JP2007010588A - Electric power source unit for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power source unit for a vehicle capable of detecting surely an overcharge of a battery block precisely to prolong a battery life. <P>SOLUTION: This electric power source unit: detects voltages of the plurality of battery blocks, by a determination device; detects a reference voltage variation (dV/dt) in a unit time of the whole battery block, and a module voltage variation (dVn/dt) in a specified time of the each battery block, based on the voltages of the detected respective battery blocks; integrates a difference between the reference voltage variation and the module voltage variation; computes a voltage variation integrated value (ΣädV/dt-dVn/dt}); and determines the overcharge of the battery block, based on the voltage variation integrated value (ΣädV/dt-dVn/dt}). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply device for a vehicle, and more particularly, to a power supply device including a determination device configured to detect a battery block in an overdischarge state by configuring a battery with a plurality of battery blocks.

  The power supply device for a vehicle increases the output voltage by connecting a large number of unit cells in series. This is to increase the output to the motor that drives the vehicle. This power supply device separates the battery into a plurality of blocks, and controls charging / discharging so as to prevent overcharging and overdischarging while detecting the state of the battery in units of blocks. This is because battery overcharge and overdischarge significantly deteriorate the battery and shorten the life. In the power supply device, for example, 5 to 6 unit cells are connected in series to form a battery module, and a plurality of battery modules are connected in series to increase the output voltage to 200 to 300V. This power supply device controls overcharge / discharge by detecting overdischarge and overcharge of a battery with one battery module as one block.

  By the way, in order to prevent overdischarge of the battery, a technique for detecting a decrease amount (dV / dt) of the battery voltage per unit time (dt) has been developed (see Patent Document 1). The warning device described in the gazette of Patent Document 1 employs voltage detection means for detecting the terminal voltage of a lead-acid battery, and an operation that takes this detection value and sequentially calculates changes per unit time of the detection value. Means, comparing means for comparing the calculated value with a reference value, and warning means for generating a warning when the calculated value by the calculating means becomes equal to or greater than the reference value. This alarm device detects an amount of decrease in battery voltage and prevents overdischarge. However, since this apparatus detects the voltage of the entire battery, it cannot divide the battery into a plurality of blocks and detect overdischarge of each battery. For this reason, in a vehicle power supply device in which a large number of unit cells are connected in series, overdischarge of a specific battery cannot be detected.

  An apparatus has been developed in which a battery is composed of a plurality of blocks and an abnormality of a specific battery block is detected (see Patent Documents 2 and 3). The battery control device described in the publication of Patent Document 2 includes a defective battery detection unit. The inconvenience detecting means is used when a battery having a large internal resistance during overcharge after an abnormal battery is detected, that is, when the difference in voltage change from the voltage change of a normal battery during overcharge is larger than a constant obtained from battery characteristics. The battery is determined to be a leaky battery. Also, a battery whose internal resistance does not increase during overcharge is determined as a micro short-circuit battery. The reason for this is that in a leaky battery, the internal resistance increases, so the battery voltage increases during charging, and the battery voltage decreases during discharging. This is because the voltage decreases but does not increase during charging.

Furthermore, the gazette of Patent Document 3 describes an assembled battery abnormality diagnosis apparatus in which a plurality of parallel blocks in which a plurality of unit cells are connected in parallel are connected in series. This device includes a voltage detecting means for detecting a voltage of each parallel block of the assembled battery, and a parallel connection cell in each parallel block based on a voltage change amount of each parallel block before and after discharging or charging a predetermined capacity of the assembled battery. And an abnormality determining means for determining the abnormality.
Japanese Patent Laid-Open No. 5-54275 JP 2003-204627 A JP 2004-31120 A

  Patent Documents 1 to 3 describe a technique for determining abnormality by detecting a voltage change amount (dV / dt) of a battery. Furthermore, a battery composed of a plurality of battery blocks can detect an overdischarge block more reliably by comparing a change in voltage of each battery block with a change in average voltage of each battery block. However, it is extremely difficult to reliably detect overdischarge of the battery block even in an apparatus that detects overdischarge of the battery block from the amount of voltage change based on the average voltage. This is because it is necessary to detect overdischarge of the battery block in a state where the voltage change amount (dV / dt) is small.

  Further, overdischarge of the battery block can be determined from a voltage deviation between the average voltage of all the battery blocks and the voltage of each battery block. However, this device is also difficult to reliably determine overdischarge of the battery block. Hereinafter, the reason will be described in detail with reference to FIG. This figure is a graph showing the voltage change of each battery block to be discharged. In this graph, the voltage change of the overdischarge block is indicated by a chain line A, the voltage change of the battery block is normally indicated by a solid line, and the change of the average voltage of all the battery blocks is indicated by a bold line. In this graph, an alternate long and short dash line B indicates a difference voltage between the average voltage of the battery block and the voltage of the overdischarge block, that is, a voltage deviation (= voltage difference). In the battery block shown in this graph, the voltage deviation of the overdischarge block is only 0.1V. That is, it is necessary to detect overdischarge of the battery block from a voltage deviation of 0.1V. As described above, when overdischarge is detected from a very small voltage deviation, it is difficult to accurately determine overdischarge, and it is necessary to increase the accuracy of parts constituting the determination circuit, resulting in high manufacturing costs. .

  The present invention has been developed for the purpose of solving such drawbacks. An important object of the present invention is to reliably detect battery block overdischarge with high accuracy without increasing the accuracy of parts for detecting the overdischarge block, and effectively prevent overdischarge of the battery block. An object of the present invention is to provide a power supply device for a vehicle that can extend the service life of the vehicle.

  The vehicle power supply device of the present invention has the following configuration in order to achieve the above-described object. The power supply device includes a battery 1 including a plurality of battery blocks, and a determination device 2 that detects a battery block in an overdischarged state. The discriminating apparatus 2 includes a voltage detection circuit 4 that detects the voltage of each battery block, and an overdischarge determination that detects a battery block in an overdischarge state from the voltage of each battery block detected by the voltage detection circuit 4. Circuit 4.

  The overdischarge determination circuit 4 detects a reference voltage change amount (dV / dt) in a unit time of all battery blocks, and detects a module voltage change amount (dVn / dt) in a specific time of each battery block. The voltage change integrated value (Σ {dV / dt−dVn / dt}) is calculated by integrating the difference between the voltage change amount (dV / dt) and the module voltage change amount (dVn / dt), and this voltage change integrated value is calculated. The battery block overdischarge is determined from (Σ {dV / dt−dVn / dt}).

  In the power supply device according to claim 2 of the present invention, the overdischarge determination circuit 4 uses the average voltage change amount per unit time of the average value of the voltages of all battery blocks (dV / dt) dVave / dt) is calculated. This power supply device can definitely detect the overdischarge battery block of the battery block.

  In the power supply device according to claim 3 of the present invention, the overdischarge determination circuit 4 uses the maximum voltage change amount per unit time of the maximum value of the voltage of all battery blocks as the reference voltage change amount (dV / dt) of all battery blocks. dVmax / dt) is calculated. In this power supply device, since the voltage change integral value (Σ {dV / dt−dVn / dt}) of the battery block becomes large, overdischarge of the battery block can be detected quickly.

  Furthermore, in the power supply device according to claim 4 of the present invention, the overdischarge determination circuit 4 is between the maximum value and the minimum value of the voltage of all the battery blocks as the reference voltage change amount (dV / dt) of all the battery blocks. An intermediate voltage change amount (dVmed / dt) per unit time of the intermediate voltage is calculated.

  In the power supply device according to claim 5 of the present invention, the overdischarge determination circuit 4 compares the voltage change integral value (Σ {dV / dt−dVn / dt}) with the threshold value a plurality of times, and the overdischarge of the battery block is performed. Determine. This power supply device can detect overdischarge of the battery block while preventing erroneous detection.

  In the power supply device according to claim 6 of the present invention, the overdischarge determination circuit 4 compares the voltage change integral value (Σ {dV / dt−dVn / dt}) with different threshold values in the charge state and the discharge state. Then, overdischarge of the battery block is determined. This power supply apparatus can discriminate the battery block that is overdischarged in both the state where the battery is charged or discharged.

  In the power supply device according to claim 7 of the present invention, the determination device compares the voltage change integral value with the threshold only in the battery block in which the voltage increases in the charged state or decreases in the discharged state. A faulty battery block can be identified, and overdischarge of a normally operating battery block can be detected.

  Furthermore, the power supply device according to claim 8 of the present invention includes a temperature detection circuit 6 in which the discrimination device detects the temperature of the battery module, and the overdischarge determination circuit 4 stores a threshold value that varies depending on the temperature of the battery module. The calculated voltage change integral value (Σ {dV / dt−dVn / dt}) is compared with a threshold value to detect overdischarge of the battery block. This power supply device can more accurately determine overdischarge of the battery block whose temperature changes.

  The power supply device of the present invention has a feature that can reliably detect overdischarge of the battery block with high accuracy. The determination device equipped in the power supply device of the present invention detects the voltage of each battery block by the voltage detection circuit, and the reference voltage change in the unit time of all the battery blocks from the detected voltage of each battery block. The amount (dV / dt) and the module voltage change amount (dVn / dt) at a specific time of each battery block are detected, the difference between the reference voltage change amount and the module voltage change amount is integrated, and the voltage change integrated value ( This is because Σ {dV / dt−dVn / dt}) is calculated, and overdischarge of the battery block is determined from this voltage change integral value (Σ {dV / dt−dVn / dt}).

  It is apparent from FIGS. 1 and 4 that the power supply device of the present invention can accurately detect overdischarge of the battery block. 1 indicates a voltage deviation between the voltage of the overdischarge battery module and the average voltage (dVave) of all the battery modules. As is clear from this figure, the voltage deviation between the battery modules and all the battery modules is small, and it is difficult to accurately determine overdischarge of the battery module from this voltage deviation. The power supply apparatus of the present invention determines overdischarge of the battery module in the battery block from the voltage change integral value (Σ {dV / dt−dVn / dt}) indicated by the one-dot chain line C in FIG. The voltage change integral value (Σ {dV / dt−dVn / dt}) is a value obtained by integrating the difference between the reference voltage change amount (dV / dt) and the module voltage change amount (dVn / dt) with time. The voltage change integral value (Σ {dV / dt−dVn / dt}) of the overdischarged battery module gradually increases as time passes, as shown by a dashed line C in the figure, for example, 2.4 msec. The subsequent voltage change integral value (Σ {dV / dt−dVn / dt}) is twice as large as the voltage deviation indicated by the one-dot chain line B in FIG.

  As described above, the power supply device of the present invention discriminates overdischarge of the battery block from the voltage change integral value that becomes large in the overdischarged battery block, so that the component accuracy that constitutes the discrimination device reliably and accurately A feature that can be detected without increasing the value is realized. In addition, since overdischarge of the battery block can be detected accurately and promptly, the battery can be charged and discharged while effectively preventing overdischarge of the battery, thereby realizing a feature that can extend the life of the battery.

  Embodiments of the present invention will be described below with reference to the drawings. However, the following embodiment exemplifies a power supply device for a vehicle for embodying the technical idea of the present invention, and the present invention does not specify the power supply device as follows.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  2 includes a traveling battery 1 including a plurality of battery blocks M1, M2,... Mn, and a determination device 2 that detects overdischarge of the battery block. The discrimination device 2 includes a voltage detection circuit 3 that detects battery voltage in units of battery blocks M1, M2,... Mn, and the voltage of each battery module detected by the voltage detection circuit 3, that is, the battery block When the overdischarge determination circuit 4 that detects an overdischarged battery block from the voltage and the overdischarge determination circuit 4 determines that a specific battery block is overdischarged, this is controlled to charge / discharge the battery 1 for traveling. And an interface circuit 5 for outputting to a battery electronic control device (not shown).

  Furthermore, the discrimination device 2 of the power supply device includes a temperature detection circuit 6 that detects the temperature of the battery module, and a current detection circuit 7 that detects a charge / discharge current. The overdischarge determination circuit 4 calculates the maximum current that can be charged / discharged from the battery module temperature signal input from the temperature detection circuit 6 and the battery module charge / discharge current input from the current detection circuit 7. The maximum current is output to the vehicle battery control device via the interface circuit 5.

  In the battery 1 for traveling, a plurality of unit cells are connected in series to form a battery module, and the plurality of battery modules are connected in series to increase the output voltage. In the power supply apparatus, one voltage module is used as one battery block, or a plurality of battery modules bonded in series as one battery block, and the voltage detection circuit 3 detects the voltage. Since the power supply device that uses one battery module as one battery block uses the battery module as the battery block, the voltage of the battery block becomes the voltage of the battery module. Therefore, in this power supply device, the battery module and the battery block are synonymous. Hereinafter, the Example which uses a battery block as a battery module is explained in full detail.

  The battery 1 for traveling has 50 battery modules connected in series. However, the number of batteries for traveling may be less than 50, or more than 50 battery modules may be connected in series. A power supply device that uses one battery module as one battery block detects the voltage of each battery module by the voltage detection circuit 3 of the determination device 2. Each battery module has five nickel metal hydride batteries connected in series. The traveling battery 1 in which 50 battery modules are connected in series has a total of 250 nickel-metal hydride batteries connected in series to an output voltage of 300V. The battery module does not necessarily connect five batteries in series. For example, four or less, or six or more secondary batteries can be connected in series. Further, the battery module may be a single secondary battery. Further, as the secondary battery, any other rechargeable battery such as a lithium ion secondary battery or a nickel cadmium battery can be used.

  The discriminating device 2 includes a voltage detection circuit 3 that detects the voltage of each battery module, and an overdischarge determination that determines overdischarge of the battery module, in other words, overdischarge of the battery block, from the voltage detected by the voltage detection circuit 3. A circuit 4 is provided. A state in which the determination device 2 determines overdischarge of the battery block will be described with reference to FIGS. 3 and 4. FIG. 3 is a graph showing a state in which the voltage of each battery module decreases as it is discharged. This figure shows the average voltage (Vave) of all the battery modules and the voltage change of the test symmetrical battery module that is overdischarged in the right figure. As shown in this figure, the voltage of the inspection symmetrical battery module that is overdischarged rapidly decreases as it is discharged.

  As shown in FIGS. 3 and 4, in order to detect the voltage of each battery module, the voltage detection circuit 3 of the determination device 2 detects the voltage of each battery module at a constant sampling period. The voltage detection circuit 3 switches the multiplexer provided on the input side and detects the voltage of each battery module in turn. The sampling period for detecting the voltage of the battery modules in order is, for example, 1 msec to 100 msec. The voltage of the battery module detected by the voltage detection circuit 3 is input to the overdischarge determination circuit 4. The voltage of the battery module is converted into a digital signal by an A / D converter (not shown) built in the voltage detection circuit 3 and input to the overdischarge determination circuit 4. The overdischarge determination circuit 4 detects the reference voltage change amount (dV / dt) per unit time of all the battery blocks from the input voltage change of each battery module.

  The reference voltage change amount (dV / dt) is preferably an average voltage change amount (dVave / dt) in a unit time of an average value of voltages of all battery blocks. However, the reference voltage change amount (dV / dt) may be the maximum voltage change amount (dVmax / dt) per unit time of the maximum value of the voltage of all the battery blocks. Further, the reference voltage change amount (dV / dt) may be an intermediate voltage change amount (dVmed / dt) in a unit time of an intermediate voltage between the highest value and the lowest value of the voltages of all the battery blocks. The intermediate voltage change amount (dVmed / dt) is calculated, for example, by multiplying the average voltage change amount (dVave / dt) by a specific coefficient, or the average voltage change amount (dVave / dt) and the maximum voltage change amount (dVmax / dt). ) Are averaged, or alternatively, the maximum voltage change amount (dVmax / dt) is multiplied by a coefficient of 1 or less.

  The overdischarge determination circuit 4 of the determination device 2 further detects a module voltage change amount (dVn / dt), which is a change amount per unit time of each battery module. Further, the overdischarge determination circuit 4 integrates a difference between the reference voltage change amount (dV / dt) and the module voltage change amount (dVn / dt) to obtain a voltage change integrated value (Σ {dV / dt−dVn / dt}). ) Is detected.

  An apparatus that uses the reference voltage change amount (dV / dt) as the average voltage change amount (dVave / dt) integrates the difference between the average voltage change amount (dVave / dt) and the module voltage change amount (dVn / dt), A voltage change integral value (Σ {dVave / dt−dVn / dt}) is detected. An apparatus that uses the reference voltage change amount (dV / dt) as the maximum voltage change amount (dVmax / dt) integrates the difference between the maximum voltage change amount (dVmax / dt) and the module voltage change amount (dVn / dt), A voltage change integral value (Σ {dVmax / dt−dVn / dt}) is detected.

  The overdischarge determination circuit 4 compares the calculated voltage change integration value (Σ {dV / dt−dVn / dt}) with a threshold value stored in advance in a memory (not shown), and calculates the voltage change integration value. A battery module having a value (Σ {dV / dt−dVn / dt}) greater than a threshold value is determined as overdischarge.

Flow charts for determining the overdischarge of the battery module by the determination device 2 are shown in FIGS.
As shown in the flowchart of FIG. 5, the determination device 2 determines overdischarge of the battery module in the following steps.
[Step of n = 1]
The voltage detection circuit 3 detects the voltage (V1 to Vn) of the battery module at a predetermined sampling period.
[Step of n = 2]
The overdischarge determination circuit 4 detects the average voltage (Vave) of all the battery modules from each detected battery module.
[Steps n = 3, 4]
The overdischarge determination circuit 4 detects and calculates an average voltage change amount (dVave / dt) at which the average voltage of the battery module changes per unit time as a reference voltage change amount (dV / dt).
A time change amount (dVn / dt) of each battery module voltage Vn is detected and calculated.
[Steps n = 5, 6]
For each battery module, the time change amount (dVn / dt) of the battery module voltage Vn is subtracted from the average voltage change amount (dVave / dt), which is the detected reference voltage change amount (dV / dt). The battery module in which the difference value is compared with the threshold value 1 and is determined to be equal to or less than the threshold value 1 is overdischarged as a variation amount between the battery modules or a measurement error. If not, it loops to a step of n = 1. Since n is not overdischarge at n = 6, the integrated value (= added value) of the difference is set to zero. The threshold value 1 is stored in advance in the memory of the overdischarge determination circuit 4.
[Step n = 7]
The overdischarge determination circuit 4 determines that the average voltage change amount (dVave / dt) of the reference voltage change amount (dV / dt) is not smaller than the threshold value 1, in other words, large (considered as a state immediately before overdischarge). The voltage change integral value (Σ {dVave / dt−dVn / dt}) of the battery module is calculated.
[Step n = 8]
The overdischarge determination circuit 4 compares the voltage change integral value (Σ {dVave / dt−dVn / dt}) with the threshold value 2. The threshold value 2 is stored in the memory of the overdischarge determination circuit 4.
[Steps n = 9 to 11]
The overdischarge determination circuit 4 determines that the battery module that determines that the voltage change integral value (Σ {dVave / dt−dVn / dt}) is greater than the threshold 2 is overdischarge. When it is determined that the battery module is over-discharged, this information is transmitted to the vehicle battery control device via the interface circuit 5. Return to n = 1.
The battery module determined that the voltage change integral value (Σ {dVave / dt−dVn / dt}) is not larger than the threshold value 2 is determined not to be overdischarged. Return to n = 1.

The above discriminating device 2 determines overdischarge of the battery module using the reference voltage change amount (dV / dt) as the average voltage change amount (dVave / dt). The determination device 2 can detect overdischarge of the battery module with the reference voltage change amount (dV / dt) as the maximum voltage change amount (dVmax / dt). As shown in the flowchart of FIG. 6, the determination device 2 determines overdischarge of the battery module in the following steps.
[Step of n = 1]
The voltage detection circuit 3 detects the voltage (V1 to Vn) of the battery module at a predetermined sampling period.
[Step of n = 2]
The overdischarge determination circuit 4 detects the maximum voltage (Vmax) of all the battery modules from each detected battery module.
[Steps n = 3, 4]
The overdischarge determination circuit 4 detects and calculates the maximum voltage change amount (dVmax / dt) at which the average voltage of the battery module changes per unit time as the reference voltage change amount (dV / dt).
A time change amount (dVn / dt) of each battery module voltage Vn is detected and calculated.
[Steps n = 5, 6]
For each battery module, the time variation (dVn / dt) of the battery module voltage Vn is subtracted from the maximum voltage variation (dVmax / dt), which is the detected reference voltage variation (dV / dt). The battery module in which the difference value is compared with the threshold value 3 and is determined to be equal to or less than the threshold value 3 is overdischarged as a variation amount between the battery modules or a measurement error. If not, it loops to a step of n = 1. Since n is not overdischarge at n = 6, the integrated value (= added value) of the difference is set to zero. The threshold value 3 is stored in advance in the memory of the overdischarge determination circuit 4.
[Step n = 7]
The overdischarge determination circuit 4 determines that the maximum voltage change amount (dVmax / dt) of the reference voltage change amount (dV / dt) is not smaller than the threshold value 3, in other words, is large (considered as a state immediately before overdischarge). The voltage change integral value (Σ {dVmax / dt−dVn / dt}) of the battery module is calculated.
[Step n = 8]
The overdischarge determination circuit 4 compares the voltage change integral value (Σ {dVmax / dt−dVn / dt}) with the threshold value 4. The threshold value 4 is stored in the memory of the overdischarge determination circuit 4.
[Steps n = 9 to 11]
The overdischarge determination circuit 4 determines that the battery module that determines that the voltage change integral value (Σ {dVmax / dt−dVn / dt}) is greater than the threshold value 4 is overdischarge. When it is determined that the battery module is over-discharged, this information is transmitted to the vehicle battery control device via the interface circuit 5. Return to n = 1.
The battery module determined that the voltage change integral value (Σ {dVmax / dt−dVn / dt}) is not larger than the threshold value 4 is determined not to be overdischarged. Return to n = 1.

  As shown in FIG. 7, the discriminating apparatus 2 uses the calculated voltage change integral value (Σ {dV / dt−dVn / dt}) in the step of n = 8 in FIG. 5 or FIG. In comparison with this, it is possible to determine overdischarge of the battery module. As shown in the flowchart of FIG. 7, the determination device 2 thresholds the voltage change integral value (Σ {dV / dt−dVn / dt}) three times following the step of n = 8 in FIG. 5 or 6. The overdischarge of the battery module is determined in the step of n = 8 ′ compared with the value 5. This discrimination device 2 can detect the overdischarge of the battery module more reliably.

  As shown in the flowchart of FIG. 8, the discriminating device 2 identifies charging and discharging of the battery module, and calculates different voltage change integral values (Σ {dV / dt−dVn / dt}) for charging and discharging. Thus, overdischarge of the battery module can also be determined. This flowchart determines overdischarge of the battery module in the following steps.

[Steps n = 1-7]
This step is the same as in FIG. 5 or FIG.
[Step n = 8]
In this step, charging and discharging of the battery module are determined. The charging and discharging of the battery module can be determined based on whether a charging current is flowing or a discharging current is flowing.
[N = 9, 10 steps]
When the battery module is charged, the voltage change integral value (Σ {dVmax / dt−dVn / dt}) is compared with the threshold value 6, and the voltage change integral value (Σ {dVmax / dt−dVn / dt}) is compared to threshold value 7. The threshold 6 is a value for determining overdischarge of the battery module being charged, and the threshold 7 is a value for determining overdischarge of the battery module being discharged, in the memory of the overdischarge determination circuit 4. It is memorized beforehand.
[Steps n = 11-13]
The overdischarge determination circuit 4 determines that the battery module is overdischarged when the voltage change integral value (Σ {dVmax / dt−dVn / dt}) of the battery module being charged is larger than the threshold value 6. When it is determined that the battery module is over-discharged, this information is transmitted to the vehicle battery control device via the interface circuit 5.
The overdischarge determination circuit 4 determines that the battery module is overdischarged when the voltage change integral value (Σ {dVmax / dt−dVn / dt}) of the discharged battery module is larger than the threshold value 7. And transmitted to the battery control device of the vehicle via the interface circuit 5.
The overdischarge determination circuit 4 has a voltage change integral value (Σ {dVmax / dt−dVn / dt}) of the battery module being charged not greater than the threshold value 6 or a voltage change of the battery module being discharged. If the integral value (Σ {dVmax / dt−dVn / dt}) is not larger than the threshold value 7, it is determined that there is no overdischarge.

  The above discriminating device 2 discriminates overdischarge of the battery module using the reference voltage change amount (dV / dt) as the maximum voltage change amount (dVmax / dt), but uses the reference voltage change amount (dV / dt) as the average voltage. The overdischarge of the battery module can also be determined as the amount of change (dVave / dt).

  In the flowchart of FIG. 9, the overdischarge determination circuit 4 of the determination device 2 compares the voltage change integral value with the threshold value only for the battery block whose voltage increases in the charged state or decreases in the discharged state. To determine if the battery module is over-discharged. According to this flowchart, a battery module whose voltage drops despite being charged or a battery module whose voltage rises despite being discharged is excluded from overdischarge discrimination symmetry as an abnormal battery module. . This discrimination device detects the voltage of each battery module, further identifies the charge / discharge of the battery module, and the voltage of the charging battery module increases or the voltage of the discharging battery module decreases. After determining whether or not the battery module is overdischarged, the determination is started.

In the flowchart of FIG. 10, the threshold value for comparing the voltage change integral value (Σ {dV / dt−dVn / dt}) is changed according to the temperature of the battery module. This discrimination device detects overdischarge of the battery module in the following flowchart.
[Steps n = 1-7]
This step is the same as in FIG. 5 or FIG.
[Step n = 8]
In this step, the overdischarge determination circuit 4 obtains the threshold value 8 from the battery module. The overdischarge determination circuit 4 stores a function for specifying the threshold value 8 from the temperature in a memory, or stores a table for specifying the threshold value 8 from the temperature.
[Step n = 9]
The overdischarge determination circuit 4 compares the voltage change integral value (Σ {dVmax / dt−dVn / dt}) with the threshold value 8.
[Steps n = 10-12]
The overdischarge determination circuit 4 determines that the battery module is overdischarged when the voltage change integral value (Σ {dVmax / dt−dVn / dt}) of the battery module is larger than the threshold value 8. When it is determined that the battery module is over-discharged, this information is transmitted to the vehicle battery control device via the interface circuit 5.
If the voltage change integral value (Σ {dVmax / dt−dVn / dt}) of the battery module is not larger than the threshold value 8, the overdischarge determination circuit 4 determines that there is no overdischarge.

  The above discriminating device 2 discriminates overdischarge of the battery module using the reference voltage change amount (dV / dt) as the maximum voltage change amount (dVmax / dt), but uses the reference voltage change amount (dV / dt) as the average voltage. The overdischarge of the battery module can also be determined as the amount of change (dVave / dt).

It is a graph which shows the voltage change of a some battery module. It is a block diagram of the power supply device for vehicles concerning one example of the present invention. It is a graph which shows the state from which the voltage of a some battery module changes. It is a graph which shows the state in which the power supply device of this invention detects the overdischarge of a battery block from voltage change integral value ((SIGMA) {dV / dt-dVn / dt}). It is a flowchart in which the power supply device of the Example of this invention discriminate | determines a battery block. It is a flowchart in which the power supply device of the Example of this invention discriminate | determines a battery block. It is a flowchart in which the power supply device of the Example of this invention discriminate | determines a battery block. It is a flowchart in which the power supply device of the Example of this invention discriminate | determines a battery block. It is a flowchart in which the power supply device of the Example of this invention discriminate | determines a battery block. It is a flowchart in which the power supply device of the Example of this invention discriminate | determines a battery block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery 2 ... Discriminating device 3 ... Voltage detection circuit 4 ... Overdischarge determination circuit 5 ... Interface circuit 6 ... Temperature detection circuit 7 ... Current detection circuit

Claims (8)

A power supply device for a vehicle comprising a battery (1) comprising a plurality of battery blocks, and a determination device (2) for detecting a battery block in an overdischarge state,
The discrimination device (2) detects the voltage of each battery block from the voltage detection circuit (3) and the voltage of each battery block detected by the voltage detection circuit (3). The reference voltage change amount (dV / dt) is detected, and the module voltage change amount (dVn / dt) at a specific time of each battery block is detected. The reference voltage change amount (dV / dt) and the module voltage change amount ( dVn / dt) is integrated to calculate a voltage change integral value (Σ {dV / dt−dVn / dt}), and from this voltage change integral value (Σ {dV / dt−dVn / dt}) A vehicle power supply apparatus comprising an overdischarge determination circuit (4) for determining overdischarge of a block.   The overdischarge determination circuit (4) calculates an average voltage change amount (dVave / dt) per unit time of an average value of voltages of all battery blocks as a reference voltage change amount (dV / dt) of all battery blocks. 1. A power supply device for a vehicle according to 1.   The overdischarge determination circuit (4) calculates, as a reference voltage change amount (dV / dt) of all battery blocks, a maximum voltage change amount (dVmax / dt) per unit time of a maximum value of the voltage of all battery blocks. 1. A power supply device for a vehicle according to 1.   The overdischarge determination circuit (4) determines the amount of change in the intermediate voltage per unit time of the intermediate voltage between the highest value and the lowest value of the voltage of all the battery blocks as the reference voltage change amount (dV / dt) of all the battery blocks. The power supply device for vehicles according to claim 1 which calculates dVmed / dt).   The overdischarge determination circuit (4) is configured to determine overdischarge of a battery block by comparing a voltage change integral value (Σ {dV / dt-dVn / dt}) with a threshold value a plurality of times. A power supply device for a vehicle.   The overdischarge determination circuit (4) compares the voltage change integral value (Σ {dV / dt−dVn / dt}) with different threshold values in the charge state and the discharge state to determine overdischarge of the battery block. The power supply device for vehicles according to claim 1.   2. The vehicle-use vehicle according to claim 1, wherein the discriminating device (2) compares the voltage change integral value with a threshold value only for a battery block whose voltage rises in a charged state or drops in a discharged state. Power supply. The discrimination device (2) includes a temperature detection circuit (6) that detects the temperature of the battery block, and the overdischarge determination circuit (4) stores a threshold value that varies depending on the temperature of the battery block, and is calculated. 2. The vehicle power supply device according to claim 1, wherein overdischarge of the battery block is detected by comparing a voltage change integral value (Σ {dV / dt−dVn / dt}) with a threshold value.

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