A mistake proofing system and method for power battery series-parallel connection control

Abstract

The application provides a mistake-proof system and method for series-parallel connection control of power batteries, belongs to the technical field of circuit protection of power batteries, and is used for series-parallel connection control of two power batteries and comprises a battery management system, a series connection control module, a parallel connection control module, a series connection mistake-proof module and a parallel connection mistake-proof module. The battery management system controls the series connection of the two power batteries by outputting a control instruction to the series connection control module; the series connection control module controls the parallel connection mistake-proof module to disconnect the control loop of the battery management system and the parallel connection control module. The battery management system controls the parallel connection of the two power batteries by outputting a control instruction to the parallel connection control module; and the parallel connection control module controls the series connection mistake-proof module to disconnect the control loop of the battery management system and the series connection control module. The application prevents short circuit faults caused by circuit control errors during the series-parallel connection control of the two power batteries.

Description

Technical Field

[0001] This invention belongs to the field of power battery circuit protection technology. Specifically, this invention relates to a fault-prevention system and method for series-parallel control of power batteries. Background Technology

[0002] As the new energy vehicle industry accelerates its transition to 800V high-voltage platforms, power battery systems face an urgent need for multi-voltage platform compatibility. Current mainstream battery pack architectures generally suffer from platform rigidity: 400V battery systems struggle to meet the charging demands of 800V supercharging stations, while universal 800V solutions face challenges such as poor charging infrastructure compatibility and soaring component costs. The market urgently needs intelligent battery systems with flexible voltage switching capabilities to meet the development needs of cross-platform vehicles. Existing technologies, such as using relay arrays to achieve battery series-parallel topology reconfiguration, have been applied, but have revealed serious safety hazards in actual operating conditions. When the system switches between 400V and 800V modes, the high-voltage relay group may experience short-circuit faults due to erroneous closure of high-voltage relays during the execution of opening and closing sequence control.

[0003] Chinese Patent 220797835U provides an adjustable series-parallel switching device for a battery system, including a drive module, drive switches Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, and Q9. This adjustable series-parallel switching device enables the same battery system to operate simultaneously on two or more voltage platforms; it also allows for switching between series and parallel connections of two or more battery packs, achieving high-power charging and discharging.

[0004] Existing technology does not take into account the short-circuit fault caused by the miscontrol of the high-voltage relay in the series-parallel control circuit of two power batteries. Summary of the Invention

[0005] The present invention aims to provide a fault-prevention system and method for series-parallel control of power batteries, so as to solve the technical problem of short-circuit faults caused by the miscontrol of high-voltage relays in the series-parallel control circuit of two power batteries.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a fault-prevention system for series-parallel control of power batteries, used for the series-parallel control of two power batteries. It includes a battery management system, a series control module, a parallel control module, a series fault-prevention module, and a parallel fault-prevention module. The battery management system is connected to the series control module via the series fault-prevention module, and the battery management system is connected to the parallel control module via the parallel fault-prevention module. The output of the series control module is connected to the input of the parallel fault-prevention module, and the output of the parallel control module is connected to the input of the series fault-prevention module.

[0008] The series control module uses a series relay.

[0009] The parallel control module includes a first parallel relay and a second parallel relay.

[0010] The series error prevention module includes a first normally closed relay and a second normally closed relay.

[0011] One end of the power supply terminal of the first normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the series relay. The control terminal of the first normally closed relay is connected in parallel to the control terminal of the first parallel relay. One end of the power supply terminal of the second normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the series relay. The control terminal of the second normally closed relay is connected in parallel to the control terminal of the second parallel relay.

[0012] The parallel error prevention module includes a third normally closed relay and a fourth normally closed relay.

[0013] One end of the power supply terminal of the third normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the first parallel relay. The control terminal of the third normally closed relay is connected in parallel to the control terminal of the series relay. One end of the power supply terminal of the fourth normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the second parallel relay. The control terminal of the fourth normally closed relay is connected in parallel to the control terminal of the series relay.

[0014] This invention provides a method for a fault-proofing system for series-parallel control of power batteries, used for the series-parallel control of two power batteries:

[0015] The battery management system controls the two power batteries to be connected in series by outputting control commands to the series control module; the series control module controls the parallel error prevention module to disconnect the control loop between the battery management system and the parallel control module.

[0016] The battery management system controls the two power batteries to be connected in parallel by outputting control commands to the parallel control module; the parallel control module controls the series fault prevention module to disconnect the control loop between the battery management system and the series control module.

[0017] After the battery management system controls the series relay to close, the third normally closed relay in the parallel error prevention module disconnects the control circuit of the battery management system controlling the first parallel relay, and the fourth normally closed relay in the parallel error prevention module disconnects the control circuit of the battery management system controlling the second parallel relay.

[0018] After the battery management system controls the first parallel relay and the second parallel relay to close, the first normally closed relay in the series error prevention module disconnects the control circuit of the battery management system controlling the series relay, and the second normally closed relay in the series error prevention module disconnects the control circuit of the battery management system controlling the series relay.

[0019] The technical effects of this invention are as follows:

[0020] (1) This invention eliminates the risk of short circuits caused by erroneous series-parallel operation through hardware-level error-proof interlocking. When the battery management system controls the series relay to close, the control terminals of the third and fourth normally closed relays are energized because they are connected in parallel with the series relays, and their power supply terminals are disconnected, cutting off the control circuit of the battery management system to the first and second parallel relays. Even if the battery management system mistakenly issues a parallel connection command, the parallel relays cannot close, avoiding direct short circuit between the positive and negative terminals due to parallel operation when the high-voltage batteries are connected in series. When the battery management system controls the first and second parallel relays to close, the control terminals of the first and second normally closed relays are energized because they are connected in parallel with the parallel relays, and their power supply terminals are disconnected, cutting off the control circuit of the battery management system to the series relays. At this time, the series relays cannot be triggered, preventing short circuit between the positive and negative terminals of the power battery through the series circuit due to series operation when the two batteries are connected in parallel.

[0021] (2) The present invention sets independent fuses in series circuits and parallel positive and negative circuits. When the battery or relay fails and causes overcurrent, the fuse melts quickly, cutting off the fault circuit and avoiding safety accidents such as fires, which is in line with the safety design specifications of high voltage systems.

[0022] (3) The present invention uses a combination of high-voltage normally open relays and normally closed relays. Through the logical interlock of "power on control end - power on power supply end action", the fault circuit is forcibly blocked from the hardware level. Compared with simple software error prevention, it is more reliable and avoids safety hazards caused by program misjudgment.

[0023] (4) The system structure of the present invention is compact, and the layout of relays and fuses is clear. It can be directly integrated into the existing power battery management system without major changes to the vehicle circuit architecture, and is suitable for new energy vehicles with dual battery platforms.

[0024] (5) This invention is compatible with fault tolerance specifications for multi-topology battery systems, as well as the energy conversion efficiency requirements of power batteries. Under high surge impact, it can reliably block the fault current conduction path, thus improving the safety factor compared to traditional solutions. Attached Figure Description

[0025] This manual includes the following figures, which illustrate the following:

[0026] Figure 1 This is a logical structure block diagram of a fault-proofing system and method for series-parallel control of power batteries according to the present invention.

[0027] Figure 2 The circuit diagram of the series-parallel connection of the power battery is shown in the present invention as a fault-proofing system and method for series-parallel control of power batteries.

[0028] Figure 3 The connection relationship between the series-parallel relays and four normally closed relays is shown in the error-proofing system and method for series-parallel control of a power battery according to the present invention.

[0029] Figure 1 The components are labeled as follows: 1. Battery Management System; 2. Series Control Module; 3. Parallel Control Module; 4. Series Error Prevention Module; 5. Parallel Error Prevention Module. Detailed Implementation

[0030] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention, and to facilitate its implementation.

[0031] This invention provides a fault-prevention system for series-parallel control of power batteries, used for the series-parallel control of two power batteries. It includes a battery management system 1, a series control module 2, a parallel control module 3, a series fault-prevention module 4, and a parallel fault-prevention module 5. The battery management system 1 is connected to the series control module 2 through the series fault-prevention module 4, and the battery management system 1 is connected to the parallel control module 3 through the parallel fault-prevention module 5. The output terminal of the series control module 2 is connected to the input terminal of the parallel fault-prevention module 5, and the output terminal of the parallel control module 3 is connected to the input terminal of the series fault-prevention module 4.

[0032] The series control module 2 uses series relays. The parallel control module 3 includes a first parallel relay and a second parallel relay.

[0033] The series error-proofing module 4 includes a first normally closed relay and a second normally closed relay. One end of the power supply terminal of the first normally closed relay is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the series relay. The control terminal of the first normally closed relay is connected in parallel to the control terminal of the first parallel relay. One end of the power supply terminal of the second normally closed relay is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the series relay. The control terminal of the second normally closed relay is connected in parallel to the control terminal of the second parallel relay.

[0034] The parallel error-proofing module 5 includes a third normally closed relay and a fourth normally closed relay. One end of the power supply terminal of the third normally closed relay is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the first parallel relay. The control terminal of the third normally closed relay is connected in parallel to the control terminal of the series relay. One end of the power supply terminal of the fourth normally closed relay is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the second parallel relay. The control terminal of the fourth normally closed relay is connected in parallel to the control terminal of the series relay.

[0035] This invention provides a method for a fault-proofing system for series-parallel control of power batteries, used for the series-parallel control of two power batteries:

[0036] The battery management system 1 outputs control commands to the series control module 2 to control two power batteries to be connected in series; the series control module 2 controls the parallel error prevention module 5 to disconnect the control loop between the battery management system 1 and the parallel control module 3; the battery management system 1 outputs control commands to the parallel control module 3 to control two power batteries to be connected in parallel; the parallel control module 3 controls the series error prevention module to disconnect the control loop between the battery management system 1 and the series control module 2.

[0037] After the battery management system 1 controls the series relay to close, the third normally closed relay in the parallel error-proofing module 5 disconnects the control circuit of the battery management system 1 controlling the first parallel relay, and the fourth normally closed relay in the parallel error-proofing module 5 disconnects the control circuit of the battery management system 1 controlling the second parallel relay. After the battery management system 1 controls the first and second parallel relays to close, the first normally closed relay in the series error-proofing module 4 disconnects the control circuit of the battery management system 1 controlling the series relay, and the second normally closed relay in the series error-proofing module 4 disconnects the control circuit of the battery management system 1 controlling the series relay.

[0038] The following describes in detail a fault-prevention system for series and parallel control of power batteries according to the present invention.

[0039] The present invention discloses a fault-proofing system for series-parallel control of power batteries, which is used for series-parallel control of two power batteries. It includes a battery management system 1, a series control module 2, a parallel control module 3, a series fault-proofing module 4, and a parallel fault-proofing module 5. The battery management system (BMS) is used to control the series control module 2 and the parallel control module 3 to control the series-parallel connection of the two power batteries.

[0040] The series control module 2 uses a series relay to control the connection and disconnection of the two power batteries in series, thereby controlling the series connection of the two power batteries. Specifically, the control terminal of the series relay is connected to the output terminal of the battery management system 1. When the battery management system 1 outputs a control signal, the coil in the series controller is energized, the two power terminals of the series relay are connected, and the two power batteries are connected in series. In this embodiment of the invention, the voltage level of the two power batteries is 400V, and they form an 800V power supply after being connected in series.

[0041] The parallel control module 3 includes a first parallel relay and a second parallel relay, used to control the parallel connection of two power batteries. Specifically, the control terminals of the first and second parallel relays are respectively connected to the output terminals of the battery management system 1. The battery management system 1 controls the closing of the power supply terminals of the first and second parallel relays through their control terminals. When the power supply terminals of the first and second parallel relays are closed, a parallel circuit is formed, and the two power batteries are connected in parallel.

[0042] It should be noted that the series relay, the first parallel relay, and the second parallel relay are all high-voltage normally open relays. When there is a power input to the control terminal, the power supply terminal closes, and the circuit connected to the relay is completed. The control terminal is the coil terminal, and the power supply terminal is the contact terminal.

[0043] The series fault-prevention module 4 includes a first normally closed relay and a second normally closed relay, used to prevent the series control module 2 from being mistakenly controlled and causing a short circuit when two power batteries are connected in parallel. Specifically, after the battery management system 1 outputs control signals to the control terminals of the first and second parallel relays respectively, the control terminals of the first and second normally closed relays are connected in parallel. When the control terminals of the first and second normally closed relays receive control signals, they respectively control the power supply terminals of the first and second normally closed relays to open. Since the power supply terminals of the first and second normally closed relays are located in the control circuit of the battery management system 1 for the series relays, when two power batteries are connected in parallel, the series relays cannot be controlled to close by the battery management system 1, ensuring circuit safety. Either the first or second normally closed relay can disconnect the control circuit of the battery management system 1 for the series relays by working independently.

[0044] The parallel fault-prevention module 5 includes a third normally closed relay and a fourth normally closed relay, used to prevent the parallel control module 3 from being erroneously controlled and causing a short circuit when two power batteries are connected in series. Specifically, when the battery management system 1 outputs a control signal to the control terminal of the series relay, since the control terminals of the third and fourth relays are respectively connected in parallel to the control terminals of the series relay, when two power batteries are connected in series, the power terminals of the third and fourth relays are disconnected. The control circuits of the battery management system 1 to the first parallel relay and the second parallel relay are disconnected, and the power terminals of the first and second parallel relays cannot be closed, preventing a short circuit fault caused by the closing of the parallel relays when two power batteries are connected in parallel, thus protecting the circuit safety when two power batteries are connected in series.

[0045] The connection relationships of the present invention will now be described in detail with reference to the accompanying drawings.

[0046] The negative terminal of power battery S1 is connected to the positive terminal of power battery S2 via a series relay (K2). A fuse 3 is installed between power battery S1 and the series relay (K2). The negative terminal of power battery S1 is connected to the negative terminal of power battery S2 via a second parallel relay (K3). A fuse 2 is installed between the negative terminal of power battery S1 and the second parallel relay (K3). The positive terminal of power battery S1 is connected to the positive terminal of power battery S2 via a first parallel relay (K1). A fuse 1 is installed between the first parallel relay and power battery S2. The control terminals of the series relay (K2), the first parallel relay (K1), and the second parallel relay (K3) are respectively connected to the output terminals of the battery management system 1. One end of the power supply terminal of the first normally closed relay (K5) is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the series relay (K2). The control terminal of the first normally closed relay (K5) is connected in parallel to the control terminal of the first parallel relay (K1). One end of the power supply terminal of the second normally closed relay (K6) is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the series relay (K2). The control terminal of the second normally closed relay (K6) is connected in parallel to the control terminal of the second parallel relay (K3). One end of the power supply terminal of the third normally closed relay (K4) is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the first parallel relay (K1). The control terminal of the third normally closed relay (K4) is connected in parallel to the control terminal of the series relay (K2). One end of the power supply terminal of the fourth normally closed relay (K7) is connected to the output terminal of the battery management system 1, and the other end is connected to the control terminal of the second parallel relay (K3). The control terminal of the fourth normally closed relay (K7) is connected in parallel to the control terminal of the series relay (K2). Fuse 1, fuse 2 and fuse 3 are used to melt and protect the vehicle when the power battery fails.

[0047] The following describes in detail a method for a fault-proofing system for series and parallel control of power batteries according to the present invention.

[0048] The battery management system 1 controls two power batteries in series by outputting control commands to the series control module 2. Specifically, the battery management system 1 controls the series relay to close, and the two power batteries are connected in series to form an 800V power supply. After the series relay is closed, the power supply terminal of the third normally closed relay is disconnected because its control terminal is connected in parallel with the control terminal of the series relay, thus disconnecting the control circuit of the first parallel relay controlled by the battery management system 1. Similarly, the power supply terminal of the fourth normally closed relay is disconnected because its control terminal is connected in parallel with the control terminal of the series relay, thus disconnecting the control circuit of the second parallel relay controlled by the battery management system 1. At this time, even if the battery management system 1 mistakenly outputs control signals to the first and second parallel relays, the power supply terminals of the first and second parallel relays cannot be closed under control, preventing a short circuit fault caused by the closure of the first and second parallel relays.

[0049] The battery management system 1 outputs control commands to the parallel control module 3 to control the parallel connection of two power batteries. Specifically, the battery management system 1 outputs control signals to the control terminals of the first parallel relay and the second parallel relay, respectively. The power terminals of the first and second parallel relays close, forming a parallel circuit for the two power batteries. At this time, the operating voltage of the two parallel power batteries remains 400V. Since the control terminal of the first normally closed relay is connected in parallel with the control terminal of the second normally closed relay, and the control terminal of the second normally closed relay is connected in parallel with the control terminal of the second parallel relay, the power terminals of both the first and second normally closed relays are open, thus disconnecting the control circuit of the battery management system 1 for the series relays. Therefore, even if the battery management system 1 outputs control signals to the series relays, the series relays cannot be closed under control, protecting the two power batteries from short-circuit faults caused by accidental closure of the series relays when connected in parallel.

[0050] This invention eliminates the risk of short circuits caused by erroneous series-parallel connection operations through hardware-level error-proof interlocking. When the battery management system 1 controls the series relay to close, the control terminals of the third and fourth normally closed relays are energized because they are connected in parallel with the series relays, and their power supply terminals are disconnected, cutting off the control circuit of the battery management system 1 to the first and second parallel relays. Even if the battery management system 1 mistakenly issues a parallel connection command, the parallel relays cannot close, preventing direct short circuits between the positive and negative terminals due to parallel operation when the high-voltage batteries are connected in series. When the battery management system 1 controls the first and second parallel relays to close, the control terminals of the first and second normally closed relays are energized because they are connected in parallel with the parallel relays, and their power supply terminals are disconnected, cutting off the control circuit of the battery management system 1 to the series relays. At this time, the series relays cannot be triggered, preventing short circuits between the positive and negative terminals of the power battery through the series circuit due to series operation when the two batteries are connected in parallel.

[0051] This invention incorporates independent fuses in series circuits and parallel positive and negative circuits. When a battery or relay malfunctions and causes overcurrent, the fuse melts quickly, cutting off the faulty circuit and preventing safety accidents such as fires. This conforms to the safety design specifications for high-voltage systems.

[0052] This invention uses a combination of high-voltage normally open relays and normally closed relays. Through the logical interlock of "power on control end - power on end action", it forcibly blocks the faulty circuit from the hardware level. This is more reliable than simple software error prevention and avoids safety hazards caused by program misjudgment.

[0053] The system structure of this invention is compact, with a clear layout of relays and fuses. It can be directly integrated into the existing power battery management system 1 without significant changes to the vehicle's circuit architecture, and is suitable for new energy vehicles with dual-battery platforms.

[0054] This invention is compatible with fault tolerance specifications for multi-topology battery systems, while also meeting the energy conversion efficiency requirements of power batteries. Under high surge impacts, it can reliably block the fault current conduction path, thus improving the safety factor compared to traditional solutions.

[0055] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A fault-proofing system for series-parallel control of power batteries, used for series-parallel control of two power batteries, characterized in that: It includes a battery management system, a series control module, a parallel control module, a series error-proofing module, and a parallel error-proofing module. The battery management system is connected to the series control module through the series error-proofing module, and the battery management system is connected to the parallel control module through the parallel error-proofing module. The output terminal of the series control module is connected to the input terminal of the parallel error-proofing module, and the output terminal of the parallel control module is connected to the input terminal of the series error-proofing module.

2. The error-proofing system for series-parallel control of power batteries as described in claim 1, used for series-parallel control of two power batteries, characterized in that: The series control module uses a series relay.

3. The error-proofing system for series-parallel control of power batteries as described in claim 1, used for series-parallel control of two power batteries, characterized in that: The parallel control module includes a first parallel relay and a second parallel relay.

4. A fault-proofing system for series-parallel control of power batteries as described in claim 2, used for series-parallel control of two power batteries, characterized in that: The series error prevention module includes a first normally closed relay and a second normally closed relay.

5. A fault-proofing system for series-parallel control of power batteries as described in claim 4, used for series-parallel control of two power batteries, characterized in that: One end of the power supply terminal of the first normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the series relay. The control terminal of the first normally closed relay is connected in parallel to the control terminal of the first parallel relay. One end of the power supply terminal of the second normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the series relay. The control terminal of the second normally closed relay is connected in parallel to the control terminal of the second parallel relay.

6. A fault-proofing system for series-parallel control of power batteries as described in claim 2, used for series-parallel control of two power batteries, characterized in that: The parallel error prevention module includes a third normally closed relay and a fourth normally closed relay.

7. A fault-proofing system for series-parallel control of power batteries as described in claim 6, used for series-parallel control of two power batteries, characterized in that: One end of the power supply terminal of the third normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the first parallel relay. The control terminal of the third normally closed relay is connected in parallel to the control terminal of the series relay. One end of the power supply terminal of the fourth normally closed relay is connected to the output terminal of the battery management system, and the other end is connected to the control terminal of the second parallel relay. The control terminal of the fourth normally closed relay is connected in parallel to the control terminal of the series relay.

8. A method for a fault-proofing system for series-parallel control of power batteries as described in any one of claims 1-7, used for series-parallel control of two power batteries, characterized in that: The battery management system controls the two power batteries to be connected in series by outputting control commands to the series control module; the series control module controls the parallel error prevention module to disconnect the control loop between the battery management system and the parallel control module. The battery management system controls the two power batteries to be connected in parallel by outputting control commands to the parallel control module; the parallel control module controls the series fault prevention module to disconnect the control loop between the battery management system and the series control module.

9. A method for a fault-proofing system for series-parallel control of power batteries as described in claim 8, used for series-parallel control of two power batteries, characterized in that: After the battery management system controls the series relay to close, the third normally closed relay in the parallel error prevention module disconnects the control circuit of the battery management system controlling the first parallel relay, and the fourth normally closed relay in the parallel error prevention module disconnects the control circuit of the battery management system controlling the second parallel relay.

10. A method for a fault-proofing system for series-parallel control of power batteries as described in claim 8, used for series-parallel control of two power batteries, characterized in that: After the battery management system controls the first parallel relay and the second parallel relay to close, the first normally closed relay in the series error prevention module disconnects the control circuit of the battery management system controlling the series relay, and the second normally closed relay in the series error prevention module disconnects the control circuit of the battery management system controlling the series relay.

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