Temperature control system of energy storage battery

Abstract

The invention discloses an energy storage battery temperature control system which comprises an energy storage EMS, an energy storage BMS, an energy storage PCS and a direct cooling unit, the energy storage BMS is used for collecting the temperature of a battery cell in real time, the energy storage PCS is used for collecting electrical parameters of the energy storage battery system in real time, the energy storage BMS and the energy storage PCS transmit the collected temperature data and electrical parameters to the energy storage EMS, and the direct cooling unit is connected with the energy storage EMS. And the energy storage EMS obtains the active power of the energy storage battery system according to the received electrical parameters, different temperature control strategies in different active power intervals are stored in the energy storage EMS, and the energy storage EMS controls the direct cooling unit to enter corresponding temperature control measures according to the received cell temperature data and the corresponding temperature control strategies. The direct cooling unit is jointly controlled through the energy storage EMS, the energy storage BMS and the energy storage PCS, multi-level judgment is adopted, accurate control over the battery temperature can be achieved, and it is guaranteed that the battery cell temperature is always within the optimal temperature range.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage batteries, and in particular to a temperature control system for an energy storage battery. Background Art

[0002] Under the background of dual carbon goals, electrochemical energy storage systems are developing rapidly. Safety and reliability have become urgent issues to be addressed in the development process. Among them, how to effectively manage the heat generated during the operation of the energy storage system is particularly important.

[0003] At present, the thermal management system of the energy storage system focuses on how to control the temperature consistency between the cells inside the battery PACK in the energy storage battery cabinet. Among them, liquid cooling technology is widely used in controlling the temperature of the energy storage battery system. The control core of this technology lies in controlling the heat exchange between the chiller and the energy storage battery system. In liquid cooling technology, the entire battery energy storage system is usually controlled by the return water temperature of the compressor. A temperature detection point is set in the return water section, and a minimum cooling temperature and a maximum heating temperature are set. When the water temperature of the return water pipe section exceeds the minimum cooling temperature, the chiller starts the cooling mode to cool the energy storage system; when the water temperature of the return water pipe section is lower than the maximum heating temperature, the chiller starts the heating mode to heat the energy storage system.

[0004] The current control strategy for liquid cooling systems has the following shortcomings: 1. The control method is not accurate enough. The temperature of the return pipe section cannot accurately reflect the actual temperature of the energy storage system, resulting in an inaccurate management strategy and, in turn, an inaccurate control method. 2. The temperature control range is too large. Even when the battery cell is in the optimal operating temperature range, the system may still issue unnecessary cooling or heating instructions, which can easily cause the ineffective operation of the chiller and cause waste. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a temperature control system for an energy storage battery, a direct cooling and heating control system based on a refrigerant. This control system can achieve precise control of the battery temperature through the joint control of the direct cooling unit by the energy storage EMS, energy storage BMS, and energy storage PCS, ensuring that the battery temperature is always within the optimal temperature range.

[0006] The technical solution adopted by the present invention is as follows: A temperature control system for an energy storage battery comprises an energy storage EMS, an energy storage BMS, an energy storage PCS and a direct cooling unit. The energy storage BMS is used to collect the temperature of a battery cell in real time. The energy storage PCS is used to collect the electrical parameters of the energy storage battery system in real time. The energy storage BMS and the energy storage PCS transmit the collected temperature data and electrical parameters to the energy storage EMS. The energy storage EMS obtains the active power of the energy storage battery system according to the received electrical parameters. The energy storage EMS stores different temperature control strategies in different active power ranges. The energy storage EMS controls the direct cooling unit to enter corresponding temperature control measures according to the received battery cell temperature data and the corresponding temperature control strategies.

[0007] As a preferred embodiment of the present invention, the energy storage EMS takes corresponding control measures on the direct cooling unit according to the working status of the direct cooling unit; if it is in the start-up state, the energy storage EMS controls the direct cooling unit to enter corresponding temperature control measures according to the current evaporation or condensation temperature of the direct cooling unit and the corresponding temperature control strategy; if it is in the shutdown state, the energy storage EMS performs multi-level judgment based on the collected battery cell temperature data and the corresponding temperature control strategy, and controls the direct cooling unit to enter corresponding temperature control measures according to the judgment results.

[0008] As a preferred embodiment of the present invention, the energy storage EMS enters the first level of judgment according to the active power of the energy storage battery system. The first level is to judge the corresponding active power interval in which the active power of the energy storage battery system is located, and select the temperature control strategy under the corresponding interval. The energy storage EMS enters the second level of judgment according to the selected temperature control strategy and the collected battery cell temperature data.

[0009] As a preferred embodiment of the present invention, the temperature control strategy includes a battery cell operating temperature range, and the second level is to determine whether the temperature of each battery cell is within the operating temperature range under the corresponding active power; If yes, the energy storage EMS enters the third level of judgment; If not, the energy storage EMS controls the direct cooling unit to perform cooling or heating.

[0010] As a preferred embodiment of the present invention, the temperature control strategy also includes an allowable range of temperature difference between groups of different battery cells. The energy storage EMS identifies and obtains the highest temperature and the lowest temperature in all received battery cell temperature data, and calculates the maximum temperature difference between groups. The third level is to determine whether the maximum temperature difference between groups is within the allowable range of temperature difference between groups under the corresponding active power. If yes, the energy storage EMS enters the fourth level of judgment; If not, the energy storage EMS controls the direct cooling unit to perform cooling or heating.

[0011] As a preferred embodiment of the present invention, it also includes a temperature and humidity tester arranged in the energy storage cabinet, which is used to detect the ambient temperature and humidity in the energy storage cabinet in real time, and transmit the measured ambient temperature data to the energy storage EMS, and the energy storage EMS stores the allowable range of ambient temperature. The fourth level is to determine whether the received ambient temperature is within the allowable range of ambient temperature; If so, the energy storage EMS issues a shutdown command to the direct cooling unit; If not, the energy storage EMS controls the direct cooling unit to perform cooling or heating.

[0012] As a preferred embodiment of the present invention, the temperature control strategy also includes an evaporation and condensation temperature setting value of the direct cooling unit. When the direct cooling unit is turned on, the direct cooling unit sends its real-time evaporation temperature and condensation temperature data to the energy storage EMS. The energy storage EMS receives the evaporation temperature and condensation temperature data and compares them with the evaporation and condensation temperature setting values ​​under the corresponding active power, respectively, to determine whether the two continue to meet the evaporation / condensation requirements within a specified time; the evaporation / condensation requirements are: evaporation temperature ≤ evaporation and condensation temperature setting value or condensation temperature ≥ evaporation and condensation temperature setting value; If it can last for at least ten minutes while meeting the evaporation / condensation requirements, the energy storage EMS will issue a shutdown command to the direct cooling unit; If the evaporation / condensation requirements are not met or it cannot last for ten minutes under the condition that the evaporation / condensation requirements are met, the energy storage EMS begins to determine whether the working mode of the direct cooling unit is cooling or heating mode. If it is cooling mode, the energy storage EMS receives all battery cell temperature data, identifies and obtains the highest battery cell temperature, and compares it with the cooling point temperature under the corresponding active power: if the highest battery cell temperature ≥ the cooling point temperature, the energy storage EMS issues a cooling instruction to the direct cooling unit; if the highest battery cell temperature < the cooling point temperature, it enters the third level of judgment, and controls the direct cooling unit to take corresponding temperature control measures according to the judgment result; If it is in heating mode, the energy storage EMS receives all the battery cell temperature data, identifies and obtains the lowest battery cell temperature, and compares it with the heating point temperature under the corresponding active power: if the lowest battery cell temperature is ≤ the cooling point temperature, the energy storage EMS issues a heating command to the direct cooling unit; if the highest battery cell temperature is greater than the cooling point temperature, it enters the third level of judgment, and controls the direct cooling unit to take corresponding temperature control measures based on the judgment results.

[0013] As a preferred embodiment of the present invention, the two endpoint values ​​of the operating temperature range are respectively a cooling point and a heating point, and the heating point ≤ operating temperature ≤ cooling point; the energy storage EMS identifies and obtains the highest temperature and the lowest temperature in all received battery cell temperature data, and compares the highest battery cell temperature with the cooling point under the corresponding active power: If the highest cell temperature is ≥ the cooling point temperature, the energy storage EMS will issue a cooling command to the direct cooling unit; If the maximum cell temperature is less than the cooling point temperature, the energy storage EMS will compare the minimum cell temperature with the heating point under the corresponding active power; If the lowest cell temperature is ≤ the heating point temperature, the energy storage EMS will issue a heating command to the direct cooling unit; If the lowest cell temperature is greater than the hot spot temperature, the energy storage EMS enters the third level of judgment.

[0014] As a preferred embodiment of the present invention, the energy storage EMS stores a preset temperature threshold. If the maximum temperature difference between groups does not meet the allowable range of the temperature difference between groups under the corresponding active power or the current ambient temperature does not meet the allowable range of the ambient temperature, the energy storage EMS takes the average of all the received battery cell temperature data and compares it with the temperature threshold: If the average cell temperature is ≥ the temperature threshold, the energy storage EMS issues a cooling command to the direct cooling unit; If the average cell temperature is less than the temperature threshold, the energy storage EMS will issue a heating command to the direct cooling unit.

[0015] As a preferred embodiment of the present invention, when the ambient temperature received by the energy storage EMS does not meet the allowable ambient temperature range, the energy storage EMS compares the received ambient temperature with the maximum allowable ambient temperature and the minimum allowable ambient temperature: If the ambient temperature is ≥ the maximum allowable ambient temperature, that is, it is in a high temperature environment, the energy storage EMS will issue a cooling command to the direct cooling unit; if the ambient temperature is ≤ the minimum allowable ambient temperature, that is, it is in a low temperature environment, the energy storage EMS will issue a heating command to the direct cooling unit.

[0016] Compared with the prior art, the present invention has the following improvements and beneficial effects: 1. The battery temperature control system of the present invention is a direct cooling and heating control system based on refrigerant. Compared with the coolant used in the traditional liquid cooling system, the refrigerant has a lower cost. Since the performance of the coolant will decay and impurities will accumulate after a period of use, it needs to be replaced regularly and the replacement cycle is short. The chemical composition and physical properties of the refrigerant are relatively stable and will not decay significantly over time. Therefore, it can be recycled in a closed system without replacement or a long replacement cycle. Therefore, the present invention uses refrigerant to control the battery temperature, which is lower in cost than the traditional liquid cooling system.

[0017] 2. The control system of the present invention stores different temperature control strategies under different active power intervals, and the corresponding temperature control strategy can be adopted according to the actual active power of the energy storage battery. This setting can make the battery temperature control more accurate, so as to more effectively avoid the risk of thermal runaway of the battery. Since the working power of the battery cell is different when the energy storage battery is charged and discharged at different powers, its heating rate is also different. If the battery cell is controlled in the same temperature range, the battery cell will heat up rapidly at full power. If the refrigeration is started after exceeding the temperature control range, it is very likely that the battery will be thermally runaway due to untimely heating, which will cause battery damage or even explosion and fire and other serious safety accidents. However, this scheme is provided with different temperature control strategies according to different active powers, so as to ensure that when charging and discharging at high power, a control strategy with a smaller temperature control range is adopted to control the battery in advance and dissipate heat in time, which can effectively reduce the risk of thermal runaway of the battery. When charging and discharging at low power, a control strategy with a larger temperature control range is adopted, which can ensure that refrigeration is started only after reaching the temperature control range, which can reduce the ineffective work of the direct cooling unit and save energy consumption. Therefore, by adopting different temperature control strategies, the battery temperature control can be made more precise, which can effectively ensure that the battery cell temperature is always within the optimal temperature range, which is beneficial to extending the service life of the battery cell. At the same time, it can effectively avoid thermal runaway, resulting in battery damage or even explosion and fire and other serious safety accidents. At the same time, it can also reduce the ineffective work of the direct cooling unit and save energy.

[0018] 3. Compared with the traditional liquid cooling technology control strategy, the battery temperature control system of the present invention adopts multi-level judgment. By judging the temperature of a single battery cell according to the temperature control strategy under different active powers, each battery cell can be monitored in real time to ensure that the temperature of each battery cell is always within the optimal temperature range. By real-time monitoring the component temperature between different battery cells, the temperature between the battery cells can be ensured to be consistent, ensuring that all battery cells in the battery pack can evenly perform at their best, making the output of the entire battery pack more stable, and at the same time, it can avoid uneven aging of the battery cells in the entire battery pack due to excessive temperature differences, affecting the overall life of the battery; in addition, the present invention also takes into account the impact of the external environment on the battery cells. By judging the ambient temperature and taking corresponding control measures, the battery cells can be kept within the optimal working range even in extreme environments of high or low temperatures.

[0019] 4. The battery temperature control system of the present invention realizes precise control over the operation of the direct cooling unit, ensuring that the direct cooling unit stops running when the battery cell is within the optimal temperature range, which not only avoids the ineffective work of the direct cooling unit, but also reduces the operating noise of the direct cooling unit. Once the battery cell temperature exceeds or falls below the optimal temperature range, the system can quickly and accurately control the direct cooling unit to enter the cooling or heating mode, thereby improving the working efficiency of the direct cooling unit. The present invention not only optimizes energy efficiency, but also reduces environmental noise. Compared with the traditional liquid cooling technology control strategy, it has significant improvements in practicality and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flowchart of the temperature control process of the energy storage battery in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0022] In the description of the present application, the terms "top", "bottom", "one end", "one side", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the structure referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0023] The present embodiment discloses a temperature control system for an energy storage battery, including an energy storage EMS, an energy storage BMS, an energy storage PCS, a direct cooling unit, and a temperature and humidity tester arranged in an energy storage cabinet. The control system is a direct cooling and heat control system based on refrigerant, and the refrigerant is refrigerant R410A, an environmentally friendly refrigerant. The energy storage BMS is used to collect the temperature of the battery cells in real time, the energy storage PCS is used to collect the electrical parameters of the energy storage battery system in real time, and the temperature and humidity tester is used to detect the ambient temperature and humidity in the energy storage cabinet in real time. The energy storage BMS, the energy storage PCS, and the temperature and humidity tester all transmit the collected data to the energy storage EMS. The energy storage EMS stores different temperature control strategies for different active power ranges of the energy storage battery system. The energy storage EMS performs multi-level judgments based on the received data and the corresponding temperature control strategies, and controls the direct cooling unit to enter the corresponding temperature control measures based on the judgment results. For the specific temperature control process, see Figure 1 shown.

[0024] Energy storage EMS enters the first level of judgment: The energy storage EMS obtains the active power P of the energy storage battery system according to the received electrical parameters, and determines the active power interval in which the active power P is located according to the obtained active power P. In this embodiment, the energy storage EMS stores four active power intervals, including (0, 1 / 3P]; (1 / 3P, 1 / 2P]; (1 / 2P, 2 / 3P]; (2 / 3P, P], and four different temperature control strategies correspond to the four active power intervals. After determining the active power interval, the energy storage EMS selects the temperature control strategy in the corresponding interval as the current operating temperature control strategy.

[0025] The energy storage EMS checks whether its communication connection with the energy storage BMS is normal: If not, the direct cooling unit performs temperature control with its own collected temperature. Specifically, the direct cooling unit collects the current ambient temperature through its own ambient temperature sensor, and compares it with its preset cooling point or heating point. If the current ambient temperature is higher than the cooling point, the direct cooling unit enters the cooling mode; if the current ambient temperature is lower than the heating point, the direct cooling unit enters the heating mode; if the current ambient temperature is between the cooling point and the heating point, the direct cooling unit shuts down.

[0026] If so, the energy storage EMS checks whether the direct cooling unit is shut down, and makes judgments and takes corresponding temperature control measures according to its different working states.

[0027] If the direct cooling unit is in shutdown state, the energy storage EMS enters the second level judgment; Second level judgment: The temperature control strategy includes the optimal operating temperature range of the battery cell. The energy storage EMS determines whether the received battery cell temperature data is within the optimal operating temperature range under the corresponding active power. If so, it means that the temperatures of all battery cells are within the optimal operating temperature range, and the energy storage EMS enters the third level judgment.

[0028] If not, the energy storage EMS controls the direct cooling unit to cool or heat. Specifically, the two endpoint values ​​of the working temperature range are the cooling point and the heating point, respectively. The heating point temperature ≤ working temperature ≤ cooling point temperature. The energy storage EMS identifies and obtains the highest and lowest temperatures in all received battery cell temperature data, and compares the highest battery cell temperature with the cooling point under the corresponding active power. If the highest battery cell temperature is greater than or equal to the cooling point temperature, the energy storage EMS issues a cooling instruction to the direct cooling unit; if the highest battery cell temperature is less than the cooling point temperature, the energy storage EMS further compares the lowest battery cell temperature with the heating point under the corresponding active power. If the lowest battery cell temperature is less than or equal to the heating point temperature, the energy storage EMS issues a heating instruction to the direct cooling unit; if the lowest battery cell temperature is greater than the heating point temperature, it indicates that all battery cell temperatures are within the optimal working temperature range.

[0029] The third level of judgment: The temperature control strategy also includes the permissible range of temperature difference between each battery cell. The energy storage EMS identifies and obtains the highest and lowest temperatures from all the battery cell temperature data received, and calculates the maximum temperature difference between the groups. It then determines whether the obtained maximum temperature difference between the groups is within the permissible range of temperature difference between the groups under the corresponding active power. If so, the energy storage EMS enters the fourth level of judgment.

[0030] If not, the energy storage EMS controls the direct cooling unit for cooling or heating. Specifically, a preset temperature threshold is stored in the energy storage EMS. The energy storage EMS takes the average of all received battery cell temperature data and compares it with the temperature threshold. If the maximum temperature difference between groups is greater than or equal to the temperature threshold, the energy storage EMS issues a cooling command to the direct cooling unit; if the average battery cell temperature is less than the temperature threshold, the energy storage EMS issues a heating command to the direct cooling unit.

[0031] Fourth level judgment: The energy storage EMS stores the allowable range of ambient temperature. After the temperature and humidity tester sends the real-time collected ambient temperature data to the energy storage EMS, the energy storage EMS determines whether the current ambient temperature is within the allowable range. If yes, the energy storage EMS will issue a shutdown command to the direct cooling unit. Since the direct cooling unit is in shutdown state at this time, it ends. At this time, the ambient temperature is within the allowable range of ambient temperature, so the ambient temperature has little effect on the temperature of the battery cell, and there is no need to use the direct cooling system for additional regulation.

[0032] If not, the energy storage EMS controls the direct cooling unit to cool or heat. Specifically, if the current ambient temperature is higher than or equal to the maximum allowable ambient temperature, that is, it is in a high temperature environment, the energy storage EMS issues a cooling command to the direct cooling unit; if the current ambient temperature is lower than or equal to the minimum allowable ambient temperature, that is, it is in a low temperature environment, the energy storage EMS issues a heating command to the direct cooling unit. Since the battery cell is in a high or low temperature environment, the external temperature will have a greater temperature impact on the battery cell. Therefore, through the regulation of the direct cooling unit, it can be ensured that the battery cell can still remain in the optimal working range even in a high or low temperature environment, which is conducive to extending the service life of the battery cell. At the same time, it can also avoid thermal runaway, resulting in battery damage or even explosions and fires and other serious safety accidents.

[0033] If the direct cooling unit is in the on state: The temperature control strategy also includes the evaporation and condensation temperature set values ​​of the direct cooling unit. The direct cooling unit sends the real-time evaporation temperature and condensation temperature data to the energy storage EMS. The energy storage EMS compares the received evaporation temperature and condensation temperature data with the evaporation and condensation temperature set values ​​under the corresponding active power to determine whether the two continue to meet the evaporation / condensation requirements within the specified time. The specific evaporation / condensation requirements are: evaporation temperature ≤ evaporation and condensation temperature set value or condensation temperature ≥ evaporation and condensation temperature set value; If it can last for at least ten minutes while meeting the evaporation / condensation requirements, it means that the operating state of the direct cooling unit has reached stability, and the current cooling or heating effect can meet and maintain the temperature requirements of the energy storage system. The energy storage EMS will then issue a shutdown command to the direct cooling unit to improve the overall energy efficiency of the system and reduce energy consumption.

[0034] If the evaporation / condensation requirements are not met or it cannot last for ten minutes under the condition that the evaporation / condensation requirements are met, the energy storage EMS begins to determine whether the working mode of the direct cooling unit is cooling or heating mode. If it is cooling mode, the energy storage EMS receives all battery cell temperature data and identifies and obtains the highest battery cell temperature, and then compares it with the cooling point temperature under the corresponding active power: if the highest battery cell temperature is greater than or equal to the cooling point temperature, the energy storage EMS issues a cooling command to the direct cooling unit. Since the direct cooling unit is in cooling mode at this time, it ends; if the highest battery cell temperature is lower than the cooling point temperature, the third and fourth levels are entered in turn for judgment.

[0035] If it is in heating mode, the energy storage EMS receives all the battery cell temperature data, identifies and obtains the lowest battery cell temperature, and then compares it with the heating point temperature under the corresponding active power: if the highest battery cell temperature is less than or equal to the heating point temperature, the energy storage EMS issues a heating command to the direct cooling unit. Since the direct cooling unit is in heating mode at this time, it ends; if the highest battery cell temperature is greater than the cooling point temperature, the third and fourth levels are entered in turn for judgment.

[0036] The battery temperature control system of the present invention can realize precise control of the battery temperature through the joint control of the direct cooling unit by the energy storage EMS, energy storage BMS and energy storage PCS. At the same time, the control system adopts multi-level judgment, which can make multi-aspect judgments on the active power of the energy storage battery, the temperature of the battery cell itself, the temperature between groups and the ambient temperature, and can effectively ensure that the battery cell temperature is always within the optimal temperature range. Compared with the traditional liquid cooling technology control strategy, the control system can greatly extend the life of the battery system, improve the stability of the battery system, effectively avoid thermal runaway of the battery cell, effectively avoid the ineffective energy consumption of the direct cooling unit, etc., and realize multi-faceted optimization.

[0037] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A temperature control system for an energy storage battery, characterized in that: It includes energy storage EMS, energy storage BMS, energy storage PCS and direct cooling unit. The energy storage BMS is used to collect the temperature of the battery cell in real time, and the energy storage PCS is used to collect the electrical parameters of the energy storage battery system in real time. The energy storage BMS and energy storage PCS transmit the collected temperature data and electrical parameters to the energy storage EMS. The energy storage EMS obtains the active power of the energy storage battery system according to the received electrical parameters. The energy storage EMS stores different temperature control strategies under different active power ranges. The energy storage EMS performs multi-level judgments based on the received battery cell temperature data and the corresponding temperature control strategies, and controls the direct cooling unit to enter the corresponding temperature control measures according to the judgment results.

2. The temperature control system according to claim 1, characterized in that: The energy storage EMS takes corresponding control measures on the direct cooling unit according to the working status of the direct cooling unit; If it is in the on state, the energy storage EMS controls the direct cooling unit to enter the corresponding temperature control measures according to the current evaporation or condensation temperature of the direct cooling unit and the corresponding temperature control strategy; If it is in shutdown state, the energy storage EMS controls the direct cooling unit to enter corresponding temperature control measures based on the collected battery cell temperature data and the corresponding temperature control strategy.

3. The temperature control system according to claim 2, characterized in that: The energy storage EMS enters the first level of judgment according to the active power of the energy storage battery system. The first level is to judge the corresponding active power interval in which the active power of the energy storage battery system is located, and select the temperature control strategy under the corresponding interval. The energy storage EMS enters the second level of judgment according to the selected temperature control strategy and the collected battery cell temperature data.

4. The temperature control system according to claim 3, characterized in that: The temperature control strategy includes the operating temperature range of the battery cell, and the second level is to determine whether the temperature of each battery cell is within the operating temperature range under the corresponding active power; If yes, the energy storage EMS enters the third level of judgment; If not, the energy storage EMS controls the direct cooling unit to perform cooling or heating.

5. The temperature control system according to claim 4, characterized in that: The temperature control strategy also includes the allowable range of temperature difference between different battery cells. The energy storage EMS identifies and obtains the highest temperature and the lowest temperature in all the received battery cell temperature data, and calculates the maximum temperature difference between groups. The third level is to determine whether the maximum temperature difference between groups is within the allowable range of temperature difference between groups under the corresponding active power. If yes, the energy storage EMS enters the fourth level of judgment; If not, the energy storage EMS controls the direct cooling unit to perform cooling or heating.

6. The temperature control system according to claim 5, characterized in that: It also includes a temperature and humidity tester arranged in the energy storage cabinet, which is used to detect the ambient temperature and humidity in the energy storage cabinet in real time, and transmit the measured ambient temperature data to the energy storage EMS, which stores the allowable range of ambient temperature. The fourth level is to determine whether the received ambient temperature is within the allowable range of ambient temperature; If so, the energy storage EMS issues a shutdown command to the direct cooling unit; If not, the energy storage EMS controls the direct cooling unit to perform cooling or heating.

7. The temperature control system according to claim 6, characterized in that: The temperature control strategy also includes the evaporation and condensation temperature target value of the direct cooling unit. When the direct cooling unit is turned on, the direct cooling unit sends its real-time evaporation temperature and condensation temperature data to the energy storage EMS. The energy storage EMS receives the evaporation temperature and condensation temperature data and compares them with the evaporation and condensation temperature target values ​​under the corresponding active power, respectively, to determine whether the two continuously meet the evaporation / condensation requirements within the specified time; the evaporation / condensation requirements are: evaporation temperature ≤ evaporation and condensation temperature target value or condensation temperature ≥ evaporation and condensation temperature target value; If it can last for at least ten minutes while meeting the evaporation / condensation requirements, the energy storage EMS will issue a shutdown command to the direct cooling unit; If the evaporation / condensation requirements are not met or it cannot last for ten minutes under the condition that the evaporation / condensation requirements are met, the energy storage EMS begins to determine whether the working mode of the direct cooling unit is cooling or heating mode. If it is cooling mode, the energy storage EMS receives all battery cell temperature data, identifies and obtains the highest battery cell temperature, and compares it with the cooling point temperature under the corresponding active power: if the highest battery cell temperature ≥ the cooling point temperature, the energy storage EMS issues a cooling instruction to the direct cooling unit; if the highest battery cell temperature < the cooling point temperature, it enters the third level of judgment, and controls the direct cooling unit to take corresponding temperature control measures according to the judgment result; If it is in heating mode, the energy storage EMS receives all the battery cell temperature data, identifies and obtains the lowest battery cell temperature, and compares it with the heating point temperature under the corresponding active power: if the lowest battery cell temperature is ≤ the cooling point temperature, the energy storage EMS issues a heating command to the direct cooling unit; if the highest battery cell temperature is greater than the cooling point temperature, it enters the third level of judgment, and controls the direct cooling unit to take corresponding temperature control measures based on the judgment results.

8. The temperature control system according to claim 4, characterized in that: The two endpoints of the operating temperature range are the cooling point and the heating point, respectively, and the heating point ≤ the operating temperature ≤ the cooling point; the energy storage EMS identifies and obtains the highest temperature and the lowest temperature from all the received battery cell temperature data, and compares the highest battery cell temperature with the cooling point under the corresponding active power: If the highest cell temperature is ≥ the cooling point temperature, the energy storage EMS will issue a cooling command to the direct cooling unit; If the maximum cell temperature is less than the cooling point temperature, the energy storage EMS will compare the minimum cell temperature with the heating point under the corresponding active power; If the lowest cell temperature is ≤ the heating point temperature, the energy storage EMS will issue a heating command to the direct cooling unit; If the lowest cell temperature is greater than the hot spot temperature, the energy storage EMS enters the third level of judgment.

9. The temperature control system according to claim 5, characterized in that: The energy storage EMS stores a preset temperature threshold. If the maximum temperature difference between groups does not meet the allowable range of the temperature difference between groups under the corresponding active power or the current ambient temperature does not meet the allowable range of the ambient temperature, the energy storage EMS takes the average of all the received battery cell temperature data and compares it with the temperature threshold: If the average cell temperature is ≥ the temperature threshold, the energy storage EMS issues a cooling command to the direct cooling unit; If the average cell temperature is less than the temperature threshold, the energy storage EMS will issue a heating command to the direct cooling unit.

10. The temperature control system according to claim 6, characterized in that: When the ambient temperature received by the energy storage EMS does not meet the allowable ambient temperature range, the energy storage EMS compares the received ambient temperature with the maximum allowable ambient temperature and the minimum allowable ambient temperature: If the ambient temperature is ≥ the maximum allowable ambient temperature, that is, it is in a high temperature environment, the energy storage EMS will issue a cooling command to the direct cooling unit; If the ambient temperature is ≤ the minimum allowable ambient temperature, that is, it is in a low temperature environment, the energy storage EMS will issue a heating command to the direct cooling unit.

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