TWI788254B - Power supply system having battery packs connected in series - Google Patents

Abstract

A power supply system having battery packs connected in series is provided. A first terminal of a discharge transistor is connected to an anode of a first internal diode of the discharge transistor. A second terminal of the discharge transistor is connected to a cathode of the first internal diode. A first terminal of a charging transistor is connected to the second terminal of the discharge transistor and a cathode of a second internal diode of the charging transistor. A second terminal of the charging transistor is connected to an anode of the second internal diode and a positive terminal of a battery circuit. A positive input terminal of a bypass circuit is connected to the cathode of the first internal diode. A negative input terminal of the bypass circuit is connected to a negative terminal of the battery pack.

Description

Power supply system for battery packs in series

The invention relates to a battery pack, in particular to a power supply system for a battery pack connected in series.

An uninterruptible power system (Uninterruptible Power System, UPS) usually uses a series circuit of multiple battery packs. The increase in the number of battery packs connected in series increases the overall voltage of the system. Due to the different sources of different battery packs, the battery packs may have different voltages. For example, some battery packs may be fully charged, but other battery packs may not be fully charged. Furthermore, even if all battery packs are fully charged, these battery packs may have different voltages due to different material properties (such as lithium ternary/lithium iron) or the age of the battery.

When the voltages of multiple battery packs connected in series are different, during the charging process of multiple battery packs, some battery packs may reach the fully charged voltage first and cut off the charging circuit, so that other battery packs that are not fully charged Unable to continue charging, the voltage of some battery packs is not fully charged, resulting in insufficient capacity of the entire power supply system.

The technical problem to be solved by the present invention is to provide a power supply system for series-connected battery packs, which includes a power supply circuit and multiple battery packs. The power supply circuit is configured to supply charging current. Multiple battery packs are arranged in sequence and connected in series. Each battery pack includes a battery circuit, a discharge transistor, a charge transistor, a bypass circuit and a control circuit. A battery circuit consists of multiple batteries connected in series. The first end of the discharge transistor is connected to the anode of the first internal diode of the discharge transistor. The second end of the discharge transistor is connected to the cathode of the first internal diode. The first terminal of the charging transistor is connected to the second terminal of the discharging transistor and the cathode of the second internal diode of the charging transistor. The second terminal of the charging transistor is connected to the anode of the second internal diode and the positive terminal of the battery circuit. The positive input terminal of the bypass circuit is connected to the cathode of the first internal diode. The negative input terminal of the bypass circuit is connected to the negative terminal of the battery pack. The control circuit is connected to the control terminal of the discharge transistor, the control terminal of the charge transistor and the bypass circuit. The control circuit is configured to turn on the discharging transistor and the charging transistor but turn off the bypass circuit so that the charging current flows through the battery circuit instead of the bypass circuit when the battery circuit is not fully charged. The control circuit is configured to turn off the charging transistor but turn on the bypass circuit so that the charging current flows through the bypass circuit but not through the battery circuit when the battery circuit is fully charged. One of the battery packs is defined as the last battery pack. The output end of the bypass circuit of the last battery pack and the negative end of the battery circuit are connected to the input end of the power supply circuit, and the first end of the discharge transistor of the other battery pack is directly connected to the output end of the power supply circuit. For each battery group except the last battery group, the negative terminal of the battery circuit and the output terminal of the bypass circuit are connected to the first terminal of the discharge transistor of the next battery group and the anode of the first internal diode.

In one embodiment, the bypass circuit of each battery pack includes a voltage supply element, a transformer, a first switch element, a first diode, a second diode, and a second switch element. The transformer has a first side and a second side opposite the first side. The first end of the first side of the transformer is connected to the cathode of the first internal diode and the positive end of the voltage supply element. The first end of the first switching element is connected to the second end of the first side of the transformer. The second end of the first switch element is connected to the negative end of the voltage supply element. The control end of the first switch element is connected to the control circuit. The anode of the first diode is connected to the first end of the second side of the transformer. The anode of the second diode is connected to the cathode of the first diode. The cathode of the second diode is connected to the positive terminal of the battery circuit. The first end of the second switch element is connected to the anode of the second diode. The second end of the second switching element is connected to the second end of the second side of the transformer. The control end of the second switch element is connected to the control circuit. The second end of the first switch element and the second end of the second switch element of the last battery pack are connected to the input end of the power supply circuit. Inside each battery pack other than the last battery pack, the second end of the first switch element and the second end of the second switch element are connected to the first end of the discharge transistor of the next battery pack.

In one embodiment, the bypass circuit of each battery pack further includes a resistor, the first end of the resistor is connected to the cathode of the first diode, and the second end of the resistor is connected to the second end of the second side of the transformer.

In one embodiment, the first switching element is a transistor.

In one embodiment, the second switching element is a transistor.

In one embodiment, each battery pack further includes a detection circuit. The detection circuit is connected to the negative terminal of the control circuit and the battery circuit. The detection circuit is configured to detect the output/input current of the battery circuit, and the control circuit controls the discharge transistor, the charge transistor and the bypass circuit accordingly.

In one embodiment, each battery pack further includes a sensing resistor. The first end of the sensing resistor is connected to the negative end of the battery circuit and the detection circuit. The second end of the sensing resistor is connected to the detection circuit. The second terminal of the sensing resistor of the last battery pack is connected to the input terminal of the power supply circuit, and the second terminals of the sensing resistors of the other battery packs are connected to the first terminal of the discharge transistor of the next battery pack.

As mentioned above, the present invention provides a power supply system for battery packs connected in series. During the charging process of multiple battery packs connected in series, some of the battery packs will not be charged when they are fully charged. Other battery packs that have not been fully charged in series can still continue to charge, so that multiple battery packs in the final power supply system can be fully charged, so that the voltages of multiple battery packs are balanced/close to each other, so that the power supply system has sufficient capacity.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the provided drawings are only for reference and description, and are not intended to limit the present invention.

The implementation of the present invention is described below through specific specific examples, and those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various modifications and changes can be made to the details in this specification based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple illustration, and are not drawn according to the actual size, which is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention. In addition, the term "or" used herein may include any one or a combination of more of the associated listed items depending on the actual situation.

Please refer to Fig. 1 and Fig. 2, wherein Fig. 1 is a block diagram of the power supply system of the series battery pack of the embodiment of the present invention; Fig. 2 is the first circuit inside a battery pack of the power supply system of the series battery pack of the embodiment of the present invention Layout.

The power supply system in the embodiment of the present invention may include a plurality of battery packs PA1~PAn and a power supply circuit 10 as shown in FIG. The present invention is not limited thereto.

A plurality of battery packs PA1˜PAn are arranged in sequence and connected in series to form a battery circuit. The power supply circuit 10 can be connected to this battery circuit. The power supply circuit 10 can supply the charging current IS to the battery circuit to charge the battery packs PA1˜PAn.

In this embodiment, for example, each of the battery packs PA2 ˜ PAn may have the same configuration of circuit components as the battery pack PA1 , so the following description is only for the battery pack PA1 , and the same content will not be repeated.

As shown in FIG. 2 , the battery pack PA1 may include a battery circuit BST, a discharge transistor F1 , a charge transistor F2 and a control circuit 20 . The battery circuit BST of the battery pack PA1 may include a plurality of batteries BY1-BYn, wherein n is any appropriate integer value representing the number of batteries in the battery pack PA1, which may depend on actual needs, and the present invention is not limited thereto. In the battery pack PA1, a plurality of batteries BY1 to BYn are connected in series with each other.

The first terminal of the discharge transistor F1 can be connected to the anode of the first internal diode DT of the discharge transistor F1. The second terminal of the discharge transistor F1 can be connected to the cathode of the first internal diode DT and the first terminal of the charge transistor F2.

The first terminal of the charging transistor F2 can be connected to the cathode of the second internal diode CT of the charging transistor F2. The second terminal of the charging transistor F2 can be connected to the anode of the second internal diode CT and the positive terminal of the battery circuit BST (ie, the positive terminal of the battery BY1).

It should be noted that the battery pack PA1 may include a bypass circuit FL. The positive input terminal of the bypass circuit FL can be connected to the cathode of the first internal diode DT. The negative input terminal of the bypass circuit FL can be connected to the negative terminal of the battery pack PA1. The control circuit 20 can be connected to the control terminal of the discharge transistor F1 , the control terminal of the charge transistor F2 and the bypass circuit FL. The control circuit 20 can control the operation of the discharge transistor F1, the charge transistor F2 and the bypass circuit FL.

For example, the bypass circuit FL of the battery pack PA1 may include a flyback (Flyback) circuit, which may include a voltage source S1 as a voltage supply element (or practically replaced by a power supply circuit configured with multiple voltage supply elements), The transformer ST, the first switching element A1 , the first diode D1 , the second diode D2 , the second switching element B1 , and the resistor R are just examples here, and the present invention is not limited thereto.

The transformer ST has a first side and a second side opposite to the first side. The first end of the first side of the transformer ST can be connected to the cathode of the first internal diode DT and the positive end of the voltage source S1. The second end of the first side of the transformer ST may be connected to the first end of the first switching element A1. The second end of the first switching element A1 can be connected to the negative end of the voltage source S1. The control terminal of the first switching element A1 can be connected to the control circuit 20 . The first switching element A1 can be a transistor.

The anode of the first diode D1 can be connected to the first end of the second side of the transformer ST. The cathode of the first diode D1 can be connected to the anode of the second diode D2. The cathode of the second diode D2 can be connected to the positive terminal of the battery circuit BST (ie the positive terminal of the battery BY1).

The second switch element B1 can be a transistor. The first end of the second switching element B1 can be connected to the anode of the second diode D2. The second end of the second switching element B1 can be connected to the second end of the second side of the transformer ST, the negative end of the battery BYn of the battery circuit BST, and the second end of the first switching element A1. The control terminal of the second switch element B1 can be connected to the control circuit 20 . The first end of the resistor R can be connected to the cathode of the first diode D1. The second end of the resistor R can be connected to the second end of the second side of the transformer ST.

Please refer to Fig. 1 and Fig. 3, wherein Fig. 1 is the block diagram of the power supply system of the series battery pack of the embodiment of the present invention; Fig. 3 is the second circuit inside a battery pack of the power supply system of the series battery pack of the embodiment of the present invention Layout. The same content as above, will not be repeated here.

Each of the battery packs PA1˜PAn may further include a detection circuit 30 . The detection circuit 30 can be connected to the control circuit 20 and the negative terminal of the battery circuit BST (ie, the negative terminal of the battery BYn). The detection circuit 30 can detect the parameters of the battery circuit BST, such as the output/input current or voltage value of the battery circuit BST. The control circuit 20 can control the operation of the control terminal of the discharge transistor F1 , the control terminal of the charge transistor F2 and the bypass circuit FL according to the parameters detected by the detection circuit 30 .

If necessary, each of the battery packs PA1˜PAn may further include a sensing resistor Rs. The first end of the sensing resistor Rs can be connected to the negative end of the battery circuit BST and the detection circuit 30 . The second end of the sensing resistor Rs can be connected to the detection circuit 30 and the second end of the second switching element B1.

The detection circuit 30 can detect the current flowing through the sensing resistor Rs or detect the voltage at the first terminal of the sensing resistor Rs and the voltage at the second terminal of the sensing resistor Rs and calculate the voltage difference between them (ie, sensing The voltage of the resistor Rs) is used to control the control terminal of the discharge transistor F1, the control terminal of the charge transistor F2 and the operation of the bypass circuit FL.

Please refer to Fig. 1 and Fig. 4, wherein Fig. 1 is a block diagram of a power supply system of a battery pack connected in series according to an embodiment of the present invention; Fig. 4 is a circuit layout diagram of multiple battery packs of a power supply system of a battery pack connected in series according to an embodiment of the present invention . The same content as above, will not be repeated here.

For the convenience of description, one battery pack PAn among the plurality of battery packs PA1 ˜PAn is defined as the last battery pack PAn. The output terminal of the bypass circuit FL of the last battery pack PAn (ie, the second terminal of the first switching element A1 ) can be connected to the input terminal of the power supply circuit 10 . The negative terminal of the battery circuit BST can be connected (via the sense resistor Rs) to the input terminal of the power supply circuit 10 .

The first terminal of the discharge transistor F1 of the battery pack PA1 and the anode of the first internal diode DT of the battery pack PA1 can be directly connected to the output terminal of the power supply circuit 10 .

For each of the battery packs PA1~PAn-1 except the last battery pack PAn, the negative terminal of the battery BYn of the battery circuit BST (through the sensing resistor Rs) can be connected to the input terminal of the power supply circuit 10, and the output terminal of the bypass circuit FL ( That is, the second end of the first switching element A1 is connected to the first end of the discharge transistor F1 of the next battery pack PA2 ˜ PAn and the anode of the first internal diode DT. For example, the output end of the bypass circuit FL of the battery pack PA1 (that is, the second end of the first switching element A1) is connected to the first end of the discharge transistor F1 of the next battery pack PA2 and the anode of the first internal diode DT. .

Please refer to Fig. 1 and Fig. 5, wherein Fig. 1 is the block diagram of the power supply system of the series battery pack of the embodiment of the present invention; Fig. 5 is charging a plurality of battery packs for the power supply circuit of the power supply system of the series battery pack of the embodiment of the present invention usage diagram.

A plurality of battery packs PA1 ˜ PAn are arranged in sequence and connected in series, and these battery packs PA1 ˜ PAn may have the same or different characteristics from each other. Therefore, when the power supply circuit 10 supplies a charging current IS to charge the multiple battery packs PA1˜PAn, the charging current IS will flow through the multiple battery packs PA1˜PAn in sequence, one of the multiple battery packs PA1˜PAn Or more, such as the battery pack PA2, will be fully charged first. The control circuit 20 of the fully charged battery pack PA2 will turn off the charging transistor F2 (and the discharging transistor F1) of the battery pack PA2, so as to prohibit the charging current IS from flowing through the charging transistor F2 (and the discharging transistor F1) to the battery pack The batteries BY1~BYn of PA2 are charged.

In order to avoid that the charging transistor F2 (and the discharging transistor F1) of the fully charged battery pack PA2 is turned off, and the charging current IS cannot flow from the battery pack PA2 to other battery packs PA3~PAn that are not yet fully charged, therefore in the present invention The power supply system of the embodiment is provided with a bypass circuit FL.

When the control circuit 20 of each battery pack PA1 ˜PAn starts to charge, the control circuit 20 turns on the discharge transistor F1 and the charge transistor F2 , but turns off the bypass circuit FL. In this case, as shown in FIG. 5 for the battery pack PA1, the charging current IS supplied by the power supply circuit 10 first flows to the discharge transistor F1 of the battery pack PA1, then flows through the charging transistor F2, and then flows to the batteries BY1~BYn to charge the batteries BY1~BYn.

The charging current IS flows through the batteries BY1˜BYn of the battery pack PA1, and then flows to the sensing resistor Rs. When the charging current IS flows through the sensing resistor Rs of the battery pack PA1, the detection circuit 30 of the battery pack PA1 can detect the parameter data of its internal circuit components, such as the current or voltage of the sensing resistor Rs, to judge the battery Whether all the batteries BY1~BYn of the circuit BST are fully charged.

Before the control circuit 20 of the battery pack PA1 determines that all the batteries BY1~BYn of the battery circuit BST of the battery pack PA1 are fully charged, the control circuit 20 of the battery pack PA1 continues to turn on the discharge transistor F1 and the charge transistor F2, but closes the bypass circuit FL (the first switching element A1 and the second switching element B1). At this time, as shown in FIG. 5 , the charging current IS keeps flowing to the discharging transistor F1 , the charging transistor F2 to the batteries BY1 ˜ BYn in order to charge the batteries BY1 ˜ BYn.

After the charging current IS flows through the batteries BY1 ˜ BYn (and the sensing resistor Rs) of the battery pack PA1 , it will flow to the next battery pack PA2 . The operation of the other battery packs PA2~PAn is the same as that of the above-mentioned battery pack PA1 from the start of charging to the full charge.

In this embodiment, during the process of charging the multiple battery packs PA1~PAn sequentially with the charging current IS, all the batteries BY1~BYn of the battery circuit BST of the battery pack PA2 have been fully charged first, and the other battery packs PA1, PA3 ~PAn (battery circuit BST) is not yet fully charged. In this case, when the control circuit 20 of the battery pack PA2 judges that the battery circuit BST of the battery pack PA2 is fully charged, as shown in FIG. 5, the control circuit 20 of the battery pack PA2 can turn off the charging transistor F2 of the battery pack PA2. (and the discharge transistor F1 ) to prevent the charging current IS from continuing to flow to the battery circuit BST, and stop charging the battery circuit BST.

When the discharge transistor F1 and the discharge transistor F1 of the battery pack PA2 are turned off, the charging path of the charging current IS flowing through the discharge transistor F1 and the charging transistor F2 to the fully charged battery circuit BST is cut off. At this time, the control circuit 20 of the battery pack PA2 turns on the first switching element A1 and the second switching element B1 of the bypass circuit FL to provide a bypass path, so that the charging current IS does not flow to the battery circuit BST of the battery pack PA2 but still continues The current flows to other battery packs PA3~PAn to charge the battery circuits BST of other battery packs PA3~PAn that are not yet fully charged.

In detail, after the charging current IS flows from the battery pack PA1 to the battery pack PA2, the charging current IS flows through the first internal diode DT of the discharge transistor F1 of the battery pack PA2, and then flows through the first internal diode DT of the transformer ST in sequence. side and the first switching element A1, then flows to the next battery pack PA3. At the same time, the current output by the battery circuit BST of the battery pack PA2 may flow through the resistor Rs, the second switch element B1 and the second diode D2 in sequence, and finally return to the battery circuit BST.

When each of the battery packs PA1 ˜ PAn is not fully charged, the operations of the battery packs PA1 ˜ PAn and the flow of the charging current IS are the same as those of the above battery pack PA1 . When each of the battery packs PA1 -PAn is fully charged, the operation of each of the battery packs PA1 -PAn and the flow of the charging current IS are the same as the above battery pack PA2. The same content will not be repeated here.

To sum up, the present invention provides a power supply system for battery packs connected in series. In the process of charging multiple battery packs connected in series, some battery packs will not be charged when they are fully charged. Other battery packs that are not fully charged in series with each other can still continue to charge, so that multiple battery packs in the final power supply system can be fully charged, so that the voltages of multiple battery packs are balanced/close to each other, so that the power supply system has sufficient capacity.

The content disclosed above is only a preferred feasible embodiment of the present invention, and does not therefore limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. within the scope of the patent.

10: Power supply circuit PA1~PAn: battery pack BST: battery circuit BY1~BYn: battery F1: discharge transistor DT: first internal diode F2: charging transistor CT: second internal diode 20: Control circuit FL: bypass circuit S1: voltage source ST: Transformer A1: The first switching element D1: the first diode D2: second diode B1: Second switching element R: resistance 30: Detection circuit Rs: sense resistor IS: charging current

FIG. 1 is a block diagram of a power supply system for a series battery pack according to an embodiment of the present invention.

FIG. 2 is a first circuit layout diagram inside a battery pack of the power supply system for series battery packs according to the embodiment of the present invention.

FIG. 3 is a second circuit layout diagram inside a battery pack of the power supply system for series battery packs according to the embodiment of the present invention.

FIG. 4 is a circuit layout diagram of multiple battery packs in the power supply system of series battery packs according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of the use of the power supply circuit of the power supply system of the series battery packs charging multiple battery packs according to the embodiment of the present invention.

10: Power supply circuit

PA1~PAn: battery pack

BST: battery circuit

BY1~BYn: battery

F1: discharge transistor

DT: first internal diode

F2: charging transistor

CT: second internal diode

20: Control circuit

FL: bypass circuit

S1: voltage source

ST: Transformer

A1: The first switching element

D1: the first diode

D2: second diode

B1: Second switching element

R: resistance

30: Detection circuit

Rs: sense resistor

IS: charging current

Claims (7)

A power supply system for a battery pack in series, comprising: a power supply circuit configured to supply a charging current; A plurality of battery packs, the plurality of battery packs are arranged in sequence and connected in series, and each of the battery packs includes: A battery circuit comprising a plurality of batteries connected in series; A discharge transistor, the first end of the discharge transistor is connected to the anode of a first internal diode of the discharge transistor, and the second end of the discharge transistor is connected to the cathode of the first internal diode; A charging transistor, the first end of the charging transistor is connected to the second end of the discharging transistor and the cathode of a second internal diode of the charging transistor, the second end of the charging transistor is connected to the second the anode of the internal diode and the positive terminal of the battery circuit; a bypass circuit, the positive input terminal of the bypass circuit is connected to the cathode of the first internal diode, and the negative input terminal of the bypass circuit is connected to the negative terminal of the battery pack; and A control circuit, connected to the control terminal of the discharge transistor, the control terminal of the charge transistor and the bypass circuit, configured to turn on the discharge transistor and the charge transistor but turn off when the battery circuit is not fully charged The bypass circuit makes the charging current flow through the battery circuit instead of the bypass circuit, and when the battery circuit is fully charged, the charging transistor is turned off but the bypass circuit is turned on so that the charging current flows through the bypass circuit. bypasses the circuit but does not flow through the battery circuit; Wherein, one of the battery packs in the plurality of battery packs is defined as a final battery pack, the output terminal of the bypass circuit of the last battery pack and the negative terminal of the battery circuit are connected to the input terminal of the power supply circuit, and the other The first end of the discharge transistor of the battery pack is directly connected to the output end of the power supply circuit; Wherein, for each battery pack except the last battery pack, the negative end of the battery circuit and the output end of the bypass circuit are connected to the first end of the discharge transistor of the next battery pack and the first internal two Polar anode. The power supply system of series battery packs as described in claim item 1, wherein the bypass circuit of each battery pack includes: a voltage supply element; A transformer having a first side and a second side opposite to the first side, the first end of the first side of the transformer is connected to the cathode of the first internal diode and the positive end of the voltage supply element ; A first switch element, the first end of the first switch element is connected to the second end of the first side of the transformer, the second end of the first switch element is connected to the negative end of the voltage supply element, the first switch The control terminal of the component is connected to the control circuit; a first diode, the anode of the first diode is connected to the first end of the second side of the transformer; a second diode, the anode of the second diode is connected to the cathode of the first diode, and the cathode of the second diode is connected to the positive terminal of the battery circuit; and A second switch element, the first end of the second switch element is connected to the anode of the second diode, the second end of the second switch element is connected to the second end of the second side of the transformer, the second The control terminal of the switch element is connected to the control circuit; Wherein, the second end of the first switching element and the second end of the second switching element of the last battery pack are connected to the input end of the power supply circuit; Wherein, in each of the battery packs other than the last battery pack, the second end of the first switch element and the second end of the second switch element are connected to the first end of the discharge transistor of the next battery pack . The power supply system of series battery packs as described in claim 2, wherein the bypass circuit of each battery pack further includes a resistor, the first end of the resistor is connected to the cathode of the first diode, and the second end of the resistor terminal connected to the second terminal of the second side of the transformer. The power supply system for series battery packs as claimed in claim 2, wherein the first switching element is a transistor. The power supply system for series battery packs according to claim 2, wherein the second switching element is a transistor. The power supply system of series battery packs as described in claim 1, wherein each of the battery packs further includes a detection circuit connected to the control circuit and the negative terminal of the battery circuit, configured to detect the output/input current of the battery circuit Quantity or voltage value, according to which the control circuit controls the discharge transistor, the charge transistor and the bypass circuit. The power supply system of series battery packs as described in claim item 6, wherein each of the battery packs further includes a sensing resistor, the first end of the sensing resistor is connected to the negative end of the battery circuit and the detection circuit, and the sensing resistor The second end of the resistor is connected to the detection circuit; Wherein, the second end of the sensing resistor of the last battery pack is connected to the input end of the power supply circuit, and the second end of the sensing resistor of each other battery pack is connected to the first discharge transistor of the next battery pack. one end.

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