Disaster prevention light lighting device and disaster prevention light

Abstract

To provide a disaster prevention light lighting device capable of restoring battery performance, and a disaster prevention light.SOLUTION: A disclosed disaster prevention light lighting device includes: a rechargeable battery that turns on a light source by supplying a discharge current to a light source; and a control unit that controls the discharge current so that the voltage of the rechargeable battery is maintained above a predetermined reference voltage at the recovery discharge of the rechargeable battery.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a disaster prevention lamp lighting device and a disaster prevention lamp.

Background Art

[0002] Patent Document 1 discloses an electronic device provided with a secondary battery as a power source. This electronic device includes a discharging means that consumes the power of the secondary battery to lower the voltage of the secondary battery, and executes a discharging process by itself to eliminate the voltage memory effect.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Induction lamps and emergency lamps use rechargeable batteries to light up during a power outage. In nickel-metal hydride batteries used as rechargeable batteries, it is known that the apparent capacity decreases when shallow charge and discharge cycles are repeated, which is called the memory effect. In Patent Document 1, recovery is performed by discharging against the memory effect.

[0005] On the other hand, apart from the memory effect, it has been found that when a rechargeable battery is overcharged at a low temperature for a certain period of time, the internal resistance temporarily increases. When the battery voltage drops due to the increase in internal resistance during discharge for recovery, it may be erroneously determined that the voltage for ending the discharge has been reached, and the discharge may stop. As a result, the rechargeable battery may not be fully discharged and may not be recovered. Thus, especially when the rechargeable battery is used in a low-temperature warehouse or the like, there is a possibility that it cannot light up for a specified time when emergency lighting is required.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to obtain a disaster prevention lamp lighting device and a disaster prevention lamp capable of restoring the performance of a rechargeable battery. [Means for solving the problem]

[0007] The disaster prevention light lighting device according to this disclosure comprises a rechargeable battery that supplies a discharge current to a light source to light the light source, and a control unit that controls the discharge current so that the voltage of the rechargeable battery is maintained at or above a predetermined reference voltage during the recovery discharge of the rechargeable battery. During the period in which the discharge current is controlled so that the voltage of the rechargeable battery is maintained at or above the reference voltage, the discharge current decreases and then recovers. ru. The disaster prevention light lighting device according to this disclosure comprises a rechargeable battery that supplies a discharge current to a light source to light the light source, and a control unit that controls the discharge current so that the voltage of the rechargeable battery becomes a predetermined reference voltage during the recovery discharge of the rechargeable battery, wherein the control unit controls the voltage of the rechargeable battery to become the reference voltage during the recovery discharge, and then switches the output of the rechargeable battery to constant power control. [Effects of the Invention]

[0008] In the disaster prevention light lighting device described herein, the voltage of the rechargeable battery is maintained above a predetermined reference voltage during the recovery discharge of the rechargeable battery. Therefore, the rechargeable battery can be fully discharged, and its performance can be restored. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit block diagram showing the configuration of the disaster prevention light according to Embodiment 1. [Figure 2] This diagram shows the voltage change during the discharge of a normal rechargeable battery. [Figure 3] This figure shows the voltage change during discharge of a rechargeable battery that has been overcharged at low temperatures. [Figure 4] This diagram shows the time variation of the internal resistance of a rechargeable battery. [Figure 5] This diagram shows the voltage change of a rechargeable battery when discharge is stopped at 1V. [Figure 6] This figure shows the voltage change of the rechargeable battery according to Embodiment 1. [Figure 7] This figure shows the discharge current of the rechargeable battery according to Embodiment 1. [Modes for carrying out the invention]

[0010] The disaster prevention light lighting device and disaster prevention light according to the embodiment will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repetition of the description may be omitted.

[0011] Embodiment 1. Figure 1 is a circuit block diagram showing the configuration of the disaster prevention light 100 according to Embodiment 1. The disaster prevention light 100 comprises a disaster prevention light lighting device 50 and a light source 7. The disaster prevention light 100 is also called an emergency lighting fixture. The disaster prevention light 100 is, for example, an emergency exit sign or emergency light that lights up in the event of a power outage. In Figure 1, the normal lighting circuit, inspection / self-inspection circuit, etc. are omitted.

[0012] In the disaster prevention light lighting device 50, the charging circuit 2 is powered by a commercial power source 1 to charge the rechargeable battery 3. The rechargeable battery 3 is, for example, a nickel-metal hydride battery. The rechargeable battery 3 supplies a discharge current to the light source 7 to light up the light source 7. The light source 7 is equipped with a light-emitting element such as an LED. The current control circuit 4 uses the power of the rechargeable battery 3 to supply current to the light source 7, enabling emergency lighting.

[0013] The voltage of the rechargeable battery 3 is divided by resistors 5 and 6. The connection point of resistors 5 and 6 is connected to switch 12. The current flowing through the light source 7 is detected as a voltage by sense resistor 8 and input to buffer amplifier 9. The output of buffer amplifier 9 is compared with the battery voltage supplied from switch 12 by diode 10. The cathode of diode 10 is connected to the output terminal of buffer amplifier 9, so that the lower of the battery voltage and the voltage across sense resistor 8 is applied to the - input terminal of error amplifier 11. A reference voltage 14 is applied to the + input terminal of error amplifier 11. Error amplifier 11 amplifies the difference between the reference voltage 14 and the voltage at the - input terminal and feeds it back to current control circuit 4. Based on the fed-back voltage, current control circuit 4 controls the current flowing through the light source 7.

[0014] The control circuit 13 switches the conduction and disconnection of the switch 12 according to an instruction from the recovery discharge button 15. When the control circuit 13 disconnects the switch 12, the supply of the battery voltage to the diode 10 stops. Therefore, only the voltage from the sense resistor 8 is fed back to the error amplifier 11. At this time, the current control circuit 4 controls the current of the light source 7 based on the comparison result between the voltage from the sense resistor 8 and the reference voltage 14. Therefore, the light source 7 lights up with a constant current. Note that the resistor 16 is for bias when the switch 12 is disconnected. The resistance value of the resistor 16 is set to a value that does not affect the resistors 5 and 6.

[0015] When the battery voltage drops while the switch 12 is conducting, the battery voltage is applied to the error amplifier 11. The current control circuit 4 controls the current of the light source 7 based on the comparison result between the battery voltage and the reference voltage 14. Therefore, it is controlled so that the battery voltage becomes constant.

[0016] The apparent capacity of a rechargeable battery may decrease when it repeatedly undergoes shallow charge and discharge. This is called the memory effect. The memory effect can be recovered by performing a deep discharge such as a full discharge. Also, apart from the memory effect, it has been found that when a rechargeable battery is overcharged at low temperature for a certain period, its internal resistance temporarily increases. General induction lamps and emergency lights are designed to continue trickle charging while the commercial power supply is on. Therefore, overcharging cannot be avoided. As the rechargeable battery 3, for example, a dedicated rechargeable battery that can withstand overcharging is used. The phenomenon of a temporarily increased internal resistance was found during the improvement for enhancing the performance of such a rechargeable battery 3.

[0017] To recover such an increase in internal resistance, a special deep discharge is not necessary, and normal discharge is sufficient. However, due to the voltage drop associated with the increase in internal resistance, the battery voltage decreases. Therefore, during the discharge for recovery, it may be erroneously determined that the discharge reference voltage has been reached, and the discharge may stop. Thus, if the rechargeable battery is used in a low-temperature warehouse or the like, there is a risk that the performance of the rechargeable battery cannot be recovered. In this case, when emergency lighting is required, there is a risk that the rechargeable battery cannot provide power for the specified time.

[0018] In general, inspection and self-inspection functions for inspecting rechargeable batteries are provided for emergency lights and evacuation lights. Since these inspection functions are for checking the life of rechargeable batteries, they discharge only up to a predetermined voltage under predetermined output conditions. Therefore, similar to the discharge for recovery described above, it is assumed that the discharge is stopped due to the voltage drop associated with the increase in internal resistance, and the internal resistance cannot be recovered.

[0019] FIG. 2 is a diagram showing the voltage change during discharge of a normal rechargeable battery. It takes more than 60 minutes for a normal rechargeable battery to reach the discharge reference voltage of 1.0V. Here, the discharge reference voltage is the voltage at which the discharge is stopped. FIG. 3 is a diagram showing the voltage change during discharge of a rechargeable battery overcharged at low temperature. The battery voltage of a rechargeable battery overcharged at low temperature drops below 1.0V once every approximately 5 minutes. Therefore, there is a risk of misjudgment that the voltage at which the discharge should be terminated has been reached at this point in the normal inspection and self-inspection functions. At this time, the charge of the rechargeable battery remains, and if the discharge cannot be stopped, the discharge can continue. Note that FIG. 3 shows the voltage change when the discharge is continued without stopping at 1.0V.

[0020] FIG. 4 is a diagram showing the change in the internal resistance of a rechargeable battery over time. FIG. 4 shows the difference in the internal resistance between the normal rechargeable battery of FIG. 2 and the rechargeable battery overcharged at low temperature of FIG. 3. The internal resistance shown in FIG. 4 does not include the resistance value that a normal rechargeable battery originally has. It can be seen from FIG. 4 that the internal resistance decreases in a relatively short time of about 25 minutes of discharge and returns to a normal state.

[0021] FIG. 5 is a diagram showing the voltage change of a rechargeable battery when the discharge is stopped at 1V. When the discharge is stopped when the battery voltage reaches 1V, as in the inspection and self-inspection functions of normal emergency lights and evacuation lights, the recovery does not progress until the internal resistance decreases. When the discharge is stopped, the battery voltage returns to the open-circuit voltage and becomes, for example, about 1.2V.

[0022] In contrast, the disaster prevention light 100 of this embodiment has a recovery discharge function to restore the rechargeable battery 3, in addition to the inspection and self-inspection functions. The inspection, self-inspection function and the recovery discharge function will be described below. First, the inspection function is a function that illuminates the light in an emergency if the battery voltage is above the discharge reference voltage, for example, while an inspection switch (not shown) is pressed. If the battery voltage falls below the discharge reference voltage while the inspection switch is pressed, the control circuit 13 detects a battery abnormality and turns off the light source 7.

[0023] Next, the self-check function is a function that, for example, if a self-check switch (not shown) is pressed and held, the light source 7 will be illuminated in an emergency for a specified period of time. The control circuit 13 will complete the self-check normally if the battery voltage is above the discharge reference voltage during the specified period. If the battery voltage falls below the discharge reference voltage before the specified period has elapsed, the control circuit 13 will terminate the emergency illumination and display a battery abnormality on the display unit (not shown). The self-check function can only be used if the rechargeable battery 3 has been continuously charged for a certain period of time, such as 24 hours or 48 hours.

[0024] The inspection and self-check function is a function for determining the performance of the rechargeable battery 3. Therefore, it is assumed that the light source 7 is lit with the required light output. For this reason, the light source 7 lights up at a brightness above a certain level, and the load becomes constant power.

[0025] Next, the recovery discharge function will be explained. Hereafter, the current control circuit 4, resistors 5 and 6, sense resistor 8, buffer amplifier 9, diode 10, error amplifier 11, switch 12, and control circuit 13 may be referred to as the control unit. During recovery discharge, the control unit controls the discharge current so that the battery voltage of the rechargeable battery 3 becomes a voltage corresponding to a predetermined reference voltage 14. The voltage corresponding to the reference voltage 14 is set higher than the discharge reference voltage that stops the discharge of the rechargeable battery 3.

[0026] In other words, the recovery discharge function prevents the discharge from stopping by adjusting the discharge current of the rechargeable battery 3 and maintaining the battery voltage above the discharge reference voltage. This allows the rechargeable battery 3 to be fully discharged. It also restores the internal resistance of the rechargeable battery 3. Therefore, it is possible to restore the performance of the rechargeable battery 3. This prevents unnecessary battery replacement and insufficient illumination time of the light source 7 when needed.

[0027] The recovery discharge function can be activated by operating the recovery discharge button 15. During recovery discharge, the control circuit 13 conducts to the switch 12 in response to the instruction from the recovery discharge button 15. When not in recovery discharge mode, the control circuit 13 releases the switch 12 in response to the instruction from the recovery discharge button 15. This allows the recovery discharge function to be turned ON / OFF.

[0028] Figure 6 shows the voltage change of the rechargeable battery 3 according to Embodiment 1. Figure 7 shows the discharge current of the rechargeable battery 3 according to Embodiment 1. In Figures 6 and 7, the horizontal axis represents the elapsed time from the start of discharge. When the recovery discharge button 15 is pressed, the control circuit 13 conducts the switch 12. The current control circuit 4 also causes the rechargeable battery 3 to recover discharge. At this time, the voltage of the rechargeable battery 3 decreases as shown in Figure 6.

[0029] Immediately after the start of discharge, the battery voltage is high, so the voltage across the sense resistor 8 is applied to the error amplifier 11. As a result, the light source 7 is controlled to a constant current immediately after the start of discharge, and the battery voltage drops rapidly. At this time, the rechargeable battery 3 is outputting a constant power. Here, the voltage corresponding to the reference voltage 14 is set to 1.05V. The battery voltage reaches 1.05V about 6 minutes after the start of discharge. As a result, the battery voltage is applied to the error amplifier 11, and the rechargeable battery 3 switches to constant voltage operation. In Figure 6, the battery voltage is maintained constant for a period from 6 to 17 minutes.

[0030] As shown in Figure 7, the discharge current from the rechargeable battery 3 increases in proportion to the decrease in battery voltage for the first 6 minutes from the start of discharge, as it is a constant power output. During constant voltage operation from 6 to 17 minutes, the discharge current decreases sharply in order to maintain the battery voltage. The decrease in discharge current reduces the voltage drop due to the internal resistance of the rechargeable battery 3, and as a result, the battery voltage of the rechargeable battery 3 is maintained.

[0031] As time passes and the internal resistance decreases, the discharge current recovers. After about 17 minutes, the internal resistance recovers and the battery voltage becomes higher than the voltage across the sense resistor 8. As a result, the voltage across the sense resistor 8 is applied to the error amplifier 11, and the voltage and current waveform return to that of the constant power output. In this way, the control unit controls the battery voltage of the rechargeable battery 3 to match the voltage of the reference voltage 14 during the recovery discharge, and then switches the output of the rechargeable battery 3 to constant power control.

[0032] In this embodiment, if the battery voltage drops due to internal resistance, the discharge current is reduced to adjust the battery voltage so that it becomes equal to or greater than the voltage corresponding to the reference voltage 14. This allows the discharge to continue and the performance of the rechargeable battery 3 to be restored even if the internal resistance temporarily increases. However, in the recovery discharge of this embodiment, the output of the rechargeable battery 3 is not constant power, and the discharge is performed with less power than during normal inspection. For this reason, the rechargeable battery 3 cannot be inspected.

[0033] Furthermore, during constant power control from 17 minutes after the start of discharge, the control unit stops discharging when the battery voltage reaches the discharge reference voltage. This prevents over-discharging of the rechargeable battery 3. In Figure 6, the control unit stops discharging when the voltage drops from 75 minutes after the start of discharge.

[0034] Recovery discharge is completed in a short time. Therefore, if the battery does not switch from constant voltage control after a predetermined time has elapsed since the start of discharge, it can be determined that the battery 3 has reached the end of its lifespan. The predetermined time is, for example, 30 minutes. In other words, constant voltage control is not required after 30 minutes from the start of discharge. The control unit may issue an external notification if it does not switch to constant power control after a predetermined time has elapsed since the start of recovery discharge.

[0035] The predetermined time required for recovery discharge may be determined appropriately according to the environment in which the rechargeable battery 3 and the disaster prevention light 100 are used. The control unit may determine that the rechargeable battery 3 has reached the end of its lifespan if the internal resistance does not decrease even after a predetermined time has elapsed, that is, if the discharge current remains below a specified value even after a predetermined time has elapsed.

[0036] During constant voltage control, the battery voltage is maintained at a voltage higher than the discharge reference voltage. However, if the lifespan is satisfactory according to the characteristics of the rechargeable battery 3, the battery voltage may be lowered below the discharge reference voltage for a short period during constant voltage control. The battery voltage during constant voltage control should be determined appropriately according to the type of rechargeable battery 3 and the environment in which the disaster prevention light 100 is used.

[0037] The control unit of this embodiment includes an analog circuit. However, it is not limited to this; functions such as the buffer amplifier 9, diode 10, error amplifier 11, and switch 12 may be realized by digital circuits using a microcontroller or the like. In this case, the voltage values ​​from resistors 5, 6, and sense resistor 8 are input to the microcontroller via A / D conversion, and the current control circuit 4 can be controlled by the microcontroller's software. This simplifies the circuit. As the control unit, any circuit capable of controlling the discharge current so that the battery voltage of the rechargeable battery 3 is maintained above a predetermined voltage during recovery discharge can be used.

[0038] The instruction for recovery discharge is not limited to the operation of the recovery discharge button 15; it may also be instructed via communication from a remote control or the like. Furthermore, the recovery discharge button 15 may also be used in conjunction with a switch that has another function. For example, recovery discharge may be performed by long-pressing a switch with another function.

[0039] The technical features described in this embodiment may be used in combination as appropriate.

[0040] The various aspects of this disclosure are summarized below as an appendix. (Note 1) A rechargeable battery that supplies a discharge current to a light source to light up the light source, A control unit controls the discharge current so that the voltage of the rechargeable battery is maintained at or above a predetermined reference voltage during the recovery discharge of the rechargeable battery. A disaster prevention light lighting device characterized by being equipped with the following features. (Note 2) The disaster prevention light lighting device according to Appendix 1, characterized in that the reference voltage is set higher than the discharge reference voltage for stopping the discharge of the rechargeable battery. (Note 3) The disaster prevention light lighting device according to Appendix 1 or 2, characterized in that the control unit controls the discharge current during the recovery discharge so that the voltage of the rechargeable battery becomes the reference voltage. (Note 4) The disaster prevention light lighting device according to Appendix 3, characterized in that the control unit controls the voltage of the rechargeable battery to become the reference voltage during the recovery discharge, and then switches the output of the rechargeable battery to constant power control. (Note 5) The disaster prevention light lighting device according to Appendix 4, characterized in that the control unit notifies an external party if a predetermined time has elapsed since the start of the recovery discharge and the control unit has not switched to constant power control. (Note 6) A disaster prevention light lighting device as described in any one of the items 1 to 5, The aforementioned light source, A disaster prevention light characterized by having the following features. [Explanation of symbols]

[0041] 1. Commercial power supply, 2. Charging circuit, 3. Rechargeable battery, 4. Current control circuit, 5, 6. Resistors, 7. Light source, 8. Sense resistor, 9. Buffer amplifier, 10. Diode, 11. Error amplifier, 12. Switch, 13. Control circuit, 14. Reference voltage, 15. Recovery discharge button, 50. Emergency light ignition device, 100. Emergency light

Claims

1. A rechargeable battery that supplies a discharge current to a light source to light up the light source, A control unit controls the discharge current so that the voltage of the rechargeable battery is maintained at or above a predetermined reference voltage during the recovery discharge of the rechargeable battery. Equipped with, A disaster prevention light lighting device characterized in that, during the period in which the discharge current is controlled so that the voltage of the rechargeable battery is maintained at or above the reference voltage, the discharge current decreases and then recovers.

2. The disaster prevention light lighting device according to claim 1, characterized in that the reference voltage is set higher than the discharge reference voltage for stopping the discharge of the rechargeable battery.

3. The disaster prevention light lighting device according to claim 1 or 2, characterized in that the control unit controls the discharge current during the recovery discharge so that the voltage of the rechargeable battery becomes the reference voltage.

4. A rechargeable battery that supplies a discharge current to a light source to light up the light source, A control unit controls the discharge current during the recovery discharge of the rechargeable battery so that the voltage of the rechargeable battery becomes a predetermined reference voltage, Equipped with, The disaster prevention light lighting device is characterized in that, during the recovery discharge, the control unit controls the voltage of the rechargeable battery to become the reference voltage, and then switches the output of the rechargeable battery to constant power control.

5. The disaster prevention light lighting device according to claim 4, characterized in that the control unit notifies an external party if a predetermined time has elapsed since the start of the recovery discharge and the control unit has not switched to the constant power control.

6. A disaster prevention light lighting device according to any one of claims 1, 2, 4, or 5, The aforementioned light source, A disaster prevention light characterized by having the following features.

Images