CN115706438A - Battery balancing circuit and operation method thereof - Google Patents
Battery balancing circuit and operation method thereof Download PDFInfo
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- CN115706438A CN115706438A CN202111579357.6A CN202111579357A CN115706438A CN 115706438 A CN115706438 A CN 115706438A CN 202111579357 A CN202111579357 A CN 202111579357A CN 115706438 A CN115706438 A CN 115706438A
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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
A battery balancing circuit comprises an alternating current-direct current converter, a plurality of battery cores, a plurality of switches, an isolated direct current-direct current converter, a line switch and a control unit. The ac-dc converter receives an ac power source. The battery cells are connected in series to form a battery chain. Each switch is connected to each battery cell. The isolated DC-DC converter is coupled to the switch and the battery chain in series. The line switch is coupled between the AC-DC converter and the isolated DC-DC converter and between the isolated DC-DC converter and the switch. The control unit provides a plurality of control signals to correspondingly control the switch and the line switch.
Description
Technical Field
The present invention relates to a battery balancing circuit and a method for operating the same, and more particularly, to an active battery balancing circuit and a method for operating the same.
Background
In high energy (high power) and high voltage energy storage system applications, a single battery is not usually operated, and therefore, in order to achieve high energy (high power) and high voltage energy storage applications, a plurality of battery cells (battery cells) are packaged and modularized. As shown in fig. 1, which is a perspective view of a battery module having a plurality of battery cells according to the related art, each battery module 100 has 18 battery cells 101 to 10N, which are arranged in two rows and connected in series. Therefore, in the application of the energy storage system, parallel connection can be provided by multiple sets of battery modules 100 at the same time, so as to achieve high-energy (high-power) and high-voltage power supply application.
For a single battery cell 101-10N, when the battery cell 101-10N ages, the battery cell is prone to be fully charged and discharged. For a single battery module 100 shown in fig. 1, which has 18 battery cells 101-10N, once one of the battery cells is aged in advance, the charging and discharging effects of the aged battery cell on the other 17 battery cells are as follows: during charging, the charging voltage of the battery cell with the serious aging increases rapidly, so that the battery cell with the serious aging may be overcharged (other battery cells may not be fully charged) or even damaged in the continuous normal charging process of the whole battery module 100. On the contrary, when discharging, the discharge voltage of the battery cell with the serious aging decreases rapidly, so that the battery module 100 may be overdischarged (other battery cells may not be discharged completely) or even damaged when the normal discharge process continues.
Therefore, how to design a battery balancing circuit and an operating method thereof to solve the problems and technical bottlenecks of the prior art is an important issue studied by the inventors of the present invention.
Disclosure of Invention
An objective of the present invention is to provide a battery balancing circuit, which solves the problems of the prior art.
To achieve the foregoing objective, the present invention provides a battery balancing circuit including an ac-dc converter, a plurality of battery cores, a plurality of switches, an isolated dc-dc converter, a line switch, and a control unit. The ac-dc converter receives an ac power source. A plurality of battery cells are connected in series to form a battery chain. Each switch is connected to each battery cell. The input side of the isolation type direct current-direct current converter is coupled with the input side of each switch in parallel, and the output side of the isolation type direct current-direct current converter is coupled with the battery chain in series. The line switch is coupled between the AC-DC converter and the isolated DC-DC converter, and the switches. The control unit provides a plurality of control signals to correspondingly control the switches and the line switches.
Another object of the present invention is to provide a method for operating a battery balancing circuit, which solves the problems of the prior art.
To achieve the above objects, the present invention provides a method for operating a battery balancing circuit, the battery balancing circuit comprising: a plurality of battery cells connected in series to form a battery chain; a plurality of switches, each switch being connected to each battery cell correspondingly; the line switch is coupled between the DC power source and the switches. The operation method comprises the following steps: in the charging process of the battery cells, when the battery voltage of any battery cell is detected to be higher than the upper critical voltage, the switch corresponding to the battery cell is controlled to be conducted; the electric energy of the battery core is released to the battery chain; in the discharging process of the battery cores, when the battery voltage of any battery core is detected to be lower than the lower critical voltage, the circuit switch is controlled to be conducted, and the switch corresponding to the battery core is controlled to be conducted; and the battery cell receives power from the direct current power source.
The battery voltage of the battery core with serious aging is adjusted through the release and supplement of energy through the proposed battery balancing circuit and the operation method of the battery balancing circuit, namely, when the voltage of the battery core rises faster in the charging process due to the reduction of the storage capacity, the energy of the battery core with higher voltage is transmitted to the battery chain, and when the voltage of the battery core drops faster in the discharging process due to the reduction of the storage capacity, the energy of the battery core with lower voltage is supplemented through the alternating current power supply, so that the normal operation of the battery core with serious aging in the whole battery module can be maintained, and the operation of the battery module can be continuously maintained in the condition of not frequently replacing the battery core in the application of the energy storage system. And replacing the battery core which is seriously aged until the time of annual repair so as to improve the economic benefit of the application of the energy storage system.
For a further understanding of the technology, means, and efficacy of the invention to be achieved, reference should be made to the following detailed description of the invention and accompanying drawings which are included to provide a further understanding of the invention, and to the purpose of providing a thorough and detailed understanding of the invention, and are incorporated in and constitute a part of this specification.
Drawings
FIG. 1: is a perspective view of a battery module having a plurality of battery cells according to the prior art;
FIG. 2 is a schematic diagram: a circuit block diagram of a first embodiment of a switch unit of the battery balancing circuit of the present invention;
FIG. 3: a circuit block diagram of a second embodiment of the switch unit of the battery balancing circuit of the present invention;
FIG. 4: a circuit block diagram of a third embodiment of the switch unit of the battery balancing circuit of the present invention;
FIG. 5: a block diagram of a preferred embodiment of the cell balancing circuit of the present invention;
FIG. 6: a detailed circuit block diagram of a preferred embodiment of the battery balancing circuit of the present invention;
FIG. 7 is a schematic view of: a flow chart of a method of operation of the battery balancing circuit of the present invention.
The reference numbers indicate:
100 battery module
101-10N of battery core
200 charge-discharge circuit
Cell 1-Cell m Cell core
S 1A -S mB Switch unit
S 1 -S m+1 Switch unit
Sa switch group
300 ac-dc converter
301 AC-DC converting circuit
400 isolation type DC-DC converter
500 control unit
501 Battery charging control Unit
502 controller
Cell 1-Cell 6 battery core
RL1-RL6 switch unit
S C Circuit switch
V AC AC power supply
L CELL Battery chain
SRL1-SRL6 switch control signal
S CC Switch control signal
S 1 -S 7 Switch unit
Sa1, sa2, sb1, sb2 switching unit
S1c-S7c switch control signal
Sa1c-Sb2c switch control signal
F1-F7 fuse
Detailed Description
The technical contents and detailed description of the present invention are described below with reference to the accompanying drawings.
Before the technical features of the battery balancing circuit and the operating method thereof of the present invention are explained in detail, a passive battery balancing technique and an active battery balancing technique will be briefly explained. The passive battery balancing technique means that energy of a battery core with higher voltage is consumed through an energy consumption assembly, and the common method is as follows: the battery cores are respectively connected with the resistor components in parallel through the switch circuit, and the energy of the battery core with higher voltage is consumed through the conduction of the control switch and the resistor components connected in parallel, so that the voltage of the battery core is reduced, and the balance of the voltage among the battery cores is achieved.
Compared to passive cell balancing, active cell balancing refers to redistributing energy between cells, such as: the energy of the battery core with higher voltage is temporarily stored by utilizing an energy storage component (such as an inductor or a capacitor), and then the temporarily stored energy is released to the battery core with lower voltage so as to achieve the effect of voltage balance of each battery core.
However, compared to the prior art, the present invention proposes a different technical means to achieve the active cell balancing function.
Please refer to the drawingsFig. 2 is a block diagram of a switching unit of a battery balancing circuit according to a first embodiment of the present invention. As shown in FIG. 2, the Cell balancing circuit has a plurality of (m) cells Cell 1-Celm, and the cells Cell 1-Celm are connected in series to form a Cell chain L CELL . In the configuration structure of the present embodiment, since the positive and negative poles (terminals) of each Cell 1-Cell m are respectively connected to a switch unit, that is, the positive and negative poles of the Cell 1 are respectively connected to the switch unit S 1A 、S 1B The positive and negative electrodes of the battery Cell Cell 2 are respectively connected with the switch unit S 2A 、S 2B And so on, the number of the switch units is twice as many as the number of the battery cells. Therefore, if the number of battery cells Cell 1 to Cell m is 18, the number of switch cells is 36. As shown in fig. 2, the cells Cell 1-Cell m pass through the switch unit S 1A -S mB Connected to the charge-discharge circuit 200, wherein the positive electrodes of the battery cells Cel 1-Celm pass through the switch unit S, respectively 1A -S mA Is connected to the positive power supply terminal or the positive power receiving terminal of the charge and discharge circuit 200. Similarly, the cathodes of the battery cells Cell 1-Cell m pass through the switch unit S respectively 1B -S mB Is connected to the negative power supply terminal or the negative power receiving terminal of the charge and discharge circuit 200.
Incidentally, the charge/discharge circuit 200 shown in fig. 2 is only a charge circuit and a discharge circuit that are operated when (at least one) of the battery cells Cell 1-Cell m needs to be charged when the voltage is too low or needs to be discharged when the voltage is too high. That is, the charging and discharging circuit 200 may be a circuit having both charging and discharging functions, or the charging and discharging circuit 200 may be two circuits with separate charging and discharging functions, but the invention is not limited thereto.
Fig. 3 is a circuit block diagram of a switch unit of a battery balancing circuit according to a second embodiment of the present invention. As shown in FIG. 3, the Cell balancing circuit has a plurality of (m) cells Cell 1-Celm, and the cells Cell 1-Celm are connected in series to form a Cell chain L CELL . In the configuration structure of the embodiment, since the positive electrode of the first Cell 1 is connected to a switch unit S 1 And the negative pole of the last Cell m is connectedIs connected with a switch unit S m+1 And the common connection end of the anode and the cathode of the middle Cell 2-Cell m-1 is connected with a switch unit S 2 -S m Furthermore, the charging and discharging operations of the battery cells Cell 1-Cell m are realized by the switch group Sa composed of 4 switch units (described in detail later), so that the total number of the switch units is the number of the battery cells plus 5. Therefore, if the number of the battery cells Cell 1 to Cell m is 18, the number of the switch cells is 23.
Fig. 4 is a circuit block diagram of a switch unit of a battery balancing circuit according to a third embodiment of the present invention. In contrast to the embodiments disclosed in the foregoing fig. 2 and 3, the switch unit shown in fig. 4 is implemented by the relays RL1-RL6 (by the battery chain L) CELL Take 6 battery cells as an example), in other words, by controlling the excitation of the relays RL1 to RL6, the on and off of the switches are realized, and a path for the charging and discharging operations of the battery cells Cell 1 to Cell 6 is provided.
Specifically, taking the embodiment of fig. 4 as an example, the battery balancing circuit of the present invention mainly includes an ac-dc converter 300, a plurality of battery cells Cell 1-Cell 6, a plurality of switch units RL1-RL6, an isolated dc-dc converter 400, and a line switch S C And a control unit 500. The AC-DC converter 300 receives an AC power supply V AC And converts an AC power supply V AC Is a direct current power supply. A plurality of battery cells Cell 1-Cell 6 are connected in series to form a battery chain L CELL . Each of the switch units RL1 to RL6 is connected to each of the cells Cell 1 to Cell 6. In the embodiment shown in fig. 4, each of the switching units RL1 to RL6 is an electromagnetic relay (relay), and the coil is excited by using the principle of electromagnetic effect, so that the contact changes the state, thereby realizing the switching function of on and off. The number of the switch units RL1 to RL6 is the same as that of the battery cells Cell 1 to Cell 6, that is, the first battery Cell 1 is connected with the first switch unit RL1, the second battery Cell 2 is connected with the second switch unit RL2 \8230, and so on.
As shown in fig. 4, the input side of the isolated dc-dc converter 400 is coupled to the first side of each of the switching units RL1 to RL6 in parallel, and as shown in fig. 4, the input side of the isolated dc-dc converter 400 has a positive electrode and a negative electrode, the positive electrode is connected to the positive electrode of the dc power converted by the ac-dc converter 300, and the negative electrode is connected to the negative electrode of the dc power converted by the ac-dc converter 300. Each electromagnetic relay has a first side and a second side, and has a positive electrode and a negative electrode, the positive electrode of the first side is coupled to the positive electrode of the dc power supply and the positive electrode of the input side of the isolated dc-dc converter 400, the negative electrode of the first side is coupled to the negative electrode of the dc power supply and the negative electrode of the input side of the isolated dc-dc converter 400, and the second side is coupled to the positive electrode and the negative electrode of the corresponding battery cell. In other words, the anodes of the first sides of all the magnetic relays are coupled together and then coupled together to the anode of the dc power source and the anode of the input side of the isolated dc-dc converter 400, and the cathodes of the first sides of the magnetic relays are coupled together and then coupled together to the cathode of the dc power source and the cathode of the input side of the isolated dc-dc converter 400.
Furthermore, the output side of the isolated dc-dc converter 400 is coupled in series with the battery chain L CELL As shown in fig. 4, the output side of the isolated dc-dc converter 400 has a positive electrode and a negative electrode, wherein the positive electrode is coupled to the battery chain L CELL Is connected to the positive terminal of the first Cell 1, and the negative terminal is connected to the battery chain L CELL Such that the output side of the isolated dc-dc converter 400 is coupled in series to the battery chain L (i.e., the negative terminal of the sixth battery Cell 6) CELL 。
Line switch S C The switch unit is coupled between the ac-dc converter 300 and the isolated dc-dc converter 400, and also between the ac-dc converter 300 and the switch units RL1-RL 6. Wherein the line switch S C May be an electromagnetic relay switch or a transistor switch (e.g., MOSFET), although neither is limiting.
In the charging process of the battery cells Cell 1-Cell 6, when all the battery cells Cell 1-Cell 6 are in the normal state, the battery voltage of all the battery cells Cell 1-Cell 6 will not be too high during the full charging. On the contrary, in the discharging process of the battery cells Cell 1-Cell 6, when all the battery cells Cell 1-Cell 6 are in the normal state, the battery voltage of all the battery cells Cell 1-Cell 6 will not be too low after discharging.
The Cell balancing circuit provided by the invention releases the electric energy of any Cell 1-Cell 6 to the battery chain L when the Cell voltage of the Cell 1-Cell 6 is overhigh in the charging process of the Cell 1-Cell 6 CELL The battery voltage of the battery cell is reduced so as not to cause overcharge. Furthermore, when the Cell voltage of any Cell 1-Cell 6 is too low during the discharge of the Cell cells 1-Cell 6, the AC power V is passed through AC The battery cell (with too low voltage) is provided with electric energy, so that the battery voltage of the battery cell is increased and the condition of over-discharge cannot occur.
Specifically, as shown in fig. 4, when the control unit 500 detects that the battery voltage of any one of the battery cells Cell 1-Cell 6 is higher than the upper threshold voltage during the charging process of the battery cells Cell 1-Cell 6, the control unit 500 controls the switching unit RL1-RL6 corresponding to the battery Cell with the excessively high voltage to be turned on by the switching control signal SRL1-SRL6 provided, so that the electric energy of the battery Cell RL1-RL6 with the excessively high voltage is released to the battery chain L through the isolated dc-dc converter 400 CELL . For example, in the battery chain L CELL In the charging process of the battery cells Cell 1-Cell 6, when the control unit 500 detects that the battery voltage of the first battery Cell 1 is too high (i.e. higher than the upper threshold voltage), the control unit 500 controls the first switch unit RL1 to be turned on by the first switch control signal SRL1, so that the electric energy of the first battery Cell 1 is released to the battery chain L through the first switch unit RL1 and the isolated dc-dc converter 400 CELL In addition to reducing the battery voltage of the first battery Cell 1 to prevent overcharge, the electric energy of the first battery Cell 1 can be used as the battery chain L CELL The charged electric energy is not wasted. Similarly, the operation principle of the other battery cells is the same as that described above, and therefore, the description thereof is omitted.
When the control unit 500 detects that the battery voltage of any Cell 1-Cell 6 is lower than the lower threshold voltage during the discharging process of the Cell cells 1-Cell 6, the control unit 500 provides the switch control signal S CC Control line switch S C Is conducted andand the switching units RL1-RL6 corresponding to the battery cells with the too low voltage are controlled to be conducted by the provided switching control signals SRL1-SRL6, so that the battery cells with the too low voltage are driven by the AC power supply V AC Electrical energy is received. Wherein the lower threshold voltage is less than the previously disclosed upper threshold voltage. For example, in the battery chain L CELL When the control unit 500 detects that the voltage of the first Cell 1 is too low (i.e. lower than the lower threshold voltage) during the discharging process of the cells Cell 1-Cell 6, the control unit 500 controls the switch control signal S CC Control line switch S C Is conducted, and the first switch unit RL1 is controlled to be conducted by the first switch control signal SRL1, so that the alternating current power supply V is conducted AC Via a line switch S C The first switch unit RL1 supplies electric power to the first Cell 1 to raise the Cell voltage of the first Cell 1 so as not to cause over-discharge. Similarly, the operation principle of other battery cells is the same as that described above, and will not be described herein.
Therefore, the battery voltage is adjusted by releasing and supplementing energy to the battery cell with serious aging through the battery balancing circuit, namely when the voltage of the battery cell rises faster in the charging process due to the reduction of the storage capacity of the battery cell, the energy of the battery cell with higher voltage is transmitted to the battery chain L CELL When the voltage of the battery core is reduced rapidly in the discharging process due to the reduction of the electric storage capacity, the battery core with lower voltage is supplemented with energy through the alternating current power supply, so that the voltage of the battery core with more serious aging can be maintained to be approximately the same as the voltage of other battery cores, the normal operation of the whole battery module is ensured, and the operation of the battery module can be continuously maintained under the condition that the battery core does not need to be replaced frequently in the application of an energy storage system. And replacing the battery core which is seriously aged until the time of annual repair so as to improve the economic benefit of the application of the energy storage system.
Referring to fig. 4, in the embodiment of the present invention, the Cell balancing circuit further includes an overcurrent protection component corresponding to the cells Cell 1-Cell 6, such as but not limited to fuses F1-F7. Therefore, when overcurrent abnormality occurs during the charging and discharging processes of the battery cells Cell 1-Cell 6, the corresponding fuses F1-F7 can provide overcurrent protection to protect the battery cells Cell 1-Cell 6.
Referring to fig. 5, a circuit block diagram of a preferred embodiment of a battery balancing circuit according to the present invention is shown, wherein fig. 5 is the embodiment of fig. 3 (i.e., a second embodiment of a switch unit) in combination with the aforementioned disclosure, the battery balancing circuit mainly includes an ac-dc converter 300, an isolated dc-dc converter 400, a control unit 500, and a plurality (6) of battery cells Cell 1-Cell 6 connected in series to form a battery chain L CELL A plurality of (7) switch units S 1 -S 7 And a switch group Sa including switching switch units Sa1, sa2, sb1, sb 2. Wherein the control unit 500 provides switch control signals S1c-S7c to control the switch unit S, respectively 1 -S 7 The changeover switch control signals Sa1c-Sb2c respectively control the switch units Sa1, sa2, sb1, sb2, and the switch control signal S CC Control circuit switch S C . In this embodiment, the switch unit S is turned on or off 1 -S 7 The configuration (connection relationship) design of (b) can greatly reduce the number of the switch units (as described in fig. 3) for the battery module with more battery cells, so that the paths for providing the charging and discharging operations of the battery cells Cell 1-Cell 6 can be realized in cooperation with the on and off of the switch units Sa1, sa2, sb1, sb 2.
Specifically, as shown in fig. 5, when the control unit 500 detects that the battery voltage of any one of the battery cells Cell 1-Cell 6 is higher than the upper threshold voltage during the charging process of the battery cells Cell 1-Cell 6, the control unit 500 controls the switch unit S corresponding to the battery Cell with the over-high voltage according to the provided switch control signals S1c-S7c 1 -S 7 The electric energy of the battery cells RL1-RL6 with the overhigh voltage is released to the battery chain L through the isolation type DC-DC converter 400 after being conducted CELL . For example, in the battery chain L CELL When the control unit 500 detects that the battery voltage of the first battery Cell 1 is too high (i.e. higher than the upper threshold voltage) during the charging process of the battery cells Cell 1 to Cell 6, the control unit 500 controls the first switch unit Sa1 to be turned on by the first switch control signal Sa1c, and controls the second switch unit S by the second switch control signal Sa2ca2 is turned on and the first switching unit S is controlled by the first switching control signal S1c 1 The second switch control signal S2c controls the second switch unit S when the first switch is turned on 2 Conducting to make the electric energy of the first Cell Cell 1 pass through the first switch unit S 1 A second switch unit S 2 The first and second switch units Sa1 and Sa2 and the isolated dc-dc converter 400 are released to the battery chain L CELL Besides, the voltage of the first Cell 1 is lowered to prevent overcharge, and the electric energy of the first Cell 1 can be used as the battery chain L CELL The charged electric energy.
In the same way, in the battery chain L CELL When the control unit 500 detects that the battery voltage of the second battery Cell 2 is too high during the charging process of the battery cells Cell 1-Cell 6, the control unit 500 controls the third switch unit Sb1 to be turned on by the third switch control signal Sb1c, controls the fourth switch unit Sb2 to be turned on by the fourth switch control signal Sb2c, and controls the second switch unit S to be turned on by the second switch control signal S2c 2 Conducting, third switch control signal S3c controls third switch unit S 3 Is turned on to allow the electric energy of the second Cell Cell 2 to pass through the second switch unit S 2 And a third switch unit S 3 The third switch unit Sb1, the fourth switch unit Sb2 and the isolated dc-dc converter 400 are released to the battery chain L CELL Besides, the battery voltage of the second battery Cell 2 is reduced so as not to cause overcharge, and the electric energy of the second battery Cell 2 can be used as the battery chain L CELL The charged electric energy.
When the control unit 500 detects that the battery voltage of any Cell 1-Cell 6 is lower than the lower threshold voltage during the discharging process of the cells Cell 1-Cell 6, the control unit 500 provides the switch control signal S CC Control circuit switch S C Is turned on and controls a switching unit S corresponding to the battery cell with an excessively low voltage by means of the supplied switching control signals S1c-S7c 1 -S 7 Is conducted so that the battery cell with an excessively low voltage is driven from the AC power supply V AC Electrical energy is received. For example, inBattery chain L CELL When the control unit 500 detects that the voltage of the first Cell 1 is too low (i.e. lower than the lower threshold voltage) during the discharging process of the cells Cell 1-Cell 6, the control unit 500 controls the switch control signal S CC Control line switch S C On, and controls the first switching unit Sa1 to be turned on by the first switching control signal Sa1c, the second switching unit Sa2 to be turned on by the second switching control signal Sa2c, and the first switching unit S by the first switching control signal S1c 1 Conducting, second switch control signal S2c controls second switch unit S 2 Is conducted to make the AC power supply V AC Via a line switch S C The first change-over switch unit Sa1, the second change-over switch unit Sa2 and the first switch unit S 1 And a second switching unit S 2 The first Cell 1 is supplied with electric energy to raise the Cell voltage of the first Cell 1 so as not to cause an over-discharge.
In a similar way, in the battery chain L CELL When the control unit 500 detects that the battery voltage of the second battery Cell 2 is too low during the discharging process of the battery cells Cell 1-Cell 6, the control unit 500 controls the signal S to be switched on and off CC Control line switch S C On, and the third switching unit Sb1 is controlled to be on by the third switching control signal Sb1c, the fourth switching unit Sb2 is controlled to be on by the fourth switching control signal Sb2c, and the second switching unit S is controlled to be on by the second switching control signal S2c 2 Conducting, third switch control signal S3c controls third switch unit S 3 Is conducted to make the AC power supply V AC Via a line switch S C A third selector switch unit Sb1, a fourth selector switch unit Sb2 and a second switch unit S 2 And a third switching unit S 3 The second Cell 2 is supplied with electric energy to raise the battery voltage of the second Cell 2 so as not to cause an over-discharge.
In summary, the switch group Sa (including the switch units Sa1, sa2, sb1, sb 2) and the switch unit S of the battery balancing circuit shown in fig. 5 1 -S 7 According to the control principle of AC-DC conversionThe positive and negative polarities of the dc power converted and output by the converter 300 correspond to the positive and negative polarities of the cells Cell 1-Cell 6 with too high (or too low) battery voltage, so as to adjust the battery voltage through releasing and supplementing energy for the severely aged cells.
Similarly, the first embodiment of the switch unit shown in fig. 2 can also be applied to the architecture of fig. 5, and the control principle of the switch unit is similar to that of fig. 5, so detailed control and operation descriptions are not repeated.
Fig. 6 is a detailed circuit block diagram of a battery balancing circuit according to a preferred embodiment of the invention. Fig. 6 more specifically discloses that the ac-dc converter 300 includes an ac-dc converting circuit 301 and a non-isolated dc-dc converting circuit (e.g., a buck converting circuit including a switch S1, a switch S2, an inductor L1, a capacitor C1 and a resistor R1). The control unit 500 includes a battery charging control unit 501 and a controller 502 to control the charging and discharging operations of the battery cells Cell 1-Cell 6. In addition, the battery balancing circuit further includes a controller area network CAN (including a controller area network integrated circuit CAN IC and a controller area network bus), so that the control unit 500 detects and controls the whole circuit, and transmits the result to the outside through the controller area network CAN, so that a remote operator CAN obtain monitoring and control, and CAN maintain the system in real time when the system is abnormal, so as to maintain the normal operation of the system.
Fig. 7 is a flowchart illustrating an operation method of the battery balancing circuit according to the present invention. The cell balancing circuit includes: a plurality of battery cells connected in series to form a battery chain; a plurality of switches, each switch being connected to each battery cell correspondingly; the line switch is coupled between the AC power source and the switches. The specific structure of the battery balancing circuit can be seen from the disclosure, and will not be described herein. The operation method of the battery balancing circuit of the invention comprises the following steps:
the cells may be charged (S11) and discharged (S21). During the charging process (S11) of the battery cells, when the battery voltage of any battery cell is detected to be higher than the upper critical voltage, the switch corresponding to the battery cell is controlled to be conducted (S12). Further, the electric energy of the battery cell is discharged to the battery chain (S13). During the discharging process of the battery cells (S21), when the battery voltage of any battery cell is detected to be lower than the lower critical voltage, the circuit switch is controlled to be conducted, and the switch corresponding to the battery cell is controlled to be conducted (S22). Further, the battery cell receives power from an alternating current power source (S23).
In summary, the present invention has the following features and advantages:
1. the cell balancing circuit according to the invention adjusts the cell voltage of a more aged cell by releasing and replenishing energy, i.e. when the voltage of the cell is too high, the energy is transferred to the cell chain L CELL When the voltage of the battery core is too low, the battery core is supplemented by the alternating current power supply, so that the voltage of the battery core with serious aging in the charging and discharging process is approximately the same as the voltage of other battery cores, the normal operation of the whole battery module is ensured, and the operation of the battery module can be continuously maintained under the condition that the battery core does not need to be frequently replaced in the application of the energy storage system. And replacing the battery core which is seriously aged until the time of annual repair so as to improve the economic benefit of the application of the energy storage system.
2. In selecting a specific battery module to couple to the battery balancing circuit through the solid-state switch, the switch can be connected in a manner of architecture by using the solid-state switch instead of a double-pole single-throw switch (a conventional solenoid switch), thereby increasing the service life of the switch in the battery balancing circuit and optimizing the voltage difference between the battery modules.
3. Charging a battery chain: and selecting the battery cell with the highest voltage, recovering the electric energy of the battery cell, feeding the electric energy back to the battery chain, and continuing the charging time of the battery chain.
4. Discharging a battery chain: and selecting the battery cell with the lowest voltage, and charging the battery cell by using the alternating current power supply to prolong the discharge time of the battery chain.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments of the invention, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (16)
1. A cell balancing circuit, comprising:
an AC-DC converter receiving an AC power and converting the AC power into a DC power;
a plurality of battery cells connected in series to form a battery chain;
a plurality of switches, each of which is connected to each of the battery cells;
the input side of the isolated DC-DC converter is coupled with the input side of each switch in parallel, and the output side of the isolated DC-DC converter is coupled with the battery chain in series;
a line switch coupled between the AC-DC converter and the isolated DC-DC converter and the plurality of switches; and
and the control unit provides a plurality of control signals to correspondingly control the plurality of switches and the line switch.
2. The battery balancing circuit according to claim 1, wherein when the control unit detects that the battery voltage of any battery cell is higher than the upper threshold voltage, the control unit controls the switch corresponding to the battery cell to be turned on, so that the electric energy of the battery cell is released to the battery chain through the isolated dc-dc converter.
3. The battery balancing circuit of claim 1, wherein when the control unit detects that the battery voltage of any battery cell is lower than a lower threshold voltage, the control unit controls the line switch to be turned on, and controls the switch corresponding to the battery cell to be turned on, so that the battery cell receives power from the ac power supply.
4. The battery balancing circuit of claim 1, wherein the plurality of switches are electromagnetic relays;
the first end of the positive pole of each switch is connected with the positive pole of the direct current power supply, and the first end of the negative pole of each switch is connected with the negative pole of the direct current power supply;
and the second end of the anode of each switch is correspondingly connected with the anode of the battery core, and the second end of the cathode of each switch is connected with the cathode of the battery core.
5. The battery balancing circuit of claim 1, wherein the plurality of switches includes a plurality of switch cells;
the positive electrode of each battery core is respectively connected with one end of one switch unit, and the other ends of the switch units are connected with the positive electrode of the direct-current power supply in a common way;
the negative electrode of each battery core is respectively connected with one end of one switch unit, and the other ends of the switch units are connected with the negative electrode of the direct current power supply in a common way.
6. The battery balancing circuit of claim 1, wherein the plurality of switches comprises a plurality of switch units and switch banks;
the positive electrode of the first battery cell is connected with one end of one switch unit, the negative electrode of the last battery cell is connected with one end of one switch unit, and the common connection ends of the positive electrode and the negative electrode of the centered battery cells are respectively connected with one end of one switch unit;
the switch group comprises a plurality of change-over switch units;
the other ends of the switch units are correspondingly connected with the switch units, so that the anodes of the battery cores are correspondingly connected with the anode of the direct current power supply, and the cathodes of the battery cores are correspondingly connected with the cathode of the direct current power supply.
7. The battery balancing circuit of claim 1, wherein the ac-dc converter includes an ac-dc conversion circuit and a non-isolated dc-dc conversion circuit.
8. The cell balancing circuit of claim 7, wherein the non-isolated dc-dc converter circuit is a buck converter circuit comprising two switches and an inductor.
9. The battery balancing circuit of claim 1, wherein the control unit includes a battery charging control unit and a controller to provide control of charging and discharging operations of the plurality of battery cells.
10. The cell balancing circuit of claim 1, further comprising:
and a plurality of overcurrent protection components correspondingly connected between the plurality of switches and the plurality of battery cells.
11. A method of operating a cell balancing circuit, the cell balancing circuit comprising: a plurality of battery cells connected in series to form a battery chain; a plurality of switches, each of which is connected to each of the battery cells; a line switch coupled between the DC power source and the switches; the operation method comprises the following steps:
in the charging process of the plurality of battery cells, when the battery voltage of any battery cell is detected to be higher than an upper critical voltage, the switch corresponding to the battery cell is controlled to be conducted;
the electric energy of the battery core is released to the battery chain;
in the discharging process of the plurality of battery cells, when the battery voltage of any battery cell is detected to be lower than a lower critical voltage, controlling the circuit switch to be conducted, and controlling the switch corresponding to the battery cell to be conducted; and
the battery cell receives power from the direct current power supply.
12. The method of operating a cell balancing circuit according to claim 11, wherein the cell balancing circuit further comprises:
the input side of the isolated DC-DC converter is coupled with the first side of each switch in parallel, and the output side of the isolated DC-DC converter is coupled with the battery chain in series;
and the electric energy of the battery core is released to the battery chain through the isolation type direct current-direct current converter.
13. The method of operating a cell balancing circuit of claim 11, wherein the cell balancing circuit further comprises:
an AC-DC converter receiving an AC power and converting the AC power into the DC power;
wherein the line switch is coupled to the AC power source through the AC-DC converter.
14. The method of operating a cell balancing circuit according to claim 11, wherein the plurality of switches are electromagnetic relays;
the first end of the positive pole of each switch is connected with the positive pole of the direct current power supply, and the first end of the negative pole of each switch is connected with the negative pole of the direct current power supply;
the second ends of the anodes of the switches are correspondingly connected with the anodes of the battery cores, and the second ends of the cathodes of the switches are connected with the cathodes of the battery cores.
15. The method of operating a battery balancing circuit of claim 11, wherein the plurality of switches includes a plurality of switch cells;
the positive electrode of each battery core is respectively connected with one end of one switch unit, and the other ends of the switch units are connected with the positive electrode of the direct-current power supply in a common way;
the negative electrode of each battery core is respectively connected with one end of one switch unit, and the other ends of the switch units are connected with the negative electrode of the direct current power supply in a common way.
16. The method of claim 11, wherein the plurality of switches comprises a plurality of switch units and switch sets;
the positive electrode of the first battery cell is connected with one end of one switch unit, the negative electrode of the last battery cell is connected with one end of one switch unit, and the common connection ends of the positive electrode and the negative electrode of the centered battery cells are respectively connected with one end of one switch unit;
the switch group comprises a plurality of change-over switch units;
the other ends of the switch units are correspondingly connected with the switch units, so that the anodes of the battery cores are correspondingly connected with the anode of the direct current power supply, and the cathodes of the battery cores are correspondingly connected with the cathode of the direct current power supply.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US17/751,414 US20230048191A1 (en) | 2021-08-13 | 2022-05-23 | Battery cell balance circuit and method of operating the same |
| JP2022084551A JP7427051B2 (en) | 2021-08-13 | 2022-05-24 | Battery balance circuit and its operating method |
| EP22175813.9A EP4135153B1 (en) | 2021-08-13 | 2022-05-27 | Battery cell balance circuit and method of operating the same |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US202163232925P | 2021-08-13 | 2021-08-13 | |
| US63/232,925 | 2021-08-13 |
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| CN115706438A true CN115706438A (en) | 2023-02-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111579357.6A Pending CN115706438A (en) | 2021-08-13 | 2021-12-22 | Battery balancing circuit and operation method thereof |
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| Country | Link |
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| CN (1) | CN115706438A (en) |
| TW (1) | TWI792793B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8294421B2 (en) * | 2008-09-05 | 2012-10-23 | O2Micro Inc | Cell balancing systems employing transformers |
| JP5567684B2 (en) * | 2009-12-14 | 2014-08-06 | リーチ インターナショナル コーポレイション | Battery balancing circuit and method for balancing energy stored in a plurality of cells of a battery having a first terminal and a second terminal |
| US9172259B2 (en) * | 2012-11-29 | 2015-10-27 | Samsung Sdi Co., Ltd. | Apparatus for managing battery, and energy storage system |
| TWI581543B (en) * | 2014-10-03 | 2017-05-01 | 輝創電子股份有限公司 | Active balancing module for a series battery and control method thereof |
| US10063070B2 (en) * | 2016-11-25 | 2018-08-28 | National Chung Shan Institute Of Science And Technology | Battery active balancing system |
| TWI666851B (en) * | 2018-05-04 | 2019-07-21 | 大陸商東莞市高效電控有限公司 | Optimized battery balance system and operation method thereof |
| US10615610B1 (en) * | 2019-05-28 | 2020-04-07 | Ekergy Llc | System and method for efficient charging of multiple battery cassettes |
| CN111976538B (en) * | 2019-12-27 | 2022-09-20 | 中北大学 | Equalizing structure and equalizing method of vehicle-mounted composite power supply system |
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| TWI792793B (en) | 2023-02-11 |
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