Thermal management control method of energy storage system

Abstract

The invention provides a thermal management control method for an energy storage system. The thermal management control method comprises the following steps: acquiring information of a battery system; acquiring information of the liquid cooling system; judging whether the communication between the battery system and a control system is normal or not, and if yes, adopting a first control mode: controlling the operation of the liquid cooling system based on the information of the battery system and the information of the liquid cooling system at the same time; if not, a second control mode is adopted, and operation of the liquid cooling system is controlled only through the information of the liquid cooling system. The operation of the liquid cooling system is controlled based on the operation information of the battery system and the operation information of the liquid cooling system at the same time, the regulation and control efficiency is higher, the operation duration of the liquid cooling system can be shortened, and the operation life of the system is greatly prolonged.

Description

Technical Field

[0001] The present invention relates to the field of energy storage, and in particular to a thermal management control method for an energy storage system capable of optimizing energy consumption. Background Art

[0002] Thermal management is a very important technology for energy storage systems. Heat dissipation performance is not only related to the performance of the energy storage system, but also to the safety of the energy storage system. Liquid cooling has become a common heat dissipation method. At present, for energy storage systems based on liquid cooling thermal management, most of the thermal management algorithms are turned on and off based on the inlet and outlet water temperatures. The working mode is: when the temperature of the coolant reaches the threshold of heating and cooling, the corresponding operating mode is turned on. This method will increase the auxiliary power consumption of the liquid cooling unit, increase the running time of the water machine, and thus reduce the life of the water machine.

[0003] The inventors have found that the current liquid cooling unit control method only considers the temperature of the coolant, but does not consider the temperature of the batteries in the energy storage system or the operating status of the energy storage system. It is not objective enough to adjust the heating and cooling power, which is one of the key factors in energy consumption.

[0004] In view of this, it is necessary to provide an improved thermal management control method for an energy storage system to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art and provide a thermal management control method for an energy storage system.

[0006] In order to achieve one of the above-mentioned invention objects, the present invention adopts the following technical solution:

[0007] A thermal management control method for an energy storage system comprises the following steps:

[0008] Get information about the battery system;

[0009] Get information about the liquid cooling system;

[0010] Determine whether the battery system and the control system are communicating normally. If so, adopt the first control mode: control the operation of the liquid cooling system based on both the information of the battery system and the information of the liquid cooling system; if not, adopt the second control mode: control the operation of the liquid cooling system only based on the information of the liquid cooling system.

[0011] Furthermore, the information of the battery system includes the battery cell temperature, the battery charge and discharge status, and the ratio of the current capacity to the rated capacity of the battery; wherein the battery cell temperature includes the battery cell minimum temperature, the battery cell average temperature, and the battery cell maximum temperature;

[0012] The information of the liquid cooling system includes the operating status of the refrigeration unit, the operating status of the heater, the operating status of the circulation pump, and the temperature of the coolant; wherein the temperature of the coolant includes the outlet temperature T of the liquid flowing from the liquid cooling system to the battery system. 出 , the return liquid temperature T from the battery system to the liquid cooling system 回 .

[0013] Furthermore, if the acquired information of the battery system is abnormal, or the information of the battery system cannot be acquired after multiple acquisitions, or the information of the battery system cannot be acquired within a predetermined time, then the communication between the battery system and the control system is abnormal.

[0014] Furthermore, in the first control mode, the energy storage system thermal management control method comprises the following steps:

[0015] Obtain the battery cell temperature and compare the battery cell temperature with the corresponding battery cell temperature threshold;

[0016] Get the coolant temperature and compare the coolant temperature with the current battery cell temperature;

[0017] When the cell temperature ≥ the corresponding cell temperature threshold, determine whether the coolant temperature is 5°C lower than the cell temperature. If so, run the self-circulation mode: start the circulation pump; if not, run the refrigeration mode: start the refrigeration unit and the circulation pump at the same time; when the cell temperature is < the corresponding cell temperature threshold, determine whether the coolant temperature is 5°C higher than the cell temperature. If so, run the self-circulation mode: start the circulation pump; if not, run the refrigeration mode: start the heater and the circulation pump at the same time.

[0018] Furthermore, in the cooling mode, the energy storage system thermal management control method comprises the following steps:

[0019] Obtain charging and discharging information of the battery system;

[0020] Determine whether the battery system is charging or discharging. If so, control the operation of the liquid cooling system based on the battery cell temperature threshold in the charging and discharging state; if not, control the operation of the liquid cooling system based on the battery cell temperature threshold in the static state; wherein the battery cell temperature threshold in the charging and discharging state is different from the battery cell temperature threshold in the static state.

[0021] Furthermore, the lowest temperature threshold of the battery cell in the charging and discharging state is ≤ the lowest temperature threshold of the battery cell in the static state; the average temperature threshold of the battery cell in the charging and discharging state is ≤ the average temperature threshold of the battery cell in the static state; the highest temperature threshold of the battery cell in the charging and discharging state is ≥ the highest temperature threshold of the battery cell in the static state.

[0022] Furthermore, “controlling the operation of the liquid cooling system based on the battery cell temperature threshold value of the charge and discharge state” includes: when the average battery cell temperature ≥ T 制冷1Or the maximum cell temperature ≥T 制冷2 , turn on the refrigeration unit; when the average temperature of the battery cell is ≤T 制冷3 Or the lowest cell temperature ≤T 制冷4 , turn off the refrigeration unit; where T 制冷1 >Battery cell average temperature threshold>T 制冷3 , T 制冷2 ≤ Maximum cell temperature threshold, T 制冷4 >Minimum cell temperature threshold.

[0023] Furthermore, “controlling the operation of the liquid cooling system based on the battery cell temperature threshold in the static state” includes: when the average battery cell temperature ≥ T 制冷5 Or the maximum cell temperature ≥T 制冷6 , turn on the refrigeration unit, when the average temperature of the battery cell is ≤T 制冷7 Or the lowest cell temperature ≤T 制冷8 , turn off the refrigeration unit; where T 制冷6 >Cell maximum temperature threshold>T 制冷5 >Battery cell average temperature threshold>T 制冷7 >Battery cell minimum temperature threshold ≥T 制冷8 .

[0024] Furthermore, in the heating mode, when the average cell temperature is ≤T 加热1 Or the lowest cell temperature ≤T 加热2 , turn on the heater; when the average cell temperature ≥ T 加热3 Or the maximum cell temperature ≥T 加热4 , turn off the heater; where T 加热1 <T 加热3 <Battery cell average temperature threshold, T 加热2 <Battery cell minimum temperature threshold, T 加热4 <Maximum cell temperature threshold.

[0025] Furthermore, the self-circulation mode is operated, when the battery cell temperature difference is ≥△T1, the circulation pump is turned on; when the battery cell temperature difference is ≤△T2, the circulation pump is turned off; wherein, the battery cell temperature difference = battery cell maximum temperature - battery cell minimum temperature, △T1 ≥ battery cell maximum temperature threshold - battery cell minimum temperature threshold, △T2 ≤ battery cell maximum temperature threshold - battery cell minimum temperature threshold.

[0026] Furthermore, when the self-circulation mode is run to cool the battery cell, the refrigeration unit is started to cool the coolant at the same time, and the refrigeration power of the refrigeration unit is lower than the refrigeration power of the refrigeration mode;

[0027] Or, when running the self-circulation mode to cool the battery cells, delay starting the refrigeration unit to cool the coolant.

[0028] Furthermore, in the second control mode, the circulation pump is started and the cooling liquid outlet temperature T 出, return liquid temperature T 回 , or the temperature difference between the outlet liquid temperature and the return liquid temperature to start or shut down the refrigeration unit.

[0029] Furthermore, the energy storage system thermal management control method also includes: obtaining the ratio of the current power of the battery cell to the capacitance, and controlling the operating status of the refrigeration unit and the heater according to the ratio.

[0030] Furthermore, when the ratio is ≥0.9 or the ratio is ≤0.1, it is determined whether the refrigeration unit or heater is running. If so, it is kept running, or kept running after reducing the power; if not, the refrigeration unit or heater is not started, or the refrigeration unit or heater is started with a power less than the rated refrigeration power.

[0031] The beneficial effects of the present invention are as follows: the energy storage system thermal management control method of the present invention controls the operation of the liquid cooling system based on the operating information of the battery system and the operating information of the liquid cooling system at the same time, and the regulation efficiency is more efficient, and the operating time of the liquid cooling system can be reduced, thereby greatly improving the operating life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a topological diagram of the liquid-cooled energy storage system of the present invention;

[0033] Figure 2 A thermal management control method for an energy storage system according to a preferred embodiment of the present invention;

[0034] Figure 3 This is another preferred embodiment of a thermal management control method for an energy storage system of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0036] In the various drawings of the present invention, for the convenience of illustration, some sizes of structures or parts are exaggerated relative to other structures or parts, and thus, they are only used to illustrate the basic structure of the subject matter of the present invention.

[0037] Please refer to Figure 1 to Figure 3 As shown, the present invention provides a liquid-cooled energy storage system and a thermal management control method for the energy storage system, which aims to comprehensively consider the information of the battery system and the information of the liquid cooling system for thermal management, so as to optimize the control method of the liquid cooling system while maintaining the temperature of the battery system, reduce the energy consumption of the liquid cooling system, and extend its service life.

[0038] For details, please refer to Figure 1As shown, the liquid-cooled cold storage system includes a battery system, a liquid cooling system for providing cold or heat to the battery system, and a control system communicatively connected to both the battery system and the liquid cooling system.

[0039] The battery system includes a plurality of battery clusters, which are formed by connecting a plurality of battery packs in series. The battery pack includes a battery cell and a liquid cooling plate, which is connected to a liquid cooling system to cool or heat the battery cell.

[0040] A plurality of battery clusters are arranged in the vertical direction, and each of the battery clusters includes a plurality of battery packs arranged in an array. In a preferred embodiment, Figure 1 As shown, taking the battery system including 24 battery packs as an example, every 6 battery packs are arranged in 3 columns and 2 rows and connected in series to form a battery cluster, and 4 battery clusters are arranged vertically; that is, the 24 battery packs are arranged in 3 columns and 8 rows.

[0041] The battery system also includes a battery management system (BMS) for monitoring the operating status of the battery pack, which can specifically monitor various status indicators of the battery pack, including voltage, temperature, input / output current, power, etc. The BMS can communicate with the control system via CAN, USB or wireless communication protocol to send the operating status of the battery pack.

[0042] Furthermore, two battery systems can be arranged side by side, with a shared control system placed in the middle, which is arranged reasonably and compactly. Figure 1As shown, the control system in the figure obtains the temperature of the cells in 48 battery packs through Can communication, and divides the correspondence between the 48 packs and the 4 liquid cooling units into 4 groups of data: No. 1 liquid cooling unit corresponds to (pack 1-2, pack 1-3, pack 1-4, pack 2-2, pack 2-3, pack 2-4, pack 3-2, pack 3-3, pack 3-4, pack 4-2, pack 4-3, pack 4-4) a total of 12 packs. No. 2 liquid cooling unit corresponds to (pack 1-1, pack 1-5, pack 1-6, pack 2-1, pack 2-5, pack 2-6, pack 3-1, pack 3-5, pack 3-6, pack 4-1, pack 4-5, pack 4-6) a total of 12 packs. Liquid cooling unit No. 3 corresponds to (pack 5-1, pack 5-2, pack 5-6, pack 6-1, pack 6-2, pack 6-6, pack 7-1, pack 7-2, pack 7-6, pack 8-1, pack 8-2, pack 8-6) for a total of 12 packs; liquid cooling unit No. 4 corresponds to (pack 5-3, pack 5-4, pack 5-5, pack 6-3, pack 6-4, pack 6-5, pack 7-3, pack 7-4, pack 7-5, pack 8-3, pack 8-4, pack 8-5) for a total of 12 packs.

[0043] The liquid cooling system includes at least two liquid cooling units that provide cooling or heat to the battery system, and each battery cluster is provided with cooling or heat by at least two liquid cooling units. Taking two liquid cooling units as an example, a portion of the battery packs in each battery cluster are provided with cooling or heat by one liquid cooling unit, and another portion of the battery packs are provided with cooling or heat by another liquid cooling unit; therefore, the heat generation of each liquid cooling unit is small, and the flow rate and flow resistance of the coolant are small, and the temperature difference between the battery packs in the same battery cluster can be reduced, thereby increasing the service life of the battery packs. At the same time, it is easy to maintain and reduces maintenance costs.

[0044] The liquid cooling unit includes a coolant, a refrigeration unit that provides coldness to the coolant, a heater that provides heat to the coolant, a circulation pump that drives the coolant to circulate between the liquid cooling unit and the liquid cooling plate of the battery system, and a liquid cooling controller. When the refrigeration unit and the circulation pump are turned on, low-temperature coolant is provided to the battery system to cool the battery cells; when the heater and the circulation pump are turned on, high-temperature coolant is provided to the battery system to heat the battery cells; when only the circulation pump is turned on, the coolant circulates and performs heat exchange with the battery cells to provide coldness or heat to them.

[0045] Specifically, Figure 1 As shown, the battery packs in the first and third columns of each battery cluster are cooled or heated by two liquid cooling units respectively, and the battery packs in the second column are cooled or heated alternately by two liquid cooling units from top to bottom.

[0046] The control system includes an information acquisition module, an information processing module and an information output module. In some application scenarios, the hardware and software control of the BMS and / or the liquid cooling controller can be integrated into the control system. For example, the BMS mainly monitors the information of the battery system, and the information acquisition module, information processing module, and information output module of the control system and the liquid cooling controller are respectively combined into one to control the operation of the liquid cooling system.

[0047] The information acquisition module is connected to the BMS for obtaining the operating information of the battery system; and the information acquisition module is connected to the liquid cooling controller for obtaining the operating information of the liquid cooling system. The information processing module optimizes the operating mode of the liquid cooling system according to the information obtained by the information acquisition module, and feeds back to the liquid cooling system through the information output module or directly controls its operation.

[0048] Based on the above system, each liquid cooling unit manages part of the battery pack. This method has high reliability. Even if a liquid cooling unit is damaged, only the corresponding battery pack cannot operate, and the remaining battery packs can continue to operate. In addition, the distributed system does not need to occupy a large space, which is more conducive to the structural arrangement of the energy storage system.

[0049] For details, please refer to Figure 2-3 As shown, the energy storage system thermal management control method includes the following steps:

[0050] S1 obtains information about the battery system;

[0051] S2 obtains information of the liquid cooling system;

[0052] S3 determines whether the battery system and the control system communicate normally. If so, the first control mode is adopted: the operation of the liquid cooling system is controlled based on the information of the battery system and the information of the liquid cooling system at the same time; if not, the second control mode is adopted: the operation of the liquid cooling system is controlled only by the information of the liquid cooling system.

[0053] It should be noted that in the control method, the battery system information corresponds to the control of the liquid cooling system operation. What is controlled according to the battery system information (cell temperature, etc.) is the operating state of the liquid cooling unit that provides cold or heat to the corresponding battery pack.

[0054] Specifically, in step S1, the information of the battery system includes but is not limited to: battery cell temperature, battery charge and discharge status, ratio of current capacity to rated capacity, etc. The battery cell temperature includes minimum temperature, average temperature and maximum temperature.

[0055] In step S2, the information of the liquid cooling system includes but is not limited to: the operating status of the refrigeration unit, the operating status of the heater, the operating status of the circulation pump, and the temperature of the coolant. The temperature of the coolant includes the outlet temperature T of the liquid flowing from the liquid cooling system to the battery system. 出 , the return liquid temperature T from the battery system to the liquid cooling system 回 .

[0056] In step S3, if the information of the battery system obtained is abnormal, or the information of the battery system cannot be obtained after multiple attempts (for example, 2 to 5 times), or the information of the battery system cannot be obtained within a predetermined time (for example, 60 seconds), it is considered that the communication between the battery system and the control system is abnormal, and the first control mode should be used to control the operation of the liquid cooling system.

[0057] In the first control mode, "controlling the operation of the liquid cooling system based on the information of the battery system and the information of the liquid cooling system" means: obtaining the battery cell temperature in real time, and comparing the battery cell temperature with the corresponding battery cell temperature threshold. When the battery cell needs to be cooled, the liquid cooling system needs to be controlled to provide cooling to the battery system; when the battery cell needs to be heated, the liquid cooling system needs to provide heat to the battery system; at the same time, according to the temperature difference between the coolant and the battery cell, it is determined whether the refrigeration unit and the heater need to be turned on, thereby summarizing the operation modes of the liquid cooling system into the following three types: cooling mode, heating mode, and self-circulation mode. It specifically includes the following steps:

[0058] Obtain the battery cell temperature, and compare the battery cell temperature with the corresponding battery cell temperature threshold, for example, compare the battery cell minimum temperature with the battery cell minimum temperature threshold, compare the battery cell average temperature with the battery cell average temperature threshold, and compare the battery cell maximum temperature with the battery cell maximum temperature threshold;

[0059] Get the coolant temperature and compare the coolant temperature with the current battery cell temperature;

[0060] When the cell temperature is ≥ the corresponding cell temperature threshold, the cell needs to be cooled. Continue to determine whether the coolant temperature is 5°C lower than the cell temperature. If so, the coolant at the current temperature can provide cooling for the battery system, and the self-circulation mode is run: start the circulation pump; if not, the coolant at the current temperature is insufficient to provide cooling for the battery system, and the cooling mode is run: start the refrigeration unit and the circulation pump at the same time to provide cooling for the cell.

[0061] When operating in cooling mode, the energy storage system thermal management control method further includes the following steps:

[0062] Acquire charging and discharging information of the battery system, the charging and discharging information including but not limited to voltage and its changes, current and its changes, power and its changes, temperature and its changes, etc.;

[0063] Determine whether the battery system is charging or discharging. If so, control the operation of the liquid cooling system based on the battery cell temperature threshold in the charging and discharging state; if not, control the operation of the liquid cooling system based on the battery cell temperature threshold in the static state; wherein the battery cell temperature threshold in the charging and discharging state is different from the battery cell temperature threshold in the static state, as shown in Table 1 for specific reference.

[0064] Table 1

[0065] Charge and discharge status Static state illustrate Battery cell minimum temperature threshold T1 T1’ T1≤T1' Average cell temperature threshold T2 T2’ T2≤T2' Battery cell maximum temperature threshold T3 T3 T3≥T3'

[0066] The battery system will generate heat during the charge and discharge state, so T1≤T1', so as to start the liquid cooling system as soon as possible to avoid the over-high temperature of the battery cell due to untimely cooling; T3≥T3', so as to delay the closure of the liquid cooling system to avoid the phenomenon of over-high temperature of the battery cell after the liquid cooling system is shut down and no longer provides cooling. Of course, when the battery cell temperature is lower than T1, it is necessary to turn on the heater to provide heat to the battery system to ensure the normal operation of the battery pack.

[0067] Specifically, “controlling the operation of the liquid cooling system based on the battery cell temperature threshold of the charge and discharge state” includes: when the average battery cell temperature ≥ T 制冷1 Or the maximum cell temperature ≥T 制冷2 , turn on the refrigeration unit to start cooling; when the average temperature of the battery cell is ≤T 制冷3 Or the lowest cell temperature ≤T 制冷4 , turn off the refrigeration unit and stop refrigeration. Among them, T 制冷1 >Battery cell average temperature threshold>T 制冷3 , T 制冷2 ≤ Maximum cell temperature threshold, T 制冷4 >Minimum cell temperature threshold.

[0068] In a preferred embodiment, T 制冷1 At 25°C, T 制冷2 At 35°C, T 制冷3 At 22°C, T 制冷4 In cooling mode, the temperature of the coolant is 20°C, the temperature difference between the return liquid and the outlet liquid is 2°C, and the flow rate is 72L / min.

[0069] When the battery cell is in a stationary state, the battery cell will not generate a lot of heat. “Controlling the operation of the liquid cooling system based on the battery cell temperature threshold in the stationary state” includes: when the average battery cell temperature ≥ T 制冷5 Or the maximum cell temperature ≥T 制冷6 , turn on the refrigeration unit to start cooling; when the average temperature of the battery cell is ≤T制冷7 Or the lowest cell temperature ≤T 制冷8 , turn off the refrigeration unit and stop refrigeration. 制冷6 >Cell maximum temperature threshold>T 制冷5 >Battery cell average temperature threshold>T 制冷7 >Battery cell minimum temperature threshold>T 制冷8 , preferably T 制冷5 is the median temperature between the maximum cell temperature threshold and the average cell temperature threshold, T 制冷7 is the median temperature of the minimum cell temperature threshold and the average cell temperature threshold; T 制冷6 > The maximum temperature threshold of the battery cell is preferably 1°C to 2°C higher than the maximum temperature threshold of the battery cell; T 制冷8 ≤ the minimum temperature threshold of the battery cell, preferably 1°C to 2°C lower than the minimum temperature threshold of the battery cell.

[0070] In a preferred embodiment, T 制冷5 At 30°C, T 制冷6 At 35°C, T 制冷7 At 22°C, T 制冷8 In static mode, the temperature of the coolant is 20°C, the temperature difference between the return liquid and the outlet liquid is 2°C, and the flow rate is 72L / min.

[0071] When the cell temperature is less than the corresponding cell temperature threshold, the cell needs to be heated up to determine whether the coolant temperature is more than 5°C higher than the cell temperature. If so, the coolant at the current temperature can provide heat to the battery system, and the self-circulation mode is run: start the circulation pump; if not, the coolant at the current temperature is not enough to provide heat to the battery system, and the cooling mode is run: start the heater and circulation pump at the same time to provide heat to the cell.

[0072] Specifically, in the heating mode, when the average cell temperature ≤T 加热1 Or the lowest cell temperature ≤T 加热2 , turn on the heater to start heating; when the average cell temperature ≥ T 加热3 Or the maximum cell temperature ≥T 加热4 , turn off the heater to stop heating. Among them, T 加热1 <T 加热3 <Battery cell average temperature threshold, T 加热2 <Battery cell minimum temperature threshold, T 加热4 <Maximum cell temperature threshold.

[0073] In a preferred embodiment, T 加热1 18℃, T 加热2 At 15°C, T 加热3 At 22°C, T 加热4 is 35℃.

[0074] In the self-circulation mode: the coolant at the current temperature is sufficient to provide the required heat or cold to the battery system. Therefore, when the refrigeration unit and the heater are turned off, only the circulation pump is turned on to provide the battery system with cold or heat with the coolant at the current temperature.

[0075] Specifically, when the battery cell temperature difference ≥ △T1, the circulation pump is turned on; when the battery cell temperature difference ≤ △T2, the circulation pump is turned off. The battery cell temperature difference = the maximum temperature of the battery cell - the minimum temperature of the battery cell. △T1 ≥ the maximum temperature threshold of the battery cell - the minimum temperature threshold of the battery cell, indicating that the maximum temperature of the battery cell exceeds the maximum temperature threshold of the battery cell, and cooling is required, or the minimum temperature of the battery cell exceeds the minimum temperature threshold of the battery cell, and heat is required; △T2 ≤ the maximum temperature threshold of the battery cell - the minimum temperature threshold of the battery cell, indicating that the battery cell temperature is between the maximum temperature threshold and the minimum temperature threshold, and no cooling or heat is required.

[0076] In a preferred embodiment, ΔT1 is 8° C., and ΔT2 is 5° C. In the self-circulation mode, the temperature of the coolant is room temperature, and the flow rate is 72 L / min.

[0077] Furthermore, considering that the charging and discharging process of the battery cell can release a large amount of heat; therefore, even if the self-circulation mode can cool the battery cell, in order to avoid the subsequent rapid increase in the battery cell temperature, the refrigeration unit can also be started at the same time to cool the coolant. At this time, the refrigeration power of the refrigeration unit is lower than the refrigeration power of the refrigeration mode. For example, the refrigeration unit is operated at 30% to 70% of the rated refrigeration power to maintain the battery cell temperature within its operating temperature range throughout the process.

[0078] Or, when running the self-circulation mode to cool the battery cell, the refrigeration unit is started with a delay to cool the coolant. At this time, the refrigeration power of the refrigeration unit is not limited, and it can be cooled at rated power or reduced to a certain level.

[0079] As mentioned above, the self-circulation mode, heating mode and cooling mode can all keep the battery cells within a suitable temperature range.

[0080] In the second control mode, the circulation pump is started and the operation state of the liquid cooling system is controlled according to the temperature of the coolant. 出 , return liquid temperature T 回 , or the temperature difference between the outlet liquid temperature and the return liquid temperature, start or shut down the refrigeration unit.

[0081] Specifically, when the outlet temperature T 出 Higher than the outlet temperature threshold, return liquid temperature T 回 If the temperature is higher than the return liquid temperature threshold, or the temperature difference between the outlet liquid temperature and the return liquid temperature is higher than the temperature difference threshold, the refrigeration unit is started.

[0082] Furthermore, the thermal management control method of the energy storage system also includes: determining whether the battery cell temperature meets the standard, if so, ending the temperature control and stopping the operation of the liquid cooling system; if not, entering a new round of control method, that is, returning to the steps of obtaining battery system information and obtaining liquid cooling system information.

[0083] In addition, the thermal management control method of the energy storage system also includes: obtaining the ratio of the current power of the battery cell to the capacitance, judging the charging and discharging progress according to the ratio, and controlling the operating status of the refrigeration unit and the heater.

[0084] Specifically, when the ratio is ≥0.9 or the ratio is ≤0.1, it indicates that charging and discharging is about to end, and a large amount of heat will no longer be released. Therefore, it is further determined whether the refrigeration unit or heater is running. If so, keep running, or reduce the power (such as reducing it to 50% or less than the rated refrigeration power) and keep running; if not, do not start the refrigeration unit or heater, or start the refrigeration unit or heater with a power less than the rated refrigeration power (≤50% of the rated refrigeration power); this will not cause waste of cooling and heat, and has low energy consumption. It can also avoid frequent starting of the refrigeration unit and heater, thereby extending their service life.

[0085] In summary, the energy storage system thermal management control method of the present invention controls the operation of the liquid cooling system based on the operating information of the battery system and the operating information of the liquid cooling system, has a more efficient regulation efficiency, can reduce the operating time of the liquid cooling system, and greatly improves the system operating life.

[0086] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0087] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A thermal management control method for an energy storage system, characterized in that: The steps include: Get information about the battery system; Get information about the liquid cooling system; Determine whether the battery system and the control system are communicating normally. If so, adopt the first control mode: control the operation of the liquid cooling system based on both the information of the battery system and the information of the liquid cooling system; if not, adopt the second control mode: control the operation of the liquid cooling system only based on the information of the liquid cooling system.

2. The energy storage system thermal management control method according to claim 1, characterized in that: The information of the battery system includes the battery cell temperature, battery charge and discharge status, and the ratio of the current capacity to the rated capacity of the battery; wherein the battery cell temperature includes the battery cell minimum temperature, the battery cell average temperature, and the battery cell maximum temperature; The information of the liquid cooling system includes the operating status of the refrigeration unit, the operating status of the heater, the operating status of the circulation pump, and the temperature of the coolant; wherein the temperature of the coolant includes the outlet temperature T of the liquid flowing from the liquid cooling system to the battery system. 出 , the return liquid temperature T from the battery system to the liquid cooling system 回 .

3. The energy storage system thermal management control method according to claim 2, characterized in that: If the acquired information of the battery system is abnormal, or the battery system information cannot be acquired after multiple acquisitions, or the battery system information cannot be acquired within a predetermined time, then the communication between the battery system and the control system is abnormal.

4. The energy storage system thermal management control method according to claim 2, characterized in that: In the first control mode, the energy storage system thermal management control method comprises the following steps: Obtain the battery cell temperature and compare the battery cell temperature with the corresponding battery cell temperature threshold; Get the coolant temperature and compare the coolant temperature with the current battery cell temperature; When the cell temperature ≥ the corresponding cell temperature threshold, determine whether the coolant temperature is 5°C lower than the cell temperature. If so, run the self-circulation mode: start the circulation pump; if not, run the refrigeration mode: start the refrigeration unit and the circulation pump at the same time; when the cell temperature is < the corresponding cell temperature threshold, determine whether the coolant temperature is 5°C higher than the cell temperature. If so, run the self-circulation mode: start the circulation pump; if not, run the refrigeration mode: start the heater and the circulation pump at the same time.

5. The energy storage system thermal management control method according to claim 4, characterized in that: In the cooling mode, the energy storage system thermal management control method comprises the following steps: Obtain charging and discharging information of the battery system; Determine whether the battery system is charging or discharging. If so, control the operation of the liquid cooling system based on the battery cell temperature threshold in the charging and discharging state; if not, control the operation of the liquid cooling system based on the battery cell temperature threshold in the static state; wherein the battery cell temperature threshold in the charging and discharging state is different from the battery cell temperature threshold in the static state.

6. The energy storage system thermal management control method according to claim 5, characterized in that: The lowest temperature threshold of the battery cell in the charging and discharging state is ≤ the lowest temperature threshold of the battery cell in the static state; the average temperature threshold of the battery cell in the charging and discharging state is ≤ the average temperature threshold of the battery cell in the static state; the highest temperature threshold of the battery cell in the charging and discharging state is ≥ the highest temperature threshold of the battery cell in the static state.

7. The energy storage system thermal management control method according to claim 5, characterized in that: "Controlling the operation of the liquid cooling system based on the battery cell temperature threshold of the charge and discharge state" includes: when the average battery cell temperature ≥ T 制冷1 Or the maximum cell temperature ≥T 制冷2 , turn on the refrigeration unit; when the average temperature of the battery cell is ≤T 制冷3 Or the lowest cell temperature ≤T 制冷4 , turn off the refrigeration unit; where T 制冷1 >Battery cell average temperature threshold>T 制冷3 , T 制冷2 ≤ Maximum cell temperature threshold, T 制冷4 >Minimum cell temperature threshold.

8. The energy storage system thermal management control method according to claim 5, characterized in that: "Controlling the operation of the liquid cooling system based on the cell temperature threshold at rest" includes: when the average cell temperature ≥ T 制冷5 Or the maximum cell temperature ≥T 制冷6 , turn on the refrigeration unit, when the average temperature of the battery cell is ≤T 制冷7 Or the lowest cell temperature ≤T 制冷8 , turn off the refrigeration unit; where T 制冷6 >Cell maximum temperature threshold>T 制冷5 >Battery cell average temperature threshold>T 制冷7 >Battery cell minimum temperature threshold ≥T 制冷8 .

9. The energy storage system thermal management control method according to claim 4, characterized in that: In heating mode, when the average cell temperature is ≤T 加热1 Or the lowest cell temperature ≤T 加热2 , turn on the heater; when the average cell temperature ≥ T 加热3 Or the maximum cell temperature ≥T 加热4 , turn off the heater; where T 加热1 <T 加热3 <Battery cell average temperature threshold, T 加热2 <Battery cell minimum temperature threshold, T 加热4 <Maximum cell temperature threshold.

10. The energy storage system thermal management control method according to claim 4, characterized in that: Run the self-circulation mode, when the battery cell temperature difference ≥ △T1, turn on the circulation pump; when the battery cell temperature difference ≤ △T2, turn off the circulation pump; wherein, the battery cell temperature difference = battery cell maximum temperature - battery cell minimum temperature, △T1 ≥ battery cell maximum temperature threshold - battery cell minimum temperature threshold, △T2 ≤ battery cell maximum temperature threshold - battery cell minimum temperature threshold.

11. The energy storage system thermal management control method according to claim 10, characterized in that: When the self-circulation mode is used to cool the battery cells, the refrigeration unit is started to cool the coolant at the same time. The refrigeration power of the refrigeration unit is lower than the refrigeration power of the refrigeration mode. Or, when running the self-circulation mode to cool the battery cells, delay starting the refrigeration unit to cool the coolant.

12. The energy storage system thermal management control method according to claim 1, characterized in that: In the second control mode, the circulation pump is started and the coolant outlet temperature T 出 , return liquid temperature T 回 , or the temperature difference between the outlet liquid temperature and the return liquid temperature to start or shut down the refrigeration unit.

13. The energy storage system thermal management control method according to claim 1, characterized in that: The energy storage system thermal management control method also includes: obtaining the ratio of the current power of the battery cell to the capacitance, and controlling the operating status of the refrigeration unit and the heater according to the ratio.

14. The energy storage system thermal management control method according to claim 13, characterized in that: When the ratio is ≥0.9 or ≤0.1, determine whether the refrigeration unit or heater is running. If so, keep running or keep running after reducing the power; if not, do not start the refrigeration unit or heater, or start the refrigeration unit or heater with a power less than the rated refrigeration power.

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