Battery pack parallel connection circuit and energy storage device

Abstract

The present invention provides a parallel connection circuit for battery packs, which includes a plurality of battery packs and a corresponding plurality of transmission circuits. A voltage conversion module is provided on each transmission circuit, and the battery packs are respectively electrically connected to the DC bus through the voltage conversion modules corresponding to them; a shunt switch is provided between the transmission circuits. When a certain transmission circuit is disconnected, the shunt switch closes, and the direct current output by the battery pack on another transmission circuit is shunted by the shunt switch. One path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other path flows through the voltage conversion module on the disconnected transmission circuit through the closed shunt switch to the DC bus. In the technical solution, the power output of the battery packs is shunted and output to a plurality of voltage conversion modules for power sharing, and each voltage conversion module will operate with a small power, reducing the heat generation of the voltage conversion module and lowering the temperature rise of the parallel connection circuit for battery packs. The present invention also relates to an energy storage device based on the parallel connection circuit for battery packs.

Description

Technical Field

[0001] The present invention relates to a parallel connection circuit for battery packs and an energy storage device. Background Art

[0002] The prior art CN102122826A (filing date: January 17, 2011; publication date: July 13, 2011) discloses a large-capacity battery energy storage bidirectional converter, which supports the access of multiple branch DC / DC module units. Each battery branch collects DC energy to the DC bus, and then is connected to the AC grid or operates independently with a load through the subsequent DC / AC converter. In this way, it can take into account the characteristics of the wide-range voltage variation at the battery pack end, adopt a two-stage (DC / DC + DC / AC) multi-group access structure, reduce the capacity of a single battery branch, reduce the number of series and parallel connections of batteries, and solve the problems of circulating current and current sharing in the series and parallel connections of battery packs. However, the above solution has technical problems such as high cost and large heat generation, which need to be improved. Summary of the Invention

[0003] The present invention aims to solve the above technical problems to provide a parallel connection circuit for battery packs and an energy storage device based on the parallel connection circuit for battery packs.

[0004] A parallel connection circuit for battery packs provided by the present invention includes:

[0005] Multiple battery packs, which are adapted to output direct current;

[0006] Multiple transmission circuits provided corresponding to the multiple battery packs one by one;

[0007] A voltage conversion module is configured on each of the transmission circuits;

[0008] The multiple battery packs are respectively electrically connected to the DC bus through the corresponding voltage conversion modules; wherein,

[0009] A shunt switch is further provided between the transmission circuits. When a certain transmission circuit is disconnected, a shunt switch connected to the disconnected transmission circuit is closed, and the direct current output by the battery pack on another transmission circuit connected to the closed shunt switch is shunted. One path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other path flows through the voltage conversion module on the disconnected transmission circuit through the closed shunt switch to the DC bus.

[0010] Further, the output of the battery pack corresponding to a single transmission circuit is adapted to be shunted through the closed shunt switch to meet the maximum power output of multiple transmission circuits or the maximum power output of the battery pack itself.

[0011] Further, it also includes a micro - control unit, which is adapted to control the shunt switch to selectively disconnect or close.

[0012] Further, the shunt switch is a normally - open switch.

[0013] Further, when all the transmission circuits are conducting, the shunt switch remains open.

[0014] Further, the voltage conversion module on each of the transmission circuits is adapted to output a consistent voltage or voltages with a difference less than 0.1V.

[0015] Further, it also includes a power switch, which is placed between the battery pack and the voltage conversion module.

[0016] Further, the shunt switch and the power switch are respectively controlled by the micro - control unit to selectively disconnect or close.

[0017] Further, when the battery pack is not connected to the transmission circuit or when the discharge cut - off voltage of the battery pack is lower than a preset threshold, the micro - control unit controls the power switch to disconnect.

[0018] Further, the battery pack includes a built - in discharge switch and a BMS protection board. When the discharge cut - off voltage of the battery pack is lower than a preset threshold, the BMS protection board controls the discharge switch to disconnect.

[0019] Further, the voltage conversion module is a DC / DC module or a bidirectional DC / DC module.

[0020] Another parallel - connection circuit for battery packs provided by the present invention includes:

[0021] Multiple battery packs, which are adapted to output direct current;

[0022] Multiple transmission circuits respectively arranged corresponding to the multiple battery packs;

[0023] A voltage conversion module is configured on each of the transmission circuits;

[0024] The multiple battery packs are respectively electrically connected to the DC bus through their corresponding voltage conversion modules;

[0025] A shunt switch is also arranged between the transmission circuits; wherein,

[0026] The parallel - connection circuit for battery packs includes at least a first output mode and a second output mode:

[0027] When the first output mode is that each of the transmission circuits is turned on, the shunt switch is turned off, and the battery packs corresponding to each of the transmission circuits are electrically connected to the DC bus through the corresponding voltage conversion modules;

[0028] When the second output mode is that a certain transmission circuit is turned off, one of the shunt switches connected to the turned-off transmission circuit is closed, and the direct current output by the battery pack on the other transmission circuit is shunted through the closed shunt switch. One path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other path flows through the voltage conversion module on the turned-off transmission circuit through the closed shunt switch to the DC bus.

[0029] Another parallel connection circuit for battery packs provided by the present invention includes:

[0030] N battery packs, each of which is adapted to output direct current, N>2;

[0031] Transmission circuits provided in one-to-one correspondence with the battery packs;

[0032] A voltage conversion module is configured on each of the transmission circuits;

[0033] The battery packs are respectively electrically connected to the DC bus through the corresponding voltage conversion modules; wherein,

[0034] A connection node is configured between the output of the battery pack and the input of the voltage conversion module on each of the transmission circuits,

[0035] A shunt switch is provided between the connection nodes. When a certain transmission circuit is turned off, one of the shunt switches on both sides of the connection node on the turned-off transmission circuit is turned off and the other is closed, and the remaining shunt switches are turned off according to a preset control logic;

[0036] A transmission circuit is connected to the closed shunt switch, and the direct current output by the corresponding battery pack is shunted through the closed shunt switch. One path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other path flows through the voltage conversion module on the turned-off transmission circuit through the closed shunt switch to the DC bus.

[0037] Further, when it is detected that only one of the transmission circuits is turned on, the shunt switches on both sides of the connection node on the turned-on transmission circuit are both closed, and the direct current output by the corresponding battery pack is shunted through the closed shunt switches. One path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other two paths flow through the voltage conversion modules on the turned-off transmission circuits through the closed shunt switches to the DC bus.

[0038] Further, the preset control logic includes:

[0039] Compare the voltages of the battery packs on the transmission circuits connected to the other ends of the shunt switches on both sides of the connection node;

[0040] Close the shunt switch connected to the side of the battery pack with a higher voltage, and open the shunt switch connected to the side of the battery pack with a lower voltage.

[0041] Another parallel connection circuit for battery packs provided by the present invention includes:

[0042] Multiple battery packs, which are adapted to output direct current;

[0043] Multiple transmission circuits provided corresponding to the multiple battery packs one by one;

[0044] A voltage conversion module is configured on each of the transmission circuits;

[0045] The multiple battery packs are respectively electrically connected to the DC bus through their corresponding voltage conversion modules; wherein,

[0046] A first node is configured between the output of the battery pack and the input of the voltage conversion module, and the first node is connected to a first shunt switch and a second shunt switch;

[0047] The other end of the first shunt switch is connected to a first transmission circuit;

[0048] The other end of the second shunt switch is connected to a second transmission circuit;

[0049] When it is detected that the transmission circuit configured with the first node is disconnected, one of the first shunt switch and the second shunt switch is controlled to be disconnected and the other is closed according to a preset control logic, and the direct current output by the battery pack on the first transmission circuit or the second transmission circuit is shunted through the closed shunt switch. One path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other path flows through the voltage conversion module on the disconnected transmission circuit through the closed shunt switch to the DC bus.

[0050] An energy storage device provided by the present invention includes:

[0051] The parallel connection circuit for battery packs as described above;

[0052] A DC / AC module, which is electrically connected to the DC bus and is adapted to invert the direct current converged and output by the DC bus into alternating current.

[0053] Further, the DC / AC module is a bidirectional DC / AC module.

[0054] Further, it further includes: connection ports, which are arranged in one-to-one correspondence with the battery packs, are adapted to mechanically and electrically connect the battery packs, and are detachably connected to the battery packs.

[0055] Further, when any one of the battery packs is connected to the connection port, it is adapted to supply power to the first power device through the battery pack parallel connection circuit and the DC / AC module; when any one of the battery packs is detached and removed from the connection port, the battery pack is also adapted to supply power to the second power device.

[0056] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are as follows:

[0057] The power output of the battery pack can be shunted through the shunt switch and output to multiple voltage conversion modules for power sharing. Each voltage conversion module will operate with a small power, which can reduce the heat generation of the voltage conversion module and lower the temperature rise of the battery pack parallel connection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0059] Figure 1 : Schematic block diagram of the principle of specific embodiments of the present invention.

[0060] Figure 2 : Schematic block diagram of the principle of the parallel connection circuit of two battery packs in specific embodiments of the present invention.

[0061] Figure 3 : Schematic block diagram of the principle of specific embodiments of the present invention including a power switch.

[0062] Figure 4 : Schematic block diagram of the principle of self-protection of battery packs in specific embodiments of the present invention.

[0063] Figure 5 : Schematic block diagram of the principle of self-protection of battery packs including a power switch in specific embodiments of the present invention.

[0064] Figure 6 : Schematic block diagram of the parallel connection circuit of N battery packs in specific embodiments of the present invention.

[0065] Figure 7 : Schematic block diagram of the parallel connection circuit of three battery packs in specific embodiments of the present invention.

[0066] Figure 8 : Schematic block diagram of the parallel connection circuit principle when only one transmission circuit is conducting among the three battery packs in the specific embodiment of the present invention.

[0067] Figure 9 : Schematic diagram of the principle of the energy storage device in the specific embodiment of the present invention.

[0068] Figure 10 : Schematic diagram of the structure of the energy storage device in the specific embodiment of the present invention. Specific implementation manners

[0069] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0070] Referring to Figure 1 A battery pack parallel connection circuit 100 shown, which includes:

[0071] A plurality of battery packs 10, which are adapted to output direct current;

[0072] A plurality of transmission circuits 20 provided corresponding to the plurality of battery packs 10 one by one;

[0073] A voltage conversion module 30 is configured on each transmission circuit 20;

[0074] The plurality of battery packs 10 are respectively electrically connected to the DC bus 40 through the voltage conversion modules 30 corresponding to them; among them,

[0075] A shunt switch 50 is further provided between the transmission circuits 20. When a certain transmission circuit 20 is disconnected, the shunt switch 50 connected thereto is closed, and the direct current output by the battery pack 10 on the transmission circuit 20 connected to the other closed shunt switch 50 is shunted through the closed shunt switch 50. One path flows through the voltage conversion module 30 on the original transmission circuit 20 to the DC bus 40, and the other path flows through the voltage conversion module 30 on the disconnected transmission circuit 20 through the closed shunt switch 50 to the DC bus 40.

[0076] This battery pack parallel connection circuit 100 includes at least a first output mode and a second output mode:

[0077] The first output mode is that when each transmission circuit 20 is conducting, the shunt switch 50 is disconnected, and the battery pack 10 corresponding to each transmission circuit 20 is electrically connected to the DC bus 40 through the corresponding voltage conversion module 30;

[0078] When the second output mode is that a certain transmission circuit 20 is disconnected, a shunt switch 50 connected to the disconnected transmission circuit 20 is closed, and the direct current output by the battery pack 10 on the other transmission circuit 20 is shunted by the closed shunt switch 50. One path flows through the voltage conversion module 30 on the original transmission circuit 20 to the DC bus 40, and the other path flows through the voltage conversion module 30 on the disconnected transmission circuit 20 through the closed shunt switch 50 to the DC bus 40.

[0079] Specifically, referring to Figure 2 the shown battery pack parallel connection circuit 100 includes a first battery pack 10a and a second battery pack 10b. The first battery pack 10a corresponds to the first transmission circuit 20a, and the second battery pack 10b corresponds to the second transmission circuit 20b. A first voltage conversion module 30a is configured on the first transmission circuit 20a, and a second voltage conversion module 30b is configured on the second transmission circuit 20b. The first battery pack 10a is electrically connected to the DC bus 40 through the first voltage conversion module 30a corresponding to it, and the second battery pack 10b is electrically connected to the DC bus 40 through the second voltage conversion module 30b corresponding to it. A shunt switch 50 is also provided between the first transmission circuit 20a and the second transmission circuit 20b.

[0080] Output mode one:

[0081] The first battery pack 10a and the second battery pack 10b are respectively connected to the first transmission circuit 20a and the second transmission circuit 20b. The shunt switch 50 is disconnected. The first battery pack 10a is electrically connected to the DC bus 40 through the first voltage conversion module 30a, and the second battery pack 10b is electrically connected to the DC bus 40 through the second voltage conversion module 30b.

[0082] Output mode two:

[0083] The first transmission circuit 20a is disconnected, and the disconnection point is located at the front end of the connection node N on the transmission circuit. The shunt switch 50 is closed, and the direct current output by the second battery pack 10b on the second transmission circuit 20b is shunted by the shunt switch 50. Referring to Figure 2 the direction indicated by the arrow in, one path flows through the original transmission circuit, that is, the second voltage conversion module 30b on the second transmission circuit 20b to the DC bus 40, and the other path flows through the closed shunt switch 50 through the disconnected transmission circuit, that is, the first voltage conversion module 30a on the first transmission circuit 20a to the DC bus 40; or,

[0084] The second transmission circuit 20b is disconnected, and the disconnection point is at the front end of the transmission circuit connected to the node N. The shunt switch 50 is closed. The direct current output by the first battery pack 10a on the first transmission circuit 20a is shunted by the shunt switch 50. One path flows through the original transmission circuit, that is, through the first voltage conversion module 30a on the first transmission circuit 20a to the DC bus 40, and the other path flows through the closed shunt switch 50 and the disconnected transmission circuit, that is, through the second voltage conversion module 30b on the second transmission circuit 20b to the DC bus 40.

[0085] In this way, the power output of the second battery pack 10b can be shunted through the shunt switch 50 and output to the first voltage conversion module 30a and the second voltage conversion module 30b for power sharing. Each voltage conversion module will work with low power, which can reduce the heat generation of the voltage conversion module and lower the temperature rise of the battery pack parallel connection circuit 100.

[0086] Further, when P1max ≥ P1 + P2 and P2max ≥ P1 + P2, when any one of the transmission circuits is disconnected, the battery pack connected to the other transmission circuit will be shunted through the shunt switch 50 and output to the first voltage conversion module 30a and the second voltage conversion module 30b to meet the maximum power output of the first voltage conversion module 30a and the second voltage conversion module 30b, so that a single battery pack can achieve the maximum power output of multiple transmission circuits, and even achieve the maximum power output of the DC bus 40. In the application of the energy storage device 200, a single battery pack can also meet the rated power output of the inverter. In contrast, in the prior art CN102122826A, only when both battery packs are connected to the transmission circuit can the maximum power output of the DC bus and the rated power output of the inverter be achieved.

[0087] When P1 + P2 > P1max and P1 + P2 > P2max, when any one of the transmission circuits is disconnected, the battery pack connected to the other transmission circuit will be shunted through the shunt switch 50 and output to the first voltage conversion module 30a and the second voltage conversion module 30b so as to meet the maximum power output of this battery pack.

[0088] Among them, the above P1max is the maximum output power of the first battery pack 10a, P2max is the maximum output power of the second battery pack 10b; P1 is the maximum output power of the first voltage conversion module 30a, and P2 is the maximum output power of the second voltage conversion module 30b.

[0089] Briefly illustrate with an example:

[0090] Set P1max = P2max = 400W, P1 = P2 = 150w. At this time, P1max > P1 + P2 and P2max > P1 + P2;

[0091] When the first transmission circuit 20a is disconnected and the shunt switch 50 is closed, the direct current output by the second battery pack 10b on the second transmission circuit 20b is shunted by the shunt switch 50. The output of the second battery pack 10b can satisfy the voltage conversion module 30a and the second voltage conversion module 30b on each transmission circuit to output at a maximum output power of 150W, so that only a single second battery pack 10b can achieve the maximum power output of the first transmission circuit 20a and the second transmission circuit 20b. In this specific embodiment, the maximum power output of the DC bus 40 can also be achieved. In the application of the energy storage device 200, only a single second battery pack 10b can also satisfy the rated power output of the inverter.

[0092] It can be understood that according to the technical solution of the prior art CN102122826A, when the first transmission circuit 20a is disconnected and the second battery pack 10b needs to achieve the maximum power output of the DC bus 40 at basically 300W, the maximum output power of the second voltage conversion module 30b needs to be set to 300W. In this way, on the one hand, the cost is increased, and the heat generation of the second voltage conversion module 30b is also large.

[0093] It can be seen that the technical solution of the present invention has lower cost and less heat generation than the prior art.

[0094] Set P1max = P2max = 400W, P1 = P2 = 300w. At this time, P1 + P2 > P1max, P1 + P2 > P2max;

[0095] When the first transmission circuit 20a is disconnected and the shunt switch 50 is closed, the direct current output by the second battery pack 10b on the second transmission circuit 20b is shunted by the shunt switch 50 and will output at a power of basically 200W for each transmission circuit, so as to satisfy the maximum power output of the second battery pack 10b.

[0096] Similarly, it can be understood that according to the technical solution of the prior art CN102122826A, when the first transmission circuit 20a is disconnected, the second battery pack 10b can only output at a power of basically 300W and cannot achieve the maximum power output.

[0097] In summary, the technical solution of the present invention has the beneficial technical effects of lower cost and less heat generation than the prior art.

[0098] Furthermore, the shunt switch 50 is a normally open switch. Of course, it can also be a normally closed switch.

[0099] When the shunt switch 50 is a normally open switch, when a certain transmission circuit 20 is disconnected, the shunt switch 50 needs to be controlled to close, and when it is detected that all the transmission circuits 20 are conducting, the shunt switch 50 is controlled to remain open.

[0100] When the shunt switch 50 is a normally closed switch, when a certain transmission circuit 20 is disconnected, it is necessary to control the shunt switch 50 to remain closed, and when it is detected that all the transmission circuits 20 are conducting, the shunt switch 50 is controlled to open.

[0101] Specifically, the above-mentioned shunt switch 50 is electrically connected to a microcontroller unit (MCU) and is controlled by the microcontroller unit to selectively open or close.

[0102] The above-mentioned shunt switch 50 can be a field effect transistor ("FET") switch or a relay, such as a MOSFET.

[0103] When the shunt switch 50 is a normally open switch, when the microcontroller unit (MCU) detects that a certain transmission circuit 20 is disconnected, the shunt switch 50 is controlled to close through the microcontroller unit (MCU), and when the microcontroller unit (MCU) detects that all the transmission circuits 20 are conducting, the microcontroller unit (MCU) controls the shunt switch 50 to remain open.

[0104] When the shunt switch 50 is a normally closed switch, when the microcontroller unit (MCU) detects that a certain transmission circuit 20 is disconnected, the microcontroller unit (MCU) controls the shunt switch 50 to remain closed, and when the microcontroller unit (MCU) detects that all the transmission circuits 20 are conducting, the microcontroller unit (MCU) controls the shunt switch 50 to open.

[0105] In addition, continuing to refer to Figure 1 and Figure 2 As shown, the voltage conversion module 30 on each transmission circuit 20 is adapted to output substantially the same voltage, and the substantially the same voltage means that the voltage conversion modules 30 on each transmission circuit 20 output the same and consistent voltage.

[0106] In this way, when multiple battery packs are connected to the transmission circuit 20, it can be ensured that the voltages output by the voltage conversion modules 30 on each transmission circuit 20 are balanced, effectively preventing the battery packs from reverse charging.

[0107] Referring to Figure 3 As shown, the battery pack parallel connection circuit 100 further includes a power switch 60, and the power switch 60 is placed between the battery pack 10 and the voltage conversion module 30, and the power switch 60 is also controlled by the microcontroller unit (MCU) to selectively open or close.

[0108] Specifically, the battery pack 10 is communicatively connected to a microcontroller unit (MCU). When the battery pack 10 is connected to the corresponding transmission circuit 20 and the communication is successfully established, the microcontroller unit (MCU) controls the power switch 60 on the corresponding transmission circuit 20 to close; otherwise, the power switch remains open. In addition, when the microcontroller unit (MCU) detects an abnormality in the battery pack 10 or receives an abnormality message of the battery pack 10, such as the discharge cut-off voltage being lower than a preset threshold, the microcontroller unit (MCU) controls the power switch 60 on the corresponding transmission circuit 20 to open.

[0109] In this way, when the battery pack 10 is not connected to the transmission circuit 20 or the information of the battery pack 10 is abnormal, such as when the discharge cut-off voltage is lower than a preset threshold, the microcontroller unit controls the power switch 60 to open.

[0110] In addition, as described above, the shunt switch 50 is electrically connected to the microcontroller unit (MCU) and is also controlled by the microcontroller unit to selectively open or close.

[0111] In another feasible embodiment, specifically referring to Figure 4 and Figure 5 as shown, the battery pack 10 includes a built-in discharge switch 102 and a BMS protection board 101. When the information of the battery pack 10 is abnormal, such as when the discharge cut-off voltage is lower than a preset threshold, the BMS protection board 101 controls the discharge switch 102 to open. In this way, the battery pack will have a built-in protection function. When the information of the battery pack 10 itself is abnormal, the BMS protection board 101 will cut off the output of the battery pack 10 by opening the discharge switch 102. In particular, when the discharge cut-off voltage of the battery pack 10 is lower than a preset threshold, the BMS protection board 101 controls the discharge switch 102 to open to avoid over-discharge.

[0112] At this time, a power switch 60 can be further configured on the transmission circuit. When the BMS protection board 101 of the battery pack 10 controls the discharge switch 102 to open, the microcontroller unit (MCU) simultaneously controls the power switch 60 to open, forming multiple protections for the battery pack parallel connection circuit 100.

[0113] Furthermore, the voltage conversion module 30 is a DC / DC module. More preferably, the DC / DC module is a bidirectional DC / DC module. In this way, the battery pack 10 can also be reversely charged through the bidirectional DC / DC module.

[0114] In another specific embodiment, specifically referring to Figure 6 as shown, the battery pack parallel connection circuit 100 includes:

[0115] N battery packs, each of which is adapted to output direct current, where N > 2;

[0116] transmission circuits provided in one-to-one correspondence with the battery packs;

[0117] A voltage conversion module is configured on each transmission circuit;

[0118] The battery packs are respectively electrically connected to the DC bus 40 through the voltage conversion modules corresponding to them; among them,

[0119] A connection node N is configured between the output of the battery pack and the input of the voltage conversion module on each transmission circuit,

[0120] A shunt switch is arranged between the connection nodes N. When it is detected that a certain transmission circuit is disconnected, one of the shunt switches connected to both sides of the connection node N on the disconnected transmission circuit is controlled to disconnect and the other is closed according to a preset control logic, and the rest of the shunt switches are all disconnected;

[0121] When a transmission circuit is connected to the closed shunt switch, the direct current output by the corresponding battery pack is shunted by the closed shunt switch. One path flows through the voltage conversion module on the original transmission circuit to the DC bus 40, and the other path flows through the voltage conversion module on the disconnected transmission circuit through the closed shunt switch to the DC bus.

[0122] Among them, the above preset control logic includes:

[0123] Compare the voltages of the battery packs on the transmission circuits connected to the other ends of the shunt switches on both sides of the connection node N;

[0124] The shunt switch connected to the side of the battery pack with a higher voltage is closed, and the shunt switch connected to the side of the battery pack with a lower voltage is disconnected.

[0125] Refer to Figure 7 As shown, taking the battery pack parallel connection circuit 100 with three battery packs 10 as an example. The battery pack parallel connection circuit 100 includes:

[0126] The first battery pack 10a, the corresponding first transmission circuit 20a and the first voltage conversion module 30a;

[0127] The second battery pack 10b, the corresponding second transmission circuit 20b and the second voltage conversion module 30b;

[0128] The third battery pack 10c, the corresponding third transmission circuit 20c and the third voltage conversion module 30c;

[0129] Each battery pack is respectively electrically connected to the DC bus 40 through the voltage conversion module corresponding to it; among them,

[0130] A first connection node N1 is configured between the output of the first battery pack 10a and the input of the first voltage conversion module 30a on the first transmission circuit 20a;

[0131] The second transmission circuit 20b is configured with a second connection node N2 between the output of the second battery pack 10b and the input of the second voltage conversion module 30b;

[0132] The third transmission circuit 20c is configured with a third connection node N3 between the output of the third battery pack 10c and the input of the third voltage conversion module 30c;

[0133] A first shunt switch 50a is provided between the first connection node N1 and the second connection node N2, a second shunt switch 50b is provided between the second connection node N2 and the third connection node N3, and a third shunt switch 50c is provided between the third connection node N3 and the first connection node N1.

[0134] When it is detected that the first transmission circuit 20a is disconnected, one of the shunt switches connected to both sides of the first connection node N1 on the first transmission circuit 20a, that is, either the third shunt switch 50c or the first shunt switch 50a, is disconnected and the other is closed, and the second shunt switch 50b is disconnected;

[0135] The second transmission circuit 20b or the third transmission circuit 20c is connected to the closed shunt switch, and the direct current output by the corresponding second battery pack 10b or third battery pack 10c is shunted by the closed shunt switch. One path flows through the voltage conversion module on the original transmission circuit to the DC bus 40, and the other path flows through the voltage conversion module on the disconnected transmission circuit through the closed shunt switch to the DC bus 40.

[0136] Specifically, taking the case where the third shunt switch 50c is controlled to be disconnected, the first shunt switch 50a is closed, and the second shunt switch 50b is disconnected as an example. At this time, the second transmission circuit 20b is connected to the closed shunt switch, and the direct current output by the corresponding second battery pack 10b is shunted by the closed first shunt switch 50a. One path flows through the original transmission circuit, that is, the second voltage conversion module 30b on the second transmission circuit 20b to the DC bus 40, and the other path flows through the closed first shunt switch 50a through the disconnected transmission circuit, that is, the first voltage conversion module 30a on the first transmission circuit 20a to the DC bus 40, while the third battery pack 10c on the third transmission circuit 20c reaches the DC bus 40 through the corresponding third voltage conversion module 30c.

[0137] Further, continue to refer to Figure 7 As shown, the shunt switches on both sides of the first connection node N1 are the first shunt switch 50a and the third shunt switch 50c respectively. The other end of the first shunt switch 50a is connected to the second transmission circuit 20b, and the other end of the third shunt switch 50c is connected to the third transmission circuit 20c.

[0138] In the above preset control logic, compare the voltages of the battery packs 10 on the transmission circuits 20 connected to the other ends of the shunt switches on both sides of the first connection node N1, that is, compare the voltages of the second battery pack 10b and the third battery pack 10c.

[0139] It is set that the voltage of the second battery pack 10b is higher than that of the third battery pack 10c. Then, the first shunt switch 50a connected to the second battery pack 10b is closed, the third shunt switch 50c is opened, and the remaining second shunt switches 50b are opened. At this time, the second transmission circuit 20b is connected to the closed first shunt switch 50a. The direct current output by the corresponding second battery pack 10b is shunted by the closed first shunt switch 50a. One path flows through the original transmission circuit, that is, the second voltage conversion module 30b on the second transmission circuit 20b to the DC bus 40, and the other path flows through the closed first shunt switch 50a through the opened transmission circuit, that is, the first voltage conversion module 30a on the first transmission circuit 20a to the DC bus 40, while the third battery pack 10c on the third transmission circuit 20c reaches the DC bus 40 through the corresponding third voltage conversion module 30c.

[0140] In addition, referring to Figure 8 As shown, when it is detected that only one transmission circuit 20 is conducting, control the shunt switches 50 on both sides of the connection node N on the conducting transmission circuit 20 to be closed, and the remaining shunt switches to be opened. The direct current output by the corresponding battery pack 10 is shunted by the closed shunt switch 50. One path flows through the voltage conversion module 30 on the original transmission circuit 20 to the DC bus 40, and the other two paths flow through the voltage conversion module 30 on the opened transmission circuit 20 through the closed shunt switch 50 to the DC bus 40.

[0141] Specifically, if only the second transmission circuit 20b corresponding to the second battery pack 10b is conducting, then control the first shunt switch 50a and the second shunt switch 50b on both sides of the second connection node N2 on the second transmission circuit 20b to be closed, and the third shunt switch 50c to be opened. The direct current output by the second battery pack 10b flows through the second voltage conversion module 30b on the original second transmission circuit 20b to the DC bus 40, and the other two paths respectively flow through the closed first shunt switch 50a and the second shunt switch 50b through the voltage conversion modules on the opened first transmission circuit 20a and the third transmission circuit 20c to the DC bus 40.

[0142] In addition to this, the present invention also relates to an energy storage device 200. Specifically, referring to Figure 9 and Figure 10 As shown, the energy storage device 200 includes:

[0143] The battery pack parallel connection circuit 100 as described above;

[0144] A DC / AC module 200a, which is electrically connected to the DC bus 40 and is adapted to invert the direct current converged and output by the DC bus 40 into an alternating current for output.

[0145] Further, the DC / AC module 200a is a bidirectional DC / AC module 200a.

[0146] Further, it further includes:

[0147] A connection port 200b, which is arranged in one-to-one correspondence with the battery pack 10 and is adapted to mechanically and electrically connect to the battery pack 10 and is detachably connected to the battery pack 10.

[0148] Further, when any battery pack 10 is connected to the connection port 200b, it is adapted to supply power to the first power device through the battery pack parallel connection circuit 100 and the DC / AC module 200a; when any battery pack 10 is detached and removed from the connection port 200b, the battery pack 10 is also adapted to supply power to the second power device.

[0149] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy storage device, characterized in that: include: a plurality of battery packs adapted to output direct current, including a first battery pack and a second battery pack; A connection port, which is arranged in one-to-one correspondence with the battery pack, is suitable for mechanically and electrically connecting to the battery pack, and is detachably connected to the battery pack; A DC / AC module, which is electrically connected to the DC bus and is suitable for converting the DC power output by the DC bus into AC power; When any of the battery packs is connected to the connection port, the battery pack parallel circuit and the DC / AC module are suitable for supplying power to the first power device; when any of the battery packs is removed from the connection port, the battery pack is also suitable for supplying power to the second power device; wherein, The battery pack parallel circuit comprises: A plurality of transmission circuits are arranged corresponding to the plurality of battery packs one by one; Each of the transmission circuits is provided with a voltage conversion module; The plurality of battery packs are electrically connected to the DC bus through the corresponding voltage conversion modules, and the first battery pack and the second battery pack correspond to the first voltage conversion module and the second voltage conversion module respectively; wherein, A shunt switch is also provided between the transmission circuits. When one of the transmission circuits is disconnected, the shunt switch connected to the disconnected transmission circuit is closed, and the DC power output by the battery pack on the other transmission circuit connected to the closed shunt switch is shunted through the closed shunt switch, one path flows through the voltage conversion module on the original transmission circuit to the DC bus, and the other path flows through the voltage conversion module on the disconnected transmission circuit to the DC bus through the closed shunt switch; Wherein, P1max≥P1+P2, P2max≥P1+P2, so that the output of the corresponding battery pack on a single transmission circuit is suitable for being shunted through the closed shunt switch to meet the maximum power output of multiple transmission circuits to supply power to the first power device, and another battery pack removed from the connection port supplies power to the second power device; P1max is the maximum output power of the first battery pack, and P2max is the maximum output power of the second battery pack; P1 is the maximum output power of the first voltage conversion module, and P2 is the maximum output power of the second voltage conversion module.

2. The energy storage device according to claim 1, characterized in that: A micro control unit is also included, and the micro control unit is suitable for controlling the shunt switch to selectively open or close.

3. The energy storage device according to claim 2, characterized in that: The shunt switch is a normally open switch.

4. The energy storage device according to claim 1, characterized in that: The voltage conversion module on each of the transmission circuits is suitable for outputting a consistent voltage or a voltage with a phase difference less than 0.1V.

5. The energy storage device according to claim 1, characterized in that: It also includes a power switch, which is placed between the battery pack and the voltage conversion module.

6. The energy storage device according to claim 5, characterized in that: The shunt switch and the power switch are respectively controlled by a micro control unit to selectively open or close.

7. The energy storage device according to claim 6, characterized in that: When the battery pack is not connected to the transmission circuit or when the discharge cut-off voltage of the battery pack is lower than a preset threshold, the micro control unit controls the power switch to be disconnected.

8. The energy storage device according to claim 1, 5, 6 or 7, characterized in that: The battery pack includes a built-in discharge switch and a BMS protection board. When the discharge cut-off voltage of the battery pack is lower than a preset threshold, the BMS protection board controls the discharge switch to be disconnected.

9. The energy storage device according to claim 1, characterized in that: The voltage conversion module is a DC / DC module or a bidirectional DC / DC module.

10. The energy storage device according to claim 1, characterized in that: The DC / AC module is a bidirectional DC / AC module.

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