Iron-lithium battery control method and device based on adjustable resistor and base station power supply system

Abstract

The present invention provides a control method and device for an iron-lithium battery based on an adjustable resistor, and a base station power supply system. The method includes measuring the cell voltage of each lithium battery cell when the iron-lithium battery is in a standby state, selecting a lithium battery cell with a slower discharge speed by a preset voltage value, and processing the lithium battery cells with a slower discharge speed in sequence and in a cycle until the cell voltages of all lithium batteries reach the preset voltage value. The present invention solves the problem that when the iron-lithium battery is used as a backup power source and is in a standby state, each battery cell stops discharging at a different time, resulting in a decrease in the performance of the entire iron-lithium battery and a significant shortening of its lifespan; and that individual batteries charge faster, resulting in a decrease in the performance of the entire iron-lithium battery and a significant shortening of its lifespan.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a lithium iron battery control method and device based on an adjustable resistor, and a base station power supply system. Background Art

[0002] Usually, communication base stations use lithium iron batteries as backup power sources to ensure that the communication base stations can still operate normally in the event of a main power failure or power outage.

[0003] However, the consistency of different batches of lithium iron batteries provided by lithium iron battery manufacturers cannot be guaranteed. During use, especially when the lithium iron battery is in standby mode, the timing of stopping discharge of each battery cell is usually different, and the difference in stopping discharge timing may lead to a series of problems such as capacity loss, life loss, increased internal resistance and safety risks. In the long run, the performance of the entire lithium iron battery will decline and its life will be significantly shortened. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a control method for an iron-lithium battery based on an adjustable resistor, which solves the problem in the prior art that when the iron-lithium battery is used as a backup power source, especially when the iron-lithium battery is in standby mode, the timing of stopping discharge of each battery cell is different, resulting in a decrease in the performance of the entire iron-lithium battery and a significant shortening of its life.

[0005] According to an embodiment of the present invention, a first aspect provides an iron-lithium battery control method based on an adjustable resistor, which is applied to an iron-lithium battery control device, wherein the iron-lithium battery control device includes a lithium battery cell terminal voltage data acquisition module, an iron-lithium battery through current acquisition module, a switch array, an adjustable resistor and a control processor; the iron-lithium battery includes N lithium batteries connected in series; the lithium battery cell terminal voltage data acquisition module acquires the cell voltage of each lithium battery cell, the iron-lithium battery through current acquisition module acquires the through current of the iron-lithium battery, and the switch array includes N+1 array switches, and each lithium battery cell positive electrode ... iron lithium battery cell positive electrode and the iron lithium battery cell positive electrode and the iron lithium battery cell positive electrode and the iron lithium battery cell positive electrode and the iron lithium battery cell positive electrode and the iron lithium battery cell positive electrode and the iron lithium The negative electrodes of the first and second array switches are connected to one end of an array switch, wherein one end of the 2n-1th array switch is connected to the positive electrode of a lithium battery cell, and one end of the 2nth array switch is connected to the negative electrode of the lithium battery cell; the adjustable resistor comprises a first positive switch, a second positive switch, a first negative switch, and a second negative switch, wherein the first positive switch is connected to the other end of the 2n-1th array switch, the second positive switch is connected to the other end of the 2nth array switch, the first negative switch is connected to the other end of the 2n-1th array switch, and the second negative switch is connected to the other end of the 2nth array switch;

[0006] The iron-lithium battery control method based on the adjustable resistor includes:

[0007] SA1. When the lithium iron battery is in standby mode, the cell voltage of each lithium battery cell is measured;

[0008] SA2. If the cell voltage of the nth lithium battery cell is greater than a preset voltage value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium battery cells, the first positive switch, the second positive switch, the first negative switch, the second negative switch and N+1 array switches of the adjustable resistor are adjusted so that the adjustable resistor is connected in series with the nth lithium battery cell, and the resistance value of the adjustable resistor is calculated and set by a first resistance control function; wherein N is a positive integer, and n is a positive integer less than or equal to N;

[0009] SA3, measuring the target voltage of the nth lithium battery cell after the nth lithium battery cell is connected in series with the adjustable resistor set in SA2;

[0010] SA4. If the target voltage is less than or equal to a preset voltage value, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell; if the target voltage is greater than the preset voltage value, the connection relationship between the adjustable resistor and the nth lithium battery cell is maintained;

[0011] SA5. Repeat SA1 to SA4 until the cell voltage of any lithium battery cell is less than or equal to the preset voltage value.

[0012] Optionally, adjusting the first positive switch, the second positive switch, the first negative switch, the second negative switch and N+1 array switches of the adjustable resistor so that the adjustable resistor is connected in series with the nth lithium battery cell includes:

[0013] If the serial number of the nth lithium battery cell is an odd number, the first positive switch and the second negative switch are controlled to be closed, and the resistance value of the adjustable resistor is adjusted to a maximum resistance value;

[0014] After adjusting to the maximum resistance value, the first array switch and the fourth array switch are controlled to be closed, and it is detected whether the first multiple connection line is the positive pole and the second multiple connection line is the negative pole. If so, the first array switch and the fourth array switch are controlled to be opened, and the 2n-1th array switch and the 2nth array switch are controlled to be closed; it is detected again whether the first multiple connection line is the positive pole and the second multiple connection line is the negative pole. If so, the 2n-1th array switch and the 2nth array switch are kept closed, so that the adjustable resistor is connected in series with the nth lithium battery cell;

[0015] If the serial number of the nth lithium battery cell is an even number, the second positive switch and the first negative switch are controlled to be closed, and the resistance value of the adjustable resistor is adjusted to a maximum resistance value;

[0016] After adjusting to the maximum resistance value, the second array switch and the third array switch are controlled to be closed, and it is detected whether the first multiple connection line is the negative pole and the second multiple connection line is the positive pole. If so, the second array switch and the third array switch are controlled to be opened, and the 2nth array switch and the 2n+1th array switch are controlled to be closed; it is detected again whether the first multiple connection line is the negative pole and the second multiple connection line is the positive pole. If so, the 2nth array switch and the 2n+1th array switch are kept closed, so that the adjustable resistor is connected in series with the nth lithium battery cell;

[0017] The connection between the first positive switch, the second positive switch and the array switch of the adjustable resistor is a first complex connection; the connection between the first negative switch, the second negative switch and the array switch of the adjustable resistor is a second complex connection.

[0018] Optionally, when the serial number of the nth lithium battery cell is an odd number, if the condition that the first multiple connection line is the positive pole and the second multiple connection line is the negative pole is not met, a wiring error is reported;

[0019] When the serial number of the nth lithium battery cell is an even number, if the condition that the first multiple connection line is the negative pole and the second multiple connection line is the positive pole is not met, a wiring error is reported.

[0020] Optionally, the first resistance control function is formulated as follows:

[0021] Rt = ROUND(Rn*10);

[0022] Rn=VM / 5;

[0023] Wherein, Rt is the number of switches that open the adjustable resistor. Opening a switch of the adjustable resistor means that the resistance value of the adjustable resistor increases by 0.1 ohms. Rn is the resistance value of the adjustable resistor. VM is the difference between the cell voltage of the nth lithium battery cell and the discharge termination voltage.

[0024] Optionally, the preset voltage value is calculated according to the discharge termination voltage of the iron-lithium battery.

[0025] Optionally, adjusting the positive switch, the negative switch and the array switch of the adjustable resistor to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell includes:

[0026] If the serial number of the nth lithium battery cell is an odd number, turn on the 2n-1th array switch and the 2nth array switch to adjust the resistance value of the adjustable resistor to the maximum;

[0027] After adjusting to the maximum resistance value, detecting whether there is voltage between the first multiple connection line and the second multiple connection line, and if so, turning on the first positive switch and the second negative switch to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell;

[0028] If the serial number of the nth lithium battery cell is an even number, the 2nth array switch and the 2n+1th array switch are turned on to adjust the resistance value of the adjustable resistor to the maximum;

[0029] After adjusting to the maximum resistance value, detecting whether there is voltage between the first multiple connection line and the second multiple connection line, and if so, turning on the second positive switch and the first negative switch to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell;

[0030] The connection between the first positive switch, the second positive switch and the array switch of the adjustable resistor is a first complex connection; the connection between the first negative switch, the second negative switch and the array switch of the adjustable resistor is a second complex connection.

[0031] Optionally, it also includes:

[0032] SB1. When the lithium iron battery is in a charging state, measure the cell voltage of each lithium battery cell, and calculate a first average voltage based on N lithium battery cells, and a difference between the cell voltage of each lithium battery cell and the first average voltage;

[0033] SB2. If the difference between the cell voltage of the nth lithium battery cell and the first average voltage is greater than the first threshold value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium batteries, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted so that the adjustable resistor is connected in parallel with the nth lithium battery cell, and the resistance value of the adjustable resistor is calculated and set using a second resistance control function;

[0034] SB3, measuring the target voltage across the nth lithium battery cell after the nth lithium battery cell is connected in parallel with the adjustable resistor set in SB2, and calculating the second average voltage based on the target voltage and the cell voltages of the remaining lithium batteries measured in SB1, and the difference between the target voltage and the second average voltage;

[0035] SB4. If the difference between the target voltage and the second average voltage is less than a second threshold, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted to terminate the connection between the adjustable resistor and the nth lithium battery cell; if the difference between the target voltage and the second average voltage is greater than or equal to the second threshold, the connection between the adjustable resistor and the nth lithium battery cell is maintained;

[0036] SB5. Repeat steps SB1 to SB4 until the difference between the cell voltage of any lithium battery cell and the first average voltage is less than or equal to the first threshold.

[0037] The second aspect provides a control device based on the standby state of an iron-lithium battery, which is applied to a control processor of the iron-lithium battery control device, wherein the iron-lithium battery control device also includes a lithium battery cell terminal voltage data acquisition module, an iron-lithium battery current acquisition module, a switch array and an adjustable resistor; the control processor executes the iron-lithium battery control method based on an adjustable resistor as described in any one of claims 1 to 7.

[0038] A third aspect provides a base station power supply system, including a base station power supply device and an iron-lithium battery control device;

[0039] The base station power supply device is connected to both ends of the power load, including a communication power supply and an iron-lithium battery, wherein the iron-lithium battery includes N lithium cells connected in series;

[0040] The iron-lithium battery control device and the iron-lithium battery are both connected to the two ends of the communication power supply, the iron-lithium battery serves as a backup power supply for the communication power supply, the communication power supply and the iron-lithium battery both supply power to the communication load, and the communication power supply also supplies power to the iron-lithium battery control device;

[0041] The control processor of the iron-lithium battery control device executes the iron-lithium battery control method based on an adjustable resistor as described in any one of claims 1 to 7.

[0042] The present invention has the following beneficial effects: when the iron-lithium battery is in a standby state, the cell voltage of each lithium battery cell is measured, and the lithium battery cell with a slower discharge speed is selected by a preset voltage value, and the lithium battery cells with a slower discharge speed are processed in turn and cyclically until the cell voltages of all lithium batteries reach the preset voltage value. The processing method is: control the array switch and the switch of the adjustable resistor, so that the adjustable resistor and the nth lithium battery cell are connected in series to form a circuit, so that the nth lithium battery cell can discharge and reduce the voltage based on the adjustable resistor, improve the discharge speed of the nth lithium battery cell, and finally make the lithium battery cell stop discharging timing consistent, avoiding a series of problems such as capacity loss, life loss, increased internal resistance and safety risks that may be caused by the different stop discharge timings of each lithium battery cell. Then, the preset voltage value is used to determine whether the discharge speed of the nth lithium battery cell has been regulated. After determining that the regulation is completed, the array switch and the switch of the adjustable resistor are controlled to separate the adjustable resistor from the iron-lithium battery circuit, that is, the connection relationship between the adjustable resistor and the nth lithium battery cell is terminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a schematic diagram of the implementation process of the lithium iron battery control method based on an adjustable resistor according to an embodiment of the present invention.

[0044] Figure 2 A structural diagram of a lithium iron battery control device according to another embodiment of the present invention;

[0045] Figure 3 A schematic diagram of the implementation flow of a lithium iron battery control method based on an adjustable resistor according to another embodiment of the present invention;

[0046] Figure 4 This is a structural diagram of a base station power supply system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0048] like Figure 1 As shown, the embodiment of the present invention proposes a lithium iron battery control method based on an adjustable resistor, which is applied to Figure 2 In the lithium iron battery control device shown in the figure, Figure 2 The lithium iron battery control device shown is described.

[0049] like Figure 2 As shown, the iron-lithium battery control device includes a lithium battery terminal voltage data acquisition module 21, an iron-lithium battery current acquisition module 22, a switch array 23, an adjustable resistor 24 and a control processor 25; the iron-lithium battery D includes N lithium batteries d connected in series N The connection relationship of the above parts is as follows: The lithium battery terminal voltage data acquisition module 21 collects the voltage of each lithium battery d n The voltage of the iron-lithium battery D is collected by the current collection module 22, and the switch array 23 includes N+1 array switches K N+1 , each lithium battery d N The positive electrode and each lithium battery cell N The negative poles are connected to an array switch K N+1 One end of the array switch K 2n-1 One end is connected to a lithium battery d n The positive pole of the 2nth array switch K 2n One end is connected to a lithium battery d n The adjustable resistor 24 includes a first positive switch KA1, a second positive switch KA2, a first negative switch KA3 and a second negative switch KA4, and also includes a control terminal F electrically connected to the control processor 25. The first positive switch KA1 and the 2n-1th array switch K 2n-1 The other end of the second positive switch KA2 is connected to the 2nth array switch K 2n The other end of the first cathode switch KA3 is connected to the 2n-1th array switch K 2n-1 The other end of the second cathode switch KA4 is connected to the 2nth array switch K 2n The other end of the connection.

[0050] Based on this, Figure 1 As shown, the lithium iron battery control method based on the adjustable resistor includes but is not limited to the following steps:

[0051] SA1. When the lithium iron battery is in standby mode, the cell voltage of each lithium battery cell is measured;

[0052] SA2. If the cell voltage of the nth lithium battery cell is greater than a preset voltage value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium battery cells, the first positive switch, the second positive switch, the first negative switch, the second negative switch and N+1 array switches of the adjustable resistor are adjusted so that the adjustable resistor is connected in series with the nth lithium battery cell, and the resistance value of the adjustable resistor is calculated and set by a first resistance control function; wherein N is a positive integer, and n is a positive integer less than or equal to N;

[0053] SA3, measuring the target voltage of the nth lithium battery cell after the nth lithium battery cell is connected in series with the adjustable resistor set in SA2;

[0054] SA4. If the target voltage is less than or equal to a preset voltage value, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell; if the target voltage is greater than the preset voltage value, the connection relationship between the adjustable resistor and the nth lithium battery cell is maintained;

[0055] SA5. Repeat SA1 to SA4 until the cell voltage of any lithium battery cell is lower than the preset voltage value.

[0056] For the above step SA1, the cell voltage in step SA1 represents the voltage measured when there is no lithium cell in the iron-lithium battery connected in series with the adjustable resistor. Here, the target voltage in step SA3 is compared and explained, and the target voltage represents that there is a lithium cell in the iron-lithium battery connected in series with the adjustable resistor, and it is the voltage measured at both ends of the lithium cell connected in series with the adjustable resistor.

[0057] For the above step SA2, in one embodiment, the preset voltage value is calculated according to the discharge termination voltage of the iron-lithium battery. For example, if the discharge termination voltage is 3.55V, the preset voltage value is 3.65.

[0058] For the above step SA2, the voltage of the nth lithium battery cell is greater than the preset voltage value, indicating that the discharge speed of the nth lithium battery cell is slow. Figure 2The iron-lithium battery control device shown controls an adjustable resistor to form a series circuit with the nth lithium battery cell, so that the nth lithium battery cell can discharge and reduce the voltage based on the adjustable resistor, thereby increasing the discharge speed of the nth lithium battery cell, and finally making the timing of stopping discharge of the lithium batteries tend to be consistent, avoiding a series of problems such as capacity loss, life loss, increased internal resistance and safety risks that may be caused by different timings of stopping discharge of each lithium battery cell.

[0059] In one embodiment, based on Figure 2 The lithium iron battery control device shown in the figure, the implementation of the above step SA2 includes:

[0060] SA211, if the serial number of the nth lithium battery cell is an odd number, control the first positive switch and the second negative switch to be closed, and adjust the resistance value of the adjustable resistor to the maximum resistance value;

[0061] SA212, after adjusting to the maximum resistance value, control the first array switch and the fourth array switch to be closed, detect whether the first multiple connection line is positive and the second multiple connection line is negative, if so, control the first array switch and the fourth array switch to be opened, and control the 2n-1th array switch and the 2nth array switch to be closed; detect again whether the first multiple connection line is positive and the second multiple connection line is negative, if so, keep the 2n-1th array switch and the 2nth array switch closed, so that the adjustable resistor is connected in series with the nth lithium battery cell;

[0062] SA213, if the serial number of the nth lithium battery cell is an even number, control the second positive switch and the first negative switch to be closed, and adjust the resistance value of the adjustable resistor to the maximum resistance value;

[0063] SA214, after adjusting to the maximum resistance value, control the second array switch and the third array switch to be closed, detect whether the first multiple connection line is the negative pole and the second multiple connection line is the positive pole, if so, control the second array switch and the third array switch to be opened, and control the 2nth array switch and the 2n+1th array switch to be closed; detect again whether the first multiple connection line is the negative pole and the second multiple connection line is the positive pole, if so, keep the 2nth array switch and the 2n+1th array switch closed, so that the adjustable resistor is connected in series with the nth lithium battery cell;

[0064] The connection between the first positive switch, the second positive switch and the array switch of the adjustable resistor is a first complex connection; the connection between the first negative switch, the second negative switch and the array switch of the adjustable resistor is a second complex connection.

[0065] It should be noted that in the above steps SA211 to SA214, when the serial number of the nth lithium battery cell is odd, if the condition that the first multiple connection line is the positive pole and the second multiple connection line is the negative pole is not met, a wiring error is reported; when the serial number of the nth lithium battery cell is even, if the condition that the first multiple connection line is the negative pole and the second multiple connection line is the positive pole is not met, a wiring error is reported.

[0066] It should be noted that when the iron-lithium battery is in standby mode, it indicates that the current communication power supply is working normally and the charging process of the iron-lithium battery has ended. Therefore, the iron-lithium battery as a backup power supply is not connected to other loads or the communication power supply. Based on this, through the above steps SA211 to SA214, the adjustable resistor and the nth lithium battery cell can form a series circuit to achieve discharge.

[0067] For the above step SA2, the embodiment of the present invention further describes the provided first resistance control function, wherein the first resistance control function is expressed as follows:

[0068] Rt = ROUND(Rn*10);

[0069] Rn=VM / 5;

[0070] Wherein, Rt is the number of switches that open the adjustable resistor. Opening a switch of the adjustable resistor means that the resistance value of the adjustable resistor increases by 0.1 ohms. Rn is the resistance value of the adjustable resistor. VM is the difference between the cell voltage of the nth lithium battery cell and the discharge termination voltage.

[0071] Among them, the discharge termination voltage is 3.55V.

[0072] For the above step SA4, if the target voltage is less than or equal to the preset voltage value, it means that the embodiment of the present invention has achieved the purpose of accelerating the discharge of the nth lithium battery cell to reach the preset voltage value by connecting the adjustable resistor in series, and the adjustable resistor connected in series in the above step can be removed from the circuit. In one embodiment, step SA4 ends the connection relationship between the adjustable resistor and the nth lithium battery cell in step SA2, that is, ends the regulation process, including:

[0073] SA41. If the serial number of the nth lithium battery cell is an odd number, turn on the 2n-1th array switch and the 2nth array switch to adjust the resistance value of the adjustable resistor to the maximum;

[0074] SA42, after adjusting to the maximum resistance value, detecting whether there is voltage between the first multiple connection line and the second multiple connection line, if so, turning on the first positive switch and the second negative switch to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell;

[0075] SA43. If the serial number of the nth lithium battery cell is an even number, turn on the 2nth array switch and the 2n+1th array switch to adjust the resistance of the adjustable resistor to the maximum;

[0076] SA44, after adjusting to the maximum resistance value, detecting whether there is voltage between the first multiple connection line and the second multiple connection line, if so, turning on the second positive switch and the first negative switch to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell;

[0077] The connection between the first positive switch, the second positive switch and the array switch of the adjustable resistor is a first complex connection; the connection between the first negative switch, the second negative switch and the array switch of the adjustable resistor is a second complex connection.

[0078] Regarding the above step SA5, it can be understood that when there is no lithium battery cell whose voltage is greater than the preset voltage value, it means that the timing of stopping charging of the current lithium battery cell voltage is relatively consistent, thus achieving the control purpose of consistency convergence during the standby process.

[0079] like Figure 3 As shown, in one embodiment, based on Figure 2 The iron-lithium battery control device shown in the figure provides another iron-lithium battery control method based on an adjustable resistor when the iron-lithium battery is in various states, especially in the standby state and the charging state. Figure 1 The steps SA1 to SA5 of the iron-lithium battery control method based on the adjustable resistor shown in the figure further include the following steps:

[0080] SB1. When the lithium iron battery is in a charging state, measure the cell voltage of each lithium battery cell, and calculate a first average voltage based on N lithium battery cells, and a difference between the cell voltage of each lithium battery cell and the first average voltage;

[0081] SB2. If the difference between the cell voltage of the nth lithium battery cell and the first average voltage is greater than the first threshold value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium batteries, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted so that the adjustable resistor is connected in parallel with the nth lithium battery cell, and the resistance value of the adjustable resistor is calculated and set using a second resistance control function;

[0082] SB3, measuring the target voltage across the nth lithium battery cell after the nth lithium battery cell is connected in parallel with the adjustable resistor set in SB2, and calculating the second average voltage based on the target voltage and the cell voltages of the remaining lithium batteries measured in SB1, and the difference between the target voltage and the second average voltage;

[0083] SB4. If the difference between the target voltage and the second average voltage is less than a second threshold, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted to terminate the connection between the adjustable resistor and the nth lithium battery cell; if the difference between the target voltage and the second average voltage is greater than or equal to the second threshold, the connection between the adjustable resistor and the nth lithium battery cell is maintained;

[0084] SB5. Repeat steps SB1 to SB4 until the difference between the cell voltage of any lithium battery cell and the first average voltage is less than or equal to the first threshold.

[0085] For the above step SB1, the first average voltage always represents the voltage average value calculated by the iron-lithium control circuit when the adjustable resistor is not connected to each lithium battery cell. The second average voltage used in step SB3 is associated here for comparative explanation, wherein the second average voltage in step SB3 always represents the target voltage obtained after a certain lithium battery cell is connected in parallel with the adjustable resistor, and the voltage average value calculated by the cell voltage of the remaining lithium batteries, and the cell voltage of the remaining lithium batteries is the cell voltage of the N-1 lithium batteries detected in step SB1 except the nth lithium battery cell. Exemplarily, when the adjustable resistor is not connected, the cell voltage of the first lithium battery cell is b1, the cell voltage of the second lithium battery cell is b2, the cell voltage of the third lithium battery cell is b3, and the cell voltage of the fourth lithium battery cell is b4, then the first average voltage is (b1+b2+b3+b4) / 4. Assuming that in step SB2, the adjustable resistor is connected in parallel with the second lithium battery cell, and assuming that the target voltage measured after the adjustable resistor is connected in parallel with the second lithium battery cell in SB3 is b2', the second average voltage in SB3 is (b1+b2'+b3+b4) / 4.

[0086] For the above step SB2, the difference between the cell voltage of the nth lithium battery cell and the first average voltage is greater than the first threshold value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium batteries, indicating that the cell voltage of the nth lithium battery cell increases faster than the cell voltages of other batteries. The embodiment of the present invention is based on the following example. Figure 2 The iron-lithium battery control device shown controls an adjustable resistor to be connected in parallel with the nth lithium battery cell, and reduces the cell voltage growth rate of the nth lithium battery cell by current shunting, so that the cell voltages converge to a consistent level during the charging process, thereby avoiding the problem that the performance of the entire iron-lithium battery is reduced and the life of the battery is significantly shortened due to the fast charging speed of individual cells.

[0087] In a preferred implementation, the first threshold is 0.1.

[0088] It should be noted that the embodiment of the present invention processes individual battery cells with faster charging speeds, thereby processing lithium battery cells that meet the conditions specified in the above-mentioned step SB2, wherein the conditions specified in step SB2 are that the difference between the battery voltage of the nth lithium battery cell and the first average voltage is greater than the first threshold, and the battery voltage of the nth lithium battery cell is higher than the battery voltages of the remaining lithium battery cells. At this time, for the lithium battery cells that meet the requirements, the difference minus the first average voltage must be greater than 0.

[0089] Regarding the implementation of connecting the adjustable resistor in parallel with the nth lithium battery cell in the above step SB2, it is the same as the above steps SA211 to SA214, which will not be repeated here.

[0090] For the above step SB2, the embodiment of the present invention describes the provided resistance control function, wherein the resistance value of the adjustable resistor is calculated using the second resistance control function, including:

[0091] SB221, obtaining the current flowing through the lithium iron battery collected by the current collection module before the adjustable resistor is connected in parallel;

[0092] SB222. Based on the current flowing through the lithium iron battery before the adjustable resistor is connected in parallel, predict the current flowing through the adjustable resistor after the adjustable resistor is connected in parallel;

[0093] SB223. Substitute the difference between the cell voltage of the nth lithium battery cell and the second average voltage, and the current passing through the adjustable resistor after the adjustable resistor is connected in parallel, into the resistance control function to calculate the resistance value of the adjustable resistor.

[0094] In the embodiment of the present invention, the nth lithium battery cell is shunted by a parallel adjustable resistor. Therefore, the above step SB222 is actually to select the current size to be shunted by the adjustable resistor based on the current passing through the lithium iron battery before the parallel adjustable resistor is connected. Based on this, the detailed implementation method of the above step SB222 includes:

[0095] When the current passing through the lithium iron battery before the parallel adjustable resistor is greater than or equal to X, the current passing through the adjustable resistor after the parallel adjustable resistor is the difference between X+a and the current passing through the lithium iron battery before the parallel adjustable resistor;

[0096] When the current passing through the lithium iron battery before the parallel adjustable resistor is greater than or equal to Xa, and less than X, the current passing through the adjustable resistor after the parallel adjustable resistor is the difference between X and the current passing through the lithium iron battery before the parallel adjustable resistor;

[0097] When the current passing through the lithium iron battery before the parallel adjustable resistor is greater than or equal to X-2a, and less than Xa, the current passing through the adjustable resistor after the parallel adjustable resistor is the difference between Xa and the current passing through the lithium iron battery before the parallel adjustable resistor;

[0098] When the passing current of the iron-lithium battery before the parallel adjustable resistor is less than X-2a, the passing current of the adjustable resistor after the parallel adjustable resistor is the difference between X-2a and the passing current of the iron-lithium battery before the parallel adjustable resistor.

[0099] Exemplarily, IN is used to represent the current flowing through the lithium iron battery before the adjustable resistor is connected in parallel, and In is used to represent the current flowing through the adjustable resistor after the adjustable resistor is connected in parallel. The above steps are expressed by the formula:

[0100] In=X+a-IN, IN≥X;

[0101] In=X-IN,Xa≤IN <X;

[0102] In=Xa-IN,X-2a≤IN <X-a;

[0103] In=X-2a-IN,IN <X-2a;

[0104] In a preferred implementation, X=15, a=5.

[0105] The implementation formula of the above step SB223 is:

[0106] Rt = ROUND(Rn*10);

[0107] Rn=VM' / In;

[0108] Among them, Rt is the number of switches that turn on the adjustable resistor, turning on the switch of one adjustable resistor means that the resistance value of the adjustable resistor increases by 0.1 ohms, Rn is the resistance value of the adjustable resistor, VM' is the difference between the cell voltage of the nth lithium battery cell and the second average voltage, In is the current passing through the adjustable resistor after the adjustable resistor is connected in parallel, and ROUND means rounding the number.

[0109] For the above step SB4, the difference between the equivalent voltage and the second average voltage is less than the second threshold value, indicating that the embodiment of the present invention has achieved the purpose of slowing down the charging speed of the nth lithium battery cell by shunting the nth lithium battery cell through the parallel adjustable resistor. At this time, the adjustable resistor connected in parallel in the above steps can be removed from the circuit. In a better implementation, the second threshold value is 0.3. In one embodiment, step SB4 ends the connection relationship between the adjustable resistor and the nth lithium battery cell in step SB2, that is, ends the regulation process, which is the same as the above steps SA41 to SA44, and will not be repeated here.

[0110] For the above-mentioned step SB5, it can be understood that when there is no difference in the first average voltage of the battery cell voltage of the lithium battery cell that is greater than the first threshold value, it indicates that the growth rate of the battery cell voltage of the current lithium battery cell is relatively consistent, thereby achieving the control purpose of reducing the growth rate of the battery cell voltage of the nth lithium battery cell and making the battery voltages converge to consistency during the charging process.

[0111] Another embodiment of the present invention provides a control device based on the standby state of an iron-lithium battery, which is applied to a control processor of the iron-lithium battery control device, wherein the iron-lithium battery control device also includes a lithium battery cell terminal voltage data acquisition module, an iron-lithium battery current acquisition module, a switch array and an adjustable resistor; the control processor executes any of the above iron-lithium battery control methods based on an adjustable resistor.

[0112] like Figure 4 As shown, the embodiment of the present invention further provides a base station power supply system, including a base station power supply device 41 and an iron-lithium battery control device 42;

[0113] The base station power supply device 41 is connected to both ends of the power load, and includes a communication power supply 411 and an iron-lithium battery 412, wherein the iron-lithium battery 412 includes N lithium cells connected in series;

[0114] The iron-lithium battery control device 42 and the iron-lithium battery 412 are both connected to the two ends of the communication power supply 411, and the iron-lithium battery 412 serves as a backup power supply for the communication power supply 411. The communication power supply 411 and the iron-lithium battery 412 both supply power to the communication load, and the communication power supply 411 also supplies power to the iron-lithium battery 412 control device;

[0115] The control processor of the iron-lithium battery control device 42 executes any of the above iron-lithium battery control methods based on an adjustable resistor.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A lithium iron battery control method based on an adjustable resistor, characterized in that: Applicable to a lithium iron battery control device, the lithium iron battery control device comprises a lithium battery terminal voltage data acquisition module, a lithium iron battery current acquisition module, a switch array, an adjustable resistor and a control processor; the lithium iron battery comprises N lithium batteries connected in series; the lithium battery terminal voltage data acquisition module acquires the battery voltage of each lithium battery, the lithium iron battery current acquisition module acquires the current of the lithium iron battery, the switch array comprises N+1 array switches, the positive electrode of each lithium battery and the negative electrode of each lithium battery are connected to one end of an array switch, Among them, one end of the 2n-1th array switch is connected to the positive electrode of a lithium battery cell, and one end of the 2nth array switch is connected to the negative electrode of the lithium battery cell; the adjustable resistor includes a first positive switch, a second positive switch, a first negative switch and a second negative switch, the first positive switch is connected to the other end of the 2n-1th array switch, the second positive switch is connected to the other end of the 2nth array switch, the first negative switch is connected to the other end of the 2n-1th array switch, and the second negative switch is connected to the other end of the 2nth array switch; The iron-lithium battery control method based on the adjustable resistor includes: SA1. When the lithium iron battery is in standby mode, the cell voltage of each lithium battery cell is measured; SA2. If the cell voltage of the nth lithium battery cell is greater than a preset voltage value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium battery cells, the first positive switch, the second positive switch, the first negative switch, the second negative switch and N+1 array switches of the adjustable resistor are adjusted so that the adjustable resistor is connected in series with the nth lithium battery cell, and the resistance value of the adjustable resistor is calculated and set by a first resistance control function; wherein N is a positive integer, and n is a positive integer less than or equal to N; SA3, measuring the target voltage of the nth lithium battery cell after the nth lithium battery cell is connected in series with the adjustable resistor set in SA2; SA4. If the target voltage is less than or equal to a preset voltage value, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell; if the target voltage is greater than the preset voltage value, the connection relationship between the adjustable resistor and the nth lithium battery cell is maintained; SA5. Repeat SA1 to SA4 until the cell voltage of any lithium battery cell is less than or equal to the preset voltage value.

2. The iron-lithium battery control method based on an adjustable resistor as claimed in claim 1, characterized in that: The method of adjusting the first positive switch, the second positive switch, the first negative switch, the second negative switch and N+1 array switches of the adjustable resistor so that the adjustable resistor is connected in series with the nth lithium battery cell includes: If the serial number of the nth lithium battery cell is an odd number, the first positive switch and the second negative switch are controlled to be closed, and the resistance value of the adjustable resistor is adjusted to a maximum resistance value; After adjusting to the maximum resistance value, the first array switch and the fourth array switch are controlled to be closed, and it is detected whether the first multiple connection line is the positive pole and the second multiple connection line is the negative pole. If so, the first array switch and the fourth array switch are controlled to be opened, and the 2n-1th array switch and the 2nth array switch are controlled to be closed; it is detected again whether the first multiple connection line is the positive pole and the second multiple connection line is the negative pole. If so, the 2n-1th array switch and the 2nth array switch are kept closed, so that the adjustable resistor is connected in series with the nth lithium battery cell; If the serial number of the nth lithium battery cell is an even number, the second positive switch and the first negative switch are controlled to be closed, and the resistance value of the adjustable resistor is adjusted to a maximum resistance value; After adjusting to the maximum resistance value, the second array switch and the third array switch are controlled to be closed, and it is detected whether the first multiple connection line is the negative pole and the second multiple connection line is the positive pole. If so, the second array switch and the third array switch are controlled to be opened, and the 2nth array switch and the 2n+1th array switch are controlled to be closed; it is detected again whether the first multiple connection line is the negative pole and the second multiple connection line is the positive pole. If so, the 2nth array switch and the 2n+1th array switch are kept closed, so that the adjustable resistor is connected in series with the nth lithium battery cell; The connection between the first positive switch, the second positive switch and the array switch of the adjustable resistor is a first complex connection; the connection between the first negative switch, the second negative switch and the array switch of the adjustable resistor is a second complex connection.

3. The iron-lithium battery control method based on adjustable resistor according to claim 2, characterized in that: When the serial number of the nth lithium battery cell is odd, if the condition that the first multiple connection line is positive and the second multiple connection line is negative is not met, a wiring error is reported; When the serial number of the nth lithium battery cell is an even number, if the condition that the first multiple connection line is the negative pole and the second multiple connection line is the positive pole is not met, a wiring error is reported.

4. The iron-lithium battery control method based on adjustable resistor according to claim 1, characterized in that: The first resistance control function is as follows: Rt = ROUND(Rn*10); Rn=VM / 5; Wherein, Rt is the number of switches that open the adjustable resistor. Opening a switch of the adjustable resistor means that the resistance value of the adjustable resistor increases by 0.1 ohms. Rn is the resistance value of the adjustable resistor. VM is the difference between the cell voltage of the nth lithium battery cell and the discharge termination voltage.

5. The iron-lithium battery control method based on adjustable resistor according to claim 1, characterized in that: The preset voltage value is calculated according to the discharge termination voltage of the iron-lithium battery.

6. The iron-lithium battery control method based on an adjustable resistor according to any one of claims 1 to 5, characterized in that: Adjusting the positive switch, the negative switch and the array switch of the adjustable resistor to terminate the connection between the adjustable resistor and the nth lithium battery cell includes: If the serial number of the nth lithium battery cell is an odd number, turn on the 2n-1th array switch and the 2nth array switch to adjust the resistance value of the adjustable resistor to the maximum; After adjusting to the maximum resistance value, detecting whether there is voltage between the first multiple connection line and the second multiple connection line, and if so, turning on the first positive switch and the second negative switch to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell; If the serial number of the nth lithium battery cell is an even number, the 2nth array switch and the 2n+1th array switch are turned on to adjust the resistance value of the adjustable resistor to the maximum; After adjusting to the maximum resistance value, detecting whether there is voltage between the first multiple connection line and the second multiple connection line, and if so, turning on the second positive switch and the first negative switch to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell; The connection between the first positive switch, the second positive switch and the array switch of the adjustable resistor is a first complex connection; the connection between the first negative switch, the second negative switch and the array switch of the adjustable resistor is a second complex connection.

7. The iron-lithium battery control method based on adjustable resistor according to claim 1, characterized in that: Also includes: SB1. When the lithium iron battery is in a charging state, measure the cell voltage of each lithium battery cell, and calculate a first average voltage based on N lithium battery cells, and a difference between the cell voltage of each lithium battery cell and the first average voltage; SB2. If the difference between the cell voltage of the nth lithium battery cell and the first average voltage is greater than the first threshold value, and the cell voltage of the nth lithium battery cell is higher than the cell voltages of the remaining lithium batteries, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted so that the adjustable resistor is connected in parallel with the nth lithium battery cell, and the resistance value of the adjustable resistor is calculated and set using a second resistance control function; SB3, measuring the target voltage across the nth lithium battery cell after the nth lithium battery cell is connected in parallel with the adjustable resistor set in SB2, and calculating the second average voltage based on the target voltage and the cell voltages of the remaining lithium batteries measured in SB1, and the difference between the target voltage and the second average voltage; SB4. If the difference between the target voltage and the second average voltage is less than a second threshold, the first positive switch, the second positive switch, the first negative switch, the second negative switch and the N+1 array switches of the adjustable resistor are adjusted to terminate the connection between the adjustable resistor and the nth lithium battery cell; if the difference between the target voltage and the second average voltage is greater than or equal to the second threshold, the connection between the adjustable resistor and the nth lithium battery cell is maintained; SB5. Repeat steps SB1 to SB4 until the difference between the cell voltage of any lithium battery cell and the first average voltage is less than or equal to the first threshold.

8. A control device based on the standby state of a lithium iron battery, characterized in that: A control processor applied to a lithium iron battery control device, wherein the lithium iron battery control device also includes a lithium battery cell terminal voltage data acquisition module, a lithium iron battery current acquisition module, a switch array and an adjustable resistor; the control processor executes the lithium iron battery control method based on the adjustable resistor as described in any one of claims 1 to 7.

9. A base station power supply system, characterized in that: Including base station power supply device and iron-lithium battery control device; The base station power supply device is connected to both ends of the power load, including a communication power supply and an iron-lithium battery, wherein the iron-lithium battery includes N lithium cells connected in series; The iron-lithium battery control device and the iron-lithium battery are both connected to the two ends of the communication power supply, the iron-lithium battery serves as a backup power supply for the communication power supply, the communication power supply and the iron-lithium battery both supply power to the communication load, and the communication power supply also supplies power to the iron-lithium battery control device; The control processor of the iron-lithium battery control device executes the iron-lithium battery control method based on an adjustable resistor as described in any one of claims 1 to 7.

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