CN112332487A

CN112332487A - Active equalizing charging system for solar battery pack

Info

Publication number: CN112332487A
Application number: CN202011219329.9A
Authority: CN
Inventors: 尹振坤; 熊杰; 彭磊; 白小强; 易超
Original assignee: Socreat Electronics Technology Ltd
Current assignee: Shenzhen Yuanyuan Intelligent Lighting Co.,Ltd.
Priority date: 2020-11-04
Filing date: 2020-11-04
Publication date: 2021-02-05

Abstract

The invention relates to the technical field of batteries, in particular to an active equalizing charging system of a solar battery pack, which comprises a voltage acquisition module, a switch module, a charging protection module, a control module and a battery pack, wherein the voltage acquisition module is connected with the switch module; when the voltage of one battery is higher than a preset equalizing starting voltage and the voltage difference between the battery and the battery with the lowest voltage in the battery pack is higher than a preset voltage difference, controlling the charging protection module corresponding to the battery to be disconnected and the switch module to be switched on to equalize charging, wherein the preset equalizing starting voltage can be dynamically adjusted; the equalization mode does not need to discharge the batteries, can avoid the problem of too large loss in the equalization process, and can also avoid the reduction of the capacity and the service life of the battery pack caused by over-discharge of the batteries.

Description

Active equalizing charging system for solar battery pack

Technical Field

The invention relates to the technical field of batteries, in particular to an active equalizing charging system of a solar battery pack.

Background

Usually, a plurality of batteries are connected in series to form a power battery pack, and even if the inconsistency among the battery units caused by manufacturing reasons is neglected, the inconsistency is more serious due to the influences of temperature, internal resistance and aging in the working process, so that the voltage of the battery pack is unbalanced. The overcharge and overdischarge phenomena can be caused in the charging and discharging process, the cycle service life of the battery pack is finally influenced, and the battery pack fails in advance. In order to prolong the cycle service life of the power battery pack, an effective measure is to perform balance control on the battery pack.

The existing equalization control of the battery pack is to collect the actual voltage value of each string of batteries in the battery pack, compare the collected actual voltage value with a fixed voltage range to judge the string of batteries exceeding the fixed voltage, and control the over-voltage string of batteries to discharge or not to charge, thereby achieving the equalization charging of each string of batteries.

However, the balance control causes too much loss in system balance due to the discharge process of the battery, and simultaneously, the over-discharge of the battery is easily caused to affect the reduction of the capacity and the service life of the battery pack. Particularly, in the case of solar charging, since the sunshine time is short and the charging time is limited, the battery pack is too large in loss during equalization, the charging efficiency is low, and the battery consistency is poor.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide an active equalizing charging system for a solar cell set, which overcomes the disadvantages of large equalizing loss, low charging efficiency and poor battery consistency in the existing battery equalizing control.

The invention provides a solar battery pack active equalizing charging system, which comprises: the charging device comprises a battery pack, a voltage acquisition module, a charging protection module, a switch module and a control module, wherein the battery pack is connected with an external power supply to form a charging circuit and comprises a plurality of batteries connected in series; the voltage acquisition modules are connected with the batteries in a one-to-one correspondence manner and used for acquiring the voltage of each string of batteries in the battery pack; the charging protection module is connected between two adjacent batteries in series, each string of batteries is provided with one charging protection module, and the charging protection module is used for switching on or switching off the charging circuit; the switch module is connected in parallel with the battery and the charging protection module, each string of batteries is provided with one switch module, and the switch modules are used for providing a path when the charging circuit is disconnected; the control module is connected with the voltage acquisition module, the charging protection module and the switch module and is used for controlling the charging protection module and the switch module to be switched on or switched off according to the acquired voltage of each string of batteries; when the voltage of one battery is higher than a preset equalizing starting voltage and the voltage difference between the battery and the battery with the lowest voltage in the battery pack is higher than a preset voltage difference, the charging protection module is controlled to be disconnected and the switch module is controlled to be switched on to equalize the charging, wherein the preset equalizing starting voltage can be dynamically adjusted.

Further, the preset equalizing start voltage is adjusted to be decreased or increased according to the voltage difference between the battery and the battery with the lowest voltage in the battery pack.

Further, the preset equalizing start voltage is adjusted to be decreased or increased according to the voltage difference between the total voltage of all the batteries in the battery pack and the preset total voltage.

Further, the battery pack is charged in a charging mode with the maximum power, wherein the power of the charging mode comprises: charging power at the time of equalizing charging, constant voltage charging power, and constant current charging power.

Furthermore, the charging protection module comprises a charging protection chip and a first MOS transistor, the first MOS transistor is connected with the battery, and the first MOS transistor is further connected with the charging protection chip and the control module respectively; the charging protection chip is used for detecting the voltage of the battery and outputting high and low levels according to the voltage of the battery so as to control the on-off of the first MOS tube.

Further, the charging protection module further includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a first triode, and a second triode; the battery is connected between the charging protection chip and the first MOS tube; an emitting electrode of the first triode is connected between the battery and a drain electrode of the first MOS tube, a collector electrode of the first triode is connected with one end of the thirteenth resistor, and the other end of the thirteenth resistor is connected with the charging protection chip; a base electrode of the first triode is connected with one end of the fourteenth resistor, and the other end of the fourteenth resistor is connected with the control module; one end of the fifteenth resistor is connected between the first triode and the fourteenth resistor, and the other end of the fifteenth resistor is connected with the emitter of the first triode and the drain of the first MOS tube; the source electrode of the first MOS tube is grounded, the grid electrode of the first MOS tube is connected with one end of the seventeenth resistor, the other end of the seventeenth resistor is connected with one end of the sixteenth resistor, and the other end of the sixteenth resistor is connected with the charging protection chip; a collector of the second triode is connected between the sixteenth resistor and the seventeenth resistor, and an emitter of the second diode is connected with a source of the first MOS tube; one end of the eighteenth resistor is connected between the first MOS tube and the second diode, and the other end of the eighteenth resistor is connected with the base electrode of the second diode; one end of the nineteenth resistor is connected between the base electrode of the second diode and the eighteenth resistor, and the other end of the nineteenth resistor is connected to the control module; one end of the twentieth resistor is connected with the charging protection chip, and the other end of the twentieth resistor is grounded.

Furthermore, the switch module comprises a second MOS transistor and a third resistor, a gate of the second MOS transistor is connected with one end of the third resistor, the other end of the third resistor is connected with the control module, and a source of the second MOS transistor is connected with a source of the first MOS transistor; the drain electrode of the second MOS tube is connected with the battery; the switch module further comprises a third MOS tube, the grid electrode of the third MOS tube is connected between the grid electrode of the second MOS tube and the third resistor, the source electrode of the third MOS tube is connected with the source electrode of the second MOS tube, and the drain electrode of the third MOS tube is connected with the drain electrode of the second MOS tube.

Further, the charging device comprises a current adjusting module which is connected between the battery pack and the external power supply, and the current adjusting module is used for acquiring the charging current of the battery pack and increasing or decreasing the charging current according to the comparison result of the acquired charging current and the preset current value of the current adjusting module so as to keep the charging current stable.

Further, the current regulating module comprises a DC-DC circuit, a current sampling circuit, an operational amplifier circuit and a control unit; the DC-DC circuit is connected between the external power supply and the battery pack, the control unit is connected between the DC-DC circuit and the operational amplifier circuit, and the current sampling circuit is connected between the operational amplifier circuit and the battery pack.

Further, still include temperature sampling circuit, it connect in the battery with between the current regulation module, temperature sampling circuit is used for gathering the temperature of group battery and output temperature acquisition result extremely the current regulation module, the current regulation module according to the temperature acquisition result with the comparative result of the preset temperature value of current regulation module adjusts charging current.

The charging protection circuit has the advantages that the voltage of each battery string is collected by the voltage collection module and output to the control module, and the control module controls the switch module and the charging protection module to be switched on and off according to the voltage collection result so as to control each battery string to be switched off for charging or switched in the charging circuit to realize equalizing charging. Meanwhile, due to the fact that the preset equalizing starting voltage for controlling the equalizing charge can be dynamically adjusted, the equalizing mode does not need to discharge the batteries, the problem that the loss is too large in the equalizing process can be solved, meanwhile, the reduction of the capacity and the service life of the battery pack caused by over-discharge of the batteries can also be avoided, the batteries can enter the equalizing charge in advance under the condition that the sunshine time is limited, each string of batteries can be charged with enough electric quantity, the equalizing loss is reduced, the charging efficiency is high, the charging is more balanced, and the consistency is good.

Drawings

FIG. 1 is a schematic diagram of an active equalizing charge system for solar cell arrays according to the present invention;

FIG. 2 is a schematic diagram of the connection relationship between the battery pack and the charging protection module of the active equalizing charging system for solar battery pack according to the present invention;

FIG. 3 is a schematic diagram of a voltage acquisition module of the active equalizing charge system of the solar cell array according to the present invention;

FIG. 4 is a schematic diagram of a current sampling circuit of the active equalizing charge system of the solar cell set of the present invention;

FIG. 5 is a schematic diagram of an operational amplifier circuit of the active equalizing charge system of the solar cell set according to the present invention;

FIG. 6 is a schematic diagram of a charge protection module of the active equalizing charge system of solar cell set according to the present invention;

FIG. 7 is a schematic diagram of a temperature sampling circuit of the active equalizing charge system of the solar cell set of the present invention;

fig. 8 is a schematic diagram of a switch module of the active equalizing charge system of solar battery pack according to the present invention.

The correspondence between reference numbers and names is as follows: the solar battery pack active equalizing charging system 1; a voltage acquisition module 10; a first diode D1; a second diode D2; a first capacitance C1; a first resistor R1; a second resistor R2; a switch module 20; a charging protection module 30; thirteen resistors R13; a fourteenth resistance R14; a fifteenth resistor R15; a sixteenth resistor R16; a seventeenth resistor R17; an eighteenth resistor R18; a nineteenth resistor R19; a twentieth resistor R20; a twenty-first resistor R21; a fifth capacitance C5; a first transistor Q1; a second transistor Q2; a charging protection chip U1; a first MOS transistor S1; a second MOS transistor S2; a third MOS transistor S3; a third resistor R3; a control module 40; a battery pack 50; a current regulation module 60; a DC-DC circuit 601; a current sampling circuit 602; a fourth resistor R4; a fifth resistor R5; an operational amplifier circuit 603; a sixth resistor R6; a seventh resistor R7; an eighth resistor R8; a ninth resistor R9; a tenth resistor R10; an eleventh resistor R11; a twelfth resistor R12; a second capacitance C2; a third capacitance C3; a fourth capacitance C4; an operational amplifier U2; a control unit 604; a temperature sampling circuit 70; a temperature probe 701; a twenty-first resistor R21; a twenty-second resistor R22; a sixth capacitance C6; a third diode D3; and a fourth diode D4.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The embodiment of the invention provides an active equalizing charge system 1 for a solar battery pack, as shown in fig. 1 and 2, which is used for equalizing charge management of the battery pack 50 and comprises a battery pack 50, a voltage acquisition module 10, a charge protection module 30, a switch module 20 and a control module 40; the battery pack 50 is connected with an external power supply to form a charging circuit, and the battery pack 50 comprises a plurality of strings of batteries connected in series; the voltage acquisition modules 10 are connected with the batteries in a one-to-one correspondence manner and are used for acquiring the voltage of each string of batteries in the battery pack 50; the charging protection module 30 is connected in series between two adjacent batteries, and each string of batteries is configured with one charging protection module 30, and the charging protection module 30 is used for switching on or switching off the charging circuit; the switch module 20 is connected in parallel to the battery and the charging protection module 30, and each string of the batteries is configured with one switch module 20, and the switch module 20 is used for providing a path when the charging circuit is disconnected; the control module 40 is connected to the voltage acquisition module 10, the charging protection module 30 and the switch module 20, and the control module 40 is configured to control the charging protection module 30 and the switch module 20 to be turned on or off according to the acquired voltage of each string of the batteries; when the voltage of one battery is higher than a preset equalizing starting voltage and the voltage difference between the battery and the battery with the lowest voltage in the battery pack is higher than a preset voltage difference, the charging protection module 30 corresponding to the battery is controlled to be switched off and the switch module 20 is controlled to be switched on to equalize the charging, wherein the preset equalizing starting voltage can be dynamically adjusted.

In specific implementation, the battery pack 50 includes a first string of batteries, a second string of batteries, … …, and an nth string of batteries connected in series, the corresponding switch modules 20 are respectively a first switch module, a second switch module, … …, and an nth switch module, and the corresponding charging protection modules 30 are respectively a first charging protection module, a second charging protection module, … …, and an nth charging protection module 30; when the battery pack is used, the battery pack 50 is connected to an external power supply to start charging, the charging protection module 30 is in a connected state, the switch module 20 is in a disconnected state, and at the moment, charging current flows from the external power supply through the first string of batteries, the first charging protection module, the second string of batteries, the second charging protection module, … …, the Nth string of batteries and the Nth charging protection module in sequence; when the control module 40 determines that a certain string or strings of batteries need to stop charging according to the voltage acquisition result of each string of batteries, assuming that the control module 40 determines that a second string of batteries needs to stop charging, the control module 40 controls a second charging protection module corresponding to the second string of batteries to be turned off, and simultaneously a second switch module corresponding to the second string of batteries is turned on, at this time, the second string of batteries is turned off from the charging circuit, and the other strings of batteries continue to be charged due to the turn-on of the second switch module 20, that is, the charging current sequentially flows through the first string of batteries, the first charging protection module, the second switch module, the third string of batteries, the third charging protection module … …, the nth string of batteries, and the nth charging protection module from the external power supply; when the control module 40 judges that the second string of batteries meets the reconnection condition according to the voltage acquisition result of each string of batteries, the control module 40 controls the second charging protection module to be switched on and simultaneously controls the second switch module to be switched off, at this moment, the second string of batteries is reconnected to the charging circuit to continue charging, namely, the charging current flows through the first string of batteries, the first charging protection module, the second string of batteries, the second charging protection module, … …, the Nth string of batteries and the Nth charging protection module from an external power supply in sequence.

The voltage of each string of batteries is collected by the voltage collecting module 10 and output to the control module 40, the control module 40 controls the switch-on and switch-off of the switch module 20 and the charging protection module 30 according to the voltage collecting result so as to control each string of batteries to be disconnected from charging or connected into a charging circuit, and in such a balancing mode, the batteries do not need to be discharged, so that the problem of too large loss in the balancing process can be avoided, and the problem of reduction of the battery pack capacity and the service life caused by over-discharge of the batteries can be avoided.

The control module 40 controls the switch module 20 to be turned on or off according to the voltage acquisition result, and may adopt the following control modes:

(1) comparing the voltage U of each string of batteries_XAnd preset equalized starting voltage U_iIf U is present_X＜U_iThen the sum of the voltages U of all the battery packs 50 in the charged state is compared_sumAnd a preset total voltage U_maxIf U is present_sum≥U_maxIf the charging is stopped, the control module 40 controls the main charging circuit to be disconnected and stops charging all the battery packs 50;

(2) if U is present_X＜U_iAnd U is_sum＜U_maxThe entire charging loop continues to maintain charging while continuing to compare the voltage U of each string of cells_XAnd a set voltage value U_i；

(3) If U is present_X≥U_iThe control system determines the lowest voltage U between the battery packs 50_minThen comparing the voltage values U of the other strings of batteries_XAnd the lowest voltage U_minIs compared with a set differential pressure value U_oIf U is present_X-U_min＜U_oThen the sum of the voltages U of all the battery packs 50 in the charged state is compared_sumAnd a preset total voltage U_maxIf U is present_sum≥U_maxIf the charging is stopped, the control module 40 controls the main charging circuit to be disconnected and stops charging all the battery packs 50;

(4) if U is present_X≥U_iAnd U is_X-U_min＜U_oAnd U is_sum＜U_maxThe entire charging loop continues to maintain charging while continuing to compare the voltage U of each string of cells_XAnd a set voltage value U_i；

(5) If U is present_X≥U_iAnd U is_X-U_min≥U_oThen the control module 40 controls the minimum voltage U_minPressure difference of more than U_oIs turned on to the lowest voltage U_minPressure difference of more than U_oElectricity (D) fromStopping charging when the battery is disconnected, and normally charging other batteries;

(6) when the voltage difference between the voltage of the battery stopped from charging and the lowest voltage of the battery in the charged state is less than U_oIn the meantime, the control module 40 controls the corresponding switch module 20 to be turned on, and the battery which is stopped to be charged is connected to the charging circuit again to be charged until the U is detected_sum≥U_max。

It should be noted that there are many ways to dynamically adjust the preset equalizing start voltage, and the following description will be given by referring to preferred embodiments.

In an embodiment, the preset equalizing start voltage is adjusted to decrease or increase according to a voltage difference between the battery and a battery with the lowest voltage in the battery pack.

Specifically, when the voltage of one string of batteries in the strings reaches the preset equalization start voltage, which may be afternoon, the system enters a constant voltage charging stage at this time, the charging current is small, the equalization effect is poor or cannot be achieved, and particularly, the difference between the voltage differences is large. Therefore, in the embodiment, the preset equalization starting voltage is properly reduced under the condition of large differential pressure according to the differential pressure between each string of batteries, so that the system enters equalization in advance. Under the condition of limited sunshine, the unbalanced batteries are supplemented with electricity in advance, and the batteries to be balanced are supplemented with more capacity. In addition, the system enters into equalization in advance, when sunlight is still sufficient, the equalizing plate is in a constant-current charging stage at the time, the charging current is large, the equalizing effect is better, the equalizing time is shorter, and the charging speed is higher.

Further, after the preset equalizing start voltage is adjusted and decreased, the preset equalizing start voltage needs to be adjusted and increased. Because the system will always equalize ahead of time without increasing back, the charging power at this time is not necessarily the maximum charging power. Therefore, the preset equalizing start voltage is adjusted according to the voltage difference of the battery, and when the voltage difference of the battery is smaller than the preset voltage difference, the preset equalizing start voltage is increased, so that the system is adjusted to the optimal charging state.

In an embodiment, the preset equalizing start voltage is adjusted to decrease or increase according to a voltage difference between a total voltage of all the batteries in the battery pack and a preset total voltage.

Specifically, most solar street lamp controllers are provided with battery protection functions for being compatible with various types of batteries, and the solar street lamp controllers do not completely depend on the protection functions of the protection plates, but depend on the total voltage of the battery pack for charge and discharge control, so that the problem that the sampling value of the controller (40) and the sampling value of the equalizing plates (10, 20 and the battery pack) are deviated exists. If the sampling of the controller is higher or the sampling of the equalizing plate is lower by a little, the charging of the controller is stopped, but the equalizing plate judges that the voltage of the end point is not reached yet and the equalizing cannot be performed. Therefore, in order to avoid this situation, the present embodiment determines that there is a voltage difference between the total voltage of the battery pack and the preset total voltage, and appropriately reduces the preset equalization start voltage value, so that the battery can complete equalization before the control module determines that the charging is fully charged and is turned off. For example, 2 strings of batteries have an endpoint voltage of 3.65V, the control module determines that the fully charged voltage is set to 7.3V (3.65V × 2 is 7.3V), the control module samples the battery to be higher, the actual voltage of 7.1V determines that the battery is fully charged, one string of the battery packs has a voltage of 3.6V, the other string of the battery packs has a voltage of 3.5V and determines that the battery is fully charged, and the charging is stopped, but the battery does not reach the endpoint voltage and is not equalized, and in this case, the preset equalization start voltage needs to be reduced, so that the battery can be fully charged.

Further, similarly, after the preset equalizing start voltage is adjusted and decreased, the preset equalizing start voltage needs to be adjusted and increased. Specifically, if there is no voltage difference between the total voltage of the battery pack and the preset total voltage, the preset equalizing start voltage is increased.

In one embodiment, the battery pack is charged in a charging mode with the maximum power, wherein the power of the charging mode includes: charging power at the time of equalizing charging, constant voltage charging power, and constant current charging power.

Specifically, since the sun is limited in the daytime, in order to charge the battery pack with more electric quantity as much as possible in the limited daytime, the present embodiment calculates the powers of the different charging modes, and selects the charging mode with the maximum power for charging, thereby further increasing the charging speed and the charging efficiency.

Illustratively, assume a constant current of 20A, for example, two strings of batteries. The terminal voltage of a string of batteries is 3.65V (3.65V is the battery charge protection voltage). The preset equalizing starting voltage can determine whether the system carries out comparison calculation during constant voltage charging or constant current charging. When the two strings of batteries are nearly full, the maximum charging power is 20A × 7.3V — 146W (constant current charging). If the equalization is started to charge a string of batteries at this time, the maximum charging power at this time is 20A × 3.65V — 73W.

Assume that the current of 2 strings of cells entering the constant voltage phase is 15A. The charging power at this time was 15A × 7.3V — 109.5W. The 2 strings of constant voltage charging power 109.3W is greater than the maximum charging power 73W of a string of batteries. The system will continue to charge to below 73W with 2 bursts of constant voltage power and continue the calculation.

Assume that the current of 2 strings of cells entering the constant voltage stage is 9A, and the charging power is 9A × 7.3V — 65.7W. At this time, if a string of batteries is charged in the constant current mode, the maximum charging power is 20A × 3.65V — 73W, 73W >65.7W, so that the system works in the string of constant current charging mode at this time.

When the calculation is performed again, it is possible that 1 string of batteries enters the constant voltage power mode, so the constant voltage charging power of 2 strings of batteries is compared with that of 1 string of batteries. For example, the current of 2 strings at this time is 8A, and the charging constant voltage power of 2 strings is 8A × 7.3V — 58.4W. If a string is charged, the charging current is 18A and the constant voltage of the string is 3.65V. The series charging constant voltage power is 18A × 3.65V ═ 65.7V. 65.7W is greater than 58.4W, so the system charges with 1 string of constant voltage power.

In one embodiment, as shown in fig. 6, the charging protection module 30 includes a charging protection chip U1 and a first MOS transistor S1, the first MOS transistor S1 is connected to the battery, and the first MOS transistor S1 is further connected to the charging protection chip U1 and the control module 40 respectively; the charging protection chip U1 is used for detecting the voltage of the battery and outputting high and low levels according to the voltage of the battery to control the on and off of the first MOS tube S1.

In a specific implementation, when the battery pack 50 is in a charging state, and when the voltage of a certain string or strings of batteries is higher than the protection voltage, assuming that the voltage of a second string of batteries is higher than the protection voltage, the control module 40 sends a control signal to control the first MOS transistor S1 of the second charging protection module to be turned off, and at the same time, the charging protection chip U1 of the second charging protection module also controls the first MOS transistor S1 to be turned off. When in use, the first MOS transistor S1 may be a single first MOS transistor, or may be a plurality of first MOS transistors arranged in parallel, and the plurality of first MOS transistors arranged in parallel may increase current, and those skilled in the art may select the arrangement according to actual needs.

The active control of the control module 40 and the passive control of the charging protection chip U1 act on the first MOS transistor S1 to switch on and off the charging of each string of batteries simultaneously, so that the charging process of each string of batteries is safer, the batteries exceeding the protection voltage can be ensured to be timely switched off and charged to obtain protection, and even when any one of the control module 40 and the charging protection chip U1 breaks down, the batteries exceeding the protection voltage can be controlled to be switched off and charged through the other one.

In an embodiment, with continued reference to fig. 6, the charging protection module 30 further includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a first transistor Q1, and a second transistor Q2; the battery is connected between the charging protection chip U1 and the first MOS tube S1; an emitter of the first triode Q1 is connected between the battery and a drain of the first MOS transistor S1, a collector of the first triode Q1 is connected with one end of the thirteenth resistor R13, and the other end of the thirteenth resistor R13 is connected with the charging protection chip U1; the base of the first triode Q1 is connected to one end of the fourteenth resistor R14, and the other end of the fourteenth resistor R14 is connected to the control module 40; one end of the fifteenth resistor R15 is connected between the first transistor Q1 and the fourteenth resistor R14, and the other end of the fifteenth resistor R15 is connected to the emitter of the first transistor Q1 and the drain of the first MOS transistor S1; the source of the first MOS transistor S1 is grounded, the gate of the first MOS transistor S1 is connected to one end of the seventeenth resistor R17, the other end of the seventeenth resistor R17 is connected to one end of the sixteenth resistor R16, and the other end of the sixteenth resistor R16 is connected to the charging protection chip U1; the collector of the second triode Q2 is connected between the sixteenth resistor R16 and the seventeenth resistor R17, and the emitter of the second diode D2 is connected to the source of the first MOS transistor S1; one end of the eighteenth resistor R18 is connected between the first MOS transistor S1 and the second diode D2, and the other end of the eighteenth resistor R18 is connected to the base of the second diode D2; one end of the nineteenth resistor R19 is connected between the base of the second diode D2 and the eighteenth resistor R18, and the other end of the nineteenth resistor R19 is connected to the control module 40; one end of the twentieth resistor R20 is connected to the charging protection chip U1, and the other end of the twentieth resistor R20 is grounded.

In specific implementation, the charging protection module 30 further includes a fifth capacitor C5 and a twenty-first resistor R21, the fifth capacitor C5 is connected in parallel between the VDD pin and the VSS pin of the charging protection chip U1, the VSS pin of the charging protection chip U1 is grounded, one end of the twenty-first resistor R21 is connected between the fifth capacitor C5 and the VDD pin, and the other end of the twenty-first resistor R21 is connected to a 6.4V power supply; the CS pin of the charging protection chip U1 is connected between the twentieth resistor R20 and the thirteenth resistor R13, and the OC pin of the charging protection chip U1 is connected to the other end of the sixteenth resistor R16.

When the charging circuit is used, if the voltage of the second string of batteries needs to be turned off, the control module 40 and the charging protection chip U1 control the other end of the nineteenth resistor R19 to be at a high level and the other end of the fourteenth resistor R14 to be at a low level, the first MOS transistor S1 is turned off, at this time, the control module 40 controls the switch module 20 to be turned on, so that the second string of batteries is turned off from the charging circuit, and the rest of the batteries continue to be charged; after charging for a period of time, when the second string of batteries does not satisfy the equalization condition and needs to be reconnected to the charging circuit, the control module 40 controls the switch module 20 to be turned off, and simultaneously the control module 40 and the charging protection chip U1 control the other end of the nineteenth resistor R19 to be at a low level and the other end of the fourteenth resistor R14 to be at a high level, the first MOS transistor S1 is turned on, so that the second string of batteries is reconnected to the charging circuit to continue to be charged together with the rest of batteries.

In one embodiment, the voltage acquisition module 10 includes a first diode D1, a second diode D2, a first capacitor C1, a first resistor R1, and a second resistor R2; the cathode of the first diode D1 is connected with a second power supply, the anode of the first diode D1 is connected with the cathode of the second diode D2, and the anode of the second diode D2 is grounded; one end of the first capacitor C1 is connected between the first diode D1 and the second diode D2 and connected with the control module 40, and the other end of the first capacitor C1 is grounded; the second resistor R2 is connected in parallel to two ends of the first capacitor C1; one end of the first resistor R1 is connected between the first capacitor C1 and the second resistor R2, and the other end of the first resistor R1 is connected with a corresponding battery. The voltage acquisition module 10 in this embodiment can acquire the voltages of the battery packs 50 and output the voltage acquisition results to the control module 40. In a specific implementation, the second power supply may be 3.3V.

In an embodiment, as shown in fig. 8, the switch module 20 includes a second MOS transistor S2 and a third resistor R3, a gate of the second MOS transistor S2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to the control module 40, and a source of the second MOS transistor S2 is connected to a source of the first MOS transistor S1; the drain electrode of the second MOS tube S2 is connected with the battery.

In an embodiment, with continued reference to fig. 8, the switch module 20 further includes a third MOS transistor S3, the gate of the third MOS transistor S3 is connected between the gate of the second MOS transistor S2 and the third resistor R3, the source of the third MOS transistor S3 is connected to the source of the second MOS transistor S2, and the drain of the third MOS transistor S3 is connected to the drain of the second MOS transistor S2.

In an embodiment, as shown in fig. 1, the active equalizing charge system further includes a current adjusting module 60 connected between the battery pack 50 and the external power source, wherein the current adjusting module 60 is configured to collect a charge current of the battery pack 50, and increase or decrease the charge current according to a comparison result between the collected charge current and a preset current value of the current adjusting module 60, so as to keep the charge current stable.

In one embodiment, with continued reference to fig. 1, the current regulation module 60 includes a DC-DC circuit 601, a current sampling circuit 602, an operational amplifier circuit 603, and a control unit 604; the DC-DC circuit 601 is connected between the external power source and the battery pack 50, the control unit 604 is connected between the DC-DC circuit 601 and the operational amplifier circuit 603, and the current sampling circuit 602 is connected between the operational amplifier circuit 603 and the battery pack 50; the current sampling circuit 602 is configured to collect a charging current of the battery pack 50, the operational amplifier circuit 603 is configured to amplify the charging current and the preset value to output a feedback current signal, and the control unit 604 compares the feedback current signal with a preset current value to output a step-down or step-up signal to the DC-DC circuit 601 to adjust a charging voltage of the battery pack 50, so as to adjust the charging current of the battery pack 50.

In the process of battery equalization, the number of the batteries in a charging state changes, so that the charging current changes, and through the current adjusting module 60, the charging current of the battery pack 50 can be automatically adjusted, so that the charging current is stable, and the equalization efficiency of the battery pack 50 is improved.

In specific implementation, when the voltage of the second string of batteries is disconnected from the charging circuit, the charging current in the charging circuit is increased, the current sampling circuit 602 collects the increased charging current and feeds the increased charging current back to the operational amplifier circuit 603, the operational amplifier circuit 603 amplifies the received charging current and outputs the amplified charging current to the control unit 604, so that the charging current and the preset current of the control unit 604 are in the same order, the control unit 604 compares the charging current with the preset current and outputs a step-down signal to the DC-DC circuit 601, and the DC-DC circuit 601 steps down and outputs the voltage to the battery pack 50, so that the charging current is reduced to ensure the charging current to be stable; assuming that when the second string of batteries is connected to the charging circuit again, the charging current in the charging circuit is reduced due to the connection of the second string of batteries, the current sampling circuit 602 collects the charging current and then feeds the charging current back to the operational amplifier circuit 603, the operational amplifier circuit 603 amplifies the charging current and then outputs the amplified charging current to the control unit 604, so that the charging current and the preset current of the control unit 604 are in the same order, the control unit 604 compares the charging current with the preset current and then outputs a boost signal to the DC-DC circuit 601, and the DC-DC circuit 601 boosts the charging current and then outputs a voltage to the battery pack 50, thereby boosting the charging current and ensuring the charging current to be stable.

In one embodiment, as shown in fig. 4, the current sampling circuit 602 includes: a fourth resistor R4 and a fifth resistor R5 connected in parallel, wherein one end of the fourth resistor R4 is connected to the battery pack 50, and the other end of the fourth resistor R4 is connected to the operational amplifier circuit 603.

In an embodiment, as shown in fig. 5, the operational amplifier circuit 603 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, and an operational amplifier U2; one end of the sixth resistor R6 is connected between the fourth resistor R4 and the fifth resistor R5, and the other end of the sixth resistor R6 is connected to the non-inverting input end of the operational amplifier U2; one end of the ninth resistor R9 is connected between the sixth resistor R6 and the operational amplifier U2, and the other end of the ninth resistor R9 is grounded; the second capacitor C2 is connected in parallel to two ends of the ninth resistor R9; one end of the tenth resistor R10 is connected between the second capacitor C2 and the non-inverting input terminal of the operational amplifier U2, and the other end of the tenth resistor R10 is connected to a third power supply; one end of the seventh resistor R7 is connected between the fourth resistor R4 and the fifth resistor R5, the other end of the seventh resistor R7 is connected to one end of the eighth resistor R8 and grounded, and the other end of the eighth resistor R8 is connected to the inverting input terminal of the operational amplifier U2; one end of the third capacitor C3 is connected between the operational amplifier U2 and the eighth resistor R8, and the other end of the third capacitor C3 is connected to the output end of the operational amplifier U2; the twelfth resistor R12 is connected in parallel to two ends of the third capacitor C3; one end of the eleventh resistor R11 is connected between the third capacitor C3 and the twelfth resistor R12, and the other end of the eleventh resistor R11 is connected to the control unit 604; one end of the fourth capacitor C4 is grounded, and the other end of the fourth capacitor C4 is connected between the eleventh resistor R11 and the control module 40.

In specific implementation, the third power supply may be 3.3V, and the operational amplifier U2 may be a dual operational amplifier U2, i.e., two operational amplifiers U2 are integrated on a single chip to achieve better performance. When the dual-operational amplifier circuit is used, the first pin of the dual-operational amplifier U2 is the output end of the operational amplifier U2, the second pin of the dual-operational amplifier U2 is the inverting input end of the operational amplifier U2, the third pin of the dual-operational amplifier U2 is the non-inverting input end of the operational amplifier U2, the fourth pin of the dual-operational amplifier U2 is grounded, and the eighth pin of the dual-operational amplifier U2 is connected with a 3.3V power supply. A filter can be connected between the eighth pin of the dual operational amplifier U2 and the 3.3V power supply, the filter is grounded, and the filter can be formed by connecting two capacitors in parallel.

In an embodiment, as shown in fig. 1, the active equalizing charge system further includes a temperature sampling circuit 70 connected between the battery and the current regulating module 60, the temperature sampling circuit 70 is configured to collect a temperature of the battery pack 50 and output a temperature collection result to the current regulating module 60, and the current regulating module 60 regulates the charging current according to a comparison result between the temperature collection result and a preset temperature value of the current regulating module 60.

In specific implementation, the preset temperature value may include a preset maximum temperature value and a preset minimum temperature value, when charging is started, the battery pack 50 is charged according to a preset current value, the temperature sampling circuit 70 collects the temperature of the battery pack 50, and when the temperature of the battery pack 50 exceeds the preset maximum temperature value, the current adjusting module 60 reduces the charging current to reduce the temperature of the battery pack 50, so as to prevent damage to the battery pack 50 due to abnormal circuit or over-high temperature of the battery pack 50; when the temperature of the battery pack 50 is lower than the preset minimum temperature value, the current regulation module 60 increases the charging current to improve the charging efficiency of the battery.

In one embodiment, as shown in fig. 7, the temperature sampling circuit 70 includes a temperature probe 701, a twenty-first resistor R21, a twenty-second resistor R22, a sixth capacitor C6, a third diode D3, and a fourth diode D4; the temperature probe 701 is connected with the battery pack 50 and used for acquiring the temperature of the battery pack 50; the second interface of the temperature probe 701 is grounded, the first interface of the temperature probe 701 is connected with one end of the twenty-first resistor R21, the other end of the twenty-first resistor R21 is connected with a fourth power supply, and the sixth capacitor C6 is connected in parallel between the first interface and the second interface of the probe; a cathode of the third diode D3 is connected to the other end of the twenty-first resistor R21, an anode of the third diode D3 is connected to a cathode of the fourth diode D4, and an anode of the fourth diode D4 is connected to the second interface of the temperature probe 701; one end of the twenty-second resistor R22 is connected between the twenty-first resistor R21 and the sixth capacitor C6, the other end of the twenty-second resistor R22 is connected between the third diode D3 and the fourth diode D4, and the other end of the twenty-second resistor R22 is connected to the current adjusting module 60. In a specific implementation, the fourth power supply may be 3.3V.

It should be understood that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same, and those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some technical features; and all such modifications and alterations are intended to fall within the scope of the appended claims.

Claims

1. An active equalizing charge system for a solar cell array, comprising:

a battery pack connected to an external power source to form a charging circuit, the battery pack including a plurality of strings of batteries connected in series;

the voltage acquisition modules are connected with the batteries in a one-to-one correspondence manner and used for acquiring the voltage of each string of batteries in the battery pack;

the charging protection module is connected between two adjacent batteries in series, each string of batteries is provided with one charging protection module, and the charging protection module is used for switching on or switching off the charging circuit;

the switch module is connected in parallel with the battery and the charging protection module, each string of batteries is provided with one switch module, and the switch modules are used for providing a path when the charging circuit is disconnected;

the control module is connected with the voltage acquisition module, the charging protection module and the switch module and is used for controlling the charging protection module and the switch module to be switched on or switched off according to the acquired voltage of each string of batteries;

when the voltage of one battery is higher than a preset equalizing starting voltage and the voltage difference between the battery and the battery with the lowest voltage in the battery pack is higher than a preset voltage difference, the charging protection module corresponding to the battery is controlled to be disconnected and the switch module is controlled to be switched on to equalize charging, wherein the preset equalizing starting voltage can be dynamically adjusted.

2. The active equalizing charge system of claim 1, wherein the preset equalizing start voltage is adjusted to decrease or increase according to a voltage difference between the battery and a battery with a lowest voltage in the battery pack.

3. The active equalizing charge system of claim 1, wherein the preset equalizing start voltage is adjusted to decrease or increase according to a voltage difference between a total voltage of all the cells in the battery pack and a preset total voltage.

4. The active equalizing charge system of claim 2 or 3, wherein the battery pack is charged in a charging mode with maximum power, wherein the power of the charging mode comprises: charging power at the time of equalizing charging, constant voltage charging power, and constant current charging power.

5. The active equalizing charge system of claim 4, wherein the charge protection module comprises a charge protection chip and a first MOS transistor, the first MOS transistor is connected to the battery, and the first MOS transistor is further connected to the charge protection chip and the control module respectively; the charging protection chip is used for detecting the voltage of the battery and outputting high and low levels according to the voltage of the battery so as to control the on-off of the first MOS tube.

6. The active equalizing charge system of claim 5, wherein the charge protection module further comprises a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a first transistor, and a second transistor; the battery is connected between the charging protection chip and the first MOS tube; an emitting electrode of the first triode is connected between the battery and a drain electrode of the first MOS tube, a collector electrode of the first triode is connected with one end of the thirteenth resistor, and the other end of the thirteenth resistor is connected with the charging protection chip; a base electrode of the first triode is connected with one end of the fourteenth resistor, and the other end of the fourteenth resistor is connected with the control module; one end of the fifteenth resistor is connected between the first triode and the fourteenth resistor, and the other end of the fifteenth resistor is connected with the emitter of the first triode and the drain of the first MOS tube; the source electrode of the first MOS tube is grounded, the grid electrode of the first MOS tube is connected with one end of the seventeenth resistor, the other end of the seventeenth resistor is connected with one end of the sixteenth resistor, and the other end of the sixteenth resistor is connected with the charging protection chip; a collector of the second triode is connected between the sixteenth resistor and the seventeenth resistor, and an emitter of the second diode is connected with a source of the first MOS tube; one end of the eighteenth resistor is connected between the first MOS tube and the second diode, and the other end of the eighteenth resistor is connected with the base electrode of the second diode; one end of the nineteenth resistor is connected between the base electrode of the second diode and the eighteenth resistor, and the other end of the nineteenth resistor is connected to the control module; one end of the twentieth resistor is connected with the charging protection chip, and the other end of the twentieth resistor is grounded.

7. The active equalizing charge system of claim 6, wherein the switch module comprises a second MOS transistor and a third resistor, a gate of the second MOS transistor is connected to one end of the third resistor, the other end of the third resistor is connected to the control module, and a source of the second MOS transistor is connected to a source of the first MOS transistor; the drain electrode of the second MOS tube is connected with the battery; the switch module further comprises a third MOS tube, the grid electrode of the third MOS tube is connected between the grid electrode of the second MOS tube and the third resistor, the source electrode of the third MOS tube is connected with the source electrode of the second MOS tube, and the drain electrode of the third MOS tube is connected with the drain electrode of the second MOS tube.

8. The active equalizing charge system of claim 4, further comprising a current adjusting module connected between the battery pack and the external power source, wherein the current adjusting module is configured to collect a charging current of the battery pack and increase or decrease the charging current according to a comparison result between the collected charging current and a preset current value of the current adjusting module, so as to keep the charging current stable.

9. The active equalizing charge system of claim 8, wherein the current regulating module comprises a DC-DC circuit, a current sampling circuit, an operational amplifier circuit, and a control unit; the DC-DC circuit is connected between the external power supply and the battery pack, the control unit is connected between the DC-DC circuit and the operational amplifier circuit, and the current sampling circuit is connected between the operational amplifier circuit and the battery pack.

10. The active equalizing charge system of claim 8, further comprising a temperature sampling circuit connected between the battery and the current regulation module, wherein the temperature sampling circuit is configured to collect a temperature of the battery pack and output a temperature collection result to the current regulation module, and the current regulation module regulates the charging current according to a comparison result between the temperature collection result and a preset temperature value of the current regulation module.