A high-power battery pack equalization device based on relay and intelligent heat dissipation

Abstract

The utility model is suitable for battery management technical field provides a kind of high-power battery pack equalizing device based on relay and intelligent heat dissipation, comprising: host computer and the discharging device for discharging the overvoltage electric core;For real-time monitoring electric core voltage and control discharging device work and with host computer data interaction mainboard;Wherein the discharging device includes discharging resistance and radiator, the utility model under the premise of keeping BMS relative simple circuit structure, realized the discharging equalization of more speed faster than traditional passive equalization current, significantly reduced the system cost of realizing active equalization, improved BMS reliability simultaneously.Compared with common active equalization scheme, avoid the EMI problem caused by high-frequency switch, save development time and cost.

Description

Technical Field

[0001] This utility model relates to the field of battery management technology, specifically a high-power battery pack balancing device based on relays and intelligent heat dissipation. Background Technology

[0002] In an era where energy storage batteries are becoming increasingly popular, variations in manufacturing processes, uneven system operating environments, and system design flaws can lead to inconsistent cell capacities within the same cluster or even the same battery unit over long-term operation. To maintain cell capacity consistency and improve battery system utilization, cells with excessively low or high voltages are balanced. Most mainstream battery management systems (BMS) employ passive balancing, where cells discharge through a direct connection to the BMS's own resistor. Due to the need to consider temperature rise in the circuit board and components, the balancing current is typically in the milliampere range, resulting in low efficiency. External balancing equipment is then required to balance the system, but such equipment is generally complex to assemble and expensive. This cost becomes even more prohibitive, especially for large-scale balancing operations.

[0003] Chinese patent CN203193337U discloses a power battery pack discharge equalization device, which includes an MCU control unit, a voltage acquisition unit, and an equalization circuit. The equalization circuit includes discharge resistors connected in series across the positive and negative terminals of each individual cell in the power battery pack, as well as corresponding on / off switches. The on / off switches select switching transistors, and the output of the MCU control unit controls each on / off switch connected to the equalization circuit. During use, the temperature rise and heat dissipation of the switching transistors need to be considered and addressed.

[0004] Chinese patent CN214707253U discloses an active equalization management system for battery packs, including a monitoring and control module, a main control module, an equalization control module, an energy storage module, and a boost module. This scheme charges the battery pack through the boost module. The other modules, besides the boost and energy storage modules, are similar to this device, all based on the fundamental framework of monitoring battery voltage. This scheme has complex circuitry, significantly increasing the difficulty of development and maintenance, and correspondingly increasing the system's cost and power consumption. Furthermore, the system algorithm and control logic are complex.

[0005] In summary, existing passive balancing solutions in battery management systems connect a power resistor and a MOSFET switch in parallel with each cell. When an excessively high voltage is detected in a cell, its corresponding switch is activated, allowing current to flow through the resistor and dissipating excess energy as heat until the voltage approaches that of the other cells. This solution severely limits the discharge speed, with discharge currents in the tens of milliamps range. For large-capacity battery packs or cases with significant inconsistencies, the balancing speed is very slow. Furthermore, the balancing components are prone to localized high temperature rise on small, enclosed circuit boards. Some passive balancing solutions externalize the balancing circuit and equip it with a fan for cooling, but this method of heat dissipation is singular, inefficient, and consumes a lot of power.

[0006] Existing active balancing solutions for BMS involve complex switching networks and DC-DC circuits, which significantly increases the cost of the circuit board. The increased power components and circuit board area also increase the size and weight. The increased number of components and frequent switching operations lead to more potential failure points. High-frequency switching operations will generate electromagnetic interference (EMI), requiring additional filtering and shielding designs. Algorithms for switching timing, energy transfer path management, and DC-DC control are much more complex than those for passive balancing, making software development and verification difficult.

[0007] Existing external balancing equipment, such as equalizers, is expensive and has limited functionality. Inconsistent cell capacity is common in energy storage sites. When passive balancing is too slow, balancing equipment needs to be used frequently. The more equipment used, the higher the cost. Users also need to spend more time and effort when using it. Additional maintenance costs will also be incurred when the equipment fails. In addition, existing external balancing equipment is basically controlled manually and lacks system interaction functions.

[0008] Therefore, in view of the above situation, there is an urgent need to provide a high-power battery pack balancing device based on relays and intelligent heat dissipation to overcome the shortcomings in current practical applications. Utility Model Content

[0009] The purpose of this invention is to provide a high-power battery pack balancing device based on relays and intelligent heat dissipation, which aims to solve the problems mentioned in the background art.

[0010] This utility model is implemented as follows: a high-power battery pack balancing device based on relays and intelligent heat dissipation, comprising:

[0011] The host computer and the discharge device used to discharge the battery cells with excessively high voltage;

[0012] A motherboard used for real-time monitoring of cell voltage, control of the discharge device, and data exchange with the host computer.

[0013] The discharge device includes a discharge resistor and a heat sink.

[0014] As a further embodiment of this utility model: the motherboard includes a power module, an MCU control unit, an AFE voltage acquisition unit, a communication module, a relay switch matrix, an LED display module, and a fan control module;

[0015] The power supply module is connected to the MCU control unit, AFE voltage acquisition unit, communication module, relay switch matrix, LED display module, and fan control module, respectively.

[0016] The AFE voltage acquisition unit is connected to the MCU control unit and is used to acquire the cell voltage and transmit the data to the MCU control unit;

[0017] The MCU control unit is connected to the relay switch matrix, LED display module, fan control module and communication module respectively, and is used to process voltage data and generate control commands;

[0018] The communication module is connected to the host computer to enable data interaction;

[0019] The relay switch matrix is ​​connected to the discharge device to control the on / off state of the discharge circuit of the discharge device.

[0020] As a further embodiment of this utility model: the power module adopts a hierarchical power architecture, integrating two DC-DC converters and one LDO regulator.

[0021] As a further embodiment of this invention: one DC-DC converter converts the input voltage to 24V; the other DC-DC converter generates 5V voltage;

[0022] The LDO regulator steps down the 5V voltage to 3.3V.

[0023] As a further aspect of this invention, the AFE voltage acquisition unit employs a dedicated battery management analog front-end chip.

[0024] As a further embodiment of this utility model: each relay in the relay switch matrix is ​​independently connected to the positive terminal of a single battery cell, and the relay switch matrix control circuit consists of relays and switching transistors, with the switching transistors connected in series in the relay power supply circuit.

[0025] As a further embodiment of this utility model: the circuit of the LED display module consists of multi-color LEDs and a switching transistor, with the switching transistor connected in series in the LED power supply circuit.

[0026] As a further embodiment of this utility model: the circuit of the fan control module consists of a relay and a switching transistor, with the switching transistor connected in series in the relay power supply circuit, and the relay connected in series in the positive terminal of the fan power supply.

[0027] As a further embodiment of this utility model, the communication module is equipped with both CAN and 485 communication modes.

[0028] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0029] 1. Significantly Improved Equalization Speed: While maintaining a relatively simple BMS circuit structure (compared to active equalization), this invention replaces the MOSFET switch in the traditional passive equalization scheme with a high-power relay. The relay can withstand a much larger current than the switching transistor, allowing for a larger equalization current (supporting approximately 3A of equalization current). This increases the discharge current from the milliamp level of traditional passive equalization to the several amp level, which is dozens of times higher than traditional passive equalization. This greatly improves the discharge speed and effectively solves the problem of the low discharge speed of traditional passive equalization schemes. It can quickly achieve cell voltage equalization and meet the equalization requirements in scenarios with large-capacity battery packs or severe inconsistencies in cell voltage.

[0030] 2. Highly Efficient and Flexible Heat Dissipation Solution: This utility model's discharge device innovatively employs a combined active and passive heat dissipation solution. Passive heat conduction is achieved through a heat sink, while an optional fan can be installed for active cooling as needed. This solution not only effectively solves the significant heat generation problem caused by high-current balancing but also provides the flexibility of on-demand cooling with the optional fan, adapting to different operating conditions. Compared to the single and inefficient external balancing circuitry of traditional passive balancing solutions, this solution offers higher heat dissipation efficiency, better ensuring thermal safety during the balancing process and improving system reliability.

[0031] 3. Reduced Cost and Complexity: Compared to existing BMS active balancing solutions, this invention eliminates complex power components (such as boost modules and energy storage modules), reducing the use of most power components and lowering the risk of component failure. It also simplifies the circuit structure, making circuit design simpler. The relay control logic and balancing algorithm are relatively simplified, eliminating the need for complex software development and verification processes, thus reducing development and maintenance costs. Furthermore, the low switching frequency of the relays in this invention virtually eliminates EMI problems, avoiding the need for additional filtering and shielding designs required in active balancing solutions due to EMI generated by high-frequency switching, saving development time and costs.

[0032] 4. Reduced Equipment Costs and Assembly Difficulty: Existing external equalization devices on the market are expensive and complex to assemble, significantly increasing costs when large-scale use is required. This utility model device has a simple structure, mainly composed of a main circuit board, a discharge device, and a host computer. The components are readily available and inexpensive, and the overall device is easy to assemble, greatly reducing equipment costs and assembly difficulty. Especially in large-scale equalization scenarios, it can significantly reduce the user's cost investment.

[0033] 5. Enhanced Operability and Interactivity: This utility model is equipped with a host computer monitoring system and LED status indicators, constructing an independent local-remote dual-channel monitoring solution. The host computer has functions such as real-time data monitoring, remote command sending, and data recording, realizing human-computer interaction and remote monitoring. Users can easily understand the system's working status and remotely control the system through the host computer. The LED status indicators can provide users with instantaneous and intuitive visual feedback on the system's working status without relying on the host computer. Even when network communication is interrupted or the host computer software malfunctions, users can still know the system status in a timely manner. The dual-channel collaborative operation greatly improves the operability and interactivity of the device, solving the problem of the lack of operability and interactivity in current equalization devices, and improving the reliability of the device system and the user experience. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a structural diagram of the present invention.

[0036] Figure 2 This is a block diagram of the main board in this utility model.

[0037] Figure 3 This is the circuit diagram of the power supply module in this utility model.

[0038] Figure 4 This is a circuit diagram of the relay switch matrix control circuit in this utility model.

[0039] Figure 5 This is the circuit diagram of the LED display module in this utility model.

[0040] Figure 6 This is the circuit diagram of the fan control module in this utility model.

[0041] Figure 7 This is the logic diagram for the equalization algorithm.

[0042] Figure 8 This is a control diagram of the relay switch matrix in this utility model.

[0043] In the attached diagram: 1-motherboard, 2-discharge device, 3-host computer. Detailed Implementation

[0044] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0045] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0047] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0048] Please see Figures 1-8 This utility model provides a high-power battery pack balancing device based on relays and intelligent heat dissipation. The device consists of three parts (the energy storage battery is the object of use): motherboard 1, discharge device 2, and host computer 3.

[0049] This device, centered on motherboard 1, uses an MCU to control high-power relays connecting battery cells and discharge resistors to rapidly dissipate energy from overvoltaged cells. It also features a high-efficiency cooling system and an interactive interface with a host computer (HPC) 3. The core of the solution utilizes a relay matrix to control a high-power resistor to discharge the target battery cell, supporting approximately 3A of balancing current and significantly improving balancing efficiency. Motherboard 1 monitors the battery cell voltage in real time via an AFE unit, with the MCU intelligently deciding on the start and stop of balancing. The discharge device 2 innovatively designs a composite cooling system—passively conducting heat through a heatsink combined with optional active cooling by a fan—ensuring thermal safety under high-power dissipation. Furthermore, the solution integrates remote interactive functionality with the host computer 3, enabling real-time data monitoring, manual command control, and flexible parameter configuration, achieving intelligent operation and management. Simultaneously, motherboard 1 is equipped with an LED display module, using LED color changes (green / yellow / red) to clearly distinguish various complex system states such as "standby," "balancing in progress," and "fault." This forms an independent local-remote dual-channel monitoring system with the host computer 3.

[0050] The motherboard 1 adopts a highly integrated design, combining power, control, data acquisition, communication, drive and LED indicator modules to form a safe, reliable and controllable battery balancing solution.

[0051] The main modules and functions of motherboard 1 are as follows:

[0052] like Figure 2 As shown, motherboard 1 includes a power module, an MCU control unit, an AFE voltage acquisition unit, a communication module, a relay switch matrix, an LED display module, and a fan control module.

[0053] The main function of the power module is to convert the total battery voltage or external power supply into stable low-voltage DC power.

[0054] like Figure 3 As shown, the power module in this solution adopts a hierarchical power architecture, integrating two DC-DC converters and one LDO regulator. One DC-DC converter converts the input voltage to 24V, dedicated to driving high-power loads such as external fans; the other DC-DC converter generates 5V to power peripheral components of the main board 1, such as relay coils and communication chips; to further improve power quality, the LDO steps down the 5V to a stable and clean 3.3V to power core precision components (such as AFE and MCU). This design balances efficiency and accuracy, ensuring the overall stability and reliability of the system.

[0055] For the voltage acquisition unit, this solution uses a mainstream dedicated battery management analog front-end (AFE). The AFE chip is directly powered by the battery pack and supports a wide operating voltage range (-0.3V to 85V). Its core function is to acquire the voltage of 13 series-connected battery cells in real time with high precision, with a typical measurement error of less than ±10mV. All acquired cell voltage data is uploaded to the MCU via a high-speed SPI communication interface for subsequent voltage state calculations and balancing decisions.

[0056] The MCU control module, as the core processing unit of the entire equalization device, is responsible for high-precision voltage data processing and intelligent equalization decision-making. Its workflow is as follows: The MCU receives real-time voltage data from each cell collected by the AFE (Automatic Factor Exchange). First, it calculates the average voltage of the battery pack and uses it as the benchmark for equalization. Then, the MCU compares the voltage of each individual cell with the average voltage. If a cell's voltage is higher than the benchmark and exceeds a preset threshold, a control command is generated to drive the corresponding relay to close, forming a discharge circuit between the cell and the parallel power resistor, achieving heat dissipation-based equalization. During the equalization process, the MCU continuously monitors voltage changes and dynamically updates the average voltage value. A closed-loop control strategy is adopted; when the difference between the target cell's voltage and the average voltage is detected to be lower than a set tolerance, the relay is automatically disconnected, and equalization stops to avoid over-discharge. Simultaneously, the MCU uploads all cell voltage data, equalization status, relay action records, and system operating parameters to the host computer in real-time via the communication module, providing users with visual monitoring and in-depth analysis capabilities, thereby achieving observable and controllable control of the entire battery system. This solution includes a multi-color LED status indicator directly driven by the MCU. This LED serves as a local redundant backup for remote monitoring by the host computer (HPC3). Even when network communication is interrupted or the HPC3 software malfunctions, it still ensures that users are aware of the system status, greatly enhancing system security and reliability.

[0057] Each relay in the relay switch matrix is ​​independently connected to the positive terminal of a single battery cell. Upon receiving a command from the MCU, the relay of the target battery cell closes, opening the path from the cell to the discharge resistor, thus achieving directional discharge of a single cell, i.e., each battery cell discharges independently.

[0058] Figure 4 This is a relay control circuit diagram, consisting of components such as a relay and a switching transistor. The switching transistor is connected in series in the relay power supply circuit. When the relay needs to operate, the MCU controls the switching transistor to close, the relay power supply is restored, and the relay is energized.

[0059] The LED display module is controlled by an MCU and displays different colors according to the equilibrium state. It provides users with instantaneous and intuitive visual feedback on the system's operating status without relying on a host computer. This solves the monitoring inconvenience that can arise from relying on a PC screen in complex industrial environments.

[0060] like Figure 5 As shown, the circuit consists of multi-color LEDs and switching transistors, with the switching transistors connected in series in the LED power supply circuit. When the MCU needs the LED status display to show a certain color, it controls the power supply path of that color LED to light it up.

[0061] The fan control module is controlled by the MCU. If the fan is needed, the host computer can send a command to close the relay connected to the fan power supply, so that the fan power supply is turned on and it starts to run.

[0062] like Figure 6 As shown, the circuit consists of components such as a relay and a switching transistor. The switching transistor is connected in series in the relay power supply circuit, and the relay is connected in series in the positive terminal of the fan power supply. To operate the fan, the MCU controls the switching transistor to close, which in turn closes the relay, providing power to the fan and causing it to run.

[0063] The communication module is equipped with both CAN and RS-485 communication modes for user convenience. The communication module transmits data to the host computer (3), enabling real-time monitoring, remote command processing, and data logging.

[0064] The discharge equalization logic is as follows:

[0065] like Figure 7 As shown, the MCU receives voltage information from the AFE acquisition unit and, based on the algorithm, identifies battery cells whose voltage exceeds a certain specification value relative to the average voltage. The MCU then sends a command to the relay drive circuit via its I / O port to open the relay corresponding to the battery cell's channel, directly connecting the cell to the discharge resistor and initiating equalization. During the equalization process, the voltage difference between the battery cell's voltage and the average voltage is continuously measured. When the voltage falls below the specification value, the relay corresponding to the channel is closed, and equalization stops.

[0066] The principle of relay switch matrix control is as follows:

[0067] like Figure 8 As shown, each relay is independently connected to the positive terminal (high-voltage side) and power resistor of a single battery cell. The MCU (low-voltage side) safely isolates and controls the on / off state of the high-voltage battery discharge circuit by controlling the relay coils (low-voltage control circuit). The relay matrix design allows the MCU to selectively connect any high-voltage cell that needs to be discharged to a shared discharge power resistor. When one or more cells need to be equalized, the MCU sends a signal to close the relay, and the cell begins individual discharge equalization; when discharge equalization is not needed, the MCU sends a signal to open the relay, stopping the discharge equalization.

[0068] The core innovation of this utility model lies in:

[0069] 1. Innovative load-bearing capacity: While maintaining a relatively simple circuit structure of the BMS (compared to active balancing), it achieves discharge balancing with a larger current and faster speed than traditional passive balancing.

[0070] 2. Cost Innovation: Significantly reduces the system cost of implementing active balancing (eliminating complex power components) while improving BMS reliability. Compared to common active balancing schemes, it avoids EMI problems caused by high-frequency switching, saving development time and costs. The relay control logic and balancing algorithm are relatively simplified.

[0071] 3. Innovative Thermal Management System: The active + passive composite cooling solution not only solves the huge heat generation problem caused by high current balancing, but also provides flexibility for on-demand cooling with the optional fan design, which can adapt to different operating conditions.

[0072] 4. Innovative Control Strategy: A host computer 3 monitoring system is configured to realize human-computer interaction and remote monitoring; by coordinating the control of the local LED status indicator and the remote host computer 3 monitoring interface through the MCU, an independent dual-channel monitoring scheme is constructed.

[0073] In addition, the definitions of terms used in this utility model are as follows:

[0074] 1. A BMS (Battery Management System) is an electronic system used to monitor the operating status of a battery pack (such as voltage, current, and temperature), manage battery balancing, protect the battery from overcharging and over-discharging, extend battery life, and improve battery safety. BMSs are widely used in electric vehicles, energy storage systems, portable electronic devices, and other fields.

[0075] 2. Passive balancing: A resistor and a switch (usually a MOSFET) are connected in parallel next to a cell with a high voltage. When an excessively high voltage cell is detected, its corresponding switch is turned on. A portion of the current from this high-voltage cell flows through the resistor, and the electrical energy is converted into heat and dissipated. Discharge continues until its voltage approaches the average value of the other cells.

[0076] 3. Active balancing: Transferring excess energy from high-voltage cells to low-voltage cells (or sometimes to the entire battery pack). For example, using a DC-DC converter to boost / buck the energy from high-voltage cells and then charge low-voltage cells or the entire battery pack.

[0077] 4. MCU: Microcontroller Unit. MCU is an abbreviation for Microcontroller Unit. It is responsible for information processing, complex calculations, intelligent decision-making, system control, and communication. It is the intelligent core of the BMS, realizing state estimation, management strategies, and advanced functions.

[0078] 5. AFE: Analog Front End. AFE is an abbreviation for Analog Front End. It specializes in acquiring key analog signals (voltage, temperature) of the battery with high precision, high speed, and high safety, and is responsible for the lowest-level fast hardware protection.

[0079] 6. Relay: The core actuator that enables precise, safe, and reliable switching of the discharge path of a high-voltage single battery. It utilizes electromagnetic principles to allow the MCU to control the switching of a high-voltage, high-current circuit with a weak, low-voltage signal.

[0080] 7. Power resistor: A resistor used to consume a large amount of electrical energy (usually ≥1 watt) and convert it into heat.

[0081] 8. Heatsink: An aluminum alloy component that quickly and efficiently removes heat generated by the resistor through metal and fins. A layer of thermal grease is applied between the power resistor and the heatsink to fill the tiny gaps and ensure that heat can be transferred to the heatsink without hindrance.

[0082] 8. Host Computer 3: This is a software program that runs on a computer (or industrial control computer) and connects to the hardware motherboard via cables (such as USB, CAN, or Ethernet) to enable human-computer interaction.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

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