CN117639172A - Active balancing method and active balancing device for adaptive cell string number - Google Patents
Active balancing method and active balancing device for adaptive cell string number Download PDFInfo
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- CN117639172A CN117639172A CN202311636581.3A CN202311636581A CN117639172A CN 117639172 A CN117639172 A CN 117639172A CN 202311636581 A CN202311636581 A CN 202311636581A CN 117639172 A CN117639172 A CN 117639172A
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- 230000003044 adaptive effect Effects 0.000 title claims description 13
- 230000002457 bidirectional effect Effects 0.000 claims abstract description 38
- 238000001514 detection method Methods 0.000 claims description 36
- 238000006243 chemical reaction Methods 0.000 claims description 22
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- 239000013641 positive control Substances 0.000 description 5
- 238000007600 charging Methods 0.000 description 4
- 230000006978 adaptation Effects 0.000 description 3
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
- H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
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Abstract
The invention discloses an active equalization method and device for self-adapting cell string number, which is used for an active equalization circuit to perform equalization, wherein the active equalization circuit comprises a first gating unit, a second gating unit and a bidirectional DC/DC circuit, the first ends of the first gating unit and the second gating unit are connected with electric signals of each cell in a battery pack, the second end of the first gating unit is connected with the first end of the bidirectional DC/DC circuit, the second end of the bidirectional DC/DC circuit is connected with the second end of the second gating unit, the voltage of each cell is detected during active equalization, the first gating unit is controlled to conduct the electric signals of the corresponding cell, and the total electric signals between j strings of cells before the second gating unit is controlled to conduct; whether n electric cores in the battery pack are in a dropped state or not is detected through line sequence self-checking, if the electric core in the dropped state is a high-order electric core, the electric core in the previous position of the high-order electric core is marked as a j-th electric core, so that the string number of the battery pack is automatically adjusted, and the active balancing device is suitable for the battery packs with different string numbers and has wide adaptability.
Description
Technical Field
The present invention relates to the field of batteries, and more particularly to active equalization in battery packs.
Background
The battery generally performs line sequence detection before active equalization to judge whether the battery cells in the battery pack work normally, and when the battery cells fail, failure alarm is generally performed and the battery cells stop working.
In the prior art, the active equalization circuit is generally matched with the number of the battery cells in the battery pack, so that the self-adaptive serial number cannot be realized, the battery packs with different serial numbers often need to be selected from different active equalization circuits, the applicability is narrow, the serial number needs to be preset (for example, 12 strings need to be set) or the equalization cannot be continued when the serial number changes or even breaks, and the active equalization circuit is not intelligent and flexible enough, for example, in the use process, if a certain battery cell in the battery pack is disconnected, the active equalization module often stops working. Therefore, there is a strong need for an active equalization module that can automatically adapt to lithium batteries with different strings.
Disclosure of Invention
The invention aims to provide an active equalization method and an active equalization device for self-adaption of cell string numbers, which can be suitable for battery packs with different string numbers and have wide adaptability.
In order to achieve the above purpose, the invention discloses an active equalization method for self-adapting the number of battery strings, which is used for controlling an active equalization circuit to perform equalization, wherein the active equalization circuit comprises a first gating unit, a second gating unit and a bidirectional DC/DC circuit, the first ends of the first gating unit and the second gating unit are connected with the electric signal of each battery core in a battery pack, the second ends of the first gating unit are connected with the first end of the bidirectional DC/DC circuit, and the second ends of the bidirectional DC/DC circuit are connected with the second end of the second gating unit; the battery pack is provided with n electric cores which are sequentially connected in series, and the active equalization method comprises the following steps: when the equalization condition is met, the first gating unit is controlled to conduct the electric signal of the ith electric core needing equalization to the bidirectional DC/DC circuit; controlling the second gating unit to conduct the total electric signal between the 1 st to the j-th electric cores to the bidirectional DC/DC circuit; controlling the bidirectional DC/DC circuit to balance the total voltage formed by the series connection of the ith battery cell and the previous j battery cells; detecting whether the battery cells in the battery pack are in a dropped state, if the dropped battery cell sequence is positioned at the rear sides of all the on-line battery cells, controlling the second gating unit to switch the positive electrode electric signal of the power-on path from the dropped battery cell to the positive electrode electric signal of the battery cell with the highest sequence in the current on-line battery cells, wherein j is the serial number of the battery cell with the highest sequence in the current on-line battery cells.
Compared with the prior art, the invention is additionally provided with the second gating unit, and the serial numbers of the total voltage during the gating equalization can be used for leading the active equalization to be suitable for the battery packs with different serial numbers, and the adaptability is wide. Furthermore, when the high-order battery cell is in a power failure state, the invention can timely adjust the balanced battery string number and the total output line of the battery, exclude the high-order battery cell in the power failure state, and select the next high-order battery cell (the J-th battery cell) as the balanced positive electrode and the positive electrode of the total voltage of the battery pack, so that the battery pack can continue to work.
Preferably, when the active equalization circuit is powered on, the first gating unit is controlled to switch and conduct n electric cores in a time-sharing multiplexing mode, electric signals of the n electric cores are correspondingly collected through the voltage collecting circuit, and the indication unit is controlled to indicate abnormal conditions when any electric signal of the electric core is abnormal. So that the staff can find out faults in time.
Preferably, before the electric signals of n electric cores are correspondingly collected by the voltage collecting circuit, whether the electric signals of the electric cores are reversely connected is also judged, and if yes, the electric signals of the electric cores are subjected to polarity conversion. The scheme can adjust the polarity of the electric signal of the battery core in time when the electric signal of the battery core is reversely connected between the first gating units or between the first gating units and the line sequence detection module 41, and the subsequent detection control is not affected.
Preferably, a corresponding table of an active equalization current preset value and an equalization difference preset value is further provided, the equalization difference is the maximum difference of the battery pack, the active equalization current preset value is selected according to the interval where the difference of the battery pack is located when equalization is performed each time, PWM of the bidirectional DC/DC circuit is adjusted according to the active equalization current preset value to control the equalization current of active equalization, and the smaller the value of the interval where the difference of the battery pack is located is, the smaller the active equalization current preset value is. Through the adjustment of self-adaptive active balancing current, the consistency of the battery pack can be effectively balanced within a preset pressure difference, the occurrence of voltage rebound after the heavy current balancing is stopped is avoided, and the balancing effect is effectively improved.
Specifically, after each equalization, whether the equalized battery pack meets equalization conditions is also judged, if yes, secondary equalization is carried out, the preset value of the active equalization current is regulated according to the current pressure difference of the battery pack during secondary equalization, and equalization is stopped until the preset value of the active equalization current reaches a preset minimum equalization current value. The equalization is stopped by actively equalizing the magnitude of the preset value of the current, so that invalid equalization is effectively avoided, and the magnitude of the equalization is convenient to be adjusted by staff due to the adjustable preset value of the active equalization current.
Preferably, when the powered-off battery cells are arranged at the rear sides of all the online battery cells in sequence, the control indication unit indicates abnormal conditions and continues for a preset time, and after the preset time is exceeded, if the battery cells are still powered-off, the second gating unit is controlled to switch the positive electrical signals of the power-on battery cells with the powered-off channels to the positive electrical signals of the battery cells with the highest sequence in the current online battery cells. And the high-order disconnection of the battery cell caused by missed connection of operators is eliminated.
The invention also discloses an active equalization device with the self-adaptive cell string number, which comprises an active equalization circuit and a control module, wherein the active equalization circuit comprises a first gating unit, a second gating unit and a bidirectional DC/DC circuit, the first ends of the first gating unit and the second gating unit are connected with the two ends of each cell in the battery pack, the second ends of the first gating unit are connected with the first end of the bidirectional DC/DC circuit, and the second ends of the bidirectional DC/DC circuit are connected with the second end of the second gating unit; the battery pack has n cells connected in series in sequence, and the control module includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the active equalization method of cell string number adaptation as described above.
Preferably, the active equalization device further comprises an operation unit, a power supply unit and a rechargeable battery, the rechargeable battery supplies power to the power supply unit, the operation unit is operated to start the power supply unit, the power supply unit provides preset constant voltage power supply for each unit in the active equalization circuit, and a unidirectional DC/DC circuit is arranged between the second end of the second gating unit and the rechargeable battery so that the battery pack can charge the rechargeable battery.
Preferably, the active equalization device further comprises a line sequence detection module, the input end of the line sequence detection module is connected with the second end of the first gating unit, the first gating unit sequentially selects and conducts the electric signals of each electric core in a time-sharing multiplexing mode, so that the line sequence detection module sequentially obtains the electric signals of each electric core, the line sequence detection module converts the electric signals of the electric cores into corresponding detection signals and transmits the corresponding detection signals to the control module, and the control module judges whether the electric cores in the battery pack fall off according to the detection signals.
Specifically, the active equalization device further comprises a polarity conversion unit and a voltage acquisition unit, the line sequence detection module compares the positive electrode lead-out wire signal and the negative electrode lead-out wire signal of the battery cell, an effective positive connection signal is output when the positive electrode lead-out wire signal of the battery cell is larger than the negative electrode lead-out wire signal by a preset threshold value, an effective reverse connection signal is output when the negative electrode lead-out wire signal of the battery cell is larger than the positive electrode lead-out wire signal by a preset threshold value, and the detection signal comprises the effective positive connection signal and the effective reverse connection signal; the control module judges the wiring state of the battery cell according to the effective positive connection signal and the effective negative connection signal, outputs an effective positive connection control signal when the battery cell is positively connected, and outputs an effective negative connection control signal when the battery cell is negatively connected; the polarity conversion unit comprises a first switch conversion circuit and a second switch conversion circuit, wherein the first switch conversion circuit comprises a first switch driving circuit, a switch circuit A and a switch circuit B, and the second switch conversion circuit comprises a second switch driving circuit, a switch circuit C and a switch circuit D; the input end of the switch circuit A is connected with the positive electrode of the electric signal of the electric core which is currently gated by the first gating unit, the output end of the switch circuit A is connected with the positive electrode of the input end of the voltage acquisition unit, the control end of the switch circuit A is connected with the output end of the first switch switching circuit, the input end of the switch circuit B is connected with the negative electrode of the electric signal of the electric core which is currently gated by the first gating unit, the output end of the switch circuit B is connected with the negative electrode of the input end of the voltage acquisition unit, the control end of the switch circuit A is connected with the output end of the second switch switching circuit, and the input end of the first switch driving circuit is connected with the positive control signal and is connected with the switch circuit A and the switch circuit B when the positive control signal is effective; the input end of the switch circuit C is connected with the negative electrode of the electric signal of the electric core which is currently gated by the first gating unit, the output end of the switch circuit D is connected with the positive electrode of the electric signal of the electric core which is currently gated by the first gating unit, the output end of the switch circuit D is connected with the negative electrode of the electric signal of the electric core which is currently gated by the first gating unit, the input end of the second switch driving circuit is connected with the effective reverse connection signal, and the switch circuit C and the switch circuit D are conducted when the effective reverse connection control signal is generated; the voltage acquisition unit acquires the electric signals of the battery cell through the positive electrode of the input end and the negative electrode of the input end, acquires the voltage of the electric signals and transmits the acquired voltage to the control module.
Drawings
Fig. 1 is a block diagram of an active equalization apparatus with cell string number adaptation according to the present invention.
Fig. 2 is a schematic diagram of a line sequence detection module according to the present invention.
Fig. 3 is a structural diagram of the polarity conversion unit of the present invention.
Detailed Description
In order to describe the technical content, the constructional features, the achieved objects and effects of the present invention in detail, the following description is made in connection with the embodiments and the accompanying drawings.
Referring to fig. 1, the invention discloses an active equalization device 100 with self-adaptive cell string number, comprising an active equalization circuit and a control module 20, wherein the active equalization circuit comprises a first gating unit 11, a second gating unit 12 and a bidirectional DC/DC circuit 13, the first ends of the first gating unit 11 and the second gating unit 12 are connected with two ends of each cell in a battery pack, the second ends of the first gating unit 11 are connected with the first ends of the bidirectional DC/DC circuit 13, and the second ends of the bidirectional DC/DC circuit 13 are connected with the second ends of the second gating unit 12; the battery pack is provided with n electric cells which are sequentially connected in series.
The first gating unit 11 is a gating switching unit, and takes a plurality of MOS switches or miniature relay switches (including a mechanical relay and a photoelectric relay) SWAn as a core, and selects one of n battery CELL voltages through a time division multiplexing mode, and transmits the selected battery CELL voltage to the bidirectional DC/DC circuit 13 through the bus cell+ and CELL-, so as to be used as an input signal or an output signal of the bidirectional DC/DC circuit 13. The gate switch signals ENAn controlling the first gate units 11 are controlled by the control module 20 to gate n battery voltages one by one, respectively.
The second gating unit 12 is a gating switching unit, and uses a plurality of MOS switches or small relay switches (including a mechanical relay and a photoelectric relay) SWAn as a core, and selects, by a gating manner, total voltages corresponding to different string numbers of the battery pack to bus signals vin+, VIN-, as input signals or output signals of the bidirectional DC/DC circuit 13. The gating switch signals ENBn are controlled by the control module 20 to gate the total voltages between the 1 st string and the n th string of battery cells in a one-to-one correspondence mode.
Wherein the control module 20 comprises one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for performing an active balancing method for cell string number adaptation.
Specifically, the control module 20 uses the MCU and the embedded software as a core, and includes necessary peripheral devices such as a reference source, a crystal oscillator, a memory, a logic circuit, a buzzer, etc., and the basic hardware structure thereof belongs to a technology known in the industry, and will not be described again. The output current signal/input current signal IA of the bidirectional DC/DC circuit 13 is collected, and the PWM output of the duty ratio bidirectional DC/DC circuit 13 is adjusted after operation, so that the output current signal/input current signal IA current is a preset equalizing current threshold. The output signal SD of which can control the bidirectional DC/DC circuit 13 to select a discharge equalization or charge equalization mode.
Specifically, the active equalization method includes: during active equalization, the voltage of each cell is detected, when an equalization condition is met, for example, when the ith cell needs to be equalized, the first gating unit 11 is controlled to conduct electric signals at two ends of the ith cell Bi (an anode signal bi+ of a cell outgoing line and a cathode signal Bi-) of the cell outgoing line), the second gating unit 12 is controlled to conduct total electric signals B0-Bj between the 1 st to the j-th cells (the second gating unit 12 is controlled to conduct paths corresponding to the cell outgoing line B0 and the cell outgoing line Bj respectively), and the bidirectional DC/DC circuit 13 is controlled to conduct corresponding discharge equalization or charge equalization (discharge equalization is started when the electric quantity of the ith cell is excessive and charge equalization is started when the electric quantity of the ith cell is too small), so that equalization is conducted between the ith cell Bi and the total voltages B0-Bj formed by the 1 st to the j-th cells; and detecting whether n electric cores B1-Bn in the battery pack are in a dropped state or not through line sequence self-checking, if the arrangement position of the dropped electric cores in the battery pack is positioned at the rear side (high position) of all the electric cores currently in line, marking the electric cores arranged at the tail of the line in the electric cores as j-th electric cores, controlling the second gating unit 12 to switch the positive electric signals of the electric cores with the conducting paths in the dropped state into the positive electric signals of the electric cores with the highest sequence in the current electric cores (the second gating unit 12 conducts the electric core outgoing lines Bj), and adjusting the total electric signals B0-Bj (the self-adaptive serial number switching function) between the 1 st electric core and the new j-th electric core conducted by the second gating unit 12 in active equalization. For example, the current battery pack has 16 cells, if the 16 th cell is disconnected, the second gating unit 12 is controlled to conduct the total electrical signals B0-B15 between the negative electrode of the first cell (the conducting cell outgoing line B0) and the positive electrode of the 15 th cell (the conducting cell outgoing line B15), and the total electrical signals B0-B15 between the 1 st to 15 th cells are used as the balanced total voltage application, the power supply voltage output and the charging bus. j is equal to or greater than 1 and equal to or less than i, i=1, 2, 3 … n, n being an integer equal to or greater than 2.
The second gating unit 12 is used for conducting the total negative electrode and the total positive electrode of the battery (i.e. the battery bus of the battery) for discharging, charging and balancing the battery. In the present invention, the total negative electrode of the battery pack is the negative electrode of the fixed first cell B1, so that the lead-out line B0 of the total negative electrode of the battery pack (the lead-out line to which the negative electrode of the first cell B1 is connected) may be fixed to the second end of the bidirectional DC/DC circuit 13, or the lead-out line B0 of the total negative electrode of the battery pack may be connected to the second end of the bidirectional DC/DC circuit 13 through the second gating unit 12. The total positive electrode of the battery pack is a path selectable by the second gating unit 12, so the first end of the second gating unit 12 is respectively connected with the lead wires B1 … Bn of the positive electrodes of the 1 st to nth battery cells, so that the lead wires B1 … Bn are selectively conducted to the second end of the bidirectional DC/DC circuit 13, and the second gating unit 12 selects the positive electrode of the jth battery cell Bj (the conducted battery cell lead wire Bj) as the total positive electrode of the battery pack, that is, the positive bus.
The control module 20 controls the equalizing mode of the bidirectional DC/DC circuit 13 through the control signal SD.
The outgoing line of the total negative electrode of the battery pack is B0, the electrical signal output by the positive electrode transmission line of the ith electric core is Bi, so the battery pack is connected with the first gating unit 11 (the second gating unit 12) through n+1 electric core wires to be respectively connected with the electric core outgoing lines B0 and B1 … Bn, wherein the positive electrode signal bi+ of the electric core outgoing line output by the ith electric core corresponds to the electric core outgoing line Bi, the negative electrode signal bi+ of the electric core outgoing line corresponds to the electric core outgoing line B (i-1), for example, when the first gating unit 11 switches and outputs the electrical signals b1+ and B1-of the first electric core, the first gating unit 11 switches on the switches corresponding to the electric core outgoing line B1 and the electric core outgoing line B0. When two battery cell outgoing lines of a certain battery cell are reversely connected, the negative electrode signal Bi+ of the battery cell outgoing line is actually the positive electrode signal of the battery cell, and the positive electrode signal Bi+ of the battery cell outgoing line is actually the negative electrode signal of the battery cell.
Preferably, in the active equalization method, when the active equalization circuit is powered on, electrical signals of n electric cores in the battery pack are detected in real time through line sequence self-detection, and the control module 20 controls the indication unit 21 to indicate an abnormal condition when the electrical signal of any electric core is abnormal. Wherein the indication unit 21 is a display screen or an indication lamp. The control module 20 collects the electrical signals of the battery cells Bi gated by the first gating unit 11 through the voltage collecting unit 42.
Preferably, the positive electrode and the negative electrode of the electrical signal of the battery cell are detected, and if the positive electrode and the negative electrode of the battery cell are detected to be reversely connected, the electrical signal of the battery cell is subjected to polarity conversion when the electrical signal of the battery cell is reversely connected. The electrical signals of the gated battery cells are obtained through the line sequence detection module and are transmitted to the polarity conversion unit 43, the polarity of the electrical signals of the battery cells which are reversely connected are converted through the polarity conversion unit 43, negative electrode signals of the electrical signals of the battery cells are transmitted to the positive electrode input end of the voltage acquisition circuit, and positive electrode signals of the electrical signals of the battery cells are transmitted to the negative electrode input end of the voltage acquisition circuit.
Preferably, in the active equalization method, when active equalization is started, a corresponding table of an active equalization current preset value and an equalization difference preset value is preset in the control module, the equalization difference is the maximum difference of the battery pack, and when equalization is performed each time, the active equalization current preset value is selected according to the interval where the difference of the battery pack is located, PWM of the bidirectional DC/DC circuit is regulated according to the active equalization current preset value so as to control the equalization current of active equalization, and the smaller the value of the interval where the difference of the battery pack is located is, the smaller the active equalization current preset value is. Wherein the control module 20 delivers a control signal PWM to the bi-directional DC/DC circuit to control the actively balanced balancing current.
And after each equalization is finished, judging whether the equalized battery pack meets equalization conditions, if so, performing secondary equalization, and adjusting the preset value of the active equalization current according to the pressure difference of the current battery pack during secondary equalization until the preset value of the active equalization current reaches a preset minimum equalization current value, and stopping equalization.
When the voltage difference of the battery pack of the control module 20 is greater than or equal to a preset value, active equalization is started, and if not, active equalization is stopped. In this embodiment, active equalization is initiated when the stack differential pressure is, for example, 5mV or more. Of course, the preset value of the battery pack pressure difference comparison is not limited to the above-described values.
The control module 20 controls the first gating unit 11, the line sequence detecting module 41 and the voltage collecting unit 42 to perform line sequence self-checking in a certain period to determine whether each cell in the battery pack fails, whether the cell is disconnected, and whether the battery pack meets the balance condition. Wherein, automatic start line preface self-checking after power-on.
In this embodiment, the active equalization current preset value is configured and adjusted by the operation unit 301 and the indication unit 21. For example, in one embodiment, the active equalization current preset value takes the value of 1-10A and the equalization voltage difference preset value (e.g., 5 mV-1000 mV). In the equalization process, the magnitude of active equalization current can be adaptively adjusted according to the magnitude of the pressure difference of the battery pack, for example, the equalization current is 10A at the beginning, when the primary active equalization is stopped, if the equalization condition is judged to be met, the equalization can be started to be continued, and the current of the secondary equalization is automatically halved (rounded upwards), for example, 5A; and so on, the third active equalization current is 3A (2.5 is rounded up to 3); …, until the minimum equilibrium current value is 1A. Through the adjustment of self-adaptive active balancing current, the consistency of the battery pack can be effectively balanced within a preset pressure difference, the occurrence of voltage rebound after the heavy current balancing is stopped is avoided, and the balancing effect is effectively improved.
Preferably, when the powered-off battery cells are arranged at the rear sides of all the online battery cells in sequence, the control indication unit indicates abnormal conditions and continues for a preset time, and after the preset time is exceeded, if the battery cells are still powered-off, the second gating unit is controlled to switch the positive electrical signals of the power-on battery cells with the powered-off channels to the positive electrical signals of the battery cells with the highest sequence in the current online battery cells.
For example, in the active equalization process, when a high string of cells (cells arranged in the battery pack at positions on the rear side of all cells currently on line) is dropped, for example, the B16 position is dropped, a failure indication (for example, lasting 5 seconds) is first detected. And when the fault prompting time is still not treated, intelligent self-checking is automatically carried out, and the secondary low-serial battery channels B15 to VIN+ are sequentially switched to carry out active equalization, so that the self-adaptive serial number switching is realized. And so on.
When the adaptive string number switching function is not needed, the control module 20 may perform configuration fixed string number detection and equalization through the operation unit 301 and the indication unit 21. Or the second gating unit 12 is eliminated, VIN + is fixed to the highest voltage position of the n-string of cells, e.g. B16, and VIN-is fixed to the lowest voltage position of the n-string of cells, e.g. B0.
Preferably, the active equalization apparatus 100 further comprises an operation unit 301, a power supply unit 302 and a rechargeable battery 303, wherein the operation unit 301 is operated to activate the power supply unit 302, the power supply unit 302 provides a preset constant voltage power supply to each module in the active equalization circuit, a unidirectional DC/DC circuit 304 is provided between the second end of the second gating unit 12 and the rechargeable battery 303 so that the battery pack can charge the rechargeable battery 303, and the rechargeable battery 303 supplies power to the power supply unit 302. The unidirectional DC/DC circuit 304 is controlled by the control signal of the control module 20, and can step down the voltage vin+/VIN-, and then perform constant voltage and constant current charging on the rechargeable battery 303.
The rechargeable battery 303 is a built-in battery, and of course, the rechargeable battery 303 may be replaced by a non-rechargeable primary battery.
Preferably, the active equalization apparatus 100 further includes a USB charging unit 305, and the USB charging unit 305 transforms the voltage of the USB (typically 5V) and then charges the rechargeable battery 303 with constant voltage and constant current. The voltage supply range of the USB can reach 48V at maximum. The rechargeable battery 303 and the unidirectional DC/DC circuit 304 may exist simultaneously or separately.
The power supply unit 302 takes a BCUK circuit, an LDO circuit or a flyback circuit as a core, and provides a proper working voltage for the relevant units of the system. Preferably, the power supply unit 302 may be controlled to output by the operation unit 301, and also latched by the control module 20, so as to implement a system delay power-down function.
Wherein, the operation unit 301 is composed of m (m is greater than or equal to 1) keys, one of which is ON/OFF key for controlling the power supply unit 302 to be powered ON or powered OFF, and the other keys are used for realizing the functions of up, down, confirmation or deselection.
Referring to fig. 1, the active equalization apparatus 100 further includes a line sequence detection module 41, an input end of the line sequence detection module 41 is connected to a second end of the first gating unit 11, the first gating unit 11 sequentially selects and conducts voltages at two ends of each electric core in a time-division multiplexing manner, so that the line sequence detection module 41 sequentially obtains an electric signal of each electric core, the line sequence detection module 41 converts the electric signal of each electric core into detection signals V1 and V2 corresponding to high and low levels, the detection signals V1 and V2 are transmitted to the control module 20, and the control module 20 determines whether the electric core in the battery pack is disconnected, connected positively or not according to the detection signals V1 and V2.
The line sequence detecting module 41 compares the positive electrode lead-out signal bi+ and the negative electrode lead-out signal Bi-, outputs an effective positive connection signal when the positive electrode lead-out signal bi+ of the battery cell Bi is greater than the negative electrode lead-out signal Bi-by a preset threshold value, outputs an effective reverse connection signal when the negative electrode lead-out signal bi+ is greater than the positive electrode lead-out signal bi+ by a preset threshold value, and the detecting signals include an effective positive connection signal V1 and an effective reverse connection signal V2.
The control module 20 further determines the connection condition of the battery cell lead wires in the battery pack according to the detection signals V1 and V2 to output a corresponding positive connection control signal VS1 and a corresponding negative connection control signal VS2, wherein an effective positive connection control signal VS1 is output when the battery cell lead wires are connected positively, and an effective negative connection control signal VS2 is output when the battery cell lead wires are connected negatively.
Referring to fig. 2, the line sequence detecting module 41 includes a first comparing circuit and a second comparing circuit.
Referring to fig. 2, the first comparing circuit includes a first voltage dividing start circuit 311 and a positive switch circuit 321, the control end of the positive switch circuit 321 is connected to the output end of the first voltage dividing start circuit 311, the input end of the positive switch circuit 321 is connected to a constant voltage signal VDD, the output end of the positive switch circuit 321 outputs an effective positive signal V1, the first voltage dividing start circuit 311 divides the voltage difference between the positive signal bi+ and the negative signal Bi-into a first voltage dividing driving voltage and then sends the first voltage dividing driving voltage to the control end of the positive switch circuit 321, so that the positive switch circuit 321 conducts the positive switch circuit 321 when the first voltage dividing driving voltage is greater than the starting voltage of the positive switch circuit 321, so that the positive switch circuit 321 outputs the constant voltage signal VDD as the effective positive switch signal V1.
The first voltage division starting circuit 311 is composed of a plurality of resistors and a unidirectional conduction diode ZD1, and comprises a voltage division circuit formed by connecting a plurality of resistors in series between a positive electrode signal bi+ and a negative electrode signal Bi-, and the unidirectional conduction diode ZD1 connected in series with the voltage division circuit, wherein the unidirectional conduction diode ZD1 is conducted from the positive electrode signal bi+ to the negative electrode signal Bi-, and the first voltage division starting circuit 311 outputs the voltage difference between the positive electrode signal bi+ and the negative electrode signal Bi-to the positive connection switch circuit 321 in a voltage division manner according to the corresponding proportion. The forward switch 321 is composed of a plurality of switch transistors (e.g. MOS transistors, triode), resistors, unidirectional conduction diodes, and is driven to be conducted by corresponding high and low levels.
Referring to fig. 2, the second comparing circuit includes a second voltage dividing start circuit 312 and a reverse connection switch circuit 322, wherein a control end of the reverse connection switch circuit 322 is connected to an output end of the second voltage dividing start circuit 312, an input end of the reverse connection switch circuit 322 is connected to a constant voltage signal VDD, an output end of the reverse connection switch circuit 322 outputs an effective reverse connection signal V2, the second voltage dividing start circuit 312 divides a voltage difference between the negative electrode signal Bi-and the positive electrode signal bi+ into a second voltage dividing driving voltage and then transmits the second voltage dividing driving voltage to a control end of the reverse connection switch circuit 322, so that the reverse connection switch circuit 322 is turned on when the second voltage dividing driving voltage is greater than the starting voltage of the reverse connection switch circuit 322, and the output end of the reverse connection switch circuit 322 outputs the constant voltage signal VDD as the effective reverse connection signal V2.
The second voltage division starting circuit 312 is composed of a plurality of resistors and a unidirectional conduction diode ZD2, and comprises a voltage division circuit formed by connecting a plurality of resistors in series between a negative electrode signal Bi-and a positive electrode signal bi+ and the unidirectional conduction diode ZD2 connected in series with the voltage division circuit, wherein the unidirectional conduction diode ZD2 is conducted in the direction of the positive electrode signal bi+ by the negative electrode signal Bi-, and the second voltage division starting circuit 312 outputs the voltage difference between the negative electrode signal Bi-and the positive electrode signal bi+ to the reverse connection switch circuit 322 in a voltage division mode according to the corresponding proportion. The reverse connection switch circuit 322 is composed of a plurality of switch tubes (such as MOS tubes and triodes), resistors and unidirectional conduction diodes, and is driven to be conducted by corresponding high and low levels.
The control module 20 determines whether the battery cell is disconnected, over-voltage or reversely connected according to the detection signal V1 and the detection signal V2.
Referring to fig. 3, the active equalization apparatus 100 further includes a voltage acquisition unit 42 and a polarity conversion unit 43, where the polarity conversion unit 43 includes two switch conversion circuits with the same structure, one of the switch conversion circuits includes a switch driving circuit 431, a switch circuit a, and a switch circuit B, and the other switch conversion circuit includes a switch driving circuit 432, a switch circuit C, and a switch circuit D.
Referring to fig. 3, the control terminal of the switch driving circuit 431 is connected to the positive control signal VS1, the control terminal of the switch driving circuit 432 is connected to the negative control signal VS2, the positive control signal VS1 and the negative control signal VS2 are control signals with opposite high and low levels, and the control signals are output by the control module 20 according to whether the lead wires of the corresponding battery cells Bi are connected positively.
Referring to fig. 3, the input end of the switching circuit a is connected to the positive signal bi+ of the battery cell lead of the battery cell Bi currently being gated by the first gating unit 11, the output end of the switching circuit B is connected to the input end v0+ of the voltage acquisition unit 42, the input end of the switching circuit B is connected to the negative signal bi+ of the battery cell lead of the battery cell Bi currently being gated by the first gating unit 11, the output end of the switching driving circuit 431 is connected to the input end V0-of the voltage acquisition unit 42, when the battery cell Bi is being connected positively, the switching driving circuit 431 turns on the switching circuit a and the switching circuit B according to the effective positive control signal VS1, and when the battery cell Bi is being connected reversely or being disconnected, the switching driving circuit 431 cannot be connected positively to the control signal VS 1. The input end of the switch circuit C is connected with the negative electrode signal Bi+ of the battery cell outgoing line of the battery cell Bi which is currently gated by the first gating unit 11, the output end of the switch circuit D is connected with the input end V0+ of the voltage acquisition unit 42, the input end of the switch circuit D is connected with the positive electrode signal Bi+ of the battery cell outgoing line of the battery cell Bi which is currently gated by the first gating unit 11, the output end of the switch drive circuit 431 is connected with the switch circuit C and the switch circuit D when the battery cell Bi is reversely connected according to the effective reverse connection control signal VS2, and the switch drive circuit 431 is disconnected with the switch circuit C and the switch circuit D when the battery cell Bi is positively connected or is disconnected.
The input ends of the switch circuit A and the switch circuit B are respectively provided with a unidirectional conduction diode and are connected in parallel and then connected with the output end of the switch driving circuit 431. The input ends of the switch circuit C and the switch circuit D are respectively provided with a unidirectional conduction diode which are connected in parallel and then connected with the output end of the switch driving circuit 432.
The switch driving circuits 431 and 432 are voltage converting circuits, and the first switch driving circuit 431 and the second switch driving circuit 432 have the same structure and are composed of voltage dividing circuits connected in series between a control signal and ground. The switching circuits C and D consist of one or more switching tubes and some essential elements (resistors, diodes) as necessary. In this embodiment, the effective detection signal is a high level signal, and when the effective detection signal is a low level signal, the first switch driving circuit 431 and the second switch driving circuit 432 are composed of voltage dividing circuits connected in series between a constant high level and a control signal.
If the currently-gated cell Bi is being connected, the control module 20 controls VS1 to be high level, VS2 to be low level, and the switch driving circuit connected with VS1 drives the corresponding switch circuit to be turned on, and the switch driving circuit connected with VS2 drives the corresponding switch circuit to be turned off, so that Bi+ is conveyed to V0+ and Bi-is conveyed to V0-. If the currently-gated cell Bi is reversely connected, the control module 20 controls VS1 to be low level, VS2 to be high level, and the switch driving circuit connected with VS1 drives the corresponding switch circuit to be disconnected, and the switch driving circuit connected with VS2 drives the corresponding switch circuit to be conducted, so that Bi+ is conveyed to V0-, and Bi-is conveyed to V0+.
Of course, the setting of the high level and the low level of VS1 and VS2 is not limited to the above embodiment, and when the battery cell Bi is connected positively, VS1 may be controlled to be low level, VS2 to be high level, and the switch driving circuit connected with VS1 may drive the corresponding switch circuit to be turned on, and the switch driving circuit connected with VS2 may drive the corresponding switch circuit to be turned off; when the battery cell Bi is reversely connected, the control VS1 is high level, the control VS2 is low level, the corresponding switch circuit is driven to be disconnected by the switch driving circuit connected with the control VS1, and the corresponding switch circuit is driven to be conducted+ by the switch driving circuit connected with the control VS2.
Preferably, the line sequence detecting module 41 further has an overvoltage protection function, when the voltage difference generated by the reverse connection of the line sequence is larger, the detecting signals V1 and V2 sent to the control module 20 are invalid, and at this time, the VS1 and VS2 are invalid control signals, which are control signals for disconnecting the switch circuit a, the switch circuit B, the switch circuit C and the switch circuit D, so as to avoid the occurrence of damage caused by the excessive voltage collected by the voltage collecting unit 42. When a certain cell is disconnected, the control module 20 correspondingly outputs invalid control signals VS1 and VS2 to control the switch circuit a, the switch circuit B, the switch circuit C and the switch circuit D to be disconnected, and the voltage acquisition unit 42 does not acquire the voltage of the cell.
The foregoing description of the preferred embodiments of the present invention is not intended to limit the scope of the claims, which follow, as defined in the claims.
Claims (10)
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311636581.3A CN117639172B (en) | 2023-11-30 | 2023-11-30 | Active equalization method and active equalization device for self-adaption of cell string number |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311636581.3A CN117639172B (en) | 2023-11-30 | 2023-11-30 | Active equalization method and active equalization device for self-adaption of cell string number |
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| CN117639172B CN117639172B (en) | 2025-01-17 |
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| CN221507110U (en) * | 2023-11-30 | 2024-08-09 | 东莞市达锂电子有限公司 | Line sequence detection device of battery pack |
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| US20120086390A1 (en) * | 2009-01-30 | 2012-04-12 | Korea Advanced Institute Of Science And Technology | Charge Equalization Apparatus And Method For Series-Connected Battery String |
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| CN109980741A (en) * | 2019-04-10 | 2019-07-05 | 成都极空科技有限公司 | A kind of active equalization system of battery pack and its working method based on super capacitor |
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