An emergency lighting system

Abstract

An emergency lighting system comprising a battery pack 100, a lighting load, an emergency driver and plug-in assembly 200. The emergency driver comprises an AC-DC converter, battery discharge circuit

Description

FIELD The present disclosure relates to the field of emergency lighting, and particularly to an emergency lighting system. BACKGROUND Currently, batteries used in the market are mostly lithium batteries. Lithium batteries have relatively high requirements for ambient temperature, and in addition, lithium batteries themselves are relatively active, posing a significant safety hazard. Conventionally, a temperature sensor is provided outside the battery pack to detect the temperature change of the battery during operation. However, it cannot represent the actual ambient temperature of the battery cells inside the battery pack. Furthermore, in the prior art, the conventional role of a temperature sensor is to detect a temperature signal, which is a single function. The disclosure of the above background art is only for assisting in understanding the concept and technical solutions of the present disclosure, and does not necessarily belong to the prior art of the present disclosure, nor does it necessarily provide technical teaching; in the absence of clear evidence that the above content has been published before the filing date of the present disclosure, the above background art should not be used to evaluate the novelty and inventiveness of the present disclosure. SUMMARY An object of the present disclosure is to provide an improved emergency lighting system that can both monitor the temperature of the battery pack and provide feedback on the connection status of the battery pack. To achieve the above object, the technical solution adopted by the present disclosure is as follows: An emergency lighting system, comprising a battery pack, a lighting load, an emergency driver, and a plug-in assembly for connecting the battery pack and the emergency driver, the emergency driver comprising an AC-DC converter, a battery discharge circuit, and a battery charging management module; wherein the plug-in assembly comprises a first plug-in member on a battery pack side and a second plug-in member on an emergency driver side, both of which are provided with at least three electrical contacts, wherein a first contact of the first plug-in member is connected to a positive electrode of the battery pack, a second contact is connected to a negative electrode of the battery pack, and a third contact is connected to the first contact or the second contact via a temperature sensor or an equivalent temperature sensing circuit; when the plug-in assembly is connected, a voltage of a contact on the second plug-in member corresponding to the third contact varies with a temperature of the battery pack; when the plug-in assembly is disconnected, the voltage of the contact on the second plug-in member corresponding to the third contact is an open-circuit voltage exceeding a range of temperature control voltage. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the second plug-in member is connected to the battery charging management module, and the emergency lighting system further comprises an indicator light electrically connected to the battery charging management module; the battery charging management module is configured to detect the voltage of the contact on the second plug-in member corresponding to the third contact, and if the open-circuit voltage is detected, the battery charging management module controls the indicator light to indicate that the battery pack is not connected. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the battery charging management module is configured to detect the voltage of the contact on the second plug-in member corresponding to the third contact, and if a detected voltage value is within a preset range of temperature control voltage, the battery charging management module turns on or adjusts a charging current for the battery pack; if the detected voltage value exceeds the preset range of temperature control voltage, the battery charging management module turns off the charging current for the battery pack. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the battery charging management module comprises a temperature control module, and the temperature control module is connected to the contact on the second plug-in member corresponding to the third contact. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the temperature control module is a microprocessor configured with a first I / O port, wherein the first I / O port is connected to the contact on the second plug-in member corresponding to the third contact, and is configured to detect the voltage of the contact via the first I / O port. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the battery charging management module further comprises a BMS module, which is connected to contacts on the second plug-in member corresponding to the first contact and the second contact, respectively, via a controllable switch; the microprocessor is further configured with a second I / O port, which is connected to a control terminal of the BMS module. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the microprocessor is further configured with a third I / O port, which is connected to the indicator light. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the microprocessor detects the voltage of the contact via the first I / O port, and if a detected voltage is within a preset range of temperature control voltage, the microprocessor instructs the BMS module via the second I / O port to turn on or adjust a charging current for the battery pack; if the detected voltage exceeds the preset range of temperature control voltage, the microprocessor instructs the BMS module via the second I / O port to turn off the charging current for the battery pack; if the detected voltage is the open-circuit voltage, the microprocessor turns off, turns on, or flashes the indicator light via the third I / O port to indicate that the battery pack is not connected. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the temperature control module is a logic gate circuit comprising a comparator. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the temperature sensor or the equivalent temperature sensing circuit is an NTC temperature sensor, which is disposed inside a battery housing of the battery pack or in an adjacent area outside the battery housing. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the battery pack further comprises a battery protection circuit, which is connected in parallel across the positive and negative electrodes of a battery cell of the battery pack. Further, in any one of the preceding technical solutions or a combination of multiple technical solutions, the battery discharge circuit comprises an emergency conversion module and a DC-DC converter, wherein the emergency conversion module comprises a first sampling circuit and a conversion switch, the first sampling circuit is configured to sample an output signal of the AC-DC converter, and the emergency conversion module turns on or off the conversion switch based on sampling results. The technical solutions provided by the present disclosure have the following beneficial effects: a. The temperature sensor is disposed inside the battery pack or on its outer wall, and the signal of the temperature sensor is led out through a third signal line to realize the monitoring of the ambient temperature inside the battery pack; b. In addition to the temperature monitoring function, the third signal line can also be used to determine whether the electrical connection of the battery pack is successful; if the battery pack is not successfully plugged into the BMS module, an indicator light connected to the MCU would indicate the current disconnected state of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the accompanying drawings required for describing the embodiments or the prior art will be briefly introduced below. It is obvious that the accompanying drawings in the following description are only some embodiments of the present disclosure, and for those of ordinary skill in the art, other drawings can be obtained from these accompanying drawings without creative effort. FIG. 1 is a schematic circuit diagram of an emergency lighting driver provided by an exemplary embodiment of the present disclosure; FIG. 2 is a schematic structural diagram of a battery pack having three output lines provided by an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION To enable those skilled in the art to better understand the solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. It is obvious that the described embodiments are only a part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort shall fall within the protection scope of the present disclosure. It should be noted that terms such as "first" and "second" in the specification and claims of the present disclosure and the above drawings are used to distinguish similar objects, and not necessarily to describe a specific order or sequence. It should be understood that the data so used can be interchanged in appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented in sequences other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to such a process, method, product, or device. In one embodiment of the present disclosure, an emergency lighting system is provided. As shown in FIG. 1, it comprises a battery pack, a lighting load, an emergency driver, and a plug-in assembly for connecting the battery pack and the emergency driver. The emergency driver comprises an AC-DC converter, a battery discharge circuit, and a battery charging management module. It is characterized in that the plug-in assembly comprises a first plug-in member on a battery pack side and a second plug-in member on an emergency driver side, both of the first plug-in member and the second plug-in member are provided with at least three electrical contacts, wherein a first contact of the first plug-in member is connected to a positive electrode of the battery pack, a second contact of the first plug-in member is connected to a negative electrode of the battery pack, and a third contact of the first plug-in member is connected to the second contact of the first plug-in member via a temperature sensor or an equivalent temperature sensing circuit. In another embodiment, the third contact of the first plug-in member is connected to the first contact of the first plug-in member via the temperature sensor or the equivalent temperature sensing circuit (not shown). The second plug-in member also has three electrical contacts. Specifically, when the first plug-in member and the second plug-in member are plugged together, the first contact of the second plug-in member is connected to the first contact of the first plug-in member, the second contact of the second plug-in member is connected to the second contact of the first plug-in member, and the third contact of the second plug-in member is connected to the third contact of the first plug-in member. When the plug-in assembly is connected, a voltage of the third contact (which is corresponding to the third contact of the first plug-in member) on the second plug-in member varies with the change in the temperature of the battery pack; when the plug-in assembly is disconnected, the voltage of the third contact on the second plug-in member is an open-circuit voltage exceeding a range of temperature control voltage. The second plug-in member is connected to the battery charging management module, and the emergency lighting system further comprises an indicator light 300 electrically connected to the battery charging management module; the battery charging management module is configured to detect the voltage of the third contact on the second plug-in member corresponding to the third contact of the first plug-in member, and if the open-circuit voltage is detected, the battery charging management module controls the indicator light to indicate that the battery pack is not connected. The battery discharge circuit comprises an emergency conversion module and a DC-DC converter, the DC-DC converter is configured to connect with the lighting load; the AC-DC converter is configured to connect with an external AC power source; the emergency conversion module comprises a first sampling circuit and a conversion switch, the first sampling circuit is configured to sample an output signal of the AC-DC converter, and the emergency conversion module controls turning on and turning off action of the conversion switch based on sampling results. The temperature sensor or the equivalent temperature sensing circuit could be an NTC temperature sensor 120, which could be disposed in the same housing together with the battery cells of the battery pack, or could be disposed in a position outside the housing adjacent to the battery pack, such as on the outer wall of the housing of the battery pack. The battery charging management module of the emergency driver comprises a BMS module and a microprocessor (MCU), and a pull-up resistor of the microprocessor constitutes a voltage divider network with the NTC temperature sensor 120. As shown in FIG. 1, an indicator light 300 is electrically connected to the microprocessor, and the microprocessor controls the indicator light 300 to turn on, turn off, or flash according to a detection result of a voltage detection circuit of the microprocessor. Specifically, a pull-up power source connecting with the pull-up resistor of the microprocessor is 3.3 V, and the voltage detected by the voltage detection circuit of the microprocessor is the voltage divided by the voltage divider network, that is, the voltage at a connection point between the pull-up resistor and the NTC temperature sensor. Therefore, when the plug-in assembly is not properly plugged in, that is, the first plug-in member is not properly plugged in the second plug-in member, or the second plug-in member is not properly plugged in the first plug-in member, the voltage divider network constituted by the pull-up resistor and the NTC temperature sensor is disconnected, and the voltage detected by the voltage detection circuit at this time is the open-circuit voltage (the value is close to 3.3 V); in other words, if the voltage value detected by the voltage detection circuit is in the range of about 3.3 V, the microprocessor controls the indicator light 300 to turn off, indicating that the battery pack 100 is not successfully connected at this time; if the voltage detected by the voltage detection circuit is not the open-circuit voltage, the indicator light is turned on to a first state. As shown in FIG. 2, the NTC temperature sensor 120 and a battery cell 110 of the battery pack are disposed in the same battery housing; the battery pack 100 further comprises a battery protection circuit 130, which is connected in parallel across the positive and negative electrodes of the battery cell 110 of the battery pack. By conventional means, when the external AC power source supplies power normally, a normal lighting driver operates to light up the lighting load; when the external AC power source fails, the output signal of the AC-DC converter is 0, and the first sampling circuit would collect a signal that the external AC power source is not connected. In this case, the emergency conversion module would turn on the conversion switch, so that an emergency lighting branch in the emergency system is connected, that is, it immediately switches to powering the lighting load by the battery pack 100. In one embodiment, the BMS module is connected with the battery pack 100 through a plug-in assembly 200. Specifically, an output terminal of the BMS module is connected to the first contact (which is corresponding to the first contact of the first plug-in member) on the second plug-in member and the second contact (which is corresponding to the second contact of the first plug-in member) on the second plug-in member respectively, via a controllable switch; and the microprocessor is connected to the third contact of the second plug-in member. The microprocessor is configured with a first I / O port, a second I / O port, and a third I / O port. The first I / O port is connected to the contact on the second plug-in member corresponding to the third contact, and is configured to detect the voltage of the contact via the first I / O port; the second I / O port is connected to a control terminal of the BMS module, that is, when the second I / O port sends an enable signal to the control terminal, the controllable switch between the BMS module and the second plug-in member is turned on; the third I / O port is connected to the indicator light. The microprocessor detects the voltage of the contact via the first I / O port. If the detected voltage is within a preset range of temperature control voltage, the microprocessor instructs the BMS module via the second I / O port to turn on or adjust a charging current for the battery pack. If the detected voltage exceeds the preset range of temperature control voltage, the microprocessor instructs the BMS module via the second I / O port to turn off the charging current for the battery pack. If the detected voltage is the open-circuit voltage, the microprocessor turns off, turns on, or flashes the indicator light via the third I / O port to indicate that the battery pack is not connected, and at this time it is definitely exceeding the preset range of temperature control voltage, and the second I / O port would not send an enable signal to the control terminal of the BMS module. In a particular embodiment, the charging of the battery pack 100 by the external AC power source could also be controlled based on the detection result of the voltage detection circuit: The NTC temperature sensor exhibits varying resistance values at different temperatures, which affects the voltage divided by the voltage divider network: the lower the temperature, the greater the resistance of the NTC temperature sensor, and the smaller the voltage value detected by the voltage detection circuit; the higher the temperature, the smaller the resistance of the NTC temperature sensor, and the larger the voltage value detected by the voltage detection circuit. Through pre-experiments, it is measured that, for example, when the ambient temperature of the battery pack 100 is at a low temperature of 0°C, the voltage value detected by the voltage detection circuit is 0.25V, and when the ambient temperature of the battery pack 100 is at a high temperature of 65°C, the voltage value detected by the voltage detection circuit is 1.75 V. The microprocessor compares the detection result of the voltage detection circuit with a preset value to determine to turn on the charging circuit or turn off it. The charging circuit is turn on by turning on the controllable switch between the BMS module and the second plug-in member, together with properly plugged in between the first plug-in member and the second plug-in member. This can be implemented by a program: if the detected voltage value is less than 0.25 V or greater than 1.75 V, the MCU sends an instruction to the BMS module through a communication unit, so that the BMS module controls the charging circuit for the battery pack 100 to be disconnected. In another embodiment, the battery charging management module of the emergency driver comprises a logic gate circuit containing a comparator to replace the microprocessor. The logic gate circuit comprises a first comparator (an op-amp device can be used), a second comparator, and a logic AND gate. The voltage detected by the voltage detection circuit is respectively connected to a positive input terminal of the first comparator and a negative input terminal of the second comparator. A negative input terminal of the first comparator is connected to 0.25 V, and a positive input terminal of the second comparator is connected to 1.75 V. Only when the voltage value detected by the voltage detection circuit is between 0.25 V and 1.75 V, both two comparators output 1. The two input terminals of the logic AND gate are connected to the output terminals of the two comparators. At this time, the logic AND gate outputs a high level to the BMS module, which is equivalent to the BMS module receiving a charging instruction, thus the charging circuit for the battery pack 100 is controlled to be conductive, which means to turn on the controllable switch. If the AND gate outputs a low level, the BMS module controls the charging circuit to be disconnected, which means to turn off the controllable switch. Specifically, the AC-DC converter comprises an input filter, a rectifier filter, and a high-frequency converter, wherein an input terminal of the input filter is connected to the external AC power source, and the rectifier filter respectively connects an output terminal of the input filter and an input terminal of the high-frequency converter; the high-frequency converter is configured to output a constant DC voltage, the high-frequency converter is connected to the BMS module through a power switch, and a duty cycle of the power switch is controlled by the BMS module. That is, when the logic AND gate outputs a low level, the BMS module controls the power switch to be turned off. As the detected voltage value gets closer to a reference voltage corresponding to 25°C to 40 °C, the duty cycle of the power switch controlled by the BMS module becomes larger. In one embodiment, the conversion switch is a MOSFET or a Silicon-controlled thyristor, and the emergency conversion module could control the duty cycle of the conversion switch in real time to achieve constant power output in the following way: A second sampling circuit is utilized to sample a current signal and a voltage signal of the lighting load, and an output terminal of the second sampling circuit is connected to the emergency conversion module; the emergency conversion module controls the duty cycle of the conversion switch based on sampling results from the second sampling circuit: an output power is calculated according to the sampled current through the lighting load and its terminal voltage. If the calculated output power is lower than a preset constant power threshold, the duty cycle of the conversion switch is controlled to increase; if the calculated output power is greater than the preset constant power threshold, the duty cycle of the conversion switch is controlled to decrease. In one embodiment of the present disclosure, an emergency lighting device is provided, comprising a lighting load, a normal lighting driver, and the emergency lighting driver as described above. It should be noted that, in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise," "include," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or device that comprises a list of elements does not include only those elements but may include other 9 elements not expressly listed or inherent to such process, method, article, or device. Without more constraints, an element preceded by the phrase "comprises a..." does not preclude the existence of additional identical elements in the process, method, article, or device that comprises the element. The foregoing descriptions are only specific embodiments of the present disclosure. It should be noted that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present disclosure, and these improvements and modifications should also be regarded as falling within the protection scope of the present disclosure.

Claims

1. An emergency lighting system, comprising a battery pack, a lighting load, an emergency driver, and a plug-in assembly for connecting the battery pack and the emergency driver, the emergency driver comprising an AC-DC converter, a battery discharge circuit, and a battery charging management module; wherein the plug-in assembly comprises a first plug-in member on a battery pack side and a second plug-in member on an emergency driver side, both of which are provided with at least three electrical contacts, wherein a first contact of the first plug-in member is connected to a positive electrode of the battery pack, a second contact is connected to a negative electrode of the battery pack, and a third contact is connected to the first contact or the second contact via a temperature sensor or an equivalent temperature sensing circuit;when the plug-in assembly is connected, a voltage of a contact on the second plug-in member corresponding to the third contact varies with a temperature of the battery pack; when the plug-in assembly is disconnected, the voltage of the contact on the second plug-in member corresponding to the third contact is an open-circuit voltage exceeding a range of temperature control voltage.

2. The emergency lighting system of claim 1, wherein the second plug-in member is connected to the battery charging management module, and the emergency lighting system further comprises an indicator light electrically connected to the battery charging management module;the battery charging management module is configured to detect the voltage of the contact on the second plug-in member corresponding to the third contact, and if the open-circuit voltage is detected, the battery charging management module controls the indicator light to indicate that the battery pack is not connected.

3. The emergency lighting system of claim 1, wherein the battery charging management module is configured to detect the voltage of the contact on the second plug-in member corresponding to the third contact, and if a detected voltage value is within a preset range of temperature control voltage, the battery charging management module turns on or adjusts a charging current for the battery pack;if the detected voltage value exceeds the preset range of temperature control voltage, the battery charging management module turns off the charging current for the battery pack.

4. The emergency lighting system of claim 2, wherein the battery charging management module comprises a temperature control module, and the temperature control module is connected to the contact onthe second plug-in member corresponding to the third contact.

5. The emergency lighting system of claim 4, wherein the temperature control module is a microprocessor configured with a first I / O port, wherein the first I / O port is connected to the contact on the second plug-in member corresponding to the third contact, and is configured to detect the voltage of the contact via the first I / O port.

6. The emergency lighting system of claim 5, wherein the battery charging management module further comprises a BMS module, which is connected to contacts on the second plug-in member corresponding to the first contact and the second contact, respectively, via a controllable switch;the microprocessor is further configured with a second I / O port, which is connected to a control terminal of the BMS module.

7. The emergency lighting system of claim 6, wherein the microprocessor is further configured with a third I / O port, which is connected to the indicator light.

8. The emergency lighting system of claim 7, wherein the microprocessor detects the voltage of the contact via the first I / O port, and if a detected voltage is within a preset range of temperature control voltage, the microprocessor instructs the BMS module via the second I / O port to turn on or adjust a charging current for the battery pack;if the detected voltage exceeds the preset range of temperature control voltage, the microprocessor instructs the BMS module via the second I / O port to turn off the charging current for the battery pack;if the detected voltage is the open-circuit voltage, the microprocessor turns off, turns on, or flashes the indicator light via the third I / O port to indicate that the battery pack is not connected.

9. The emergency lighting system of claim 4, wherein the temperature control module is a logic gate circuit comprising a comparator.

10. The emergency lighting system of claim 1, wherein the temperature sensor or the equivalent temperature sensing circuit is an NTC temperature sensor, which is disposed inside a battery housing of the battery pack orin an adjacent area outside the battery housing.

11. The emergency lighting system of claim 1, wherein the battery pack further comprises a battery protection circuit, which is connected in parallel across the positive and negative electrodes of a battery cell of the battery pack.

12. The emergency lighting system of claim 1, the battery discharge circuit comprises an emergency conversion module and a DC-DC converter, wherein the emergency conversion module comprises a first sampling circuit and a conversion switch, the first sampling circuit is configured to sample an output signal of the AC-DC converter, and the emergency conversion module turns on or off the conversion switch based on sampling results.

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