Fault detection program and fault detection circuit

Abstract

To solve the problem that the time required for fault detection is long in a conventional fault detection circuit.SOLUTION: A fault detection program executes: coefficient storage processing for storing in a storage section a terminal connection coefficient k[i] which becomes a first value or a second value in accordance with a sensor connection state to a sensor connection terminal; threshold storage processing for storing in the storage section preset first upper limit threshold UL1 and lower limit threshold LL1 and second upper limit threshold UL2 and lower limit threshold LL2 which are obtained by multiplying the first upper limit threshold UL1 and the first lower limit threshold LL1 by the second value; determined value calculation processing (S12) for calculating for each sensor connection terminal a determined value M[i] which is obtained by multiplying a measured value T[i] and the terminal connection coefficient k[i]; and fault detection processing (S13-S26) for performing a fault determination on a sensor connection terminal basis based on a magnitude relation of the determined value M[i], the first upper limit threshold UL1, the first lower limit threshold LL1, the second upper limit threshold UL2 and the second lower limit threshold LL2 for each sensor connection terminal.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a fault detection program and a fault detection circuit that are applied to, for example, a temperature detection device having a plurality of terminals to which a temperature sensor is connected. [Background technology]

[0002] In a battery pack in which multiple battery cells are combined and used as one battery, multiple battery cells arranged in one direction (for example, stacking direction) are restrained by applying pressure from both ends of the stacking direction to form a battery stack. In such a battery stack, it is necessary to measure the temperature of the battery cells in order to keep the battery performance within a certain range. Therefore, the temperature of the battery cells is detected using a temperature detection device or the like, but the number of points at which the temperature is detected varies depending on the specifications of the battery module. Therefore, it is necessary to design a temperature detection device for each battery module specification. However, by using one type of temperature detection device in common for battery modules of multiple specifications, it is possible to reduce the development cost, operation verification cost, and parts management cost of the temperature detection device. In such a temperature detection circuit that is used in common for battery modules of multiple specifications, there may be an excess terminal for connecting a temperature sensor, and it is necessary to prevent malfunction due to the terminal to which the temperature sensor is not connected. Therefore, a technology for determining whether a terminal in an electric circuit having an unused terminal is unused or disconnected is disclosed in Patent Document 1.

[0003] The load driving circuit described in Patent Document 1 utilizes a temperature detection terminal to which the output of a temperature sensor is input, and when a clamp circuit or a part of the temperature detection circuit is not connected to a power module, detects a disconnection invalid state in which the temperature sensor is not connected based on the potential of the temperature detection terminal. For example, by applying a voltage equal to or greater than the disconnection detection invalidation threshold to a terminal of the temperature detection terminal that is not connected to the temperature sensor, it is detected that the temperature detection terminal is not connected to the temperature sensor. As a result, when disconnection detection is performed based on the potential of the clamp terminal connected to the clamp circuit, it is possible to determine whether the state is a disconnection state or a disconnection invalid state according to the potential of the temperature detection terminal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-222724 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the technology described in Patent Document 1, when detecting disconnections in unused terminals, it is necessary to apply a voltage equal to or greater than the disconnection detection disabling threshold to terminals that are not connected to a temperature sensor, and a voltage source is required just to detect disconnections in unused terminals. In such a technology described in Patent Document 1, it is necessary to check for the presence or absence of a fault in the voltage source in order to increase the fault detection level of the system, which causes a problem that fault detection takes time.

[0006] The present invention has been made in consideration of the above circumstances, and has as its object to shorten the time required for fault detection. [Means for solving the problem]

[0007] One aspect of the fault detection program according to the present invention is a fault detection program that is executed by an arithmetic unit and detects faults related to breaks and shorts in a signal path that occur in association with the sensor connection terminals in a temperature detection device having a plurality of sensor connection terminals provided for connecting sensors, the fault detection program including: a coefficient storage process that stores in a memory unit a terminal connection coefficient that has a first value when the sensor is connected to each of the sensor connection terminals and a second value when the sensor is not connected; a threshold storage process that stores in the memory unit a first upper limit threshold and a first lower limit threshold that are set in advance, and a second upper limit threshold and a second lower limit threshold that are obtained by multiplying the first upper limit threshold and the first lower limit threshold by the second value; a measurement value acquisition process that acquires a measurement value obtained from the sensor connection terminal for each of the sensor connection terminals; a determined value calculation process that calculates a determined value for each of the sensor connection terminals by multiplying the measurement value and the terminal connection coefficient; and a fault detection process that performs a fault determination for each of the sensor connection terminals based on the magnitude relationship between the determined value, the first upper limit threshold, the first lower limit threshold, the second upper limit threshold, and the second lower limit threshold.

[0008] One aspect of the fault detection circuit according to the present invention includes a measurement value acquisition unit that acquires, for each of a plurality of sensor connection terminals provided for connecting a sensor, a measurement value obtained from the plurality of sensor connection terminals, the plurality of sensor connection terminals being provided for connecting a sensor; a coefficient storage processing unit that stores in a memory unit a terminal connection coefficient that has a first value when the sensor is connected to the sensor connection terminal and a second value when the sensor is not connected to the sensor; a threshold value storage processing unit that stores in the memory unit a first upper limit threshold and a first lower limit threshold that are set in advance, and a second upper limit threshold and a second lower limit threshold that are obtained by multiplying the first upper limit threshold and the first lower limit threshold by the second value; a determined value calculation unit that calculates, for each of the sensor connection terminals, a determined value that is obtained by multiplying the measurement value and the terminal connection coefficient; and a fault detection unit that performs fault determination for each of the sensor connection terminals based on the magnitude relationship between the determined value, the first upper limit threshold, the first lower limit threshold, the second upper limit threshold, and the second lower limit threshold. Effect of the Invention

[0009] According to the fault detection program and fault detection circuit of the present invention, the time required to detect a short circuit of an unused terminal can be reduced. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a battery unit according to a first embodiment. [Diagram 2] 1 is a block diagram of a temperature detection device according to a first embodiment. [Diagram 3] 1 is a block diagram of a fault detection circuit according to a first embodiment. [Figure 4] 4 is a diagram for explaining a fault determination range in the fault detection circuit according to the first embodiment; FIG. [Diagram 5] 4 is a flowchart illustrating an operation of the failure detection circuit according to the first embodiment. [Figure 6] 10 is a flowchart illustrating an operation of a failure detection circuit according to a comparative example. [Figure 7] 11 is a diagram illustrating a difference in the number of branch processes between the comparative example and the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In order to clarify the description, the following description and drawings are omitted and simplified as appropriate. In addition, each element shown in the drawings as a functional block performing various processes can be configured in hardware with a CPU (Central Processing Unit), memory, and other circuits, and in software, can be realized by a program loaded into memory. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware alone, software alone, or a combination thereof, and are not limited to any one of them. In addition, the same elements are given the same symbols in each drawing, and duplicated explanations are omitted as necessary.

[0012] Moreover, the above-mentioned program includes a set of instructions (or software code) for making the computer perform one or more functions described in the embodiment when the program is read into the computer. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or the tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray (registered trademark) disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, the transitory computer-readable medium or the communication medium includes electrical, optical, acoustic, or other forms of propagating signals.

[0013] First embodiment FIG. 1 shows a schematic diagram of a battery unit according to the first embodiment. As shown in FIG. 1, the battery unit according to the first embodiment includes a temperature detection device 10 and a battery module 20. The battery module 20 has a plurality of battery cells 21 stacked in one direction, and is constrained so that a compressive force is maintained from both ends of the battery cells 21 in the stacking direction. Temperature sensors 31-33 are attached near both ends of the battery module 20 and near the center between both ends. The temperature sensors 31-33 are, for example, thermistors whose resistance value changes depending on the temperature of the attached battery cells.

[0014] The temperature detection device 10 obtains the resistance value change of the temperature sensors 31 to 33 as a temperature voltage, calculates the cell temperature from the temperature voltage, and notifies the upper system of the cell temperature. The temperature detection device 10 will be described in more detail. FIG. 2 shows a block diagram of the temperature detection device 10 according to the first embodiment.

[0015] As shown in FIG. 2, the temperature detection device 10 has n sensor connection terminals TM1 to TMn (n is an integer indicating the number of sensor connection terminals). The temperature detection device 10 also has pull-up resistors R1 to Rn corresponding to the sensor connection terminals TM1 to TMn. In the example shown in FIG. 2, temperature sensors 31 to 33 are connected to the sensor connection terminals TM1 to TM3 among the sensor connection terminals TM1 to TMn, and the sensor connection terminals TM4 to Tn are in an unconnected state in which no temperature sensor is connected. As a result, the sensor connection terminals TM1 to TM3 generate temperature voltages VL1 to VL3 obtained by dividing the power supply voltage VCC according to the resistance ratio between the resistance value of the temperature sensor and the pull-up resistor. The unconnected sensor terminals TM4 to TMn are supplied with the power supply voltage VCC via the pull-up resistors, and the temperature voltages VL4 to VLn become the power supply voltage VCC.

[0016] The temperature detection device 10 also has, as processing blocks, a voltage detection circuit 41, a voltage-temperature conversion circuit 42, and a fault detection circuit 43. The voltage detection circuit 41 cyclically converts the temperature voltages VL1 to VLn into digital values ​​at a predetermined cycle to calculate a voltage detection value AD[i]. i is the number of the sensor connection terminal at which the temperature voltage converted by the voltage detection circuit 41 is generated, and takes on values ​​from 1 to n. Then, the voltage-temperature conversion circuit 42 converts the voltage detection value AD[i] into a measurement value (for example, a temperature detection value T[i]) having a temperature value corresponding to the voltage detection value AD[i].

[0017] The fault detection circuit 43 performs fault detection for each sensor connection terminal using a determined value calculated by applying a terminal connection coefficient k to the temperature detection value T for each sensor connection terminal. Taking into account the result of the fault detection, the fault detection circuit 43 notifies the upper system of the temperature detection value T[i] and the sensor status information SC[i]. Note that this sensor status information also functions as an abnormality notification if it contains information indicating that an abnormality has occurred in the temperature sensor.

[0018] As described above, in the battery unit according to the first embodiment, fault detection is performed on the sensor connection terminals TM1 to TMn using the temperature detection value T[i] calculated by the voltage temperature conversion circuit 42. Also, in the battery unit according to the first embodiment, fault detection is performed by the fault detection circuit 43, thereby preventing the temperature detection value T[i] obtained from a faulty sensor connection terminal from being notified directly to a higher-level system. In the battery unit according to the first embodiment, one of the features is the fault detection circuit 43, so the fault detection circuit 43 will be described in more detail.

[0019] FIG. 3 shows a block diagram of the fault detection circuit 43 according to the first embodiment. As shown in FIG. 3, the fault detection circuit 43 includes a coefficient storage processing unit 51, a threshold value storage processing unit 52, a storage unit 53, a measurement value acquisition unit 54, a judged value calculation unit 55, and a fault detection unit 56. The fault detection circuit 43 can be implemented as a computer having a calculation unit capable of executing a program, for example. The processing performed in the blocks other than the storage unit 53 can be realized by a fault detection program executed in the calculation unit. Specifically, the fault detection program performs a coefficient storage process performed by the coefficient storage processing unit 51, a threshold value storage process performed by the threshold value storage processing unit 52, a measurement value acquisition process performed by the measurement value acquisition unit 54, a judged value calculation process performed by the judged value calculation unit 55, and a fault detection process performed by the fault detection unit 56.

[0020] The coefficient storage processing unit 51 is provided with terminal connection information provided from an operator or a production system externally during, for example, a shipping inspection of the battery unit. This terminal connection information indicates to which sensor connection terminal of the temperature detection device 10 the temperature sensor is connected. Then, based on the terminal connection information, the coefficient storage processing unit 51 stores in the storage unit 53 a terminal connection coefficient k[i] that is a first value (e.g., 1) when the temperature sensor is connected to the sensor connection terminal and a second value (e.g., 2) when the temperature sensor is not connected.

[0021] The threshold value storage processing unit 52 is provided with threshold value range information provided from an operator or a production system from the outside at the time of shipment inspection of the battery unit, for example. This threshold value range information includes an upper limit threshold and a lower limit threshold for determining an upper limit value and a lower limit value of the battery temperature. In the threshold value storage processing unit 52 according to the first embodiment, the upper limit threshold included in the threshold value range information is set as a first upper limit threshold UL1, and the lower limit threshold is set as a first lower limit threshold LL1. Then, the threshold value storage processing unit 52 stores in the storage unit 53 the first upper limit threshold UL1 and the first lower limit threshold LL1 that are set in advance, and the second upper limit threshold UL2 and the second lower limit threshold LL2 that are obtained by multiplying the first upper limit threshold UL1 and the first lower limit threshold LL1 by a second value (for example, 2). Note that the threshold value range is a normal range that is defined across negative values ​​to positive values, and the first upper limit threshold UL1 is a positive value, and the second lower limit threshold LL1 is a negative value.

[0022] Here, the thresholds applied in the fault detection circuit 43 according to the first embodiment will be described in detail. Fig. 4 shows a diagram for explaining the fault determination range in the fault detection circuit according to the first embodiment. In the following description, a fault detection circuit that determines the quality of a sensor connection terminal only based on a lower limit threshold LL corresponding to the first lower limit threshold LL1 of the fault detection circuit 43 and an upper limit threshold UP corresponding to the first upper limit threshold UL1 will be described as a comparative example.

[0023] In FIG. 4, a table explaining the fault judgment range in the comparative example is shown at the top of the drawing, and the fault judgment range according to the first embodiment is shown at the bottom of the drawing. As shown in FIG. 4, in the fault judgment range in the comparative example, when the sensor connection state indicates "connected", the temperature detection value T[i] is judged to be normal when it is in a range equal to or greater than the lower threshold LL and equal to or less than the upper threshold UL, and is judged to be abnormal when it is smaller than the lower threshold LL or larger than the upper threshold UL. Also, when the sensor connection state indicates "not connected" in the judgment range in the comparative example, the measured value T[i] does not indicate a range equal to or greater than the lower threshold LL and equal to or less than the upper threshold UL. On the other hand, when the sensor connection state indicates "not connected" in the judgment range in the comparative example, the temperature detection value T[i] is judged to be normal when it is smaller than the lower threshold LL, and is judged to be abnormal when it is larger than the upper threshold UL.

[0024] 4, in the fault determination range in the first embodiment, when the sensor connection state is "connected", the determination range is the same as that of the fault determination in the comparative example. On the other hand, when the sensor connection state is "disconnected", when the temperature detection value T[i] is smaller than the second lower threshold LL2 obtained by doubling the first lower threshold LL1, the temperature detection value is determined to be normal, and when the temperature detection value T[i] is larger than the second upper threshold UL2 obtained by doubling the first upper threshold UL1, the temperature detection value is determined to be abnormal.

[0025] In the fault detection circuit 43 according to the first embodiment, by making a pass / fail judgment of the sensor connection terminal using four threshold values ​​by utilizing the fact that the voltage at the unconnected sensor connection terminal is almost the same as the power supply voltage or the ground voltage, it is possible to identify the cause of the connection / non-connection and abnormality of the sensor connection terminal, whether it is due to a short circuit or a break, by a simple calculation. This judgment is made by the fault detection unit 56 described later.

[0026] The measurement value acquiring unit 54 acquires a measurement value (e.g., a temperature detection value T[i]) obtained from each of a plurality of sensor connection terminals (e.g., sensor connection terminals TM1 to TMn) provided for connecting a temperature sensor. The judged value calculating unit 55 calculates a judged value M[i] for each sensor connection terminal by multiplying the measurement value (e.g., the temperature detection value T[i]) by a terminal connection coefficient k[i].

[0027] The fault detection unit 56 performs fault determination for each sensor connection terminal based on the magnitude relationship between the judged value M[i] for each sensor connection terminal and the first upper threshold UL1, the first lower threshold LL1, the second upper threshold UL2, and the second lower threshold LL2. This fault determination process will be described in detail using a flowchart. FIG. 5 shows a flowchart for explaining the operation of the fault detection circuit according to the first embodiment. Note that FIG. 5 shows the process performed by the judged value calculation unit 55 and the fault detection unit 56 after the measured value acquisition unit 54 acquires the temperature detection value T. In addition, in the battery unit according to the first embodiment, the process shown in FIG. 5 is periodically performed for all sensor connection terminals.

[0028] As shown in FIG. 5, in the fault detection circuit 43, first, a variable i that specifies a sensor connection terminal is initialized to 1 (step S11). After that, in the fault detection circuit 43, the judged value calculation unit 55 multiplies the temperature detection value T[i] by the terminal connection coefficient k[i] to calculate the judged value M[i] (step S12). Note that the terminal connection coefficient k[i] that corresponds to a sensor connection terminal to which a temperature sensor is connected is a first value (e.g., 1), and that corresponds to a sensor connection terminal to which a temperature sensor is not connected is a second value (e.g., 2). After that, in the fault detection circuit 43, the fault detection unit 56 performs fault detection processing of the sensor connection terminal based on the judged value M[i]. The fault detection unit 56 performs fault detection processing by the following processing.

[0029] The fault detection unit 56 first performs a first determination process to check whether the reference value M[i] is within a normal range that is equal to or greater than the first lower limit threshold LL1 and equal to or less than the first upper limit threshold UL1 (step S13). In this first determination process, if the reference value M[i] is within the normal range, the fault detection unit 56 sets a value indicating that the temperature sensor is connected to the sensor connection terminal TMi and that the temperature sensor is operating normally in the sensor connection state value SC[i] and notifies the upper system (step S14). In addition, the fault detection unit 56 assigns the reference value M[i] to the temperature detection value T[i] and notifies the upper system (step S15).

[0030] Furthermore, when the judged value M[i] is out of the normal range, the fault detection unit 56 performs a second judgment process to judge whether the judged value M[i] is smaller than the second lower threshold LL2 (step S16). In the second judgment process, when the judged value M[i] is smaller than the second lower threshold LL2, the fault detection unit 56 puts a value indicating that the temperature sensor is not connected to the sensor connection terminal TM[i] and that the temperature sensor is operating normally into the sensor connection status value SC[i] and notifies the upper system (step S17). Furthermore, the fault detection unit 56 puts a value indicating that the sensor connection terminal TMi is an unconnected terminal (for example, NC) into the temperature detection value T[i] and notifies the upper system (step S18).

[0031] If it is determined in step S16 that the judged value M[i] is not in a range smaller than the second lower threshold LL2, the fault detection unit 56 performs a third judgment process to judge whether the judged value M[i] is equal to or larger than the second lower threshold LL2 and smaller than the first lower threshold LL1 (step S19). In the third judgment process, if the judged value M[i] is equal to or larger than the second lower threshold LL2 and smaller than the first lower threshold LL1, the fault detection unit 56 notifies the upper system by putting a value indicating that the temperature sensor is connected to the sensor connection terminal TM[i] and that a break has occurred in the path from the temperature sensor to the voltage detection circuit 41 into the sensor connection state value SC[i] (step S20). The sensor connection state value SC[i] generated in step S20 is a replacement instruction to the upper system. Furthermore, the fault detection unit 56 substitutes a substitute value into the temperature detection value T[i] and notifies the upper system (step S21). This substitute value can be, for example, the temperature detection value T[i] obtained from the sensor connection terminal TMi in the pre-processing cycle.

[0032] If it is determined in step S19 that the reference value M[i] is not in the range of not less than the second lower threshold LL2 and not less than the first lower threshold LL1, the failure detection unit 56 performs a fourth determination process to determine whether the reference value M[i] is greater than the first upper threshold UL1 and not more than the second upper threshold UL2 (step S22). In the fourth determination process, if the reference value M[i] is greater than the first upper threshold UL1 and is in the range of not more than the second upper threshold UL2, the failure detection unit 56 notifies the upper system by putting a value indicating that the temperature sensor is connected to the sensor connection terminal TM[i] and that a short circuit has occurred in the path from the temperature sensor to the voltage detection circuit 41 into the sensor connection state value SC[i] (step S23). The sensor connection state value SC[i] generated in step S23 serves as a replacement instruction to the upper system. The fault detection unit 56 also assigns a substitute value to the temperature detection value T[i] and notifies the host system (step S24). For example, the temperature detection value T[i] obtained from the sensor connection terminal TMi in the pre-processing cycle can be used as the substitute value.

[0033] Furthermore, when it is determined in step S19 that the reference value M[i] is greater than the first upper limit threshold UL1 and is not within the range equal to or less than the second upper limit threshold UL2, the failure detection unit 56 performs a fifth determination process in which the reference value M[i] is equal to or greater than the second upper limit threshold UL2. In the fifth determination process, the failure detection unit 56 notifies the upper system by putting a value indicating that the sensor connection terminal TMi is not connected and that a short circuit has occurred in the sensor connection state value SC[i] (step S25). The sensor connection state value SC[i] generated in step S25 is a replacement instruction to the upper system. Furthermore, the failure detection unit 56 assigns a value indicating that the sensor connection terminal TMi is an unconnected terminal (for example, NC) to the temperature detection value T[i] and notifies the upper system (step S26).

[0034] Then, when the processes of steps S15, S18, S21, S24, and S26 are completed, the failure detection circuit 43 increments the variable i by 1 and repeats the processes of steps S12 to S27 until the variable i exceeds n (steps S27 and S28).

[0035] Here, the flow of fault detection in a fault detection method according to a comparative example (when only one set of upper and lower thresholds is used) will be described. This comparative example was devised by the inventor to explain that the number of calculations is reduced in the processing of the fault detection circuit 43 according to the first embodiment. Therefore, a flowchart for explaining the operation of the fault detection circuit according to the comparative example is shown in FIG. 6.

[0036] 6, in the fault detection method according to the comparative example, first, a variable i is initialized to 1 (step S111). Next, in the fault detection method according to the comparative example, the temperature detection value T[i] is substituted for the judged value M[i] (step S112).

[0037] Then, in the fault detection method according to the comparative example, a first determination process is performed to check whether the reference value M[i] is within a normal range that is equal to or greater than the lower threshold LL and equal to or less than the upper threshold UL (step S113). In this first determination process, if the reference value M[i] is within the normal range, a value indicating that the temperature sensor is connected to the sensor connection terminal TMi and that the temperature sensor is operating normally is entered into the sensor connection status value SC[i], and the result is notified to the upper system (step S114). Also, in the fault detection method according to the comparative example, the reference value M[i] is substituted for the temperature detection value T[i], and the result is notified to the upper system (step S115).

[0038] On the other hand, when the judged value M[i] is out of the normal range, the fault detection method according to the comparative example judges whether the terminal connection state is a connected state based on a preset setting (step S116). If the connection state value CC[i] of the sensor connection terminal TMi corresponding to the judged value M[i] being processed is in the connected state, the processes of steps S117 to S121 are performed, and if the terminal connection state value CC[i] is in the unconnected state, the processes of steps S122 to S126 are performed.

[0039] The processing of steps S117 to S121 will be described. First, in step S117, it is determined whether the judged value M[i] is smaller than the lower threshold LL. Then, if it is determined in step S117 that the judged value M[i] is smaller than the lower threshold LL, a value indicating that the temperature sensor is connected to the sensor connection terminal TM[i] and that a break has occurred in the path from the temperature sensor to the voltage detection circuit 41 is entered into the sensor connection status value SC[i] and notified to the upper system (step S118). Also, in the fault detection method according to the comparative example, a substitute value is substituted for the temperature detection value T[i] and notified to the upper system (step S119). For example, the temperature detection value T[i] obtained from the sensor connection terminal TMi in the pre-processing cycle can be used as this substitute value.

[0040] On the other hand, if it is determined in step S117 that the judged value M[i] is greater than the lower limit threshold LL, a value indicating that the temperature sensor is connected to the sensor connection terminal TM[i] and that a short circuit has occurred in the path from the temperature sensor to the voltage detection circuit 41 is entered into the sensor connection state value SC[i] and notified to the upper system (step S120). In addition, the fault detection unit 56 assigns a substitute value to the temperature detection value T[i] and notifies the upper system (step S121). For example, the temperature detection value T[i] obtained from the sensor connection terminal TMi in the pre-processing cycle can be used as this substitute value.

[0041] Next, the processing of steps S122 to S126 will be described. In step S122, it is determined whether the judged value M[i] is smaller than the lower threshold LL. Then, if it is determined in step S122 that the judged value M[i] is smaller than the lower threshold LL, a value indicating that the sensor connection terminal TM[i] is in an unconnected state and is in a normal state without any fault such as a short circuit is entered into the sensor connection state value SC[i], and notified to the upper system (step S123). Also, in the fault detection method according to the comparative example, a value indicating that the sensor connection terminal TMi is an unconnected terminal (for example, NC) is substituted into the temperature detection value T[i], and notified to the upper system (step S124).

[0042] On the other hand, if it is determined in step S122 that the judged value M[i] is greater than the lower limit threshold LL, the sensor connection state value SC[i] is set to a value indicating that the sensor connection terminal TM[i] is in an unconnected state and that a short circuit has occurred in the sensor connection terminal TMi, and notifies the upper system (step S125). Also, the fault detection unit 56 assigns a value indicating that the sensor connection terminal TMi is an unconnected terminal (for example, NC) to the temperature detection value T[i], and notifies the upper system (step S126).

[0043] Then, in the fault detection method according to the comparative example, when the processes of steps S115, S119, S121, S124, and S126 are completed, the variable i is incremented by 1, and the processes of steps S112 to S127 are repeated until the variable i exceeds n (steps S127 and S128).

[0044] Here, the difference in the number of calculations between the fault detection circuit 43 according to the first embodiment and the fault detection method according to the comparative example will be described. Here, the explanation will be given by focusing in particular on the number of branch processes in the flowcharts of Figures 5 and 6. Figure 7 shows a diagram for explaining the difference in the number of branch processes between the comparative example and the first embodiment.

[0045] 7, when the temperature sensor is connected to the sensor connection terminal and the determination result is normal, the number of branch processes in both the fault detection circuit 43 according to the first embodiment and the fault detection method according to the comparative example is one. On the other hand, when the sensor connection terminal is not connected and the determination result is normal, the number of branch processes in the fault detection circuit 43 according to the first embodiment is one less than the number of branch processes in the fault detection method according to the comparative example. Also, when the determination result indicates an abnormal state, the number of branch processes in the fault detection circuit 43 according to the first embodiment is the same as the number of branch processes in the fault detection method according to the comparative example or one more.

[0046] As described above, in the fault detection circuit 43 according to the first embodiment, the presence or absence of a fault occurring in relation to the sensor connection terminal TMi can be determined only by the measurement value obtained from the sensor connection terminal TMi. Furthermore, in the fault detection circuit 43, the presence or absence of a fault can be determined only by the multiplication used in generating the judged value M[i] and the comparison of the judged value M[i] with the four threshold values. As a result, in the fault detection circuit 43 according to the first embodiment, the processing related to the fault determination can be reduced.

[0047] In addition, in the fault detection circuit 43 according to the fourth embodiment, the measured value T[i] obtained from the sensor connection terminal TMi to which the temperature sensor is not connected is shifted by the terminal connection coefficient k, and four thresholds are provided, so that the number of branching processes in which the processing content changes can be reduced as described in FIG. 7. Specifically, fault detection by the fault detection circuit 43 is repeatedly performed during the period in which the battery unit is in use and the judgment result is judged to be normal, and when a fault is found, a replacement instruction is notified to the upper system, and the usage state moves toward termination. Therefore, in the battery unit, the number of calculations in the normal state has a large effect on the power consumption. For this reason, the effect obtained by reducing the number of calculations in the normal state as in the fault detection circuit 43 is large. On the other hand, in the fault detection circuit 43, the number of calculations when a fault occurs increases compared to the comparative example, but after the fault state occurs, the number of times the fault detection circuit 43 detects a fault is extremely small compared to the normal state, so the effect on the power consumption is small.

[0048] In order to reduce the number of branching processes, it is preferable that the third to fifth determination processes (steps S19 to S26) are performed after the first and second determination processes (steps S13 to S18).

[0049] Furthermore, in the fault detection circuit 43 according to the first embodiment, the temperature detection value T[i] obtained in the pre-processing cycle that is determined to be normal is used as the temperature detection value T[i] to be notified to the upper system when a fault occurs. In this way, by notifying the upper system of the normal value obtained immediately before instead of the temperature detection value T[i] when an abnormal state is detected, it is possible to prevent the upper system from controlling the battery unit based on the abnormal value.

[0050] In the above description, a temperature sensor is used as the sensor, but the failure detection circuit 43 can also be applied to measurement values ​​obtained from sensors other than a temperature sensor.

[0051] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0052] 10 Temperature detection device 20 Battery Module 21 Battery Cell 31~33 Temperature sensor 41 Voltage detection circuit 42 Voltage temperature conversion circuit 43 Fault detection circuit 51 Coefficient storage processing unit 52 Threshold storage processing unit 53 Storage section 54 Measurement value acquisition section 55 Judgment value calculation unit 56 Fault detection section

Claims

1. A fault detection program executed by a calculation unit, in a temperature detection device having a plurality of sensor connection terminals provided for connecting sensors, for detecting faults related to disconnections and short circuits in a signal path occurring in association with the sensor connection terminals, the program comprising: a coefficient storage process for storing, in a storage unit, a terminal connection coefficient that is a first value when the sensor is connected to each of the sensor connection terminals and a second value when the sensor is not connected; a threshold value storing process for storing in the storage unit a first upper limit threshold and a first lower limit threshold that are set in advance, and a second upper limit threshold and a second lower limit threshold that are obtained by multiplying the first upper limit threshold and the first lower limit threshold by the second value; a measurement value acquisition process for acquiring a measurement value obtained from each of the sensor connection terminals; a determined value calculation process for calculating a determined value for each of the sensor connection terminals by multiplying the measurement value by the terminal connection coefficient; A fault detection program that performs fault detection processing to determine a fault for each of the sensor connection terminals based on the magnitude relationship between the determined value and the first upper limit threshold, the first lower limit threshold, the second upper limit threshold, and the second lower limit threshold for each of the sensor connection terminals.

2. In the failure detection process, a first determination process for determining, when the determined value is between the first upper limit threshold and the first lower limit threshold, that the sensor is connected to the sensor connection terminal and that there is no path failure, that is, a normal state; a second determination process for determining, when the determined value is smaller than the second lower limit threshold, that the sensor is not connected to the sensor connection terminal and that there is no path failure, that is, a normal state; a third determination process for determining, when the determined value is equal to or greater than the second lower threshold and less than the first lower threshold, that the sensor is connected to the sensor connection terminal and that a disconnection fault exists in a path, thereby determining that the state is an abnormal disconnection state; a fourth determination process for determining, when the determined value is greater than the first upper limit threshold and is equal to or less than the second upper limit threshold, that the sensor is connected to the sensor connection terminal and that a short circuit abnormality exists in a path; a fifth determination process for determining, when the determined value is greater than the second upper limit threshold, that the sensor is not connected to the sensor connection terminal and that a short circuit abnormality exists in a path; and 2. The fault detection program according to claim 1, wherein the fault detection program further comprises:

3. 3. The fault detection program according to claim 2, wherein the third to fifth determination processes are performed after the first and second determination processes.

4. 4. The fault detection program according to claim 2, further comprising: a notification of an abnormality being sent to a host system after the third determination process, the fourth determination process, and the fifth determination process.

5. 5. The fault detection program according to claim 2, further comprising: notifying a host system of the measurement value acquired in a pre-processing cycle as a substitute value for the measurement value after the third judgment process and the fourth judgment process.

6. 6. The fault detection program according to claim 1, wherein the first upper limit threshold is a positive value, and the second lower limit threshold is a negative value.

7. 7. The fault detection program according to claim 1, wherein the sensor is a temperature sensor, and the measured value is a value indicating a temperature.

8. a measurement value acquiring unit that acquires measurement values ​​obtained from a plurality of sensor connection terminals provided for connecting sensors for each of the sensor connection terminals; a coefficient storage processing unit that stores in a storage unit a terminal connection coefficient that has a first value when the sensor is connected to the sensor connection terminal and a second value when the sensor is not connected to the sensor connection terminal; a threshold value saving processing unit that saves in the storage unit a first upper limit threshold and a first lower limit threshold that are set in advance, and a second upper limit threshold and a second lower limit threshold that are obtained by multiplying the first upper limit threshold and the first lower limit threshold by the second value; a determined value calculation unit that calculates a determined value for each of the sensor connection terminals by multiplying the measurement value by the terminal connection coefficient; A fault detection circuit that performs fault detection for each of the sensor connection terminals based on the magnitude relationship between the determined value and the first upper limit threshold, the first lower limit threshold, the second upper limit threshold, and the second lower limit threshold.

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