The present disclosure relates to a battery cell balance circuit and a method of operating the same, and more particularly to an active battery cell balance circuit and a method of operating the same.
The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.
In the application of high-energy (high-power), high-voltage energy storage system, it is usually not operated by a single battery. In other words, in order to achieve high-energy (high-power) and high-voltage energy storage applications, the packaging of multiple battery cells will be modularized.
For a single battery cell 101-10N, when the battery cell 101-10N ages, abnormal phenomena such as easy to be fully charged and easy to discharge will occur. For the single battery module 100 shown in
An object of the present disclosure is to provide a battery cell balance circuit to solve the problems of existing technology.
In order to achieve the above-mentioned object, the battery cell balance circuit includes an AC/DC converter, a plurality of battery cells, a plurality of switches, an isolated DC/DC converter, a circuit switch, and a control unit. The AC/DC converter receives an AC power and convert the AC power into a DC power. The battery cells are connected in series to form a battery link. Each of the switches is correspondingly connected to each of the battery cells. An input side of the isolated DC/DC converter is coupled in parallel to an input side of each of the switches, and an output side of the isolated DC/DC converter is coupled to the battery link. The circuit switch is coupled between the AC/DC converter, the isolated DC/DC converter, and the plurality of switches. The control unit provides a plurality of control signals to correspondingly control the plurality of switches and the circuit switch.
Another object of the present disclosure is to provide a method of operating a battery cell balance circuit to solve the problems of existing technology.
In order to achieve the above-mentioned object, the battery cell balance circuit includes a plurality of battery cells connected in series to form a battery link, a plurality of switches, each of the switches correspondingly connected to each of the battery cells, and a circuit switch coupled between a DC power and the switches. The method includes steps of: controlling the switch corresponding to the battery cell to be turned on when a battery voltage of any one of the battery cells is detected to be greater than an upper threshold voltage, releasing electrical energy of the battery cell to the battery link, controlling the circuit switch to be turned on and controlling the switch corresponding to the battery cell to be turned on when the battery voltage of any one of the battery cells is detected to be less than a lower threshold voltage, and receiving, by the battery cell, the electrical energy from the DC power.
Accordingly, the battery voltage is adjusted through the release and supplement of electrical energy for the more seriously aged battery cells, that is, when the battery voltage of the battery cell is too high, the electrical energy is transmitted to the battery link, and when the battery voltage of the battery cell is too low, the electrical energy is supplemented by the AC power. Therefore, the battery voltage of the more severely aged battery cells during the charging and discharging processes can be maintained to be approximately the same as the battery voltage of other battery cells so as to ensure the normal operation of the overall battery module. Accordingly, in the application of the energy storage system, the operation of the battery module can be continuously maintained without requiring frequent replacement of battery cells. Until the annual repair, the seriously aged battery cells will be replaced in order to improve the economic benefits of the application of the energy storage system.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the present disclosure as claimed. Other advantages and features of the present disclosure will be apparent from the following description, drawings, and claims.
The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawing as follows:
Reference will now be made to the drawing figures to describe the present disclosure in detail. It will be understood that the drawing figures and exemplified embodiments of present disclosure are not limited to the details thereof.
Before describing the technical features of the battery cell balance circuit and the method of operating the same in detail, the passive battery cell balance technology and the active battery cell balance technology are briefly described. The passive battery cell balance technology refers to the energy consumption of battery cells with higher voltage through energy-consuming components. The common practice is: each battery cell is connected in parallel with resistance components through the switch circuit, and the energy of the battery cells with higher voltage is consumed by controlling the conduction (turned-on) of the switch and the parallel resistance components, thereby reducing the battery voltage of the battery cells to achieve a voltage balance between the battery cells.
In comparison with the passive battery cell balance technology, the active battery cell balance technology refers to the redistribution of energy between cells. For example, using energy storage components (such as inductors or capacitors) to temporarily store the energy of the battery cells with higher voltage, and then release the temporarily stored energy to the battery cells with lower voltage to achieve the effect of voltage balance between the battery cells.
However, in comparison with the existing active battery cell balance technology disclosed above, the present disclosure proposes different technical means to achieve the effect of active battery cell balance.
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Incidentally, the charging-discharging circuit 200 shown in
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Specifically, take the embodiment of
An input side of the isolated DC/DC converter 400 is coupled in parallel to an input side of each of the switches RL1-RL6. Specifically, the input side of the isolated DC/DC converter 400 has a positive end and a negative end, and the positive end is connected to a positive end of the DC power converted from the AC/DC converter 300 and the negative end is connected to a negative end of the DC power. Each electromagnetic relay has a first side and a second side, and the first side and the second side have a positive end and a negative end, respectively. The positive end of the first side is coupled to the positive end of the DC power and the positive end of the input side of the isolated DC/DC converter 400, the negative end of the first side is coupled to the negative end of the DC power and the negative end of the input side of the isolated DC/DC converter 400, and the positive end and the negative end of the second side are correspondingly connected to the positive ends and the negative ends of the battery cells, respectively. In other words, the positive ends of the first sides of all the electromagnetic relays are jointly coupled, and then coupled to the positive end of the DC power and the positive end of the input side of the isolated DC/DC converter 400. Similarly, the negative ends of the first sides of all the electromagnetic relays are jointly coupled, and then coupled to the negative end of the DC power and the negative end of the input side of the isolated DC/DC converter 400.
Moreover, an output side of the isolated DC/DC converter 400 is coupled in series to the battery link LCELL. The output side of the isolated DC/DC converter 400 has a positive end and a negative end, and the positive end is coupled to a positive end of the battery link LCELL (i.e., a positive end of the first battery cell Cell 1) and the negative end is coupled to a negative end of the battery link LCELL (i.e., a negative end of the sixth battery cell Cell 6) so that the output side of the isolated DC/DC converter 400 is coupled in series to the battery link LCELL.
The circuit switch Sc is coupled between the AC/DC converter 300 and the isolated DC/DC converter 400, that is, between the AC/DC converter 300 and the switch units RL1-RL6. In one embodiment, the circuit switch Sc may be, for example, but not limited to, an electromagnetic relay or a transistor switch, such as a MOSFET.
During the charging process of the plurality of battery cells Cell 1-Cell 6, if all battery cells Cell 1-Cell 6 are normal, the battery voltages of all battery cells Cell 1-Cell 6 will not be abnormally high when fully charged. Similarly, during the discharging process of the plurality of battery cells Cell 1-Cell 6, if all battery cells Cell 1-Cell 6 are normal, the battery voltages of all battery cells Cell 1-Cell 6 will not be abnormally low when fully discharged.
Once the battery voltage of any one of the battery cells Cell 1-Cell 6 is too high (abnormally high) during the charging process, the electrical energy of the battery cell with the too-high battery voltage is released to the battery link LCELL so that battery voltage of the battery cell is reduced and the battery cell is not over charged. In addition, once the battery voltage of any one of the battery cells Cell 1-Cell 6 is too low (abnormally low) during the discharging process, the AC power VAC provides electrical energy to the battery cell with the too-low battery voltage so that the battery voltage of the battery cell is increased and the battery cell is not over discharged.
Specifically, during the charging process of the battery cells Cell 1-Cell 6, when the control unit 500 detects that a battery voltage of any one of the battery cells Cell 1-Cell 6 is greater than the upper threshold voltage, the control unit 500 provides switch control signals SRL1-SRL6 to turn on the switch unit RL1-RL6 corresponding to the battery cell with the too-high battery voltage so that the electrical energy of the battery cell Cell 1-Cell 6 with the too-high battery voltage is released to the battery link LCELL through the isolated DC/DC converter 400. For example, when the control unit 500 detects that the battery voltage of the first battery cell Cell 1 is too high (i.e., the battery voltage is greater than the upper threshold voltage), the control unit 500 turns on the first switch unit RL1 by the first switch control signal SRL1 so that the electrical energy of the first battery cell is released to the battery link LCELL through the first switch unit RL1 and the isolated DC/DC converter 400. In addition to reducing the battery voltage of the first battery cell Cell 1 to prevent over-charging, the electrical energy of the first battery cell Cell 1 can also be used as the electrical energy for charging the battery link LCELL without wasting. Similarly, the operation principles of other battery cells are the same as those described above, and the detail description is omitted here for conciseness.
During the discharging process of the battery cells Cell 1-Cell 6, when the control unit 500 detects that a battery voltage of any one of the battery cells Cell 1-Cell 6 is less than the lower threshold voltage, the control unit 500 provides a switch control signal SCC to turn on the circuit switch Sc, and provides switch control signals SRL1-SRL6 to turn on the switch unit RL1-RL6 corresponding to the battery cell with the too-low battery voltage so that the battery cell Cell 1-Cell 6 with the too-low battery voltage receives electrical energy provided from the AC power VAC. In particular, the lower threshold voltage is less than the upper threshold voltage. For example, when the control unit 500 detects that the battery voltage of the first battery cell Cell 1 is too low (i.e., the battery voltage is less than the lower threshold voltage), the control unit 500 turns on the circuit switch Sc by the switch control signal SCC, and turns on the first switch unit RL1 by the first switch control signal SRL1 so that the AC power VAC supplies power to the first battery cell Cell 1 (i.e., provides the electrical energy to the first battery cell Cell 1) through the circuit switch Sc and the first switch unit RL1, thereby increasing the battery voltage of the first battery cell Cell 1 to prevent over-discharging. Similarly, the operation principles of other battery cells are the same as those described above, and the detail description is omitted here for conciseness.
Accordingly, the battery voltage is adjusted through the release and supplement of electrical energy for the more seriously aged battery cells, that is, when the battery voltage of the battery cell is too high, the electrical energy is transmitted to the battery link, and when the battery voltage of the battery cell is too low, the electrical energy is supplemented by the AC power. Therefore, the battery voltage of the more severely aged battery cells during the charging and discharging processes can be maintained to be approximately the same as the battery voltage of other battery cells so as to ensure the normal operation of the overall battery module. Accordingly, in the application of the energy storage system, the operation of the battery module can be continuously maintained without requiring frequent replacement of battery cells. Until the annual repair, the seriously aged battery cells will be replaced in order to improve the economic benefits of the application of the energy storage system.
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Specifically, during the charging process of the battery cells Cell 1-Cell 6, when the control unit 500 detects that a battery voltage of any one of the battery cells Cell 1-Cell 6 is greater than the upper threshold voltage, the control unit 500 provides switch control signals S1c-S7c to turn on the switch unit S1-S7 corresponding to the battery cell with the too-high battery voltage so that the electrical energy of the battery cell Cell 1-Cell 6 with the too-high battery voltage is released to the battery link LCELL through the isolated DC/DC converter 400. For example, when the control unit 500 detects that the battery voltage of the first battery cell Cell 1 is too high (i.e., the battery voltage is greater than the upper threshold voltage), the control unit 500 turns on the first switching switch unit Sa1 by the first switching switch control signal Sa1c, turns on the second switching switch unit Sa2 by the second switching switch control signals Sa2c, turns on the first switch unit S1 by the first switch control signal S1c, and turns on the second switch unit S2 by the second switch control signal S2c so that the electrical energy of the first battery cell is released to the battery link LCELL through the first switch unit S1, the second switch unit S2, the first switching switch unit Sa1, the second switching switch unit Sa2, and the isolated DC/DC converter 400. In addition to reducing the battery voltage of the first battery cell Cell 1 to prevent over-charging, the electrical energy of the first battery cell Cell 1 can also be used as the electrical energy for charging the battery link LCELL without wasting.
For example, when the control unit 500 detects that the battery voltage of the second battery cell Cell 2 is too high (i.e., the battery voltage is greater than the upper threshold voltage), the control unit 500 turns on the third switching switch unit Sb1 by the third switching switch control signal Sb1c, turns on the fourth switching switch unit Sb2 by the fourth switching switch control signals Sb2c, turns on the second switch unit S2 by the second switch control signal S2c, and turns on the third switch unit S3 by the third switch control signal S3c so that the electrical energy of the second battery cell is released to the battery link LCELL through the second switch unit S2, the third switch unit S3, the third switching switch unit Sb1, the fourth switching switch unit Sb2, and the isolated DC/DC converter 400. In addition to reducing the battery voltage of the second battery cell Cell 2 to prevent over-charging, the electrical energy of the second battery cell Cell 2 can also be used as the electrical energy for charging the battery link LCELL without wasting.
During the discharging process of the battery cells Cell 1-Cell 6, when the control unit 500 detects that a battery voltage of any one of the battery cells Cell 1-Cell 6 is less than the lower threshold voltage, the control unit 500 provides a switch control signal SCC to turn on the circuit switch Sc, and provides switch control signals S1c-S7c to turn on the switch unit S1-S7 corresponding to the battery cell with the too-low battery voltage so that the battery cell Cell 1-Cell 6 with the too-low battery voltage receives electrical energy provided from the AC power VAC. For example, when the control unit 500 detects that the battery voltage of the first battery cell Cell 1 is too low (i.e., the battery voltage is less than the lower threshold voltage), the control unit 500 turns on the circuit switch Sc by the switch control signal SCC, turns on the first switching switch unit Sa1 by the first switching switch control signal Sa1c, turns on the second switching switch unit Sa2 by the second switching switch control signal Sa2c, turns on the first switch unit S1 by the first switch control signal S1c, and turns on the second switch unit S2 by the second switch control signal S2c so that the AC power VAC supplies power to the first battery cell Cell 1 (i.e., provides the electrical energy to the first battery cell Cell 1) through the circuit switch SC, the first switching switch unit Sa1, the second switching switch unit Sa2, the first switch unit S1, and the second switch unit S2, thereby increasing the battery voltage of the first battery cell Cell 1 to prevent over-discharging.
For example, when the control unit 500 detects that the battery voltage of the second battery cell Cell 2 is too low (i.e., the battery voltage is less than the lower threshold voltage), the control unit 500 turns on the circuit switch SC by the switch control signal SCC, turns on the third switching switch unit Sb1 by the third switching switch control signal Sb1c, turns on the fourth switching switch unit Sb2 by the fourth switching switch control signal Sb2c, turns on the second switch unit S2 by the second switch control signal S2c, and turns on the third switch unit S3 by the third switch control signal S3c so that the AC power VAC supplies power to the second battery cell Cell 2 (i.e., provides the electrical energy to the second battery cell Cell 2) through the circuit switch SC, the third switching switch unit Sb1, the fourth switching switch unit Sb2, the second switch unit S2, and the third switch unit S3, thereby increasing the battery voltage of the second battery cell Cell 2 to prevent over-discharging.
Accordingly, the control principle of the switch assembly Sa (including switching switch units Sa1,Sa2,Sb1,Sb2) and the switch units S1-S7 of the battery cell balance circuit shown in
Similarly, the first embodiment of the switch unit shown in
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In summary, the advantages and features of the present disclosure are:
Although the present disclosure has been described with reference to the preferred embodiment thereof, it will be understood that the present disclosure is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the present disclosure as defined in the appended claims.
Number | Date | Country | Kind |
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202111579357.6 | Dec 2021 | CN | national |
This patent application claims the benefit of U.S. Provisional Patent Application No. 63/232,925, filed Aug. 13, 2021, which is incorporated by reference herein.
Number | Date | Country | |
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63232925 | Aug 2021 | US |