A high voltage dc input battery cell testing system and method

Abstract

This invention relates to a high-voltage DC input battery cell testing system and method. The battery cell testing system includes a high-voltage DC input bus for receiving high-voltage DC power; multiple isolation conversion modules, each with its input terminal connected to the high-voltage DC input bus, for isolating and converting the high-voltage DC power supply and outputting low-voltage DC power; multiple low-voltage DC buses, each connected to the output terminal of at least one isolation conversion module, for forming a distributed low-voltage DC power supply path; multiple battery cell testing modules, each connected to a low-voltage DC bus, for performing charge-discharge tests on the tested battery cell; a high-voltage energy storage module connected to the high-voltage DC input bus for storing and releasing energy from the high-voltage DC power supply; and multiple low-voltage energy storage modules, each connected to a low-voltage DC bus via a switch, for storing and releasing energy on the corresponding low-voltage DC bus.

Description

Technical Field

[0001] This invention relates to the field of battery cell testing technology, and in particular to a battery cell testing system and method with high-voltage DC input. Background Technology

[0002] As the basic unit of battery systems, battery cells are widely used in new energy fields such as electric vehicles and electrochemical energy storage. To ensure the performance consistency and safety of battery cells in actual use, it is usually necessary to conduct charge and discharge performance tests on the cells during the research and development and production process. Therefore, the structure and power supply method of the battery cell testing system directly affect the testing efficiency, system losses, and construction costs.

[0003] Existing cell testing systems mostly use the AC mains as the input power source, which is then converted from AC to DC to form a medium-to-low voltage DC bus. This DC bus then supplies power to each test channel via isolation and DC-DC conversion units. When the number of channels is large, this approach results in a relatively low DC-side voltage level, leading to a large supply current, higher line losses, and higher wiring costs. Simultaneously, the energy exchange path between test channels is long, limiting the overall energy utilization efficiency of the system. Furthermore, existing solutions have limited adaptability to high-voltage DC input power sources in terms of system architecture, making them difficult to directly apply to testing scenarios powered by high-voltage DC buses. Summary of the Invention

[0004] To address the above technical problems, this invention proposes a high-voltage DC input cell testing system, the system comprising:

[0005] High-voltage DC input bus, used to receive DC high-voltage power;

[0006] Multiple isolation conversion modules are provided, with their input terminals connected to the high-voltage DC input bus, for isolating and converting the high-voltage DC power supply and outputting low-voltage DC power.

[0007] Multiple low-voltage DC buses are connected to the output of at least one isolation converter module to form a distributed low-voltage DC power supply path.

[0008] Multiple cell testing modules are provided, each connected to a corresponding low-voltage DC bus, for performing charge-discharge tests on the cell under test.

[0009] The high-voltage energy storage module is connected to the high-voltage DC input bus via a non-isolated conversion module and is used to store and release energy from the DC high-voltage power supply.

[0010] Multiple low-voltage energy storage modules are connected to the low-voltage DC bus via switches to store and release electrical energy on the corresponding low-voltage DC bus.

[0011] Optionally, each of the isolation transformation modules includes a high-voltage side transformation unit, an isolation transformer unit, and a low-voltage side transformation unit connected in sequence;

[0012] The high-voltage side conversion unit is connected to the high-voltage DC input bus and is used to convert the input high-voltage DC power.

[0013] The isolation transformer unit is used to achieve electrical isolation between the high-voltage side and the low-voltage side;

[0014] The low-voltage side conversion unit is connected to the low-voltage DC bus and is used to output low-voltage DC power.

[0015] Optionally, the high-voltage side conversion unit includes multiple power conversion bridge arms;

[0016] The isolation transformer unit includes multiple transformer primary windings that correspond to the multiple power conversion bridge arms respectively;

[0017] The multiple power conversion bridge arms are connected in series to divide the voltage of the high-voltage DC input bus.

[0018] Optionally, each of the cell testing modules includes multiple DC-DC converters, multiple cells under test, and a DC-DC converter controller;

[0019] The input terminal of each DC-DC converter unit is connected to the corresponding low-voltage DC bus, and the output terminal is connected to the corresponding battery cell under test, for regulating the voltage and current of the battery cell under test during the charging and discharging process.

[0020] The DC-DC converter controller is connected to the plurality of DC-DC converter units respectively, and is used to control the operating status of the plurality of DC-DC converter units.

[0021] Optionally, the system further includes:

[0022] A centralized energy storage controller, connected to the high-voltage energy storage module, is used to control the charging and discharging process of the high-voltage energy storage module;

[0023] A distributed energy storage controller, connected to the low-voltage energy storage module, is used to control the charging and discharging process of the low-voltage energy storage module.

[0024] Optionally, the system further includes:

[0025] An isolation converter controller, connected to the isolation converter module, is used to control the operating status of the isolation converter module.

[0026] Optionally, the system further includes:

[0027] The main controller is communicatively connected to the centralized energy storage controller, the distributed energy storage controller, and the isolated conversion controller, and is used to coordinate and control the centralized energy storage controller, the distributed energy storage controller, and the isolated conversion controller.

[0028] Optionally, the high-voltage energy storage module is connected to the high-voltage side of the isolation conversion module through the high-voltage DC input bus, so that the high-voltage energy storage module can provide energy to the isolation conversion module through the high-voltage DC input bus when in discharge state, and output electrical energy to the low-voltage DC bus through the isolation conversion module, thereby forming a first energy transmission loop from the high-voltage energy storage module to the low-voltage DC bus through the high-voltage DC input bus and the isolation conversion module.

[0029] Optionally, the low-voltage energy storage module is connected to the corresponding low-voltage DC bus, enabling the low-voltage energy storage module to exchange energy with the low-voltage DC bus during charging and discharging, and working together with the electrical energy output to the low-voltage DC bus by the isolation conversion module to form a second energy transmission loop with multiple energy sources on the low-voltage side.

[0030] Secondly, a method for testing battery cells with high-voltage DC input includes the following steps:

[0031] It receives DC high-voltage power and supplies power through the high-voltage DC input bus;

[0032] The DC high-voltage power supply is isolated and converted through multiple isolation conversion modules to output low-voltage DC power.

[0033] The low-voltage DC power is output to multiple low-voltage DC buses to form a distributed low-voltage DC power supply path.

[0034] The low-voltage DC bus supplies power to multiple cell testing modules to perform charging and discharging tests on the cells under test.

[0035] The high-voltage DC input cell testing system of this invention uses a high-voltage DC input bus as a unified power supply inlet at the system level, and directly converts the high-voltage DC power into low-voltage DC power through multiple isolated conversion modules, and then outputs it to multiple low-voltage DC buses to form a distributed low-voltage DC power supply path. This allows each cell testing module to draw power from the nearest source to complete charge and discharge tests. In this way, while meeting the requirements of parallel testing of multi-channel cells, it reduces the low-voltage side power supply current, shortens the power supply loop length, reduces line loss and wiring costs, and improves the overall power supply efficiency and structural adaptability of the system in large-scale testing scenarios.

[0036] Furthermore, by installing high-voltage energy storage modules on the high-voltage DC input bus and configuring low-voltage energy storage modules on each low-voltage DC bus side, the system possesses energy storage and regulation capabilities on both the high-voltage and low-voltage sides. This allows for tiered buffering and allocation of energy during power fluctuations or changes in test load. On one hand, the high-voltage energy storage modules enable centralized energy regulation at the system level; on the other hand, the low-voltage energy storage modules provide local energy compensation and stable power supply on their respective low-voltage bus sides, ensuring a more stable power environment for each cell testing module during operation. This forms a power supply structure combining centralized high-voltage energy storage and distributed low-voltage energy storage, which is beneficial for improving the overall energy utilization efficiency and operational stability of the system, and enhancing the adaptability of the cell testing system under complex testing conditions.

[0037] Furthermore, through centralized and coordinated control of the isolation conversion module, high-voltage side voltage sharing, stable operation of the isolation conversion process, and coordinated cooperation among multiple low-voltage power supply paths are achieved. This further improves the system's adaptability to load fluctuations and changes in multi-channel operating conditions, enhances the flexibility and stability of energy utilization during testing, and improves the overall operational reliability and engineering application value of the cell testing system. Attached Figure Description

[0038] Figure 1 A block diagram of a high-voltage DC input cell testing system according to an embodiment of the present invention is shown;

[0039] Figure 2 A block diagram of a high-voltage DC input cell testing system according to another embodiment of the present invention is shown;

[0040] Figure 3 A detailed block diagram of a cell testing module according to an embodiment of the present invention is shown;

[0041] Figure 4 A circuit topology diagram of a high-voltage DC input cell testing system according to an embodiment of the present invention is shown;

[0042] Figure 5 A schematic diagram of the energy flow of a high-voltage DC input cell testing system according to an embodiment of the present invention is shown;

[0043] Figure 6 A flowchart of a high-voltage DC input cell testing method according to an embodiment of the present invention is shown. Detailed Implementation

[0044] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the present invention and not for limiting the present invention. Furthermore, it should be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all structures. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0045] The terms "comprising" and "having," and any variations thereof, used in this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] Unlike existing cell testing systems that generally use AC power grid as the system input, this patent fundamentally adjusts the input form at the system power supply architecture level, directly using high-voltage direct current (HVDC) as the unified input source. The HVDC power is then distributed to each testing unit after isolation and transformation. This technical approach no longer relies on AC input and its corresponding rectification and distribution system, but instead constructs an overall power supply and testing architecture around the HVDC bus, resulting in substantial changes to the system's energy transmission path, transformation levels, and structural organization.

[0048] This design approach, which uses direct high-voltage DC input to the cell testing system, breaks through the long-standing technical convention of designing cell testing equipment based on AC input. It enables the cell testing system to directly adapt to DC bus power supply environments and reorganizes energy conversion and distribution relationships at the system level, thus providing a new technical path for reducing power loss, optimizing system structure, and expanding application scenarios. This change is not a simple replacement of existing solutions, but a complete reconstruction of the power supply mode and system architecture of the cell testing system.

[0049] Figure 1 A block diagram of a high-voltage DC input cell testing system according to an embodiment of the present invention is shown. Figure 1As shown, the high-voltage DC input cell testing system includes a high-voltage DC input bus, multiple isolation conversion modules 10, multiple low-voltage DC buses, multiple cell testing modules 20, a high-voltage energy storage module 30, a non-isolated conversion module 40, and multiple low-voltage energy storage modules 50. The high-voltage DC input bus receives high-voltage DC power. The input terminals of the multiple isolation conversion modules 10 are connected to the high-voltage DC input bus, used to isolate and convert the high-voltage DC power and output low-voltage DC energy. The multiple low-voltage DC buses are connected to the output terminals of at least one isolation conversion module 10, forming a distributed low-voltage DC power supply path. The multiple cell testing modules 20 are connected to the low-voltage DC buses, used to perform charge and discharge tests on the tested cell 22. The high-voltage energy storage module 30 is connected to the high-voltage DC input bus through the non-isolated conversion module 40, used to store and release energy from the high-voltage DC power. The multiple low-voltage energy storage modules 50 are connected to the low-voltage DC buses through switches, used to store and release energy on the corresponding low-voltage DC buses.

[0050] In this embodiment, by installing a high-voltage energy storage module 30 on the high-voltage DC input bus, the system possesses energy buffering and regulation capabilities on the high-voltage DC side. This enables centralized management and scheduling of electrical energy on the high-voltage side when external DC power fluctuates or load conditions change. This structure, while maintaining the high-voltage DC direct input architecture, further enhances the stability and adaptability of the system's power supply, thus better meeting the needs for continuous and flexible energy supply under different testing conditions.

[0051] Meanwhile, in this embodiment, multiple low-voltage energy storage modules 50 are set on each low-voltage DC bus, forming a structure in which multiple energy storage modules work collaboratively on the same low-voltage DC bus. Each low-voltage energy storage module 50 can participate in energy storage and release, and respond to different energy flow directions when different cell test modules 20 are in charging or discharging states, thereby distributing and locally allocating energy on the same low-voltage DC bus among multiple energy storage modules. Compared with setting only a single low-voltage energy storage module 50, this structure can simultaneously handle differentiated energy changes from multiple test channels, avoiding the energy response limitation of a single energy storage module under multi-channel parallel operation, making low-voltage side energy interaction more dispersed and completed locally, thereby further shortening the energy flow path and enhancing the system's adaptability under multi-channel synchronous testing conditions.

[0052] According to the above embodiments, by using a high-voltage DC input bus as a unified power supply entry point at the system level, and directly converting the high-voltage DC power into low-voltage DC power through multiple isolation conversion modules 10, and then outputting it to multiple low-voltage DC buses to form a distributed low-voltage DC power supply path, each cell test module 20 can draw power from nearby to complete the charge and discharge test. This not only meets the requirements of parallel testing of multi-channel cells, but also reduces the low-voltage side power supply current, shortens the power supply loop length, reduces line loss and wiring costs, and improves the overall power supply efficiency and structural adaptability of the system in large-scale testing scenarios.

[0053] Furthermore, by installing a high-voltage energy storage module 30 on the high-voltage DC input bus and configuring low-voltage energy storage modules 50 on each low-voltage DC bus side, the system possesses energy storage and regulation capabilities on both the high-voltage and low-voltage sides. This allows for graded buffering and allocation of energy during power fluctuations or changes in test load. On one hand, the high-voltage energy storage module 30 enables centralized energy regulation at the system level; on the other hand, the low-voltage energy storage module 50 provides local energy compensation and stable power supply on the corresponding low-voltage bus side, ensuring a more stable power environment for each cell testing module 20 during operation. This forms a power supply structure combining centralized high-voltage energy storage and distributed low-voltage energy storage, which is beneficial for improving the overall energy utilization efficiency and operational stability of the system, and enhancing the adaptability of the cell testing system under complex testing conditions.

[0054] Figure 2 A block diagram of a high-voltage DC input cell testing system according to another embodiment of the present invention is shown. Figure 2 As shown, the cell testing system also includes a centralized energy storage controller 60. The centralized energy storage controller 60 is connected to both the non-isolated conversion module 40 and the high-voltage energy storage module 30, and is used to control the charging and discharging processes of the high-voltage energy storage module 30.

[0055] In this embodiment, a centralized energy storage controller 60 is set up to uniformly manage and coordinate the charging and discharging behavior of the high-voltage energy storage module 30, enabling the high-voltage energy storage module 30 to participate in energy dispatch according to a predetermined strategy during system operation. This allows for effective control of the energy flow and power level on the high-voltage side under different operating conditions, avoiding the impact of disordered charging and discharging on the system, thereby improving the utilization efficiency of the high-voltage energy storage module 30 and contributing to ensuring the overall safety and stability of the cell testing system.

[0056] In one embodiment, reference Figure 2 The cell testing system also includes a distributed energy storage controller 70. The distributed energy storage controller 70 is connected to multiple corresponding low-voltage energy storage modules 50 and is used to control the charging and discharging processes of the low-voltage energy storage modules 50.

[0057] In this embodiment, each distributed energy storage controller 70 corresponds to a low-voltage DC bus and is simultaneously connected to multiple low-voltage energy storage modules 50 on that low-voltage DC bus. By controlling the charging and discharging processes of each low-voltage energy storage module 50 separately, each energy storage module can participate in energy storage and release according to different energy states, thereby achieving energy distribution and coordinated regulation among multiple energy storage modules within the same low-voltage DC bus range. Therefore, when multiple cell test channels are operating in parallel, a decentralized response can be provided to energy changes in different channels, avoiding the energy processing capacity limitations caused by single energy storage regulation. This allows for more refined and localized low-voltage side energy allocation, thereby improving the system's energy regulation capability and operational stability under complex multi-channel test conditions.

[0058] In one embodiment, reference Figure 2 The cell testing system also includes an isolation converter controller 80. The isolation converter controller 80 is connected to the isolation converter module 10 and is used to control the operating status of the isolation converter module 10.

[0059] In this embodiment, by setting up an isolation conversion controller 80, the operation process of the isolation conversion module 10 is uniformly monitored and adjusted, enabling the isolation conversion module 10 to maintain stable operation under different operating conditions. Therefore, the isolation conversion process can be adaptively controlled according to the system operating status, ensuring reliable and controllable energy transmission between the isolated and non-isolated sides, thereby improving the safety and overall operational stability of the cell testing system.

[0060] In one embodiment, reference Figure 2 The cell testing system also includes a main controller 90. The main controller 90 is communicatively connected to the centralized energy storage controller 60, the distributed energy storage controller 70, and the isolation converter controller 80, and is used to coordinate and control the centralized energy storage controller 60, the distributed energy storage controller 70, and the isolation converter controller 80.

[0061] In this embodiment, a central controller 90 is introduced to coordinate the control behaviors of the centralized energy storage controller 60, the distributed energy storage controller 70, and the isolation conversion controller 80, enabling the functional modules to form a cooperative control relationship during system operation. This allows for orderly linkage between energy storage scheduling and isolation conversion control under different test conditions, avoiding conflicts or resource waste caused by independent operation of each control unit, thereby improving the overall coordination, stability, and control efficiency of the cell testing system.

[0062] Figure 3 A detailed block diagram of a cell testing module 20 according to an embodiment of the present invention is shown. Figure 3As shown, each cell testing module 20 includes multiple DC-DC converter units 21, multiple cells under test 22, and a DC-DC converter controller 23. The input terminal of each DC-DC converter unit 21 is connected to the corresponding low-voltage DC bus, and the output terminal is connected to the corresponding cell under test 22, used for voltage and current regulation during the charging and discharging processes of the cell under test 22. The DC-DC converter controller 23 is connected to multiple DC-DC converter units 21 respectively, used for controlling the operating status of the multiple DC-DC converter units 21.

[0063] In this embodiment, each cell testing module 20 is equipped with a DC-DC converter controller 23, which connects to and controls multiple DC-DC converter units 21. Each DC-DC converter unit 21 corresponds to a different cell under test 22, achieving a structure that combines centralized control and independent adjustment of multiple channels within the same cell testing module 20. Through this configuration, the DC-DC converter controller 23 can control the operating state of the corresponding DC-DC converter unit 21 according to the test status of each cell under test 22. This allows different cells under test 22 to adjust their voltage and current according to their respective test requirements during charging or discharging. Compared to methods relying solely on a single control or completely independent control of each channel, this structure ensures the independence of the testing process for each cell under test 22 while achieving unified and coordinated control of multiple channels within the module. This avoids mutual interference or inconsistent control during multi-channel operation, enabling the cell testing module 20 to have higher control accuracy and operational consistency under multi-cell parallel testing conditions, thereby improving the adaptability and reliability of the overall testing system.

[0064] According to the above embodiment, the input source of this system is a 1500V DC power supply. On the input side, a high-power non-isolated DC-DC converter is connected to a high-voltage centralized energy storage system to achieve charging and discharging control of the high-voltage energy storage. Depending on the actual application requirements, the high-voltage centralized energy storage system can also be directly connected to the input source and used as a primary energy storage unit in the system. The input source converts the 1500V DC power supply to a 15V DC power supply via a series-parallel series of low-power high-frequency isolated DC-DC converters. Each low-voltage bus connects to multiple low-voltage distributed energy storage modules, forming the secondary energy storage of the system.

[0065] Each low-voltage DC bus is connected to the tested battery cell 22 via multiple DC-DC converters. The tested battery cells 22 form an energy exchange loop through distributed energy storage and the low-voltage DC buses. This loop has a short path and low energy loss, which improves testing efficiency. A 1500V DC input source can simultaneously connect multiple series-parallel low-power high-frequency isolated DC-DC converters and the low-voltage distributed loop. Energy exchange between the low-voltage buses is achieved through the 1500V DC input source and high-voltage centralized energy storage after the isolation converters. The isolation converter only contains the isolated DC-DC conversion loop and does not include the AC-DC conversion stage, simplifying the loop and reducing losses. Furthermore, the high-voltage 1500V DC power supply has a high voltage and low current, requiring only two wires, resulting in low wiring costs and minimal path loss.

[0066] The secondary low-voltage distributed energy storage module provides energy output and feedback functions to the tested cells 22 on its respective low-voltage bus based on peak and off-peak electricity prices. The primary high-voltage centralized energy storage module provides energy output and feedback to the entire system based on peak and off-peak electricity prices. During off-peak electricity price periods, the primary energy storage reduces the energy level to the lower threshold. If a tested battery on a low-voltage bus is discharging and the corresponding secondary energy storage is fully charged, the excess energy can be fed back to the primary high-voltage centralized energy storage and distributed to other distributed energy storage units, thereby improving energy utilization efficiency during off-peak electricity price periods.

[0067] In this system, the high-voltage centralized energy storage, low-power isolated DC-DC converters, low-voltage distributed energy storage, and each DC-DC converter have independent control systems, allowing for individual control based on their specific characteristics. All controllers are connected to the central control system, uploading operational data for data storage and analysis. Simultaneously, the central control system possesses power scheduling capabilities, issuing control commands to each independent controller based on real-time power conditions and operational demands, thereby achieving coordinated operation of the entire system.

[0068] Figure 4 A circuit topology diagram of a high-voltage DC input cell testing system according to an embodiment of the present invention is shown. Figure 4 As shown, each isolation conversion module 10 includes a high-voltage side conversion unit, an isolation transformer unit, and a low-voltage side conversion unit connected in sequence. The high-voltage side conversion unit is connected to the high-voltage DC input bus and is used to convert the input high-voltage DC power. The isolation transformer unit is used to achieve electrical isolation between the high-voltage side and the low-voltage side. The low-voltage side conversion unit is connected to the low-voltage DC bus and is used to output low-voltage DC power.

[0069] In this embodiment, the three-stage structure of the isolation conversion module 10 achieves efficient energy conversion and safe isolation between the high-voltage input and the low-voltage DC bus. Specifically, the high-voltage conversion unit adjusts the DC high-voltage power to a state suitable for isolated transmission, the isolation transformer unit maintains energy transmission efficiency while ensuring electrical isolation, and the low-voltage conversion unit stably outputs energy to the low-voltage DC bus, providing a reliable power supply environment for the downstream low-voltage energy storage module 50 and the tested battery cell 22, thereby improving the operational safety and energy utilization efficiency of the battery cell testing system.

[0070] In one embodiment, reference Figure 4 The high-voltage side conversion unit includes multiple power conversion bridge arms. The isolation transformer unit includes multiple transformer primary windings corresponding to the multiple power conversion bridge arms. The multiple power conversion bridge arms are connected in series to divide the voltage of the high-voltage DC input bus.

[0071] In this embodiment, by connecting multiple power conversion arms of the high-voltage side conversion unit in series, the voltage of the high-voltage DC input bus is processed in stages, thereby reducing the voltage stress of individual arms. Each power conversion arm corresponds to the primary winding of the transformer in the isolation transformer unit, enabling each power path to be independently transmitted to the isolation side. This ensures electrical isolation while improving system reliability and energy conversion efficiency, and also simplifies the design of high-voltage side devices and reduces overall system losses.

[0072] According to the above embodiment, the primary terminal of the transformer in the isolated DC-DC converter withstands a DC input voltage of 1500V. Due to the high input voltage, conventional LLC isolation circuit schemes using power electronic devices with a withstand voltage of 1700V or lower cannot meet the voltage requirements. Furthermore, when the switching frequency is higher than 10kHz, the maximum withstand voltage of the devices is limited to 1700V. Therefore, traditional LLC isolation circuit schemes cannot be used directly. To reduce the device withstand voltage requirement while ensuring the required switching frequency, this embodiment employs a series connection of transformers within the high-voltage side bridge arm at the primary terminal of the transformer. By connecting the bridge arms in series, the actual voltage that the devices withstand is reduced from DC 1500V to DC 750V, allowing commonly used 1200V withstand voltage devices to meet the requirements, thereby improving equipment reliability and reducing costs. Simultaneously, the voltage ratio between the primary and secondary terminals of the transformer is reduced, lowering the difficulty of transformer manufacturing.

[0073] The low-voltage side output is 15V DC, characterized by low voltage and high current. To meet the high current output requirements, this embodiment employs a parallel connection between bridge arms on the low-voltage side. This parallel connection achieves high current, reducing the current at the secondary terminals of each transformer, thereby further reducing the difficulty and cost of transformer manufacturing. This isolated DC-DC converter can function as a modular unit, operating independently within the system and cooperating with other modules to achieve efficient and safe energy conversion between high and low voltage.

[0074] The primary high-voltage centralized energy storage unit is connected to a 1500V DC input source via a high-power non-isolated DC-DC converter. The converter employs a flying capacitor three-level DC topology, reducing the device operating voltage from 1500V to 750V, thus improving reliability and reducing cost. The energy storage battery is connected to the low-voltage side of the DC-DC converter, while the 1500V DC input source is connected to the high-voltage side. The energy storage battery can be configured with a maximum voltage of 1500V; when the battery voltage is below 1500V, it can be boosted to 1500V via the DC-DC converter, achieving high energy storage utilization and maintaining a stable 1500V voltage.

[0075] The secondary low-voltage distributed energy storage module is connected to a 15V DC distributed bus via a low-voltage, low-power buck-boost circuit. When the battery voltage is higher than the bus voltage, it operates by stepping down; when it is lower, it operates by stepping up. The battery configuration is flexible and can adapt to different testing requirements. Simultaneously, by maintaining a stable 15V distributed bus voltage, the accuracy of cell testing is improved.

[0076] This invention achieves efficient energy conversion, safe isolation, and flexible scheduling between high and low voltage by combining a primary centralized energy storage module on the high-voltage side with a secondary distributed energy storage module on the low-voltage side, and by using a modular design of an isolated DC-DC converter. This provides a reliable, stable, and high-precision energy supply environment for the cell testing system.

[0077] Figure 5 A schematic diagram of the energy flow of a high-voltage DC input cell testing system according to an embodiment of the present invention is shown. The energy flow diagram under one operating mode during system operation is shown below. Figure 5As shown. The high-voltage energy storage module 30 is connected to the high-voltage side of the isolation converter module 10 via the high-voltage DC input bus, enabling the high-voltage energy storage module 30 to provide energy to the isolation converter module 10 via the high-voltage DC input bus when in discharge mode, and to output electrical energy to the low-voltage DC bus via the isolation converter module 10. This forms the first energy transmission loop, namely path 1 and path 2, whereby the high-voltage energy storage module 30 supplies energy to the low-voltage DC bus via the high-voltage DC input bus and the isolation converter module 10. In this operating mode, the primary high-voltage centralized energy storage module is in discharge mode, providing energy to the DC 1500V input side and the primary terminal of the transformer of the high-frequency isolation DC-DC converter module. Its energy transmission path is shown in path 1. At this time, the energy storage battery voltage is less than or equal to DC 1500V. After receiving energy from the high-voltage side, the high-frequency isolation DC-DC converter module transmits the electrical energy to the secondary terminal of the transformer through isolation conversion and outputs low-voltage DC electrical energy to the DC 15V distributed bus. Its energy flow path is shown in path 2. Energy from the secondary terminals of multiple isolated DC-DC converter modules is combined on a 15V distributed DC bus to form a high-current output that meets the system requirements.

[0078] Simultaneously, the low-voltage energy storage module 50 is connected to the corresponding low-voltage DC bus, enabling energy exchange between the low-voltage energy storage module 50 and the low-voltage DC bus during charging and discharging. This, combined with the electrical energy output to the low-voltage DC bus by the isolation conversion module 10, forms a second energy transmission loop (path 3) on the low-voltage side. The secondary low-voltage distributed energy storage module provides energy to the DC 15V distributed bus, with the energy flow path shown in path 3. The low-voltage distributed energy storage module is regulated by its connected buck-boost converter module. When the energy storage battery voltage is higher or lower than the DC 15V bus voltage, the duty cycle can be adjusted to maintain the output voltage stably at DC 15V, thus ensuring the stability of the low-voltage bus voltage.

[0079] In other operating modes, the energy flow between the energy storage modules, isolated DC-DC converter modules, and DC bus in the system is in principle the same as in the above modes. Energy transmission and scheduling are carried out in accordance with the operating characteristics of each functional module, which will not be elaborated further here.

[0080] According to the above embodiments, the high-voltage DC input two-stage energy storage battery cell testing system proposed in this patent uses a 1500V DC bus as the input source. Through a system architecture combining high-frequency isolation conversion and staged energy storage, it achieves optimized design of the energy interaction circuit and power supply circuit of the battery cell 22 under test. The system adopts high-frequency isolation technology, which involves series connection of transformers within the high-voltage side bridge arm, series connection between bridge arms, and parallel connection between bridge arms on the low-voltage side, to convert the 1500V DC high voltage to a 15V DC low voltage to power the battery cell 22 under test. Centralized energy storage is configured on the high-voltage side, and distributed energy storage is configured on the low-voltage side. This effectively reduces loop current, shortens the energy transmission path, reduces line loss and wiring costs, and improves the overall energy conversion efficiency of the system while meeting the application requirements of direct input from the 1500V DC bus.

[0081] Furthermore, the tested cells 22 form a local energy interaction loop through distributed low-voltage energy storage and a low-voltage DC bus, enabling energy to be prioritized for balancing and distribution on the low-voltage side. This results in a simple loop structure, short path, and low energy loss. The isolation converter in the system only includes an isolation DC-DC conversion loop and does not involve AC-DC conversion, reducing the number of intermediate conversion stages and improving operating efficiency. Simultaneously, the 1500V DC side uses a high-voltage, low-current power supply method, requiring only two wires (positive and negative) to complete energy transmission, which helps reduce wiring complexity and path loss, further enhancing the system's engineering applicability in large-scale cell testing scenarios.

[0082] Figure 6 A flowchart illustrating a high-voltage DC input cell testing method according to an embodiment of the present invention is shown. Figure 6 As shown, the cell testing method for this high-voltage DC input includes:

[0083] Step S100: Receive DC high-voltage power supply and supply power through the high-voltage DC input bus.

[0084] Step S200: The DC high-voltage power supply is isolated and converted through multiple isolation conversion modules to output low-voltage DC power.

[0085] In step S300, low-voltage DC power is output to multiple low-voltage DC buses to form a distributed low-voltage DC power supply path.

[0086] In step S400, power is supplied to multiple cell test modules via a low-voltage DC bus to perform charging and discharging tests on the cells under test.

[0087] The specific implementation methods of each step in the above-mentioned high-voltage DC input cell testing method refer to the relevant content of the embodiment in the above-mentioned high-voltage DC input cell testing system, and will not be repeated here.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high-voltage DC input cell testing system, characterized in that, The system includes: High-voltage DC input bus, used to receive DC high-voltage power; Multiple isolation conversion modules are provided, with their input terminals connected to the high-voltage DC input bus, for isolating and converting the high-voltage DC power supply and outputting low-voltage DC power. Multiple low-voltage DC buses are connected to the output of at least one isolation converter module to form a distributed low-voltage DC power supply path. Multiple cell testing modules are provided, each connected to a corresponding low-voltage DC bus, for performing charge-discharge tests on the cell under test. The high-voltage energy storage module is connected to the high-voltage DC input bus via a non-isolated conversion module and is used to store and release energy from the DC high-voltage power supply. Multiple low-voltage energy storage modules are connected to the low-voltage DC bus via switches to store and release electrical energy on the corresponding low-voltage DC bus.

2. The high-voltage DC input cell testing system according to claim 1, characterized in that, Each of the isolation transformation modules includes a high-voltage side transformation unit, an isolation transformer unit, and a low-voltage side transformation unit connected in sequence. The high-voltage side conversion unit is connected to the high-voltage DC input bus and is used to convert the input high-voltage DC power. The isolation transformer unit is used to achieve electrical isolation between the high-voltage side and the low-voltage side; The low-voltage side conversion unit is connected to the low-voltage DC bus and is used to output low-voltage DC power.

3. The high-voltage DC input cell testing system according to claim 2, characterized in that, The high-voltage side conversion unit includes multiple power conversion bridge arms; The isolation transformer unit includes multiple transformer primary windings that correspond to the multiple power conversion bridge arms respectively; The multiple power conversion bridge arms are connected in series to divide the voltage of the high-voltage DC input bus.

4. The high-voltage DC input cell testing system according to claim 1, characterized in that, Each of the battery cell testing modules includes multiple DC-DC converter units, multiple battery cells under test, and a DC-DC converter controller; The input terminal of each DC-DC converter is connected to the corresponding low-voltage DC bus, and the output terminal is connected to the corresponding battery cell under test, for regulating the voltage and current of the battery cell under test during charging and discharging. The DC-DC converter controller is connected to the plurality of DC-DC converter units respectively, and is used to control the operating status of the plurality of DC-DC converter units.

5. The high-voltage DC input cell testing system according to claim 1, characterized in that, The system also includes: A centralized energy storage controller, connected to the high-voltage energy storage module, is used to control the charging and discharging process of the high-voltage energy storage module; A distributed energy storage controller, connected to the low-voltage energy storage module, is used to control the charging and discharging process of the low-voltage energy storage module.

6. The high-voltage DC input cell testing system according to claim 1, characterized in that, The system also includes: An isolation converter controller, connected to the isolation converter module, is used to control the operating status of the isolation converter module.

7. The high-voltage DC input cell testing system according to any one of claims 1-5, characterized in that, The system also includes: The main controller is communicatively connected to the centralized energy storage controller, the distributed energy storage controller, and the isolated conversion controller, and is used to coordinate and control the centralized energy storage controller, the distributed energy storage controller, and the isolated conversion controller.

8. The high-voltage DC input cell testing system according to claim 7, characterized in that, The high-voltage energy storage module is connected to the high-voltage side of the isolation conversion module through the high-voltage DC input bus, enabling the high-voltage energy storage module to provide energy to the isolation conversion module through the high-voltage DC input bus when in a discharge state, and to output electrical energy to the low-voltage DC bus through the isolation conversion module, thereby forming a first energy transmission loop in which the high-voltage energy storage module supplies energy to the low-voltage DC bus through the high-voltage DC input bus and the isolation conversion module.

9. The high-voltage DC input cell testing system according to claim 7, characterized in that, The low-voltage energy storage module is connected to the corresponding low-voltage DC bus, enabling energy exchange between the low-voltage energy storage module and the low-voltage DC bus during charging and discharging. Together with the electrical energy output to the low-voltage DC bus by the isolation conversion module, it forms a second energy transmission loop with multiple energy sources on the low-voltage side.

10. A cell testing method for a cell testing system with high-voltage DC input as described in any one of claims 1-9, characterized in that, Includes the following steps: It receives DC high-voltage power and supplies power through the high-voltage DC input bus; The DC high-voltage power supply is isolated and converted through multiple isolation conversion modules to output low-voltage DC power. The low-voltage DC power is output to multiple low-voltage DC buses to form a distributed low-voltage DC power supply path. The low-voltage DC bus supplies power to multiple cell testing modules to perform charging and discharging tests on the cells under test.

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