Emergency lithium battery management control method and lithium battery emergency circuit

Abstract

The application discloses an emergency lithium battery management control method and an emergency lithium battery circuit. The method is suitable for an emergency power supply system comprising at least one lithium battery pack. The method comprises: performing cyclic charging and discharging treatment on each lithium battery pack, wherein the cyclic charging and discharging treatment comprises a trickle charging and discharging stage and a constant voltage stage which are cyclically performed within a set time; in the trickle charging and discharging stage, the lithium battery pack is controlled to be discharged at a first preset current for a first preset time, then the lithium battery pack is controlled to be charged at a second preset current for a second preset time, and then the constant voltage stage is performed; and in the constant voltage stage, the charging voltage of the lithium battery pack is set to a first preset voltage value and maintained for a third preset time. The application can prolong the service life of the lithium battery pack, reduce the failure risk, effectively improve the reliability of the backup power supply system, and play a positive role in maintaining the stable operation of a nuclear power plant.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of backup power supply, in particular to an emergency lithium battery management control method and lithium battery emergency circuit. BACKGROUND

[0002] The backup power supply system is one of the important working power sources for protection, control and communication loads in nuclear power plants, transformer substations, communication base stations and other power engineering. When the AC power supply or charger fails, the battery pack in the backup power supply system needs to be used to provide uninterrupted power supply for important DC loads.

[0003] At present, the backup power supply system in the nuclear power plant uses valve-regulated lead-acid batteries, which are suitable for long-term float charging operation, but they have the disadvantages of short service life, difficult to find internal open circuit, low energy density, high environmental requirements, and large maintenance workload.

[0004] Lithium batteries have the advantages of long service life, high energy density, easy online monitoring, safety and no pollution. Although some schemes propose to directly replace lead-acid batteries with lithium batteries, long-term float charging of lithium batteries will cause a side reaction between the internal electrolyte and the negative electrode, resulting in increased internal resistance and accelerated life decay. And with the increase of the float charging voltage, the side reaction will be exponentially intensified.

[0005] In the prior art, to solve the problem that lithium batteries cannot be used for long-term float charging, some schemes propose to actively cut off the lithium battery pack after it is fully charged and turn it into a hot standby state. When discharging is needed, the circuit is closed through pressure difference and other signals to supply power to the DC load. However, in the above method, the switching from the hot standby state to the discharging state takes tens of milliseconds, and these control circuits have a fault probability, which is difficult to detect online in time, and cannot meet the reliability and power quality requirements of nuclear power plants for backup power supply systems. SUMMARY

[0006] The technical problem to be solved by the present application is to provide an emergency lithium battery management control method and lithium battery emergency circuit for at least one defect in the prior art.

[0007] The technical solution adopted by the present application to solve the technical problem is: constructing an emergency lithium battery management control method applicable to an emergency power supply system including at least one lithium battery pack, comprising:

[0008] S1, performing a cyclic charging and discharging process on each lithium battery pack, wherein the cyclic charging and discharging process includes a trickle charging and discharging phase and a constant voltage phase cyclically executed within a set time:

[0009] In the trickle charge and discharge phase, the lithium battery group is controlled to be discharged at a first preset current for a first preset time, then controlled to be charged at a second preset current for a second preset time, and then the constant voltage phase is executed.

[0010] In the constant voltage phase, the charging voltage of the lithium battery group is set to a first preset voltage value and maintained for a third preset time.

[0011] Preferably, in the S1, the cyclic charge and discharge process further comprises a standing phase executed after the constant voltage phase;

[0012] In the standing phase, the lithium battery group is controlled not to be discharged and charged for a fourth preset time, and then the trickle charge and discharge phase is executed.

[0013] Preferably, in the S1, further comprising:

[0014] In the process of discharging each lithium battery group, the current input current of the charging device is controlled according to the first preset current and the current load current of the common output terminal of the lithium battery group; in the process of charging each lithium battery group, the current input current of the charging device is controlled according to the second preset current and the current load current of the common output terminal of the lithium battery group.

[0015] Preferably, the emergency lithium battery management control method further comprises:

[0016] S2, performing daily capacity checking processing on each lithium battery group.

[0017] Preferably, in the S2, the daily capacity checking processing comprises:

[0018] Discharge each lithium battery group according to a preset period, and during the process of discharging a single lithium battery group, the lithium battery group not discharging is temporarily used as an emergency power supply.

[0019] Preferably, further comprising:

[0020] S3, setting a protection output loop at the common output terminal of the lithium battery group, and controlling the voltage of the protection output loop according to a hierarchical control process.

[0021] Preferably, in the S3, the hierarchical control process comprises:

[0022] A number of diodes are used to form a voltage reduction chain, and a bypass loop is set at both ends of each diode, whether the bypass loop is turned on or not is controlled according to the output voltage of the emergency power supply system, so as to control the voltage reduction value of the voltage reduction chain, and then the voltage of the protection output loop is hierarchically reduced according to a preset protection voltage.

[0023] Preferably, the emergency lithium battery management control method further comprises:

[0024] S4, acquiring and displaying performance parameters of each lithium battery pack; wherein the performance parameters include at least one of output voltage, output current, real-time temperature and current state of charge.

[0025] The application also constructs a lithium battery emergency circuit, characterized in that it comprises:

[0026] at least one lithium battery pack;

[0027] a charge-discharge circuit connected with each lithium battery pack, used for controlling each lithium battery pack to perform a cycle charge-discharge process according to a cycle charge-discharge instruction; wherein the cycle charge-discharge process comprises a trickle charge-discharge phase and a constant voltage phase which are cyclically executed within a set time: in the trickle charge-discharge phase, the lithium battery pack is controlled to be discharged at a first preset current for a first preset time, then the lithium battery pack is controlled to be charged at a second preset current for a second preset time, and then the constant voltage phase is executed; in the constant voltage phase, the charging voltage of the lithium battery pack is set to a first preset voltage value and maintained for a third preset time;

[0028] a master control unit connected with the charge-discharge circuit, used for outputting the cycle charge-discharge instruction.

[0029] Preferably, the lithium battery emergency circuit further comprises:

[0030] a nuclear capacity unit connected with each lithium battery pack, used for controlling the lithium battery pack to perform a daily nuclear capacity process according to a nuclear capacity instruction output by the master control unit.

[0031] Preferably, each lithium battery pack comprises a battery unit, a first bypass switch and a discharge switch;

[0032] the battery unit is connected with the second end of the first bypass switch and the second end of the discharge switch, the first end of the first bypass switch is connected with the nuclear capacity unit, and the first end of the discharge switch is connected with the charge circuit; when the lithium battery pack performs the nuclear capacity discharge, the nuclear capacity instruction makes the first bypass switch conductive and the discharge switch non-conductive; when the lithium battery pack does not perform the nuclear capacity discharge, the nuclear capacity instruction makes the discharge switch conductive and the first bypass switch non-conductive.

[0033] Preferably, the lithium battery emergency circuit further comprises:

[0034] a hierarchical control circuit, one end of which is connected with a common output end of each lithium battery pack, the other end of which is an output end of a protection output loop, and the hierarchical control circuit is used for controlling the output voltage of the protection output loop according to a hierarchical control instruction output by the master control unit.

[0035] Preferably, the hierarchical control circuit comprises several voltage reduction units; each of the voltage reduction units is connected in series in turn;

[0036] Each of the voltage reduction units comprises a diode and a second bypass switch; the diode is connected in parallel with the second bypass switch, the anode of the diode is the input end of the voltage reduction unit for connecting the common output end of the lithium battery pack or the output end of the voltage reduction unit located at the front end, and the cathode of the diode is the output end of the voltage reduction unit for connecting the voltage reduction unit located at the rear end or as the output end of the protection output circuit; the master control unit controls whether the second bypass switch is turned on or not, so as to control the voltage reduction value of the hierarchical control circuit, and then grade the voltage reduction of the protection output circuit according to the preset protection voltage.

[0037] The present application has the following beneficial effects: the present application greatly reduces the trickle float charging time of the lithium battery pack through the cyclic charging and discharging process, thereby reducing the loss of the lithium battery pack as much as possible and effectively improving the service life thereof; the capacity change of the lithium battery pack can be monitored by the staff in a short period through the daily capacity checking process, not only facilitating the staff to timely maintain the backup power supply system, but also making the capacity attenuation trend prediction of the lithium battery pack more accurate; the protection output circuit is arranged at the common output end of the lithium battery pack, which effectively reduces the influence of the output voltage fluctuation of the lithium battery pack on the service life of the voltage-sensitive load during the cyclic charging and discharging process. The present application can prolong the service life of the lithium battery pack, reduce the failure risk, effectively improve the reliability of the backup power supply system, and play a positive role in maintaining the stable operation of the nuclear power plant. BRIEF DESCRIPTION OF DRAWINGS

[0038] The present application will be further described below in conjunction with the drawings and embodiments, wherein:

[0039] Figure 1 is an example one flow chart of the emergency lithium battery management control method provided by the present application;

[0040] Figure 2 is an example two flow chart of the emergency lithium battery management control method provided by the present application;

[0041] Figure 3 is a schematic diagram of the lithium battery emergency circuit provided by the present application. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0043] REFERENCE Figure 1The application provides an emergency lithium battery management control method, which is suitable for an emergency power supply system comprising at least one lithium battery pack, and the method comprises the following steps.

[0044] S1, performing a cyclic charging and discharging process on each lithium battery pack, wherein the cyclic charging and discharging process comprises a trickle charging and discharging phase and a constant voltage phase which are cyclically performed within a set time; in the trickle charging and discharging phase, the lithium battery pack is controlled to be discharged at a first preset current for a first preset time, then the lithium battery pack is controlled to be charged at a second preset current for a second preset time, and then the constant voltage phase is performed; in the constant voltage phase, the charging voltage of the lithium battery pack is set to a first preset voltage value and maintained for a third preset time.

[0045] Specifically, to facilitate the shift of staff, the set time can be set to 24 hours; to avoid excessive discharging and charging current to increase the heat generation of the lithium battery pack and affect the service life of the lithium battery pack, the first preset current and the second preset current can be set to a rate not greater than 0.03C for charging and discharging; to avoid the situation that the lithium battery pack has a long endurance time when entering the emergency state in the case that a large amount of electricity is released during discharging, the minimum electricity of the lithium battery pack in the discharging phase needs to be limited, and the first preset time and the second preset time should be set within 11.1 hours; for the constant voltage phase, the first preset voltage value is set to be slightly higher than the current voltage of the lithium battery pack, so that the lithium battery pack is trickle charged in a short time to ensure that the lithium battery is fully charged, and the time of each cycle can be maintained at the set time by adjusting the third preset time. It can be understood that by performing the cyclic charging and discharging process, the lithium battery pack can work in the cycle of "charging-discharging-charging" for a long time, so as to greatly reduce the time of trickle float charging of the lithium battery pack, thereby reducing the loss of the lithium battery pack as much as possible and effectively improving the service life thereof.

[0046] In some embodiments, as Figure 2 In S1, the cyclic charging and discharging process further comprises a static stage performed after the constant voltage stage; in the static stage, the lithium battery pack is controlled not to be discharged and charged for a fourth preset time, and then the trickle charging and discharging phase is performed.

[0047] Specifically, in the static stage, the input voltage of the lithium battery pack is turned off and maintained for the fourth preset time, and the time of trickle charging of the lithium battery pack can be further reduced by adding the static stage, and the adjustment flexibility of the first, second and third preset times is increased; in addition, the lithium battery pack is generally composed of multiple lithium batteries, and the full voltage of each lithium battery has a slight difference, and during the static stage, the voltages of the batteries can be adaptively balanced, which has a positive effect on prolonging the service life of the lithium battery pack, and in addition, if the lithium battery pack enters the discharging phase immediately after the constant voltage phase is performed, the lithium battery pack may also be damaged.

[0048] In some embodiments, in step S1, the setting time can be set to 24 hours, the first preset time and the second preset time can be set to 11.1 hours, the first preset current and the second preset current can be set to 0.03C, the third preset time can be set to 0.5 hours, and the fourth preset time can be set to 1.3 hours.

[0049] Since the charging and discharging current of each lithium battery pack affects the current of the common output end of the lithium battery pack during the cycle charging and discharging process, and further affects the input current of the load, in order to ensure the stability of the input current of the load, in some embodiments, step S1 further includes: during the discharging process of each lithium battery pack, controlling the current input current of the charging device according to the first preset current and the current load current of the common output end of the lithium battery pack; during the charging process of each lithium battery pack, controlling the current input current of the charging device according to the second preset current and the current load current of the common output end of the lithium battery pack. Specifically, during the discharging process of each lithium battery pack, the current input current of the charging device is equal to the current load current of the common output end of the lithium battery pack minus the first preset current; during the charging process of each lithium battery pack, the current input current of the charging device is equal to the current load current of the common output end of the lithium battery pack plus the second preset current.

[0050] In a certain nuclear power plant, in order to verify the capacity effectiveness of the lithium battery pack, the battery is generally discharged once every quarter, every half year or every year, but since the cycle of nuclear capacity discharge is long, sudden accelerated aging of the battery cannot be found in time, therefore, in some embodiments, the emergency lithium battery management control method further includes step S2: performing daily capacity verification on each lithium battery pack.

[0051] Further, in S2, the daily capacity verification process includes: sequentially performing capacity verification discharge on each lithium battery pack according to a preset period, and during the capacity verification discharge of a single lithium battery pack, lithium battery packs not performing capacity verification discharge form a temporary emergency power supply, so as to ensure that the battery capacity can still maintain the original power supply hours, thereby maintaining the normal operation of the backup power supply system, which is conducive to reducing the overhaul period of the nuclear power plant and has significant economic benefits. Further, for a backup power supply system having only one lithium battery pack, a temporary emergency power supply can be used to replace the lithium battery pack during the daily capacity verification process. Specifically, the preset period can be set to be within 1 week, i.e., at least once per week for each lithium battery pack to perform capacity verification discharge, and further, when the lithium battery pack has been used for a long time, the preset period can be set to 1 to 3 days, so as to monitor the capacity of the lithium battery pack at all times, so as to timely maintain the backup power supply system and make the working staff more accurate in predicting the capacity attenuation trend of the lithium battery pack. In addition, since the purpose of the daily capacity verification process is to verify the capacity of the lithium battery pack, the daily capacity verification process should be performed when each lithium battery pack is fully charged, and during the process, the cyclic charging and discharging process can be temporarily suspended to avoid the battery capacity of the temporary emergency power supply being too small. In addition, in order to meet the power supply demand of the backup power supply system, the capacity of the lithium battery pack should meet the requirement that: under the condition that two lithium battery packs are fully charged or three lithium battery packs have only 66.7% of the capacity, the power supply demand of the backup power supply system can still be met.

[0052] Since the lithium battery pack fluctuates within a certain voltage range during the cyclic charging and discharging process, the output voltage of the lithium battery pack also fluctuates, and this voltage fluctuation affects the service life of voltage-sensitive loads. Therefore, in some embodiments, the emergency lithium battery management control method further includes step S3: setting a protection output circuit at the common output end of the lithium battery pack, and controlling the voltage of the protection output circuit according to the hierarchical control process, so as to ensure that the input voltage of the voltage-sensitive load is stable within a certain range, thereby protecting the voltage-sensitive load. The lithium battery packs in a general backup power supply system are connected in parallel for output, and therefore the common output end of the lithium battery pack refers to the positive connection point of each lithium battery pack.

[0053] Further, in S3, the hierarchical control process includes: using several diodes to form a voltage reduction chain, and setting a bypass loop at both ends of each diode, controlling whether the bypass loop is turned on according to the output voltage of the emergency power supply system, to control the voltage reduction value of the voltage reduction chain, and then hierarchically reducing the voltage of the protection output loop according to the preset protection voltage. Specifically, by taking advantage of the characteristics of diodes having a fixed conduction voltage drop to reduce the voltage, the number of conduction diodes can be controlled to achieve the voltage reduction function. For example, if the voltage reduction chain is composed of several silicon diodes with a conduction voltage drop of 1.4V, the bypass loop is a direct current contactor with a conduction voltage drop close to zero, and the voltage of the protection output loop is 1V higher than the preset protection voltage, the bypass loop of one of the silicon diodes can be turned on to reduce the voltage of the protection output loop by 1.4V, so that the voltage does not exceed the preset protection voltage, thereby protecting the voltage-sensitive load.

[0054] In order to monitor the working condition of the lithium battery pack at any time, in some embodiments, the emergency lithium battery management control method further includes step S4: obtaining and displaying the performance parameters of each lithium battery pack; wherein the performance parameters include at least one of output voltage, output current, real-time temperature and current state of charge.

[0055] As shown in Figure 3 The present application also provides a lithium battery emergency circuit, which comprises: a charge-discharge circuit 2, a main control unit 5, and at least one lithium battery pack 1.

[0056] The charge-discharge circuit 2 is connected with each lithium battery pack 1, and is used to control each lithium battery pack 1 to perform a cyclic charge-discharge process according to a cyclic charge-discharge instruction; wherein the cyclic charge-discharge process includes a trickle charge-discharge phase and a constant voltage phase which are cyclically executed within a set time: in the trickle charge-discharge phase, the lithium battery pack is controlled to discharge at a first preset current for a first preset time, then the lithium battery pack is controlled to charge at a second preset current for a second preset time, and then the constant voltage phase is executed; in the constant voltage phase, the charging voltage of the lithium battery pack is set to a first preset voltage value, and maintained for a third preset time.

[0057] In some embodiments, the charge-discharge circuit 2 includes a plurality of charging units 21, which are used to convert alternating current power into direct current power to supply power to loads requiring direct current power (referred to as direct current loads) and lithium battery packs, and the output power is determined according to the charge-discharge current of the direct current loads and the lithium battery packs; and the number of charging units 21 is greater than the number of lithium battery packs 1, so as to form a redundant power supply mode, which effectively avoids affecting the operation of the entire lithium battery emergency circuit due to the failure of individual charging units 21.

[0058] The main control unit 5 is connected with the charge-discharge circuit 2, and is used to output a cyclic charge-discharge instruction. In the drawings, the necessary cables for connecting the main control unit 5 with other components or devices are not shown.Figure 3 It is displayed in the middle.

[0059] Furthermore, the main control unit 5 can also control the resting phase executed by each lithium battery pack 1 after the constant voltage phase ends; wherein, during the resting phase, the lithium battery pack is controlled not to discharge or charge within a fourth preset time, and then the trickle charge and discharge phase is executed.

[0060] Furthermore, during the discharge process of each lithium battery pack, the main control unit 5 calculates the current input current of the charging and discharging circuit 2 based on the first preset current and the current load current of the common output terminal 200 of the lithium battery pack; during the charging process of each lithium battery pack, the main control unit 5 controls the current input current of the charging and discharging circuit 2 based on the second preset current and the current load current of the common output terminal 200 of the lithium battery pack.

[0061] In some embodiments, such as Figure 3 As shown, the lithium battery emergency circuit also includes a current transformer 6; the current transformer 6 is located at the common output terminal 200 of the lithium battery pack and is used to collect the current load current of the common output terminal 200 of the lithium battery pack. The current transformer 6 can be a Hall effect current transformer.

[0062] In some embodiments, such as Figure 3 As shown, the lithium battery emergency circuit also includes a core capacity unit 3.

[0063] The capacity unit 3 is connected to each lithium battery pack 1 and is used to control the lithium battery pack 1 to perform daily capacity processing according to the capacity instructions output by the main control unit 5.

[0064] Furthermore, such as Figure 3 As shown, each lithium battery pack 1 includes a battery cell 11, a first bypass switch 12, and a discharge switch 13.

[0065] Battery unit 11 is connected to the second terminal of the first bypass switch 12 and the second terminal of the discharge switch 13. The first terminal of the first bypass switch 12 is connected to the capacity-matching unit, and the first terminal of the discharge switch 13 is connected to the charging circuit. When the lithium battery pack 1 is undergoing capacity-matching discharge, the capacity-matching command turns on the first bypass switch 12 and turns off the discharge switch 13, that is, the battery unit 11 is connected to the capacity-matching unit, thereby performing capacity-matching processing. When the lithium battery pack 1 is not undergoing capacity-matching discharge, the discharge switch 13 is turned on and the first bypass switch 12 is turned off according to the capacity-matching command, that is, the battery unit 11 is connected to the common output terminal of the lithium battery pack 1, so as to serve as a temporary emergency power source to meet the power supply requirements of the backup power system.

[0066] In some embodiments, such as Figure 3 As shown, the lithium battery emergency circuit also includes a graded control circuit 4.

[0067] a hierarchical control circuit 4, one end of which is connected to the common output end of each lithium battery pack 1, and the other end of which is an output end of the protection output circuit, and the hierarchical control circuit 4 controls the output voltage of the protection output circuit according to a hierarchical control instruction output by the master control unit 5.

[0068] Further, as shown in Figure 3 the hierarchical control circuit 4 includes a plurality of voltage reduction units; each voltage reduction unit is connected in series; each voltage reduction unit includes a diode and a second bypass switch (not shown); the diode is connected in parallel with the second bypass switch, the anode of the diode is the input end of the voltage reduction unit for connecting the common output end of the lithium battery pack 1 or the output end 400 of the voltage reduction unit located at the front end, and the cathode of the diode is the output end 400 of the voltage reduction unit for connecting the voltage reduction unit located at the rear end or as the output end of the protection output circuit; the master control unit 5 controls the voltage reduction value of the hierarchical control circuit 4 by controlling whether the second bypass switch is turned on or not, so as to reduce the voltage of the protection output circuit according to the preset protection voltage. Wherein, the front end and the rear end of the voltage reduction unit are defined according to the current flow direction: assuming that the voltage reduction unit connected to the common output end of each lithium battery pack 1 is the voltage reduction unit located at the front end, the voltage reduction unit located at the rear end of the voltage reduction unit located at the front end refers to the voltage reduction unit directly connected to it, and correspondingly, the voltage reduction unit located at the front end of the voltage reduction unit located at the rear end refers to the voltage reduction unit located at the front end.

[0069] In some embodiments, as shown in Figure 3 the lithium battery emergency circuit further includes an output DC contactor 7 and a plurality of power supply circuits 8. Specifically, for the DC contactor 7, one end of the output DC contactor 7 is connected to the common output end 200 of the lithium battery pack, and the other end of the output DC contactor 7 is connected to the hierarchical control circuit 4 as a DC bus output end 300, which can be connected to a DC load. The DC contactor 7 is used to actively disconnect the connection with the DC load when the master control unit 5 determines that the load carrying condition is not met or fire alarm, lithium over-discharge and other situations occur. For the power supply circuit 8, one part of the input end of the power supply circuit 8 is connected to the DC bus output end 300, and the other part of the input end of the power supply circuit 8 is connected to the output end of the hierarchical control circuit 4. The output end of each power supply circuit 8 is used to connect to a DC load, and each power supply circuit 8 further controls whether to supply power to the corresponding DC load according to the opening and closing instruction of the master control unit 5.

[0070] In some embodiments, the lithium battery emergency circuit further includes a human-computer interaction unit, which is used to display performance parameters of each lithium battery pack; wherein the performance parameters include at least one of output voltage, output current, real-time temperature and current power state.

[0071] Correspondingly, each lithium battery pack further comprises a heat dissipation member and a battery management unit (not shown) for acquiring performance parameters of the battery pack, a human-computer interaction unit, and the battery management unit and the human-computer interaction unit are connected to the master control unit 5, so that the master control unit can detect the working state of the lithium battery in real time, which includes whether the battery is faulty, whether the battery is over-discharged, the battery capacity, etc.

[0072] To improve the reliability of the alternating current power supply, in some embodiments, as shown in Figure 3 The lithium battery emergency circuit further comprises a dual power supply switching switch 9, the input end of the dual power supply switching switch 9 is connected to two alternating current power supplies, the output end of the dual power supply switching switch 9 is connected to the input end of the charge-discharge circuit 2, the output end of the dual power supply switching switch 9 also serves as an alternating current bus output end 100 for connecting loads requiring alternating current power supply, and the dual power supply switching switch 9 can automatically switch to another alternating current power supply when detecting that one alternating current power supply is lost, thereby ensuring the stability of the alternating current power supply input.

[0073] Further, necessary copper busbars and copper core cables are used to connect the units.

[0074] It can be understood that, without the need to control the cut-off of the lithium battery pack after full charging, the lithium battery pack is subjected to cyclic charge-discharge processing, so that the lithium battery pack works in the cycle of “charging-discharging-charging” for a long time, thereby greatly reducing the trickle float time of the lithium battery pack, and thus reducing the loss of the lithium battery pack as much as possible and effectively improving the service life thereof; the capacity of the lithium battery pack is subjected to daily capacity checking processing, so that the working personnel can monitor the capacity change of the lithium battery pack in a short period, which not only facilitates the working personnel to timely maintain the backup power supply system, but also makes the prediction of the capacity attenuation trend of the lithium battery pack more accurate; the protection output loop is arranged at the common output end of the lithium battery pack, which effectively reduces the influence of the fluctuation of the output voltage of the lithium battery pack on the service life of the voltage-sensitive load during the cyclic charge-discharge processing. Further, the lithium battery is used to replace the lead-acid storage battery as the energy storage element of the backup power supply system, has the advantages of long service life, many charge-discharge cycles, small volume ratio, low requirement for environmental temperature ventilation, simple maintenance work, no heavy metal pollution, etc., can prolong the service life of the lithium battery pack, reduce the risk of failure, effectively improve the reliability of the backup power supply system, and play a positive role in maintaining the stable operation of the nuclear power plant.

[0075] It can be understood that the above embodiments only express the preferred embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application; it should be pointed out that for ordinary skilled in the art, the above technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which belong to the protection scope of the present application; therefore, any equivalent transformation and modification made with the patent claim scope of the present application shall belong to the coverage of the patent claim of the present application.

Claims

1. An emergency lithium battery management control method, applicable to an emergency power supply system comprising at least one lithium battery pack, characterized in that, Comprising: S1, performing cyclic charging and discharging treatment on each of the lithium battery packs, wherein the cyclic charging and discharging treatment comprises a trickle charging and discharging phase, a constant voltage phase and a standing phase performed after the constant voltage phase, which are cyclically performed within a set time: In the trickle charging and discharging phase, the lithium battery pack is controlled to be discharged at a first preset current for a first preset time, then controlled to be charged at a second preset current for a second preset time, and then the constant voltage phase is performed; the first preset current is equal to the second preset current and not greater than 0.03C, and the first preset time is equal to the second preset time; In the constant voltage phase, the charging voltage of the lithium battery pack is set to a first preset voltage value and maintained for a third preset time; In the standing phase, the lithium battery pack is controlled not to be discharged and charged within a fourth preset time, and then the trickle charging and discharging phase is performed; The set time is 24 hours; In the S1, further comprising: During discharging of each of the lithium battery packs, the current input current of a charging device is controlled according to the first preset current and the current load current of the common output terminal of the lithium battery packs; during charging of each of the lithium battery packs, the current input current of the charging device is controlled according to the second preset current and the current load current of the common output terminal of the lithium battery packs; wherein the common output terminals of the lithium battery packs are connected to each other.

2. The emergency lithium battery management control method of claim 1, wherein, Further comprising: S2, performing daily capacity checking treatment on each of the lithium battery packs.

3. The emergency lithium battery management control method of claim 2, wherein, In the S2, the daily capacity checking treatment comprises: According to a preset period, sequentially performing capacity checking discharging on each of the lithium battery packs, and during capacity checking discharging of a single lithium battery pack, the lithium battery packs not performing the capacity checking discharging form a temporary emergency power supply.

4. The emergency lithium battery management control method of claim 1, wherein, Further comprising: S3, setting a protection output loop at the common output terminal of the lithium battery packs, and controlling the voltage of the protection output loop according to a hierarchical control treatment.

5. The emergency lithium battery management control method of claim 4, wherein, In the S3, the hierarchical control treatment comprises: Using a plurality of diodes to form a voltage reduction chain, and setting a bypass loop at both ends of each diode, and controlling whether the bypass loop is turned on according to the output voltage of the emergency power supply system, so as to control the voltage reduction value of the voltage reduction chain, and then hierarchically reducing the voltage of the protection output loop according to a preset protection voltage.

6. The emergency lithium battery management control method of claim 1, wherein, Further comprising: S4, acquiring and displaying performance parameters of each of the lithium battery packs; wherein the performance parameters comprise at least one of output voltage, output current, real-time temperature and current state of charge.

7. A lithium battery emergency circuit, characterized by Comprising: At least one lithium battery pack (1); The charge-discharge circuit (2) is connected with each lithium battery pack (1) and is used for controlling each lithium battery pack (1) to perform a cycle charge-discharge process according to a cycle charge-discharge instruction; wherein the cycle charge-discharge process comprises a trickle charge-discharge phase, a constant voltage phase and a standing phase which are performed in a set time; in the trickle charge-discharge phase, the lithium battery pack is controlled to be discharged at a first preset current for a first preset time, then the lithium battery pack is controlled to be charged at a second preset current for a second preset time, and then the constant voltage phase is performed; in the constant voltage phase, the charging voltage of the lithium battery pack is set to a first preset voltage value and is maintained for a third preset time; the first preset current is equal to the second preset current and is not greater than 0.03C, the first preset time is equal to the second preset time, and the set time is 24 hours; The main control unit (5) is connected with the charge-discharge circuit (2) and is used for outputting the cycle charge-discharge instruction; The cycle charge-discharge process comprises that in the discharging process of each lithium battery pack, the current input current of a charging device is controlled according to the first preset current and the current load current of the common output end of the lithium battery pack; and in the charging process of each lithium battery pack, the current input current of the charging device is controlled according to the second preset current and the current load current of the common output end of the lithium battery pack; wherein the common output ends of the lithium battery packs are connected with each other.

8. The lithium battery emergency circuit of claim 7, wherein, Further comprising: The nuclear capacity unit (3) is connected with each lithium battery pack (1) and is used for controlling the lithium battery pack (1) to perform a daily nuclear capacity process according to a nuclear capacity instruction output by the main control unit (5).

9. The lithium battery emergency circuit of claim 8, wherein, Each lithium battery pack (1) comprises a battery unit (11), a first bypass switch (12) and a discharge switch (13); The battery unit (11) is connected with the second end of the first bypass switch (12) and the second end of the discharge switch (13), the first end of the first bypass switch (12) is connected with the nuclear capacity unit, and the first end of the discharge switch (13) is connected with the charging circuit; when the lithium battery pack (1) performs nuclear capacity discharge, the nuclear capacity instruction makes the first bypass switch (12) conductive and the discharge switch (13) non-conductive; When the lithium battery pack (1) does not perform the nuclear capacity discharge, the nuclear capacity instruction makes the discharge switch (13) conductive and the first bypass switch (12) non-conductive.

10. The lithium battery emergency circuit of claim 7, wherein, Further comprising: The hierarchical control circuit (4) has one end connected with the common output end (200) of each lithium battery pack and the other end as an output end of a protection output loop, and controls the output voltage of the protection output loop according to a hierarchical control instruction output by the main control unit (5).

11. The lithium battery emergency circuit of claim 10, wherein, The hierarchical control circuit (4) comprises a plurality of step-down units; and each step-down unit is connected in series. The voltage reduction unit comprises a diode and a second bypass switch; the diode is connected in parallel with the second bypass switch, the anode of the diode is the input end of the voltage reduction unit for connecting the common output end (200) of the lithium battery pack or the output end of the voltage reduction unit at the front end, and the cathode of the diode is the output end of the voltage reduction unit for connecting the voltage reduction unit at the rear end or as the output end of the protection output circuit; the main control unit (5) controls the voltage reduction value of the hierarchical control circuit (4) by controlling whether the second bypass switch is turned on or not, thereby grading the voltage reduction of the protection output circuit according to the preset protection voltage.

Images