JP2010025824A - Battery pack monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the variations of current consumption of a battery pack which is caused by power consumption of a photocoupler in a battery pack monitoring device 1 of ladder form, because the photocoupler disposed in a block Bn on the most downstream side consumes the power of the block Bn whenever current-to-light transference is performed, and so the power consumption of the block Bn becomes larger than that of other blocks B1-B(n-1), because the battery pack monitoring device 1 of a ladder constitution transmits a signal by the current-to-light transference. <P>SOLUTION: The most upstream-side monitoring unit U1 and relay monitoring units U2-U(n-1) have discharge means which discharge the block being a monitoring object, according to a state of turning-on of electricity of an insulating element 22 located on the downstream side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an assembled battery monitoring device that monitors the state of charge of an assembled battery in which a plurality of cells are connected in series.

  In hybrid vehicles that have been attracting attention in recent years, lithium ion batteries with high energy efficiency have been attracting attention. While this lithium ion battery has the advantage of a large capacity, there is a risk that overcharge may cause heat generation and ignition, and overdischarge will result in electrode elution and a decrease in life. Therefore, it is common to connect an assembled battery monitoring device that monitors the charge state of each block to the lithium ion battery.

  Since a control device that controls such an assembled battery monitoring device is driven at a low pressure, signals are transmitted between the assembled battery monitoring device and the control device usually using an insulating element such as a photocoupler. Since such insulating elements are expensive, it is desirable that the number of them used be small. In order to solve such a problem, for example, as shown in FIG. 1 of Patent Document 1, an assembled battery monitoring device having a so-called ladder configuration in which the input and output of a monitoring unit are connected in series has been proposed.

A ladder-structured assembled battery monitoring device will be described with reference to FIG. The monitoring unit U1 located at the most upstream receives an instruction signal instructing monitoring of the battery state from the control device (microcomputer), and generates a state signal that is a result of monitoring based on the instruction signal. Then, the instruction signal and the status signal are successively transmitted from the monitoring unit U1 to the monitoring unit U2 to the monitoring unit Un. The status signal is updated according to the monitoring result of each monitoring unit, and the monitoring unit Un located most downstream transmits the status signal to the control device via the photocoupler located downstream. In the battery pack monitoring device with a ladder configuration, only the monitoring units at both ends exchange information directly with the control device on the low voltage side, so it is only necessary to place photocouplers in the most upstream block and the most downstream block. There is an advantage that the number of can be reduced.
JP 2007-278913 A

  However, since the assembled battery monitoring device of the ladder configuration transmits a signal by electro-optic conversion, the downstream photocoupler connected to the cells Bn1 to Bnm which are the most downstream blocks each time the electro-optic conversion is performed. It consumes Bn1-Bnm power. For this reason, the power consumption of the cells Bn1 to Bnm is increased compared to the other cells B11 to B (n-1) m. As a result, there has been a problem that the variation in the charged state is widened and the use area of the charged state of the assembled battery is narrowed.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce variations in current consumption of assembled batteries in a ladder-type assembled battery monitoring apparatus.

  The invention according to claim 1 is a monitoring unit that monitors the state of charge of a cell for each block unit with respect to an assembled battery formed by connecting a plurality of blocks composed of a single cell or a series connection of a plurality of cells in series. In the assembled battery monitoring device configured as a series connection body, the most upstream monitoring unit located at the most upstream sends an instruction signal from the control unit that instructs the monitoring unit to monitor the battery state via the upstream insulating element. The most downstream monitoring unit that receives and sends the final monitoring result signal indicating the monitoring result of all blocks to the control unit via the downstream insulating element, and between the most upstream monitoring unit and the most downstream monitoring unit. The relay monitoring unit located at the downstream receives a status signal that reflects the monitoring result of the relay monitoring unit in the monitoring result of the upstream monitoring unit transmitted from the upstream monitoring unit. It is one that transmits to the monitoring unit, the relay monitoring unit and the most upstream monitoring unit is characterized by having a discharging means for discharging the block to be monitored in accordance with the current state of the downstream insulation element.

  In the above configuration, since the discharging means of the most upstream monitoring unit and the discharging means of the relay monitoring unit are discharged according to the energization state of the downstream insulating element, only the charging state of the most downstream block is caused by the downstream insulating element. However, it is possible to reduce the situation where the charging state varies due to the lowering of the charging state of the other blocks.

  The invention according to claim 2 is characterized in that the energized state is determined based on a final monitoring result signal.

  In the above configuration, whether or not the downstream insulating element is energized is determined based on the final monitoring result signal. As a result, the energization state of the downstream insulation element can be grasped without providing a current sensor or the like in the energization path of the downstream insulation element.

  According to a third aspect of the present invention, the relay monitoring unit and the most downstream monitoring unit have final monitoring result transmission means for transmitting a final monitoring result signal to an upstream monitoring unit, and the most upstream monitoring unit and the relay monitoring unit perform final monitoring. The discharging means is discharged based on the result signal.

  In the above configuration, the most upstream monitoring unit and the relay monitoring unit can grasp whether the battery state is transmitted to the downstream insulating element via the final monitoring result transmission unit. As a result, even when the downstream monitoring unit generates a state signal for energizing the downstream insulating element, the upstream monitoring unit can recognize that fact.

  The invention according to claim 4 is characterized in that the monitoring unit enters a discharge state in accordance with the final monitoring result signal and the status signal.

  In the above configuration, in the case where there is a difference in power consumption of each monitoring unit due to a difference in status signal, the power consumption varies based on the difference in status signal by discharging the discharge circuit of the monitoring unit with low power consumption. Can be reduced.

  In the invention according to claim 5, the status signal represents the status of the signal by a level based on the magnitude of the voltage or current, and the level of the status signal output as the output signal from the monitoring unit and to the monitoring unit Discharging means for a monitoring unit located upstream from a specific monitoring unit when a specific monitoring unit having a different level of the state signal input as an input signal is detected and the level of the output signal is greater than the level of the input signal When the level of the output signal is smaller than the level of the input signal, the discharging means of the specific monitoring unit and the discharging means positioned downstream of the monitoring unit are discharged.

  In the above configuration, a specific monitoring unit having a different input signal level and output signal level is detected, and the preceding and following monitoring units are discharged with the monitoring unit as a base point. As a result, it is possible to reduce the variation in the charging state between the blocks due to the difference in the energized state due to the state signal.

  The invention according to claim 6 is characterized in that the instruction signal further includes information indicating the total discharge command, and the monitoring unit that has received the instruction signal indicating the total discharge command sets the discharge means to the discharge state.

  In the case where an abnormality occurs in the overcharge prevention function and charging continues even in a situation where charging should be stopped, the role of fail-safe to alleviate the adverse effects of abnormal charging by forcibly discharging all the discharge means Can fulfill.

  In the invention according to claim 7, the instruction signal further includes information indicating a diagnosis instruction of the monitoring unit and the block, and the monitoring unit discharges the discharging means in response to the diagnosis support to charge the monitoring target block. And measuring whether or not there is an abnormality in the monitoring unit or the block to be monitored based on the amount of change.

  The monitoring unit that has received the instruction signal indicating the diagnosis instruction discharges the discharging means and measures the amount of change in the state of the electric current of the monitored block, so that the discharging means operates accurately based on the measurement result. A checking function for diagnosing an abnormality in the monitoring unit such as whether or not can be achieved.

Example 1
FIG. 1 shows an assembled battery monitoring device 1 for monitoring the state of charge of an assembled battery according to Embodiment 1 of the present invention, and FIG. 2 shows a block circuit diagram of a monitoring unit.

  The assembled battery 10 is configured by further connecting a plurality of blocks BL formed of a single cell or a series connection of a plurality of cells in series. In the uppermost block, cells BL1 to B1m are connected in series to form a block BL1, and the second and subsequent blocks BL2 to BLn are also formed by connecting cells in series. The assembled battery 10 is formed by connecting blocks BL1 to BLn in series.

  Each block BL1 to n of the assembled battery 10 is connected to monitoring units U1 to Un that monitor the state of charge of the cell, and monitoring the assembled battery by using a series connection body in which the monitoring units U1 to Un are connected in series. The apparatus 1 is configured. The assembled battery monitoring device 1 and the block are arranged in parallel.

For example, in the block BL1, the monitoring unit U1 is connected, and the battery states of the cells B11, B12,..., Cell B1m are monitored. The monitoring unit U monitors whether the battery state is a normal state or an abnormal state such as overcharge or overdischarge. Even when overcharge is monitored, a plurality of overcharge states can be monitored according to the cell level.
While the assembled battery monitoring device 1 is connected to a high voltage assembled battery 10, a microcomputer (control unit (not shown)) that instructs the assembled battery monitoring device 1 to perform processing such as monitoring of the battery state is a low-voltage system. Therefore, it is arranged on the low pressure side. For this reason, it is necessary to arrange the insulating elements 21 and 22 between the assembled battery monitoring device 1 and the microcomputer to electrically insulate them. Examples of the insulating element include a photocoupler. The microcomputer transmits an instruction signal for instructing monitoring of the battery state or the like to the most upstream monitoring unit U1 via the upstream photocoupler 21. The most upstream monitoring unit U1 located at the most upstream receives the instruction signal from the microcomputer, and the most upstream monitoring unit U1 determines whether the monitoring block is in a state (overcharge / overdischarge) indicated by the instruction signal. Monitor and generate a status signal that is the monitoring result. Then, the instruction signal and the status signal are transmitted to the monitoring unit U2 located downstream. The monitoring unit U2 also monitors whether the monitoring block is in a state indicated by the instruction signal (overcharge / overdischarge, etc.), and updates the state signal from the upstream monitoring unit U1 based on the monitoring result.

  Then, the monitoring unit U2 transmits the status signal and the instruction signal to the monitoring unit U3. In this way, the relay monitoring units U2 to U (n-1) receive the instruction signal and the status signal from the upstream monitoring units U1 to U (n-2), update the status signal, and the status signal and the instruction. The signal is transmitted to the downstream monitoring units U3 to Un. In other words, the relay monitoring units U2 to U (n-1) are connected to the monitoring results (status signals) of the upstream monitoring units transmitted from the upstream monitoring units U1 to U (n-2). -1) The state signal reflecting the monitoring result (monitoring signal) is transmitted to the downstream monitoring units U3 to Un. The instruction signal and the status signal finally reach the most downstream monitoring unit Un located on the most downstream side. The most downstream monitoring unit Un located on the most downstream side performs monitoring according to the instruction signal, and combines the monitoring result with the status signal from the upstream monitoring unit U (n−1), that is, all blocks. The final monitoring result signal indicating the monitoring result is transmitted to the microcomputer side via the downstream photocoupler 22. In this way, since only the most upstream monitoring unit U1 and the most downstream monitoring unit Un exchange information directly with the microcomputer, the number of photocouplers, which are expensive insulating elements, can be minimized. . The relay monitoring units U2 to U (n-1) and the most downstream monitoring unit Un have final monitoring result transmission means 26 for transmitting the final monitoring result signal to the upstream monitoring units U1 to U (n-2). All the monitoring units U can grasp the monitoring result signal.

  For the sake of convenience, in the signal flow of the assembled battery monitoring device 1, the monitoring unit that receives the instruction signal first is called upstream, and the monitoring unit that receives the instruction signal later is called downstream.

  The monitoring unit U has a CLK terminal for inputting an instruction signal, a CKLOUT terminal for outputting an instruction signal, an IN terminal for inputting an input signal (a state signal output by an upstream monitoring unit), and an OUT terminal for outputting a state signal. , Monitoring means 23, discharging means 24, and synthesizing means 25. Here, the monitoring unit 23 generates a monitoring signal by monitoring the battery state of the cells in the block connected to the monitoring unit U according to the instruction signal.

  The monitoring unit U monitors the battery state (over discharge / overcharge) indicated by the instruction signal input from the CLK terminal by the monitoring unit 23, and generates a monitoring signal indicating the monitoring result. The IN terminal receives the status signal output from the monitoring unit adjacent upstream as an input signal, and the synthesizing unit 25 generates (updates) the status signal based on the input signal and the monitoring signal. Is output from the OUT terminal which is output means. The instruction signal is also output from the CLKOUT terminal to the downstream monitoring unit. Since the upstream monitoring unit U1 has no upstream monitoring unit, a state signal indicating a normal state is always input.

  The discharge circuit 24, which is the discharge means 24, discharges based on a predetermined signal. The discharge circuit 24 may be provided for each block or for each cell. Examples of the configuration of the discharge circuit 24 include a series connection body of a switch and a constant current circuit, and a series connection body of a switch and a resistor. The discharge circuit 24 may be provided inside the monitoring unit U or outside the monitoring unit U.

  FIG. 3 shows a comparison between the detected battery state and the current state of each terminal in the assembled battery monitoring device according to the first embodiment of the present invention. Hereinafter, the current flow of each line according to the instruction signal and the state signal will be described.

  The detection battery state shown in FIG. 3 will be described. CLK is an instruction signal, IN is a status signal from an upper monitoring unit, OUT1 is a monitoring signal generated by the monitoring unit U monitoring the monitoring block, and OUT is a status signal output from the monitoring unit U. When CLK is 0, overcharge monitoring is instructed, and when CLK is 1, overdischarge monitoring is instructed. IN indicates that overcharge is detected, 1 indicates overcharge, 0 indicates normal, and if overdischarge is detected, 1 indicates normal and 0 indicates overdischarge. When OUT1 is overcharge detected, 0 indicates overcharge, 1 indicates normal, and when overdischarge is detected, 1 indicates overdischarge and 0 indicates normal. OUT indicates that overcharge is detected, 1 indicates that at least one of the upper cell and the current cell is overcharged, and 0 indicates normal. If overdischarge is detected, 0 indicates that at least one of the upper cell and the current cell is excessive. Discharge 1 indicates normal.

  The currents 1a to 1c and the currents 2a to 2c will be described. The current 1a is a current that flows through the upper photocoupler when a signal is transmitted by the upper photocoupler, and consumes the power of the block B1. The current 1b is a current that flows through the CLK terminal of the highest level monitoring unit U1, and transmits an instruction signal (CLK signal). When overcharge monitoring is instructed, current does not flow, and when overdischarge monitoring is instructed, current flows. The current 1c is a current that flows through a signal line connecting the CLK terminal of the monitoring unit U and the CLKOUT terminal of the monitoring unit of the upper block, and transmits an instruction signal (CLK signal). When overcharge monitoring is instructed, current does not flow, and when overdischarge monitoring is instructed, current flows.

  The current 2a is a current flowing through the IN terminal of the highest level monitoring unit U1, and the IN terminal is a terminal for inputting a status signal monitored by the higher level monitoring unit. In the case of the highest level monitoring unit U1, since a monitoring result from a higher level is not received, a current indicating a normal state signal always flows. That is, the current 2a does not always flow when detecting overcharge, and the current 2a always flows when detecting overdischarge. The current 2b is a current that flows in a signal line that connects the input terminal (IN terminal) of the monitoring unit U to the output terminal (OUT terminal) from a higher-level monitoring unit, and the monitoring unit U transmits a status signal that is a monitoring result. To do. When overcharge is detected, current flows when overcharge is detected, and no current flows when normal. When overdischarge is detected, current does not flow if overdischarge is detected, and current flows if normal. The current 2c is a current that flows when a signal is transmitted by the lower photocoupler, and consumes the power of the block Bn. Here, the transmitted signal is a signal indicating the monitoring result of overcharge or overdischarge. When overcharge is detected, the signal is transmitted when overcharge is detected, and when normal is detected, the signal is transmitted. Is not transmitted. On the other hand, when detecting overdischarge, a signal is transmitted when normality is detected, and no signal is transmitted when overdischarge is detected.

  A light receiving element such as a phototransistor that is turned on by receiving an optical signal is disposed on the high voltage side of the upstream photocoupler 21, and a high voltage side of the downstream photocoupler 22 is a light emitting diode that photoelectrically converts an electrical signal into an optical signal. Etc. are arranged. Since the light emitting element consumes more power than the light receiving element, the power consumption of the block Bn by the lower photocoupler is larger than the power consumption of the block B1 by the upper photocoupler.

  The currents S1a and S2c are currents that flow when the discharge circuit 24 is discharged. The current S1a is caused to flow in the lowest order monitoring unit Un and the relay monitoring units U2 to U (n-1) in response to the signal being transmitted in the higher order photocoupler. Therefore, when the current 1a flows, the current S1a also flows. When the current 1a does not flow, the current S1a does not flow.

  By controlling in this way, it is possible to reduce a situation in which the charging state of the uppermost block B1 is lower than the charging state of the other blocks due to the current from the upper photocoupler.

  The current S2c is a current that flows in the uppermost monitoring unit U1 and the relay monitoring units U2 to U (n−1) when a signal is transmitted in the lower and upper photocouplers. Therefore, when the current 2c flows, the current S2c also flows, and when the current 2c does not flow, the current S2c does not flow.

  By controlling in this way, it is possible to reduce the situation where the state of charge of the lowest block Bn is lower than the state of charge of the other blocks due to the current from the lower photocoupler.

  FIG. 4 shows a state transmission circuit I / F according to the first embodiment. The state transmission circuit I / F is a circuit that transmits a signal (instruction signal / final monitoring result signal) for discharging the discharge circuit 24 and controls on / off of the discharge circuit 24.

  The state transmission circuit I / F includes two lines, a forward flow line L1 for transmitting a signal from upstream to downstream and a line L2 for transmitting a signal from downstream to upstream. The backflow line L2 serves as a final monitoring result transmission means 26 that transmits a final monitoring result signal indicating the monitoring results of all blocks to the upstream monitoring unit.

  The state transmission circuit I / F outputs a signal having the same level as the signal input to the L1 input from S1a and L1 output, and outputs a signal having the same level as the signal input to the L2 input from S2c and L2 output.

  In the line L1, an instruction signal is transmitted from the upstream monitoring unit to the downstream monitoring unit via the state transmission circuit I / F. The transmitted instruction signal is branched from the instruction signal line input to the most upstream monitoring unit U1 and input to the state transmission circuit I / F1. The state transmission circuit I / F1 receives the instruction signal and outputs the instruction signal to the state transmission circuit I / F2. In this way, the instruction signal is transmitted as state transmission circuit I / F1 → state transmission circuit I / F2 →... → state transmission circuit I / F (n−1) → state transmission circuit I / Fn. The state transmission circuits I / F2 to I / Fn use the discharge circuit 24 to discharge the corresponding block in response to the instruction signal. That is, when the instruction signal indicates overcharge detection (when CLK is 0 and the current 1a does not flow), the discharge circuits 24 of the blocks B2 to Bn are not discharged, and when the instruction signal indicates overdischarge detection (CLK is 1). When the current 1a flows), the discharge circuits 24 of the blocks B2 to Bn are discharged and the current S1a flows. Thus, when a current flows through the upstream photocoupler 21, the discharge circuits 24 of the relay monitoring units U2 to U (n-1) and the most downstream monitoring unit Un are discharged, and a current S1a is supplied.

  In the line L2, which is the final monitoring result transmission means 26, the final monitoring result signal output from the most downstream monitoring unit Un (the state signal output from the most downstream monitoring unit Un) is branched from downstream to upstream. Input to the state transmission circuit I / Fn. The state transmission circuit I / Fn transmits the final monitoring result signal to the state transmission circuit I / F (n−1) located upstream. In this way, the final monitoring result signal is transmitted in the order of state transmission circuit I / Fn → state transmission circuit I / F (n−1) →... → state transmission circuit I / F2 → state transmission circuit I / F1. To go. The state transmission circuits I / F1 to I / F (n-1) discharge the corresponding block using the discharge circuit 24 in accordance with the final monitoring result signal transmitted from the downstream. That is, if the final monitoring result signal indicates overcharge when overcharge is detected or indicates normality when overdischarge is detected, the discharge circuit 24 of the blocks B1 to B (n-1) is discharged and the current S2c flows. When the final monitoring result signal indicates normality when overcharge is detected, or when overdischarge is detected when overdischarge is detected, the blocks B1 to B (n-1) are not discharged. Thus, when a current flows through the downstream photocoupler 22, the discharge circuit 24 of the most upstream monitoring unit U1 and the relay monitoring units U2 to U (n-1) is discharged, and the current S2c is supplied.

  Note that the power consumption of the current 1a and the power consumption of the current S1a, and the power consumption of the current 2c and the power consumption of the current S2c are preferably equal.

In the first embodiment, the final monitoring result signal is sent from the most downstream monitoring unit Un → the relay monitoring unit U (n−1) → the relay monitoring unit U via the state transmission circuit I / F and the final monitoring result transmission means 26. (N-2) → ... → relay monitoring unit U (n-1) → upstreammost monitoring unit U1 is transmitted in this order, but without providing the state transmission circuit I / F and the final monitoring result transmission means 26. The microcomputer that has received the final monitoring result signal may transmit the final monitoring result signal via the upstream photocoupler 21 again. In this case, the final monitoring result signal is the most downstream monitoring unit Un → the downstream photocoupler 22 → the microcomputer → the upstream photocoupler 21 → the most upstream monitoring unit U1 → the relay monitoring unit U2 →... → the relay monitoring unit U (n−1). And communicate.
(Example 2)
FIG. 5 shows signal waveforms when the monitoring signal of the monitoring unit and the status signal from the upstream monitoring unit indicate a normal state. It should be noted that here, in order to briefly explain the means for eliminating the variation in power consumption due to the difference in battery state transmitted by the state signal, the variation in power consumption due to the photocoupler is not considered.

  The top signal waveform in FIG. 5 shows the waveform of the instruction signal. The instruction signal is transmitted from the control unit that controls the monitoring unit U, and instructs the monitoring unit U to monitor the battery state. When the instruction signal is at the H level, the monitoring unit U enters an overdischarge detection mode for monitoring whether or not the monitored block is in an overdischarged state. When the instruction signal is at the L level, the monitoring unit U has exceeded the monitored block. The overcharge detection mode for monitoring whether or not charging is performed.

  The second signal waveform from the top in FIG. 5 shows the waveform of the input signal which is the status signal of the adjacent upstream monitoring unit. In the overdischarge detection mode, an H level signal indicates that no overdischarge block has been detected in the upstream monitoring unit, and an L level signal indicates that an overdischarge block has been detected in the upstream monitoring unit. Show. The overcharge detection mode is reversed, the L level signal indicates that no overcharge block has been detected in the upstream monitoring unit, and the H level signal has detected an overcharge block in the upstream monitoring unit. It shows that.

  The second signal waveform from the bottom in FIG. 5 shows the signal waveform of the monitoring signal. This case is the same as the case of the input signal. In the overdischarge detection mode, the H level signal indicates that the overdischarge block is not detected in its own monitoring unit, and the L level signal is Indicates that an overdischarge block has been detected in the monitoring unit. The overcharge detection mode is reversed, an L level signal indicates that no overcharge block has been detected in its own monitoring unit, and an H level signal has detected an overcharge block in its own monitoring unit. It shows that.

  The signal waveform at the bottom of FIG. 5 shows the status signal output from the monitoring unit U. In the overdischarge detection mode, an H level signal indicates that an overdischarge block is not detected in its own monitoring unit U and upstream monitoring unit, and an L level signal indicates its own monitoring unit U and upstream monitoring. Indicates that an overdischarge block has been detected in at least one of the units. The overcharge detection mode is reversed, and an L level signal indicates that an overcharge block is not detected in its own monitoring unit U and upstream monitoring unit, and an H level signal indicates that its own monitoring unit U and upstream. This indicates that an overcharge block has been detected in at least one of the monitoring units.

  As described above, the instruction signal, the status signal, and the monitoring signal indicate the signal status by the level (H level or L level) based on the magnitude of the voltage or current. In the overdischarge detection mode, the level of the state signal output as an output signal from the monitoring unit U is equal to or higher than the level of the state signal input as an input signal to the monitoring unit U. In the overcharge detection mode, the level of the state signal output as an output signal from the monitoring unit U is equal to or lower than the level of the state signal input as an input signal to the monitoring unit U. When the level of the status signal output as the output signal from the monitoring unit U is different from the level of the status signal input as the input signal to the monitoring unit U, the status signal is transmitted between the output line and the input line. The electric power required for this will differ. As a result, a mechanism of variation in power consumption and a method for equalizing the variation will be described below.

  FIG. 6 shows a signal waveform when the monitoring signal of the monitoring unit indicates overdischarge and the status signal from the upstream monitoring unit indicates a normal state.

  As shown in the bottom signal waveform and the second signal waveform from the bottom in FIG. 6, when overdischarge occurs, the monitor signal and the status signal are always L level signals. As a result, even when the input signal is at the H level, the output signal is at the L level, and the power consumed by the input line of the monitoring unit U is larger than the power consumed by the output line of the monitoring unit U. As a result, in the monitoring unit U and later, power consumption is reduced, which causes battery variations between blocks.

  FIG. 7 shows a signal waveform when the monitoring signal of the monitoring unit indicates overcharge and the state signal from the upstream monitoring unit indicates a normal state.

  As shown in the bottom signal waveform and the second signal waveform from the bottom in FIG. 7, when overcharge occurs, the monitoring signal and the status signal are always H level signals. As a result, even when the input signal is at the L level, the output signal is at the H level, and the power consumed by the input line of the monitoring unit U is smaller than the power consumed by the output line of the monitoring unit U. As a result, in the monitoring unit upstream of the monitoring unit U, power consumption is reduced, which causes battery variation between blocks.

  FIG. 8 is a flowchart in the second embodiment of the present invention, FIG. 9 is a state of discharge of each block in the overdischarge detection mode in the second embodiment of the present invention, and FIG. 10 is each flowchart in the overcharge detection mode in the second embodiment of the present invention. The state of discharge of a block is shown.

  FIG. 8 will be described. First, in step 100, it is determined whether the overcharge detection mode or the overdischarge detection mode. In the overdischarge detection mode, the process proceeds to step 120, and in the overcharge detection mode, the process proceeds to step 110. In step 110, the final monitoring result signal is acquired, and it is determined whether or not the final monitoring result signal is at a high level. When the final monitoring result signal indicates the low level in the overcharge detection mode, the state signal is at the low level in all the blocks, and there is no variation in power consumption due to the transmission of the state signal. Therefore, when the final monitoring result signal is at the low level, the determination is finished. On the other hand, when the final monitoring result signal is at the high level, the process proceeds to step 120, where it is determined whether or not the status signal of the monitoring unit U performing the discharge determination is at the low level. In the case of the High level, the power consumption required for the state signal transmission between the most downstream monitoring unit and the monitoring unit performing the discharge determination is equal, so nothing is performed and the process is terminated. On the other hand, in the case of the Low level, the power consumption required for transmitting the state signal is smaller than that of the most downstream monitoring unit Un, and therefore the discharge circuit 24 is discharged. The amount of discharge at this time corresponds to the power consumption when a high level state signal is transmitted.

  The state of discharge of the discharge circuit in the overdischarge detection mode will be described with reference to FIG. In FIG. 9, overdischarge is detected in the monitoring unit U4. Since the H level state signal is transmitted during normal operation and the L level state signal is transmitted during overdischarge, the monitoring units U1 to U3 have a larger discharge amount than the monitoring units U4 to U6. Therefore, the monitoring units U4 to U6 discharge the discharge circuit 24 to equalize power consumption in the monitoring units U1 to U6.

  As described above, in FIG. 9, the monitoring unit U4 is detected as a specific monitoring unit in which the level of the state signal as the output signal from the monitoring unit is different from the level of the state signal input as the input signal to the monitoring unit. In FIG. 9, this corresponds to the case where the level of the output signal of the monitoring unit U4 is smaller than the level of the input signal, and the discharge circuit 24 of the monitoring unit U4 and the monitoring units U5 and U6 located downstream of the monitoring unit U4. The discharge circuit 24 is discharged. In the flowchart of FIG. 8, when the state signal of the most upstream monitoring unit U1 is L level, the discharge circuit 24 of the most upstream monitoring unit U1 is discharged. However, when the most upstream monitoring unit U1 transmits an L level state signal in the overdischarge detection mode, all the monitoring units U1 to Un transmit an L level state signal, so the most upstream monitoring unit. If the status signal of U1 is at L level, there is of course no problem even if all the monitoring units U1 to Un perform the process of not discharging.

  On the other hand, the discharge state of the discharge circuit 24 in the overcharge detection mode will be described with reference to FIG. In FIG. 10, overcharge is detected in the monitoring unit U4. Since the L level state signal is transmitted during normal operation and the H level state signal is transmitted during overcharge, the monitoring units U1 to U3 have a smaller discharge amount than the monitoring units U4 to U6. Since the monitoring unit U does not know the state of the status signal of the monitoring unit located downstream from itself, the final monitoring result signal, which is the status signal of the most downstream monitoring unit Un, is transmitted from downstream to upstream, and the final monitoring result signal And the status signal of the monitoring unit that performs the discharge determination are compared to determine whether or not the discharge is necessary. In the case of FIG. 10, the monitoring units U <b> 1 to U <b> 3 having a state signal at a level lower than the final monitoring result signal discharge the discharge circuit 24 to equalize the power consumption in the monitoring units U <b> 1 to U <b> 6.

  As described above, in FIG. 10, the monitoring unit U4 is detected as a specific monitoring unit in which the level of the state signal as the output signal from the monitoring unit U is different from the level of the state signal input as the input signal to the monitoring unit U. In FIG. 10, this corresponds to the case where the level of the output signal of the monitoring unit U4 is higher than the level of the input signal, and the discharge circuits 24 of the monitoring units U1 to U3 located upstream of the monitoring unit U4 are discharged.

  The discharge circuit 24 for eliminating the variation in power consumption due to the difference in the battery state to which the status signal is transmitted may be shared with the discharge circuit 24 for eliminating the variation in power consumption due to the photocoupler, A new discharge circuit 24 may be provided in parallel with the discharge circuit 24 for eliminating variations in power consumption.

  In addition, you may add the following functions to said Example 1 and Example 2. FIG.

  Information indicating the total discharge command may be included in the instruction signal so that the monitoring unit U can discharge the discharge circuit 24 in response to the instruction signal indicating the total discharge command. In the event of a charging abnormality such as being unable to stop charging despite being in an overcharged state, it is possible to reduce the effects of the charging abnormality by performing a full discharge command, and to play a role of fail-safe it can.

  The instruction signal may further include information indicating a diagnostic instruction for the monitoring unit and the block. In this case, the monitoring unit discharges the discharge circuit 24 according to the diagnosis instruction and measures the amount of change in the charge state of the monitored block. Then, based on the change amount, it is determined whether or not there is an abnormality in the monitoring unit U or the monitoring target block BL. For example, when there is no change amount, it can be determined that there is an abnormality in the discharge function of the monitoring unit U, and when the change amount is extremely larger than a specified value, it can be determined that there is an abnormality in the monitored block.

  In the above embodiment, the high potential side is defined as upstream and the low potential side is defined as downstream. However, the low potential side may be defined as upstream and the high potential side may be defined as downstream.

It is a figure which shows the whole structure of the assembled battery monitoring apparatus which concerns on Example 1 of this invention. It is a block diagram of the monitoring unit which concerns on Example 1 of this invention. It is a figure which shows the contrast of the detection battery state in the assembled battery monitoring apparatus which concerns on Example 1 of this invention, and the electric current state of each terminal. It is a state transmission circuit I / F which concerns on Example 1 of this invention. It is a signal waveform diagram in case the monitoring signal of the monitoring unit which concerns on Example 2 of this invention and the status signal from an upstream monitoring unit show a normal state. It is a signal waveform diagram in case the monitoring signal of the monitoring unit which concerns on Example 2 of this invention shows overdischarge, and the status signal from an upstream monitoring unit shows a normal state. It is a signal waveform diagram in case the monitoring signal of the monitoring unit which concerns on Example 2 of this invention shows overcharge, and the state signal from an upstream monitoring unit shows a normal state. It is a flowchart in Example 2 of this invention which concerns on Example 2 of this invention. It is a mode of discharge of each block in the overdischarge detection mode in Example 2 of this invention. It is a mode of discharge of each block in overcharge detection mode in Example 2 of the present invention.

Explanation of symbols

1 assembled battery monitoring device 10 assembled battery 21 upstream insulation element (upstream photocoupler)
22 Downstream insulation element (downstream photocoupler)
23 monitoring means 24 discharging means (discharge circuit)
25 Combining means 26 Final monitoring result transmitting means B, B11 to Bnm Cell BL, BL1 to BLn Block U, U1 to Un Monitoring unit

Claims (7)

Constructed as a series connection body of monitoring units that monitor the state of charge of the cell for each block unit, with respect to an assembled battery formed by connecting a plurality of blocks composed of a single cell or a series connection body of a plurality of cells in series. In the assembled battery monitoring device
The most upstream monitoring unit located at the most upstream receives an instruction signal from the control unit that instructs the monitoring unit to monitor the battery state via the upstream insulating element, and the most downstream monitoring unit located at the most downstream side The final monitoring result signal indicating the monitoring results of all blocks is sent to the control unit via the downstream insulating element, and the relay monitoring unit located between the most upstream monitoring unit and the most downstream monitoring unit A status signal reflecting the monitoring result of the relay monitoring unit in the monitoring result of the upstream monitoring unit transmitted from the monitoring unit is transmitted to the downstream monitoring unit;
The assembled battery monitoring apparatus, wherein the most upstream monitoring unit and the relay monitoring unit include discharge means for discharging a block to be monitored in accordance with an energization state of the downstream insulating element.   The assembled battery monitoring device according to claim 1, wherein the energization state is determined based on the final monitoring result signal.   The relay monitoring unit and the most downstream monitoring unit have final monitoring result transmission means for transmitting the final monitoring result signal to an upstream monitoring unit, and the most upstream monitoring unit and the relay monitoring unit have the final monitoring result signal. The assembled battery monitoring device according to claim 2, wherein the discharging means is discharged based on the battery.   The assembled battery monitoring device according to claim 3, wherein the monitoring unit discharges according to the final monitoring result signal and the state signal. The state signal represents the state of the signal by a level based on the magnitude of voltage or current,
Detecting a specific monitoring unit in which the level of the status signal output as an output signal from the monitoring unit is different from the level of the status signal input as an input signal to the monitoring unit;
When the level of the output signal is greater than the level of the input signal, the discharging means of the monitoring unit located upstream from the specific monitoring unit is discharged,
The discharge means of the specific monitoring unit and the discharge means located downstream of the monitoring unit are discharged when the level of the output signal is smaller than the level of the input signal. The assembled battery monitoring device according to any one of 4.   6. The instruction signal according to claim 1, wherein the instruction signal further includes information indicating a total discharge command, and the monitoring unit that receives the instruction signal indicating the total discharge command discharges the discharge means. The assembled battery monitoring device according to Item 1.   The instruction signal further includes information indicating a diagnosis instruction of the monitoring unit and the block, and the monitoring unit discharges discharging means in response to the diagnosis support to change a charging state of the monitoring target block. The assembled battery monitoring according to any one of claims 1 to 6, wherein an amount is measured and it is determined whether or not there is an abnormality in the monitoring unit or the block to be monitored based on the amount of change. apparatus.

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