Protection circuit for low-temperature starting nickel-chromium battery

Abstract

The invention discloses a protection circuit of a low-temperature starting nickel-chromium battery. The protection circuit of the low-temperature starting nickel-chromium battery comprises a nickel-chromium battery, a first button switch, an external charging port, a current-limiting resistor, a diode, a DC bus, a first relay normally-closed contact, a relay normally-open contact, a BMS working power supply inlet, an energy storage capacitor, a temperature control switch, a relay, a heating plate, a lithium iron phosphate battery and a DC converter. A second button switch and a second relay normally-closed point; the low-temperature starting device has the advantages of simple structure and capability of realizing quick and stable starting in a low-temperature environment.

Description

Technical Field

[0001] The invention relates to the technical field of low-temperature starting of nickel-chromium batteries, and in particular to a protection circuit for low-temperature starting of nickel-chromium batteries. Background Art

[0002] The existing low-temperature mobile power supply, which contains BMS (battery management system), lithium battery and low-temperature starting battery, has the following disadvantages: 1. Due to isolation interference, the battery managed by BMS cannot directly power its own management system; 2. The existing low-temperature mobile power supply cannot be started in an environment of about -40℃; 3. The existing mobile power supply cannot meet the conditions for normal startup at any time when not used for a long time.

[0003] Therefore, a protection circuit for low-temperature starting nickel-chromium batteries is provided to solve the above problems. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing low-temperature mobile protection, the battery managed by the BMS cannot directly power its own management system, cannot be started in an environment of about -40°C, and cannot meet the condition of being able to start normally at any time when not used for a long time; therefore, a protection circuit for a low-temperature starting nickel-chromium battery is provided, and the protection circuit for a low-temperature starting nickel-chromium battery comprises: Nickel-chromium battery, first push button switch, external power supply port, current limiting resistor, diode, DC bus, first relay normally closed point, relay normally open point, BMS working power supply inlet, energy storage capacitor, temperature control switch, relay, heating plate, lithium iron phosphate battery, DC converter, second push button switch and second relay normally closed point; A first button switch, a current limiting resistor and a diode are arranged between one port of the nickel-chromium battery and the positive electrode of the DC bus, another port of the nickel-chromium battery is electrically connected to the negative electrode of the DC bus, a first relay normally closed point is connected in parallel to the current limiting resistor and the diode, and the external power supply port is connected in parallel to the nickel-chromium battery; One end of the BMS power inlet is electrically connected to the energy storage capacitor, the other end of the BMS power inlet is electrically connected to the normally open point of the relay, the normally open point of the relay is also electrically connected to the energy storage capacitor, the end of the energy storage capacitor electrically connected to the normally open point of the relay is electrically connected to the positive electrode of the DC bus, and the end of the energy storage capacitor electrically connected to the BMS power inlet is electrically connected to the negative electrode of the DC bus; The first end of the temperature-controlled switch is electrically connected to the negative pole of the DC bus, the second end of the temperature-controlled switch is electrically connected to the relay, the third end of the temperature-controlled switch is electrically connected to the relay, and the relay is electrically connected to the positive pole of the DC bus; The lithium iron phosphate battery is placed on the heating plate, the lithium iron phosphate battery is electrically connected to the DC converter, one port of the lithium iron phosphate battery is electrically connected to the positive pole of the DC bus through the normally closed point of the second relay, the other port of the lithium sulfate battery is directly electrically connected to the negative pole of the DC bus, one end of the DC converter is electrically connected to the positive pole of the DC bus through the second button switch, and the other end of the DC converter is directly electrically connected to the negative pole of the DC bus.

[0005] Furthermore, the DC bus is directly electrically connected to a number of DC users.

[0006] Furthermore, the protection circuit of the low-temperature starting nickel-chromium battery includes three working modes, including: a non-starting working mode, a heating working mode and a normal starting working mode.

[0007] Furthermore, the unstarted working mode specifically includes: the first button switch is in an open state, the first relay normally closed point is in a closed state, the relay normally open point is in an open state, the temperature control switch is in a closed state, the second button switch is in an open state, and the second relay normally closed point is in a closed state.

[0008] Furthermore, the heating working mode specifically includes: the first button switch is in a closed state, the first relay normally closed point is in a closed state, the relay normally open point is in an open state, the temperature control switch is in a closed state, the second button switch is in a closed state, and the second relay normally closed point is in a closed state.

[0009] Furthermore, the normal startup working mode specifically includes: the first button switch is in a closed state, the first relay normally closed point is in an open state, the relay normally open point is in a closed state, the temperature-controlled coffin is in an open state, the second button switch is in a closed state, and the second relay normally closed point is in an open state.

[0010] Furthermore, the rated voltage of the nickel-chromium battery is DC 24V and the rated capacity is 7AH; The resistance of the current limiting resistor is 1-2Ω; The rated capacitance of the energy storage capacitor is 0.08F; The rated voltage of the temperature control switch is DC 24V, and the temperature control switch is a normally open type greater than -20°C; The rated voltage of the heating plate is DC 24V, and the rated power is 100W; The rated voltage of the lithium iron phosphate battery is 144V DC, and the rated capacity is 30AH; The conversion range of the DC converter is DC 144V to DC 27V.

[0011] The implementation of the present invention has the following beneficial effects: 1. The present invention can realize reliable and stable starting and continuous power supply in a low-temperature environment through the coordinated use of lithium iron phosphate batteries and nickel-chromium batteries. In addition, the present invention adds an inverting diode to protect the low-temperature nickel-chromium starting battery from long-term leakage and power loss due to a complex external circuit, and adds a current limiting resistor to prevent the low-temperature nickel-chromium starting battery from being overcharged by the DC bus, and has a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a circuit diagram of the present invention in an unactivated state; Figure 2 is a circuit diagram of the heating plate of the present invention in a heating state; Figure 3 It is a circuit diagram of the present invention in a normal starting state. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0014] Please refer to the attached drawings of the specification. The technical problem to be solved in this embodiment is that the existing low-temperature mobile protection, the battery managed by the BMS cannot directly power its own management system, cannot be started in an environment of about -40°C, and cannot meet the condition of being able to start normally at any time when not used for a long time; therefore, a protection circuit for a low-temperature starting nickel-chromium battery is provided, and the protection circuit for a low-temperature starting nickel-chromium battery includes: Nickel-chromium battery 1, first push button switch 2, external power supply port 5, current limiting resistor 6, diode 7, DC bus 4, first relay normally closed point 3, relay normally open point 9, BMS working power supply inlet 8, energy storage capacitor 10, temperature control switch 11, relay, heating plate 13, lithium iron phosphate battery 14, DC converter 15, second push button switch 17 and second relay normally closed point 18; A first button switch 2, a current limiting resistor 6 and a diode 7 are arranged between one port of the nickel-chromium battery 1 and the positive pole of the DC bus 4, another port of the nickel-chromium battery 1 is electrically connected to the negative pole of the DC bus 4, a first relay normally closed point 3 is connected in parallel to the current limiting resistor 6 and the diode 7, and an external power supply port 5 is connected in parallel to the nickel-chromium battery 1; One end of the BMS power inlet is electrically connected to the energy storage capacitor 10, the other end of the BMS power inlet is electrically connected to the relay normally open point 9, the relay normally open point 9 is also electrically connected to the energy storage capacitor 10, the end of the energy storage capacitor 10 electrically connected to the relay normally open point 9 is electrically connected to the positive electrode of the DC bus 4, and the end of the energy storage capacitor 10 electrically connected to the BMS power inlet is electrically connected to the negative electrode of the DC bus 4; A first end of the temperature control switch 11 is electrically connected to the negative pole of the DC bus 4, a second end of the temperature control switch 11 is electrically connected to the relay, a third end of the temperature control switch 11 is electrically connected to the relay, and the relay is electrically connected to the positive pole of the DC bus 4; The lithium iron phosphate battery 14 is placed on the heating plate 13, and the lithium iron phosphate battery 14 is electrically connected to the DC converter 15. One port of the lithium iron phosphate battery 14 is electrically connected to the positive pole of the DC bus 4 through the normally closed point 18 of the second relay, and the other port of the lithium sulfate battery is directly electrically connected to the negative pole of the DC bus 4. One end of the DC converter 15 is electrically connected to the positive pole of the DC bus 4 through the second button switch 17, and the other end of the DC converter 15 is directly electrically connected to the negative pole of the DC bus 4.

[0015] The DC busbar 4 is directly electrically connected to a plurality of DC users 16 .

[0016] The protection circuit of the low temperature starting nickel-cadmium battery includes three working modes, including: non-starting working mode, heating working mode and normal starting working mode.

[0017] The unstarted working mode specifically includes: the first button switch is in the open state, the first relay normally closed point is in the closed state, the relay normally open point is in the open state, the temperature control switch is in the closed state, the second button switch is in the open state, and the second relay normally closed point is in the closed state.

[0018] The heating working mode specifically includes: the first button switch is in the closed state, the first relay normally closed point is in the closed state, the relay normally open point is in the open state, the temperature control switch is in the closed state, the second button switch is in the closed state, and the second relay normally closed point is in the closed state. Figure 2 , the first button switch is closed, the DC24V nickel-chromium battery is discharged, and the DC bus is energized through the normally closed point of the first relay. In the relay circuit, the temperature control switch parameter is closed when it is higher than -20℃. If the low temperature is -20℃, the relay does not work, the heating plate is energized and works, and heats the lithium iron phosphate battery.

[0019] The normal startup working mode specifically includes: the first button switch is in the closed state, the first relay normally closed point is in the open state, the relay normally open point is in the closed state, the temperature control coffin is in the open state, the second button switch is in the closed state, and the second relay normally closed point is in the open state. Figure 3When the environment around the lithium iron phosphate battery is heated to above -20℃ and reaches the operating environment temperature of the lithium iron phosphate battery, the temperature control switch is closed, the relay is energized, the normally open node of the relay is closed, the energy storage capacitor is discharged to the BMS working power supply for 1-2S, and the BMS system triggers the start of the iron phosphate battery (DC144V) to supply power, the DC converter (DC144 to DC27V) is connected to the DC bus, and the normally closed node of the first relay and the normally closed node of the second relay are opened. The DC bus (DC24V) charges the nickel-chromium battery through the diode and the current limiting resistor (1-2Ω). At the same time, the heating plate circuit is disconnected and the heating is stopped. Since there are several DC users' loads on the DC bus, the lithium iron phosphate battery heats up during power supply operation, and the temperature will continue to rise to maintain the operating temperature of the lithium iron phosphate battery.

[0020] The rated voltage of the nickel-chromium battery is DC 24V and the rated capacity is 7AH; The resistance of the current limiting resistor is 1-2Ω; The rated capacitance of the energy storage capacitor is 0.08F; The rated voltage of the temperature control switch is DC 24V, and the temperature control switch is a normally open type greater than -20℃; The rated voltage of the heating plate is DC 24V and the rated power is 100W; The rated voltage of lithium iron phosphate battery is DC 144V and the rated capacity is 30AH; The conversion range of the DC converter is DC 144V to DC 27V.

[0021] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0022] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A protection circuit for low temperature starting nickel-chromium battery, characterized in that: include: Nickel-chromium battery, first push button switch, external power supply port, current limiting resistor, diode, DC bus, first relay normally closed point, relay normally open point, BMS working power supply inlet, energy storage capacitor, temperature control switch, relay, heating plate, lithium iron phosphate battery, DC converter, second push button switch and second relay normally closed point; A first button switch, a current limiting resistor and a diode are arranged between one port of the nickel-chromium battery and the positive electrode of the DC bus, another port of the nickel-chromium battery is electrically connected to the negative electrode of the DC bus, a first relay normally closed point is connected in parallel to the current limiting resistor and the diode, and the external power supply port is connected in parallel to the nickel-chromium battery; One end of the BMS power inlet is electrically connected to the energy storage capacitor, the other end of the BMS power inlet is electrically connected to the normally open point of the relay, the normally open point of the relay is also electrically connected to the energy storage capacitor, the end of the energy storage capacitor electrically connected to the normally open point of the relay is electrically connected to the positive electrode of the DC bus, and the end of the energy storage capacitor electrically connected to the BMS power inlet is electrically connected to the negative electrode of the DC bus; The first end of the temperature-controlled switch is electrically connected to the negative pole of the DC bus, the second end of the temperature-controlled switch is electrically connected to the relay, the third end of the temperature-controlled switch is electrically connected to the relay, and the relay is electrically connected to the positive pole of the DC bus; The lithium iron phosphate battery is placed on the heating plate, the lithium iron phosphate battery is electrically connected to the DC converter, one port of the lithium iron phosphate battery is electrically connected to the positive pole of the DC bus through the normally closed point of the second relay, the other port of the lithium sulfate battery is directly electrically connected to the negative pole of the DC bus, one end of the DC converter is electrically connected to the positive pole of the DC bus through the second button switch, and the other end of the DC converter is directly electrically connected to the negative pole of the DC bus.

2. The protection circuit for low temperature starting nickel-chromium battery according to claim 1, characterized in that: The DC bus is directly connected to a number of DC users.

3. The protection circuit for low temperature starting nickel-chromium battery according to claim 2, characterized in that: The protection circuit of the low-temperature starting nickel-chromium battery includes three working modes, including: a non-starting working mode, a heating working mode and a normal starting working mode.

4. The protection circuit for low temperature starting nickel-chromium battery according to claim 3, characterized in that: The unstarted working mode specifically includes: the first button switch is in the open state, the first relay normally closed point is in the closed state, the relay normally open point is in the open state, the temperature control switch is in the closed state, the second button switch is in the open state, and the second relay normally closed point is in the closed state.

5. The protection circuit for low temperature starting nickel-chromium battery according to claim 4, characterized in that: The heating working mode specifically includes: the first button switch is in the closed state, the first relay normally closed point is in the closed state, the relay normally open point is in the open state, the temperature control switch is in the closed state, the second button switch is in the closed state, and the second relay normally closed point is in the closed state.

6. The protection circuit for low temperature starting nickel-chromium battery according to claim 5, characterized in that: The normal startup working mode specifically includes: the first button switch is in the closed state, the first relay normally closed point is in the open state, the relay normally open point is in the closed state, the temperature-controlled coffin is in the open state, the second button switch is in the closed state, and the second relay normally closed point is in the open state.

7. The protection circuit for low temperature starting nickel-chromium battery according to claim 6, characterized in that: The rated voltage of the nickel-chromium battery is DC 24V and the rated capacity is 7AH; The resistance of the current limiting resistor is 1-2Ω; The rated capacitance of the energy storage capacitor is 0.08F; The rated voltage of the temperature control switch is DC 24V, and the temperature control switch is a normally open type greater than -20°C; The rated voltage of the heating plate is DC 24V, and the rated power is 100W; The rated voltage of the lithium iron phosphate battery is 144V DC, and the rated capacity is 30AH; The conversion range of the DC converter is DC 144V to DC 27V.

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