Charging device, disaster prevention lighting fixture, and disaster prevention lighting system

Abstract

To provide a charging device capable of extending the life of storage batteries, a disaster prevention illumination, and a disaster prevention illumination system.SOLUTION: A disclosed charging device includes: a storage battery; a charging circuit for charging the storage battery; and a control circuit that is configured so as to, when the voltage of the storage battery is greater than a predetermined threshold voltage after the charging circuit charges the storage battery to fully charged, discharge the storage battery or emit a signal to discharge the storage battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a charging device, a disaster prevention lighting device, and a disaster prevention lighting system. [Background technology]

[0002] Patent Document 1 discloses a lighting fixture for disaster prevention. The lighting device of this lighting fixture for disaster prevention includes a lighting circuit, a discharge circuit, a voltage detection circuit, and an abnormality detection circuit. The abnormality detection circuit controls the discharge circuit to discharge the battery, and performs abnormality detection processing based on the detected value when the battery voltage drops due to the start of battery discharge, or the amount of drop in the detected value before and after the battery voltage drops. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-15740 Summary of the Invention [Problem to be solved by the invention]

[0004] Battery-powered emergency lighting devices require the built-in battery to keep the light source lit for an effective period of time in an emergency. Nickel-metal hydride (Ni-MH) or nickel-cadmium (Ni-Cd) batteries are often used for the built-in batteries. Ni-MH batteries are often used in consideration of their impact on the environment.

[0005] In order to use the battery's power to illuminate a light source in an emergency, the battery is generally kept charging while commercial power is being supplied to the emergency lighting device. The positive electrode of a Ni-MH battery is beta-nickel hydroxide before charging, and becomes beta-nickel oxyhydroxide when near full charge after charging. If the battery remains fully charged and reaches an overcharged state, the positive electrode changes to gamma-nickel oxyhydroxide. At this time, the electrolyte in the separator is absorbed between the layers of the positive electrode, reducing the amount of electrolyte held by the separator. Upon discharge, the gamma-nickel oxyhydroxide returns to beta-nickel hydroxide, which is more stable in the electrolyte, via alpha-nickel hydroxide. During this change, the electrolyte absorbed by the positive electrode is released and returned to the separator.

[0006] This cycle, when carried out normally, enables the Ni-MH battery to be charged and discharged. However, if the battery remains overcharged, its internal resistance increases, and it may become unable to discharge a sufficient amount of current. The higher the charging current or the lower the temperature, the more pronounced the increase in internal resistance. Furthermore, the Technical Standard for Emergency Lighting and Evacuation Guidance Systems (JIL5502), in keeping with the Fire Service Act, does not permit intermittent charging. This can lead to trickle charging, which can further increase the internal resistance.

[0007] The Technical Standards for Emergency Lighting Equipment (JIL5501) and Technical Standards for Emergency Guide Lighting Equipment and Evacuation Guidance System Equipment (JIL5502) stipulate that storage batteries should be inspected periodically to ensure proper performance in emergencies. In Patent Document 1, abnormalities are detected based on the drop in the level of the storage battery when it is discharging. However, in Patent Document 1, it is not possible to know whether sufficient discharge is possible until the inspection is carried out. In other words, when an abnormality is detected during inspection, the storage battery is already in a state where it cannot discharge sufficiently, and it must be replaced.

[0008] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a charging device, a disaster prevention lighting fixture, and a disaster prevention lighting system that can extend the life of a storage battery. [Means for solving the problem]

[0009] A charging device according to the present disclosure includes a storage battery, a charging circuit that charges the storage battery, and a control circuit that discharges the storage battery or issues a signal to discharge the storage battery when the voltage of the storage battery is higher than a predetermined threshold voltage after the storage battery is fully charged by the charging circuit. The control circuit charges the storage battery to full charge with a first charging current, and compares the voltage of the storage battery with the threshold voltage while supplying a second charging current greater than the first charging current to the storage battery. do. [Effects of the Invention]

[0010] In the charging device according to the present disclosure, after the storage battery is fully charged, if the voltage of the storage battery is greater than a predetermined threshold voltage, the storage battery can be discharged. This allows the storage battery to be in a state where it can be discharged normally, thereby extending the life of the storage battery. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of an emergency lighting device according to a first embodiment. [Figure 2] 1 is a block diagram of a disaster prevention lighting system according to a first embodiment. [Figure 3] FIG. 10 is a diagram showing the relationship between the ambient temperature and the voltage value of the storage battery when fully charged. [Figure 4] FIG. 3 is a diagram illustrating a threshold voltage according to the first embodiment. [Figure 5] FIG. 2 is a bottom view of the emergency lighting device according to the first embodiment. [Figure 6] 5A and 5B are diagrams illustrating blinking patterns of a charge monitor LED according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A charging device, a disaster prevention lighting device, and a disaster prevention lighting system according to the present embodiment will be described with reference to the drawings. The same or corresponding components are designated by the same reference numerals, and repeated description may be omitted.

[0013] Embodiment 1 FIG. 1 is a perspective view of an emergency lighting device 100 according to a first embodiment. In this embodiment, the emergency lighting device 100 will be described as an example of a disaster prevention lighting device. The emergency lighting device 100 is also called an emergency light. The emergency lighting device 100 includes a main body 10 and mounting springs 12 extending from both side surfaces of the main body 10. The main body 10 houses a control unit 20, a light source unit 40, and a storage battery 50. The storage battery 50 is a nickel-metal hydride (Ni-MH) storage battery. The storage battery 50 is, for example, a battery pack formed by combining cells. The control unit 20 corresponds to a charging device that charges the storage battery 50. Note that in FIG. 1, the light source unit 40 and the storage battery 50 are detached from the main body 10.

[0014] FIG. 2 is a block diagram of a disaster prevention lighting system 101 according to the first embodiment. The disaster prevention lighting system 101 includes an emergency lighting fixture 100 and a cloud 70, which is an external device. The emergency light source 41 is part of the light source unit 40. In the control unit 20, the flyback circuit 21 receives power from the commercial AC power supply and supplies the power to the constant voltage circuit 22. The constant voltage circuit 22 converts the power supplied from the flyback circuit 21 to a predetermined voltage. The charging circuit 23 uses the constant voltage supplied from the constant voltage circuit 22 as a power source to charge the storage battery 50. The emergency lighting circuit 24 receives power from the storage battery 50 during inspection or in an emergency, and turns on the emergency light source 41. An emergency refers to when the commercial power supply is cut off. At this time, the power supply voltage for the microcomputer 25 is supplied from the storage battery 50.

[0015] Microcomputer 25, which is a control circuit, controls charging circuit 23, emergency lighting circuit 24, and indicator LED 30. Detection unit 26 includes voltage detection unit 26a that detects the voltage of the storage battery, and temperature measurement unit 26b that measures temperature Ta of storage battery 50. Microcomputer 25 controls charging circuit 23, emergency lighting circuit 24, and indicator LED 30 according to the detection result of detection unit 26. Microcomputer 25 also communicates with cloud 70 via communication interface 39.

[0016] For example, after 48 hours or more have passed since the commercial power AC was turned on, the microcomputer 25 measures the voltage value Vbat of the storage battery 50 when it is fully charged and the temperature Ta of the storage battery 50 using the voltage detection unit 26a and the temperature measurement unit 26b. The microcomputer 25 stores the voltage value Vbat of the storage battery 50 when it is fully charged, which corresponds to the temperature Ta of the storage battery 50, in the memory unit 25a. The memory unit 25a is, for example, a non-volatile memory. In general, the higher the temperature Ta of the storage battery 50, the lower the voltage value Vbat, and the lower the temperature Ta of the storage battery 50, the higher the voltage value Vbat. The microcomputer 25 may store the voltage value Vbat for each predetermined temperature range.

[0017] After the charging circuit 23 charges the storage battery 50 until it is fully charged, if the voltage of the storage battery 50 is higher than a predetermined threshold voltage, which will be described later, the microcomputer 25 issues a signal to discharge the storage battery 50. This causes the microcomputer 25 to instruct an external device to discharge the storage battery 50. In other words, when the voltage of the storage battery 50 reaches the threshold voltage, the microcomputer notifies an external device that there is a risk that a sufficient discharge current may not be able to flow.

[0018] After the notification, the storage battery 50 is discharged to a voltage value lower than the over-discharge prevention voltage, either by external operation or automatically. This discharge may be hereinafter referred to as recovery discharge. After the recovery discharge of the storage battery 50, the microcomputer 25 charges the storage battery 50 again.

[0019] Next, a description will be given of a method for detecting the voltage and temperature of the storage battery 50. The voltage across the storage battery 50 can be detected by having the microcomputer 25 read the voltage divided by the resistors in the voltage detection unit 26a.

[0020] The temperature Ta of the storage battery 50 can be measured by placing a temperature measurement element of the temperature measurement unit 26b inside the battery pack. The temperature measurement element is, for example, a thermistor. If it is difficult to place a temperature measurement element inside the battery pack, the temperature measurement element may be placed outside the battery pack or near the battery pack. The temperature measurement element may also be placed on the electronic circuit board of the control unit 20. The measured temperature value is read by the microcomputer 25. If the temperature Ta of the storage battery 50 cannot be measured directly, the temperature Ta of the storage battery 50 may be measured by correcting the temperature at any point inside the emergency lighting device 100. For example, the correction can be made by measuring the temperature rise value when a sample storage battery 50 is fully charged in advance.

[0021] FIG. 3 is a diagram showing the relationship between the ambient temperature and the voltage value Vbat of the storage battery 50 when fully charged. In the example of FIG. 3, the single cell voltage is shown as the voltage value Vbat when fully charged, and the ambient temperature is used as the voltage at the temperature Ta of the storage battery 50. In the example of FIG. 3, the microcomputer 25 stores voltage values ​​Vbat in 5°C increments when the temperature Ta inside the emergency lighting device 100 is in the range of -10°C to 55°C. The voltage value Vbat of the storage battery 50 when fully charged is, for example, 1.6 V / cell when the temperature Ta of the storage battery 50 is -10°C, and 1.5 V / cell when the temperature Ta is 25°C. In FIG. 3, the value when the voltage of the storage battery 50 when fully charged decreases proportionally from -10°C to 55°C is defined as the voltage value Vbat.

[0022] Next, the threshold voltage will be described. The voltage threshold is set, for example, for the same temperature range as the fully charged voltage value Vbat. That is, in the example of FIG. 3, the voltage threshold is also set in 5°C increments. The internal resistance of a normal storage battery is approximately 20 mΩ. On the other hand, it is known that the internal resistance of a Ni-MH storage battery that cannot discharge due to gamma nickel hydroxide rises to approximately 60 mΩ. In this embodiment, the increase in internal resistance is detected before discharge becomes impossible. For this reason, the microcomputer 25 sets a value lower than 60 mΩ, the internal resistance value at which discharge is impossible, as the internal resistance threshold Rth of the storage battery 50 for determining an abnormality. The internal resistance threshold Rth is, for example, 50 mΩ.

[0023] FIG. 4 is a diagram illustrating the threshold voltage according to the first embodiment. When the internal resistance of the storage battery 50 rises to the threshold Rth, assuming a charging current of 50 mA, a voltage rise of (50 mΩ - 20 mΩ) × 50 mA = 0.0015 V occurs. For example, assume that the storage battery 50 is a four-cell battery pack, the temperature Ta is between 20°C and 25°C, and the resistance of the wiring, etc. is 30 mΩ. In this case, the threshold voltage is calculated as follows: single cell voltage at temperature Ta × number of cells + charging current × (threshold Rth - normal internal resistance + wiring resistance) = 1.5143 V × 4 cells + 50 mA × (50 mΩ - 20 mΩ + 30 mΩ) ≈ 6.0614 V. This value is shown as the initial threshold voltage in FIG. 4.

[0024] In this manner, in this embodiment, if the voltage of the storage battery 50 in a fully charged state at temperature Ta is equal to or greater than the threshold voltage, it can be determined that an increase in internal resistance has occurred due to an overcharge state. The microcomputer 25 sets the threshold voltage based on the voltage value Vbat at the fully charged state corresponding to the temperature Ta of the storage battery 50. Specifically, the microcomputer 25 sets the threshold voltage based on the voltage value Vbat and the internal resistance threshold value Rth.

[0025] However, at the initial threshold voltage, the voltage increase value is small relative to the normal voltage, which is the voltage of the storage battery 50 under normal conditions, and high detection accuracy may be required. In this case, the charging current may be increased only at the timing when the voltage of the storage battery 50 is detected. This allows the increase value relative to the normal voltage to be larger. In other words, the microcomputer 25 may charge the storage battery 50 to full charge with the first charging current, and then compare the voltage of the storage battery 50 with the threshold voltage while supplying the storage battery 50 with a second charging current greater than the first charging current.

[0026] The frequency of detecting an increase in internal resistance by comparing the voltage of the storage battery 50 with the threshold voltage is preferably, for example, once every one to two weeks. The microcomputer 25 may also detect disconnection of the storage battery 50 using the voltage detection unit 26a. The threshold for detecting disconnection of the storage battery 50 is preferably set higher than the voltage threshold at the lowest temperature Ta. This can prevent erroneous determination.

[0027] Next, the notification method will be described. Fig. 5 is a bottom view of the emergency lighting device 100 according to the first embodiment. When the voltage of the storage battery 50 is higher than the threshold voltage, the microcomputer 25 issues a signal to discharge the storage battery 50 and requests an external device to recover the storage battery 50. As an example, the microcomputer 25 instructs an external device to discharge the storage battery 50 using the indicator LED 30. In this case, the signal to discharge the storage battery 50 is a signal that controls the indicator LED 30.

[0028] The indicator LED 30 is provided, for example, on the underside of the emergency lighting device 100. The indicator LED 30 includes, for example, an orange self-check monitor LED 31, a green charge monitor LED 32, and a red lamp monitor LED 33. The charge monitor LED 32 indicates the charging status of the storage battery 50. For example, the charge monitor LED 32 lights up when the storage battery 50 is charging normally, flashes twice per second when the storage battery 50 is at the end of its life or has an abnormality, and turns off when the storage battery 50 is not connected. The flashing to notify of the end of its life or an abnormality continues until the storage battery 50 is reset, for example, when it is replaced.

[0029] FIG. 6 is a diagram illustrating the blinking patterns of the charge monitor LED 32 according to the first embodiment. The upper part of FIG. 6 shows a blinking pattern that notifies the end of life or an abnormality of the storage battery 50, and the lower part shows a blinking pattern that notifies the recovery discharge. The blinking pattern of the charge monitor LED 32 that notifies the recovery discharge is, for example, a repetition of blinking once per second. In this way, the blinking pattern of the charge monitor LED 32 that requests recovery discharge is distinguished from the blinking pattern that notifies the end of life or an abnormality of the storage battery 50. Therefore, the difference between the abnormal states can be clearly seen.

[0030] As another notification method, the microcomputer 25 may send a signal to an external device to discharge the storage battery 50. The external device may be, for example, the cloud 70. Information instructing the storage battery to discharge is stored on the cloud 70 via the communication interface 39. The stored information can be obtained by an operator or a manager at any time. The disaster prevention lighting system 101 may also include a terminal such as a remote control, controller, or tablet that can communicate with the cloud 70. Once the information is stored in the cloud 70, information instructing the storage battery 50 to discharge may be transmitted from the cloud 70 to the terminal. This allows an operator or the like to immediately request that the storage battery 50 be discharged if there is a risk of malfunction.

[0031] Next, the discharge method will be described. The recovery discharge of the storage battery 50 should be performed with commercial AC power applied to continue power supply to the memory unit 25a of the microcomputer 25. As shown in FIG. 5, the emergency lighting device 100 may be provided with a recovery discharge switch 37 for discharging the storage battery 50. The microcomputer 25 discharges the storage battery 50 in response to operation of the recovery discharge switch 37. To avoid confusion with normal automatic inspection, the recovery discharge switch 37 is provided separately from the self-inspection switch 35 and inspection switch 36 used for normal inspection. The recovery discharge switch 37 may be provided as a button on a terminal such as a remote control, controller, or tablet.

[0032] The microcomputer 25 may automatically discharge the storage battery 50 when the voltage of the storage battery 50 is higher than the threshold voltage. For example, the microcomputer 25 may discharge the storage battery 50 at the same time as notifying the outside that the voltage of the storage battery 50 is higher than the threshold voltage. Furthermore, the microcomputer 25 may discharge the storage battery 50 after a predetermined period has elapsed after notifying the outside that the voltage of the storage battery 50 is higher than the threshold voltage. Furthermore, the microcomputer 25 may discharge the storage battery 50 if no recovery discharge operation is performed within a predetermined period after instructing the outside to discharge the storage battery 50. The predetermined period is, for example, one day.

[0033] Such automatic recovery discharge may be performed at night. Since there may be ordinary people in the area where the emergency lighting device 100 is installed, the storage battery 50 may be discharged to a fixed resistor provided separately from the emergency light source 41. During recovery discharge, the charge monitor LED 32 may be allowed to continue blinking to request recovery discharge. This allows an external notification that the discharge is not due to a malfunction.

[0034] In order to return the gamma nickel hydroxide to its initial state, the beta nickel hydroxide, it is effective to discharge the storage battery 50 to a voltage value lower than the overdischarge prevention voltage during recovery discharge. The voltage of the storage battery 50 after recovery discharge may be any voltage less than 1.0 V / cell, for example, 0.5 V / cell. After the storage battery 50 reaches the set voltage, the microcomputer 25 returns the storage battery 50 to a charging state.

[0035] As described above, in this embodiment, when the storage battery 50 is fully charged and the voltage of the storage battery 50 is greater than the threshold voltage, the microcomputer 25 discharges the storage battery 50 or issues a signal to discharge the storage battery 50. This allows the storage battery 50 to undergo recovery discharge when the internal resistance of the storage battery 50 increases. In other words, by returning the gamma nickel hydroxide to the initial beta nickel hydroxide state, the storage battery 50 can be made capable of normal discharge after recharging. This allows the storage battery to have a longer life.

[0036] In other words, the cycle of charging, full charging, overcharging, internal resistance increase, abnormality determination, notification, discharging, charging, etc. allows the storage battery 50 to maintain a state in which it can charge and discharge normally. Normal charging and discharging is a state in which the storage battery 50 can light the emergency light source 41 for an effective lighting time. Normally, the lifespan of a storage battery is 4 to 5 years, and it has to be replaced before the end of its lifespan. According to this embodiment, the replacement period of the storage battery 50 can be extended, significantly reducing the burden on workers.

[0037] Next, the storage and analysis of data in the cloud 70 will be described. The microcomputer 25 transmits information to the cloud 70. Data that can be detected by the emergency lighting device 100 includes the time required to reach the over-discharge prevention voltage during recovery discharge, the ambient temperature, the temperature Ta of the storage battery 50, and the voltage of the storage battery 50. This information is detected by the microcomputer 25 every one to two weeks, for example, starting 48 hours after the commercial power AC is turned on, and is stored in the cloud 70.

[0038] Based on the information accumulated in the cloud 70, workers can perform recovery discharge, analyze the accumulated data, and change the internal resistance threshold Rth. Data analysis can be performed not only by humans but also by AI. This allows for automatic detection of abnormalities in response to changing conditions. For example, suppose the initial internal resistance threshold Rth is 50 mΩ. However, analysis of the data in the cloud 70 reveals that discharge is not possible within the specified time at a threshold Rth of 50 mΩ. In this case, the AI ​​can lower the threshold Rth to, for example, 40 mΩ. The changed threshold Rth is sent to the microcontroller 25, which then rewrites the threshold Rth. Figure 4 shows an example of a threshold voltage based on a threshold Rth changed by the AI. Such setting value changes are also saved as history on the cloud 70. Workers can review this history at any time.

[0039] In addition to the threshold value Rth, the entire range of the temperature Ta of the storage battery 50, which is set to -10 to 55°C in FIG. 3, the temperature increment when setting the voltage threshold, which is set to 5°C in FIG. 3, the second charging current, the voltage of the storage battery 50 at the completion of the recovery discharge, and the like may be automatically changed by AI. This allows the recovery discharge to be performed normally. In this manner, values ​​for controlling the charging and discharging of the storage battery 50 may be set in an external device such as a cloud based on information transmitted by the microcomputer 25. The external device is not limited to a device such as the cloud 70 in which data is analyzed by AI, but may also be a device in which data is analyzed by an operator.

[0040] This embodiment is not limited to emergency lighting equipment, but can also be applied to emergency lights that use Ni-MH batteries, etc. Furthermore, the control circuit of this embodiment is not limited to a microcomputer, and may be configured with a memory unit and a processor that executes a program stored in the memory unit, etc. The control circuit may be configured with dedicated hardware.

[0041] The technical features described in this embodiment may be used in appropriate combination. [Explanation of symbols]

[0042] 10 main body, 12 mounting spring, 20 control unit, 21 flyback circuit, 22 constant voltage circuit, 23 charging circuit, 24 emergency lighting circuit, 25 microcomputer, 25a memory unit, 26 detection unit, 26a voltage detection unit, 26b temperature measurement unit, 30 display LED, 31 self-inspection monitor LED, 32 charge monitor LED, 33 lamp monitor LED, 35 self-inspection switch, 36 inspection switch, 37 recovery discharge switch, 39 communication interface, 40 light source unit, 41 emergency light source, 50 storage battery, 70 cloud, 100 emergency lighting fixture, 101 disaster prevention lighting system, AC commercial power supply,

Claims

1. A storage battery and a charging circuit for charging the storage battery; a control circuit that discharges the storage battery or issues a signal to discharge the storage battery when a voltage of the storage battery is greater than a predetermined threshold voltage after the storage battery is fully charged by the charging circuit; Equipped with The charging device is characterized in that the control circuit charges the storage battery to full charge with a first charging current, and compares the voltage of the storage battery with the threshold voltage while supplying a second charging current greater than the first charging current to the storage battery.

2. a temperature measurement unit for measuring the temperature of the storage battery; 2. The charging device according to claim 1, wherein the control circuit stores a voltage value when the storage battery is fully charged according to a temperature of the storage battery, and sets the threshold voltage based on the voltage value.

3. 3. The charging device according to claim 2, wherein the control circuit sets the threshold voltage based on the voltage value and a threshold value of the internal resistance of the storage battery for determining whether an abnormality has occurred.

4. 4. The charging device according to claim 1, wherein the control circuit issues a signal to discharge the storage battery when the voltage of the storage battery is greater than the threshold voltage, and instructs an external device to discharge the storage battery.

5. Equipped with an indicator LED, 5. The charging device according to claim 4, wherein the control circuit instructs the discharge of the storage battery by the indicator LED.

6. 5. The charging device according to claim 4, wherein the control circuit transmits a signal to an external device to cause the storage battery to discharge.

7. a switch for discharging the storage battery; 7. The charging device according to claim 1, wherein the control circuit discharges the storage battery in response to operation of the switch.

8. 7. The charging device according to claim 1, wherein the control circuit automatically discharges the storage battery when the voltage of the storage battery is higher than the threshold voltage.

9. 9. The charging device according to claim 1, wherein the control circuit charges the storage battery again after discharging the storage battery.

10. A charging device according to any one of claims 1 to 9; Emergency light source, Equipped with The charging device is provided with a lighting circuit that receives power from the storage battery and turns on the emergency light source.

11. A charging device according to any one of claims 1 to 9; an external device that sets a value for controlling charging and discharging of the storage battery based on the information transmitted by the control circuit; A disaster prevention lighting system comprising:

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