JP2021018969A - Management device and electrical power system - Google Patents

Abstract

To enhance a temperature monitoring of a plurality of cells connected in serial, while suppressing a cost.SOLUTION: A voltage measurement circuit (30) is connected to each node of a plurality of cells (E1-E3) with a voltage measurement wire (L1-L4) to measure each voltage of the plurality of cells (E1-E3). A plurality of discharge circuits (Rd1-Rd3 and Q1-Q3) is connected to each of two adjacent voltage measurement wires and each of the plurality of cells (E1-E3) in parallel. A control circuit (40) executes an equivalent processing between the plurality of cells (E1-E3). A temperature transducer (T1) is connected between a node of an insertion resistor (Rdv1) on the voltage measurement wire (L1) at the voltage measurement circuit (30) side and a node between the discharge resistor (Rd1) connected to the voltage measurement wire (L1) and a switch (Q1). The control circuit (40) estimates a circumference temperature of the temperature transducer (T1) on the basis of a voltage measured in an on state of the switch (Q1).SELECTED DRAWING: Figure 1

Description

The present invention relates to a management device and a power supply system that manage the states of a plurality of cells connected in series.

In recent years, hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), and electric vehicles (EVs) have become widespread. These electric vehicles are equipped with a secondary battery as a key device. Nickel-metal hydride batteries and lithium-ion batteries are mainly used as in-vehicle secondary batteries. It is expected that the spread of lithium-ion batteries with high energy density will accelerate in the future.

Normally, in an in-vehicle secondary battery, the voltage, temperature, and current of the battery are constantly monitored from the viewpoint of ensuring safety. In particular, a lithium ion battery requires strict voltage control because the normal area and the prohibited area are close to each other, and the voltage is measured in cell units (see, for example, Patent Document 1). In the lithium ion battery, from the viewpoint of maintaining power efficiency and ensuring safety, an equalization process for equalizing the capacities among a plurality of cells connected in series is executed. The passive method is the mainstream as the equalization processing method. In the passive method, a discharge resistor is connected to each of a plurality of cells connected in series, and the other cell is discharged so as to match the capacity of the other cell with the capacity of the cell having the lowest capacity.

Generally, the temperature of an in-vehicle secondary battery is measured using a thermistor. Normally, one thermistor is not installed for each cell, but one for each of a plurality of cells. Installing thermistors in all cells increases costs and complicates wiring. Specifically, it is necessary to increase the number of thermistors, the number of harnesses and connectors connecting the thermistors and the measurement circuit, and the number of A / D converters and multiplexers in the measurement circuit, which increases the overall cost. Wiring between the battery and the management device is also complicated.

Japanese Unexamined Patent Publication No. 2013-68533

In recent years, the cells have tended to become larger in size with the need for capacity increase, and the calorific value of the cells has tended to increase. From the viewpoint of safety, it is desirable to monitor the temperature for each cell.

The present disclosure has been made in view of these circumstances, and an object of the present invention is to provide a technique for enhancing temperature monitoring of a plurality of cells connected in series while keeping costs down.

In order to solve the above problems, the management device of a certain aspect of the present disclosure is connected to each node of a plurality of cells connected in series by a voltage measurement line, and is a voltage measurement circuit that measures the voltage of each of the plurality of cells. And, a plurality of discharge circuits connected in parallel to the plurality of cells, respectively, between two adjacent voltage measurement lines, and the voltage measurement from a node with the discharge circuit on the plurality of voltage measurement lines. By controlling the plurality of discharge circuits based on the plurality of insertion resistances inserted into the circuit side and the voltages of the plurality of cells measured by the voltage measurement circuit, equalization among the plurality of cells is performed. It is provided with a control circuit for executing the conversion process. Each of the plurality of discharge circuits includes a discharge resistor and a switch connected in series. The management device further includes at least one temperature sensitive element whose resistance value changes depending on the temperature. The temperature sensitive element is connected between a node on the voltage measurement line of the insertion resistor on the voltage measurement circuit side and a node between the discharge resistor connected to the voltage measurement line and the switch, and controls the control. The circuit estimates the ambient temperature of the temperature sensitive element based on the voltage measured by the voltage measuring circuit in the on state of the switch.

According to the present disclosure, temperature monitoring of a plurality of cells connected in series can be enhanced while keeping costs down.

It is a figure which shows the structure of the power-source system which concerns on Embodiment 1. FIG. It is a partial circuit diagram which shows the basic unit structure of the power-source system which concerns on Embodiment 1. FIG. It is a partial circuit diagram which shows the basic unit structure of the power-source system which concerns on a comparative example. It is a figure which shows the structure of the power-source system which concerns on Embodiment 2. FIG. 5 is a partial circuit diagram showing a basic configuration for two cells of the power supply system according to the first embodiment. FIG. 5 is a partial circuit diagram showing a basic configuration for two cells of the power supply system according to the second embodiment.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a power supply system 1 according to the first embodiment. The power supply system 1 is mounted on an electric vehicle and used as a drive battery for the electric vehicle. The power supply system 1 includes a power storage module 10 and a management device 20. The power storage module 10 includes a plurality of cells E1-E3 connected in series. As the cell, a lithium ion battery cell, a nickel hydrogen battery cell, a lead battery cell, an electric double layer capacitor cell, a lithium ion capacitor cell, or the like can be used. Hereinafter, in the present specification, an example in which a lithium ion battery cell (nominal voltage: 3.6-3.7 V) is used is assumed.

In FIG. 1, for simplification, the power storage module 10 in which three cells E1-E3 are connected in series is drawn, but the actual configuration has more cells depending on the voltage specifications required for the power supply system 1. Are connected in series. In addition, a plurality of cells may be connected in series and parallel to increase the capacity.

The management device 20 includes a plurality of discharge circuits, a voltage measurement circuit 30, and a control circuit 40. Each node of the plurality of cells E1-E3 connected in series and the voltage measuring circuit 30 are connected by a plurality of voltage measuring lines L1-L4.

The plurality of discharge circuits are connected in parallel with the plurality of cells E1-E3, respectively, between two adjacent voltage measurement lines. The first discharge circuit is composed of a first discharge resistor Rd1 and a first external discharge switch Q1 connected in series, and is parallel to the first cell E1 between the first voltage measurement line L1 and the second voltage measurement line L2. Be connected. The second discharge circuit and the third discharge circuit are configured in the same manner as the first discharge circuit.

A semiconductor switch can be used for the external discharge switches Q1-Q3. In the example shown in FIG. 1, an N-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used.

In the input stage of the voltage measurement circuit 30, input resistors Rf1-Rf4 are inserted into each of the plurality of voltage measurement lines L1-L4. Further, in the input stage of the voltage measurement circuit 30, input capacitances Cf1-Cf3 are connected to each of two adjacent voltage measurement lines. The input resistor Rf1-Rf4 and the input capacitance Cf1-Cf3 form a low-pass filter and suppress aliasing.

The voltage measuring circuit 30 measures the voltage of each cell E1-E3 by measuring the voltage between two adjacent voltage measuring lines. In the present embodiment, the voltage measurement circuit 30 is composed of an ASIC (Application Specific Integrated Circuit) which is a dedicated custom IC. The voltage measurement circuit 30 includes a multiplexer (not shown), an A / D converter, and a communication circuit (not shown).

The multiplexer outputs the voltages input to the input channels of the plurality of cells E1-E3 to the AD converter in a predetermined order. The A / D converter samples the analog voltage input from the multiplexer at a predetermined timing, and converts the sampled analog voltage into a digital value. The communication circuit transmits the voltage values of the plurality of cells E1-E3 converted into digital values by the A / D converter to the control circuit 40. Since the voltage measurement circuit 30 has a higher voltage than the control circuit 40, the voltage measurement circuit 30 and the control circuit 40 are connected by a communication line in an insulated state. It should be noted that the design may be such that the A / D converter is provided for each input channel without providing the multiplexer in the ASIC.

The voltage measuring circuit 30 further includes a plurality of internal discharge switches S1-S3. The plurality of internal discharge switches S1-S3 are internal switches for controlling the on / off of the plurality of external discharge switches Q1-Q3, respectively. A semiconductor switch can be used for the plurality of internal discharge switches S1-S3.

The first internal discharge switch S1 is connected between the first gate signal line G1 and the second gate signal line G2. A voltage on the positive electrode side of the first cell E1 is applied to the first gate signal line G1 via a parallel circuit of the Zener diode ZD1 and the resistor R1a and the resistor R1b. A voltage on the negative electrode side of the first cell E1 (positive electrode side of the second cell E2) is applied to the second gate signal line G2 via a parallel circuit of the Zener diode ZD2 and the resistor R2a and the resistor R2b.

The gate terminal of the first external discharge switch Q1 is connected to the voltage dividing points of the resistors R2a and R2b. The source terminal of the first external discharge switch Q1 is connected to the negative electrode of the first cell E1. When the first internal discharge switch S1 is on, the gate-source voltage of the first external discharge switch Q1 becomes equal to or higher than the threshold voltage, and the first external discharge switch Q1 is also turned on. In this state, a discharge current flows from the first cell E1 to the first discharge resistor Rd1, and the capacity of the first cell E1 decreases. On the other hand, in the off state of the first internal discharge switch S1, the gate-source voltage of the first external discharge switch Q1 becomes less than the threshold voltage, and the first external discharge switch Q1 is also in the off state. In this state, no discharge current flows from the first cell E1 to the first discharge resistor Rd1, and the capacity of the first cell E1 is maintained.

Discharge from the second cell E2 and discharge from the third cell E3 are also performed by on / off control of the second internal discharge switch S2 and the third internal discharge switch S3 in the same manner as the discharge from the first cell E1. Can be done.

In the input stage of the voltage measurement circuit 30, input capacitances C1-C3 are connected to each of two adjacent gate signal lines. In the present embodiment, the voltage measuring circuit 30 has a function of measuring the voltage across each of the plurality of internal discharge switches S1-S3. The voltage measuring circuit 30 can measure the voltage across the first internal discharge switch S1 and detect the voltage of the first cell E1 in the off state of the first internal discharge switch S1.

The control circuit 40 acquires the voltage, temperature, and current of the plurality of cells E1-E3 included in the power storage module 10 and manages the plurality of cells E1-E3. In the present embodiment, the control circuit 40 is composed of a microcomputer and a non-volatile memory (for example, EEPROM, flash memory) (not shown).

The control circuit 40 executes equalization processing among the plurality of cells E1-E3 based on the voltage values of the plurality of cells E1-E3 received from the voltage measurement circuit 30. In the general passive cell balance method, the other cells are discharged to the capacity of the cell having the smallest capacity among the plurality of cells E1-E3 (hereinafter referred to as a target value). The target value may be defined by any of the actual capacity, SOC (State Of Charge), and OCV (Open Circuit Voltage). When specified by OCV, the OCV of the cell with the lowest OCV is the target value. The target value may be defined by the dischargeable amount or the rechargeable amount.

The control circuit 40 sets the measured value of the cell having the smallest capacity among the plurality of cells E1-E3 as the target value, and calculates the difference between the target value and the measured values of the other plurality of cells. The control circuit 40 calculates the discharge amount of the other plurality of cells based on the calculated difference, and calculates the discharge time of the other plurality of cells based on the calculated discharge amount. To do. The control circuit 40 generates a control signal for equalization processing including discharge times of a plurality of cells, and transmits the control signal to the voltage measurement circuit 30. The voltage measurement circuit 30 controls the plurality of internal discharge switches S1-S3 in the ON state for a designated time, respectively, based on the control signal received from the control circuit 40.

In FIG. 1, voltage dividing resistors Rdv1-Rdv3 are inserted into the voltage measuring circuit 30 side from the node with the discharging circuit on the plurality of voltage measuring lines L1-L4, respectively. The first thermistor T1 is located between the node on the voltage measuring circuit 30 side of the first voltage dividing resistor Rdv1 on the first voltage measuring line L1 and the node between the first discharge resistor Rd1 and the first external discharge switch Q1. Connected to. The second thermistor T2 and the third thermistor T3 are also connected in the same manner as the first thermistor T1.

Thermistors T1-T3 are temperature-sensitive elements whose resistance value changes according to the ambient temperature. As the temperature sensitive element, an NTC (Negative Temperature Coefficient) thermistor, a PTC (Ppositive Temperature Coefficient) thermistor, a CTR (Critical Temperature Resistor) thermistor, a platinum resistance temperature detector, or the like can be used. Hereinafter, in the present embodiment, an example in which a chip-type NTC thermistor is used is assumed.

The first thermistor T1 is installed in the vicinity of the first cell E1, and the first thermistor T1 and the first cell E1 are thermally coupled. The first cell E1 is affected by heat dissipation from the management device 20 (particularly heat dissipation from the first discharge resistor Rd1) as well as heat generation due to the current flowing through itself. Similarly, the second thermistor T2 is installed in the vicinity of the second cell E2, and the second thermistor T2 and the second cell E2 are thermally coupled. Similarly, the third thermistor T3 is installed in the vicinity of the third cell E3, and the third thermistor T3 and the third cell E3 are thermally coupled.

When the first external discharge switch Q1 is on, the voltage measuring circuit 30 measures the voltage of the first voltage dividing resistor Rdv1 and the voltage dividing point Nd1 of the first thermistor T1. The control circuit 40 estimates the temperature of the first cell E1 based on the voltage measured by the voltage measuring circuit 30 in the ON state of the first external discharge switch Q1. The control circuit 40 detects the voltage of the first cell E1 based on the voltage measured by the voltage measuring circuit 30 in the off state of the first external discharge switch Q1.

The voltage across the first voltage dividing resistor Rdv1 and the first thermistor T1 connected in series can be detected from the measured voltage of the first cell E1, and the resistance value of the first voltage dividing resistor Rdv1 is fixed, so that the control circuit 40 is divided. The resistance value of the first thermistor T1 can be estimated from the voltage at the pressure point Nd1. The control circuit 40 can estimate the temperature of the first cell E1 from the estimated resistance value of the first thermistor T1. Similar to the first cell E1, the control circuit 40 can estimate the temperatures of the second cell E2 and the third cell E3, respectively.

When measuring the temperature of the first cell E1 as described above, it is necessary to turn on the first external discharge switch Q1, and when the first external discharge switch Q1 is turned on, the first cell E1 to the first discharge resistor are turned on. A discharge current flows through Rd1. In order to suppress unnecessary capacity reduction, the control circuit 40 needs to shorten the temperature measurement period. For example, when the period of one cycle is set to 2s, the control circuit 40 measures the temperature of the cells E1-E3 for a period of 10 ms in one cycle.

In the example shown in FIG. 1, the voltage measurement circuit 30, the control circuit 40, the input resistance Rf1-Rf4 of the voltage measurement line L1-L4, the input capacitance Cf1-Cf3 of the voltage measurement line L1-L4, and the input of the gate signal line G1-G4. Capacities C1-C3 are mounted on the rigid substrate 20b. The control circuit 40 may be mounted on another rigid board. In that case, the rigid board on which the control circuit 40 is mounted and the rigid board 20b on which the voltage measurement circuit 30 is mounted are connected by a communication line.

Discharge resistance Rd1-Rd3, external discharge switch Q1-Q3, chip type thermistor T1-T3, voltage dividing resistor Rdv1-Rdv3, resistance R1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, Zener diode ZD1-ZD Is mounted on the flexible substrate 20a. If a plurality of chip-shaped thermistors T1-T3 are mounted on the flexible substrate 20a, the plurality of thermistors T1-T3 can be arranged in the vicinity of each of the plurality of cells E1-E3.

On the other hand, it is conceivable to attach a plurality of thermistors T1-T3 to the outer cans of the plurality of cells E1-E3, but in that case, a substrate on which the plurality of thermistors T1-T3 and the management device 20 are mounted. The number of wires and connectors between and is increased. In this respect, if a plurality of chip-shaped thermistors T1-T3 are mounted on the flexible substrate 20a, wiring and a connector used for temperature measurement are not required between the storage module 10 and the substrate on which the management device 20 is mounted.

As described above, when the first external discharge switch Q1 is on, the voltage measuring circuit 30 measures the voltage of the first voltage dividing resistor Rdv1 and the voltage dividing point Nd1 of the first thermistor T1 instead of the voltage across the first cell E1. doing. Conversely, when the first external discharge switch Q1 is on, the voltage of the first cell E1 cannot be measured. During the equalization process of the plurality of cells E1-E3, the voltage measuring circuit 30 cannot measure the voltage of the cells being discharged.

In the present embodiment, the control circuit 40 does not execute the equalization process while the vehicle is running (excluding the engine running), but executes the equalization process while the vehicle is stopped. The control circuit 40 executes the equalization process, especially when the vehicle is parked for a long period of time. In the present embodiment, the discharge resistor Rd1-Rd3 is mounted on the flexible substrate 20a to improve the heat dissipation of the discharge resistor Rd1-Rd3. Therefore, the discharge current during the equalization process can be made larger than usual, and the time required for the equalization process can be shortened. As a result, it is possible to reduce the variation in capacity between the plurality of cells E1 to E3 even in the equalization process during a short stop period.

In the present embodiment, the resistance value of the first voltage dividing resistor Rdv1 is set to a value corresponding to the range of the resistance value of the first thermistor T1. For example, the resistance value of the first voltage dividing resistor Rdv1 may be set to a value close to the resistance value of the first thermistor T1 at room temperature (25 ° C.). The resistance value of the first discharge resistor Rd1 is set to a value lower than the resistance value of the first voltage dividing resistor Rdv1. For example, the resistance value of the first thermistor T1 at room temperature (25 ° C.) may be set to about 10 kΩ, the resistance value of the first voltage dividing resistor Rdv1 may be set to 10 kΩ, and the resistance value of the first discharge resistor Rd1 may be set to 10 Ω.

FIG. 2 is a partial circuit diagram showing a basic unit configuration of the power supply system 1 according to the first embodiment. In the first embodiment, the voltage of the cell E1 can be detected based on the voltage measured by the voltage measuring circuit 30 when the switch Q1 is turned off. The temperature of the cell E1 can be estimated based on the voltage measured by the voltage measuring circuit 30 when the switch Q1 is turned on. Further, by keeping the switch Q1 on, a discharge current can be passed from the cell E1 to the discharge resistor Rd1 to adjust the capacity of the cell E1. As described above, in the basic unit configuration according to the first embodiment, three functions of the voltage measurement function of the cell E1, the temperature measurement function of the cell E1, and the capacity adjustment function of the cell E1 can be realized.

FIG. 3 is a partial circuit diagram showing a basic unit configuration of a power supply system according to a comparative example. The basic unit configuration according to the comparative example shown in FIG. 3 is a configuration in which the discharge resistance Rd1 is omitted from the basic unit configuration according to the first embodiment shown in FIG. 2 (see FIG. 1 of Patent Document 1 above). Similar to the basic unit configuration according to the first embodiment, the voltage of the cell E1 can be detected based on the voltage measured by the voltage measuring circuit 30 when the switch Q1 is turned off. The temperature of the cell E1 can be estimated based on the voltage measured by the voltage measuring circuit 30 when the switch Q1 is turned on.

In the comparative example, it is difficult to discharge for equalization processing even if the switch Q1 continues to be on. As described above, since the resistance value of the voltage dividing resistor Rdv1 is set to a value close to the resistance value of the thermistor T1 at room temperature, a high resistance is used for the voltage dividing resistor Rdv1. Therefore, the discharge current discharged from the cell E1 when the switch Q1 is turned on becomes a very small value. It takes too much time to adjust the capacity of cell E1. As described above, in the basic unit configuration according to the comparative example, only two functions, the voltage measurement function of the cell E1 and the temperature measurement function of the cell E1, can be realized.

On the other hand, in the basic unit configuration according to the first embodiment shown in FIG. 2, when the switch Q1 is turned on, a low resistance discharge is performed in parallel with the series circuit of the high resistance voltage dividing resistor Rdv1 and the high resistance thermistor T1. The resistor Rd1 is connected. Therefore, when the switch Q1 is turned on, a large discharge current can flow from the cell E1, and the capacity of the cell E1 can be adjusted in a short time.

As described above, according to the first embodiment, it is possible to increase the number of temperature measurement points while suppressing the increase in cost and the complexity of wiring. The thermistor wiring and measurement circuit can be shared with the existing equalization discharge circuit and voltage measurement circuit, and even if the number of thermistors is increased, the increase in the cost of parts other than the thermistor can be suppressed. Specifically, the multiplexer and A / D converter in the ASIC constituting the voltage measurement circuit 30 can be shared for voltage measurement and temperature measurement. Further, the discharge switch used for the equalization process can be used for switching between voltage measurement and temperature measurement. Therefore, even if the same number of thermistors as the cells are installed, the increase in cost and the complexity of wiring can be minimized.

(Embodiment 2)
FIG. 4 is a diagram showing the configuration of the power supply system 1 according to the second embodiment. Hereinafter, differences from the configuration of the power supply system 1 according to the first embodiment shown in FIG. 1 will be described. In the second embodiment, the external discharge switch Q1-Q3, the resistors R1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b and the Zener diode ZD1-ZD4 shown in FIG. 1 are omitted. In the second embodiment, the discharge resistor Rd1-Rd3, the chip-type thermistor T1-T3, and the voltage dividing resistor Rdv1-Rdv3 are mounted on the flexible substrate 20a. The mounting component of the rigid board 20b is the same as the mounting component of the rigid board 20b according to the first embodiment.

In the ON state of the first internal discharge switch S1, both ends of the first cell E1 conduct with each other via the first discharge resistor Rd1, the first internal discharge switch S1, and the second discharge resistor Rd2. Similarly, in the ON state of the second internal discharge switch S2, both ends of the second cell E2 are conducted via the second discharge resistor Rd2, the second internal discharge switch S2, and the third discharge resistor Rd3. Similarly, in the ON state of the third internal discharge switch S3, both ends of the third cell E3 conduct with each other via the third discharge resistor Rd3, the third internal discharge switch S3, and the fourth discharge resistor Rd4.

As described above, in the second embodiment, the discharge current flows in the ASIC. Therefore, in the second embodiment, it is necessary to use an ASIC having high heat resistance. Alternatively, the value of the discharge current needs to be smaller than that of the first embodiment. Or both need to be done.

Generally, the voltage of a lithium ion battery cell fluctuates in the range of about 3.0 to 4.25V. The input voltage range of the A / D converter in the ASIC constituting the voltage measurement circuit 30 is designed to be 0 to 5V, and the accuracy guarantee range is often set in the range of about 2.0 to 4.3V.

When the first internal discharge switch S1 is on, the voltage (about 4.0 V) of the first cell E1 is applied to the terminal on the side opposite to the voltage dividing point Nd1 side of the first voltage dividing resistor Rdv1. The voltage of the first cell E1 (about 4.0 V) is divided 1: 1 by the first discharge resistor Rd1 and the second discharge resistor Rd2 at the terminals on the opposite side of the voltage dividing point Nd1 of the first thermistor T1. The voltage (about 2.0V) is applied. Therefore, the voltage of the voltage dividing point Nd1 of the first voltage dividing resistor Rdv1 and the first thermistor T1 is a voltage in the range of about 2.0 to 4.0 V, and the voltage is divided by the first voltage dividing resistor Rdv1 and the first thermistor T1. It becomes the value.

As described above, in the second embodiment, the voltage range of the voltage dividing point Nd1 is narrower than that of the first embodiment, but the voltage range of the voltage dividing point Nd1 (about 2.0 to 4.0 V) is in the above-mentioned ASIC. The voltage is easy to enter the accuracy guarantee range (about 2.0 to 4.3V) of the A / D converter.

The resistance value of the NTC thermistor decreases as the temperature rises. For example, in a general NTC thermistor, the resistance value at room temperature is about 10 kΩ, the resistance value at low temperature is about 100 kΩ, and the resistance value at high temperature is about 2 kΩ. The low-pass filter in the input stage of the voltage measurement circuit 30 is composed of the combined resistance of three elements, the NTC thermistor T1, the discharge resistor Rd1, and the voltage dividing resistor Rdv1. When the discharge resistance Rd1 is set to about 10Ω and the voltage dividing resistance Rdv1 is set to about 10kΩ and the above NTC thermistor is used, the resistance value of the low-pass filter at low temperature is about 2kΩ and the resistance value at high temperature is about 10kΩ. The difference between the resistance values at low temperature and high temperature is about 5 times.

On the other hand, by inserting an input resistor Rf1-Rf3 of about 5 kΩ, the resistance value at low temperature can be set to about 15 kΩ and the resistance value at high temperature can be set to about 7 kΩ. The difference in resistance between low temperature and high temperature doubles. As a result, it is possible to reduce the change in the constant of the low-pass filter in the input stage of the voltage measurement circuit 30 due to the temperature change in the cells E1-E3. For example, in a configuration in which the input resistors Rf1-Rf3 are not inserted, when the cells E1-E3 become hot, the low-pass filter becomes too light and it becomes difficult to suppress aliasing.

As described above, according to the second embodiment, the same effect as that of the first embodiment is obtained. Further, in the second embodiment, the external discharge switch Q1-Q3, the resistors R1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, and the Zener diode ZD1-ZD4 are omitted by providing the discharge path inside the ASIC. Can be done. As a result, the number of parts can be reduced, and the circuit configuration outside the ASIC can be simplified.

FIG. 5 is a partial circuit diagram showing a basic configuration for two cells of the power supply system 1 according to the first embodiment. FIG. 6 is a partial circuit diagram showing a basic configuration for two cells of the power supply system 1 according to the second embodiment. In the configuration of FIG. 5, the first external discharge switch Q1 and the second external discharge switch Q2, which are vertically adjacent to each other, are controlled so as not to be turned on at the same time. When the first external discharge switch Q1 is on and the second external discharge switch Q2 is off, it is possible to ensure that the voltage of the second voltage measurement line L2 matches the negative electrode voltage of the first cell E1. Similarly, in the configuration of FIG. 6, the first internal discharge switch S1 and the second internal discharge switch S2 that are vertically adjacent to each other are controlled so as not to be turned on at the same time. With the first internal discharge switch S1 on and the second internal discharge switch S2 off, it is possible to ensure that the voltage of the second voltage measurement line L2 matches the negative electrode voltage of the first cell E1.

Based on the above considerations, the control circuit 40 alternately measures the temperature of the odd-numbered cells and the temperature of the even-numbered cells when measuring the temperatures of the plurality of cells connected in series. The temperatures of the plurality of cells may be measured one by one in order.

The present disclosure has been described above based on the embodiment. Embodiments are examples, and it will be understood by those skilled in the art that various modifications are possible for each of these components and combinations of processing processes, and that such modifications are also within the scope of the present disclosure. ..

In the above-described first and second embodiments, an example in which thermistors T1-T3 are installed in all cells E1-E3 has been described. In this respect, it is not always necessary to install thermistors in all cells. For example, one thermistor may be installed in two cells. If the thermistors are installed by skipping one, the temperatures of all thermistors can be measured at the same time.

In the voltage measuring line to which the thermistor is not connected, the voltage dividing resistor Rdv acts as a filter resistor. In that case, the input resistor Rf inserted into the voltage measurement line becomes unnecessary.

In the above-described first and second embodiments, an example in which the thermistor is installed near the cell and the temperature of the cell is measured has been described. In this regard, the thermistor may be installed in a hot spot on the substrate and used to measure the temperature of the substrate.

In the above-described first and second embodiments, an example in which the power supply system 1 is used for in-vehicle use has been described. In this respect, it can also be applied to stationary storage applications and electronic devices such as notebook PCs and smartphones.

In addition, the embodiment may be specified by the following items.

[Item 1]
A voltage measurement circuit (30) that is connected to each node of a plurality of cells (E1-E3) connected in series by a voltage measurement line (L1-L4) and measures the voltage of each of the plurality of cells (E1-E3). When,
A plurality of discharge circuits (Rd1-Rd3, Q1-Q3) connected in parallel with the plurality of cells (E1-E3), respectively, between two adjacent voltage measurement lines.
A plurality of insertion resistors (Rdv1-) inserted into the voltage measurement circuit (30) side from a node with the discharge circuit (Rd1-Rd3, Q1-Q3) on the plurality of voltage measurement lines (L1-L4). Rdv3) and
By controlling the plurality of discharge circuits (Rd1-Rd3, Q1-Q3) based on the voltages of the plurality of cells (E1-E3) measured by the voltage measurement circuit (30), the plurality of discharge circuits (Rd1-Rd3, Q1-Q3) are controlled. A control circuit (40) for executing equalization processing between cells (E1-E3) is provided.
Each of the plurality of discharge circuits (Rd1-Rd3, Q1-Q3) includes a discharge resistor (Rd1-Rd3) and a switch (Q1-Q3) connected in series.
This management device (20)
Further equipped with at least one temperature sensitive element (T1-T3) whose resistance value changes according to temperature,
The temperature sensitive element (T1) has a node on the voltage measurement circuit (30) side of the insertion resistor (Rdv1) on the voltage measurement line (L1) and a discharge resistor connected to the voltage measurement line (L1). Connected between the node between (Rd1) and the switch (Q1),
The control circuit (40) is characterized in that the temperature around the temperature sensitive element (T1) is estimated based on the voltage measured by the voltage measuring circuit (30) in the on state of the switch (Q1). Management device (20).
According to this, it is possible to strengthen the temperature monitoring of a plurality of cells (E1-E3) while suppressing the cost.
[Item 2]
The same number of temperature sensitive elements (T1-T3) as the plurality of cells (E1-E3) are installed.
The management device (20) according to item 1, wherein each of the plurality of temperature sensitive elements (T1-T3) is installed in the vicinity of each of the plurality of cells (E1-E3).
According to this, the temperature of all cells (E1-E3) can be measured.
[Item 3]
The resistance value of the insertion resistor (Rdv1-Rdv3) is set to a value corresponding to the range of the resistance value of the temperature sensitive element (T1-T3).
The management device (20) according to item 1 or 2, wherein the resistance value of the discharge resistance (Rd1-Rd3) is set to a value lower than the resistance value of the insertion resistance (Rdv1-Rdv3).
According to this, both the temperature measurement function and the equalized discharge function can be achieved at the same time.
[Item 4]
An input resistor (30) inserted into the voltage measuring circuit (30) from the voltage dividing points of the insertion resistor (Rdv1-Rdv3) and the temperature sensitive element (T1-T3) on the voltage measuring line (L1-L4). The management device (20) according to any one of items 1 to 3, further comprising Rf1-Rf4).
According to this, it is possible to reduce the change in the constant of the low-pass filter in the input stage of the voltage measurement circuit (30) due to the temperature change.
[Item 5]
Item 2. The item 1 to 4, wherein the plurality of discharge resistors (Rd1-Rd3) and at least one temperature-sensitive element (T1-T3) are mounted on a flexible substrate (20a). The management device (20) described.
According to this, the temperature sensitive element (T1-T3) can be installed in the vicinity of a plurality of cells (E1-E3).
[Item 6]
Multiple cells (E1-E3) connected in series and
The management device (20) according to any one of items 1 to 5 for managing the plurality of cells (E1-E3), and the management device (20).
A power supply system (1), which comprises.
According to this, it is possible to realize the power supply system (1) in which the temperature monitoring of a plurality of cells (E1-E3) is enhanced while suppressing the cost.

1 power supply system, 10 power storage module, 20 management device, 20a flexible board, 20b rigid board, 30 voltage measurement circuit, 40 control circuit, E1-E3 cell, T1-T3 thermista, L1-L4 voltage measurement line, G1-G4 gate Signal line, Rd1-Rd4 discharge resistor, Q1-Q3 external discharge switch, Rdv1-Rdv3 voltage division resistor, Rf1-Rf4 input resistor, Cf1-Cf3, C1-C3 input capacitance, S1-S3 internal discharge switch, R1a, R1b, R2a, R2b, R3a, R3b, R4a, R4b resistors, ZD1, ZD2, ZD3, ZD4 Zener diodes.

Claims (6)

A voltage measurement circuit that is connected to each node of a plurality of cells connected in series by a voltage measurement line and measures the voltage of each of the plurality of cells.
A plurality of discharge circuits connected in parallel with the plurality of cells, respectively, between two adjacent voltage measurement lines.
A plurality of insertion resistors inserted into the voltage measurement circuit side from the node with the discharge circuit on the plurality of voltage measurement lines, respectively.
A control circuit for executing equalization processing between the plurality of cells by controlling the plurality of discharge circuits based on the voltages of the plurality of cells measured by the voltage measurement circuit is provided.
Each of the plurality of discharge circuits includes a discharge resistor and a switch connected in series.
This management device
Further equipped with at least one temperature sensitive element whose resistance value changes according to temperature,
The temperature sensitive element is connected between the node on the voltage measurement circuit side of the insertion resistor on the voltage measurement line and the node between the discharge resistor connected to the voltage measurement line and the switch.
The control circuit is a management device characterized in that the temperature around the temperature sensitive element is estimated based on the voltage measured by the voltage measuring circuit in the on state of the switch. The same number of temperature sensitive elements as the plurality of cells are installed.
The management device according to claim 1, wherein each of the plurality of temperature sensitive elements is installed in the vicinity of each of the plurality of cells. The resistance value of the insertion resistor is set to a value corresponding to the range of the resistance value of the temperature sensitive element.
The management device according to claim 1 or 2, wherein the resistance value of the discharge resistance is set to a value lower than the resistance value of the insertion resistance. The invention according to any one of claims 1 to 3, further comprising the insertion resistor on the voltage measurement line and an input resistor inserted into the voltage measurement circuit side from the voltage dividing point of the temperature sensing element. Management device. The management device according to any one of claims 1 to 4, wherein the plurality of discharge resistors and the at least one temperature-sensitive element are mounted on a flexible substrate. With multiple cells connected in series
The management device according to any one of claims 1 to 5, which manages the plurality of cells.
A power supply system characterized by being equipped with.

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