TWI684316B - Series connected battery switching module and mode switching method and energy storage system - Google Patents

Abstract

A series connected battery switch module includes a battery, a bidirectional switch, a unidirectional current limiting component and a unidirectional switch. The battery has a positive terminal and a negative terminal. The two ends of the bidirectional switch are electrically connected to the positive terminal of the battery and a first node respectively. The two ends of the unidirectional current limiting component are electrically connected to the first node and a second node respectively. The two ends of the unidirectional switch are electrically connected to the first node and the second node respectively. The present patent controls the bidirectional switch and the unidirectional switch to operate the battery in a normal charging/discharging mode or a bypass charging/discharging mode, so that when multiple batteries are used in series, the charging and discharging time can be determined according to their respective states to extend their lifetime.

Description

Series battery switch module, its mode switching method and energy storage system

The invention relates to a series battery, in particular to a series battery switch module.

As the application range of batteries becomes more and more extensive, such as electric vehicles, electric locomotives or green energy storage systems all use batteries as their power sources or energy storage units, but the capacity of a single battery may not meet the ratings required for various applications Voltage or rated current, therefore, connecting multiple batteries in series to increase the output voltage, or connecting multiple batteries in parallel to increase the output current is one of the focuses of battery applications.

With the large-scale application of batteries, the problem of disposal of obsolete batteries is becoming more and more serious. Taking an electric vehicle battery pack as an example, its application scenario will require the battery to output a large amount of energy in an instant, so when the state of health of the electric vehicle battery pack (State of health) When it is reduced to 70%~80% of the new battery, it is no longer suitable for the application of electric vehicles and needs to be eliminated; and the practice of scrapping the battery pack directly is not in line with economic benefits. Re-screening and assembling replacement battery packs will result in high-cost secondary processing costs. If directly applied, they will face different conditions for different battery packs, and the battery pack life will be limited to the worst conditions The battery pack cannot be effectively replaced by the battery pack.

The main purpose of the present invention is to allow the battery to achieve normal charge and discharge, bypass discharge or bypass charge through the bidirectional switch, unidirectional current limiting element and unidirectional switch, so that the battery in poor condition can still be normally connected or merged in It is used in battery packs to extend its service life and maximize the benefits of battery packs.

A series battery switch module of the present invention includes a battery, a bidirectional switch, a unidirectional current limiting element and a unidirectional switch, the battery has a positive terminal and a negative terminal, and the two ends of the bidirectional switch are electrically connected respectively The positive terminal of the battery and a first node, both ends of the one-way current limiting element are electrically connected to the first node and a second node, respectively, and both ends of the one-way switch are electrically connected to the first node, respectively And the second node.

A mode switching method of a series battery switch module of the present invention includes: providing a series battery switch module, the series battery switch module having a battery, a bidirectional switch, a unidirectional current limiting element, and a unidirectional switch, the The battery has a positive terminal and a negative terminal. The two ends of the bidirectional switch are electrically connected to the positive terminal of the battery and a first node. The two ends of the unidirectional current limiting element are electrically connected to the first node and the A second node, the two ends of the one-way switch are electrically connected to the first node and the second node respectively, wherein the two-way switch is turned on and the one-way switch is turned off, so that the battery is in a normal charge and discharge mode, cut off The bidirectional switch also turns on the unidirectional switch to put the battery in a bypass charging mode, and turns off the bidirectional switch and turns off the unidirectional switch to put the battery in a bypass discharge mode.

An energy storage system of the present invention includes a plurality of series-connected battery switch modules and a DC-DC voltage converter. The series-connected battery switch modules are connected in series between a first voltage terminal and a second voltage terminal. The series battery switch module has a battery, a bidirectional switch, a unidirectional current limiting element and a unidirectional switch. The battery has a positive terminal and a negative terminal. The two ends of the bidirectional switch are electrically connected to the battery A positive terminal and a first node, both ends of the one-way current limiting element are electrically connected to the first node and a second node, respectively, and both ends of the one-way switch are electrically connected to the first node and the second node, respectively Node, the DC-DC voltage converter has a first capacitor, a first switch group, an inductor group, a second switch group and a capacitor group, the two ends of the first capacitor are electrically connected to the first voltage terminal and The second voltage terminal, the first switch group is electrically connected to the first voltage terminal and the second voltage terminal, the inductance group is electrically connected to the first switch group and the second switch group, and the second switch group is electrically A third voltage terminal and a fourth voltage terminal are electrically connected, and the capacitor set is electrically connected to the third voltage terminal and the fourth voltage terminal.

The series battery switch module of the present invention allows the battery to be normally charged or discharged or bypassed outside the charge and discharge circuit by the current limit or conduction of the bidirectional switch, the unidirectional current limiting element and the unidirectional switch. This allows the battery in poor condition to still be used in series with the battery in better condition to continue its service life.

Please refer to FIG. 1, which is an embodiment of the present invention, a circuit diagram of a series battery switch module 100, the series battery switch module 100 includes a battery 110, a bidirectional switch 120, a unidirectional current limiting element 130 and a Unidirectional switch 140, the battery 110 has a positive terminal 111 and a negative terminal 112, the two ends of the bidirectional switch 120 are electrically connected to the positive terminal 111 of the battery 110 and a first node n1, the unidirectional current limiting Both ends of the element 130 are electrically connected to the first node n1 and a second node n2, respectively, and both ends of the one-way switch 140 are electrically connected to the first node n1 and the second node n2, respectively. Wherein, the second node n2 of the series battery switch module 100 can be electrically connected to the first node n1 of another series electric switch 100, so that the series battery switch modules 100 form a series structure, and each of the The battery 110 is a charge-discharge battery, which can supply power to the load, or charge the batteries 110 through the power supply.

Please refer to FIGS. 1 and 2(a), the bidirectional switch 120 has a first transistor 121 and a second transistor 122, the first transistor 121 and the second transistor 122 are connected in series at the first node n1 And the positive terminal 111 of the battery 110, in this embodiment, the first transistor 121 and the second transistor 122 are both NMOS transistors, and one of the drains of the first transistor 121 is electrically connected In the first node n1, a source of the first transistor 121 is electrically connected to a source of the second transistor 122, and a drain of the second transistor 122 is electrically connected to the positive terminal of the battery 110 111. By connecting the first transistor 121 and the second transistor 122 in series, the bidirectional switch 120 can prevent the parasitic current from flowing through the first transistor 121 or the second transistor 122 in the off state. The diode flows through. In other embodiments, the bidirectional switch 120 can be replaced by a single controllable switch, such as a relay.

Please refer to FIG. 1, the unidirectional current limiting element 130 is a diode, the unidirectional current limiting element 130 has an anode terminal 131 and a cathode terminal 132, the anode terminal 131 of the unidirectional current limiting element 130 is electrically Connected to the second node n2, the cathode terminal 132 of the unidirectional current limiting element 130 is electrically connected to the first node n1, wherein the unidirectional current limiting element 130 allows current from the second node n2 to pass through the unidirectional limit The current element 130 flows to the first node n1, and prevents current from flowing from the first node n1 to the second node n2 via the unidirectional current limiting element 130.

Please refer to FIGS. 1 and 2(b), the unidirectional switch 140 has a first unidirectional current limiting unit 141 and a switching element 142, the first unidirectional current limiting unit 141 and the switching element 142 are connected in series to the first Between a node n1 and the second node n2. In this embodiment, the first unidirectional current limiting unit 141 is a diode, the switching element 142 is an NMOS transistor, the first unidirectional current limiting unit 141 has an anode terminal 141a and a cathode terminal 141b, The anode terminal 141a of the first unidirectional current limiting unit 141 is electrically connected to the first node n1, the cathode terminal 141b of the first unidirectional current limiting unit 141 is electrically connected to a drain of the switching element 142, the One source of the switching element 142 is electrically connected to the second node n2. When the switching element 142 is turned off, the first unidirectional current limiting unit 141 and the switching element 142 can prevent current from flowing from the second node n2 to the first node n1 through the unidirectional switch 140, and the switching element When 142 is turned on, the first unidirectional current limiting unit 141 and the switching element 142 can allow current to flow from the first node n1 through the unidirectional switch 140 to the second node n2. In other embodiments, the one-way switch 140 can be replaced by a single controllable switch, such as a relay.

Please refer to FIGS. 3, 4 and 5 for schematic diagrams of a plurality of series-connected battery switch modules 100 connected in series with each other. There are only four series-connected battery switch modules 100 connected in series. In other embodiments, more Or less of the series-connected battery switch module 100, the number of series connection is not limited by the present invention. By controlling the bidirectional switch 120 and the unidirectional switch 140 of each series battery switch module 100, each battery 110 can be operated in three modes.

Please refer to FIG. 3 first, taking the battery 110 of the series-connected battery switch module 100 at the top as an example, if the battery 110 is in a stage where it can be normally connected to a loop for charging and discharging, a control unit ( (Not shown in the figure) output a control signal to the bidirectional switch 120 and the unidirectional switch 140 to turn on the bidirectional switch 120 and turn off the unidirectional switch 140, so that the battery 110 operates in a normal charge and discharge mode. At this time, the The output current of the battery 110 may flow to the first node n1 through the bidirectional switch 120 to be discharged, or the current may flow into the battery 110 through the bidirectional switch 120 from the first node n1 to be charged.

Please refer to FIG. 4, if the battery 110 of the series battery switch module 100 at the top is charged earlier than the battery 110 of the other series battery switch module 100, in order to prevent the battery 110 from being overcharged, The control unit can output a control signal to the bidirectional switch 120 and the unidirectional switch 140 to turn off the bidirectional switch 120 and turn on the unidirectional switch 140, so that the battery 110 operates in a bypass charging mode. The bidirectional switch 120 is off and the unidirectional switch 140 is on, so the loop current does not flow to the battery 110, but will bypass the unidirectional switch 140 and then flow to the other series battery switch module 100 In this way, the over-charged battery 110 may be prevented from being damaged or being damaged.

Please refer to FIG. 5, if the battery 110 of the series battery switch module 100 at the top is in the process of discharging, the output current capability of the battery 110 is smaller than that of the other series battery switch modules 110, which may affect When the output current of the whole circuit is output, the control unit can output a control signal to the bidirectional switch 120 and the unidirectional switch 140 to cut off the bidirectional switch 120 and the unidirectional switch 140, so that the battery 110 is in a bypass discharge mode At this time, since the bidirectional switch 120 and the unidirectional switch 140 are off, the loop current does not flow to the battery 110 and the unidirectional switch 140, but bypasses to the unidirectional current limiting element 130. In this way, the battery 110 with a lower output current can be prevented from affecting other batteries 110.

Since each of the series-connected battery switch modules 100 can change the number of the series-connected batteries through the switching of the switches, the output voltage thereof changes accordingly. Therefore, it is preferable to convert the potential of the output voltage through a voltage converter. The potential of the output voltage can be stabilized. Or, when the number of the batteries connected in series changes, the required charging voltage also changes. Therefore, the potential of the charging voltage can be converted through the voltage converter to make the potential of the charging voltage conform to the batteries of different numbers in series.

Please refer to FIG. 6 for a schematic circuit diagram of an energy storage system R, wherein the energy storage system R includes a plurality of series-connected battery switch modules 100 and a DC-DC voltage converter 200, and the series-connected battery switch modules 100 are connected in series Between a first voltage terminal V1 and a second voltage terminal V2, the structure and operation mode of each series battery switch module 100 are the same as those in FIGS. 1 to 5, and will not be repeated here. In this embodiment, the DC-DC voltage converter 200 has a first capacitor 210, a first switch group 220, an inductor group 230, a second switch group 240, and a capacitor group 250, wherein the first Both ends of the capacitor 210 are electrically connected to the first voltage terminal V1 and the second voltage terminal V2, the first switch group 220 is electrically connected to the first voltage terminal V1 and the second voltage terminal V2, and the inductor group 230 is electrically The first switch group 220 and the second switch group 240 are electrically connected, the second switch group 240 is electrically connected to a third voltage terminal V3 and a fourth voltage terminal V4, and the capacitor group 250 is electrically connected to the third voltage Terminal V3 and the fourth voltage terminal V4.

Please refer to FIG. 6, in this embodiment, the first switch group 220 has a first switch 221, a second switch 222, a seventh switch 223 and an eighth switch 224, the first switch 221 and the One end of the second switch 222 is electrically connected to the first voltage terminal V1, the other end of the first switch 221 is electrically connected to one end of the seventh switch 223, and the other end of the second switch 222 is electrically connected to the eighth switch At one end of 224, the other end of the seventh switch 223 is electrically connected to the second voltage terminal V2, and the other end of the eighth switch 224 is electrically connected to the second voltage terminal V2.

The inductance group 230 has a first inductance 231 and a second inductance 232. One end of the first inductance 231 is electrically connected to the other end of the first switch 221 and one end of the seventh switch 223. The other end is electrically connected to a third node n3, one end of the second inductor 232 is electrically connected to the other end of the second switch 222 and one end of the eighth switch 224, and the other end of the second inductor 232 is electrically connected to a The fourth node n4.

The second switch group 240 has a third switch 241, a fourth switch 242, a fifth switch 243, and a sixth switch 244. One ends of the third switch 241 and the fifth switch 243 are electrically connected to the third At node n3, one end of the fourth switch 242 is electrically connected to the fourth node n4, the other ends of the third switch 241 and the fourth switch 242 are electrically connected to the second voltage terminal V2, and the other of the fifth switch 243 One end is electrically connected to the third voltage terminal V3, one end of the sixth switch 244 is electrically connected to the second voltage terminal V2, and the other end of the sixth switch 244 is electrically connected to the fourth voltage terminal V4.

The capacitor set 250 has a second capacitor 251 and a third capacitor 252, one end of the second capacitor 251 is electrically connected to the third voltage terminal V3, and the other end of the second capacitor 251 is electrically connected to the fourth node n4 One end of the third capacitor 252 is electrically connected to the fourth node n4, and the other end of the third capacitor 252 is electrically connected to the fourth voltage terminal V4.

Wherein, the DC-DC voltage converter 200 can control the switches, and the first voltage terminal V1 and the second voltage terminal V2 are used to input voltage and the third voltage terminal V3 and the fourth voltage The terminal V4 is used to output a discharge mode of the voltage, or at the third voltage terminal V3 and the fourth voltage terminal V4 for input voltage and the first voltage terminal V1 and the second voltage terminal V2 for output voltage Charging mode. And through the distribution of the duty cycles of the switches, the DC-DC voltage converter 200 has a high voltage step-up/down ratio. Since the series battery switch modules 100 may change due to the change in the number of battery series, the first voltage terminal The voltage difference between V1 and the second voltage terminal V2 may vary greatly. Therefore, the high voltage step-up/down ratio of the DC-DC voltage converter 200 is quite suitable for its requirements.

The series battery switch module 100 of the present invention allows the battery 110 to be normally charged or discharged or bypassed by the current limiting or conduction of the bidirectional switch 120, the unidirectional current limiting element 130 and the unidirectional switch 140 Outside the charging and discharging circuit, the battery in poor condition can still be used in series with the battery in better condition to extend its service life.

The scope of protection of the present invention shall be subject to the scope defined in the attached patent application. Any changes and modifications made by those who are familiar with this skill without departing from the spirit and scope of the present invention shall fall within the scope of protection of the present invention. .

100‧‧‧series battery switch module

110‧‧‧ battery

111‧‧‧Extreme

112‧‧‧Negative terminal

120‧‧‧Two-way switch

121‧‧‧ First transistor

122‧‧‧Second transistor

130‧‧‧One-way current limiting element

131‧‧‧Anode

132‧‧‧Cathode

140‧‧‧One-way switch

141‧‧‧First unidirectional current limiting unit

142‧‧‧Switching element

141a‧‧‧Anode

141b‧‧‧Cathode

200‧‧‧DC-DC voltage converter

210‧‧‧ First capacitor

220‧‧‧ First switch group

221‧‧‧First switch

222‧‧‧ Second switch

223‧‧‧The seventh switch

224‧‧‧Eighth switch

230‧‧‧Inductance group

231‧‧‧The first inductance

232‧‧‧Second inductor

240‧‧‧Second switch group

241‧‧‧The third switch

242‧‧‧The fourth switch

243‧‧‧ fifth switch

244‧‧‧Sixth switch

250‧‧‧capacitor group

251‧‧‧Second capacitor

252‧‧‧The third capacitor

n1‧‧‧First node

n2‧‧‧The second node

n3‧‧‧The third node

n4‧‧‧The fourth node

R‧‧‧Energy storage system

V1‧‧‧ First voltage terminal

V2‧‧‧Second voltage terminal

V3‧‧‧The third voltage terminal

V4‧‧‧ fourth voltage terminal

Figure 1: A circuit diagram of a series battery switch module according to an embodiment of the present invention. Figure 2: Circuit diagram of a bidirectional switch and a unidirectional switch according to an embodiment of the invention. Figure 3: A schematic diagram of the series battery switch module operating in a normal charge and discharge mode according to an embodiment of the present invention. Fig. 4: According to an embodiment of the present invention, a schematic diagram of the series battery switch module operating in the bypass charging mode. Figure 5: A schematic diagram of the series battery switch module operating in the bypass discharge mode according to an embodiment of the present invention. Fig. 6: A circuit diagram of an energy storage system according to an embodiment of the invention.

100‧‧‧series battery switch module

110‧‧‧ battery

111‧‧‧Extreme

112‧‧‧Negative terminal

120‧‧‧Two-way switch

130‧‧‧One-way current limiting element

131‧‧‧Anode

132‧‧‧Cathode

140‧‧‧One-way switch

141‧‧‧First unidirectional current limiting unit

141a‧‧‧Anode

141b‧‧‧Cathode

142‧‧‧Switching element

n1‧‧‧First node

n2‧‧‧The second node

Claims (10)

A series battery switch module includes: a battery having a positive terminal and a negative terminal; a bidirectional switch, the two ends of which are electrically connected to the positive terminal of the battery and a first node; a unidirectional current limiting Element, the two ends of which are electrically connected to the first node and a second node, the negative terminal of the battery is electrically connected to the second node; and a one-way switch, the two ends of which are respectively electrically connected to the first node And the second node; wherein, the bidirectional switch does not have a bypass diode, when the series battery switch module is in a normal charge and discharge mode, the bidirectional switch is turned on and the unidirectional switch is turned off so that current flows through the bidirectional switch. The series battery switch module as described in item 1 of the patent application scope, wherein the bidirectional switch has a first transistor and a second transistor, the first transistor and the second transistor are connected in series at the first node And the positive end of the battery. The series battery switch module as described in item 2 of the patent application scope, wherein the first transistor and the second transistor are both NMOS transistors, and a drain of the first transistor is electrically connected to the first node , A source of the first transistor is electrically connected to a source of the second transistor, and a drain of the second transistor is electrically connected to the positive terminal of the battery. The series battery switch module as described in item 1 of the patent application scope, wherein the unidirectional current limiting element is a diode, the unidirectional current limiting element has an anode terminal and a cathode terminal, the unidirectional current limiting element The anode terminal is electrically connected to the second node, and the cathode terminal of the one-way current limiting element is electrically connected to the first node. The series battery switch module as described in item 1 of the patent application range, wherein the unidirectional switch has a first unidirectional current limiting unit and a switching element, the first unidirectional current limiting unit and the switching element string Is connected between the first node and the second node. A series battery switch module as described in item 5 of the patent application range, wherein the first unidirectional current limiting unit is a diode, the switching element is an NMOS transistor, and the first unidirectional current limiting unit has a positive Extreme pole and a cathode end, the anode end of the first unidirectional current limiting unit is electrically connected to the first node, the cathode end of the first unidirectional current limiting unit is electrically connected to a drain of the switching element, the One source of the switching element is electrically connected to the second node. A mode switching method for a series battery switch module includes: providing a series battery switch module, the series battery switch module having a battery, a bidirectional switch, a unidirectional current limiting element, and a unidirectional switch, the battery It has a positive terminal and a negative terminal. The two ends of the bidirectional switch are electrically connected to the positive terminal of the battery and a first node. The two ends of the unidirectional current limiting element are electrically connected to the first node and a terminal In the second node, the negative terminal of the battery is electrically connected to the second node, and both ends of the unidirectional switch are electrically connected to the first node and the second node, respectively, wherein the bidirectional switch does not have a bypass diode And current flows through the bidirectional switch; turning on the bidirectional switch and turning off the unidirectional switch to put the battery in a normal charge and discharge mode; turning off the bidirectional switch and turning on the unidirectional switch to put the battery in a bypass charging mode; and Turning off the bidirectional switch and turning off the unidirectional switch puts the battery in a bypass discharge mode. An energy storage system includes: a plurality of series battery switch modules connected in series between a first voltage terminal and a second voltage terminal, wherein each of the series battery switch modules has a battery, a bidirectional switch, and a single The current limiting element and a unidirectional switch, the battery has a positive terminal and a negative terminal, the two ends of the bidirectional switch are electrically connected to the positive terminal of the battery and a first node, the unidirectional current limiting element Both ends are electrically connected to the first node and a second node, the negative terminal of the battery is electrically connected to the second node, and the two ends of the one-way switch are electrically Connecting the first node and the second node, wherein each bidirectional switch does not have a bypass diode, and when each series battery switch module is in a normal charge and discharge mode, each bidirectional switch is turned on and each unidirectional The switch is turned off so that current flows through the bidirectional switch; and a DC-DC voltage converter has a first capacitor, a first switch group, an inductor group, a second switch group, and a capacitor group, the first capacitor Both ends are electrically connected to the first voltage end and the second voltage end, the first switch group is electrically connected to the first voltage end and the second voltage end, and the inductance group is electrically connected to the first switch group and the In the second switch group, the second switch group is electrically connected to a third voltage terminal and a fourth voltage terminal, and the capacitor group is electrically connected to the third voltage terminal and the fourth voltage terminal. The energy storage system as described in item 8 of the patent application range, wherein the first switch group has a first switch and a second switch, and one end of the first switch and the second switch is electrically connected to the first voltage end , The inductance group has a first inductance and a second inductance, one end of the first inductance is electrically connected to the other end of the first switch, the other end of the first inductance is electrically connected to a third node, the second One end of the inductor is electrically connected to the other end of the second switch, the other end of the second inductor is electrically connected to a fourth node, and the second switch group has a third switch, a fourth switch, a fifth switch and A sixth switch, one end of the third switch and the fifth switch is electrically connected to the third node, one end of the fourth switch is electrically connected to the fourth node, the other end of the third switch and the fourth switch The second voltage terminal is electrically connected, the other terminal of the fifth switch is electrically connected to the third voltage terminal, one terminal of the sixth switch is electrically connected to the second voltage terminal, and the other terminal of the sixth switch is electrically connected For the fourth voltage terminal, the capacitor group has a second capacitor and a third capacitor, one end of the second capacitor is electrically connected to the third voltage terminal, and the other end of the second capacitor is electrically connected to the fourth node, One end of the third capacitor is electrically connected to the fourth node, and the other end of the third capacitor is electrically connected to the fourth voltage terminal. The energy storage system as described in item 9 of the patent application scope, wherein the first switch group has another A seventh switch and an eighth switch, one end of the seventh switch is electrically connected to the other end of the first switch and one end of the first inductor, and the other end of the seventh switch is electrically connected to the second voltage end, One end of the eighth switch is electrically connected to the other end of the second switch and one end of the second inductor, and the other end of the eighth switch is electrically connected to the second voltage end.

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