JP2021143864A - Temperature detector - Google Patents

Abstract

To provide a temperature detector with which it is possible to shorten a temperature detection cycle.SOLUTION: A temperature detector 20 comprises a multiplexer 40, a filter circuit 50, a microcomputer 61, and a D/A converter 70. The multiplexer 40 includes input parts CH1, CH2, ..., CHn which are individually allocated for each of a plurality of temperature sensors 15, and an output part OUT which is common to the input parts CH1, CH2, ..., CHn. The filter circuit 50 is connected to the output part OUT and includes a capacitor 51. The microcomputer 61 detects the temperature of a battery module 11 on the basis of the output voltage of the filter circuit 50. The D/A converter 70 charges/discharges the capacitor 51 when switching the input part connected to the output part OUT to another input part among the input parts CH1, CH2, ..., CHn.SELECTED DRAWING: Figure 1

Description

The present invention relates to a temperature detection device that detects the temperature of a temperature detection target based on the output voltage of the temperature sensor.

As a device of this type, as described in Patent Document 1, a device including a multiplexer and an RC filter circuit is known. The multiplexer has an input unit individually assigned to each of a plurality of temperature sensors and an output unit common to each input unit, and sequentially switches the input unit connected to the output unit from each input unit. The RC filter circuit is connected to the output section and has a capacitor. The temperature detection device detects the temperature of the temperature detection target of the temperature sensor based on the output voltage of the RC filter circuit.

Japanese Unexamined Patent Publication No. 2005-224071

In the configuration described in Patent Document 1, a capacitor constituting an RC filter circuit is connected to the output section of the multiplexer. Therefore, when the input unit connected to the output unit of each input unit is switched to another input unit, the voltage of the capacitor changes to the temperature after switching due to the difference in the output voltage of the temperature sensor before and after the switching. It takes a waiting time until it becomes equal to the output voltage of the sensor. As a result, there is a concern that the temperature detection cycle of the temperature detection target becomes long. In particular, when the capacitance of the capacitor is increased in order to increase the noise removal effect, the waiting time becomes remarkably long, and there is a concern that the temperature detection cycle becomes excessively long.

It should be noted that the above-mentioned problems can occur similarly if the temperature detection device is not limited to the temperature detection device including the RC filter circuit but is provided with the filter circuit having a capacitor.

The present invention has been made in view of the above problems, and a main object thereof is to provide a temperature detection device capable of shortening a temperature detection cycle.

The present invention has an input unit individually assigned to each of a plurality of temperature sensors and an output unit common to each of the input units, and sequentially switches the input unit connected to the output unit from the input units. With a multiplexer
A filter circuit connected to the output unit and having a capacitor,
A detection unit that detects the temperature of the temperature detection target of the temperature sensor based on the output voltage of the filter circuit.
Each of the input units includes a charge / discharge unit that charges / discharges the capacitor when the input unit connected to the output unit is switched to another input unit.

The present invention includes a charging / discharging unit that charges / discharges a capacitor when the input unit connected to the output unit is switched to another input unit from each input unit. Therefore, even if the output voltage of the temperature sensor input to each input unit is different before and after the switching, the voltage of the capacitor can be brought close to the output voltage of the temperature sensor input to the input unit after the switching. As a result, the waiting time until the voltage of the capacitor becomes equal to the output voltage of the temperature sensor after switching can be shortened, and the temperature detection cycle of the temperature detection target can be shortened.

The block diagram of the temperature detection apparatus which concerns on 1st Embodiment. Flowchart of temperature detection processing. A time chart showing an example of temperature detection processing. A time chart showing a temperature detection process according to a comparative example. The block diagram of the temperature detection apparatus which concerns on 2nd Embodiment. A time chart showing an example of a pulse generated by a pulse generator. The block diagram of the temperature detection apparatus which concerns on other embodiment.

<First Embodiment>
Hereinafter, the first embodiment in which the temperature detection device according to the present invention is embodied will be described with reference to the drawings. The temperature detection device according to the present embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, for example.

As shown in FIG. 1, the temperature detection device 20 detects the temperature of the assembled battery 10 mounted on the vehicle. The assembled battery 10 is composed of a series connection body of a plurality of battery modules 11, and each battery module 11 is composed of a series connection body of a plurality of cell cells 12. In the present embodiment, the temperature detection device 20 constitutes a battery monitoring device that monitors the state of the assembled battery 10.

The assembled battery 10 includes a plurality of (n) temperature sensors 15. In the present embodiment, each temperature sensor 15 is individually provided corresponding to each battery module 11 and detects the temperature of each battery module 11. In this embodiment, a thermistor is used as the temperature sensor 15. Note that FIG. 1 shows a configuration in which one temperature sensor 15 is provided corresponding to each battery module 11, but the present invention is not limited to this. For example, two or more temperature sensors may be provided corresponding to each battery module 11.

The temperature detection device 20 includes a constant voltage power supply 30 and a resistor 31. The first end of the resistor 31 is connected to the constant voltage power supply 30, and the first end of the temperature sensor 15 is connected to the second end of the resistor 31. A ground is connected to the second end of the temperature sensor 15. In this embodiment, the constant voltage power supply 30 is shared by each temperature sensor 15.

The temperature detection device 20 includes a multiplexer 40. The multiplexer 40 has a jth input unit CHj (j = 1, 2, ..., N) individually assigned corresponding to each temperature sensor 15, and an output unit OUT common to each input unit CH1 to CHn. ing. The multiplexer 40 sequentially switches the input unit connected to the output unit OUT from the input units CH1 to CHn at a predetermined cycle. Each of the input units CH1 to CHn is connected to the first end of the temperature sensor 15 and the second end of the resistor 31. As a result, the voltage of the constant voltage power supply 30 divided by the temperature sensor 15 and the resistor 31 is input to each input unit CH1 to CHn.

The temperature detection device 20 includes a filter circuit 50. In the present embodiment, the filter circuit 50 is an RC low-pass filter circuit including a capacitor 51 and a filter resistor 52. Specifically, the output unit OUT of the multiplexer 40 is connected to the first end of the filter resistor 52, and the first end of the capacitor 51 is connected to the second end of the filter resistor 52. A ground is connected to the second end of the capacitor 51. The filter circuit 50 removes noise from the output voltage of the output unit OUT.

The temperature detection device 20 includes an A / D conversion unit 60, a microcomputer 61, and a storage unit 62. The input side of the A / D conversion unit 60 is connected to the filter circuit 50, and the output side is connected to the microcomputer 61. The A / D conversion unit 60 digitally converts the analog signal output from the filter circuit 50 and outputs it to the microcomputer 61. That is, the microcomputer 61 detects the output voltage of the filter circuit 50 based on the output signal of the A / D conversion unit.

In each cycle, the microcomputer 61 operates the multiplexer 40 in order to sequentially switch the input unit connected to the output unit OUT from the input units CH1 to CHn in a predetermined cycle. Specifically, the microcomputer 61 switches the input unit connected to the output unit OUT in order from the first input unit CH1 to the nth input unit CHn in one cycle, and again in the next cycle, the input connected to the output unit OUT. The unit is switched in order from the first input unit CH1 to the nth input unit CHn.

Here, the period from when the i-th input unit CHi (i = 1, 2, ..., 5) is separated from the output unit OUT until the i + 1 input unit CHi + 1 is connected to the output unit OUT is connected to the output unit OUT. It is an open period in which none of the first to nth input units CH1 to CHn is connected. Further, the period from the disconnection of the sixth input unit CH6 from the output unit OUT to the connection of the first input unit CH1 to the output unit OUT is also defined as the open state period. The open state is, for example, a state in which the output unit OUT is connected to the n + 1th input unit CHn + 1 when the temperature sensor 15 is not assigned to the n + 1 input unit CHn + 1 of the multiplexer 40. Further, in the present embodiment, the microcomputer 61 corresponds to the "detection unit" and the "operation unit".

The microcomputer 61 operates the multiplexer 40 to detect and detect the first to nth output voltages V1 to Vn of the filter circuit 50 when the first to nth input units CH1 to CHn are connected to the output unit OUT. Based on the first to nth output voltages V1 to Vn, the temperature of the battery module 11 to be detected by each temperature sensor 15 is detected. Further, the microcomputer 61 stores the detected first-to-nth output voltages V1 to Vn in the storage unit 62 in association with the first-to-nth input units CH1 to CHn. The storage unit 62 is a non-transitional substantive recording medium other than the ROM (for example, a non-volatile memory other than the ROM).

The temperature detection device 20 includes a D / A converter 70 corresponding to a “charge / discharge unit” and a switch 71 as a connection unit. The switch 71 is provided in an electric path connecting the D / A converter 70 and the first end of the capacitor 51, and is turned on or off by the microcomputer 61. When the switch 71 is turned on, the D / A converter 70 and the capacitor 51 are electrically connected. On the other hand, when the switch 71 is turned off, the D / A converter 70 and the capacitor 51 are electrically cut off.

The microcomputer 61 sets the target voltage Vt of the D / A converter 70, and controls the output voltage of the D / A converter 70 to the set target voltage Vt.

In this embodiment, a configuration is adopted in which the temperature detection cycle of each battery module 11 by the microcomputer 61 can be shortened. A configuration that shortens the temperature detection cycle is adopted, for example, for the reasons described below. That is, as the assembled battery 10, an assembled battery composed of a versatile storage battery such as a storage battery of 18650 may be used instead of a dedicated product for a vehicle. In this case, since the assembled battery 10 is not a dedicated product, it is desired to increase the number of temperature detection points of the assembled battery 10 in order to improve safety. In this case, it is required to shorten the temperature detection cycle in one cycle for temperature detection using the multiplexer 40.

The temperature detection process executed by the microcomputer 61 will be described with reference to FIG.

In step S10, it is determined whether or not the jth output voltage Vj (j = 1, 2, ..., N) of the previous cycle is stored in the storage unit 62. The situation in which the negative determination is made in step S10 is, for example, the situation in which the temperature detection process is first executed after the microcomputer 61 is started.

If it is determined in step S10 that the jth output voltage Vj of the previous cycle is not stored, the process proceeds to step S11, and the multiplexer 40 is operated to connect the jth input unit and the output unit OUT.

In step S12, the process waits until the first specified period T1 elapses after the j-input unit CHj is connected to the output unit OUT. The first specified period T1 is a period of waiting for stabilization until the voltage Vc of the capacitor 51 becomes the input voltage of the jth input unit CHj or its vicinity.

If it is determined in step S12 that the first specified period T1 has elapsed, the process proceeds to step S13, and the jth output voltage Vj is detected in this cycle. Then, the detected j-th output voltage Vj is stored in the storage unit 62 in association with the j-th input unit CHj.

In step S14, the multiplexer 40 is switched to the open state.

In step S15, it is determined whether or not the variable j is n. This process is for determining whether or not one cycle of temperature detection has been completed. If a negative determination is made in step S15, it is determined that one cycle has not been completed, and the process proceeds to step S16. In step S16, the variable j is incremented by 1, and then the process proceeds to step S10. On the other hand, when it is determined in step S15 that the variable j is n, it is determined that one cycle has been completed, the process proceeds to step S10, and the process proceeds to the next cycle.

If it is determined in step S10 that the jth output voltage Vj (corresponding to the "target output voltage") of the previous cycle is stored, the process proceeds to step S18, and the jth output voltage Vj of the previous cycle is stored in the storage unit. Obtained from 62.

In step S19, the switch 71 is switched on. As a result, the D / A converter 70 and the capacitor 51 are electrically connected.

In step S20, the D / A converter 70 is operated in order to control the output voltage of the D / A converter 70 to the target voltage Vt. In the present embodiment, the target voltage Vt is set to the same voltage as the jth output voltage Vj of the previous cycle acquired in step S18. When the voltage Vc of the capacitor 51 is lower than the target voltage Vt, the capacitor 51 is charged by controlling the output voltage of the D / A converter 70, and the voltage Vc of the capacitor 51 rises toward the target voltage Vt. On the other hand, when the voltage Vc of the capacitor 51 is higher than the target voltage Vt, the capacitor 51 is discharged by controlling the output voltage of the D / A converter 70, and the voltage Vc of the capacitor 51 drops toward the target voltage Vt.

In step S21, the process waits until the second specified period T2 elapses after the control of the output voltage of the D / A converter 70 to the target voltage Vt is started. The process of step S21 is a process for determining whether or not the voltage Vc of the capacitor 51 has reached the target voltage Vt. The second specified period T2 is set to a shorter period than the first specified period T1.

If it is determined in step S21 that the second specified period T2 has elapsed, the process proceeds to step S22, and the switch 71 is switched off.

In step S23, the jth input unit CHj (corresponding to the “target input unit”) and the output unit OUT are connected by operating the multiplexer 40.

In step S24, the process waits until the third specified period T3 elapses after the j-input unit CHj and the output unit OUT are connected. The process of step S24 is a process for determining whether or not the voltage Vc of the capacitor 51 has become the input voltage of the jth input unit CHj. The third specified period T3 is set to a shorter period than the first specified period T1. In particular, in the present embodiment, the added value of the second specified period T2 and the third specified period T3 is set to a period shorter than the first specified period T1.

If it is determined in step S24 that the third specified period T3 has elapsed, the process proceeds to step S13, and the jth output voltage Vj is detected in this cycle. Then, the detected j-th output voltage Vj is stored in the storage unit 62 in association with the j-th input unit CHj.

The temperature detection process will be described with reference to the time chart of FIG. FIG. 3A shows the transition of the operating state of the multiplexer 40, and FIG. 3B shows the transition of the operating state of the switch 71. FIG. 3C shows the transition of the operating state of the D / A converter 70, and FIG. 3D shows the transition of the voltage Vc of the capacitor 51. The example shown in FIG. 3 is a case where the connection target to the output unit OUT is switched from the first input unit CH1 to the second input unit CH2.

At time t1, the first input unit CH1 is disconnected from the output unit OUT, and the multiplexer 40 is opened.

At time t2, the switch 71 is switched on, and at time t3, the D / A converter 70 is operated in order to reduce the voltage Vc of the capacitor 51 to the target voltage Vt. This target voltage Vt is set to the second output voltage V2 in the previous cycle.

At time t4, when the second specified period T2 has elapsed from time t2, the control of the output voltage of the D / A converter 70 is stopped, and at time t5, the switch 71 is switched off.

After that, at time t6, the second input unit CH2 is connected to the output unit OUT. Then, at the time t7 when the third specified period T3 has elapsed from the time t6, the voltage Vc of the capacitor 51 is detected as the second output voltage V2 in this cycle.

At time t6, the voltage Vc of the capacitor 51 is set to the second output voltage V2 in the previous cycle. Therefore, the difference between the voltage Vc of the capacitor 51 at time t6 and the input voltage of the second input unit CH2 in this cycle can be reduced. As a result, the third specified period T3 for waiting for stability can be set to a short period, and the temperature detection cycle can be shortened.

On the other hand, in the comparative example shown in FIG. 4, the temperature detection cycle becomes long. A comparative example is a configuration in which the D / A converter 70 and the switch 71 are removed from the configuration shown in FIG. 4 (a) and 4 (b) correspond to FIGS. 3 (a) and 3 (d) above. The broken line in FIG. 4B shows the transition of the voltage Vc of the capacitor 51 according to the present embodiment shown in FIG. 3D.

In the comparative example, at time t1, the first input unit CH1 is disconnected from the output unit OUT, and the multiplexer 40 is opened. After that, at time t2, the second input unit CH2 is connected to the output unit OUT, and at time t3 when the first specified period T1 elapses from time t2, the voltage Vc of the capacitor 51 is set as the second output voltage V2 in this cycle. Detected. In the comparative example, since it is necessary to set the first specified period T1 for a long time in order to wait for the voltage Vc of the capacitor 51 to stabilize, the temperature detection cycle becomes long.

As described above, according to the present embodiment, even if the output voltage of the temperature sensor 15 input to each input unit is different before and after switching the input unit connected to the output unit OUT, the voltage of the capacitor 51 Vc can be brought close to the output voltage of the temperature sensor 15 input to the input unit after switching. As a result, the waiting time until the voltage Vc of the capacitor 51 becomes equal to the output voltage of the temperature sensor 15 after switching can be shortened, and the temperature detection cycle of the battery module 11 can be shortened.

In particular, in the present embodiment, since the target voltage Vt is set to the same voltage as the jth output voltage Vj of the previous cycle, the effect of shortening the temperature detection cycle can be enhanced.

<Second Embodiment>
Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, as shown in FIG. 5, the temperature detection device 20 includes a pulse generator 72 instead of the D / A converter 70. In FIG. 5, the same components as those shown in FIG. 1 above are designated by the same reference numerals for convenience.

In the microcomputer 61, instead of the process of step S20 in FIG. 2, the pulse generator 72 controls the voltage Vc of the capacitor 51 to the target voltage Vt set to the same voltage as the jth output voltage Vj of the previous cycle. The process of manipulating the generated pulse width Ton is performed. As shown in FIG. 6, the pulse width Ton is defined as an output period of a predetermined voltage in the pulse generation cycle Tp. For example, when the pulse width Ton is larger than the reference width Ts (<Tp), the larger the pulse width Ton, the greater the degree of increase in the voltage Vc of the capacitor 51, and when the pulse width Ton is smaller than the reference width Ts, the pulse width. The smaller the ton, the greater the degree of decrease in the voltage Vc of the capacitor 51.

According to the present embodiment described above, the same effect as that of the first embodiment can be obtained.

<Other Embodiments>
Each of the above embodiments may be modified as follows.

As shown in FIG. 7, a capacitor 32 for static electricity countermeasures may be connected between the first end of the temperature sensor 15 and each input portion CHj of the multiplexer 40. In FIG. 7, the same reference numerals are given to the same configurations as those shown in FIG. 1 above for convenience.

Unlike the configuration shown in FIG. 7, in the case where the filter circuit 50 is connected between each input portion CHj of the multiplexer 40 and the first end of the temperature sensor 15, the capacitor 51 constituting the filter circuit 50 is used. It will also serve as a capacitor for static electricity countermeasures. As a result, there is a concern that restrictions will be imposed on the setting of the capacity of the capacitor with an emphasis on measures against static electricity. On the other hand, according to the configuration shown in FIG. 7 in which the filter circuit 50 is connected to the output unit OUT of the multiplexer 40, the capacity of the capacitor 32 with an emphasis on measures against static electricity can be freely set. The configuration shown in FIG. 5 of the second embodiment may also be provided with the capacitor 32 for static electricity countermeasures.

The target voltage Vt is not limited to the same voltage as the j output voltage Vj of the previous cycle, but is not limited to the j output voltage Vj of the cycle two times before, for example, the j output voltage Vj of the cycle two times before. It may be set to the same voltage.

The target voltage Vt is not limited to the same voltage as the jth output voltage Vj of the previous cycle, and the j-1th input unit CHj-1 selected immediately before the jth input unit CHj in this cycle is the output unit. It may be set to a voltage between the output voltage of the filter circuit 50 when connected to OUT and the jth output voltage Vj of the previous cycle. Even in this case, the effect of shortening the temperature detection cycle can be obtained.

-The filter circuit may be, for example, an LC low-pass filter circuit instead of the RC low-pass filter circuit. In this case, the first end of the capacitor constituting the LC low-pass filter circuit is connected to the output unit OUT, and the second end of the capacitor is connected to the ground. Further, the first end of the inductor constituting the LC low-pass filter circuit is connected to the first end of the capacitor, and the second end of the inductor is connected to the A / D conversion unit 60.

Further, the filter circuit is not limited to the low-pass filter circuit, and may be, for example, a band-pass filter circuit. Examples of this circuit include a bandpass filter circuit including a pair of capacitors and a pair of inductors.

The assembled battery 10 may be configured by a parallel connection of a plurality of battery modules 11, or may be configured by a series connection of a plurality of battery modules 11 connected in parallel.

-The temperature sensor is not limited to the thermistor, and may be, for example, a temperature sensitive diode.

-The temperature detection device is not limited to the one mounted on the vehicle.

The controls and methods thereof described in the present disclosure are provided by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may be realized. Alternatively, the controls and methods thereof described in the present disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. It may be realized by one or more dedicated computers configured. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

15 ... temperature sensor, 20 ... temperature detector, 40 ... multiplexer, 50 ... filter circuit, 61 ... microcomputer, 70 ... D / A converter.

Claims (9)

It has an input unit (CHj) individually assigned to each of the plurality of temperature sensors (15) and an output unit (OUT) common to each of the input units, and is connected to the output unit from among the input units. A multiplexer (40) that sequentially switches the input section and
A filter circuit (50) connected to the output unit and having a capacitor (51),
A detection unit (61) that detects the temperature of the temperature detection target of the temperature sensor based on the output voltage of the filter circuit, and
A temperature detection device including charge / discharge units (70, 72) that charge / discharge the capacitor when the input unit connected to the output unit is switched to another input unit among the input units. A storage unit (62) that stores the output voltage of the filter circuit detected by the detection unit in association with the input unit connected to the output unit.
A claim including an operation unit (61) that sets a target voltage based on an output voltage stored in the storage unit and operates the charge / discharge unit in order to control the voltage of the capacitor to the set target voltage. Item 1. The temperature detection device according to item 1. In each cycle, the multiplexer sequentially switches the input unit connected to the output unit from the input units.
In the storage unit, when the target input unit sequentially selected from the respective input units in the previous cycle is connected to the output unit, the output voltage of the filter circuit detected is connected to the target input unit. Associated and stored,
The operation unit
The target voltage corresponding to the target input unit of the current cycle is set based on the target output voltage which is the output voltage corresponding to the target input unit of the previous cycle stored in the storage unit.
In this cycle, the period from when the input unit selected immediately before the target input unit from each of the input units is separated from the output unit until the target input unit is connected to the output unit. The temperature detection device according to claim 2, wherein the charging / discharging unit is operated in order to control the voltage of the capacitor to the target voltage corresponding to the target input unit. The operation unit controls the target voltage corresponding to the target input unit in the current cycle when the input unit selected immediately before the target input unit in the current cycle is connected to the output unit. The temperature detection device according to claim 3, wherein the voltage is set between the output voltage of the circuit and the target output voltage. The operation unit sets the target voltage corresponding to the target input unit in the current cycle to the same voltage as the output voltage corresponding to the target input unit stored in the storage unit in the previous cycle. The temperature detection device according to 3. The temperature detecting device according to any one of claims 1 to 5, wherein the charging / discharging unit is a pulse generator (72). The temperature detecting device according to any one of claims 1 to 5, wherein the charging / discharging unit is a D / A converter (70). The temperature detection device according to any one of claims 1 to 7, wherein the temperature detection target of the temperature sensor is the battery module (11) constituting the assembled battery (10). The temperature detection device according to any one of claims 1 to 8, wherein the filter circuit is an RC low-pass filter circuit.

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