Control method and device based on charging state of lithium iron battery and base station power supply device

Abstract

The present invention provides a control method and device based on the charging state of a lithium iron battery and a base station power supply device. The method includes measuring the cell voltage of each lithium battery cell when the lithium iron battery is in a charging state, judging and locking the lithium battery cell with a faster charging speed through a first threshold, and processing the lithium battery cell with the fastest charging speed in turn and cyclically until all lithium batteries are not charged too fast. The present invention solves the problem that when the lithium iron battery is used as a backup power source, the charging speed of individual batteries is relatively fast, resulting in a decrease in the performance of the entire lithium iron battery and a significant shortening of its life.

Description

Technical Field

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

[0002] Communication base stations generally use lithium iron batteries as backup power sources to ensure that the communication base stations can continue to 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 charging lithium iron batteries, the charging speed of each battery cell is usually different. Based on the above two prerequisites, it is easy for some batteries to reach the full charge state too early. In this case, the batteries that are fully charged too early may experience more charge and discharge cycles, causing the battery to age faster. In the long run, the performance of the entire lithium iron battery will decline and the life span 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 based on the charging state of an iron-lithium battery, which solves the problem in the prior art that when the iron-lithium battery is used as a backup power source, the individual cells are charged too fast, resulting in a decrease in the performance of the entire iron-lithium battery and a significantly shortened lifespan.

[0005] According to an embodiment of the present invention, a first aspect provides a control method based on the charging state of an iron-lithium battery, 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 ... 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 control method based on the charging state of the iron-lithium battery includes:

[0007] S1. 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 batteries, and a difference between the cell voltage of each lithium battery cell and the first average voltage;

[0008] S2. 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 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 resistance control function; wherein N is a positive integer, and n is a positive integer less than or equal to N;

[0009] S3, 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 S2, and calculating the second average voltage based on the target voltage and the cell voltages of the remaining lithium batteries measured in S1, and the difference between the target voltage and the second average voltage;

[0010] S4, if the difference between the target voltage and the second average voltage is less than a second threshold, adjusting 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 to terminate the connection relationship 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, maintaining the connection relationship between the adjustable resistor and the nth lithium battery cell;

[0011] S5. Repeat S1 to S4 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.

[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 parallel 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 positive and the second multiple connection line is negative. If so, the first array switch and the fourth array switch are controlled to be opened, and the 2n-1 array switch and the 2n array switch are controlled to be closed; it is detected again whether the first multiple connection line is positive and the second multiple connection line is negative. If so, the first positive switch, the second negative switch, the 2n-1 array switch and the 2n array switch are kept closed, so that the adjustable resistor is connected in parallel 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 second positive pole switch, the first negative pole switch, the 2nth array switch and the 2n+1th array switch are kept closed, so that the adjustable resistor is connected in parallel 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 a positive electrode and the second multiple connection line is a negative electrode 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, calculating the resistance value of the adjustable resistor using a resistance control function includes:

[0021] Obtaining the current flowing through the lithium iron battery collected by the current collection module of the lithium iron battery before the adjustable resistor is connected in parallel;

[0022] According to the current flowing through the lithium iron battery before the adjustable resistor is connected in parallel, the current flowing through the adjustable resistor after the adjustable resistor is connected in parallel is predicted;

[0023] Substitute the difference between the cell voltage of the nth lithium 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.

[0024] Optionally, according to the current flowing through the lithium iron battery before the adjustable resistor is connected in parallel, predicting the current flowing through the adjustable resistor after the adjustable resistor is connected in parallel includes:

[0025] 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;

[0026] 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;

[0027] 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;

[0028] 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.

[0029] Optionally, 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, are substituted into the resistance control function to calculate the resistance value of the adjustable resistor, and the formula is:

[0030] Rt = ROUND(Rn*10);

[0031] Rn=VM / In;

[0032] 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.

[0033] 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:

[0034] 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;

[0035] 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;

[0036] 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;

[0037] 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;

[0038] 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.

[0039] The second aspect provides a control device based on the charging state of a lithium iron battery, which is applied to a control processor of the 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 a control method based on the charging state of a lithium iron battery as described in any one of claims 1 to 7.

[0040] A third aspect provides a base station power supply system, including a base station power supply device and an iron-lithium battery control device;

[0041] 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;

[0042] 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;

[0043] The control processor of the iron-lithium battery control device executes the control method based on the charging state of the iron-lithium battery as described in any one of claims 1 to 7.

[0044] The present invention has the following beneficial effects: when the iron-lithium battery is in a charging state, the cell voltage of each lithium battery cell is measured, the lithium battery cell with a faster charging speed is judged and locked by a first threshold value, and the lithium battery cell with the fastest charging speed is processed in turn and cyclically until all lithium batteries are not charged too fast. The processing method is: control the array switch and the first positive switch, the second positive switch, the first negative switch, and the second negative switch of the adjustable resistor, connect the adjustable resistor in parallel with the nth lithium battery cell, realize current shunting, reduce the cell voltage growth rate of the nth lithium battery cell, make the charging speed of each lithium battery cell in the process of charging the iron-lithium battery, and avoid the problem that the charging speed of individual lithium batteries is fast, resulting in the performance decline and significantly shortened life of the entire iron-lithium battery. Then, the second threshold is used to determine whether the regulation of the nth lithium battery cell has achieved the purpose. If there is no need to further reduce its voltage growth rate, 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, to terminate the connection relationship between the adjustable resistor and the nth lithium battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the implementation flow of the control method based on the charging state of the iron-lithium battery according to an embodiment of the present invention;

[0046] Figure 2 A structural diagram of a lithium iron battery control device according to another embodiment of the present invention;

[0047] Figure 3 This is a structural diagram of a base station power supply system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0049] like Figure 1 As shown, the embodiment of the present invention proposes a control method based on the charging state of a lithium iron battery, 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.

[0050] 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 nThe 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.

[0051] Based on this, Figure 1 As shown, the control method based on the charging state of the iron-lithium battery includes but is not limited to the following steps:

[0052] S1. 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 batteries, and a difference between the cell voltage of each lithium battery cell and the first average voltage;

[0053] S2. 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 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 resistance control function; wherein N is a positive integer, and n is a positive integer less than or equal to N;

[0054] S3, 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 S2, and calculating the second average voltage based on the target voltage and the cell voltages of the remaining lithium batteries measured in S1, and the difference between the target voltage and the second average voltage;

[0055] S4, if the difference between the target voltage and the second average voltage is less than a second threshold, adjusting 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 to terminate the connection relationship 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, maintaining the connection relationship between the adjustable resistor and the nth lithium battery cell;

[0056] S5. Repeat S1 to S4 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.

[0057] For the above step S1, 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 S3 is associated here for comparative explanation, wherein the second average voltage in step S3 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 S1 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 S2, 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 S3 is b2', the second average voltage in S3 is (b1+b2'+b3+b4) / 4.

[0058] For the above step S2, 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.

[0059] In a preferred implementation, the first threshold is 0.1.

[0060] In addition, 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 S2, wherein the conditions specified in step S2 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.

[0061] In one embodiment, based on Figure 2 The iron-lithium battery control device shown in the figure, the above step S2 adjusts 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 to make the adjustable resistor connected in parallel with the nth lithium battery cell, including:

[0062] S211, 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 at the same time adjust the resistance value of the adjustable resistor to a maximum resistance value;

[0063] S212, 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 first positive switch, the second negative switch, the 2n-1th array switch and the 2nth array switch closed, so that the adjustable resistor is connected in parallel with the nth lithium battery cell;

[0064] S213, if the serial number of the nth lithium battery cell is an even number, controlling the second positive switch and the first negative switch to be closed, and adjusting the resistance value of the adjustable resistor to a maximum resistance value;

[0065] S214, 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 second positive pole switch, the first negative pole switch, the 2nth array switch and the 2n+1th array switch closed, so that the adjustable resistor is connected in parallel with the nth lithium battery cell;

[0066] 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.

[0067] It should be noted that in the above steps S211 to S214, 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.

[0068] For the above step S2, the embodiment of the present invention further describes the provided resistance control function, wherein the resistance value of the adjustable resistor is calculated using the resistance control function, including:

[0069] S221, obtaining the current passing through the lithium iron battery collected by the current collection module of the lithium iron battery before the adjustable resistor is connected in parallel;

[0070] S222, predicting the current passing through the adjustable resistor after the adjustable resistor is connected in parallel, based on the current passing through the lithium iron battery before the adjustable resistor is connected in parallel;

[0071] S223, substituting the difference between the cell voltage of the nth lithium battery cell and the first 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.

[0072] In the embodiment of the present invention, the nth lithium battery cell is shunted by connecting an adjustable resistor in parallel. Therefore, the above step S222 is actually to select the current size to be shunted by the adjustable resistor according to the current passing through the lithium iron battery before the adjustable resistor is connected in parallel. Based on this, the detailed implementation of the above step S222 includes:

[0073] 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;

[0074] 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;

[0075] 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;

[0076] 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.

[0077] 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:

[0078] In=X+a-IN, IN≥X;

[0079] In=X-IN,Xa≤IN <X;

[0080] In=Xa-IN,X-2a≤IN <X-a;

[0081] In=X-2a-IN,IN <X-2a;

[0082] In a preferred implementation, X=15, a=5.

[0083] The implementation formula of the above step S223 is:

[0084] Rt = ROUND(Rn*10);

[0085] Rn=VM / In;

[0086] 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.

[0087] For the above step S4, the difference between the target 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 shunting the nth lithium battery cell by connecting an adjustable resistor in parallel, thereby slowing down its charging speed. At this time, the adjustable resistor connected in parallel in the above step can be removed from the circuit.

[0088] In a preferred implementation, the second threshold is 0.3.

[0089] It should be noted that the adjustment in the above step S2 causes the rate of increase of the cell voltage of the nth lithium battery cell to gradually decrease. The target voltage across the nth lithium battery cell shown in the above step S3 is the result of real-time monitoring. Therefore, the adjustment in the above step S2 is a process in which the difference between the cell voltage of the nth lithium battery cell and the first average voltage gradually approaches 0 from a positive value. When the cell voltage of the nth lithium battery cell is adjusted too low, the difference between the target voltage and the second average voltage gradually approaches 0 and is less than 0. Therefore, the embodiment of the present invention also avoids the above-mentioned over-adjustment through a second threshold.

[0090] In one embodiment, step S4 ends the connection between the adjustable resistor and the nth lithium battery cell in step S2, that is, ends the regulation process, and includes:

[0091] S41, 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;

[0092] S42, 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;

[0093] S43, 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 value of the adjustable resistor to the maximum;

[0094] S44, 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;

[0095] 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.

[0096] For the above step S5, 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 means 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 cell voltages converge to consistency during the charging process.

[0097] Another embodiment of the present invention provides a control device based on the charging state of a lithium iron battery, which is applied to a control processor of the 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 any of the above control methods based on the charging state of the lithium iron battery.

[0098] like Figure 3 As shown, the embodiment of the present invention further provides a base station power supply system, including a base station power supply device 31 and an iron-lithium battery control device 32;

[0099] The base station power supply device 31 is connected to both ends of the power load, and includes a communication power supply 311 and an iron-lithium battery 312, wherein the iron-lithium battery 312 includes N lithium cells connected in series;

[0100] The iron-lithium battery control device 32 and the iron-lithium battery 312 are both connected to the two ends of the communication power supply 311, and the iron-lithium battery 312 serves as a backup power supply for the communication power supply 311. The communication power supply 311 and the iron-lithium battery 312 both supply power to the communication load, and the communication power supply 311 also supplies power to the iron-lithium battery 312 control device;

[0101] The control processor of the iron-lithium battery control device 32 executes any of the above control methods based on the charging state of the iron-lithium battery.

[0102] 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 control method based on the charging state of a lithium iron battery, 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 control method based on the charging state of the iron-lithium battery includes: S1. 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 batteries, and a difference between the cell voltage of each lithium battery cell and the first average voltage; S2. 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 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 resistance control function; wherein N is a positive integer, and n is a positive integer less than or equal to N; S3, 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 S2, and calculating the second average voltage based on the target voltage and the cell voltages of the remaining lithium batteries measured in S1, and the difference between the target voltage and the second average voltage; S4, if the difference between the target voltage and the second average voltage is less than a second threshold, adjusting 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 to terminate the connection relationship 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, maintaining the connection relationship between the adjustable resistor and the nth lithium battery cell; S5. Repeat S1 to S4 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.

2. The control method based on the charging state of the iron-lithium battery according to claim 1, characterized in that: The step 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 parallel 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 positive and the second multiple connection line is negative. If so, the first array switch and the fourth array switch are controlled to be opened, and the 2n-1 array switch and the 2n array switch are controlled to be closed; it is detected again whether the first multiple connection line is positive and the second multiple connection line is negative. If so, the first positive switch, the second negative switch, the 2n-1 array switch and the 2n array switch are kept closed, so that the adjustable resistor is connected in parallel 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 second positive pole switch, the first negative pole switch, the 2nth array switch and the 2n+1th array switch are kept closed, so that the adjustable resistor is connected in parallel 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 control method based on the charging state of the iron-lithium battery 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 control method based on the charging state of the iron-lithium battery according to claim 2, characterized in that: The resistance value of the adjustable resistor is calculated using a resistance control function, including: Obtaining the current flowing through the lithium iron battery collected by the current collection module of the lithium iron battery before the adjustable resistor is connected in parallel; According to the current flowing through the lithium iron battery before the adjustable resistor is connected in parallel, the current flowing through the adjustable resistor after the adjustable resistor is connected in parallel is predicted; Substitute the difference between the cell voltage of the nth lithium battery cell and the first 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.

5. The control method based on the charging state of the iron-lithium battery according to claim 4, characterized in that: According to the current of the lithium iron battery before the adjustable resistor is connected in parallel, the current of the adjustable resistor after the adjustable resistor is connected in parallel is predicted, including: 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; 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; 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; 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.

6. The control method based on the charging state of the iron-lithium battery according to claim 5, characterized in that: Substitute the difference between the cell voltage of the nth lithium battery cell and the first 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, and the formula is: Rt = ROUND(Rn*10); Rn=VM / In; 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 first 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.

7. The control method based on the charging state of the iron-lithium battery according to any one of claims 1 to 6, 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.

8. A control device based on the charging state of a lithium iron battery, characterized in that: A control processor applied to a lithium iron battery control device, 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 control method based on the charging state of the lithium iron battery 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 control method based on the charging state of the iron-lithium battery as described in any one of claims 1 to 7.

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