagram illustrating the configuration of the control apparatus  10  according to the present embodiment. In the present embodiment, the control apparatus  10  includes a plurality of control elements  12  and a plurality of monitoring circuits  14  for controlling the plurality of relays  20 . Each control element  12  is the same as the control element  12  described in the first embodiment, and each monitoring circuit  14  is the same as the monitoring circuit  14  described in the first embodiment. Specifically, in the example in  FIG.  9   , the control apparatus  10  includes a control element  12   a , a control element  12   b , a control element  12   c , a monitoring circuit  14   a , a monitoring circuit  14   b , and a monitoring circuit  14   c . Each control element  12  and each monitoring circuit  14  is connected to an integrated circuit  40 . The control unit  15  independently controls each control element  12  to control each relay  20  in accordance with a predetermined sequence. That is, the control unit  15  outputs the input signal Vi to each control element  12  independently. The determination unit  16  acquires the input signal Vi for each control element  12 . In the example in  FIG.  9   , the control unit  15  outputs three input signals Vi. Three input signals Vi are input to the determination unit  16 . Further, the diagnostic signal Vd output from each control element  12  and the output monitor signal Vm output from each monitoring circuit  14  are input to the determination unit  16 . 
     Also in the present embodiment, the same operations and effects as in the first embodiment can be obtained. 
     Hitherto, the embodiment of the present invention has been described above with reference to the drawings, but these are examples of the present invention, and various configurations other than the above description can be adopted. 
     It is apparent that the present invention is not limited to the above embodiment, and may be modified and changed without departing from the scope and spirit of the invention.