Disconnection detection program, disconnection detection method, and disconnection detection device

Abstract

To solve a problem that the efficiency of detecting a break of a detection line for detecting battery voltage has been low.SOLUTION: A cable break detection program according to the present invention is a cable break detection program executed by an arithmetic unit in a battery voltage detection device that detects the voltage of each of k battery cells connected in series, where k is an integer, by means of k+1 detection lines connected to each electrode of k+1 battery cells. The program includes a threshold reading process S2 for reading a cable break threshold from a cable-break threshold register, a dummy detection voltage reading process S3, in which a dummy detection voltage is read from a dummy detection voltage register saved as the 0th detection voltage and the k+1th detection voltage, a detection voltage acquisition process S4, which acquires the voltage detected from the battery cell as the detection voltage, and a cable break detection process S5, which detects the presence or absence of a disconnection of the first to k+1th detection line by applying the detection voltage and cable-disconnection threshold of the 0th to k+1th detection line to a cable break determination formula commonly set for one or more k.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a disconnection detection program, a disconnection detection method, and a disconnection detection device for detecting a disconnection in wiring connecting a battery voltage measurement device that measures the battery voltage of each of a plurality of battery cells connected in series with an electrode of a battery cell in a battery system having a plurality of switches that switch the conduction state between the battery voltage measurement device and the electrode of the battery cell. [Background technology]

[0002] In an assembled battery in which multiple battery cells are combined and used as a single battery, the battery voltage of each of the multiple battery cells connected in series is measured. Patent Document 1 discloses an example of a technique for measuring the battery voltage in an assembled battery.

[0003] The flying capacitor type voltage measuring device described in Patent Document 1 is a flying capacitor type voltage measuring device that includes a capacitor, a first multiplexer, a second multiplexer, a voltage measuring means, a sample voltage measuring switch, a control means, voltage detection terminals that are respectively connected to both ends of each voltage source and a pair of resistors connected between the multiplexer, and a plurality of filters each consisting of a capacitor connected between the connection points of the resistors and the multiplexer, in which the resistance value of one resistor of the pair of resistors connected to the first and (N+1)-th voltage detection terminals of the (N+1) voltage detection terminals is set to be smaller than the resistance value of the other resistor of the pair of resistors, and the total resistance value of the pair of resistors is set to be equal in all of the plurality of filters. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-240299 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, in order to measure the battery voltage of the battery cell, a wire break detection process is performed on the detection wire to check the normality of the detection wire connected to each electrode. Patent Document 1 does not disclose or suggest the wire break detection process, and there is a problem that it is difficult to efficiently perform wire break detection.

[0006] The present invention has been made in view of the above circumstances, and has as its object to efficiently detect breaks in detection lines. [Means for solving the problem]

[0007] One aspect of the open circuit detection program of the present invention is a program executed by a calculation unit in a battery voltage detection device that detects the voltages of k battery cells connected in series, where k is an integer, using k+1 detection lines connected to each electrode of the k+1 battery cells, and that detects open circuits in the detection lines in the battery voltage detection device. The program performs the following operations: a threshold reading process that reads an open circuit threshold for determining whether the detection line has been opened from an open circuit threshold register; a dummy detection voltage reading process that reads a dummy detection voltage from a dummy detection voltage register in which a dummy detection voltage is saved as the 0th detection voltage and the k+1th detection voltage; a detection voltage acquisition process that acquires the voltages detected from the battery cells as the 1st detection voltage to the nth detection voltage, starting from the battery cell located on the high potential side; and an open circuit detection process that applies the 0th to the k+1th detection voltages and the open circuit threshold to an open circuit determination formula set commonly for k, which is 1 or greater, to detect whether the 1st to the k+1th detection lines have been opened.

[0008] One aspect of the open circuit detection method of the present invention is a battery voltage detection device that detects the voltages of k battery cells connected in series, where k is an integer, using k+1 detection lines connected to each electrode of the k+1 battery cells, and detects open circuits in the detection lines through calculations performed in the device. The method includes a threshold reading process that reads an open circuit threshold for determining whether the detection line is open from an open circuit threshold register, a dummy detection voltage reading process that reads a dummy detection voltage from a dummy detection voltage register in which the dummy detection voltage is saved as the 0th detection voltage and the k+1th detection voltage, a detection voltage acquisition process that acquires the voltages detected from the battery cells as the 1st detection voltage to the nth detection voltage, starting from the battery cell located on the high potential side, and a open circuit detection process that applies the 0th to the k+1th detection voltages and the open circuit threshold to an open circuit determination formula set commonly for k, which is 1 or greater, to detect whether the 1st to the k+1th detection lines are open.

[0009] One aspect of the wire break detection device of the present invention is a wire break detection device that detects wire breaks in k+1 detection lines connected to k+1 electrodes of k battery cells connected in series, where k is an integer, and includes: a wire break threshold register that stores a wire break threshold for determining whether the detection lines are broken; a dummy detection voltage register that stores dummy detection voltages as the 0th detection voltage and the k+1th detection voltage; a detection voltage acquisition unit that acquires the voltages detected from the battery cells as the 1st detection voltage to the nth detection voltage, in order from the battery cells arranged on the high potential side; and a wire break detection unit that applies the 0th to the k+1th detection voltages and the wire break threshold to a wire break determination equation set commonly for k equal to or greater than 1, to detect whether the 1st to the k+1th detection lines are broken. [Effects of the Invention]

[0010] According to the program, method, and device for detecting a break in the detection line of the present invention, it is possible to efficiently detect a break in the detection line. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a block diagram of a battery unit according to a first embodiment. [Figure 2] 2 is a table illustrating switch states in a disconnection detection process in the battery unit shown in FIG. 1. [Figure 3] 2 is a block diagram showing a battery unit according to the first embodiment in which the number of battery cells is one. FIG. [Figure 4] 4 is a table illustrating switch states in a disconnection detection process in the battery unit shown in FIG. 3. [Figure 5] 1 is a block diagram of a disconnection detection device according to a first embodiment. [Figure 6] 4 is a flowchart illustrating an operation of the disconnection detection device according to the first embodiment. [Figure 7] FIG. 10 is a block diagram of a battery unit according to a second embodiment. [Figure 8] 8 is a table illustrating switch states in a disconnection detection process in the battery unit shown in FIG. 7. [Figure 9] FIG. 10 is a block diagram of a battery unit according to a second embodiment, in which the number of battery cells is one. [Figure 10] 10 is a table illustrating switch states in the disconnection detection process in the battery unit shown in FIG. 9. [Figure 11] FIG. 10 is a block diagram of a disconnection detection device according to a second embodiment. [Figure 12] 10 is a flowchart illustrating the operation of the disconnection detection device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. Furthermore, 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 with a program loaded into memory, etc. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms using only hardware, only software, or a combination thereof, and are not limited to any one of these. In addition, the same elements are designated by the same reference numerals in each drawing, and redundant explanations are omitted as necessary.

[0013] Furthermore, the above-described program includes a set of instructions (or software code) that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include 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) disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0014] Embodiment 1 FIG. 1 shows a block diagram of a battery unit 1 according to the first embodiment. As shown in FIG. 1, the battery unit 1 according to the first embodiment includes a battery pack, a switch unit 11, a detection voltage generation circuit 12, and a disconnection detection device 13. Although FIG. 1 shows a battery pack having a plurality of battery cells B1 to B6 connected in series, the number of batteries in the battery pack is not limited to six. Furthermore, although FIG. 1 omits a description of the voltage detection process of the voltage detection device that detects the individual voltages of the battery cells B1 to B6, the switch unit 11, detection voltage generation circuit 12, and disconnection detection device 13 constitute part of the voltage detection device.

[0015] In the description of the battery unit 1 according to the first embodiment, k is used to represent the number of battery cells connected in series, and i is used to represent the order of the battery cells. In the example shown in FIG. 1, k=6, and i is a variable between 1 and k. In addition, in the example shown in FIG. 1, there are k+3 detection lines for six battery cells, ranging from the 0th detection line to the k+2nd detection line. The numbers of the battery cells, detection lines, etc. are assigned in descending order, starting with the one corresponding to the highest potential.

[0016] Switch unit 11 selects a battery from which to acquire detected voltage. Switch unit 11 has switches SW10 to SW18. Although wiring for transmitting control signals is not shown, the open / closed states of switches SW10 to SW18 are controlled by, for example, disconnection detection device 13.

[0017] The switch SW10 has one end connected to the 0th detection line W0 connected to the node between the negative electrode of the battery cell B1 and the positive electrode of the battery cell B2, and the other end connected to node N2. The switch SW11 has one end connected to the 1st detection line W1 connected to the positive electrode of the battery cell B1, and the other end connected to node N1. The switch SW12 has one end connected to the 2nd detection line W2 connected to the node between the negative electrode of the battery cell B1 and the positive electrode of the battery cell B2, and the other end connected to node N2. Here, the switches SW10 and SW12 are connected in parallel.

[0018] The switch SW13 has one end connected to the third detection line W3 connected to the node between the negative electrode of the battery cell B2 and the positive electrode of the battery cell B3, and the other end connected to node N1. The switch SW14 has one end connected to the fourth detection line W4 connected to the node between the negative electrode of the battery cell B3 and the positive electrode of the battery cell B4, and the other end connected to node N2. The switch SW15 has one end connected to the fifth detection line W5 connected to the node between the negative electrode of the battery cell B4 and the positive electrode of the battery cell B5, and the other end connected to node N1. The switch SW16 has one end connected to the sixth detection line W6 connected to the node between the negative electrode of the battery cell B5 and the positive electrode of the battery cell B6, and the other end connected to node N2. The switch SW17 has one end connected to the seventh detection line W7 connected to the negative electrode of the battery cell B7, and the other end connected to node N1. One end of switch SW18 is connected to the eighth detection line W8, which is connected to the node between the negative electrode of battery cell B5 and the positive electrode of battery cell B6, and the other end is connected to node N2. Here, switches SW16 and SW18 are connected in parallel.

[0019] The detection voltage generation circuit 12 outputs, as a detection voltage, the absolute value of the difference between the voltage Vn1 transmitted to the node N1 and the voltage Vn2 transmitted to the node N2. As shown in Fig. 1, the detection voltage generation circuit 12 includes switches SW21, SW22, SW31 to SW34, a capacitor C1, resistors Rb, R11 to R13, and R21 to R23, and operational amplifiers OP1 and OP2. Although wiring for transmitting control signals is not shown, the open / closed states of the switches SW21, SW22, and SW31 to SW34 are controlled by, for example, a disconnection detection device 13.

[0020] The switch SW21 has one end connected to the node N1. The switch SW22 has one end connected to the node N2. The switches SW31 and SW33 have one ends connected to the other end of the switch SW21. The switches SW32 and SW34 have one ends connected to the other end of the switch SW22. The capacitor C1 is provided between the other end of the switch SW21 and the other end of the switch SW22.

[0021] The operational amplifier OP1 outputs the difference between the voltage Vn1 transmitted to the node N1 and the voltage Vn2 transmitted to the node N2 as a detection voltage. The resistor R11 is provided between the inverting terminal of the operational amplifier OP1 and the other end of the switch SW31. The resistor R12 is provided between the inverting terminal and the output terminal of the operational amplifier OP1. The resistor R13 is provided between the non-inverting terminal of the operational amplifier OP1 and the other end of the switch SW32. The resistor Rb is provided between the bias voltage terminal, the non-inverting terminal of the operational amplifier OP1, and the non-inverting terminal of the operational amplifier OP2.

[0022] The operational amplifier OP2 outputs the difference between the voltage Vn2 transmitted to the node N2 and the voltage Vn1 transmitted to the node N1 as a detection voltage. The resistor R21 is provided between the inverting terminal of the operational amplifier OP2 and the other end of the switch SW34. The resistor R22 is provided between the inverting terminal and the output terminal of the operational amplifier OP2. The resistor R23 is provided between the non-inverting terminal of the operational amplifier OP2 and the other end of the switch SW33.

[0023] The disconnection detection device 13 can be realized by, for example, an MPU (Micro Processor Unit) having multiple registers, a calculation unit capable of executing programs, and a communication interface with other devices (e.g., a higher-level system). The functions of the processing blocks described below can also be implemented as hardware in the disconnection detection device 13. The disconnection detection device 13 detects the presence or absence of a disconnection in the detection lines W1 to W7 by applying the detection voltages V[0] to V[7] and the disconnection threshold to a disconnection determination formula set in common for k, which is 1 or greater. More generally, the disconnection detection device 13 detects the presence or absence of a disconnection in the 1st to k+1th detection lines W1 to Wk+1 by applying the 0th to k+1th detection voltages V[0] to V[k+1] and the disconnection threshold to a disconnection determination formula set in common for k, which is 1 or greater.

[0024] Here, of the detected voltages, detected voltages V[1] to V[6] are the battery voltages of battery cells B1 to B6. Detected voltage V[0] is the battery voltage of battery cell B1 obtained when switches SW10 and SW11 are conductive, and is a dummy detected voltage. Detected voltage V[7] is the battery voltage of battery cell B6 obtained when switches SW18 and SW17 are conductive, and is a dummy detected voltage. In other words, of detected voltages V[0] to V[k+1], detected voltages V[0] and V[k+1] are acquired by open-circuit detection device 13 as dummy voltages.

[0025] Here, we will explain the switches that are turned on when obtaining the detection voltages V[0] to V[7] in the battery unit 1. Figure 2 shows a table explaining the switch states during the disconnection detection process in the battery unit 1 shown in Figure 1.

[0026] As shown in Fig. 2, in the battery unit 1 according to the first embodiment, when detecting voltages V[1] to V[6] of the battery cells B1 to B6, the switches connected to the detection lines connected to the positive and negative electrodes of the battery cells from which the detection voltages are to be obtained are turned on. At this time, switches SW31 to SW34 are switched based on the connection between the detection lines connected to each battery cell and the nodes N1 and N2 downstream of the detection lines, and the detection voltages of odd-numbered battery cells are obtained from the output value of operational amplifier OP1. Meanwhile, the detection voltages of even-numbered battery cells are obtained from the output value of operational amplifier OP2.

[0027] In the battery unit 1 according to the first embodiment, the battery voltage of the battery cell B1, which is positioned to have the highest potential as the dummy voltage, is acquired using a combination of switches SW10 and SW11 that is different from the combination of switches SW11 and SW12. This is used as the dummy detection voltage. In the battery unit 1 according to the first embodiment, the battery voltage of the battery cell B6, which is positioned to have the lowest potential as the dummy voltage, is acquired using a combination of switches SW17 and SW18 that is different from the combination of switches SW16 and SW17. When acquiring the detection voltage V[0], the switches SW31 and SW32 are set to a conductive state, and the output value of the operational amplifier OP1 is acquired. When acquiring the detection voltage V[7], the switches SW33 and SW34 are set to a conductive state, and the output value of the operational amplifier OP2 is acquired.

[0028] As described above, the disconnection detection device 13 can be applied if the number k of battery cells connected in series is 1 or greater. Therefore, a battery unit 1 when k is 1 will be described. FIG. 3 shows a block diagram of the battery unit according to the first embodiment when the number of battery cells is one.

[0029] The battery unit 1 according to the first embodiment shown in FIG. 3 is designed to test only the battery cell B1. The battery unit 1 according to the first embodiment shown in FIG. 3 also has a switch unit 11a instead of the switch unit 11 shown in FIG. 1. The switch unit 11a has switches SW10 to SW13. The switch SW11 is a switch corresponding to the detection line B1 connected to the positive electrode of the battery cell B1. The switch SW12 is a switch corresponding to the negative electrode of the battery cell B1. The switch SW10 is connected in parallel to the switch SW12. The switch SW13 is connected in parallel to the switch SW11.

[0030] 3 according to the first embodiment has a disconnection detection device 13a instead of the disconnection detection device 13 shown in FIG. The disconnection detection device 13a stores fewer detected voltages than the disconnection detection device 13, and stores detected voltages V[0] to V[2]. Here, the disconnection detection device 13a uses the detected voltages V[0] and V[2] as dummy detected voltages.

[0031] FIG. 4 shows a table illustrating the switch states during the disconnection detection process in the battery unit shown in FIG. 3. As shown in FIG. 4, in the battery unit 1 shown in FIG. 3, all detection voltages are acquired for battery cell B1. The dummy detection voltage V[0] is acquired from the output value of operational amplifier OP1 with switches SW10, SW11, SW31, and SW32 in a conductive state. The detection voltage V[1] is acquired from the output value of operational amplifier OP1 with switches SW11, SW12, SW31, and SW32 in a conductive state. The dummy detection voltage V[2] is acquired from the output value of operational amplifier OP1 with switches SW12, SW13, SW31, and SW32 in a conductive state.

[0032] In the battery unit 1 according to the first embodiment, two dummy detection voltages V[0] and V[k+1] are acquired regardless of the value of k, and these dummy detection voltages are used to detect a disconnection in the detection line Wi using a disconnection determination formula that is commonly used for all values ​​of k. In the battery unit 1, the disconnection detection device 13 performs a disconnection detection process using the disconnection determination formula. Here, the disconnection detection device 13 will be described in more detail.

[0033] 5 shows a block diagram of the disconnection detection device 13 according to the first embodiment. Although the disconnection detection device 13 can be implemented as dedicated hardware, the embodiment describes an example in which it is realized by an MPU (Micro Processor Unit) that has a calculation unit capable of executing programs and a communication interface with other devices (e.g., a higher-level system). In the description of the disconnection detection device 13, i is used to indicate the numbers of the battery cells, detection voltages, dummy detection voltages, and detection lines, generalizing these numbers, and k is used to indicate the total number of battery cells, detection voltages, dummy detection voltages, and detection lines.

[0034] 5, the disconnection detection device 13 includes a disconnection threshold value storage processing unit 21, a disconnection threshold value register 22, a detected voltage acquisition unit 23, a detected voltage register 25, and a disconnection detection unit 26. The detected voltage acquisition unit 23 includes a dummy detected voltage storage processing unit 24.

[0035] The disconnection threshold value saving processing unit 21 stores the disconnection threshold value provided from the upper system in the disconnection threshold value register 22. The disconnection threshold value register 22 holds the disconnection threshold value in the disconnection detection device 13. The disconnection threshold value is a value that is surely smaller than the detection voltage acquired in a normal state where there is no disconnection in the detection line Wi.

[0036] The detected voltage acquisition unit 23 acquires the voltages detected from the battery cells as the first detected voltage V[1] to the kth detected voltage V[k], in order from the battery cell located on the high potential side, and stores them in the detected voltage storage area of ​​the detected voltage register 25 (the area marked V[1] to V[k] in FIG. 5). The dummy detected voltage storage processing unit 24 stores the 0th detected voltage, which is the battery voltage of battery cell B1 obtained by a different switch combination than when the detected voltage V[1] was acquired, as the dummy detected voltage V[0] in the dummy detected voltage storage area of ​​the detected voltage register 25 (the area marked V[0] to V[k+1] in FIG. 5). The dummy detected voltage storage processing unit 24 also stores the k+1th detected voltage, which is the battery voltage of battery cell Bk obtained by a different switch combination than when the detected voltage V[k] was acquired, as the dummy detected voltage V[k+1] in the dummy detected voltage storage area of ​​the detected voltage register 25.

[0037] The disconnection detection unit 26 detects whether or not there is a disconnection in the 1st to k+1th detection lines by applying the 0th to k+1th detection voltages and disconnection thresholds to a disconnection determination formula set in common for k, which is equal to or greater than 1. Here, the disconnection determination formula used by the disconnection detection unit 26 is expressed by formula (1). i=1~k+1: V[i-1]<disconnection threshold and V[i]<disconnection threshold (1) The disconnection detection unit 26 notifies the host system of the presence or absence of the detected line, which is detected based on the formula (1).

[0038] Next, the operation of the disconnection detection device 13 will be described using a flowchart. Fig. 6 shows a flowchart explaining the operation of the disconnection detection device 13 according to the first embodiment. The disconnection detection device 13 repeatedly executes the disconnection detection process shown in Fig. 6 at a predetermined timing or period.

[0039] 6, when the disconnection detection device 13 starts the disconnection detection process, it first initializes i, which indicates the number of the detection line that is the target of disconnection detection, to 1 (step S1). Next, in the disconnection detection device 13, the disconnection detection unit 26 reads the disconnection threshold from the disconnection threshold register 22 (step S2). Furthermore, the disconnection detection device 13 causes the disconnection detection unit 26 to read the dummy detection voltages V[0] and V[k+1] stored in the detection voltage register 25 using the dummy detection voltage storage processing unit 24 (step S3). Furthermore, the disconnection detection device 13 causes the disconnection detection unit 26 to read the detection voltages V[1] to V[k] stored in the detection voltage register 25 using the detection voltage acquisition unit 23 (step S4).

[0040] Then, the disconnection detection unit 26 determines whether the voltage corresponding to i among the read dummy detection voltages and detection voltages satisfies the disconnection determination formula shown in Equation (1) (step S5). If the voltage under consideration satisfies the disconnection determination formula in step S5, the disconnection detection unit 26 notifies the upper system that a disconnection has occurred in the detection line Wi (step S6). On the other hand, if it is determined in step S5 that the voltage under consideration does not satisfy the disconnection determination formula, the disconnection detection unit 26 repeats the determination in step S5 while incrementing i by 1 until i becomes equal to or greater than k+1 (steps S7 and S8).

[0041] As explained above, the battery unit 1 including the wire break detection device 13 according to the first embodiment determines whether or not there is a break in the detection line Wi using a wire break determination formula that is commonly used for k equal to or greater than 1. In other words, by using the wire break detection device 13 according to the first embodiment, it is possible to determine whether or not there is a break in the detection line that should be detected for breakage by applying a common wire break detection program or wire break detection device regardless of the number of battery cells included in the battery pack to be inspected.

[0042] In this way, by applying a common disconnection detection program or disconnection detection device to battery packs configured according to a variety of specifications, it is possible to reduce the costs of verifying the program, managing parts, and designing.

[0043] Embodiment 2 In the second embodiment, a battery unit 2 will be described, which is another embodiment of the battery unit 1. In the description of the second embodiment, the same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0044] Fig. 7 shows a block diagram of a battery unit according to the second embodiment. As shown in Fig. 7, the battery unit 2 according to the second embodiment has a switch unit 31 and a disconnection detection device 33 instead of the switch unit 11 and the disconnection detection device 13 of the battery unit 1 according to the first embodiment. The switch unit 31 is obtained by removing the switches SW10 and SW18 from the switch unit 11. The disconnection detection device 33 uses fixed values ​​provided by a higher-level system or the like, rather than measured values, as the detection voltages V[0] and V[k+1] (for example, V[7]) used as dummy detection voltages.

[0045] Fig. 8 shows a table explaining the switch states in the disconnection detection process in the battery unit shown in Fig. 7. As shown in Fig. 8, the method of acquiring the detection voltages V[1] to V[6] in the battery unit 2 according to the second embodiment is the same as that of the battery unit 1 according to the first embodiment. On the other hand, in the second embodiment, the detection voltages V[0] and V[7] used as dummy detection voltages are set by calculation.

[0046] The detection voltages V[0] and V[7] used as the dummy detection voltages are calculated from the maximum and minimum values ​​of the detection voltages V[1] to V[6]. For example, the maximum value is set to the detection voltage V[0], and the minimum value is set to the detection voltage V[7]. In this way, by storing the maximum and minimum values ​​of the battery cells in the register that stores the dummy detection voltages, it is possible to reduce the memory capacity used in the battery unit 2. Also in the second embodiment, the detection voltage used as the dummy detection voltage is a value that is reliably greater than the determination threshold.

[0047] Here, the configuration when k is 1 will also be described in the second embodiment. FIG. 9 shows a block diagram of a battery unit according to the second embodiment when the number of battery cells is one. As shown in FIG. 9, when the number of battery cells to be measured is one, a switch unit 31a and a disconnection detection device 33a are used instead of the switch unit 31 and the disconnection detection device 33. The switch unit 31a is the switch unit 11a without the switches SW10 and SW13. The disconnection detection device 33a uses calculated values ​​as the detection voltages V[0] and V[2], which are dummy detection voltages of the disconnection detection device 13a.

[0048] 10 shows a table explaining the switch states in the disconnection detection process in the battery unit shown in Fig. 9. As shown in Fig. 10, the method of acquiring the detection voltage V[1] in the battery unit 2 according to the second embodiment is the same as that in the battery unit 1 according to the first embodiment. On the other hand, in the second embodiment, the detection voltages V[0] and V[2] used as dummy detection voltages are set by calculation.

[0049] Next, the disconnection detection device 33 will be described in detail. Fig. 11 shows a block diagram of the disconnection detection device according to the second embodiment. As shown in Fig. 11, the disconnection detection device 33 includes a disconnection threshold value saving processing unit 21, a disconnection threshold value register 22, a detection voltage acquisition unit 43, a detection voltage register 45, and a disconnection detection unit 46.

[0050] The disconnection threshold value saving processing unit 21 and the disconnection threshold value register 22 are the disconnection threshold value saving processing unit 21 and the disconnection threshold value register 22 of the disconnection detection device 13 according to the first embodiment. In the disconnection detection device 33 according to the second embodiment, the disconnection threshold value is updated by a higher-level system.

[0051] The detected voltage acquisition unit 43 acquires the voltages detected from the battery cells as the first detected voltage V[1] to the kth detected voltage V[k] in order from the battery cell arranged on the high potential side, and stores them in the detected voltage storage area (area marked V[1] to V[k] in FIG. 11) of the detected voltage register 45. In addition, the dummy detected voltage storage area (area marked V[0], V[k+1] in FIG. 11) of the detected voltage register 45 stores the detected voltages V[0], V[k+1] as dummy detected voltages calculated in the higher-level system.

[0052] The disconnection detection unit 46 detects whether or not a disconnection has occurred in the 1st to k+1th detection lines by applying the 0th to k+1th detection voltages and the disconnection threshold value to a disconnection determination formula set in common for k, which is equal to or greater than 1. Here, the disconnection determination formula used by the disconnection detection unit 46 is the formulas (2) to (4) in which the i-th detection voltage is expressed as V[i], and the disconnection detection unit 46 determines that a disconnection has occurred in the 1st to k+1th detection lines Wi that satisfy the formulas (2) to (4). i=1: V[i]<open circuit threshold and V[i+1]>open circuit threshold (2) i=2~k (only when k≧2): V[i-1]<disconnection threshold and V[i]<disconnection threshold (3) i=k+1: V[i-2]>break threshold and V[i-1]<break threshold (4) The disconnection detection unit 46 notifies the host system of the presence or absence of a detected line based on equations (2) to (4). The equation (3) is implemented when k is 2, 3, 4, and so on, and is equal to or greater than 2, but when k is 1, the disconnection determination process is performed using only equations (2) and (4).

[0053] Next, the operation of the disconnection detection device 33 will be described using a flowchart. Fig. 12 shows a flowchart explaining the operation of the disconnection detection device 33 according to the second embodiment. The disconnection detection device 33 repeatedly executes the disconnection detection process shown in Fig. 12 at a predetermined timing or period.

[0054] 12, when the disconnection detection device 13 starts the disconnection detection process, it first initializes i, which indicates the number of the detection line that is the target of disconnection detection, to 1 (step S10). Next, in the disconnection detection device 33, the disconnection detection unit 46 reads the disconnection threshold from the disconnection threshold register 22, and also reads the detection voltages V[0] and V[k+1], which are dummy detection voltages, from the detection voltage register 45 (step S11). Furthermore, the disconnection detection device 33 causes the disconnection detection unit 46 to read the detection voltages V[1] to V[k] stored in the detection voltage register 45 using the detection voltage acquisition unit 43 (step S12).

[0055] The disconnection detection unit 46 then determines whether the voltage corresponding to i among the read dummy detection voltages and detection voltages satisfies the disconnection determination formulas shown in equations (2) to (4) (steps S14, S18, and S19). Specifically, first, it is determined whether i is 1 (step S13). If i is 1, it is determined in step S14 whether the detection voltage satisfies equation (2) (step S14). If i is not 1 and k is 2 or greater in step S13 (YES branch in step S16), it is determined whether i is 2 to k (step S17). If i is any of 2 to k in step S17, the disconnection detection unit 46 determines whether the detection line is disconnected based on equation (3) (step S18). Furthermore, if the condition is not satisfied in either step S16 or step S17, the disconnection detection unit 46 determines whether the detection line is disconnected based on equation (4) (step S19). If the condition is met in any one of steps S14, S18, and S19, the disconnection detection unit 46 notifies the upper system that a disconnection has occurred in the detection line Wi (step S15).

[0056] Furthermore, upon being notified of the occurrence of a disconnection, the upper system determines that the battery voltage of the battery corresponding to the disconnected detection line cannot be measured correctly, and sets the entire battery pack as a single battery block, thereby updating the value of k to 1 so that the entire battery pack can be treated as a single battery cell. Furthermore, since the maximum and minimum battery voltage values ​​are also updated with the update of k, the upper system updates the disconnection thresholds V[0] and V[k+1] based on the updated maximum and minimum battery voltage values ​​(step S20). Note that the maximum and minimum battery voltage values ​​when k is set to 1 are calculated from the voltage excluding the battery cell affected by the fault. The disconnection detection unit 46 then requests the processing of step S20, thereby terminating the disconnection detection processing.

[0057] On the other hand, if it is determined in steps S14, S18, and S19 that the voltage under consideration does not satisfy the disconnection determination formula, the disconnection detection unit 46 repeats the processes of steps S13 to S19 while incrementing i by 1 until i becomes k+1 or greater (steps S21 and S22).

[0058] As explained above, in the second embodiment, a calculated value is used as the dummy detection voltage. As a result, in the battery unit 2 according to the second embodiment, even if the number of battery cells included in one battery block is changed in the event of a disconnection in the detection line that prevents the battery voltage from being measured or a failure in the voltage measurement circuit (not shown), open circuit detection can be continued without changing the open circuit determination formula. Furthermore, in the battery unit 2 according to the second embodiment, the same open circuit determination formula can be used regardless of the value of k, eliminating factors that may cause malfunctions, such as switching the open circuit determination formula, thereby improving safety.

[0059] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0060] 1 Battery unit 2 Battery Unit 11 Switch unit 12 Detection voltage generation circuit 13. Disconnection detection device 21 Disconnection threshold saving processing unit 22 Break Threshold Register 23 Detected voltage acquisition unit 24 Dummy detection voltage storage processing section 25 Detect Voltage Register 26 Disconnection detection unit 31 Switch unit 33 Disconnection detection device 41 Disconnection threshold saving processing unit 43 Detected voltage acquisition unit 45 Detect Voltage Register 46 Disconnection detection unit

Claims

1. A wire break detection program executed by a calculation unit in a battery voltage detection device that detects the voltages of k battery cells connected in series, where k is an integer, using k+1 detection lines connected via switches to electrodes of the k+1 battery cells, the program detecting wire breaks in the battery voltage detection device, a battery voltage acquisition process in which the switches connected to the positive and negative electrodes of the first to kth battery cells are selectively turned on, and the battery voltages of the first to kth battery cells are measured and acquired as detected voltages; a dummy voltage acquisition process for storing a measurement value obtained by measuring the voltage of the first battery cell without using the second detection line as a 0th detection voltage to be compared with the detection voltage of the first battery cell, and a measurement value obtained by measuring the voltage of the kth battery cell without using the k-1th detection line as a k+1th detection voltage to be compared with the detection voltage of the kth battery cell in a dummy detection voltage register; a threshold reading process for reading a break threshold value for determining whether the detection line is broken from a break threshold register; a dummy detection voltage reading process for reading a 0th detection voltage and a k+1th detection voltage from the dummy detection voltage register; a detected voltage acquisition process for acquiring the voltages detected from the battery cells as first to k-th detected voltages in order from the battery cells arranged on the high potential side; a disconnection detection process for determining that a disconnection exists in a detection line that satisfies a disconnection determination condition by applying the 0th to the k+1th detection voltages and the disconnection threshold value to the disconnection determination condition; and The battery voltage detection device further includes a 0th detection line that detects the same voltage as the 2nd detection line, and a k+2th detection line that detects the same voltage as the kth detection line, the 0th detection voltage is a potential difference obtained between the 0th detection line and the 1st detection line, and the k+1th detection voltage is a potential difference obtained between the k+1th detection line and the k+2nd detection line; In the disconnection detection process, Using equation (1) in which the i-th detection voltage is expressed as V[i] as the disconnection determination condition, it is determined that a disconnection has occurred in the 1st to k+1th detection lines that satisfy equation (1). i = 1 to k + 1: V[i-1] < disconnection threshold, and V[i] < disconnection threshold (1) Disconnection detection program.

2. A battery voltage detection device detects the voltages of k battery cells connected in series using k+1 detection lines, where k is an integer, and the detection lines are connected to electrodes of the k+1 battery cells via switches, and the method detects breaks in the detection lines by performing calculations, a battery voltage acquisition process in which the switches connected to the positive and negative electrodes of the first to kth battery cells are selectively turned on, and the battery voltages of the first to kth battery cells are measured and acquired as detected voltages; a dummy voltage acquisition process for storing a measurement value obtained by measuring the voltage of the first battery cell without using the second detection line as a 0th detection voltage to be compared with the detection voltage of the first battery cell, and a measurement value obtained by measuring the voltage of the kth battery cell without using the k-1th detection line as a k+1th detection voltage to be compared with the detection voltage of the kth battery cell in a dummy detection voltage register; a threshold reading process for reading a break threshold value for determining whether the detection line is broken from a break threshold register; a dummy detection voltage reading process for reading a 0th detection voltage and a k+1th detection voltage from the dummy detection voltage register; a detected voltage acquisition process for acquiring the voltages detected from the battery cells as first to k-th detected voltages in order from the battery cells arranged on the high potential side; a disconnection detection process for determining that a disconnection exists in a detection line that satisfies a disconnection determination condition by applying the 0th to the k+1th detection voltages and the disconnection threshold value to the disconnection determination condition; and The battery voltage detection device further includes a 0th detection line that detects the same voltage as the 2nd detection line, and a k+2th detection line that detects the same voltage as the kth detection line, the 0th detection voltage is a potential difference obtained between the 0th detection line and the 1st detection line, and the k+1th detection voltage is a potential difference obtained between the k+1th detection line and the k+2nd detection line; In the disconnection detection process, Using equation (1) in which the i-th detection voltage is expressed as V[i] as the disconnection determination condition, it is determined that a disconnection has occurred in the 1st to k+1th detection lines that satisfy equation (1). i = 1 to k + 1: V[i-1] < disconnection threshold, and V[i] < disconnection threshold (1) Disconnection detection method.

3. A wire break detection device that detects wire breaks in k+1 detection lines, each of which is connected via a switch to k+1 electrodes provided on k battery cells connected in series, where k is an integer, comprising: a detection voltage acquisition unit that performs a battery voltage acquisition process in which the switches connected to the positive and negative electrodes of the first to kth battery cells are selectively turned on to acquire the measured battery voltages of the respective battery cells as detection voltages; and a dummy voltage acquisition process in which a measurement value of the voltage of the first battery cell measured without using the second detection line is set as a 0th detection voltage to be compared with the detection voltage of the first battery cell, and a measurement value of the voltage of the kth battery cell measured without using the k-1th detection line is stored in a dummy detection voltage register as a k+1th detection voltage to be compared with the detection voltage of the kth battery cell; a disconnection threshold register that stores a disconnection threshold for determining whether the detection line is disconnected; a dummy detection voltage register in which the 0th detection voltage and the k+1th detection voltage are stored as dummy detection voltages; a disconnection detection unit that applies the 0th to the k+1th detection voltages and the disconnection threshold value to a disconnection determination condition and determines that a detection line that satisfies the disconnection determination condition has a disconnection; and Further, the 0th detection line detects the same voltage as the 2nd detection line, and the k+2th detection line detects the same voltage as the kth detection line, the 0th detection voltage is a potential difference obtained between the 0th detection line and the 1st detection line, and the k+1th detection voltage is a potential difference obtained between the k+1th detection line and the k+2nd detection line; In the disconnection detection unit, Using equation (1) in which the i-th detection voltage is expressed as V[i] as the disconnection determination condition, it is determined that a disconnection has occurred in the 1st to k+1th detection lines that satisfy equation (1). i = 1 to k + 1: V[i-1] < disconnection threshold, and V[i] < disconnection threshold (1) Wire break detection device.

4. The disconnection detection device according to claim 3 , wherein the 0th to the k+2th detection lines are provided with switches that switch whether or not the voltage of the electrode is transmitted to the detection voltage acquisition unit.

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