Thermal management method of energy storage equipment, energy storage equipment and storage medium

Abstract

According to the thermal management method of the energy storage equipment, the energy storage equipment comprises a plurality of battery modules, and each battery module comprises a fan and a plurality of battery cells; the plurality of temperature sensors comprise a first temperature sensor and a second temperature sensor; the heat exchanger comprises a first fan, a heat exchange unit and a second fan, and the heat exchanger is used for conducting heat exchange on fluid in the energy storage equipment and fluid outside the energy storage equipment; the method comprises the following steps: in response to triggering of a cooling starting condition, controlling a first fan, a second fan and a fan of a battery module to operate, and controlling a first air volume to be approximately the same as the total air volume of the fan; the cooling starting condition comprises that the highest temperature of the battery cell is greater than or equal to a first temperature threshold and the first temperature difference value is greater than or equal to a first temperature difference threshold; the first temperature difference value is defined as the difference value between the highest temperature of the battery cell and the environment temperature; the first air volume is defined as the air volume generated by operation of the first fan, and the total fan air volume is defined as the sum of all air volumes generated by operation of the fan.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to thermal management methods for energy storage devices, energy storage devices, and storage media. Background Technology

[0002] During the charging and discharging process, the battery cells of energy storage devices generate a large amount of heat, causing the battery cell temperature to rise. Excessive battery cell temperature will reduce the battery cell's lifespan and may even cause fire or explosion. Therefore, it is necessary to dissipate heat from the battery cells of energy storage devices to reduce their temperature. Summary of the Invention

[0003] This application provides a thermal management method for energy storage devices, energy storage devices, and storage media, with the aim of managing the heat dissipation of energy storage devices.

[0004] In a first aspect, a thermal management method for an energy storage device is provided. The thermal management method is applied to the energy storage device, which includes: multiple battery modules, each battery module including a fan and multiple battery cells; multiple temperature sensors, including a first temperature sensor and a second temperature sensor, the first temperature sensor being used to monitor the temperature of the battery cells, and the second temperature sensor being used to monitor the ambient temperature outside the energy storage device; and a heat exchanger, including a first fan, a heat exchange unit, and a second fan, the heat exchanger being used to exchange heat between fluid inside the energy storage device and fluid outside the energy storage device. The method includes: in response to a cooling activation condition being triggered, controlling the operation of the first fan, the second fan, and the main fan, and controlling a first airflow to be approximately the same as the total airflow of the fans; wherein the cooling activation condition includes: the highest temperature of the battery cells being greater than or equal to a first temperature threshold, and a first temperature difference value being greater than or equal to the first temperature difference threshold; the first temperature difference value being defined as the difference between the highest temperature of the battery cells and the ambient temperature; the first airflow being defined as the airflow generated by the operation of the first fan; and the total airflow of the fans being defined as the sum of all airflow generated by the operation of the fans.

[0005] In this technical solution, the highest temperature of the battery cell is greater than or equal to a first temperature threshold, and the difference between the highest temperature of the battery cell and the ambient temperature outside the energy storage device is greater than a first temperature difference threshold, indicating that the battery cell temperature is high and requires cooling. The large temperature difference between the inside and outside of the energy storage device meets the cooling activation conditions. Controlling the operation of the first fan, second fan, and general fan in the heat exchanger helps accelerate heat dissipation in the energy storage device, reduces the internal battery cell temperature, and extends the battery cell's lifespan. The airflow generated by the first fan is approximately the same as the total airflow generated by the general fan, preventing hot air from the rear of the battery module from flowing back to the front of the battery module or causing redundant airflow from the first fan, which would reduce heat dissipation efficiency.

[0006] In conjunction with the first aspect, in one possible implementation, the aforementioned ambient temperatures are located in different temperature ranges, and the aforementioned first temperature thresholds are different.

[0007] Different ambient temperatures correspond to different cell temperature thresholds, preventing the energy storage device from failing to achieve its cooling effect when the temperature difference between the inside and outside of the device is unsuitable.

[0008] In conjunction with the first aspect, in one possible implementation, the temperature range includes a first temperature range, a second temperature range, and a third temperature range, wherein the temperature of the first temperature range is higher than the temperature of the second temperature range, and the temperature of the second temperature range is higher than the temperature of the third temperature range; the first temperature threshold includes: a first value corresponding to the first temperature range, a second value corresponding to the second temperature range, and a third value corresponding to the third temperature range; wherein the first value is greater than the second value, and the third value is greater than the second value.

[0009] In conjunction with the first aspect, in one possible implementation, it further includes: responding to the ambient temperature being in different temperature ranges, controlling a first duty cycle to be at least partially positively correlated with the temperature range; wherein, the period of the electrical signal controlling the first fan when the cooling start condition is triggered is defined as a first period, the duration of controlling the operation of the first fan in the first period is defined as a first duration, and the first duty cycle is defined as the ratio of the first duration to the first period.

[0010] The duty cycle of the internal fan is at least partially positively correlated with the ambient temperature range. When the ambient temperature is not high, the heat dissipation conditions are better. Controlling the internal fan to operate at a lower speed can achieve better heat dissipation and help reduce energy consumption.

[0011] In conjunction with the first aspect, in one possible implementation, it further includes: in response to the aforementioned cooling activation condition being triggered, controlling a first duty cycle to be positively correlated with the highest temperature of the battery cell; wherein, the period of the electrical signal controlling the first fan when the aforementioned cooling activation condition is triggered is defined as a first period, the duration of controlling the operation of the first fan in the first period is defined as a first duration, and the first duty cycle is defined as the ratio of the first duration to the first period.

[0012] The duty cycle of the internal fan is positively correlated with the highest temperature of the battery cell, which helps to quickly reduce the temperature of the battery cell and achieve rapid heat dissipation.

[0013] In conjunction with the first aspect, one possible implementation further includes: determining the first temperature threshold corresponding to the current temperature range according to a preset time interval.

[0014] Temperature thresholds are determined according to preset time intervals to avoid rapid changes in adjustment strategies and prevent frequent adjustments to the speed of fans and / or blowers.

[0015] In conjunction with the first aspect, one possible implementation also includes: controlling the first air volume and the second air volume to be approximately the same; wherein the second air volume is defined as the air volume generated by the operation of the second fan.

[0016] Controlling the airflow generated by the internal and external fans to be roughly the same helps to balance the air in the heat exchange unit and reduce the noise generated by the fans.

[0017] In conjunction with the first aspect, in one possible implementation, it further includes: in response to the temperature equalization activation condition being triggered, controlling the operation of the first fan and the fan, and controlling the first air volume to be approximately the same as the total air volume of the fan; wherein the temperature equalization activation condition includes: a second temperature difference value greater than or equal to a second temperature difference threshold; the second temperature difference value is defined as the difference between the highest temperature of the battery cell and the lowest temperature of the battery cell.

[0018] If the difference between the highest and lowest temperatures of a battery cell exceeds the second temperature difference threshold, it indicates a significant temperature difference between the cells, meeting the conditions for temperature equalization activation. Controlling the operation of the first fan and the main fan helps accelerate the fluid thermal circulation within the energy storage device, balances the cell temperatures between battery modules, reduces the temperature difference between battery modules, and promotes consistent charging and discharging of the battery modules. Ensuring the airflow generated by the first fan is approximately the same as the total airflow generated by the main fan prevents hot air from flowing back from the rear of the battery module to the front or causing redundant airflow from the first fan, which would reduce heat dissipation efficiency.

[0019] In conjunction with the first aspect, one possible implementation further includes: controlling the second duty cycle to be positively correlated with the second temperature difference value; wherein, the period of the electrical signal controlling the first fan when the above-mentioned temperature equalization opening condition is triggered is defined as the second period, the duration of controlling the operation of the first fan in the second period is defined as the second duration, and the second duty cycle is defined as the ratio of the second duration to the second period.

[0020] The duty cycle of the internal fan is positively correlated with the temperature difference, which helps to quickly reduce the temperature difference between the cells, thereby shortening the working time of the internal fan and the main fan, and reducing the energy consumption of the energy storage device.

[0021] In conjunction with the first aspect, in one possible implementation, it further includes: in response to both the cooling start condition and the temperature equalization start condition being triggered, controlling the first air volume to the maximum value that satisfies both the cooling start condition and the temperature equalization start condition; and / or in response to the cooling start condition not being triggered and the temperature equalization start condition being triggered, controlling or maintaining the second fan off.

[0022] When both cooling and temperature equalization activation conditions are triggered, controlling the airflow of the internal fan to the maximum value required to meet these conditions helps with rapid heat dissipation and / or temperature equalization, reducing the operating time of the internal fan and other fans. When the cooling activation condition is not triggered but the temperature equalization activation condition is triggered, controlling or keeping the second fan off helps save energy.

[0023] In conjunction with the first aspect, one possible implementation further includes: controlling a third duty cycle that is positively correlated with the temperature of the battery module; wherein, the period of the electrical signal controlling the fan when the temperature equalization activation condition is triggered is defined as the third period, the duration of controlling the fan to operate in the third period is defined as the third duration, and the third duty cycle is defined as the ratio of the third duration to the third period; the temperature of the battery module is defined as: i) the highest temperature of the battery cell in the battery module, or ii) the average temperature of the battery cell in the battery cell module.

[0024] The fan's duty cycle is positively correlated with the battery module's temperature, which helps to quickly reduce the temperature difference between battery modules, thereby shortening the fan's operating time.

[0025] In conjunction with the first aspect, in one possible implementation, controlling the third duty cycle to be positively correlated with the temperature of the battery module includes: controlling the third duty cycle to increase in response to the temperature of the first battery module being higher than the average temperature of the battery modules; and controlling the third duty cycle to decrease in response to the temperature of the second battery module being lower than the average temperature of the battery modules; wherein the average temperature of the battery modules is defined as the average temperature of all battery modules.

[0026] When the battery module temperature is higher than its average temperature, the fan duty cycle is increased, and the fan speed is increased to accelerate heat dissipation from the hot battery module. When the battery module temperature is lower than its average temperature, the fan duty cycle is decreased to maintain a constant total airflow.

[0027] In conjunction with the first aspect, in one possible implementation, the control of the third duty cycle being positively correlated with the temperature of the battery module further includes: in response to the fact that the highest temperature of the battery cell and the lowest temperature of the battery cell belong to the same battery module in the energy storage device, controlling the third duty cycle to remain unchanged.

[0028] In conjunction with the first aspect, in one possible implementation, the heat exchanger further includes a heater, and the method further includes: in response to the heating start-up condition being triggered, controlling the operation of the first fan, the fan, and the heater, controlling or maintaining the second fan off, and controlling the first air volume to be approximately the same as the total air volume of the fan; wherein the heating start-up condition includes: the minimum temperature of the battery cell is less than a second temperature threshold.

[0029] If the lowest temperature of the battery cell is less than the second temperature threshold, it means that the temperature of the battery cell is low and needs to be heated. Once the heating start-up conditions are met, the operation of the heater, internal fan and fan in the heat exchanger will be controlled, which will help the energy storage device to heat up quickly.

[0030] In conjunction with the first aspect, one possible implementation further includes: controlling the fourth duty cycle to be negatively correlated with the lowest temperature of the aforementioned battery cell; wherein, the period of the electrical signal controlling the aforementioned first fan when the heating start condition is triggered is defined as the fourth period, the duration of controlling the operation of the aforementioned first fan in the aforementioned fourth period is defined as the fourth duration, and the aforementioned fourth duty cycle is defined as the ratio of the aforementioned fourth duration to the aforementioned fourth period.

[0031] The duty cycle of the internal fan is negatively correlated with the lowest temperature of the battery cell, which helps to quickly increase the temperature of the battery module.

[0032] In conjunction with the first aspect, in one possible implementation, it further includes: in response to both the heating start condition and the temperature equalization start condition being triggered, controlling the first air volume to the maximum value that satisfies both the heating start condition and the temperature equalization start condition; wherein the temperature equalization start condition includes: a second temperature difference value greater than or equal to a second temperature difference threshold; the second temperature difference value is defined as the difference between the highest temperature of the battery cell and the lowest temperature of the battery cell.

[0033] When both heating and temperature equalization conditions are triggered, controlling the airflow of the internal fan to the maximum value that satisfies both conditions helps to quickly raise the temperature and shorten the operating time of the fan and ventilator.

[0034] In conjunction with the first aspect, in one possible implementation, it further includes: controlling the first fan, the second fan, and the ventilator to shut down in response to both the cooling shutdown condition and the temperature equalization shutdown condition being triggered, or in response to both the temperature equalization shutdown condition and the heating shutdown condition being triggered; wherein the cooling shutdown condition includes: i) the highest temperature of the battery cell is less than a third temperature threshold, and the third temperature threshold is less than the first temperature threshold, or ii) the first temperature difference value is less than a third temperature difference threshold, and the third temperature difference threshold is less than the first temperature difference threshold; the temperature equalization shutdown condition includes: the second temperature difference value is less than a fourth temperature difference threshold, and the fourth temperature difference threshold is less than the second temperature difference threshold; the heating shutdown condition includes: the lowest temperature of the battery cell is greater than a fourth temperature threshold, and the fourth temperature threshold is greater than the second temperature threshold.

[0035] When both shutdown conditions are triggered, controlling the fan and blower to shut down helps reduce the energy consumption of the energy storage device. When the highest temperature of the battery cell is less than a third temperature threshold smaller than the first temperature threshold, or when the first temperature difference is less than a third temperature difference threshold smaller than the first temperature difference threshold, the cooling shutdown condition is triggered. When the difference between the highest temperature and the lowest temperature of the battery cell is less than a fourth temperature difference threshold smaller than the second temperature difference threshold, the temperature equalization shutdown condition is triggered. When the lowest temperature of the battery cell is greater than a fourth temperature threshold larger than the second temperature threshold, the heating shutdown condition is triggered to avoid frequent start-stop of the fan and blower.

[0036] Secondly, another thermal management method for an energy storage device is provided. This method is applied to an energy storage device, which includes: multiple battery modules, each battery module including a fan and multiple battery cells; multiple temperature sensors, including a first temperature sensor and a second temperature sensor, the first temperature sensor monitoring the temperature of the battery cells and the second temperature sensor monitoring the ambient temperature outside the energy storage device; and a heat exchanger, including a first fan, a heat exchange unit, and a second fan, the heat exchanger enabling heat exchange between fluids inside and outside the energy storage device. The method includes: in response to a temperature equalization activation condition being triggered, controlling the operation of the first fan and the battery cells, and controlling the first airflow to be approximately the same as the total airflow of the fans; wherein the temperature equalization activation condition includes: a second temperature difference value greater than or equal to a second temperature difference threshold; the second temperature difference value defined as the difference between the highest temperature and the lowest temperature of the battery cells; the first airflow defined as the airflow generated by the operation of the first fan; and the total airflow of the fans defined as the sum of all airflow generated by the operation of the fans.

[0037] In this technical solution, the difference between the highest and lowest temperatures of the battery cells exceeds the second temperature difference threshold, indicating a significant temperature difference between the cells. This meets the conditions for temperature equalization activation. Controlling the operation of the first fan and the main fan helps accelerate the fluid thermal circulation within the energy storage device, balances the cell temperatures between battery modules, reduces the temperature difference between battery modules, and promotes consistent charging and discharging of the battery modules. Controlling the airflow generated by the first fan to be approximately the same as the total airflow generated by the main fan prevents hot air from flowing back from the rear of the battery module to the front of the battery module or causing redundancy in the airflow of the first fan, which would reduce heat dissipation efficiency.

[0038] In conjunction with the second aspect, one possible implementation also includes: controlling or maintaining the shutdown of the aforementioned second fan.

[0039] When the temperature equalization activation condition is triggered, controlling or keeping the second fan off is beneficial for saving energy consumption of the energy storage equipment.

[0040] Thirdly, an energy storage device is provided, comprising: multiple battery modules, each battery module including a fan and multiple battery cells; multiple temperature sensors, including a first temperature sensor and a second temperature sensor, the first temperature sensor being used to monitor the temperature of the battery cells, and the second temperature sensor being used to monitor the ambient temperature outside the energy storage device; a heat exchanger, including a first fan, a heat exchange unit, and a second fan, the heat exchanger being used to exchange heat between fluid inside the energy storage device and fluid outside the energy storage device; wherein the energy storage device is used to perform the thermal management method of the energy storage device described in the first aspect or the second aspect.

[0041] Fourthly, a computer-readable storage medium is provided, which stores a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the thermal management method of the energy storage device described in the first aspect or the second aspect. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the appearance of the energy storage device provided in the embodiments of this application;

[0043] Figure 2 and Figure 3 This is a cross-sectional schematic diagram of the energy storage device provided in the embodiments of this application;

[0044] Figure 4 This is a schematic diagram of a module for an energy storage device provided in an embodiment of this application;

[0045] Figure 5 A schematic flowchart illustrating a thermal management method for some energy storage devices provided in the embodiments of this application;

[0046] Figure 6A schematic flowchart illustrating the thermal management methods for some other energy storage devices provided in the embodiments of this application;

[0047] Figure 7 A schematic flowchart illustrating a thermal management method for some energy storage devices provided in the embodiments of this application;

[0048] Figure 8 This is a schematic diagram of the structure of an energy storage device provided in an embodiment of this application. Detailed Implementation

[0049] In the embodiments of this application, terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or order. For example, "first application" and "second application" are used to distinguish different applications, not to describe a specific order of applications. Features specified as "first" or "second" may explicitly or implicitly include one or more of those features.

[0050] The technical solution of this application is applicable to energy storage devices, such as residential energy storage devices, commercial and industrial energy storage devices, and UPS (Uninterruptible Power Supply). This application proposes three control strategies: heat dissipation control strategy, temperature equalization control strategy, and heating control strategy, which facilitate thermal management of energy storage devices under different operating conditions.

[0051] For ease of understanding, the energy storage device of this application will be introduced first. Please refer to... Figures 1-4 .

[0052] like Figures 1-4 As shown, the energy storage device 10 includes multiple battery modules 11 stacked along the height of the energy storage device 10. Each battery module 11 includes a fan 111 and multiple battery cells 112. In some embodiments, the number of fans 111 in each battery module 11 is one or more. It is understood that the number of battery modules 11 or the number of battery cells in each battery module 11 is defined by product requirements, and the electrical connection method of the battery cells in the battery module 12 includes series, parallel, or mixed connection (including series and parallel). In some embodiments, the battery cells are lithium-ion cells, nickel-metal hydride cells, nickel-cadmium cells, perovskite cells, lead-acid cells, or solid-state cells, etc.

[0053] like Figures 1-4 As shown, the energy storage device 10 includes a heat exchanger 12, which is used to exchange heat between the fluid inside the energy storage device 10 and the fluid outside the energy storage device 10. The energy storage device 10 uses the heat exchanger 12 to transfer the heat inside the energy storage device 10 to the external environment, thereby reducing the temperature inside the energy storage device 10 and cooling the battery module 11.

[0054] The heat exchanger 12 includes a first fan 121, a heat exchange unit 122, and a second fan 123. The fluid inside the energy storage device exchanges heat with the fluid outside the energy storage device through the heat exchange unit 122, thereby transferring the heat generated by the battery module 11 from inside the energy storage device 10 to the external environment. In the following text, the first fan 121 is also referred to as the internal fan, and the second fan 123 is also referred to as the external fan.

[0055] like Figure 2 As shown, the heat exchanger 12 includes an air inlet tu1 and a return air inlet tu2. A first fan 121 drives the fluid flow inside the energy storage device 10, causing the fluid to circulate within the device. When the first fan 121 operates, it drives the fluid flow inside the energy storage device 10. After heat exchange in the heat exchange unit 122, the fluid is blown out from the air inlet tu1. The fluid then flows through the air duct and fan 111 to the battery module 11, where it exchanges heat with the module, dissipating heat and lowering its temperature. After passing through the battery module 11, the fluid enters the heat exchange unit 12 through the return air inlet tu2 to exchange heat with external fluid. It can be understood that the first fan 121 is an internal circulation fan, the air inlet tu1 is an internal circulation air outlet, and the return air inlet tu2 is an internal circulation return air inlet.

[0056] like Figure 2 As shown, the heat exchanger 12 includes an air inlet tu3 and an air outlet tu4. A second fan 123 drives external fluid from the energy storage device 10 into the heat exchanger 12. When the second fan 123 operates, it drives external fluid from the air inlet tu3 into the heat exchange unit 122, where it exchanges heat with the fluid inside the energy storage device 10 before flowing out from the air outlet tu4, thus carrying away heat from inside the energy storage device 10. It is understood that the second fan 123 is an external circulation fan, the air inlet tu3 is the external circulation air inlet, and the air outlet tu4 is the external circulation air outlet.

[0057] In some embodiments, the heat exchanger 12 further includes a heater 124 disposed inside the energy storage device 10 for heating the battery cells. In some specific designs, the heater 124 is a PTC heater.

[0058] In some embodiments, the energy storage device 10 includes a plurality of temperature sensors 13, which include a first temperature sensor 131 and a second temperature sensor 132. The first temperature sensor 131 is used to monitor the cell temperature, and the second temperature sensor 132 is used to monitor the ambient temperature outside the energy storage device 10. It is understood that there are multiple first temperature sensors 131 and one or more second temperature sensors 132.

[0059] The heat dissipation control strategy, temperature equalization control strategy, and heating control strategy of this application are implemented in energy storage devices. The heat dissipation control strategy, temperature equalization control strategy, and heating control strategy of this application are described in detail below.

[0060] I. Heat dissipation control strategy

[0061] See Figure 5 , Figure 5 This is a flowchart illustrating a thermal management method for some energy storage devices provided in the embodiments of this application. For a description of the energy storage devices, please refer to the foregoing. Figures 1-4 The relevant description. For example... Figure 5 As shown, the method includes the following steps:

[0062] S201, in response to the cooling start condition being triggered, controls the operation of the first fan, the second fan, and the fan of the energy storage device, and controls the first air volume to be approximately the same as the total air volume of the fan.

[0063] In some embodiments, the cooling activation condition is set as follows: the highest temperature of the battery cell is greater than or equal to a first temperature threshold, and a first temperature difference value is greater than or equal to a first temperature difference threshold. The first temperature difference value is the difference between the highest temperature of the battery cell and the ambient temperature outside the energy storage device.

[0064] The highest temperature of a battery cell refers to the maximum value among all the temperatures monitored by the first temperature sensors in the energy storage device. Taking an energy storage device comprising 12 battery modules, each battery module including 24 battery cells and 12 first temperature sensors, with the 12 first temperature sensors distributed at different locations within the battery modules as an example, by acquiring data or electrical signals transmitted from the first temperature sensors, 12*12 = 144 cell temperatures can be calculated. These 144 cell temperatures form the first cell temperature set Tc = {Tc1, Tc2, Tc3, ..., Tc...} 144 The highest temperature of the battery cell is the maximum value in the first set of battery cell temperatures, that is, the maximum temperature of the battery cell is max{Tc1, Tc2, Tc3, ..., Tc 144}

[0065] The highest temperature of the battery cell is expressed as Tc. max Tc max =max{Tc1, Tc2, Tc3,…,Tc N}, where N represents the number of first temperature sensors in the energy storage device.

[0066] The first temperature difference is denoted as ΔT1, where ΔT1 = Tc. max-Te, where Te represents the ambient temperature outside the energy storage device. The ambient temperature outside the energy storage device is calculated by acquiring data or electrical signals transmitted from the second temperature sensor. When there are multiple second temperature sensors, data or electrical signals transmitted from multiple second temperature sensors are acquired, multiple temperature values ​​are calculated, and then a characteristic value is calculated from these multiple temperature values ​​to obtain the ambient temperature outside the energy storage device. For example, the average of multiple temperature values ​​can be used as the ambient temperature outside the energy storage device.

[0067] The first air volume is defined as the air volume generated when the first fan is running, and is denoted as Iav. The total fan air volume is defined as the sum of the air volumes generated by all fans during operation, and is denoted as Fat. Fav i Let M represent the air volume generated by the i-th fan, and M represent the number of fans in operation.

[0068] In some embodiments, the first air volume is approximately the same as the total fan air volume, including the following two cases: (1) the first air volume is the same as the total fan air volume, i.e., Iav = Fat; (2) the ratio of the first air volume to the total fan air volume is within a first ratio range. For example, the first ratio range is [95%, 105%], i.e., 95% ≤ Iav / Fat ≤ 105%.

[0069] The first fan and the fan operate after receiving a control signal, which has a duty cycle. By controlling the duty cycle of the first fan and the fan, the first air volume and the fan's air volume are obtained. In order to make the first fan and the total air volume of the fans approximately the same, the air volume of the first fan and the fan are first tested to determine the air volume generated by the first fan and the fan at different duty cycles. Based on the air volume generated by the first fan and the fan at different duty cycles, the duty cycle of the first fan and the duty cycle of each fan that satisfy the condition that the first air volume and the total air volume of the fans are approximately the same are determined (hereinafter referred to as the first fan duty cycle and the duty cycle of each fan that satisfy the first condition, i.e., the first condition indicates that the first air volume and the total air volume of the fans are approximately the same). The first fan duty cycle and the duty cycle of each fan that satisfy the first condition are stored in the energy storage device. In some embodiments, the fan and the first blower have different specifications, and their respective exhaust volumes are different under the same duty cycle control. Therefore, the duty cycle for controlling the operation of the first blower that satisfies the first condition is different from the duty cycle for controlling the operation of the fan that satisfies the first condition.

[0070] In some embodiments, there are multiple sets of duty cycles for the first fan and each fan that satisfy the first condition, to adapt to the duty cycle requirements of the energy storage device under different operating conditions. When the cooling activation condition is triggered or satisfied, the energy storage device selects an appropriate heat dissipation control strategy and drives the first fan and each fan to operate, ensuring that the first airflow is approximately the same as the total airflow of the fans. As a specific example, there are multiple sets of duty cycles for the first fan and each fan that satisfy the first condition. Each set includes one first fan duty cycle and M fan duty cycles, where M represents the number of fans. It is understood that the M fan duty cycles may be the same or different, and the fan duty cycles may differ from the first fan duty cycle.

[0071] Duty cycle refers to the proportion of time a control signal (the electrical signal controlling a fan or blower) keeps a device in an on / off state within a given period. Specifically, duty cycle is defined as the ratio of the duration of a pulse-width modulation (PWM) signal being high to the total duration of the PWM signal's cycle. Duty cycle is usually expressed as a percentage. Assuming one cycle is denoted as T, and the high-level time within one cycle is denoted as t, then the duty cycle is denoted as D, where D = (t / T) * 100%. For example, if a PWM signal has a period of 10 milliseconds and the high-level time within one cycle is 5 milliseconds, the duty cycle D = (5 / 10) * 100% = 50%.

[0072] The first temperature threshold and the first temperature difference threshold are thresholds used to determine whether the cooling activation conditions are met. For example, the first temperature difference threshold is set to 5°C. This application does not impose specific limitations on the first temperature difference threshold.

[0073] During the specific control interaction process, the processor in the energy storage device (the processor that issues control commands, such as the processor in the battery management system, or a processor independent of the battery management system) acquires data from the second temperature sensor to determine the ambient temperature outside the energy storage device, acquires data from the first temperature sensor to determine the highest temperature of the battery cell, and calculates the difference between the highest temperature of the battery cell and the ambient temperature outside the energy storage device as the first temperature difference value; it then determines whether the first temperature difference value is greater than or equal to the first temperature difference threshold, and whether the highest temperature of the battery cell is greater than or equal to the first temperature threshold, to determine whether the cooling start condition is met. If both of the above conditions are met, it indicates that the cooling start condition is met, and the processor sends start commands to the first fan, the second fan, and the fans of each battery module to control the operation of the first fan, the second fan, and the fans of the energy storage device, and outputs corresponding PWM signals to the first fan and each fan according to the appropriate heat dissipation control strategy and the duty cycle of the first fan and each fan that meets the first condition, so as to control the first airflow to be approximately the same as the total airflow of the fans.

[0074] In some embodiments, the ambient temperature is divided into multiple temperature ranges, and different temperature ranges correspond to different first temperature thresholds. That is, when the ambient temperature is in different temperature ranges, the first temperature threshold is different. In this way, by reasonably setting the cell temperature threshold, heat dissipation is avoided from being activated when the temperature difference between the inside and outside of the energy storage device is unsuitable, thus preventing the heat dissipation effect from being achieved.

[0075] In one specific embodiment, the multiple temperature ranges include a first temperature range, a second temperature range, and a third temperature range. The temperature of the first temperature range is higher than the temperature of the second temperature range, and the temperature of the second temperature range is higher than the temperature of the third temperature range. The first temperature threshold includes a first value corresponding to the first temperature range, a second value corresponding to the second temperature range, and a third value corresponding to the third temperature range. The first value is greater than the second value, and the third value is greater than the second value.

[0076] The first temperature range represents the temperature range when the ambient temperature is high, understood as the high-temperature range; the second temperature range represents the temperature range when the ambient temperature is moderate, understood as the medium-temperature range; and the third temperature range represents the temperature range when the ambient temperature is low, understood as the low-temperature range. In the high-temperature range, due to the high ambient temperature, initiating heat dissipation when the cell temperature is low will not achieve the desired cooling effect; instead, it will increase the energy consumption of the energy storage device. Therefore, the first temperature threshold for triggering heat dissipation is set to a first value, which is greater than the second value, raising the temperature threshold for triggering heat dissipation control to ensure that the heat dissipation control truly plays a role in cooling the cell. In the low-temperature range, due to the low ambient temperature and good external heat dissipation conditions, it is necessary to maintain the cell temperature. If the third value is set to be less than the second value, the cell temperature may drop significantly, resulting in a low-temperature cell, which will affect the charging and discharging of the cell. It may also require the cell to be heated up again for the next use, increasing the energy consumption of the energy storage device.

[0077] For example, the first temperature range is, for instance, [35℃, +∞), and the first value corresponding to the first temperature range is, for instance, 40℃; the second temperature range is, for instance, [10℃, 35℃), and the first value corresponding to the second temperature range is, for instance, 35℃; the third temperature range is, for instance, (-∞, 10℃), and the second value corresponding to the third temperature range is, for instance, 40℃. It is understood that the above temperature ranges and the first temperature threshold are merely specific examples, and this application does not specifically limit the specific division of the temperature ranges or the first temperature threshold corresponding to the temperature ranges.

[0078] In the specific control interaction process, the processor in the energy storage device first determines the ambient temperature outside the energy storage device when determining whether the cooling start condition is met. It then takes the temperature range of the ambient temperature outside the energy storage device as the current temperature range, and then determines the temperature threshold corresponding to the current temperature range as the first temperature threshold. Finally, it determines whether the highest temperature of the battery cell is greater than or equal to the first temperature threshold to determine whether the cooling start condition is met.

[0079] In some embodiments, the energy storage device determines a first temperature threshold corresponding to the current temperature range according to a preset time interval. The preset time interval is a pre-set time interval at which the fan speed and / or the blower speed needs to be adjusted, for example, a preset time interval of 30 minutes. This application does not impose specific limitations on this preset time interval.

[0080] During the specific control interaction process, the processor determines whether the time interval between the last adjustment and the current time has reached the preset time interval. If the preset time interval has reached, the processor determines the temperature range corresponding to the current external ambient temperature (i.e., the current temperature range) and uses the temperature threshold corresponding to the current temperature range as the latest first temperature threshold. The processor then uses the latest first temperature threshold to determine whether the cooling start condition is met. If the preset time interval has not reached, the processor continues to use the previously determined first temperature threshold and uses the previously determined first temperature threshold to determine whether the cooling start condition is met.

[0081] Temperature thresholds are determined according to preset time intervals to avoid rapid changes in adjustment strategies and prevent frequent adjustments to the speed of fans and / or blowers.

[0082] In some embodiments, the thermal management method under the above-described heat dissipation control strategy further includes: responding to ambient temperatures falling within different temperature ranges, controlling a first duty cycle to be at least partially positively correlated with the temperature range. When a cooling start condition is triggered, the period of the electrical signal controlling the first fan is defined as a first period, the duration of controlling the first fan to operate within the first period is defined as a first duration, and the first duty cycle is defined as the ratio of the first duration to the first period.

[0083] In some embodiments of this application, when the cooling start condition is triggered, the electrical signal controlling the first fan is a first PWM signal, the first period represents the period of the first PWM signal, the first duty cycle is represented as D1, D1 = (t1 / T1)*100%, t1 represents the duration of controlling the first fan to run in the first period (i.e., the duration of the first PWM signal being at a high level), T1 represents the first period, and (T1-t1) represents the duration of controlling the first fan to stop in the first period (i.e., the duration of the first PWM signal being at a low level).

[0084] The first condition, that duty cycle is at least partially positively correlated with temperature range, means that each temperature range corresponds to a duty cycle range, and among multiple temperature ranges, at least two temperature ranges satisfy the condition that the lower limit of the duty cycle range for the higher temperature range is greater than the lower limit of the duty cycle range for the lower temperature range. The lower limit of the duty cycle range refers to the minimum value within the duty cycle range.

[0085] For example, the multiple temperature ranges include the aforementioned first temperature range, second temperature range, and third temperature range. The first temperature range is, for example, [35℃, +∞), the second temperature range is, for example, [10℃, 35℃), and the third temperature range is, for example, (-∞, 10℃). The duty cycle corresponding to the first temperature range is, for example, [60%, 90%], the duty cycle corresponding to the second temperature range is, for example, [50%, 90%], and the duty cycle corresponding to the third temperature range is, for example, [60%, 90%]. The first temperature range is the higher temperature range, and the second temperature range is the lower temperature range. The lower limit of the duty cycle corresponding to the first temperature range is greater than the lower limit of the duty cycle corresponding to the second temperature range.

[0086] Under the premise that the first airflow is approximately the same as the total airflow of the fans, the energy storage device controls the first duty cycle to be at least partially positively correlated with the temperature range. During the specific control interaction, the processor, in selecting the duty cycle of the first fan and each fan that adapts to the heat dissipation control strategy and satisfies the first condition, determines the duty cycle range corresponding to the current temperature range as the duty cycle adjustment range. Within this adjustment range, it selects the first fan duty cycle that satisfies the first condition as the first duty cycle, thereby controlling the first duty cycle to be at least partially positively correlated with the temperature range.

[0087] The duty cycle of the internal fan is at least partially positively correlated with the ambient temperature range. When the ambient temperature is not high, the heat dissipation conditions are better. Controlling the internal fan to operate at a lower speed can achieve better heat dissipation on the one hand, and help reduce energy consumption on the other.

[0088] In some embodiments, the thermal management method of this application further includes: controlling a first duty cycle to be positively correlated with the highest temperature of the battery cell in response to the cooling activation condition being triggered. For a definition of the first duty cycle, please refer to the foregoing description.

[0089] The first duty cycle is positively correlated with the highest temperature of the battery cell, meaning that the higher the highest temperature of the battery cell, the larger the first duty cycle and the higher the speed of the first fan; the lower the highest temperature of the first battery cell, the smaller the first duty cycle and the lower the speed of the first fan.

[0090] In some implementations, the first duty cycle is linearly correlated with the highest temperature of the cell, i.e., D1 = k1 * Tc max k1 represents a linear constant between the highest temperature of the battery cell and the first duty cycle, where k1 > 0. In other embodiments, the positive correlation between the first duty cycle and the highest temperature of the battery cell is also set to: the first duty cycle and the highest temperature of the battery cell exhibit a monotonically increasing relationship, a linearly increasing relationship, or a stepwise increasing relationship.

[0091] Under the premise that the initial airflow is approximately the same as the total airflow of the fans, the energy storage device controls the initial duty cycle to be positively correlated with the highest temperature of the battery cell. In the specific control interaction process, while selecting the duty cycle of the first fan and each fan that adapts to the heat dissipation control strategy and meets the first condition, the processor controls the highest temperature of the battery cell to be positively correlated with the initial duty cycle within the adjustment range of the duty cycle.

[0092] The duty cycle of the internal fan is positively correlated with the highest temperature of the battery cell, which helps to quickly reduce the temperature of the battery cell and achieve rapid heat dissipation.

[0093] In some embodiments, the thermal management method of this application further includes: controlling the first air volume and the second air volume to be approximately the same.

[0094] The second air volume is defined as the air volume generated when the second fan is running, and is denoted as Oav. The first air volume and the second air volume are approximately the same, including the following two cases: (1) the first air volume and the second air volume are the same, i.e., Iav = Oav; (2) the ratio of the first air volume to the second air volume is within the second range. For example, the second range is [90%, 110%], i.e., 90% ≤ Iav / Oav ≤ 110%.

[0095] The first and second air volumes are obtained by controlling the duty cycles of the first and second fans. To ensure that the first and second air volumes are approximately the same, air volume tests are first conducted on the first and second fans to determine the air volumes generated by the first and second fans operating at different duty cycles. Based on the air volumes generated by the first fan operating at different duty cycles, the duty cycles of the first and second fans that satisfy the condition that the first and second air volumes are approximately the same are determined (hereinafter referred to as the first fan duty cycle and second fan duty cycle that satisfy the second condition, i.e., the second condition represents that the first and second air volumes are approximately the same). The first fan duty cycle and second fan duty cycle that satisfy the second condition are stored in the energy storage device. In some embodiments, the first and second fans have the same specifications and models, so the first fan duty cycle and second fan duty cycle that satisfy the second condition are equal. In other embodiments, the first and second fans have different specifications and models, so the first fan duty cycle and second fan duty cycle that satisfy the second condition are different.

[0096] In some embodiments, there are multiple sets of first and second fan duty cycles that satisfy the second condition. Each set of first and second fan duty cycles that satisfy the second condition includes two duty cycles: a first fan duty cycle and a second fan duty cycle. These multiple sets of first and second fan duty cycles that satisfy the second condition are used to adapt to the duty cycle requirements of the energy storage device under different operating conditions. When the cooling activation condition is triggered, the energy storage device selects an appropriate heat dissipation control strategy and drives the first and second fans to operate using the first and second fan duty cycles that satisfy the second condition, thereby controlling the first and second airflow to be approximately the same. For the definition of duty cycle, please refer to the foregoing description.

[0097] Understandably, when the cooling activation condition is triggered, since the first airflow and the total fan airflow must be approximately the same, and the first airflow and the second airflow must be approximately the same, when determining the duty cycle to meet these conditions, the duty cycle of the first fan and each individual fan that meets the first condition is first determined, and then the duty cycle of the second fan that meets the second condition is determined, in order to control the duty cycles of the first fan, the second fan, and the individual fans; or, by first determining the duty cycles of the first fan and the second fan that meet the second condition, and then determining the duty cycles of each individual fan that meets the first condition based on the airflow generated by the fans operating at different duty cycles, the duty cycles of the first fan, the second fan, and the individual fans can be controlled.

[0098] Controlling the airflow generated by the internal and external fans to be roughly the same helps to balance the air in the heat exchange unit and reduce the noise generated by the fans.

[0099] The above describes the heat dissipation control strategy when the cooling activation condition is triggered. If the highest temperature of the battery cell is greater than or equal to a first temperature threshold, and the difference between the highest temperature of the battery cell and the ambient temperature outside the energy storage device is greater than a first temperature difference threshold, it indicates that the battery cell temperature is high and cooling is required. A large temperature difference between the inside and outside of the energy storage device satisfies the cooling activation condition. Controlling the operation of the first fan, second fan, and main fan helps accelerate heat dissipation in the energy storage device, reduce the battery cell temperature, and extend battery cell life. The airflow generated by the first fan is approximately the same as the total airflow generated by the main fan to prevent hot air from the rear of the battery module from flowing back to the front of the battery module or to prevent redundant airflow from the first fan, which could reduce heat dissipation efficiency. It is understandable that... Figure 3 As shown, the head of the battery module is a part of the battery module with a fan, and the tail of the battery module is another part arranged opposite to the head of the battery module along the arrangement direction of the battery cells.

[0100] II. Temperature Equalization Control Strategy

[0101] See Figure 6 , Figure 6 This is a flowchart illustrating the thermal management method for an energy storage device provided in other embodiments of this application. For a description of the energy storage device, please refer to the foregoing. Figures 1-4 The relevant description. For example... Figure 6 As shown, the method includes the following steps:

[0102] S301, in response to the triggering of the temperature equalization start condition, controls the operation of the first fan and the fan of the energy storage device, and controls the first air volume to be approximately the same as the total air volume of the fan.

[0103] In some embodiments, the temperature equalization activation condition is set to: a second temperature difference value greater than or equal to a second temperature difference threshold. The second temperature difference value is defined as the difference between the highest temperature and the lowest temperature of the battery cell.

[0104] For the definition of the maximum temperature of the battery cell, please refer to the description of step S201 above, which will not be repeated here.

[0105] The lowest temperature of a battery cell refers to the minimum temperature detected by all the primary temperature sensors in the energy storage device. Taking an energy storage device comprising 12 battery modules, each module containing 24 battery cells and 12 temperature sensors, with the 12 primary temperature sensors distributed across different locations within the battery modules, the 144 cell temperatures form the primary cell temperature set Tc = {Tc1, Tc2, Tc3, ..., Tc...}. 144 The lowest temperature of the battery cell is the minimum value in the first set of battery cell temperatures, and the minimum temperature of the battery cell is min{Tc1, Tc2, Tc3, ..., Tc 144}

[0106] The lowest temperature of the battery cell is expressed as Tc. min Tc min =min{Tc1, Tc2, Tc3,…,Tc N}, where N represents the number of first temperature sensors in the energy storage device.

[0107] The second temperature difference is denoted as ΔT2, where ΔT2 = Tc. max -Tc min For the definitions of the first air volume and the total fan air volume, please refer to the description in step S201 above, which will not be repeated here.

[0108] The second temperature difference threshold is a threshold used to determine whether the conditions for opening the temperature equalization switch are met. For example, the second temperature difference threshold is 5°C. This application does not impose specific limitations on the second temperature difference threshold.

[0109] During the specific control interaction process, the processor in the energy storage device determines the maximum and minimum cell temperatures and calculates the difference between them as the second temperature difference value. It then determines whether the second temperature difference value is greater than or equal to a second temperature difference threshold to determine if the temperature equalization activation condition is met. If the second temperature difference value is greater than or equal to the first temperature difference threshold, it indicates that the temperature equalization activation condition has been triggered. The processor of the energy storage device sends start commands to the first fan and the fans of each battery module to control the operation of the first fan and fans. According to the temperature equalization control strategy, the processor outputs corresponding PWM signals to the first fan and each fan based on the duty cycle of the first fan and the duty cycles of each fan that meet the first condition, so as to control the first airflow to be approximately the same as the total fan airflow. For a description of the duty cycle of the first fan and the duty cycles of each fan that meet the first condition, please refer to the description of step S201 above; it will not be repeated here.

[0110] In some embodiments, the thermal management method under the above-described temperature equalization control strategy further includes: controlling the second duty cycle to be positively correlated with the second temperature difference value. When the temperature equalization activation condition is triggered, the period of the electrical signal controlling the first fan is defined as the second period, the duration of controlling the first fan to operate within the second period is defined as the second duration, and the second duty cycle is defined as the ratio of the second duration to the second period.

[0111] In some embodiments of this application, when the temperature equalization start condition is triggered, the electrical signal controlling the first fan is the second PWM signal. The second period represents the period of the second PWM signal, and the second duty cycle is represented as D2, where D2 = (t2 / T2)*100%, t2 represents the duration of controlling the first fan to run in the second period (i.e., the duration of the second PWM signal being at a high level), T2 represents the second period, and (T2-t2) represents the duration of controlling the first fan to stop in the second period (i.e., the duration of the second PWM signal being at a low level).

[0112] The positive correlation between the second duty cycle and the second temperature difference means that the larger the second temperature difference, the larger the second duty cycle and the higher the speed of the first fan; conversely, the smaller the second temperature difference, the smaller the second duty cycle and the lower the speed of the first fan.

[0113] In some embodiments, the second duty cycle and the second temperature difference value are linearly correlated, i.e., D2 = k2 * ΔT2, where k2 represents the linear constant between the second temperature difference value and the second duty cycle, and k2 > 0. In other embodiments, the positive correlation between the second duty cycle and the second temperature difference value is further set to: the second duty cycle and the second temperature difference value exhibit a monotonically increasing relationship, a linearly increasing relationship, or a stepwise increasing relationship.

[0114] Under the premise that the first airflow and the total airflow of the fans are approximately the same, the energy storage device controls the second duty cycle to be positively correlated with the second temperature value. During the specific control interaction, the processor of the energy storage device, in selecting the duty cycle of the first fan and the duty cycles of each fan that adapt to the uniform temperature control strategy and meet the first condition, determines the duty cycle range of the first fan, for example, [60%, 90%]. From the duty cycle range of the first fan, the duty cycle that meets the first condition and is positively correlated with the second temperature difference value is selected as the second duty cycle, thus controlling the second duty cycle to be positively correlated with the second temperature difference value.

[0115] Referring to some of the embodiments described above, under the heat dissipation control strategy, the duty cycle range of the first fan is different or not exactly the same in different temperature ranges. In other embodiments, under the temperature equalization control strategy, the duty cycle range of the first fan is a fixed range in different temperature ranges, and this fixed range is the same as one of the duty cycle ranges of the first fan under the heat dissipation control strategy. For example, under the temperature equalization control strategy, the duty cycle range of the first fan is fixed as [60%, 90%] or [50%, 90%]. In still other embodiments, under the temperature equalization control strategy, the duty cycle range of the first fan is different in different temperature ranges, and corresponds to the same duty cycle range of the first fan under the heat dissipation control strategy.

[0116] The duty cycle of the internal fan is positively correlated with the temperature difference, which helps to quickly reduce the temperature difference between the cells, thereby shortening the working time of the internal fan and the main fan, and reducing the energy consumption of the energy storage device.

[0117] In some embodiments, the thermal management method in the uniform temperature control mode further includes: controlling a third duty cycle that is positively correlated with the temperature of the battery module. When the uniform temperature activation condition is triggered, the period of the electrical signal controlling the fan is defined as the third cycle, the duration of fan operation within the third cycle is defined as the third duration, and the third duty cycle is defined as the ratio of the third duration to the third cycle. The temperature of the battery module is defined as: the highest temperature of the cells in the battery module, or the average temperature of the cells in the cell module.

[0118] In some embodiments of this application, when the temperature equalization start condition is triggered, the electrical signal controlling the fan is a third PWM signal. The third cycle represents the period of the third PWM signal, and the third duty cycle is represented as D3, where D3 = (t3 / T3)*100%, t3 represents the duration of fan operation in the third cycle (i.e., the duration of the third PWM signal being at a high level), T3 represents the third cycle, and (T3-t3) represents the duration of fan stoppage in the third cycle (i.e., the duration of the third PWM signal being at a low level).

[0119] The temperature of the battery module is denoted as Tb, where Tb = max{Tc} b1 Tc b2Tc b3 , ..., Tc bn},or n represents the number of first temperature sensors in a battery module. Taking 12 first temperature sensors distributed in different locations within a battery module as an example, the processor acquires data or electrical signals transmitted from the 12 first temperature sensors, calculates the temperatures of the 12 battery cells, and determines that the 12 cell temperatures form the second cell temperature set Tc. b ={Tc b1 Tc b2 Tc b3 , ..., Tc b12 Further calculations show that the temperature of the battery module is max{Tc}. b1 Tc b2 Tc b3 , ..., Tc b12},or

[0120] The third duty cycle is positively correlated with the battery module temperature, meaning that the higher the battery module temperature, the larger the third duty cycle; and the lower the battery module temperature, the smaller the third duty cycle. In other words, when the temperature equalization condition is triggered, the higher the battery module temperature, the higher the fan speed on the battery module, and the lower the battery module temperature, the lower the fan speed on the battery module.

[0121] In some implementations, the third duty cycle is linearly correlated with the temperature of the battery module, i.e., D3 = k3 * Tb, where k3 represents a linear constant between the temperature of the battery module and the third duty cycle, and k3 > 0. In other implementations, the positive correlation between the third duty cycle and the temperature of the battery module is further set to: the third duty cycle and the temperature of the battery module exhibit a monotonically increasing relationship, a linearly increasing relationship, or a stepwise increasing relationship.

[0122] Under the premise that the first airflow is approximately the same as the total airflow of the fans, the energy storage device controls the third duty cycle to be positively correlated with the temperature of the battery module. In the specific control interaction process, for each fan in the battery module, the processor of the energy storage device calculates the temperature of each cell in the battery module while selecting the first fan duty cycle and the duty cycles of each fan that meet the first condition and adapt to the temperature equalization control strategy. This forms a second set of cell temperatures. Based on the second set of cell temperatures, the temperature of the battery module is determined. The fan duty cycle that meets the first condition and is positively correlated with the temperature of the battery module is selected as the third duty cycle, thus controlling the third duty cycle to be positively correlated with the temperature of the battery module.

[0123] The fan's duty cycle is positively correlated with the battery module's temperature, which helps to quickly reduce the temperature difference between battery modules, thereby shortening the fan's operating time.

[0124] In some specific embodiments, the above-mentioned control of the third duty cycle being positively correlated with the temperature of the battery module is set as follows: in response to the temperature of the first battery module being higher than the average temperature of the battery module, the third duty cycle is controlled to increase; in response to the temperature of the second battery module being lower than the average temperature of the battery module, the third duty cycle is controlled to decrease.

[0125] The average temperature of the battery module is expressed as Tb. a , Tb k The temperature of the k-th battery module is represented by , and m represents the total number of battery modules.

[0126] During the specific control interaction process, the processor of the energy storage device calculates the average temperature of the battery modules based on the temperature of each battery module in the energy storage device. If the temperature of the first battery module is higher than the average temperature of the battery modules, the energy storage device extends the high-level duration of the third PWM signal output to the fan of the first battery module to increase the third duty cycle; if the temperature of the second battery module is lower than the average temperature of the battery modules, the energy storage device shortens the high-level duration of the third PWM signal output to the fan of the second battery module to decrease the third duty cycle.

[0127] When the battery module temperature is higher than its average temperature, the fan duty cycle is increased, and the fan speed is increased to accelerate heat dissipation from the hot battery module. When the battery module temperature is lower than its average temperature, the fan duty cycle is decreased to maintain a constant total airflow.

[0128] In some specific embodiments, the above-mentioned control of the third duty cycle being positively correlated with the temperature of the battery module is further configured such that, in response to the highest temperature and the lowest temperature of the battery cell belonging to the same battery module in the energy storage device, the control of the third duty cycle remains unchanged.

[0129] For the definitions of the maximum and minimum temperatures of the battery cell, please refer to the descriptions of steps S201 and S301 above, which will not be repeated here.

[0130] The highest and lowest temperatures of a battery cell belong to the same battery module, meaning that the maximum and minimum values ​​in the aforementioned first set of battery cell temperatures are the temperatures monitored by the first temperature sensor in the same battery module.

[0131] During the specific control interaction process, after the processor of the energy storage device determines the first set of cell temperatures, it determines whether the maximum temperature and the minimum temperature in the first set of cell temperatures are the same temperatures monitored by the first temperature sensor in the same battery module. If the maximum temperature and the minimum temperature in the first set of cell temperatures are the same temperatures monitored by the first temperature sensor in the same battery module, after determining the second duty cycle, the energy storage device determines the duty cycle of each fan that satisfies the first condition with the second duty cycle, as the third duty cycle, and controls the third duty cycle to remain unchanged.

[0132] In some embodiments, the thermal management method further includes controlling or maintaining the second fan off.

[0133] When the temperature equalization activation condition is triggered, controlling or keeping the second fan off is beneficial for saving energy consumption of the energy storage equipment.

[0134] In some embodiments, the thermal management method under the above-described heat dissipation control strategy and temperature equalization control strategy further includes: controlling or maintaining the second fan off in response to the cooling start condition not being triggered and the temperature equalization start condition being triggered.

[0135] In some embodiments, the cooling activation condition is set to: the highest temperature of the battery cell is less than a first temperature threshold, or the first temperature value is less than a first temperature difference threshold.

[0136] For the definitions of the cell's maximum temperature, first temperature threshold, first temperature value, and first temperature difference threshold, please refer to the description of step S201 above.

[0137] For the definition of the conditions for triggering the temperature equalization start, please refer to the description of step S301 above.

[0138] When the cooling activation condition is not triggered but the temperature equalization activation condition is triggered, controlling or keeping the second fan off is beneficial for saving energy.

[0139] The above describes the control strategy (i.e., the temperature equalization control strategy) when the temperature equalization activation condition is triggered. If the difference between the highest and lowest temperatures of a battery cell exceeds the second temperature difference threshold, it indicates a significant temperature difference between the cells, satisfying the temperature equalization activation condition. Controlling the operation of the first fan and the main fan helps accelerate fluid circulation within the energy storage device, balances the temperature between battery modules, reduces the temperature difference between battery modules, and promotes consistent charging and discharging of the battery modules. Controlling the airflow generated by the first fan to be approximately the same as the total airflow generated by the main fan prevents hot air from flowing back from the rear of the battery module to the front of the battery module or causing redundancy in the airflow of the first fan, which would reduce heat dissipation efficiency.

[0140] III. Heating Control Strategy

[0141] See Figure 7 , Figure 7 This is a flowchart illustrating a thermal management method for an energy storage device provided in some embodiments of this application. For a description of the energy storage device, please refer to the foregoing. Figures 1-5 The relevant description. For example... Figure 7 As shown, the method includes the following steps:

[0142] S401, in response to the heating start condition being triggered, controls the first fan, the fan and the heater of the energy storage device to operate, controls or keeps the second fan of the energy storage device off, and controls the first air volume to be approximately the same as the total air volume of the fan.

[0143] In some embodiments, the heating activation condition is set to: the minimum temperature of the battery cell is less than a second temperature threshold.

[0144] For the definition of the minimum temperature of the battery cell, please refer to the introduction of step S301 above, which will not be repeated here.

[0145] For the definitions of the first air volume and the total fan air volume, please refer to the introduction of step S201 above, which will not be repeated here.

[0146] The second temperature threshold is a threshold used to determine whether the heating start-up conditions are met. For example, the second temperature threshold is 10°C. This application does not impose specific limitations on the second temperature threshold.

[0147] During the specific control interaction process, after acquiring data or electrical signals from the first sensor, the processor in the energy storage device calculates the first set of cell temperatures. The minimum value in this set is determined as the lowest temperature of the cell. The processor then checks if the lowest temperature is less than a second temperature threshold to determine if the heating start-up condition is met. If the lowest temperature is less than the second temperature threshold, the heating start-up condition is triggered. The processor then sends start commands to the first fan, the main fan, and the heater to control their operation. According to the heating control strategy, the processor outputs corresponding PWM signals to the first fan and each fan, ensuring that the first airflow is approximately equal to the total fan airflow. For a description of the first fan duty cycle and the duty cycles of each fan that meet the first condition, please refer to the description of step S201 above; it will not be repeated here.

[0148] In some embodiments, the thermal management method further includes: controlling a fourth duty cycle to be negatively correlated with the lowest temperature of the battery cell. The period of the electrical signal controlling the first fan when the heating start-up condition is triggered is defined as the fourth cycle, the duration of controlling the first fan to operate within the fourth cycle is defined as the fourth duration, and the fourth duty cycle is defined as the ratio of the fourth duration to the fourth cycle.

[0149] In some embodiments of this application, when the heating start-up condition is triggered, the electrical signal controlling the first fan is a fourth PWM signal. The fourth cycle represents the period of the fourth PWM signal, and the fourth duty cycle is represented as D4, where D4 = (t4 / T4)*100%, t4 represents the duration of controlling the first fan to run in the fourth cycle (i.e., the duration of the fourth PWM signal being at a high level), T4 represents the fourth cycle, and (T4-t4) represents the duration of controlling the first fan to stop in the fourth cycle (i.e., the duration of the fourth PWM signal being at a low level).

[0150] The fourth duty cycle is negatively correlated with the lowest temperature of the battery cell, meaning that the higher the lowest temperature of the battery cell, the smaller the fourth duty cycle; and the lower the lowest temperature of the battery cell, the larger the fourth duty cycle. In other words, when the heating conditions are met, the lower the temperature of the battery cell, the higher the speed of the first fan, and the higher the temperature of the battery cell, the lower the speed of the first fan.

[0151] In some implementations, the fourth duty cycle is linearly correlated with the minimum temperature of the battery cell, i.e., D4 = k4 * Tcmin, where k4 represents a linear constant between the minimum temperature of the battery cell and the fourth duty cycle, and k4 < 0. In other implementations, the negative correlation between the fourth duty cycle and the minimum temperature of the battery cell also includes: a monotonically decreasing relationship, a linear decreasing relationship, or a step-decreasing relationship between the fourth duty cycle and the minimum temperature of the battery cell.

[0152] Under the premise that the first airflow and the total airflow of the fans are approximately the same, the energy storage device controls the fourth duty cycle to be negatively correlated with the lowest temperature of the battery cell. During the specific control interaction, the processor of the energy storage device, in selecting the duty cycle of the first fan and each fan that adapts to the heating control strategy and meets the first condition, determines the duty cycle range of the first fan, for example, [50%, 90%]. From the duty cycle range of the first fan, the duty cycle that meets the first condition and has a negative correlation with the lowest temperature of the battery cell is selected as the fourth duty cycle, thus controlling the fourth duty cycle to be negatively correlated with the lowest temperature of the battery cell.

[0153] In some embodiments of this application, under the heating control strategy, the duty cycle range of the first fan is fixed to a value, such as [60%, 90%] or [50%, 90%].

[0154] The duty cycle of the internal fan is negatively correlated with the lowest temperature of the battery cell, which helps to quickly increase the temperature of the battery module.

[0155] The above describes the control strategy (i.e., heating control strategy) when the heating activation condition is triggered. If the cell's minimum temperature is below the second temperature threshold, it indicates that the cell temperature is low and requires heating. Once the heating activation condition is met, the processor controls the operation of the heater, internal fan, and air fan in the heat exchanger, which helps to rapidly raise the internal temperature of the energy storage device.

[0156] In some embodiments of this application, the above-mentioned heat dissipation control strategy, temperature equalization control strategy and heating control strategy are independent control strategies, and the energy storage device executes the above-mentioned heat dissipation control strategy, temperature equalization control strategy and heating control strategy in parallel.

[0157] During the parallel execution of the above-mentioned heat dissipation control strategy, temperature equalization control strategy, and heating control strategy, the energy storage device also executes the above-mentioned heat dissipation control strategy, temperature equalization control strategy, and heating control strategy according to the following control principles:

[0158] Control Principle 1: When there is a conflict between the two control strategies, the air volume of the fan and blower shall be controlled according to the principle of maximizing the air volume demand.

[0159] Based on control principle 1, in some embodiments, the thermal management method under the above heat dissipation control strategy and the temperature equalization control strategy further includes: in response to both the cooling start condition and the temperature equalization start condition being triggered, controlling the first air volume to the maximum value that satisfies the cooling start condition and the temperature equalization start condition.

[0160] In the specific control interaction process, when both the cooling start condition and the temperature equalization start condition are met or triggered, the processor of the energy storage device determines the duty cycle of the first fan under the cooling control strategy and the duty cycle of the first fan under the temperature equalization strategy according to the heat dissipation control strategy and the temperature equalization control strategy described above, respectively, and selects the larger duty cycle of the first fan as the duty cycle required to control the operation of the first fan.

[0161] When both cooling activation and temperature equalization activation conditions are triggered, controlling the airflow of the internal fan to the maximum value that satisfies both conditions helps to quickly dissipate heat and / or equalize temperature, thus shortening the operating time of the internal fan and the main fan.

[0162] In some embodiments, the thermal management method further includes: in response to both the heating start condition and the temperature equalization start condition being triggered, controlling the first air volume to the maximum value that satisfies the heating start condition and the temperature equalization start condition.

[0163] During the specific control interaction process, when both the heating start condition and the temperature equalization start condition are triggered or met, the processor of the energy storage device determines the duty cycle of the first fan under the temperature equalization control strategy and the duty cycle of the first fan under the heating control strategy according to the temperature equalization control strategy and the heating control strategy described above. It then selects the larger duty cycle of the first fan as the duty cycle required to control the first fan, so as to control the first air volume to the maximum value that satisfies both the heating start condition and the temperature equalization start condition.

[0164] When both heating and temperature equalization conditions are triggered, controlling the airflow of the internal fan to the maximum value that satisfies both conditions helps to quickly raise the temperature and shorten the operating time of the fan and ventilator.

[0165] Understandably, under the above control principle 1, the first air volume is kept approximately the same as the total air volume of the fan.

[0166] Control Principle 2: If all conditions for exiting control are met, shut down the fan and other fans.

[0167] Based on control principle 2, in some embodiments, the thermal management method further includes: controlling the first fan, the second fan, and the fan to shut down in response to the triggering of a cooling shutdown condition and a uniform temperature shutdown condition, or in response to the triggering of a uniform temperature shutdown condition and a heating shutdown condition.

[0168] In some embodiments, the cooling shutdown condition is set as follows: the highest temperature of the battery cell is less than a third temperature threshold, and the third temperature threshold is less than a first temperature threshold; or, the first temperature difference value is less than the third temperature difference threshold, and the third temperature difference threshold is less than the first temperature difference threshold. The temperature equalization shutdown condition includes: the second temperature difference value is less than a fourth temperature difference threshold, and the fourth temperature difference threshold is less than the second temperature difference threshold. The heating shutdown condition includes: the lowest temperature of the battery cell is greater than a fourth temperature threshold, and the fourth temperature threshold is greater than the second temperature threshold.

[0169] For the definitions of the maximum temperature of the battery cell, the first temperature threshold, and the first temperature difference threshold, please refer to the description of step S201 above, which will not be repeated here.

[0170] The third temperature threshold and the third temperature difference threshold are thresholds used to determine whether the cooling shutdown conditions are met. For example, the third temperature difference threshold is 4°C. This application does not impose specific limitations on the third temperature threshold and the third temperature difference threshold.

[0171] When the ambient temperature range is divided into multiple temperature zones, each corresponding to a different first temperature threshold, and also to different third temperature thresholds, meaning the third temperature threshold differs depending on the ambient temperature range. Therefore, setting appropriate cell temperature thresholds prevents the energy storage device from shutting down its cooling system when the internal and external temperature differences are unsuitable, thus avoiding repeated start-stop cycles of fans and other cooling devices.

[0172] In some implementations, the multiple temperature ranges include a first temperature range, a second temperature range, and a third temperature range, wherein the temperature in the first temperature range is higher than the temperature in the second temperature range, and the temperature in the second temperature range is higher than the temperature in the third temperature range. The third temperature threshold includes a fourth value corresponding to the first temperature range, a fifth value corresponding to the second temperature range, and a sixth value corresponding to the third temperature range; the fourth value is greater than the fifth value, and the sixth value is greater than the fifth value.

[0173] For example, the first temperature range is [35℃, +∞), and the fourth value corresponding to the first temperature range is 38℃; the second temperature range is [10℃, 35℃), and the fifth value corresponding to the second temperature range is 30℃; the third temperature range is (-∞, 10℃), and the sixth value corresponding to the third temperature range is 38℃.

[0174] For the definitions of the second temperature difference value and the second temperature difference threshold, please refer to the description of step S301 above, which will not be repeated here.

[0175] The fourth temperature difference threshold is a threshold used to determine whether the uniform temperature shut-off condition is met. For example, the fourth temperature difference threshold is 4°C. This application does not impose specific limitations on the fourth temperature difference threshold.

[0176] For the definition of the minimum temperature of the battery cell, please refer to the introduction of step 301 above; for the definition of the second temperature threshold, please refer to the introduction of step S402 above; it will not be repeated here.

[0177] The fourth temperature threshold is a threshold used to determine whether the heating shutdown condition is met. For example, the fourth temperature threshold is 15°C. This application does not impose specific limitations on the fourth temperature threshold.

[0178] During the specific control interaction process, the processor of the energy storage device acquires data or electrical signals from temperature sensors, calculates the cell temperature and the external ambient temperature, determines a first set of cell temperatures, identifies the maximum value in the first set as the highest cell temperature, and the minimum value as the lowest cell temperature. The difference between the highest cell temperature and the external ambient temperature is calculated as the first temperature difference value. The difference between the maximum and minimum values ​​in the first set of cell temperatures is calculated as the second temperature difference value. The processor then determines whether the highest cell temperature is less than a third temperature threshold, whether the first temperature difference value is less than the third temperature difference threshold to determine if the cooling shutdown condition is met; whether the second temperature difference value is less than a fourth temperature difference threshold to determine if the temperature equalization shutdown condition is met; and whether the lowest cell temperature is greater than the fourth temperature threshold to determine if the heating shutdown condition is met. If the highest temperature of the battery cell is less than the third temperature threshold, or the first temperature difference is less than the third temperature difference threshold, the cooling shutdown condition is met; if the second temperature difference is less than the fourth temperature difference threshold, the temperature equalization shutdown condition is met; if the lowest temperature of the battery cell is greater than the fourth temperature threshold, the heating shutdown condition is met. When both the cooling shutdown condition and the temperature equalization shutdown condition are met, or both the temperature equalization shutdown condition and the heating shutdown condition are met, the processor of the energy storage device sends a stop command to the first fan, the second fan, and the fans of each battery module to control the first fan, the second fan, and the fans to shut down.

[0179] When both shutdown conditions are triggered, controlling the fan and blower to shut down helps reduce the energy consumption of energy storage devices.

[0180] See Figure 8 , Figure 8 This is a schematic diagram of an energy storage device provided in an embodiment of this application. The energy storage device 50 includes one or more processors 501 and a memory 502. The memory 502 is connected to one or more processors 501, for example, via a bus.

[0181] Processor 501 is configured to support the energy storage device in performing the corresponding functions in the methods described in the above method embodiments. Processor 501 may be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The aforementioned PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), generic array logic (GAL), or any combination thereof.

[0182] Memory 502 is used to store program code, etc. Memory may include volatile memory (VM), such as random access memory (RAM); memory 502 may also include non-volatile memory (NVM), such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); memory may also include combinations of the above types of memory.

[0183] The memory 502 can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the thermal management method of the energy storage device in the embodiments of this application. The processor 501 executes various functional applications and data processing of the thermal management method of the energy storage device by running the non-volatile software programs, instructions, and modules stored in the memory, thereby realizing the function of the thermal management method of the energy storage device provided in the above method embodiments.

[0184] The memory 502 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function. The data storage area may store data created based on the use of the thermal management method of the energy storage device.

[0185] One or more modules are stored in a memory. When executed by one or more processors, they perform the thermal management method of the energy storage device in any of the above method embodiments. For example, they perform the method steps described in the above method embodiments to realize the functions of the modules described in the above device embodiments.

[0186] This application also provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the method as described in the foregoing embodiments.

[0187] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0188] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A thermal management method for an energy storage device, characterized in that, The thermal management method for the energy storage device is applied to the energy storage device, which includes: Multiple battery modules, each of which includes a fan and multiple battery cells; Multiple temperature sensors, including a first temperature sensor and a second temperature sensor, wherein the first temperature sensor is used to monitor the temperature of the battery cell and the second temperature sensor is used to monitor the ambient temperature outside the energy storage device; A heat exchanger includes a first fan, a heat exchange unit, and a second fan. The heat exchanger is used to exchange heat between the fluid inside the energy storage device and the fluid outside the energy storage device. The method includes: in response to a cooling activation condition being triggered, controlling the first fan, the second fan, and the general fan to operate, and controlling the first airflow to be approximately the same as the total airflow of the general fan; wherein... The cooling activation conditions include: the highest temperature of the battery cell is greater than or equal to a first temperature threshold, and the first temperature difference value is greater than or equal to a first temperature difference threshold. The first temperature difference value is defined as the difference between the highest temperature of the battery cell and the ambient temperature; The first air volume is defined as the air volume generated by the operation of the first fan, and the total fan air volume is defined as the sum of all air volumes generated by the operation of the fans.

2. The thermal management method according to claim 1, characterized in that, The ambient temperature is located in different temperature ranges, and the first temperature threshold is different for each range.

3. The thermal management method according to claim 2, characterized in that, The temperature range includes a first temperature range, a second temperature range, and a third temperature range, wherein the temperature in the first temperature range is higher than the temperature in the second temperature range, and the temperature in the second temperature range is higher than the temperature in the third temperature range. The first temperature threshold includes: a first value corresponding to the first temperature range, a second value corresponding to the second temperature range, and a third value corresponding to the third temperature range; Wherein, the first value is greater than the second value, and the third value is greater than the second value.

4. The thermal management method according to claim 2 or 3, characterized in that, Also includes: In response to the ambient temperature falling within different temperature ranges, the first duty cycle is controlled to be at least partially positively correlated with the temperature range; wherein... The period of the electrical signal controlling the first fan when the cooling start condition is triggered is defined as the first period, the duration of the first fan operation within the first period is defined as the first duration, and the first duty cycle is defined as the ratio of the first duration to the first period.

5. The thermal management method according to any one of claims 1-4, characterized in that, Also includes: In response to the cooling activation condition being triggered, the first duty cycle is controlled to be positively correlated with the highest temperature of the battery cell; wherein... The period of the electrical signal controlling the first fan when the cooling start condition is triggered is defined as the first period, the duration of the first fan operation within the first period is defined as the first duration, and the first duty cycle is defined as the ratio of the first duration to the first period.

6. The thermal management method according to any one of claims 2-5, characterized in that, Also includes: The first temperature threshold corresponding to the current temperature range is determined according to a preset time interval.

7. The thermal management method according to any one of claims 1-6, characterized in that, Also includes: The first and second air volumes are controlled to be approximately the same. The second air volume is defined as the air volume generated by the operation of the second fan.

8. The thermal management method according to any one of claims 1-7, characterized in that, Also includes: In response to the temperature equalization activation condition being triggered, the first fan and the main fan are controlled to operate, and the first airflow is controlled to be approximately the same as the total airflow of the main fan; wherein, The temperature equalization activation condition includes: the second temperature difference value is greater than or equal to the second temperature difference threshold; The second temperature difference value is defined as the difference between the highest temperature of the battery cell and the lowest temperature of the battery cell.

9. The thermal management method according to claim 8, characterized in that, Also includes: The second duty cycle is controlled to be positively correlated with the second temperature difference value; wherein, The period of the electrical signal controlling the first fan when the temperature equalization start condition is triggered is defined as the second period, the duration of the first fan being controlled to operate during the second period is defined as the second duration, and the second duty cycle is defined as the ratio of the second duration to the second period.

10. The thermal management method according to claim 8 or 9, characterized in that, Also includes: In response to both the cooling start condition and the temperature equalization start condition being triggered, the first airflow is controlled to be the maximum value that satisfies both the cooling start condition and the temperature equalization start condition. and / or In response to the cooling start condition not being triggered and the temperature equalization start condition being triggered, the second fan is controlled or kept off.

11. The thermal management method according to any one of claims 8-10, characterized in that, Also includes: The third duty cycle is controlled to be positively correlated with the temperature of the battery module; wherein... The period of the electrical signal controlling the fan when the temperature equalization start condition is triggered is defined as the third period, the duration of controlling the fan to run in the third period is defined as the third duration, and the third duty cycle is defined as the ratio of the third duration to the third period. The temperature of the battery module is defined as: i) the highest temperature of the battery cell in the battery module, or ii) the average temperature of the battery cell in the battery cell module.

12. The thermal management method according to claim 11, characterized in that, The control of the third duty cycle is positively correlated with the temperature of the battery module, including: In response to the temperature of the first battery module being higher than the average temperature of the battery module, the third duty cycle is controlled to increase; In response to the temperature of the second battery module being lower than the average temperature of the battery modules, the third duty cycle is controlled to decrease; wherein... The average temperature of the battery module is defined as the average temperature of all battery modules.

13. The thermal management method according to claim 11 or 12, characterized in that, The control of the third duty cycle being positively correlated with the temperature of the battery module also includes: In response to the fact that the highest temperature and the lowest temperature of the battery cell in the energy storage device belong to the same battery module, the third duty cycle is controlled to remain unchanged.

14. The thermal management method according to any one of claims 1-13, characterized in that, The heat exchanger further includes a heater, and the method further includes: In response to the heating start condition being triggered, the system controls the operation of the first fan, the general fan, and the heater, controls or keeps the second fan off, and controls the first airflow to be approximately the same as the total airflow of the general fan; wherein, The heating activation condition includes: the lowest temperature of the battery cell is less than the second temperature threshold.

15. The thermal management method according to claim 14, characterized in that, Also includes: The fourth duty cycle is negatively correlated with the lowest temperature of the battery cell; wherein, The period of the electrical signal controlling the first fan when the heating start condition is triggered is defined as the fourth period, the duration of controlling the first fan to operate in the fourth period is defined as the fourth duration, and the fourth duty cycle is defined as the ratio of the fourth duration to the fourth period.

16. The thermal management method according to claim 14 or 15, characterized in that, Also includes: In response to both the heating start condition and the temperature equalization start condition being triggered, the first airflow is controlled to be the maximum value satisfying both the heating start condition and the temperature equalization start condition; wherein, The temperature equalization activation condition includes: the second temperature difference value is greater than or equal to the second temperature difference threshold; The second temperature difference value is defined as the difference between the highest temperature of the battery cell and the lowest temperature of the battery cell.

17. The thermal management method according to any one of claims 1-16, characterized in that, Also includes: In response to both the cooling shutdown condition and the temperature equalization shutdown condition being triggered, or in response to both the temperature equalization shutdown condition and the heating shutdown condition being triggered, the first fan, the second fan, and the main fan are controlled to shut down; wherein, The cooling shutdown conditions include: i) The highest temperature of the battery cell is less than a third temperature threshold, and the third temperature threshold is less than the first temperature threshold, or... ii) The first temperature difference value is less than the third temperature difference threshold, and the third temperature difference threshold is less than the first temperature difference threshold; The temperature equalization shutdown condition includes: the second temperature difference value is less than the fourth temperature difference threshold, and the fourth temperature difference threshold is less than the second temperature difference threshold. The heating shutdown conditions include: the lowest temperature of the battery cell is greater than a fourth temperature threshold, and the fourth temperature threshold is greater than a second temperature threshold.

18. A thermal management method for an energy storage device, characterized in that, The thermal management method for the energy storage device is applied to the energy storage device, which includes: Multiple battery modules, each of which includes a fan and multiple battery cells; Multiple temperature sensors, including a first temperature sensor and a second temperature sensor, wherein the first temperature sensor is used to monitor the temperature of the battery cell and the second temperature sensor is used to monitor the ambient temperature outside the energy storage device; A heat exchanger includes a first fan, a heat exchange unit, and a second fan. The heat exchanger is used to exchange heat between the fluid inside the energy storage device and the fluid outside the energy storage device. The method includes: in response to the uniform temperature activation condition being triggered, controlling the first fan and the general fan to operate, and controlling the first airflow to be approximately the same as the total airflow of the general fan; wherein, The temperature equalization activation condition includes: the second temperature difference value is greater than or equal to the second temperature difference threshold; The second temperature difference value is defined as the difference between the highest temperature of the battery cell and the lowest temperature of the battery cell; The first air volume is defined as the air volume generated by the operation of the first fan, and the total air volume of the fan is defined as the sum of all air volumes generated by the operation of the fan.

19. The thermal management method according to claim 18, characterized in that, Also includes: Control or maintain the second fan off.

20. An energy storage device, characterized in that, include: Multiple battery modules, each of which includes a fan and multiple battery cells; Multiple temperature sensors, including a first temperature sensor and a second temperature sensor, wherein the first temperature sensor is used to monitor the temperature of the battery cell and the second temperature sensor is used to monitor the ambient temperature outside the energy storage device; A heat exchanger includes a first fan, a heat exchange unit, and a second fan. The heat exchanger is used to exchange heat between the fluid inside the energy storage device and the fluid outside the energy storage device. The energy storage device is used to perform the method as described in any one of claims 1-17, or the method as described in claim 18 or 19.

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