CN219181230U - Balanced charging circuit topology structure of lithium battery pack - Google Patents
Balanced charging circuit topology structure of lithium battery pack Download PDFInfo
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- CN219181230U CN219181230U CN202320138092.4U CN202320138092U CN219181230U CN 219181230 U CN219181230 U CN 219181230U CN 202320138092 U CN202320138092 U CN 202320138092U CN 219181230 U CN219181230 U CN 219181230U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E60/10—Energy storage using batteries
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Abstract
The utility model discloses an equalizing charge circuit topology structure of a lithium battery pack, which is characterized in that each battery in the lithium battery pack is connected into a charge-discharge circuit in turn, the voltage of each battery is detected, and the equalizing charge-discharge control of the lithium battery pack is realized by transferring the electric energy between the battery and a capacitor in the charge-discharge circuit. The utility model realizes the voltage balance of the battery pack by controlling the on logic of the switching tube based on the switching power supply step-up and step-down topology, has the characteristics of small volume, high efficiency, high working frequency, strong reliability and the like, and effectively solves the problems of poor reliability and short service life of the lithium battery pack caused by poor consistency of unit cells.
Description
Technical Field
The utility model relates to the technical field of battery charging and discharging, in particular to an equalizing charge circuit topological structure of a lithium battery pack.
Background
Two working modes of charging and discharging the lithium battery component; because of the production process, the capacities of the single rechargeable batteries in the lithium battery pack are always different, when the lithium battery pack is charged, the single battery with small battery capacity is fully charged first, but the single battery with large battery capacity is not fully charged, if the lithium battery pack is charged again, the single battery with small battery capacity can cause battery damage due to overcharging, the phenomenon of expansion and explosion caused by overheat of the single lithium battery can be caused, and if the lithium battery pack is not charged again, the single battery with large battery capacity is not fully charged, so that the use efficiency of the lithium battery pack is low; when the battery pack discharges, the single battery with small battery capacity is discharged firstly, but the single battery with large battery capacity is not discharged, at the moment, if the discharging is carried out again, the single battery with small battery capacity can damage the battery because of overdischarge, if the discharging is not carried out any more, the using capacity of the battery pack is lowered, the phenomenon of reversed polarity is easy to generate when the single battery energy is exhausted, the speed of reducing the single battery capacity of the lithium battery is accelerated for a long time, the capacity of the whole lithium battery pack is reduced, and the using efficiency of the battery pack is lowered.
Disclosure of Invention
In order to solve the defects of the technology, the utility model provides an equalizing charge circuit topological structure of a lithium battery pack.
In order to solve the technical problems, the utility model adopts the following technical scheme:
the equalizing charge circuit topological structure of the lithium battery pack comprises the lithium battery pack formed by connecting a plurality of batteries in series;
the positive electrode of each battery in the lithium battery pack is connected to the same node through one path of lead, each path of lead is provided with a positive electrode switch, and the node is connected with a first pin of a bridge type switch circuit;
the negative electrode of each battery in the lithium battery pack is connected to the same node through one path of lead, each path of lead is provided with a negative electrode switch, and the node is connected with a second pin of the bridge type switch circuit;
the third pin and the fourth pin of the bridge type switching circuit are correspondingly connected to two ends of the charge-discharge circuit.
Further, the bridge type switching circuit comprises a first switch, a second switch, a third switch and a fourth switch which are connected end to end, wherein the first pin is positioned between the first switch and the third switch, the second pin is positioned between the second switch and the fourth switch, the third pin is positioned between the first switch and the second switch, and the fourth pin is positioned between the third switch and the fourth switch.
Further, the charge-discharge circuit comprises an inductor, a capacitor and a charge-discharge switch, the inductor and the capacitor form a series branch, and the charge-discharge switch is connected with the series branch in parallel.
Further, one end of the capacitor is grounded through the grounding switch, and the other end of the capacitor is connected with a first analog-to-digital conversion chip for detecting the voltage of each battery.
Further, a third pin of the bridge switch circuit is connected to a node between the charge-discharge switch and the inductor through a wire, and a fourth pin of the bridge switch circuit is connected to a node between the charge-discharge switch and the capacitor through a wire.
Further, the positive electrode of the lithium battery pack is connected with a second analog-to-digital conversion chip for detecting the charging state of the battery pack through a resistor.
The utility model discloses an equalizing charge circuit topology structure of a lithium battery pack, which is based on a switching power supply buck-boost topology, realizes the voltage equalization of the battery pack by controlling the on logic of a switching tube, has the characteristics of small volume, high efficiency, high working frequency, strong reliability and the like, and effectively solves the problems of poor reliability and short service life of the lithium battery pack caused by poor consistency of unit cells.
Drawings
Fig. 1 is a schematic diagram of an equalizing charge circuit according to the present utility model.
Fig. 2 is a schematic diagram of the battery # 3 energy transfer to capacitor.
Fig. 3 is a schematic diagram of the energy transfer from the capacitor to the #2 cell.
Fig. 4 is a diagram of the battery charge.
Fig. 5 is a graph of the energy transfer simulation results for cell # 3 to capacitor.
Fig. 6 is a graph of the energy transfer simulation results of the capacitor to #2 cell.
Detailed Description
The utility model will be described in further detail with reference to the drawings and the detailed description.
The equalizing charge circuit topology structure of the lithium battery pack shown in fig. 1 comprises a lithium battery pack formed by serially connecting twelve batteries # 1 to # 12; the positive end of the first battery and the negative end of the twelfth battery are respectively provided with a contact point which is used as a positive electrode BAT+ and a negative electrode BAT-of the lithium battery pack, the positive electrode of the lithium battery pack is connected with a second analog-digital conversion chip B for detecting the charging state of the battery pack through a resistor R1, and meanwhile, the positive electrode of the lithium battery pack is connected with a switch K0 for controlling the conduction of a charging loop.
The positive electrode of each battery in the lithium battery pack is connected to the same node through one path of lead, each path of lead is provided with a positive electrode switch K1, K3...K9 and K11, and the node is connected with a first pin A of a bridge type switch circuit;
the negative electrode of each battery in the lithium battery pack is connected to the same node through one path of lead, each path of lead is provided with a negative electrode switch K2, K4...K10 and K12, and the node is connected with a second pin B of the bridge type switch circuit;
the third pin C and the fourth pin D of the bridge type switching circuit are correspondingly connected to two ends of the charge and discharge circuit.
The bridge switch circuit comprises a first switch KA, a second switch KB, a third switch KC and a fourth switch KD which are connected end to end, a first pin A is positioned between the first switch KA and the third switch KC, a second pin B is positioned between the second switch KB and the fourth switch KD, a third pin C is positioned between the first switch KA and the second switch KB, and a fourth pin D is positioned between the third switch KC and the fourth switch KD.
The charge-discharge circuit comprises an inductor L1, a capacitor C1 and a charge-discharge switch KX, wherein the inductor L1 and the capacitor C1 form a series branch, and the charge-discharge switch KX is connected with the series branch in parallel. One end of the capacitor C1 is grounded through the grounding switch KY, and the other end of the capacitor C1 is connected with the first analog-digital conversion chip A for detecting the voltage of each battery.
The third pin C of the bridge type switching circuit is connected to a node between the charge-discharge switch KY and the inductor L1 through a wire, and the fourth pin D of the bridge type switching circuit is connected to a node between the charge-discharge switch KY and the capacitor C1 through a wire.
In this embodiment, the switch K0 is normally turned on, and when the circuit is charged, current flows from the battery positive electrode bat+ through the #12 battery, through the switch K0, through the resistor R1, and to the battery negative electrode BAT-; at this time, if a positive voltage value is detected by the analog-to-digital conversion chip B, the circuit determines that the battery pack is in a charging state at this time. The K1-K12 switches are respectively connected with the positive electrode and the negative electrode of each battery, the control circuit controls the adjacent switches to be turned on in turn, the circuit only turns on one battery to the bus, and the voltage direction on the bus is different along with the different combinations of the switches, so that phase change is needed. At this time, the charge-discharge switch KX and the charge-discharge switch KY are opened, and the on-off conditions of the other switches KA to KD are changed along with the change of the access bus battery.
The following is exemplified by a 3# battery: when the 3# battery is connected to the bus, the current starts from the positive electrode of the 3# battery, reaches the positive electrode of the capacitor C1 through the positive electrode switch K3, the first change-over switch KA and the inductor L1, the negative electrode of the capacitor C1 returns to the negative electrode of the 3# battery through the fourth change-over switch KD and the negative electrode switch K4, and the capacitor C1 is charged by the 3# battery. After a certain time, the voltage of the capacitor C1 is equal to the voltage of the 3# battery, and at the moment, the positive electrode switch K3, the first change-over switch KA, the fourth change-over switch KD and the negative electrode switch K4 which are connected with the battery are disconnected. The charge-discharge switch KY is connected, and at the moment, voltage detection on the capacitor C1 can be carried out through the analog-to-digital conversion chip A, and the detected voltage is the voltage of the 3# battery just connected, so that the voltage of each battery in the battery pack is measured in turn through different switch combinations. When the charging voltage of the battery reaches more than 4V, balanced charge and discharge control is started, the battery energy with the highest measured voltage is transferred to the battery with the lowest voltage, at the moment, the switches K1-K12 are only turned on two batteries with energy transfer in turn, when the capacitor is connected with the high-voltage battery, the initial voltage on the capacitor C1 is very low, the battery voltage is higher, and the direct connection has relatively large loss, so that the circuit forms a forward energy transmission process by the forward energy transmission circuit shown in figure 2. The circuit is composed of a first change-over switch KA or a third change-over switch KC and a charge-discharge switch KX, wherein the first change-over switch KA or the third change-over switch KC is a main switch tube, the charge-discharge switch KX is a continuous tube, the charge is completed until the voltage on a capacitor C1 is equal to the voltage of a battery, at the moment, the energy in the capacitor is required to be transferred to the battery with low voltage, and the circuit is used for forming a reverse energy transmission circuit as shown in fig. 3 to carry out a reverse energy transmission process. The switches K1-Kn are connected with the battery with low voltage, the circuit is composed of a first switch KA or a third switch KC and a charge-discharge switch KX, the charge-discharge switch KX is a main switch tube, the first switch KA or the third switch KC is a freewheel tube, the voltage in the capacitor C1 is boosted and transferred to the low-voltage battery, when the voltage in the capacitor C1 is too low (usually < 2V), the capacitor is connected to the battery with high voltage for charging until the voltages of all the batteries are basically consistent, when the highest voltage battery voltage reaches 4.25V, the battery pack cannot be recharged, the switch K0 is disconnected, charge equalization is completed, the equalization circuit enters a waiting mode, and the circuit has to have small power consumption.
As shown in fig. 4, the actual voltage of 12 batteries at a certain time is the highest voltage of the battery No. 3 and the lowest voltage of the battery No. 2. According to the method described above, how the charge is transferred from the 3# battery to the 2# battery will now be described in detail, and the operation of the equalization circuit will be simulated. Assume that the 3# battery charge is 4.2V and the 2# battery charge is 3.8V. For ease of simulation, the battery is replaced with a 2000uF capacitor, and the capacitor C1 takes on 220uF (with an initial value of 2V).
First, forward energy transfer is performed, and the 3# battery transfers part of charge to the capacitor C1, and simulation diagrams are shown in fig. 2 and 5: the upper part is the voltage at two ends of the capacitor C1, the middle part is the voltage of the 3# battery, and the lower part is the current of the inductor L1. As can be seen from the figure, the voltage of capacitor C1 increases from 2V to 2.8715V, while the voltage of cell No. 3 decreases from 4.2V to 4.1122V.
Next, reverse energy transfer is performed, and the charge is transferred from the capacitor C1 to the No. 2 battery, as shown in fig. 3 and 6, wherein the upper part is the voltage of the No. 2 battery, the middle part is the voltage across the capacitor C1, and the lower part is the current of the inductor L1. As can be seen from the figure, the voltage of capacitor C1 was reduced from 2.3V to 2.0874V, while the voltage of cell No. 2 was increased from 3.8V to 3.8114V.
According to the simulation, when the electric quantity of the battery is unbalanced, the equalization circuit is adopted to transmit the electric quantity from the high-charge battery to the low-charge battery through forward and reverse energy transmission, so that the electric quantity equalization of the whole circuit is realized.
The above embodiments are not intended to limit the present utility model, and the present utility model is not limited to the above examples, but is also intended to be limited to the following claims.
Claims (6)
1. Equalizing charge circuit topological structure of lithium cell group, its characterized in that: the lithium battery pack is formed by connecting a plurality of batteries in series;
the positive electrode of each battery in the lithium battery pack is connected to the same node through one path of lead, each path of lead is provided with a positive electrode switch, and the node is connected with a first pin of a bridge type switch circuit;
the negative electrode of each battery in the lithium battery pack is connected to the same node through one path of lead, each path of lead is provided with a negative electrode switch, and the node is connected with a second pin of the bridge type switch circuit;
and the third pin and the fourth pin of the bridge type switching circuit are correspondingly connected to two ends of the charge-discharge circuit.
2. The equalizing charge circuit topology of a lithium battery pack of claim 1, wherein: the bridge type switching circuit comprises a first switch, a second switch, a third switch and a fourth switch which are connected end to end, wherein the first pin is positioned between the first switch and the third switch, the second pin is positioned between the second switch and the fourth switch, the third pin is positioned between the first switch and the second switch, and the fourth pin is positioned between the third switch and the fourth switch.
3. The equalizing charge circuit topology of a lithium battery pack of claim 1, wherein: the charge-discharge circuit comprises an inductor, a capacitor and a charge-discharge switch, wherein the inductor and the capacitor form a series branch, and the charge-discharge switch is connected with the series branch in parallel.
4. The equalizing charge circuit topology of a lithium battery pack of claim 3, wherein: one end of the capacitor is grounded through a grounding switch, and the other end of the capacitor is connected with a first analog-digital conversion chip for detecting the voltage of each battery.
5. The equalizing charge circuit topology of a lithium battery pack of claim 3, wherein: and a third pin of the bridge type switching circuit is connected to a node between the charge-discharge switch and the inductor through a wire, and a fourth pin of the bridge type switching circuit is connected to a node between the charge-discharge switch and the capacitor through a wire.
6. The equalizing charge circuit topology of a lithium battery pack of claim 3, wherein: the anode of the lithium battery pack is connected with a second analog-to-digital conversion chip for detecting the charging state of the battery pack through a resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320138092.4U CN219181230U (en) | 2023-02-07 | 2023-02-07 | Balanced charging circuit topology structure of lithium battery pack |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202320138092.4U CN219181230U (en) | 2023-02-07 | 2023-02-07 | Balanced charging circuit topology structure of lithium battery pack |
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- 2023-02-07 CN CN202320138092.4U patent/CN219181230U/en active Active
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