A sodium battery pack low temperature charging current limiting circuit, device and control method

Abstract

The invention discloses a sodium battery pack low-temperature charging current limiting circuit, device and control method, comprising: a generator, a temperature control module and a constant current source; when the temperature of the sodium battery pack is higher than a temperature threshold, the temperature control module is turned on, so that the other end of the generator passes through the temperature control module to charge the sodium battery pack; when the temperature of the sodium battery pack is lower than the temperature threshold, the temperature control module is turned off, so that the other end of the generator passes through the constant current source module to charge the sodium battery pack, and the constant current source module is used to dissipate heat to heat the sodium battery pack; by using the sodium battery pack low-temperature charging current limiting circuit disclosed in the invention, when the temperature of the sodium battery pack is too low, the constant current source module is used to reduce the charging current of the sodium battery pack, and the heat dissipated by the constant current source is used to heat the sodium battery pack at a low temperature, so that the temperature of the sodium battery pack can be quickly increased, the charging efficiency of the sodium battery pack is improved, and the sodium battery pack can be prevented from being damaged by charging with a large current in a low-temperature state.

Description

Technical Field

[0001] The present invention relates to the technical field of battery protection, and in particular to a sodium battery pack low-temperature charging current limiting circuit, device and control method. Background Art

[0002] In the prior art, the operation of sodium batteries depends on the electrochemical reactions inside the battery, especially the embedding and extraction process of sodium ions between the positive and negative electrodes. In a low temperature environment, the migration speed of sodium ions slows down, and the conductivity of the electrolyte also decreases, resulting in a decrease in the reaction efficiency inside the battery. At this time, if a large current is charged, the sodium ions may not be able to embed into the electrode material in time, which may easily lead to severe polarization of the battery, affecting the charging efficiency and even damaging the battery.

[0003] The electrochemical reaction of sodium batteries is not active in low temperature environments, and the charging efficiency is inherently low. If a large current is used for charging, most of the energy may be converted into heat waste, which is not conducive to the effect of battery charging. Summary of the invention

[0004] The purpose of the present invention is to disclose a sodium battery pack low temperature charging current limiting circuit, device and control method, which solves the problem that the existing sodium battery uses a large current to charge in a low temperature environment, which affects the charging efficiency and even damages the battery.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A sodium battery pack low-temperature charging current limiting circuit comprises: a generator for charging the sodium battery pack, a temperature control module for turning on or off according to the temperature of the sodium battery pack, and a constant current source for controlling the charging current of the sodium battery pack and providing heat to the sodium battery pack; one end of the generator is electrically connected to the positive electrode of the sodium battery pack; the other end of the generator is electrically connected to the negative electrode of the sodium battery pack through the temperature control module; the other end of the generator is electrically connected to the negative electrode of the sodium battery pack through the constant current source module; when the temperature of the sodium battery pack is higher than a temperature threshold, the temperature control module is turned on so that the other end of the generator charges the sodium battery pack through the temperature control module; when the temperature of the sodium battery pack is lower than the temperature threshold, the temperature control module is turned off so that the other end of the generator charges the sodium battery pack through the constant current source module, and the sodium battery pack is heated and heated by dissipating heat from the constant current source module.

[0007] In one embodiment, the temperature control module includes: a temperature control switch, a vibration sensor, a first transistor and a relay unit; the positive electrode of the generator is electrically connected to the negative electrode of the generator through the temperature control switch and the vibration sensor in sequence; the output end of the vibration sensor is electrically connected to the base of the first transistor; the emitter of the first transistor is electrically connected to the constant current source module; the emitter of the first transistor is also electrically connected to the positive electrode of the generator through the temperature control switch; the collector of the first transistor is electrically connected to the negative electrode of the generator through the control end of the relay unit; the negative electrode of the generator is also electrically connected to the negative electrode of the sodium battery pack through the controlled end of the relay unit.

[0008] In one embodiment, the temperature control module also includes: a first resistor, a second resistor and a first diode; the base of the first transistor is electrically connected to the emitter of the first transistor after passing through the first resistor; the base of the first transistor is electrically connected to the output end of the vibration sensor after passing through the second resistor; the cathode of the first diode is electrically connected to the collector of the first transistor; and the anode of the first diode is electrically connected to the negative pole of the generator.

[0009] In one embodiment, the constant current source module includes: a second triode, a third resistor, a fifth resistor, a sixth resistor and at least one shunt heating unit; the collector of the second triode is electrically connected to the emitter of the first triode through the third resistor; the collector of the second triode is also electrically connected to the control end of the shunt heating unit; the base of the second triode is electrically connected to the current detection end of the shunt heating unit through the fifth resistor; the base of the second triode is electrically connected to the negative pole of the generator through the sixth resistor; the emitter of the second triode is electrically connected to the negative pole of the generator; the input end of the shunt heating unit is electrically connected to the negative pole of the sodium battery pack; the output end of the shunt heating unit is electrically connected to the negative pole of the generator; when the temperature of the sodium battery pack is lower than the temperature threshold, the temperature control module is turned off, and the shunt heating unit dissipates heat when the charging current passes through it, which is used to heat the sodium battery pack.

[0010] In one embodiment, the shunt heating unit includes: a fourth resistor, a MOS tube, a seventh resistor, and a third diode; the gate of the MOS tube is electrically connected to the collector of the second triode through the fourth resistor; the drain of the MOS tube is electrically connected to the negative electrode of the sodium battery pack; the source of the MOS tube is electrically connected to the negative electrode of the generator through the seventh resistor; the source of the MOS tube is also electrically connected to the anode of the third diode; the cathode of the third diode is electrically connected to the base of the second triode through the fifth resistor; when the temperature of the sodium battery pack is lower than the temperature threshold, the temperature control module is turned off, and the MOS tube and the seventh resistor dissipate heat when the charging current passes through, so as to heat the sodium battery pack.

[0011] In one embodiment, the constant current source module further includes: a voltage stabilizing diode; an anode of the voltage stabilizing diode is electrically connected to the negative electrode of the generator; and a cathode of the voltage stabilizing diode is electrically connected to the collector of the second transistor.

[0012] In one embodiment, it further includes: a filter module; two ends of the filter module are electrically connected to the positive pole of the generator and the negative pole of the generator respectively.

[0013] In one embodiment, the generator has a voltage regulator and an excitation coil inside.

[0014] A sodium battery pack low temperature charging current limiting circuit control method is applied to the above sodium battery low temperature charging current limiting circuit, the method comprising:

[0015] Obtaining the temperature of the sodium battery pack, and determining whether the temperature of the sodium battery pack is greater than a temperature threshold;

[0016] If yes, the temperature control module is controlled to be turned on so that the generator can directly charge the sodium battery pack through the temperature control module;

[0017] If not, the temperature control module is controlled to be turned off so that the generator charges the sodium battery pack through the constant current source module, and the heat generated by the constant current source module when it is working is used to heat the sodium battery pack; when the temperature of the sodium battery pack is higher than the temperature threshold, the temperature control module is controlled to be turned on again so that the generator directly charges the sodium battery pack through the temperature control module.

[0018] A sodium battery pack low temperature charging current limiting device comprises: a sodium battery pack and the above-mentioned sodium battery pack low temperature charging current limiting circuit; the sodium battery pack is electrically connected to the sodium battery pack low temperature charging current limiting circuit.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a sodium battery pack low temperature charging current limiting circuit, device and control method, comprising: a generator, a temperature control module and a constant current source; one end of the generator is electrically connected to the positive electrode of the sodium battery pack; the other end of the generator is electrically connected to the negative electrode of the sodium battery pack through the temperature control module; the other end of the generator is electrically connected to the negative electrode of the sodium battery pack through the constant current source module; when the temperature of the sodium battery pack is higher than a temperature threshold, the temperature control module is turned on, so that the other end of the generator charges the sodium battery pack through the temperature control module; when the temperature of the sodium battery pack is lower than the temperature threshold, the temperature control module is turned off, so that the other end of the generator charges the sodium battery pack through the constant current source module, and the constant current source module is used to dissipate heat to heat the sodium battery pack; in summary, by using the sodium battery pack low temperature charging current limiting circuit disclosed in the present invention, when the temperature of the sodium battery pack is too low, the constant current source module is used to reduce the charging current of the sodium battery pack, and the heat dissipated by the constant current source is used to heat the sodium battery pack at a low temperature, so that the temperature of the sodium battery pack can be quickly increased, the charging efficiency of the sodium battery pack is improved, and the sodium battery pack can be prevented from being damaged by charging with a large current at a low temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0022] Figure 1 This is a schematic diagram of a low-temperature charging current limiting circuit for a sodium battery pack of the present invention;

[0023] Figure 2 is a circuit schematic diagram of a constant current source module according to an embodiment of the present invention;

[0024] Figure 3 This is a circuit diagram of another constant current source module in an embodiment of the present invention.

[0025] In the figure, 1, sodium battery pack; 2, generator; 3, temperature control module; 4, constant current source module; 401, shunt heating unit. DETAILED DESCRIPTION

[0026] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0027] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. The terms "vertical", "horizontal", "left", "right", "above", "below" and similar expressions are for illustrative purposes only, 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 limiting the present invention.

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Embodiment 1

[0030] like Figure 1 , 2A low-temperature charging current limiting circuit for a sodium battery pack 1 is shown, comprising: a generator 2 for charging the sodium battery pack 1, a temperature control module 3 for turning on or off according to the temperature of the sodium battery pack 1, and a constant current source for controlling the charging current of the sodium battery pack 1 and providing heat to the sodium battery pack 1; one end of the generator 2 is electrically connected to the positive electrode of the sodium battery pack 1; the other end of the generator 2 is electrically connected to the negative electrode of the sodium battery pack 1 through the temperature control module 3; the other end of the generator 2 is electrically connected to the negative electrode of the sodium battery pack 1 through the constant current source module 4; when the temperature of the sodium battery pack 1 is higher than the temperature threshold, the temperature control module 3 is turned on so that the other end of the generator 2 charges the sodium battery pack 1 through the temperature control module 3; when the temperature of the sodium battery pack 1 is lower than the temperature threshold, the temperature control module 3 is turned off so that the other end of the generator 2 charges the sodium battery pack 1 through the constant current source module 4, and the constant current source module 4 is used to dissipate heat to heat the sodium battery pack 1.

[0031] Specifically, in actual use, the operation of sodium batteries depends on the electrochemical reactions inside the battery, especially the embedding and extraction process of sodium ions between the positive and negative electrodes. In a low temperature environment, the migration speed of sodium ions slows down, and the conductivity of the electrolyte also decreases, resulting in a decrease in the reaction efficiency inside the battery. At this time, if a large current is charged, the sodium ions may not be able to embed into the electrode material in time, which may easily lead to serious battery polarization, affect the charging efficiency and even damage the battery. Although sodium batteries are not as prone to forming lithium dendrites as lithium batteries, fast charging in a low temperature environment may still cause similar problems. If the charging current is too large, the sodium ions cannot be evenly embedded in the negative electrode, and sodium deposits may form on the surface of the electrode. These deposits may gradually grow to form tiny sodium dendrites, which then pierce the battery separator, causing an internal short circuit, which may cause safety problems in severe cases. Therefore, how to safely charge sodium batteries at lower temperatures is a problem that needs to be solved by technicians in this field. In order to charge the low-temperature sodium battery pack 1, the present application uses a temperature control module 3 and a constant current source module 4 in parallel to connect the generator 2 and the sodium battery pack 1. When the temperature control module 3 detects that the temperature of the sodium battery pack 1 is high, the temperature control module 3 is turned on and the constant current source module 4 is short-circuited, allowing the generator 2 to directly charge the sodium battery pack 1. When the temperature of the sodium battery pack 1 is low, the temperature control module 3 is turned off, and the generator 2 can only charge the sodium battery pack 1 through the constant current source module 4. The constant current source module 4 can limit the current output by the generator 2 to the sodium battery pack 1, and the components in the constant current source are While regulating the current to generate a voltage drop, heat will be dissipated. By adjusting the physical distance between the constant current source module 4 and the sodium battery group 1 module, the heat generated by the constant current source module 4 can be used to heat the sodium battery group 1, so that the temperature of the sodium battery group 1 can be quickly increased. When the temperature of the sodium battery group 1 increases, the temperature control module 3 is turned on, and the generator 2 directly charges the sodium battery group 1 through the temperature control module 3, so that the sodium battery group 1 can be charged at full power, achieving a balance between the service life of the sodium battery group 1 and the charging efficiency of the sodium battery group 1, and avoiding the danger of the sodium battery group 1 being damaged due to low-temperature and high-current charging.

[0032] Specifically, in the present application, the temperature threshold is selected as 0°C. When the temperature is higher than 0°C, the temperature control module 3 is turned on, and when the temperature is lower than 0°C, the temperature control module 3 is turned off.

[0033] In one embodiment, the temperature control module 3 includes: a second diode D2, a temperature control switch K, a vibration sensor G, a first transistor Q1 and a relay unit J;

[0034] The positive electrode of the generator 2 is electrically connected to the negative electrode of the generator 2 through the temperature control switch K and the vibration sensor G in sequence;

[0035] The output end of the vibration sensor G is electrically connected to the base of the first transistor Q1;

[0036] The emitter of the first transistor Q1 is electrically connected to the constant current source module 4; the emitter of the first transistor Q1 is also electrically connected to the positive electrode of the generator 2 through the temperature control switch K;

[0037] The collector of the first transistor Q1 is electrically connected to the negative electrode of the generator 2 through the control end of the relay unit J; the negative electrode of the generator 2 is also electrically connected to the negative electrode of the sodium battery group 1 through the controlled end of the relay unit J;

[0038] The anode of the second diode D2 is electrically connected to the negative electrode of the generator 2 ; the cathode of the second diode D2 is electrically connected to the negative electrode of the sodium battery group 1 .

[0039] Specifically, in a low temperature environment, the car will not only be in a stationary state, but also in a driving state. Therefore, it is necessary not only to consider limiting the charging current of the car, but also to ensure that the battery discharge will not be affected when the car is in a driving state. Therefore, the temperature control module 3 includes a vibration sensor G, and the relay unit in the present application is a normally closed relay, that is, when the signal input end of the relay is not energized, the switch part of the relay is closed, and when the signal input end of the relay is energized, the switch part of the relay is disconnected. The control end of the relay unit in the present application is the part of the relay unit that receives the control signal, and the controlled end of the relay unit is the switch part that is turned on or off by the control signal.

[0040] When the temperature is lower than the temperature threshold and the vehicle is stationary, the temperature control switch K is closed, and the vibration sensor G and the relay unit start to operate under the action of the sodium battery pack 1; since the vehicle has no vibration, the vibration sensor G outputs a high potential, the first transistor Q1 is turned off, the control end of the relay is turned off, and the controlled end JK of the relay unit is closed, and the energy of the sodium battery pack 1 can be smoothly output to the P-port, and the car engine can be started with a large current.

[0041] When the temperature is lower than the temperature threshold and the vehicle is in the engine running state, the temperature control switch K is closed, and the vibration sensor G and the relay unit start to operate under the action of the sodium battery pack 1; the vibration of the engine operation causes the output end of the vibration sensor G to output a low level, the first transistor Q1 is turned on, the control end of the relay is energized to a high level, the controlled end of the relay unit is disconnected, and the energy of the sodium battery pack 1 is output through the second diode D2.

[0042] By using the temperature control module 3 in the present application, it is possible to ensure that the electric energy in the sodium battery pack 1 is smoothly output regardless of whether the vehicle is running or not.

[0043] In one embodiment, the temperature control module 3 also includes: a first resistor R1, a second resistor R2 and a first diode D1; the base of the first transistor Q1 is electrically connected to the emitter of the first transistor Q1 after passing through the first resistor R1; the base of the first transistor Q1 is electrically connected to the output end of the vibration sensor G after passing through the second resistor R2; the cathode of the first diode D1 is electrically connected to the collector of the first transistor Q1; the anode of the first diode D1 is electrically connected to the negative electrode of the generator 2.

[0044] When the relay coil is powered off, a self-induced electromotive force will be generated in the coil due to the characteristics of inductance. This self-induced electromotive force will generate a large reverse current shock at the moment the relay is powered off, which may damage the coil or other sensitive electronic components. The first diode D1 is connected in parallel at both ends of the relay coil. Its function is to act as a freewheeling diode. When the relay coil is powered off, it provides a reverse current path to prevent the self-induced electromotive force from causing shock or damage to other circuits. It can effectively protect the relay coil and other components in the control circuit from reverse voltage shocks, extend the life of the relay, and prevent instability problems caused by reverse current in the circuit. The first diode D1 dissipates the self-induced voltage by providing a low-impedance path for the reverse current to prevent voltage surges from damaging components.

[0045] In one embodiment, the constant current source module 44 includes: a second triode Q3, a third resistor R3, a fifth resistor R5, a sixth resistor R6 and at least one shunt heating unit 401; the collector of the second triode Q3 is electrically connected to the emitter of the first triode Q1 through the third resistor R3; the collector of the second triode Q3 is also electrically connected to the control end of the shunt heating unit 401; the base of the second triode Q3 is electrically connected to the current detection end of the shunt heating unit 401 through the fifth resistor R5; the base of the second triode Q3 is electrically connected to the negative electrode of the generator 2 through the sixth resistor R6; the emitter of the second triode Q3 is electrically connected to the negative electrode of the generator 2; the input end of the shunt heating unit 401 is electrically connected to the negative electrode of the sodium battery pack 1; the output end of the shunt heating unit 401 is electrically connected to the negative electrode of the generator 2; when the temperature of the sodium battery pack 1 is lower than the temperature threshold, the temperature control module 3 is turned off, and the shunt heating unit 401 dissipates heat when the charging current passes through it, which is used to heat the sodium battery pack 1.

[0046] Specifically, in actual use, the charging current of the sodium battery pack 1 by the automobile generator 2 must be limited by the constant current source module 4. The current size of the constant current source charging is determined by the parameters of the third resistor R3, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the third diode D3, and the second triode Q3. When the temperature drops below 0°C, the temperature control switch is closed, R3 adds a forward bias to the field effect tube Q2, Q2 gradually turns from blocking to conducting, the current gradually increases, the current flowing through R7 increases, the voltage drop on R7 increases, and a forward bias is added to Q3 through the voltage divider of D3, R5, and R6. Q3 turns from blocking to conducting, reducing the bias of R3 to Q2 and reducing the current of Q2. A balance point of the current flowing through R7 can be reached to form a constant current. Q2 will generate heat due to the voltage drop caused by current regulation, and R7 will also generate heat due to current detection.

[0047] By utilizing the above-mentioned effect, the components corresponding to the constant current source module 4 can be mounted on an aluminum-based PCB board and sandwiched between the unit cells of the sodium battery pack 1 to heat the sodium battery pack 1; when the temperature of the sodium battery pack 1 rises above 0°C, the temperature control switch is disconnected, the control end of the normally closed relay is powered off, and the controlled end of the normally closed relay is closed, and the generator 2 can charge the sodium battery pack 1 with full current, thereby improving the charging efficiency of the sodium battery pack 1.

[0048] In one embodiment, the shunt heating unit 401 includes: a fourth resistor R4, a MOS transistor Q2, a seventh resistor R7, and a third diode D3; the gate of the MOS transistor Q2 is electrically connected to the collector of the second triode Q3 through the fourth resistor R4; the drain of the MOS transistor Q2 is electrically connected to the negative electrode of the sodium battery pack 1; the source of the MOS transistor Q2 is electrically connected to the negative electrode of the generator 2 through the seventh resistor R7; the source of the MOS transistor Q2 is also electrically connected to the anode of the third diode D3; the cathode of the third diode D3 is electrically connected to the base of the second triode Q3 through the fifth resistor R5; when the temperature of the sodium battery pack 1 is lower than the temperature threshold, the temperature control module 3 is turned off, and the MOS transistor Q2 and the seventh resistor R7 dissipate heat when the charging current passes through, so as to heat the sodium battery pack 1.

[0049] Specifically, the large current constant current source requires the field effect transistor Q2 and the seventh resistor R7 to be connected in series and then in parallel with each other, such as Figure 3 As shown, due to the unbalanced current in each path when connected in parallel, D3 and D3-1 are installed to use the maximum current as the current sampling benchmark. The parallel branches can be set to n paths, which can be set according to the constant current, heating power and heat dissipation conditions as needed.

[0050] In one embodiment, the constant current source module 4 further includes: a voltage regulator diode D4; an anode of the voltage regulator diode D4 is electrically connected to the negative electrode of the generator 2; and a cathode of the voltage regulator diode D4 is electrically connected to the collector of the second transistor Q3.

[0051] Zener diode D4 can also be used to clamp the voltage, ensuring that the base of Q3 is always in the proper forward bias state during current regulation and control. When the voltage in the circuit is too high, Zener diode D4 can protect Q3 from overvoltage damage by providing a stable path to prevent the voltage from exceeding a certain limit. Another function of Zener diode D4 is to prevent current from flowing in the reverse direction into the base circuit of Q3. Under certain operating conditions, the current may try to flow in the reverse direction, which may affect the normal operation of Q3. The presence of Zener diode D4 ensures that the current can only flow in the intended direction, preventing instability or damage caused by reverse current.

[0052] In one embodiment, it further includes: a filter module; two ends of the filter module are electrically connected to the positive electrode of the generator 2 and the negative electrode of the generator 2 respectively.

[0053] Specifically, the filter module includes a filter capacitor C. The filter module and the generator module are connected in parallel and can absorb the fluctuation of the generator output voltage during the current regulation process of the constant current source.

[0054] In one embodiment, the generator has a voltage regulator and an excitation coil inside.

[0055] The voltage regulator can effectively prevent the power supply voltage from being too high or too low. Excessive voltage may damage the electronic components in the circuit, causing the equipment to overheat or even burn out; the voltage regulator ensures that the output voltage does not exceed the set safety range by adjusting the excitation current. The voltage of the sodium battery pack N (four strings of 16V, eight strings of 32V) is much higher than the rated voltage of the 12V or 24V car generator (about 14.5V, 29V), so there is no need for charging overvoltage protection. The undervoltage of a single string can be below 1.5V, and the undervoltage will not damage the sodium battery. There is no need for undervoltage protection, and the overvoltage protection requirements can be met by adding an active balancing circuit; after the vehicle is started, the vibration sensor G detects the vibration of the vehicle, outputs a low level, turns on Q1, energizes the coil of the normally closed relay J, and disconnects JK. The purpose is that when the car engine is not started below 0℃, the car generator does not generate electricity, and there is no need to power the normally closed relay J, reducing the current loss in the parking state.

[0056] In summary, this application is designed for sodium battery charging in low temperature environments, and uses a constant current source to limit the charging current. When the ambient temperature is below 0°C, the circuit will automatically switch to current limiting mode to avoid the impact and damage of large currents on sodium batteries. This mechanism effectively prevents sodium batteries from overcharging, polarization, and dendrite formation at low temperatures, ensuring the safe charging of sodium batteries in low temperature environments.

[0057] Embodiment 2

[0058] As an improvement of the first embodiment, the second embodiment further provides a method for controlling a low-temperature charging current limiting circuit of a sodium battery pack 1.

[0059] Applied to the sodium battery low temperature charging current limiting circuit in the first embodiment, the method includes:

[0060] Obtaining the temperature of the sodium battery pack 1, and determining whether the temperature of the sodium battery pack 1 is greater than a temperature threshold;

[0061] If yes, the temperature control module 3 is controlled to be turned on, so that the generator 2 directly charges the sodium battery pack 1 through the temperature control module 3;

[0062] If not, the temperature control module 3 is controlled to be turned off so that the generator 2 charges the sodium battery pack 1 through the constant current source module 4, and the heat generated by the constant current source module 4 when working is used to heat the sodium battery pack 1; when the temperature of the sodium battery pack 1 is higher than the temperature threshold, the temperature control module 3 is controlled to be turned on again so that the generator 2 directly charges the sodium battery pack 1 through the temperature control module 3.

[0063] Specifically, by adopting the above control method, the charging mode of the sodium battery pack can be adjusted according to the temperature of the sodium battery pack, and the sodium battery pack can be heated when charging at a low temperature so that the temperature can operate within an appropriate temperature range, thereby improving the service life and safety of the sodium battery pack.

[0064] Embodiment 3

[0065] Further, such as Figure 3 As shown, the present application also provides another circuit schematic diagram of a constant current source, wherein the constant current source includes two shunt heating units 401, and the two shunt heating units 401 are connected in parallel. And those skilled in the art will know that, based on this embodiment, the shunt heating units 401 can be further increased according to the actual current size and expanded to any number.

[0066] Embodiment 4

[0067] Furthermore, this embodiment also provides a sodium battery pack low temperature charging current limiting device, which includes a sodium battery pack and a sodium battery pack low temperature charging current limiting circuit as in Embodiment 1; the sodium battery pack is electrically connected to the sodium battery pack low temperature charging current limiting circuit.

[0068] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.

Claims

1. A sodium battery pack low temperature charging current limiting circuit, characterized in that: include: A generator for charging a sodium battery pack, a temperature control module for switching on or off according to the temperature of the sodium battery pack, and a constant current source module for controlling the charging current of the sodium battery pack and providing heat to the sodium battery pack; One end of the generator is electrically connected to the positive electrode of the sodium battery pack; The other end of the generator is electrically connected to the negative electrode of the sodium battery pack through the temperature control module; The other end of the generator is electrically connected to the negative electrode of the sodium battery pack through the constant current source module; When the temperature of the sodium battery pack is higher than the temperature threshold, the temperature control module is turned on so that the other end of the generator charges the sodium battery pack after passing through the temperature control module; When the temperature of the sodium battery pack is lower than the temperature threshold, the temperature control module is turned off, so that the other end of the generator charges the sodium battery pack through the constant current source module, and the constant current source module is used to dissipate heat to heat the sodium battery pack; The temperature control module includes: a temperature control switch, a vibration sensor, a first transistor and a relay unit; The positive electrode of the generator is electrically connected to the negative electrode of the generator through the temperature control switch and the vibration sensor in sequence; The output end of the vibration sensor is electrically connected to the base of the first transistor; The emitter of the first transistor is electrically connected to the constant current source module; the emitter of the first transistor is also electrically connected to the positive electrode of the generator through the temperature control switch; The collector of the first triode is electrically connected to the negative electrode of the generator through the control end of the relay unit; The negative electrode of the generator is also electrically connected to the negative electrode of the sodium battery pack through the controlled end of the relay unit.

2. A sodium battery pack low temperature charging current limiting circuit according to claim 1, characterized in that: The temperature control module further includes: a first resistor, a second resistor and a first diode; The base of the first transistor is electrically connected to the emitter of the first transistor through a first resistor; The base of the first transistor is electrically connected to the output end of the vibration sensor through a second resistor; The cathode of the first diode is electrically connected to the collector of the first triode; The anode of the first diode is electrically connected to the negative electrode of the generator.

3. A sodium battery pack low temperature charging current limiting circuit according to claim 2, characterized in that: The constant current source module comprises: a second triode, a third resistor, a fifth resistor, a sixth resistor and at least one shunt heating unit; The collector of the second transistor is electrically connected to the emitter of the first transistor through the third resistor; The collector of the second triode is also electrically connected to the control end of the shunt heating unit; The base of the second transistor is electrically connected to the current detection end of the shunt heating unit through the fifth resistor; the base of the second transistor is electrically connected to the negative electrode of the generator through the sixth resistor; The emitter of the second triode is electrically connected to the negative electrode of the generator; The input end of the shunt heating unit is electrically connected to the negative electrode of the sodium battery pack; the output end of the shunt heating unit is electrically connected to the negative electrode of the generator; When the temperature of the sodium battery pack is lower than a temperature threshold, the temperature control module is turned off, and the shunt heating unit dissipates heat when a charging current passes therethrough to heat the sodium battery pack.

4. A sodium battery pack low temperature charging current limiting circuit according to claim 3, characterized in that: The shunt heating unit includes: a fourth resistor, a MOS tube, a seventh resistor, and a third diode; The gate of the MOS tube is electrically connected to the collector of the second transistor through the fourth resistor; The drain of the MOS tube is electrically connected to the negative electrode of the sodium battery pack; The source electrode of the MOS tube is electrically connected to the negative electrode of the generator through the seventh resistor; The source of the MOS tube is also electrically connected to the anode of the third diode; the cathode of the third diode is electrically connected to the base of the second transistor through the fifth resistor; When the temperature of the sodium battery pack is lower than a temperature threshold, the temperature control module is turned off, and the MOS tube and the seventh resistor dissipate heat when a charging current passes through them, so as to heat the sodium battery pack.

5. A sodium battery pack low temperature charging current limiting circuit according to claim 4, characterized in that: The constant current source module further includes: a voltage stabilizing diode; an anode of the voltage stabilizing diode is electrically connected to a negative electrode of the generator; and a cathode of the voltage stabilizing diode is electrically connected to a collector of the second transistor.

6. A sodium battery pack low temperature charging current limiting circuit according to claim 1, characterized in that: Also includes: Filter module; Two ends of the filter module are electrically connected to the positive pole of the generator and the negative pole of the generator respectively.

7. A sodium battery pack low temperature charging current limiting circuit according to claim 1, characterized in that: There are voltage regulator and excitation coil inside the generator.

8. A method for controlling a sodium battery pack low temperature charging current limiting circuit, characterized in that: Applied to the sodium battery low temperature charging current limiting circuit as claimed in any one of claims 1 to 7, the method comprising: Acquiring the temperature of the sodium battery pack, and determining whether the temperature of the sodium battery pack is greater than a temperature threshold; If yes, controlling the temperature control module to be turned on so that the generator can directly charge the sodium battery pack through the temperature control module; If not, the temperature control module is controlled to be turned off so that the generator charges the sodium battery pack through the constant current source module, and the heat generated by the constant current source module when working is used to heat the sodium battery pack; when the temperature of the sodium battery pack is higher than the temperature threshold, the temperature control module is controlled to be turned on again so that the generator directly charges the sodium battery pack through the temperature control module.

9. A sodium battery pack low temperature charging current limiting device, characterized in that: The sodium battery pack low temperature charging current limiting device comprises a sodium battery pack and a sodium battery pack low temperature charging current limiting circuit as claimed in any one of claims 1 to 7; the sodium battery pack is electrically connected to the sodium battery pack low temperature charging current limiting circuit.

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