Heat dissipation method of battery management system, battery management system and energy storage system

Abstract

The application provides a battery management system heat dissipation method, a battery management system and an energy storage system, and relates to the technical field of energy storage. The method comprises the following steps: acquiring voltages of a plurality of battery cells; determining a target battery cell, a target equalization resistor and a target heat dissipation area based on the voltages of the plurality of battery cells, the target battery cell being a battery cell that needs to be discharged for equalization, the target equalization resistor being an equalization resistor corresponding to the target battery cell, and the target heat dissipation area being a heat dissipation area in which the target equalization resistor is located; turning on a target equalization switch device, the target equalization switch device being an equalization switch device corresponding to the target equalization resistor; acquiring a temperature of the target heat dissipation area; and adjusting a duty cycle of a control signal of the target equalization switch device and / or a rotating speed of a heat dissipation fan corresponding to the target heat dissipation area based on the temperature of the target heat dissipation area. The method provided by the application is helpful to improve the heat dissipation efficiency of the equalization resistor.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a heat dissipation method for a battery management system, a battery management system, and an energy storage system. Background Technology

[0002] In a battery management system (BMS), to ensure voltage consistency among multiple battery cells, a balancing circuit is typically used to control cell voltage balance. Currently, the most widely used balancing method is passive balancing, which involves discharging the cells through balancing resistors to lower the voltage of the higher-voltage cells, thereby achieving voltage consistency.

[0003] In related technologies, equalizing resistors are soldered onto circuit boards. The heat dissipation efficiency of equalizing resistors is poor, which leads to excessively high temperatures, affecting component reliability and voltage sampling accuracy. Prolonged high temperatures may also cause damage to the circuit board or other safety hazards. Summary of the Invention

[0004] This application provides a heat dissipation method for a battery management system, a battery management system, and an energy storage system, which helps to improve the heat dissipation efficiency of the balancing resistor.

[0005] This application provides a heat dissipation method for a battery management system, including: Obtain the voltage of multiple battery cells; The target cell, target equalization resistor, and target heat dissipation area are determined based on the voltage of multiple cells. The target cell is the cell that needs to be discharged and equalized, the target equalization resistor is the equalization resistor corresponding to the target cell, and the target heat dissipation area is the heat dissipation area where the target equalization resistor is located. Turn on the target equalization switch device, which is the equalization switch device corresponding to the target equalization resistor; Obtain the temperature of the target heat dissipation area; The duty cycle of the control signal for the target equalization switching device and / or the speed of the cooling fan corresponding to the target heat dissipation area are adjusted based on the temperature of the target heat dissipation area.

[0006] In one possible implementation, the duty cycle of the control signal of the target equalization switching device is negatively correlated with the temperature of the target heat dissipation area, while the speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the temperature of the target heat dissipation area.

[0007] In one possible implementation, adjusting the duty cycle of the control signal for the target equalization switching device and / or the rotational speed of the cooling fan corresponding to the target heat dissipation area based on the temperature of the target heat dissipation area includes: When the temperature of the target heat dissipation area is less than the first threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the first duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the first speed. When the temperature of the target heat dissipation area is greater than or equal to the first threshold and less than the second threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the second duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the second speed. When the temperature of the target heat dissipation area is greater than or equal to the second threshold and less than the third threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the third duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the third speed. When the temperature of the target heat dissipation area is greater than or equal to the third threshold and less than the fourth threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the fourth duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the fourth speed. When the temperature of the target heat dissipation area is greater than or equal to the fourth threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the fifth duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the fifth speed. Among them, the first duty cycle > the second duty cycle > the third duty cycle > the fourth duty cycle > the fifth duty cycle; the first speed < the second speed < the third speed < the fourth speed < the fifth speed.

[0008] In one possible implementation, the first duty cycle is 100% and the first rotational speed is 0. The method also includes: When the temperature of the target heat dissipation area is greater than or equal to the first threshold and less than the second threshold for the first time, the speed of the cooling fan corresponding to the target heat dissipation area is first adjusted to the second speed, and after a first preset time delay, the duty cycle of the control signal of the target equalization switch device is adjusted to the second duty cycle; or the duty cycle of the control signal of the target equalization switch device is first adjusted to the second duty cycle, and after a second preset time delay, the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the second speed.

[0009] One possible implementation of the method also includes: When multiple target equalization resistors are operating simultaneously, and the average or highest temperature of the target heat dissipation area where these resistors are located exceeds the fifth threshold, Determine the lowest cell voltage among multiple target cells corresponding to multiple target equalization resistors; Based on the absolute value of the difference between the voltage of multiple target cells and the voltage of the lowest target cell among the multiple target cells, sort them from low to high, and turn off the target equalization switch device corresponding to at least one target cell with the highest sorting.

[0010] One possible implementation of the method also includes: When the average or highest temperature of the target heat dissipation area where multiple target equalization resistors are located drops to the sixth threshold, the target equalization switching devices that have been turned off are turned on in sequence according to the absolute value of the difference between the voltage of multiple target cells and the lowest cell voltage among the multiple target cells, from low to high.

[0011] In one possible implementation, the speed of the cooling fan corresponding to the target heat dissipation area is also positively correlated with the balancing current, which is the current flowing through the target balancing resistor.

[0012] One possible implementation of the method also includes: Determine the target minimum cell voltage, which is the lowest cell voltage among multiple cells; Calculate the voltage difference between the target cell voltage and the target lowest cell voltage; Adjust the speed of the cooling fan corresponding to the target heat dissipation area based on the voltage difference.

[0013] In one possible implementation, the speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the voltage difference.

[0014] This application also provides a battery management system, including: Circuit board; The circuit board is equipped with multiple equalizing resistors and multiple equalizing switches. The equalizing resistors are used to equalize the voltage of the corresponding battery cells. The multiple equalizing resistors are connected to multiple equalizing switches, and the multiple equalizing switches are used to control the conduction or disconnection of the corresponding connected equalizing resistors. The circuit board is divided into multiple heat dissipation areas. Each heat dissipation area is equipped with a temperature detection device and at least one equalizing resistor. The temperature detection device is used to detect the temperature of the heat dissipation area. Each heat dissipation area is equipped with a corresponding heat dissipation structure, which includes a cooling fan.

[0015] In one possible implementation, when a single equalizing resistor is provided in the heat dissipation area, the temperature detection device is set within a preset distance range of the equalizing resistor; When multiple equalizing resistors are provided in the heat dissipation area, the temperature detection device is placed in the middle of the multiple equalizing resistors.

[0016] In one possible implementation, the system also includes: The housing and circuit board are mounted inside the housing via a fixed bracket.

[0017] This application also provides an energy storage system, including: a plurality of battery cells and a battery management system as shown in the above embodiments.

[0018] The beneficial effects of this application are as follows: This application provides a heat dissipation method for a battery management system, a battery management system, and an energy storage system. Multiple balancing resistors and multiple balancing switches are arranged on the circuit board of the battery management system, which is divided into multiple heat dissipation areas. Each heat dissipation area is equipped with a temperature detection device and at least one balancing resistor. Each heat dissipation area has a corresponding heat dissipation structure, including a cooling fan. When the battery cell needs to be balanced during discharge, the corresponding balancing switch is activated, thereby turning on the corresponding balancing resistor. The temperature of the heat dissipation area where the balancing resistor is located is detected in real time. Based on the temperature of the heat dissipation area, the duty cycle of the control signal of the balancing switch and / or the speed of the corresponding cooling fan are adjusted to quickly dissipate the heat generated by the balancing circuit, improving the heat dissipation efficiency of the balancing resistor and thus improving the safety and reliability of the balancing circuit. Furthermore, by coordinating the adjustment of the duty cycle of the control signal of the balancing switch and the speed of the cooling fan, a dynamic balance between heat and electricity can be achieved when the temperature is abnormal, maximizing balancing efficiency while ensuring safety, and improving the safety, reliability, and balancing performance of the battery management system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a battery management system provided in an embodiment of this application; Figure 2 A schematic diagram of the heat dissipation structure provided in the embodiments of this application; Figure 3 This is a schematic diagram of another battery management system provided in an embodiment of this application; Figure 4 This is a schematic flowchart of a heat dissipation method for a battery management system provided in an embodiment of this application. Detailed Implementation

[0020] In this embodiment of the application, unless otherwise stated, the character " / " indicates that the preceding and following objects are in an OR relationship. For example, A / B can represent A or B. "AND / OR" describes the relationship between the associated objects, indicating that three relationships can exist. For example, A AND / OR B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0021] It should be noted that the terms "first" and "second" used in the embodiments of this application are used only for distinguishing descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated, nor should they be construed as indicating or implying order.

[0022] In the embodiments of this application, "at least one" means one or more, and "more than one" means two or more. Furthermore, "at least one of the following" or similar expressions refer to any combination of these items, which may include any combination of a single item or a plurality of items. For example, at least one of A, B, or C can represent: A, B, C, A and B, A and C, B and C, or A, B, and C. Each of A, B, and C can be an element itself or a set containing one or more elements.

[0023] In this application, terms such as "exemplary," "in some embodiments," and "in another embodiment" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0024] In the embodiments of this application, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction, their meanings are consistent. Similarly, in the embodiments of this application, "communication" and "transmission" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction, their meanings are consistent. For example, transmission can include sending and / or receiving, and can be a noun or a verb.

[0025] In the embodiments of this application, the term "equal to" can be used in conjunction with "greater than" to apply to technical solutions employing the condition of "greater than", and can also be used in conjunction with "less than" to apply to technical solutions employing the condition of "less than". It should be noted that when "equal to" is used with "greater than", it cannot be used with "less than"; and when "equal to" is used with "less than", it cannot be used with "greater than".

[0026] In related technologies, the equalizing resistor is soldered onto the circuit board and relies solely on the natural heat dissipation of the equalizing resistor. The heat dissipation efficiency is poor, which can easily lead to the equalizing resistor temperature being too high, affecting the reliability of the component. When the heat is conducted to the battery management system chip, it affects the voltage sampling accuracy. Prolonged high temperature may also cause damage to the circuit board or other safety hazards.

[0027] Based on the above problems, this application proposes a battery management system, such as... Figure 1 As shown, Figure 1This is a schematic diagram of a battery management system provided in an embodiment of this application. The battery management system includes: a circuit board 1, on which multiple equalizing resistors 10 and multiple equalizing switches 11 are provided. The multiple equalizing resistors 10 are connected to the multiple equalizing switches 11, and the multiple equalizing switches 11 are used to control the conduction or disconnection of the correspondingly connected equalizing resistors 10, thereby realizing the equal discharge of the battery cells. Each equalizing resistor 10 is connected to a corresponding battery cell 2 for equalizing the voltage of the corresponding battery cell. The circuit board 1 is divided into multiple heat dissipation areas, and each heat dissipation area is provided with a temperature detection device 12 and at least one equalizing resistor 10. The temperature detection device 12 is used to detect the temperature of the heat dissipation area.

[0028] by Figure 1 Taking the battery management system shown as an example, circuit board 1 is divided into two heat dissipation areas (a1 and a2), each including two equalizing resistors 10 and a temperature detection device 12. Each heat dissipation area is equipped with a corresponding heat dissipation structure ( Figure 1 (Not shown in the image), the heat dissipation structure includes a cooling fan. The cooling fan can blow directly onto the balancing resistors, using forced convection to remove heat. It is understood that this application does not limit the number of balancing resistors 10 included in each heat dissipation area; the number of balancing resistors 10 can also be 1, 2, 3, etc.

[0029] Optionally, the battery management system also includes a battery management chip 13, which may be an analog front end (AFE) chip used to collect cell voltage and temperature and perform battery balancing.

[0030] The equalization switching device in this application is implemented using a MOSFET. The equalization switching device can be a discrete MOSFET, that is, an independent power MOSFET is used as the equalization switching device, or it can be an integrated MOSFET, that is, the equalization switching device is integrated inside the battery management chip 13.

[0031] It should be noted that the Battery Management System (BMS) adopts a three-tiered architecture to achieve comprehensive and efficient management of the battery system. This architecture divides the management system into three levels, from bottom to top: Level 1 Battery Pack (PACK) Management (Level 1 BMS), Level 2 Battery Cluster Management (Level 2 BMS), and Level 3 Battery Stack Management (Level 3 BMS). The Level 1 BMS, as the bottom-level execution unit, directly monitors each cell within a single battery pack, responsible for real-time data collection such as cell voltage and temperature. The Level 2 BMS, as the intermediate control unit, manages a battery cluster composed of multiple battery packs connected in parallel. The Level 3 BMS, as the highest-level system controller, is responsible for monitoring the entire battery stack. The balancing function is specifically executed by the Level 1 BMS; therefore, the battery management system referred to in this embodiment is the Level 1 BMS.

[0032] In some embodiments, Figure 2 This is a schematic diagram of the heat dissipation structure provided in the embodiments of this application. Each heat dissipation area is covered with a layer of... Figure 2 The heat dissipation structure shown includes a cooling fan 141, a heat-conducting unit 142, and a heat dissipation unit 143. The cooling fan 141 is located on the side of the heat dissipation unit 143. The heat from the equalizing resistor 10 is conducted to the heat dissipation unit 143 through the heat-conducting unit 142, and then the cooling fan 141 cools the heat dissipation unit 143. This method is suitable for situations where the resistor layout is compact and cannot be directly exposed to airflow, and it can evenly distribute hot spots and improve heat dissipation efficiency.

[0033] Optionally, the heat-conducting unit 142 can be a heat-conducting copper sheet, a heat-conducting aluminum sheet, or a heat-conducting pad. One end of the heat-conducting unit 142 is attached to the equalizing resistor 10, and the other end is connected to the heat dissipation unit 143, so that the heat generated by the equalizing resistor 10 can be conducted to the heat dissipation unit 143 through the heat-conducting unit 142.

[0034] Optionally, the heat dissipation unit 143 is a metal heat sink.

[0035] In some embodiments, when a single equalizing resistor is provided in the heat dissipation area, the temperature detection device is located within a preset distance range of the equalizing resistor; when multiple equalizing resistors are provided in the heat dissipation area, the temperature detection device is located in the middle of the multiple equalizing resistors.

[0036] Specifically, when a single equalizing resistor is provided in the heat dissipation area, the temperature detection device is set within a preset distance range of the equalizing resistor, for example, it can be set near the equalizing resistor, so that the temperature detection device forms thermal coupling with the equalizing resistor through the heat conduction unit, and can detect the temperature change of the heat dissipation area where the equalizing resistor is located in real time.

[0037] When multiple equalizing resistors are installed within the heat dissipation area, the temperature detection device is positioned between these equalizing resistors. (Continue to refer to...) Figure 1 , Figure 1 Each heat dissipation area includes two equalizing resistors 10, and the temperature detection device 12 is positioned between the two equalizing resistors 10, making the temperature detection device 12 measurement faster and more accurate.

[0038] It should be noted that, in this embodiment, the term "middle" should be interpreted broadly, referring to either the precise geometric center of a region or the region within a certain range around that center.

[0039] Optionally, the temperature detection device can be a negative temperature coefficient (NTC) thermistor or other temperature sensor.

[0040] In some embodiments, the battery management system further includes a housing, in which the circuit board is mounted via a mounting bracket. Figure 3 This is a schematic diagram of another battery management system provided in an embodiment of this application, as shown below. Figure 3 As shown, the battery management system also includes a housing 4. The circuit board 1 is installed inside the housing 4 by a fixing bracket 3. The housing 4 covers the circuit board 1 and the heat dissipation structure to prevent external objects from accidentally contacting the internal components and to avoid mechanical collision damage.

[0041] Optionally, the housing 4 is a non-sealed structure. Ventilation holes can be opened in the housing 4 to allow air to enter and exit freely. Together with the cooling fan, a convection channel is formed to dissipate the heat generated by the equalizing resistor, MOSFET and other heat-generating components to the external environment in a timely manner, and to avoid heat accumulation.

[0042] This application also proposes an energy storage system, including: multiple battery cells and a battery management system as shown in the above embodiments. The multiple battery cells are connected in series and / or in parallel for storing and releasing electrical energy; the battery management system is electrically connected to the multiple battery cells for monitoring the voltage and temperature of the multiple battery cells and performing equalization control.

[0043] In this application, multiple balancing resistors and multiple balancing switches are arranged on the circuit board of the battery management system, and the circuit board is divided into multiple heat dissipation areas. Each heat dissipation area is equipped with a temperature detection device and at least one balancing resistor, and each heat dissipation area is equipped with a corresponding heat dissipation structure, including a cooling fan. The heat dissipation structure enables the heat generated by the balancing circuit to be quickly dissipated, improving the heat dissipation efficiency of the balancing resistors, thereby improving the safety and reliability of the balancing circuit. Furthermore, the use of zoned heat dissipation and temperature monitoring forms thermal protection for the battery balancing circuit, enhancing the stability and protection capability of the battery management system.

[0044] Furthermore, embodiments of this application also propose a heat dissipation method for a battery management system. Figure 4 A flowchart illustrating the heat dissipation method of the battery management system provided in this application embodiment specifically includes the following steps: Step S41: Obtain the voltage of multiple battery cells.

[0045] Specifically, the voltage of multiple battery cells is collected through a battery management chip.

[0046] Step S42: Determine the target cell, target equalization resistor, and target heat dissipation area based on the voltage of multiple cells.

[0047] Among them, the target cell is the cell that needs to be discharged and balanced, the target balancing resistor is the balancing resistor corresponding to the target cell, and the target heat dissipation area is the heat dissipation area where the target balancing resistor is located.

[0048] In some embodiments, the target cell can be determined by the voltage difference method to identify the cell that needs to be discharged and balanced.

[0049] Specifically, after obtaining the voltages of multiple battery cells, the lowest cell voltage is determined. The voltage difference between each individual cell's voltage and the lowest cell voltage is then calculated. Each voltage difference is compared to a preset discharge equalization threshold (e.g., 20mV, which can be set according to cell characteristics and application scenarios). If the voltage difference for a particular cell is greater than the preset discharge equalization threshold, that cell is identified as the target cell and discharge equalization is required. When the voltage difference for that cell is less than the preset equalization shutdown threshold, discharge equalization for that cell is stopped.

[0050] In other embodiments, the target cell can also be determined by the State of Charge (SOC) difference. The SOC of each cell is estimated by the open-circuit voltage method or the current integration method, and equalization is initiated when the difference between the SOC of a single cell and the target value (such as the minimum SOC of a single cell) exceeds a threshold.

[0051] Step S43: Turn on the target equalization switch device.

[0052] The target equalization switch device is the equalization switch device corresponding to the target equalization resistor. After determining the target cell and the target equalization resistor, the target cell is equalized by turning on the target equalization switch device corresponding to the target equalization resistor.

[0053] Step S44: Obtain the temperature of the target heat dissipation area.

[0054] Specifically, the temperature of the target heat dissipation area is detected by a temperature detection device (such as an NTC thermistor) within the target heat dissipation area. The temperature detection device is placed near the target balancing resistor to detect the temperature of the heat dissipation area where the target balancing resistor is located. This temperature can effectively reflect the heating trend and heat dissipation requirements of the target balancing resistor.

[0055] Step S45: Adjust the duty cycle of the control signal of the target equalization switching device and / or the speed of the cooling fan corresponding to the target heat dissipation area based on the temperature of the target heat dissipation area.

[0056] In this application, the equalizing switch device controls the ratio of its on-time to off-time (i.e., duty cycle) using a pulse width modulation (PWM) signal. Increasing the duty cycle means that the equalizing switch device has a higher proportion of on-time, the energy path is on for a longer period, and the target cell releases more energy per unit time. Correspondingly, the equalizing resistor has a longer on-time, resulting in more energy consumption per unit time. Conversely, decreasing the duty cycle means that the equalizing switch device has a lower proportion of on-time, the energy path is on for a shorter period, the target cell releases less energy per unit time, and the equalizing resistor has a shorter on-time, resulting in less energy consumption per unit time.

[0057] By monitoring the temperature of the target heat dissipation area, the heating trend and heat dissipation requirements of the target equalization resistor can be sensed in real time. Based on this temperature, the duty cycle of the control signal of the target equalization switching device can be adjusted, or the speed of the cooling fan corresponding to the target heat dissipation area can be adjusted, or the duty cycle of the control signal of the target equalization switching device and the speed of the cooling fan corresponding to the target heat dissipation area can be adjusted. When the temperature is abnormal, dynamic balance between heat and electricity can be achieved, maximizing equalization efficiency while ensuring safety, and improving the safety, reliability and equalization performance of the battery management system.

[0058] In some embodiments, the duty cycle of the control signal of the target equalization switching device is negatively correlated with the temperature of the target heat dissipation area, and the speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the temperature of the target heat dissipation area.

[0059] When the temperature rises, the cooling fan accelerates, enhancing the heat dissipation capacity of the heat dissipation structure and reducing the duty cycle of the control signal of the equalization switch, thus reducing the heat generated by the equalization resistor. Conversely, when the temperature decreases, the cooling fan decelerates, reducing energy consumption and increasing the duty cycle of the control signal of the equalization switch, thereby improving equalization efficiency. This indicates that the duty cycle of the control signal of the target equalization switch is negatively correlated with the temperature of the target heat dissipation area, while the speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the temperature of the target heat dissipation area.

[0060] Optionally, when the temperature rises, the duty cycle of the control signal of the equalization switching device is reduced while the cooling fan is accelerated, so that the heat generated by the equalization current and the heat dissipation capacity are dynamically matched, avoiding stopping the equalization when the temperature exceeds the limit. This not only enhances active heat dissipation but also reduces passive heat generation, improves the heat dissipation efficiency of the equalization resistor, and realizes the linkage regulation of heat and electricity, maximizing the equalization efficiency while ensuring safety.

[0061] In some embodiments, the rotational speed of the cooling fan corresponding to the target heat dissipation area is also positively correlated with the balancing current, which is the current flowing through the target balancing resistor.

[0062] The heat generation power of passive balancing is related to the balancing current and the balancing resistance, and the balancing current also affects the heat generation. When the current flowing through the target balancing resistor increases, the heat generation increases, requiring an increase in the cooling fan speed to accelerate heat dissipation; conversely, when the current flowing through the target balancing resistor decreases, the heat generation decreases, requiring a decrease in the cooling fan speed to reduce power consumption. This indicates a positive correlation between the cooling fan speed corresponding to the target heat dissipation area and the balancing current.

[0063] In some embodiments, adjusting the duty cycle of the control signal of the target equalization switching device and / or the speed of the cooling fan corresponding to the target heat dissipation area based on the temperature of the target heat dissipation area includes: When the temperature of the target heat dissipation area is less than the first threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the first duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the first speed. When the temperature of the target heat dissipation area is greater than or equal to the first threshold and less than the second threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the second duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the second speed. When the temperature of the target heat dissipation area is greater than or equal to the second threshold and less than the third threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the third duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the third speed. When the temperature of the target heat dissipation area is greater than or equal to the third threshold and less than the fourth threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the fourth duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the fourth speed. When the temperature of the target heat dissipation area is greater than or equal to the fourth threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the fifth duty cycle, and / or the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the fifth speed. Among them, the first duty cycle > the second duty cycle > the third duty cycle > the fourth duty cycle > the fifth duty cycle; the first speed < the second speed < the third speed < the fourth speed < the fifth speed.

[0064] Optionally, the first threshold is 45°C, the second threshold is 55°C, the third threshold is 70°C, and the fourth threshold is 85°C. The first duty cycle is 100% (i.e., equalization fully on), the second duty cycle is 80%, the third duty cycle is 50%, the fourth duty cycle is 20%, and the fifth duty cycle is 0% (i.e., equalization stopped). The first fan speed is 0 (i.e., fan off), the second fan speed is 30% of full speed, the second fan speed is 50% of full speed, the second fan speed is 80% of full speed, and the second fan speed is 100% of full speed (i.e., fan fully on). In this embodiment, full speed refers to the rated maximum speed of the fan. It is understood that the settings of the temperature threshold, duty cycle threshold, and fan speed threshold can be calibrated and optimized according to the actual application scenario (such as the number of battery cells, the magnitude of the equalization current, the area of ​​the heat sink, the ambient temperature, etc.), and this application does not limit them.

[0065] In this application, when the temperature rises, the speed of the cooling fan corresponding to the target heat dissipation area can be increased and / or the duty cycle of the control signal of the target equalization switching device can be decreased to improve the heat dissipation efficiency of the target equalization resistor. Furthermore, this application employs multi-level threshold control of temperature, fan speed, and PWM duty cycle to achieve graded thermal protection for the target equalization resistor. The heat dissipation intensity is dynamically adjusted according to the actual heat generation level, further improving the heat dissipation efficiency of the target equalization resistor and avoiding frequent fan start-stop or long-term full-speed operation, thus reducing system power consumption.

[0066] Optionally, the fan speed and the duty cycle of the control signal can be adjusted simultaneously in each temperature range to achieve coordinated regulation of heat and electricity.

[0067] For example, when the temperature of the target heat dissipation area is less than 45°C, the cooling fan is turned off (i.e., the fan speed is 0), the target equalization switching device is continuously turned on with the maximum duty cycle (100%), and the equalization circuit runs at full speed; When the temperature of the target heat dissipation area is greater than or equal to 45°C and less than 55°C, the cooling fan runs at 30% of its full speed (i.e., the fan speed is 30% of the rated maximum speed), and the duty cycle of the control signal of the target equalization switch device is adjusted to 80% to slightly reduce the equalization heat generation. When the temperature of the target heat dissipation area is greater than or equal to 55°C and less than 70°C, the cooling fan runs at 50% of its full speed (i.e., the fan speed is 50% of the rated maximum speed), and the duty cycle of the control signal of the target equalization switch device is adjusted to 50%, which moderately reduces the equalization heat generation while enhancing heat dissipation. When the temperature of the target heat dissipation area is greater than or equal to 70°C and less than 85°C, the cooling fan runs at 80% of its full speed (i.e., the fan speed is 80% of the rated maximum speed), and the duty cycle of the control signal of the target equalization switch device is adjusted to 20%, which greatly reduces the equalization heat generation and enhances heat dissipation. When the temperature of the target heat dissipation area is greater than or equal to 85°C, the cooling fan runs at its highest speed (i.e., 100% full speed), the duty cycle of the control signal of the target equalization switch device drops to zero, that is, equalization stops and enters thermal protection state. After the temperature drops to a safe range (such as less than 70°C or less than 55°C), equalization is restored step by step according to the above stages.

[0068] This application achieves maximum continuity of the equalization function by coordinating the duty cycle of the control signal of the equalization switching device with the fan speed, while ensuring safety. This avoids the "one-size-fits-all" approach of shutting down at high temperatures, which leads to a significant decrease in equalization efficiency in related technologies.

[0069] In some embodiments, the first duty cycle is 100% and the first rotational speed is 0. The heat dissipation method of the battery management system provided in this application embodiment further includes: When the temperature of the target heat dissipation area is greater than or equal to the first threshold and less than the second threshold for the first time, the speed of the cooling fan corresponding to the target heat dissipation area is first adjusted to the second speed, and after a first preset time delay, the duty cycle of the control signal of the target equalization switch device is adjusted to the second duty cycle; or the duty cycle of the control signal of the target equalization switch device is first adjusted to the second duty cycle, and after a second preset time delay, the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the second speed.

[0070] For example, when the temperature of the target heat dissipation area first exceeds or equals 45°C but is less than 55°C, the corresponding cooling fan for the target heat dissipation area is activated, that is, the fan speed is adjusted from 0 to 30% of full speed. Activating the fan first forces convection cooling, which can quickly suppress the temperature rise. After extending the first preset time to allow the fan to reach a stable operating state, the target equalization switch is then switched from continuous conduction mode to intermittent mode, that is, the duty cycle of the control signal of the target equalization switch is adjusted from 100% to 80%. This avoids reducing the conduction time of the equalization resistor before the fan has fully taken effect, which could lead to insufficient equalization.

[0071] Alternatively, when the temperature of the target heat dissipation area first exceeds 45°C but is less than 55°C, first adjust the operating mode of the equalization switch to intermittent mode. That is, adjust the duty cycle of the control signal of the target equalization switch from 100% to 80%. This can immediately reduce the heat generation power and suppress the temperature rise at the source. After extending the second preset time, start the cooling fan corresponding to the target heat dissipation area, that is, adjust the fan speed from 0 to 30% of full speed. Extending the second preset time is to observe the actual effect of the intermittent mode. If the temperature is stable or slowly decreasing, there is no need to start the fan, saving energy. If the temperature continues to rise, then start the fan to supplement heat dissipation, avoiding frequent fan start-stop and reducing power consumption.

[0072] Optionally, the first preset duration is 5 to 10 seconds, and the second preset duration is 15 to 30 seconds.

[0073] In some embodiments, the heat dissipation method of the battery management system provided in this application further includes: When multiple target equalization resistors are operating simultaneously, and the average or highest temperature of the target heat dissipation area where these resistors are located exceeds the fifth threshold, Determine the lowest cell voltage among multiple target cells corresponding to multiple target equalization resistors; Based on the absolute value of the difference between the voltage of multiple target cells and the voltage of the lowest target cell among the multiple target cells, sort them from low to high, and turn off the target equalization switch device corresponding to at least one target cell with the highest sorting.

[0074] When multiple equalizing resistors are turned on at the same time, as the temperature rises, in order to prioritize maintaining the equalization of the cells with higher voltage, the equalizing resistors corresponding to the cells with lower voltage are turned off first. This reduces heat generation and allows the high-voltage cells to continue discharging and equalizing, which is beneficial to the voltage consistency of the battery pack.

[0075] For example, when five equalizing resistors (R1, R2, R3, R4, and R5) are working simultaneously, and the average temperature of the heat dissipation area where the five equalizing resistors are located is greater than the fifth threshold (e.g., 75°C), the lowest cell voltage among the five cells (C1, C2, C3, C4, and C5) corresponding to the five equalizing resistors is determined. Then, the absolute value of the difference between the voltage of each of the five cells and the lowest cell voltage is calculated. After sorting them from low to high, the resulting order is C2, C3, C5, C1, and C4. The equalizing switch device corresponding to at least one cell in the order that is ranked first is turned off. For example, the equalizing switch devices corresponding to cells C2 and C3 are turned off, while the equalizing switch devices corresponding to cells C5, C1, and C4 are kept working.

[0076] In other embodiments, the target cells can be sorted from highest to lowest based on the absolute value of the difference between their voltages and the lowest voltage among the target cells, and the target equalization switch corresponding to at least one target cell in the lower order of the sorting can be turned off. For example, if the target cells are sorted from highest to lowest as C4, C1, C5, C3, and C2, the equalization switches corresponding to cells C2 and C3 can be turned off, while the equalization switches corresponding to cells C5, C1, and C4 can remain operational.

[0077] In some embodiments, the heat dissipation method of the battery management system provided in this application further includes: When the average or highest temperature of the target heat dissipation area where multiple target equalization resistors are located drops to the sixth threshold, the target equalization switching devices that have been turned off are turned on in sequence according to the absolute value of the difference between the voltage of multiple target cells and the lowest cell voltage among the multiple target cells, from low to high.

[0078] In this embodiment, when the average temperature of the target heat dissipation area where multiple target equalization resistors are located drops to the sixth threshold (e.g., 60°C), the target equalization switching devices that were turned off at the end of the sequence are turned on in sequence to gradually restore the equalization operation of the battery cells until the equalization is fully restored, thereby achieving both thermal protection and improving equalization efficiency.

[0079] For example, when the average temperature of the heat dissipation area where the five equalizing resistors are located exceeds the fifth threshold (e.g., 75°C), the equalizing switches corresponding to cells C2 and C3 are turned off, while cells C5, C1, and C4 remain operational. When the average temperature of the heat dissipation area where the five equalizing resistors are located decreases to the sixth threshold (e.g., 60°C), the equalizing switches corresponding to cells C2 and C3 are turned on sequentially, with the later-ordered equalizing switches being turned on first. That is, the equalizing switch corresponding to cell C3 is turned on first, followed by the equalizing switch corresponding to cell C2, prioritizing the restoration of equalization operation for cells with higher voltages.

[0080] In other embodiments, the target equalization switches that were previously off can be turned on sequentially according to the absolute value of the difference between the voltage of the multiple target cells and the voltage of the lowest target cell among the multiple target cells, from high to low. For example, if the cells are ordered from high to low as C4, C1, C5, C3, and C2, the equalization switches corresponding to cells C2 and C3 can be turned on sequentially, with the earlier equalization switches turned on first, that is, the equalization switch corresponding to cell C3 is turned on first, and then the equalization switch corresponding to cell C2 is turned on.

[0081] In some embodiments, the heat dissipation method of the battery management system provided in this application further includes: Determine the target minimum cell voltage, which is the lowest cell voltage among multiple cells; Calculate the voltage difference between the target cell voltage and the target lowest cell voltage; Adjust the speed of the cooling fan corresponding to the target heat dissipation area based on the voltage difference.

[0082] In this embodiment, after obtaining the voltages of multiple cells, the lowest cell voltage among the multiple cells is determined, i.e., the target lowest cell voltage is determined. Then, the voltage difference between the cell that needs to be discharged and balanced (i.e. the target cell) and the target lowest cell voltage is calculated. Adjusting the fan speed by the voltage difference helps to improve the heat dissipation efficiency of the balancing resistor.

[0083] In some embodiments, the rotational speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the voltage difference.

[0084] Specifically, the greater the voltage difference between the target cell and the lowest voltage among multiple cells, the more severe the imbalance, and the greater the heat dissipation of the balancing resistor corresponding to the target cell. Therefore, by setting the cooling fan speed to be positively correlated with the voltage difference—the greater the voltage difference, the higher the fan speed; the smaller the voltage difference, the lower the fan speed—on-demand cooling is achieved. This provides sufficient cooling to prevent overheating of the balancing resistor under strong balancing conditions, and reduces the fan speed to decrease energy consumption under weak or no balancing conditions, thereby improving the reliability of the battery management system.

[0085] In summary, this application sets multiple balancing resistors and multiple balancing switching devices on the circuit board of the battery management system, and divides the circuit board into multiple heat dissipation areas. Each heat dissipation area is equipped with a temperature detection device and at least one balancing resistor, and each heat dissipation area has a corresponding heat dissipation structure, including a cooling fan. When the battery cell needs to be discharged and balanced, the corresponding balancing switching device is activated, thereby conducting the corresponding balancing resistor, and the temperature of the heat dissipation area where the balancing resistor is located is detected in real time. The duty cycle of the control signal of the balancing switching device and / or the speed of the cooling fan corresponding to the heat dissipation area are adjusted according to the temperature of the heat dissipation area, so that the heat generated by the balancing circuit can be quickly dissipated, improving the heat dissipation efficiency of the balancing resistor, thereby improving the safety and reliability of the balancing circuit. Furthermore, through dual-variable collaborative control with a negative correlation between duty cycle and temperature and a positive correlation between fan speed and temperature, a dynamic balance between heat and electricity is achieved when the temperature is abnormal, maximizing balancing efficiency while ensuring safety, and improving the safety, reliability, and balancing performance of the battery management system.

[0086] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A heat dissipation method for a battery management system, characterized in that, The method includes: Obtain the voltage of multiple battery cells; The target cell, target equalization resistor, and target heat dissipation area are determined based on the voltage of the multiple cells. The target cell is the cell that needs to be discharged and equalized. The target equalization resistor is the equalization resistor corresponding to the target cell. The target heat dissipation area is the heat dissipation area where the target equalization resistor is located. Turn on the target equalization switch device, wherein the target equalization switch device is the equalization switch device corresponding to the target equalization resistor; Obtain the temperature of the target heat dissipation area; The duty cycle of the control signal of the target equalization switch device and the speed of the cooling fan corresponding to the target heat dissipation area are adjusted based on the temperature of the target heat dissipation area. When multiple target equalization resistors are operating simultaneously, and the average or highest temperature of the target heat dissipation area where the multiple target equalization resistors are located is greater than the fifth threshold, Determine the lowest cell voltage among the multiple target cells corresponding to the multiple target equalization resistors; Based on the absolute value of the difference between the voltage of the plurality of target cells and the voltage of the lowest target cell among the plurality of target cells, they are sorted from low to high, and the target equalization switch device corresponding to at least one target cell ranked first is turned off.

2. The heat dissipation method for the battery management system according to claim 1, characterized in that, The duty cycle of the control signal of the target equalization switch device is negatively correlated with the temperature of the target heat dissipation area, and the speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the temperature of the target heat dissipation area.

3. The heat dissipation method for the battery management system according to claim 1, characterized in that, The step of adjusting the duty cycle of the control signal for the target equalization switching device and the rotational speed of the cooling fan corresponding to the target heat dissipation area based on the temperature of the target heat dissipation area includes: When the temperature of the target heat dissipation area is less than the first threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the first duty cycle, and the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the first speed. When the temperature of the target heat dissipation area is greater than or equal to the first threshold and less than the second threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the second duty cycle, and the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the second speed. When the temperature of the target heat dissipation area is greater than or equal to the second threshold and less than the third threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the third duty cycle, and the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the third speed. When the temperature of the target heat dissipation area is greater than or equal to the third threshold and less than the fourth threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the fourth duty cycle, and the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the fourth speed. When the temperature of the target heat dissipation area is greater than or equal to the fourth threshold, the duty cycle of the control signal of the target equalization switch device is adjusted to the fifth duty cycle, and the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the fifth speed. Among them, the first duty cycle > the second duty cycle > the third duty cycle > the fourth duty cycle > the fifth duty cycle; the first speed < the second speed < the third speed < the fourth speed < the fifth speed.

4. The heat dissipation method for the battery management system according to claim 3, characterized in that, The first duty cycle is 100%, the first rotational speed is 0, and the method further includes: When the temperature of the target heat dissipation area is greater than or equal to the first threshold and less than the second threshold for the first time, the speed of the cooling fan corresponding to the target heat dissipation area is first adjusted to the second speed, and after a first preset time delay, the duty cycle of the control signal of the target equalization switch device is adjusted to the second duty cycle; or the duty cycle of the control signal of the target equalization switch device is first adjusted to the second duty cycle, and after a second preset time delay, the speed of the cooling fan corresponding to the target heat dissipation area is adjusted to the second speed.

5. The heat dissipation method for the battery management system according to claim 1, characterized in that, The method further includes: When the average or highest temperature of the target heat dissipation area where the multiple target equalization resistors are located decreases to the sixth threshold, the target equalization switching devices that have been turned off are turned on in sequence according to the absolute value of the difference between the voltage of the multiple target cells and the lowest cell voltage among the multiple target cells, from low to high.

6. The heat dissipation method for the battery management system according to claim 2, characterized in that, The rotational speed of the cooling fan corresponding to the target heat dissipation area is also positively correlated with the balancing current, which is the current flowing through the target balancing resistor.

7. The heat dissipation method for the battery management system according to claim 1, characterized in that, The method further includes: Determine the target minimum cell voltage, wherein the target minimum cell voltage is the lowest cell voltage among the plurality of cells; Calculate the voltage difference between the voltage of the target cell and the voltage of the target lowest cell; Adjust the speed of the cooling fan corresponding to the target heat dissipation area based on the voltage difference.

8. The heat dissipation method of the battery management system according to claim 7, characterized in that, The rotational speed of the cooling fan corresponding to the target heat dissipation area is positively correlated with the voltage difference.

9. A battery management system, characterized in that, A heat dissipation method for performing a battery management system as described in any one of claims 1-8, the system comprising: Circuit board; The circuit board is provided with multiple equalizing resistors and multiple equalizing switches. The equalizing resistors are used to equalize the voltage of the corresponding battery cells. The multiple equalizing resistors are connected to the multiple equalizing switches. The multiple equalizing switches are used to control the conduction or disconnection of the corresponding connected equalizing resistors. The circuit board is divided into multiple heat dissipation areas. Each heat dissipation area is equipped with a temperature detection device and at least one equalizing resistor. The temperature detection device is used to detect the temperature of the heat dissipation area. Each heat dissipation area is equipped with a corresponding heat dissipation structure, which includes a cooling fan.

10. The battery management system according to claim 9, characterized in that, When a single equalizing resistor is provided in the heat dissipation area, the temperature detection device is set within a preset distance range of the equalizing resistor; When multiple equalizing resistors are provided in the heat dissipation area, the temperature detection device is located in the middle of the multiple equalizing resistors.

11. The battery management system according to claim 9, characterized in that, The system also includes: The circuit board is mounted inside the housing via a mounting bracket.

12. An energy storage system, characterized in that, include: Multiple battery cells and a battery management system as described in any one of claims 9-11.

Images