JP2012033351A - Battery temperature rising circuit and battery temperature rising device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat a secondary battery and determine a temperature of the secondary battery.SOLUTION: A battery temperature rising circuit has: a heater 12 arranged in the vicinity of a secondary battery 11, and that heats the secondary battery 11, and whose resistance value changes depending on a temperature; a switch 14 interposed between a power supply 13 and the heater 12; a heating controller 15 that on-off controls the switch 14 to control heating of the secondary battery 11 by the heater 12; and a temperature determination part 18 that calculates a resistance value of the heater 12 when heating of the secondary battery 11 by the heater 12 is stopped, and determines the temperature of the secondary battery 11 from the resistance value.

Description

  The present invention relates to a battery temperature raising circuit and a battery temperature raising device for raising the temperature of a secondary battery.

  Conventionally, since the low temperature characteristic of the secondary battery is not so good, an apparatus configured to heat the secondary battery using a heater has been proposed (for example, see Patent Document 1). The device described in Patent Document 1 incorporates a thermostat for preventing overheating and preventing overcooling, and always keeps the inside of the device at an appropriate temperature. On the other hand, there is a need to monitor the temperature of the secondary battery and adjust the charge / discharge current according to the temperature.

JP-A-11-214048

  However, in the apparatus described in Patent Document 1, the temperature of the secondary battery can be detected by heating the secondary battery with a heater, but the temperature of the secondary battery cannot be detected. If a temperature detection unit is separately provided to detect the temperature of the secondary battery, the number of parts increases and the cost also increases. Therefore, it is desired that the temperature of the secondary battery can be determined with a simple configuration without separately providing a temperature detection unit.

  The present invention solves the above-described conventional problems, and provides a battery temperature raising circuit and a battery temperature raising device capable of heating a secondary battery with a simple configuration and determining the temperature of the secondary battery. The purpose is to do.

  The battery heating circuit according to the present invention is disposed in the vicinity of the secondary battery, heats the secondary battery, and changes a resistance value according to temperature, and between the power source and the heating part. A heating control unit that controls on / off of the switch to control heating of the secondary battery by the heating unit, and heating of the secondary battery by the heating unit is stopped A temperature determination unit that obtains a resistance value of the heating unit and determines a temperature of the secondary battery from the resistance value.

  According to this configuration, when the switch is turned on, the heating unit disposed in the vicinity of the secondary battery is energized to heat the secondary battery. Further, the resistance value of the heating part is obtained when the heating of the secondary battery is stopped. Since the resistance value of the heating part changes according to the temperature, the temperature of the heating part, that is, the temperature of the secondary battery is determined from the resistance value. Therefore, it is possible to heat the secondary battery and determine the temperature of the secondary battery with a simple configuration without separately providing a temperature detection unit.

  Further, in the above battery temperature rising circuit, the heating unit is provided in the vicinity of a plurality of secondary batteries, and has a plurality of heating units that respectively heat the plurality of secondary batteries, and the switch includes A plurality of switches interposed between the power source and the plurality of heating units, and the heating control unit controls on / off of the plurality of switches, and the two heating units Each of the secondary battery heating is controlled, and the temperature determination unit obtains a resistance value of the heating unit in which heating of the secondary battery is stopped among the plurality of heating units, and corresponds to the heating unit from the resistance value It is preferable to determine the temperature of the secondary battery.

  According to this configuration, when each switch is turned on, each heating unit disposed in the vicinity of each secondary battery is energized, and each secondary battery is heated. Moreover, the resistance value of the heating part in which the heating of the secondary battery is stopped among the plurality of heating parts is obtained. Since the resistance value of the heating part changes according to the temperature, the temperature of the heating part, that is, the temperature of the secondary battery is determined from the resistance value. Accordingly, each secondary battery can be heated and the temperature of each secondary battery can be individually determined with a simple configuration without separately providing a temperature detection unit.

  In the battery temperature raising circuit, it is preferable that the temperature determination unit obtains a resistance value of the heating unit at a preset sampling interval while heating of the secondary battery is stopped. According to this configuration, since the resistance value of the heating unit is obtained at a preset sampling interval while heating of the secondary battery is stopped, the temperature of the secondary battery is determined in real time at each sampling interval. Can do.

  Moreover, in the above battery temperature rising circuit, the heating unit preferably has a positive temperature coefficient. According to this configuration, since the heating unit has a positive temperature coefficient, the resistance value increases when the temperature increases when the heating unit is energized. Therefore, the secondary battery is suitably heated by the heating unit with simple constant voltage control. can do.

  In the battery temperature raising circuit, the heating unit is preferably a PTC heater. According to this configuration, since the heating unit is a PTC heater, the resistance value increases when the temperature rises when the PTC heater is energized. Therefore, the secondary battery is suitably heated by the PTC heater with simple constant voltage control. be able to.

  In the battery temperature increasing circuit, the temperature determination unit preferably determines whether the resistance value is equal to or higher than a preset value. According to this configuration, it is determined whether or not the resistance value is greater than or equal to a preset set value. Here, when the heating of the secondary battery by the heating unit is stopped, the resistance value of the heating unit having a positive temperature coefficient increases to a set value or more because the secondary battery is abnormally heated. It is thought that. Therefore, it is possible to determine abnormal heat generation of the secondary battery with a simple configuration without separately providing a temperature detection unit.

  A battery temperature raising apparatus according to the present invention includes the battery temperature raising circuit and the secondary battery. According to this configuration, when the switch is turned on, the heating unit disposed in the vicinity of the secondary battery is energized to heat the secondary battery. Further, the resistance value of the heating part is obtained when the heating of the secondary battery is stopped. Since the resistance value of the heating part changes according to the temperature, the temperature of the heating part, that is, the temperature of the secondary battery is determined from the resistance value. Therefore, it is possible to heat the secondary battery and determine the temperature of the secondary battery with a simple configuration without separately providing a temperature detection unit.

  According to the present invention, the secondary battery is heated by the heating unit that is disposed in the vicinity of the secondary battery, and the resistance value changes according to the temperature, and when the heating of the secondary battery is stopped, Since the temperature of the secondary battery is determined by obtaining the resistance value of the part, the temperature of the secondary battery can be determined while heating the secondary battery with a simple configuration.

The circuit diagram which shows the structure of the battery temperature rising circuit in 1st Embodiment of this invention. The figure which shows an example of the resistance / temperature characteristic of a PTC heater. The circuit diagram which shows the structure of the battery temperature rising circuit in 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a circuit diagram showing a configuration of a battery temperature raising circuit in the first embodiment of the present invention, and FIG. 2 is a diagram showing an example of resistance / temperature characteristics of a PTC heater. The battery temperature raising circuit heats a plurality of secondary batteries 11 (12 in FIG. 1) and determines their temperatures. The PTC heater 12, the first and second power supply units 13 and 17, and the switch 14 , 16, a heater control unit 15 and a temperature determination unit 18. As the switches 14 and 16, for example, electromagnetic relays or solid state relays can be used.

  The PTC heater 12 is made of a resistor having a positive temperature coefficient so that a pair of secondary batteries including the PTC heater 12 and the four secondary batteries 11 are in a one-to-one relationship in the vicinity of each secondary battery 11. It arrange | positions and it is comprised so that each secondary battery 11 may be heated. That is, as shown in FIG. 1, the PTC heater 12 is composed of three resistors connected in parallel, and each resistor is heated so that four secondary batteries 11 are heated by one resistor. Is arranged. One end of the PTC heater 12 is connected to the first power supply unit 13 via the switch 14, and the other end is grounded. One end of the PTC heater 12 is further connected to the second power supply unit 17 through the resistor R1 and the switch 16, and is also connected to the temperature determination unit 18. The PTC heater 12 has, for example, a resistance / temperature characteristic RT as shown in FIG. 2, that is, a relationship between a resistance value and a temperature. In FIG. 2, the vertical axis represents the resistance value, and the horizontal axis represents the temperature. As shown in FIG. 2, the resistance value of the PTC heater 12 gradually increases from a low temperature to about 60 ° C., rapidly increases around 80 ° C., and has an exponential characteristic.

  The heater control unit 15 controls energization from the first power supply unit 13 to the PTC heater 12 by controlling on / off of the switch 14 to control heating of the secondary battery 11. The power supply voltage of the first power supply unit 13 is set to such a level that the PTC heater 12 is heated to, for example, about 60 ° C. when the switch 14 is turned on and the PTC heater 12 is energized. As shown in FIG. 2, the resistance value when the PTC heater 12 is about 60 ° C. is about 5.0Ω. The power supply voltage of the first power supply unit 13 is set higher than the above level, and the heater control unit 15 controls the switch 14 to be turned on / off with a preset duty ratio so that the PTC heater 12 is energized. Good.

  The temperature determination unit 18 holds, for example, the resistance / temperature characteristic RT of the PTC heater 12 shown in FIG. Then, the temperature determination unit 18 turns on the switch 16 from the time when the heating of the secondary battery 11 by the PTC heater 12 is stopped, and sets the resistance value of the PTC heater 12 at a preset sampling interval (for example, 5 seconds). Ask. That is, the temperature determination unit 18 turns on the switch 16 to energize the series circuit including the resistor R1 and the PTC heater 12 from the second power supply unit 17, and the power supply voltage of the second power supply unit 17 changes the resistance R1 and the PTC heater 12 to each other. The resistance value of the PTC heater 12 is obtained by detecting the divided voltage divided by.

  The temperature determination unit 18 determines the temperature of the PTC heater 12 from the obtained resistance value and the resistance / temperature characteristic RT of the PTC heater 12 held in the built-in memory. The temperature determination unit 18 holds that the temperature difference between the PTC heater 12 and the secondary battery 11 is about 20 ° C. in the built-in memory, and determines the temperature of the secondary battery 11 from the temperature of the PTC heater 12. To do. The temperature difference between the PTC heater 12 and the secondary battery 11 is obtained in advance by, for example, experiments, and stored in the built-in memory of the temperature determination unit 18. As shown in FIG. 2, for example, when the obtained resistance value is about 4.0Ω, the temperature determination unit 18 sets the temperature of the PTC heater 12 to about 50 ° C. (that is, the temperature of the secondary battery 11 is about 70 ° C.). judge.

  In addition, the temperature determination unit 18 determines that the resistance value of the obtained PTC heater 12 is equal to or higher than a preset value (for example, 9.0Ω in this embodiment), that is, when the temperature of the PTC heater 12 is 80 ° C. or higher. It is determined that the secondary battery 11 is abnormally heated. That is, since the temperature difference between the PTC heater 12 and the secondary battery 11 is about 20 ° C., the temperature of the secondary battery 11 is 100 ° C. when the temperature of the PTC heater 12 is 80 ° C. No. 18 determines that the secondary battery 11 is abnormally heated when the temperature of the secondary battery 11 is 100 ° C. or higher. The power supply voltage of the second power supply unit 17 is set to a low level such that the temperature of the PTC heater 12 does not increase greatly even when the PTC heater 12 is energized.

  The operation of the battery heating circuit configured as described above will be described. For example, when the battery temperature raising circuit shown in FIG. 1 is mounted on a system (for example, an electric vehicle) provided with an outside air temperature detection unit, the temperature detected by the outside air temperature detection unit is equal to or lower than a first set temperature set in advance. Then, the heater control unit 15 turns on the switch 14 and energizes the PTC heater 12 from the first power supply unit 13 to heat the secondary battery 11. When the detected temperature reaches the second set temperature set higher than the first set temperature, the heater control unit 15 turns off the switch 14 and stops the heating of the secondary battery 11. In addition, the heater control unit 15 notifies the temperature determination unit 18 of the on / off state of the switch 14, that is, information on whether or not the secondary battery 11 is being heated by the PTC heater 12.

  When the heating of the secondary battery 11 by the PTC heater 12 is stopped, the temperature determination unit 18 turns on the switch 16 and detects the divided voltage of the PTC heater 12 at a preset sampling interval. The resistance value of the PTC heater 12 is calculated from the voltage, the known resistance value of the resistor R1, and the power supply voltage of the second power supply unit 17.

  Then, the temperature determination unit 18 determines the temperature of the PTC heater 12, that is, the secondary battery 11, from the calculated resistance value and the resistance / temperature characteristic RT shown in FIG. Further, the temperature determination unit 18 determines whether or not the calculated resistance value is a preset setting value, for example, 9Ω or more. Then, it is determined that the PTC heater 12 is heated. Then, the temperature determination unit 18 notifies, for example, an external charge control circuit that controls charging of the secondary battery 11 that the secondary battery 11 is abnormally generating heat. In addition, when the temperature determination unit 18 is notified by the heater control unit 15 that heating of the secondary battery 11 by the PTC heater 12 is started, the temperature determination unit 18 turns off the switch 16 and calculates the resistance value of the PTC heater 12. Stop.

  As described above, according to the first embodiment, the heater control unit 15 controls the on / off of the switch 14, controls the energization from the first power supply unit 13 to the PTC heater 12, and closes the secondary battery 11. Since the secondary battery 11 is heated by the disposed PTC heater 12, the secondary battery 11 can be suitably heated.

  Further, according to the first embodiment, when the heating of the secondary battery 11 by the PTC heater 12 is stopped, the temperature determination unit 18 turns on the switch 16 to calculate the resistance value of the PTC heater 12, Since the temperature of the PTC heater 12 is determined from the resistance / temperature characteristic RT of the PTC heater 12 held in the built-in memory and the calculated resistance value, the temperature of the secondary battery 11 can be determined. Therefore, according to the first embodiment, the secondary battery 11 is heated and the temperature of the secondary battery 11 is determined with a simple configuration simply including the PTC heater 12 without separately providing a temperature detection unit. Is possible.

  Further, according to the first embodiment, since the PTC heater 12 whose resistance value increases as the temperature rises is used as the heating unit that heats the secondary battery 11, energization control to the PTC heater 12 is simple. There is an advantage that a constant voltage control is sufficient.

  Further, according to the first embodiment, as shown in FIG. 2, since the change in the resistance value of the PTC heater 12 is large in the vicinity of 80 ° C., it is reliably determined whether or not the resistance value is greater than or equal to the set value. Therefore, the abnormal heat generation of the secondary battery 11 can be suitably determined.

(Second Embodiment)
FIG. 3 is a circuit diagram showing a configuration of a battery temperature raising circuit in the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and it demonstrates centering on a different point from 1st Embodiment.

  The battery temperature increasing circuit of the second embodiment includes PTC heaters 121 to 123 that are individually disposed in the vicinity of a plurality (three in FIG. 3) of secondary batteries 111 to 113. The PTC heaters 121 to 123 each have the same resistance / temperature characteristics as the PTC heater 12 of the first embodiment. Further, the PTC heaters 121 to 123 are connected to the respective parts in the same manner as the PTC heater 12 of the first embodiment. Specifically, one ends of the PTC heaters 121 to 123 are connected to the first power supply unit 13 via switches 141 to 143, respectively, and the other ends are grounded. One end of each of the PTC heaters 121 to 123 is further connected to the second power supply unit 17 via the resistors R11 to R13 and the switches 161 to 163, and is also connected to the temperature determination unit 18.

  The heater control unit 15 controls the energization from the first power supply unit 13 to the PTC heaters 121 to 123 by individually turning on and off the switches 141 to 143, so that the secondary batteries 111 to 111 by the PTC heaters 121 to 123 are controlled. The heating of 113 is controlled individually. The temperature determination unit 18 turns on the switches 161 to 163 when the heating of the secondary batteries 111 to 113 by the PTC heaters 121 to 123 is stopped, and from the second power supply unit 17, the resistors R11 to R13 and Electricity is passed through the series circuits composed of the PTC heaters 121 to 123, respectively. The temperature determination unit 18 then divides the divided voltage obtained by dividing the power supply voltage of the second power supply unit 17 by the resistors R11 to R13 and the PTC heaters 121 to 123 at a preset sampling interval (for example, 5 seconds). By detecting, the resistance values of the PTC heaters 121 to 123 are obtained.

  Further, the temperature determination unit 18 determines the temperatures of the PTC heaters 121 to 123 from the obtained resistance value and the resistance / temperature characteristics of the PTC heaters 121 to 123 held in the built-in memory, and the determined temperature And the temperature of the secondary batteries 111 to 113 is determined from the temperature difference (for example, 20 ° C.) between the temperature of the PTC heaters 121 to 123 and the temperature of the secondary batteries 111 to 113 held in the built-in memory. Moreover, the temperature determination part 18 each determines whether the calculated | required resistance value of the PTC heaters 121-123 is more than a setting value, and if either is more than a setting value, 2 corresponding to the PTC heaters 121-123 is determined. Each of the secondary batteries 111 to 113 is determined to be abnormally heated.

  As described above, according to the second embodiment, the heater control unit 15 controls the on / off of the switches 141 to 143 to the PTC heaters 121 to 123 disposed in the vicinity of the secondary batteries 111 to 113, respectively. Since the energization from the first power supply unit 13 is controlled, the secondary batteries 111 to 113 can be individually heated. Further, according to the second embodiment, when the heating of the secondary batteries 111 to 113 by the PTC heaters 121 to 123 is stopped, the temperature determination unit 18 turns on the switches 161 to 163 to turn on the PTC heaters 121 to 121. Each of the resistance values of 123 is calculated. Therefore, the temperature of the secondary batteries 111 to 113 can be individually determined without separately providing a temperature detection unit. Further, according to the second embodiment, it is possible to identify the secondary batteries 111 to 113 that have abnormally generated heat.

  Moreover, according to 2nd Embodiment, since the PTC heaters 121-123 whose resistance value increases with a temperature rise are used as a heating part which heats the secondary batteries 111-113, the first embodiment and Similarly, there is an advantage that the energization control to the PTC heaters 121 to 123 may be simple constant voltage control.

(Other)
In the first embodiment shown in FIG. 1, twelve secondary batteries 11 are heated, but the number of secondary batteries is not limited to twelve. In the second embodiment shown in FIG. 3, the three secondary batteries 111 to 113 are individually heated. However, the number of secondary batteries is not limited to three, and may be two or four or more. May be.

  Further, the resistance / temperature characteristic RT of the PTC heater 12 shown in FIG. 2 is an example, and is not limited to that shown in FIG. 2, but is a temperature for determining abnormal heat generation of the secondary battery 11 (in FIG. 2, the PTC heater 12 It is preferable to have a characteristic that the resistance value largely changes in the vicinity of the temperature of 80 ° C.).

  Moreover, in each said embodiment, although the PTC (positive temperature coefficient) heater 12,121-123 is used as a heating part which heats the secondary batteries 11,111-113, it is not restricted to this, NTC (negative temperature) Coefficient) A heater may be used. In addition, when heating a secondary battery using an NTC heater, it is preferable that energization to the NTC heater is controlled at a constant current. When measuring the temperature of the secondary battery with the NTC heater, when the resistance value of the NTC heater is equal to or lower than a preset value using the resistance / temperature characteristic in which the resistance value decreases as the temperature increases. The temperature of the NTC heater is determined to be 80 ° C. or higher, and it is determined that the secondary battery 11 is abnormally heated.

  The battery temperature raising circuit and the battery temperature raising device according to the present invention can be suitably used as a device for raising the temperature of a secondary battery mounted in a device or system used in a low temperature environment.

DESCRIPTION OF SYMBOLS 11,111-113 Secondary battery 12,121-123 PTC heater 14,141-143 Switch 15 Heater control part 18 Temperature determination part

Claims (7)

A heating unit that is disposed in the vicinity of the secondary battery, heats the secondary battery, and changes its resistance value according to temperature;
A switch interposed between a power source and the heating unit;
A heating control unit that controls on / off of the switch to control heating of the secondary battery by the heating unit;
And a temperature determination unit that obtains a resistance value of the heating unit when heating of the secondary battery by the heating unit is stopped and determines a temperature of the secondary battery from the resistance value. Battery heating circuit. As the heating unit, a plurality of heating units respectively disposed in the vicinity of the plurality of secondary batteries and heating each of the plurality of secondary batteries,
As the switch, having a plurality of switches respectively interposed between the power source and the plurality of heating units,
The heating control unit controls on / off of the plurality of switches, respectively, and controls heating of the secondary battery by the plurality of heating units,
The temperature determination unit obtains a resistance value of a heating unit in which heating of the secondary battery is stopped among the plurality of heating units, and determines a temperature of the secondary battery corresponding to the heating unit from the resistance value The battery heating circuit according to claim 1.   The battery temperature increasing circuit according to claim 1, wherein the temperature determination unit obtains a resistance value of the heating unit at a preset sampling interval while heating of the secondary battery is stopped.   The battery heating circuit according to claim 1, wherein the heating unit has a positive temperature coefficient.   The battery heating circuit according to claim 1, wherein the heating unit is a PTC heater.   The battery temperature increasing circuit according to claim 4 or 5, wherein the temperature determination unit determines whether or not the resistance value is equal to or higher than a preset set value. The battery temperature increasing circuit according to any one of claims 1 to 6,
A battery temperature raising device comprising the secondary battery.

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