A temperature control method for energy storage system and energy storage system

Abstract

The present application provides a temperature control method for an energy storage system and an energy storage system, the temperature control method comprising: starting a temperature control device and an air supply device, and obtaining a first temperature at an air inlet of an air supply channel and a second temperature at an air outlet of the air supply channel; judging whether the first temperature is within a first preset temperature range, and whether the second temperature is within a second preset temperature range; if one of the above conditions is not met, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range, and the second temperature is within the second preset temperature range; when the first temperature is within the first preset temperature range, and the second temperature is within the second preset temperature range, locking the temperature control device to a current output power; adjusting the output power of the temperature control device according to the detected first temperature and second temperature is beneficial to improving the detection accuracy of the battery pack temperature, and further beneficial to improving the control accuracy of the battery pack temperature.

Description

Technical Field

[0001] The present application belongs to the technical field of energy storage systems, and in particular, relates to a temperature control method of an energy storage system and an energy storage system. Background Art

[0002] The battery pack temperature control system in the existing energy storage system has significant technical defects, which seriously restricts the improvement of the overall performance of the energy storage system. The current temperature control system cannot accurately control the temperature of the battery pack, making it difficult for the battery pack to work in a suitable temperature environment.

[0003] Therefore, how to improve the control accuracy of the battery pack temperature is a problem that technicians in this field currently need to solve. Summary of the invention

[0004] The purpose of the present application is to provide a temperature control method and an energy storage system for an energy storage system, aiming to solve the problem of low control accuracy of battery pack temperature.

[0005] A first aspect of an embodiment of the present application provides a temperature control method for an energy storage system, wherein the energy storage system includes a temperature control device, a battery pack, and an air supply device, wherein the battery pack includes a plurality of cells arranged at intervals, the temperature control device is used to control the temperature of the battery pack, and the air supply device is used to supply air to an air supply channel between the plurality of cells; the temperature control method includes:

[0006] Starting the temperature control device and the air supply device, and obtaining a first temperature of an air inlet of the air supply channel and a second temperature of an air outlet of the air supply channel;

[0007] Determining whether the first temperature is within a first preset temperature range, and whether the second temperature is within a second preset temperature range;

[0008] If the temperature of the air inlet or the air outlet is not within the preset range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range and the second temperature is within the second preset temperature range;

[0009] When the first temperature is within a first preset temperature range and the second temperature is within a second preset temperature range, the temperature control device is locked to a current output power.

[0010] In some embodiments of the present application, if the first temperature is not within a first preset temperature range, and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device includes:

[0011] Setting the temperature control device to different output powers, and obtaining the first temperature and the second temperature under the different output power conditions;

[0012] According to the different output powers and their corresponding first temperatures and second temperatures, a first correspondence table of the first temperature, the second temperature and the output power is obtained, and the first correspondence table is used to provide the required output power value in adjusting the output power of the temperature control device.

[0013] In some embodiments of the present application, if the first temperature is not within a first preset temperature range and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range and the second temperature is within the second preset temperature range includes:

[0014] When the number of times the output power of the temperature control device is adjusted is greater than the first preset number, the air supply speed of the air supply device is increased.

[0015] In some embodiments of the present application, if the first temperature is not within a first preset temperature range and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range and the second temperature is within the second preset temperature range includes:

[0016] When the number of times the output power of the temperature control device is adjusted is equal to a second preset number of times, adjusting the air supply speed of the air supply device to a maximum wind speed; the second preset number of times is greater than the first preset number of times;

[0017] When the number of times the output power of the temperature control device is adjusted is greater than a second preset number, a shutdown alarm is issued.

[0018] In some embodiments of the present application, when the first temperature is within a first preset temperature range and the second temperature is within a second preset temperature range, locking the temperature control device to a current output power includes:

[0019] Acquiring a third temperature of each of the battery cells, and determining whether the third temperature is within a third preset temperature range;

[0020] If the third temperature is outside the third preset temperature range, adjusting the air supply speed of the air supply device until the third temperature is within the third preset temperature range;

[0021] When the third temperature is within the third preset temperature range, the air supply device is locked to the current first air supply speed.

[0022] In some embodiments of the present application, if the third temperature is outside the third preset temperature range, adjusting the air supply speed of the air supply device until the third temperature is within the third preset temperature range includes:

[0023] Setting the air supply device to different air supply speeds, and obtaining the third temperature under the different air supply speed conditions;

[0024] According to the different air supply speeds and their corresponding third temperatures, a second correspondence table between the third temperature and the air supply speed is obtained, and the second correspondence table is used to provide the required air supply speed value in adjusting the air supply speed of the temperature control device.

[0025] In some embodiments of the present application, if the third temperature is outside the third preset temperature range, adjusting the air supply speed of the air supply device until the third temperature is within the third preset temperature range includes:

[0026] When the number of times the air supply speed of the air supply device is adjusted is greater than a third preset number, the temperature control device is adjusted to a different output power.

[0027] In some embodiments of the present application, after locking the air supply device to the current first air supply speed, the method includes:

[0028] Acquire a first sub-temperature of a battery cell with the highest temperature and a second sub-temperature of a battery cell with the lowest temperature among the plurality of battery cells, and calculate a temperature difference between the first sub-temperature and the second sub-temperature;

[0029] Determine whether the temperature difference is within a preset temperature difference range, and if not, adjust the air supply speed of the air supply device until the temperature difference is within the preset temperature difference range;

[0030] When the temperature difference is within the range of the preset temperature difference, the air supply device is locked to the current second air supply speed.

[0031] In some embodiments of the present application, before adjusting the air supply speed of the air supply device until the temperature difference is within the range of the preset temperature difference, the method includes:

[0032] Setting the air supply device to different air supply speeds, and obtaining the first sub-temperature and the second sub-temperature under the different air supply speed conditions;

[0033] According to the different air supply speeds and their corresponding first sub-temperatures and second sub-temperatures, a third correspondence table of the first sub-temperatures, the second sub-temperatures and the air supply speeds is obtained, and the third correspondence table is used to provide the required air supply speed value in adjusting the air supply speed of the temperature control device.

[0034] In some embodiments of the present application, the determining whether the temperature difference is within a preset temperature difference range, and if not, adjusting the air supply speed of the air supply device until the temperature difference is within the preset temperature difference range includes:

[0035] When the number of times the air supply speed of the air supply device is adjusted is greater than a fourth preset number, the process returns to adjusting the first air supply speed of the air supply device.

[0036] In a second aspect, the present application also provides an energy storage system, which includes a temperature control device, a battery pack and an air supply device. The battery pack includes a plurality of battery cells arranged at intervals. The temperature control method of the energy storage system mentioned above is used to control the temperature control device and the air supply device to control the temperature of the battery pack.

[0037] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the above-mentioned temperature control method of an energy storage system and the energy storage system, the temperature control method comprising: starting a temperature control device and an air supply device, and obtaining a first temperature of an air inlet of an air supply channel and a second temperature of an air outlet of an air supply channel; judging whether the first temperature is within a first preset temperature range, and whether the second temperature is within a second preset temperature range; if one of the above conditions is not met, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range, and the second temperature is within the second preset temperature range; when the first temperature is within the first preset temperature range, and the second temperature is within the second preset temperature range, locking the temperature control device to the current output power; detecting the temperatures of the air inlet and the air outlet of the air supply channel, and adjusting the output power of the temperature control device according to the detected first and second temperatures, it is beneficial to improve the detection accuracy of the battery pack temperature, and further beneficial to improve the control accuracy of the battery pack temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the topological structure of an energy storage system provided in one embodiment of the present application;

[0039] Figure 2 A schematic diagram of the steps of a temperature control method for an energy storage system provided in one embodiment of the present application;

[0040] Figure 3 A flow chart of a temperature control method for an energy storage system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0043] It should be understood that the terms "length", "width", "up", "down", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0045] With the transformation of the global energy structure and the rapid development of renewable energy, the importance of energy storage systems as a key link between renewable energy generation and electricity consumption has become increasingly prominent. Energy storage systems can not only balance the supply and demand of the power grid and improve the flexibility and stability of the power system, but also effectively promote the consumption and utilization of renewable energy. Among them, battery energy storage systems have become one of the most promising energy storage technologies with their high energy density, long cycle life and rapid response capabilities. As the core component of the energy storage system, the performance of the battery pack directly affects the efficiency, reliability and economy of the entire system.

[0046] However, the battery pack temperature control system in the existing energy storage system has significant technical defects, which seriously restricts the improvement of the overall performance of the energy storage system. Specifically, the temperature control system has insufficient accuracy in controlling the temperature of the PACK (battery pack) and individual cells inside the battery pack, resulting in uneven temperature distribution between cells and large temperature differences between individual cells. This temperature inconsistency not only accelerates the aging process of the cells and shortens the cycle life of the cells, but also affects the overall safety and consistency of the battery pack, thereby reducing the overall performance and reliability of the energy storage system. In addition, inaccurate temperature control strategies also increase the energy consumption burden of the system, because the system needs to consume additional energy to maintain or adjust the temperature environment inside the battery pack, which directly leads to a decrease in the charging and discharging efficiency of the energy storage system, increases operating costs, and reduces economic benefits.

[0047] Specifically, in the current air-cooled energy storage system, the problem with the temperature control system is that the temperature control of the internal PACK and battery cells is not accurate, and the temperature difference of the single battery cells is large, which affects the cycle life of the battery cells and the overall performance of the energy storage system. In addition, inaccurate temperature control will increase the energy consumption of the system and reduce the charging and discharging efficiency of the system.

[0048] Temperature is an important factor affecting the safe operation of lithium batteries. Reasonable temperature range and temperature distribution consistency are key parameters to ensure the safety and long life of lithium battery energy storage systems. Both operating temperature and temperature consistency have a great impact on its efficiency, life and safety. High temperature environment will accelerate the attenuation rate of lithium batteries and reduce the cycle life of batteries. In severe cases, it will cause thermal runaway and cause safety accidents; low temperature environment is prone to the formation of lithium dendrites, which will affect the battery life and induce safety risks. The inconsistency of battery temperature will also directly lead to a reduction in the service life of the energy storage system. According to research results, when the temperature difference in the battery module reaches 5°C, the life of the battery module is reduced by 30% compared to the life of the module with a temperature difference controlled within 2°C. Therefore, the reasonable design of thermal management of the energy storage system can ensure that the battery operating temperature is within an appropriate range, improve the working environment of the battery, and play an important role in improving battery life, efficiency and system safety and economy.

[0049] Therefore, based on this, the present application improves the temperature control method and energy storage system of the relevant energy storage system.

[0050] See also Figure 1 , Figure 1 A schematic diagram of the topological structure of the energy storage system provided in this embodiment is shown. A temperature control method of an energy storage system in this embodiment, the energy storage system includes a temperature control device, a battery pack and an air supply device, the battery pack includes a plurality of cells arranged at intervals, the temperature control device is used to control the temperature of the battery pack, and the air supply device is used to supply air to the air supply channel between the plurality of cells.

[0051] It should be explained that the temperature control device can be Figure 1In the air conditioner, the air supply device can be Figure 1 The fan in the air inlet can be set at the air outlet.

[0052] In some embodiments, the battery pack includes two rows of battery cells, and an air supply channel is formed between the two rows of battery cells. A plurality of battery cells are arranged at intervals along the direction of the air supply channel to form a row of battery cells.

[0053] Please continue reading Figure 1 Also see Figure 2 , Figure 2 The schematic diagram of the steps of the temperature control method of the energy storage system provided in this embodiment is shown. The temperature control method of the energy storage system in this embodiment includes:

[0054] S100: starting the temperature control device and the air supply device, and obtaining a first temperature of an air inlet of the air supply channel and a second temperature of an air outlet of the air supply channel;

[0055] Specifically, the temperature control device is used to adjust the air temperature in the air supply channel. The air supply device is usually a fan or blower, which is used to suck air from the air inlet and blow it out through the air supply channel. Temperature sensors are installed at both ends of the air supply channel (the air inlet and the air outlet) to measure and obtain the temperature values ​​of these two locations in real time.

[0056] S200: Determine whether the first temperature is within a first preset temperature range, and whether the second temperature is within a second preset temperature range;

[0057] Specifically, the preset temperature range is a temperature interval set according to actual needs, which is used to ensure that the air temperature in the air supply channel remains within an appropriate range. Generally speaking, since the battery pack will dissipate heat when in operation, the first temperature of the air inlet will be lower than the second temperature of the air outlet. By accurately detecting the first temperature and the second temperature, it is helpful to improve the precise control of the temperature of the battery pack.

[0058] S300: If the first temperature is not within a first preset temperature range, and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range, and the second temperature is within the second preset temperature range;

[0059] Specifically, if the temperature of the air inlet or outlet is not within the preset range, the output power of the temperature control device will be adjusted. For example, if the temperature is too low, the cooling power of the air conditioner will be reduced; if the temperature is too high, the cooling power of the air conditioner will be increased. And the process of adjusting the output power of the temperature control device is dynamic. The temperature control device will continue to monitor and adjust its output power until both temperatures meet the preset conditions. More specifically, if one of the above conditions is not met, the output power of the temperature control device will continue to detect whether it meets the conditions after adjusting the output power of the temperature control device, and the above steps will be repeated until the above two conditions are met.

[0060] S400: When the first temperature is within a first preset temperature range and the second temperature is within a second preset temperature range, locking the temperature control device to a current output power.

[0061] Specifically, once the temperature stabilizes within the preset range, the output power of the temperature control device will be locked at the current value to maintain a stable temperature environment. In this way, the system can ensure that the air temperature in the air supply duct is continuously maintained within the required range to meet specific application requirements.

[0062] In the current energy storage system, the temperature of the battery pack is only detected externally, which makes it difficult to ensure accurate detection of the temperature of the battery pack. However, in the present application, by detecting the temperature of the air inlet and outlet of the air supply channel and adjusting the output power of the temperature control device according to the detected first temperature and second temperature, it is beneficial to improve the detection accuracy of the battery pack temperature, and further to improve the control accuracy of the battery pack temperature.

[0063] In some embodiments, the temperature control method of the energy storage system of this embodiment can cool the energy storage system, and the fan blows the cold air of the air conditioner to the temperature control device.

[0064] In some embodiments of the present application, step S300 includes:

[0065] S310: Setting the temperature control device to different output powers, and obtaining the first temperature and the second temperature under different output power conditions; specifically, corresponding values ​​of the output power, the first temperature and the second temperature can be obtained.

[0066] S320: Obtain a first correspondence table of the first temperature, the second temperature and the output power according to different output powers and their corresponding first and second temperatures, wherein the first correspondence table is used to provide a required output power value in adjusting the output power of the temperature control device.

[0067] That is to say, the energy storage system can be tested in advance to obtain the above-mentioned first corresponding relationship table, so as to conveniently adjust the output power of the temperature control device later.

[0068] In some embodiments of the present application, step S300 includes: when the number of times the output power of the temperature control device is adjusted is greater than a first preset number, increasing the air supply speed of the air supply device.

[0069] It is understandable that the first preset number of times can be 3 times. When the first temperature and the second temperature still cannot reach the preset value after adjustment 3 times, it is necessary to adjust the air supply speed of the air supply device, which is conducive to adjusting the first temperature and the second temperature to the preset value more quickly.

[0070] In some embodiments, when the number of times the output power of the temperature control device is adjusted is less than or equal to the first preset number of times, there is no need to adjust the air supply device.

[0071] In some embodiments of the present application, step S300 includes:

[0072] When the number of times the output power of the temperature control device is adjusted is equal to the second preset number of times, the air supply speed of the air supply device is adjusted to the maximum wind speed; the second preset number of times is greater than the first preset number of times;

[0073] It is understandable that the second preset number of times can be 5 times, the 4th adjustment can increase the air supply speed of the fan, but not to the maximum, and the 5th adjustment can adjust the air supply speed to the maximum. The control accuracy can be improved through step-by-step adjustment.

[0074] When the number of times the temperature control device output power is adjusted exceeds the second preset number, a shutdown alarm is issued. It is understandable that when the number of times the temperature control device output power is adjusted reaches the sixth time, it means an abnormality occurs, and a shutdown alarm is required at this time to prevent damage to the energy storage system.

[0075] In some embodiments of this application, please continue to refer to Figure 2 , after step S400, including:

[0076] S500: Obtain the third temperature of each battery cell, and determine whether the third temperature is within a third preset temperature range; specifically, obtain the current temperature of each battery cell in real time through a temperature sensor installed on each battery cell, and the third preset temperature range is set based on the optimal working conditions, safety limits and material properties of the battery cell.

[0077] S600: If the third temperature is outside the third preset temperature range, adjust the air supply speed of the air supply device until the third temperature is within the third preset temperature range; specifically, in order to adjust the battery cell temperature back to a safe range, the system controls the air supply speed of the air supply device (such as a fan or a cooling system). This can be achieved by increasing or decreasing the air supply volume, depending on whether the battery cell is overheated or overcooled.

[0078] S700: When the third temperature is within the third preset temperature range, the air supply device is locked to the current first air supply speed. Specifically, when the third temperature of all battery cells is stably maintained within the preset third temperature range, the system considers that the current cooling / heating condition is appropriate.

[0079] It is understandable that the energy storage system using air cooling has higher operating stability and reliability, but the temperature consistency is poor. The temperature difference of the battery module is usually as high as 5°C, and the temperature difference of the battery cell can reach 8°C, which seriously affects the cycle life of the energy storage system. The fan speed of each battery pack in the air-cooled temperature control system in the related technology is the same, and the air-conditioning operation status is adjusted only according to the ambient temperature. Since the battery pack is at different distances from the air duct outlet, this method is likely to cause a large temperature difference between the battery pack and the battery cell, low temperature consistency, and the system must always operate under the conditions that meet the cooling capacity of the battery cell with the highest temperature, and the system power consumption is large. At present, the temperature control strategy is usually limited to a certain range of temperature points, which may easily lead to a large difference between the highest and lowest temperatures although the temperature is within the limit, so the temperature control is not accurate, which also leads to low temperature consistency of the battery cell.

[0080] However, in this application, a temperature control device can be used to perform primary temperature regulation on multiple battery packs, and then the corresponding battery packs can be temperature regulated at the secondary level through the air supply device of each battery pack. Specifically, temperature sensors are added at the air inlet and outlet of the battery pack to connect to the BMS system, and combined with a multi-level temperature control strategy, the air conditioning cooling power is adjusted through the primary temperature control to control the temperature of the battery pack, and then the temperature of the battery cell is adjusted through the secondary temperature control; this improvement realizes the precise control of the temperature from the battery pack to the battery cell, improves the cycle life and energy storage of the battery cell, and reduces the energy consumption of the temperature control system.

[0081] It should be noted that through the two-level temperature control strategy and the fan separation speed control method, the temperature difference between each battery pack can be controlled within 2°C, and the temperature difference between the cells in the same battery pack can be controlled within 5°C, thereby improving the consistency of the batteries in the air-cooled energy storage system, extending the system cycle life, and reducing the system power consumption to improve the system efficiency.

[0082] In some embodiments of the present application, step S600 includes:

[0083] S610: Setting the air supply device to different air supply speeds, and obtaining the third temperature under the different air supply speed conditions; specifically, corresponding values ​​of the air supply speed and the third temperature can be obtained.

[0084] S620: According to different air supply speeds and their corresponding third temperatures, a second correspondence table of the third temperature and the air supply speed is obtained, and the second correspondence table is used to provide the required air supply speed value in adjusting the air supply speed of the temperature control device. In other words, the energy storage system can be tested in advance to obtain the above-mentioned second correspondence table, so as to conveniently adjust the air supply speed of the air supply device later.

[0085] In some embodiments, the third temperature in the second correspondence table may be an average temperature of all battery cells in the battery pack.

[0086] In some embodiments of the present application, step S600 includes:

[0087] When the number of times the air supply speed of the air supply device is adjusted is greater than the third preset number, the temperature control device is adjusted to a different output power. For example, the third preset number may be 3 times. After 3 adjustments, if the third temperature still cannot be adjusted to within the preset range, the temperature control device is adjusted back to the previous step.

[0088] In some embodiments of this application, please continue to refer to Figure 2 , after step S700, including:

[0089] S800: Obtain a first sub-temperature of a battery cell with the highest temperature and a second sub-temperature of a battery cell with the lowest temperature among the multiple battery cells, and calculate a temperature difference between the first sub-temperature and the second sub-temperature;

[0090] S900: Determine whether the temperature difference is within the preset temperature difference range. If not, adjust the air supply speed of the air supply device until the temperature difference is within the preset temperature difference range. Specifically, if the temperature difference exceeds the preset range, the system will start the adjustment mechanism of the air supply device to change the cooling / heating effect of the battery cell by increasing or decreasing the air supply speed. This adjustment process can be iterative, that is, the system will adjust the wind speed according to the current temperature difference, and then check the temperature difference again until it returns to the preset range.

[0091] S1000: When the temperature difference is within a preset temperature difference range, the air supply device is locked to a current second air supply speed. Specifically, the second air supply speed can further reduce the temperature difference of the battery pack compared to the first air supply speed.

[0092] It can be understood that by detecting the first sub-temperature and the second sub-temperature, the temperature difference in the battery pack can be further reduced to increase the life of the battery pack.

[0093] In some embodiments of the present application, step S900 includes:

[0094] Setting the air supply device to different air supply speeds, and obtaining the first sub-temperature and the second sub-temperature under the different air supply speed conditions;

[0095] According to different air supply speeds and their corresponding first sub-temperatures and second sub-temperatures, a third correspondence table of the first sub-temperature, the second sub-temperature and the air supply speed is obtained. The third correspondence table is used to provide the required air supply speed value in adjusting the air supply speed of the temperature control device.

[0096] Specifically, the third correspondence table may include the average temperature of the battery cells, the temperature difference, and the fan speed.

[0097] In some embodiments of the present application, step S900 includes:

[0098] If the number of times the air supply speed of the air supply device is adjusted is greater than the fourth preset number, the adjustment returns to the first air supply speed of the air supply device. For example, the fourth preset number may be 3 times. After 3 adjustments, if the second air supply speed still cannot be adjusted to a suitable speed, the adjustment returns to the first air supply speed and is repeated.

[0099] Example 1: Please continue to see Figure 1 Also see Figure 3 , Figure 3 A flow chart of the temperature control method of the energy storage system provided in this embodiment is shown. In this embodiment, T is the temperature of the air inlet and outlet of the battery pack, i represents input, i.e., the air inlet, o represents output, i.e., the air outlet, and n is the serial number of the battery pack. For example, Ti1 is the air inlet temperature of battery pack 1; t represents the temperature of the single cell, n is the serial number of the battery pack as above, and m is the serial number of the cell in the battery pack. For example, t11 is the temperature of the cell with serial number 1 in battery pack 1; min represents the minimum temperature set by the system, and max represents the maximum temperature set by the system. Depending on the model and number of cells in the battery pack, the set temperature limit will be different. For a 280Ah lithium iron phosphate cell with a rated charge and discharge power of 0.5C and a configuration of 24PCS in series in a battery pack, usually Timin can be set to 18°C, Timax can be set to 25°C, Tomin can be set to 20°C, and Tomax can be set to 30°C.

[0100] Each BMU collects the corresponding battery pack inlet and outlet temperatures through the temperature sensors at the inlet and outlet every 60 to 120 seconds, and transmits the data to the BCU for processing in real time, making a first-level adjustment judgment, that is, when the inlet temperature is within the set inlet temperature threshold and the outlet temperature is within the set outlet temperature threshold, the air conditioning cooling power is locked unchanged. If it is not within the threshold range, the BCU issues a command to adjust the air conditioning cooling power according to the table lookup method (the table is a matrix comparison table of inlet / outlet temperature and air conditioning power, with inlet temperature in the horizontal column and outlet temperature in the vertical column). At this time, the calculation of the number of cycle adjustments k1 begins. If k1≤3, that is, the temperature range is met within 3 cycle adjustments, the air conditioning cooling power is locked unchanged; if it cannot be met, k1=4, that is, the temperature range is still not met after the third adjustment, the fan speed is adjusted to 75% and the air conditioning cooling power is adjusted again (the initial fan speed is set to 25%). If the temperature range is met, the air conditioning cooling power is locked unchanged; if it cannot be met, k1=5, that is, the temperature range is still not met after the fourth adjustment, the fan speed is adjusted to 100% and the air conditioning cooling power is adjusted again. If the temperature range is met, the air conditioning cooling power is locked unchanged; if it cannot be met, k1=6, that is, the fan runs at full speed, and the temperature cannot be effectively controlled when the air conditioning cooling power is at its maximum, then the system stops and alarms.

[0101] After the inlet and outlet temperatures of the battery pack meet the temperature range and the air conditioning cooling power is locked, the secondary adjustment judgment is performed. The BMU compares the collected temperatures of each single cell with the set single cell temperature threshold. If all cell temperatures are within the threshold, the fan speed of the corresponding battery pack is locked unchanged. If it is not within the threshold range, the BMU issues a command to adjust the corresponding fan speed according to the average temperature tavgn of the battery cells in the battery pack through the algorithm of the relationship between the average temperature and the fan speed. At this time, the calculation of the number of adjustments k2 begins. If k2≤3, that is, the temperature range is met within 3 cycles, the fan speed v1 is temporarily locked. If it cannot be met, k1>4, that is, the temperature range is still not met after the third adjustment, then the system returns to the first-level adjustment and the BCU adjusts the air conditioning cooling power again. The temperature range of the single cell is set according to the cell model, manufacturer, working conditions and other conditions. For a 280Ah lithium iron phosphate cell with a rated charge and discharge power of 0.5C, tmin can usually be set to 20~28℃, tmax can be set to 28~35℃, and the maximum temperature difference can be set within the range of 4~6℃.

[0102] When the temperature of the single cell meets the temperature range, calculate △t, that is, the maximum single cell temperature - the minimum single cell temperature in the same battery pack. If △t≤3℃, the fan speed V2 (V2=V1) is locked. If △t>3℃, the BMU issues an instruction to further accurately control the fan speed according to the table lookup method (the table is a matrix comparison table formed by the average cell temperature tavgn and △t and the fan speed, with the horizontal column being the average cell temperature and the vertical column being the maximum temperature difference). At this time, the calculation of the number of adjustments k3 begins. If k3≤2, that is, the temperature difference meets the condition within 2 cycles, the fan speed V2 is locked unchanged; if it cannot be met, k3>3, that is, the temperature range cannot be met after the second adjustment, then no further accurate control will be made, and the fan will return to run at the speed V1 that meets the safety conditions.

[0103] Furthermore, in order to better implement the control method of the energy storage system in any of the above embodiments, based on the above control method of the energy storage system, the present application also provides an energy storage system, the energy storage system includes a temperature control device, a battery pack and an air supply device, the battery pack includes a plurality of battery cells arranged at intervals, and the temperature control method of the energy storage system is used to control the temperature control device and the air supply device to control the temperature of the battery pack.

[0104] In some embodiments, there may be multiple battery packs, and multiple battery packs share one temperature control device.

[0105] In some embodiments, the battery pack further includes a battery management unit (BMU), and the energy storage system includes a battery control unit (BCU). The battery management unit is used to obtain the first temperature, the second temperature, the third temperature, the first sub-temperature, and the second sub-temperature, and upload them to the battery control unit, which controls the fan and the air conditioner.

[0106] It needs to be explained that BMU is an important component of the battery management system (BMS), which is mainly responsible for monitoring and managing the status of each battery cell in the battery pack. It collects data through a variety of sensors (such as temperature sensors, voltage sensors, current sensors, etc.), and processes and analyzes these data to ensure the safe, efficient and reliable operation of the battery system. BCU is the main control module in the battery management system (BMS), responsible for the centralized control and management of the entire energy storage system. It receives data from each BMU, conducts comprehensive analysis and processing of these data to evaluate the overall status of the energy storage system, and sends control instructions to each BMU and other systems (such as air conditioning units) as needed.

[0107] In some embodiments, the cold air generated by the air conditioner flows in from the air inlet at the rear end of the battery PACK through the air duct, flows through the battery cell and then flows out from the adjustable speed fan at the front air outlet. An NTC temperature sensor (thermistor) is installed at the air inlet and outlet respectively to collect the temperature of the inlet / outlet, and the temperature signal is transmitted to the slave control module BMU of the BMS (battery management system) through a wire. Each BMU is connected to the main control module BCU (battery control unit) of the BMS in the control box through the CAN bus to realize signal transmission and control command issuance with the PACK; the BCU is connected to the air conditioning unit through the CAN bus or RS485 to realize signal transmission and control command issuance with the air conditioner; the BMU is connected to each battery cell pole ear through a wire to collect the temperature data of each battery cell monomer.

[0108] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0109] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0110] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0111] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0112] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A temperature control method for an energy storage system, It is characterized in that The energy storage system includes a temperature control device, a battery pack and an air supply device. The battery pack includes a plurality of cells arranged at intervals. The temperature control device is used to control the temperature of the battery pack. The air supply device is used to supply air to the air supply channels between the plurality of cells. The temperature control method includes: Starting the temperature control device and the air supply device, and obtaining a first temperature of an air inlet of the air supply channel and a second temperature of an air outlet of the air supply channel; Determining whether the first temperature is within a first preset temperature range, and whether the second temperature is within a second preset temperature range; If the first temperature is not within a first preset temperature range, and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range, and the second temperature is within the second preset temperature range; When the first temperature is within a first preset temperature range and the second temperature is within a second preset temperature range, the temperature control device is locked to a current output power.

2. The temperature control method of the energy storage system according to claim 1, It is characterized in that If the first temperature is not within a first preset temperature range, and the second temperature is not within a second preset temperature range, the method of adjusting the output power of the temperature control device includes: Setting the temperature control device to different output powers, and obtaining the first temperature and the second temperature under the different output power conditions; According to the different output powers and their corresponding first temperatures and second temperatures, a first correspondence table of the first temperature, the second temperature and the output power is obtained, and the first correspondence table is used to provide the required output power value in adjusting the output power of the temperature control device.

3. The temperature control method of the energy storage system according to claim 1 or 2, It is characterized in that If the first temperature is not within a first preset temperature range and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range and the second temperature is within the second preset temperature range comprises: When the number of times the output power of the temperature control device is adjusted is greater than the first preset number, the air supply speed of the air supply device is increased.

4. The temperature control method of the energy storage system according to claim 3, It is characterized in that If the first temperature is not within a first preset temperature range and the second temperature is not within a second preset temperature range, adjusting the output power of the temperature control device until the first temperature is within the first preset temperature range and the second temperature is within the second preset temperature range comprises: When the number of times the output power of the temperature control device is adjusted is equal to a second preset number of times, adjusting the air supply speed of the air supply device to a maximum wind speed; the second preset number of times is greater than the first preset number of times; When the number of times the output power of the temperature control device is adjusted is greater than a second preset number, a shutdown alarm is issued.

5. The temperature control method of the energy storage system according to claim 1, It is characterized in that The method of locking the temperature control device to the current output power when the first temperature is within the first preset temperature range and the second temperature is within the second preset temperature range comprises: Acquiring a third temperature of each of the battery cells, and determining whether the third temperature is within a third preset temperature range; If the third temperature is outside the third preset temperature range, adjusting the air supply speed of the air supply device until the third temperature is within the third preset temperature range; When the third temperature is within the third preset temperature range, the air supply device is locked to the current first air supply speed.

6. The temperature control method of the energy storage system according to claim 5, It is characterized in that If the third temperature is outside the third preset temperature range, adjusting the air supply speed of the air supply device until the third temperature is within the third preset temperature range comprises: Setting the air supply device to different air supply speeds, and obtaining the third temperature under the different air supply speed conditions; According to the different air supply speeds and their corresponding third temperatures, a second correspondence table between the third temperature and the air supply speed is obtained, and the second correspondence table is used to provide the required air supply speed value in adjusting the air supply speed of the temperature control device.

7. The temperature control method of the energy storage system according to claim 5, It is characterized in that If the third temperature is outside the third preset temperature range, adjusting the air supply speed of the air supply device until the third temperature is within the third preset temperature range comprises: When the number of times the air supply speed of the air supply device is adjusted is greater than a third preset number, the temperature control device is adjusted to a different output power.

8. The temperature control method of the energy storage system according to claim 7, It is characterized in that After locking the air supply device to the current first air supply speed, the method includes: Acquire a first sub-temperature of a battery cell with the highest temperature and a second sub-temperature of a battery cell with the lowest temperature among the plurality of battery cells, and calculate a temperature difference between the first sub-temperature and the second sub-temperature; Determine whether the temperature difference is within a preset temperature difference range, and if not, adjust the air supply speed of the air supply device until the temperature difference is within the preset temperature difference range; When the temperature difference is within the range of the preset temperature difference, the air supply device is locked to the current second air supply speed.

9. The temperature control method of the energy storage system according to claim 8, It is characterized in that Before the air supply speed of the air supply device is adjusted until the temperature difference is within the range of the preset temperature difference, the method includes: Setting the air supply device to different air supply speeds, and obtaining the first sub-temperature and the second sub-temperature under the different air supply speed conditions; According to the different air supply speeds and their corresponding first sub-temperatures and second sub-temperatures, a third correspondence table of the first sub-temperatures, the second sub-temperatures and the air supply speeds is obtained, and the third correspondence table is used to provide the required air supply speed value in adjusting the air supply speed of the temperature control device.

10. An energy storage system, It is characterized in that The energy storage system includes a temperature control device, a battery pack and an air supply device. The battery pack includes a plurality of battery cells arranged at intervals. The temperature control method of the energy storage system described in any one of claims 1 to 9 is used to control the temperature control device and the air supply device to control the temperature of the battery pack.

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