Energy storage battery compartment temperature control method, system, device, and medium

Abstract

This invention relates to the field of thermal management technology for large-scale energy storage battery systems, and discloses a method, system, device, and medium for temperature control of an energy storage battery compartment. The method includes: real-time monitoring of the cell temperature and state of charge (SOC) of each cell within the battery compartment; adjusting the preset liquid cooler outlet water temperature to control the cell temperature within a first temperature range based on the SOC during the charging phase; adjusting the liquid cooler outlet water temperature to control the cell temperature within a second temperature range during the discharging phase; and real-time monitoring of the temperature difference between cells within the battery compartment, using a forced temperature equalization control mode to reduce the temperature difference between cells. This invention can effectively improve the charging and discharging efficiency of the battery compartment and reduce temperature fluctuations.

Description

Technical Field

[0001] This invention relates to the field of thermal management technology for large-scale energy storage battery systems, specifically to a method, system, device, and medium for controlling the temperature of an energy storage battery compartment. Background Technology

[0002] The traditional liquid cooling system uses a fixed temperature threshold control strategy, which leads to large temperature fluctuations (temperature difference of 7-8℃) in the cells during charging and discharging, affecting the consistency of cell activity. Uneven temperature management during charging and discharging results in a phenomenon of "high charging temperature and low discharging temperature", causing efficiency loss of "more charging and less discharging". The coordination between the BMS (Battery Management System) and the liquid cooling system is insufficient. Currently, the BMS only issues start-up temperature commands, and the liquid cooler adjusts its operating mode autonomously, making it difficult to achieve precise temperature control.

[0003] In the prior art, the invention patent with application number 202510568191.X discloses a control method based on the working status and temperature data of the battery cells. Its core is to control based on temperature difference when all battery cell temperatures are within the safe range, and to control based on maximum difference when there is abnormal battery cell temperature. However, the temperature balance control is a safety-oriented, fuzzy, and undifferentiated conventional mode adjustment, which is only an auxiliary means of battery cell safety temperature control and does not consider the need to improve the cycle efficiency of the energy storage battery compartment.

[0004] The invention patent with application number 202411267919.7 discloses a battery management system (BMS). It determines the current state of the battery (charging, discharging, or standby) based on the output power of the energy storage converter (PCS). It also sends corresponding instructions to the liquid cooling unit controller (TMS) based on the cell temperature collected by the temperature sensor to control the liquid cooling unit to enter heating mode, cooling mode, self-circulation mode, or shutdown mode. However, the core function is only to ensure the safety of the cell temperature and avoid overheating or overcooling. It does not take improving the cycle efficiency (RTE) of the energy storage battery compartment as the core objective, does not establish a direct correlation between temperature and RTE, and cannot solve the efficiency loss problem of "charging more and discharging less".

[0005] In conclusion, improving the charging and discharging efficiency of the battery compartment, reducing temperature fluctuations, and ensuring that the battery operates within its optimal temperature range are urgent problems to be solved. Summary of the Invention

[0006] The technical problem to be solved by this invention is how to improve the charging and discharging efficiency of the battery compartment, reduce temperature fluctuations, and ensure that the battery operates within the optimal temperature range.

[0007] The present invention solves the above-mentioned technical problems through the following technical means:

[0008] Real-time monitoring of cell temperature and state of charge of each cell in the battery compartment; When the battery compartment is in the charging stage, the cell temperature is controlled in the first temperature range by adjusting the preset liquid cooler outlet water temperature according to the state of charge. When the battery compartment is in the discharge stage, the temperature of the battery cell is controlled in the second temperature range by adjusting the outlet water temperature of the liquid cooler according to the state of charge. The temperature difference between the cells in the battery compartment is monitored in real time, and the temperature difference between the cells is reduced by using a forced temperature equalization control mode based on the temperature difference between the cells.

[0009] Optionally, the step of adjusting the preset liquid chiller outlet water temperature according to the state of charge to control the cell temperature within a first temperature range includes: When the state of charge is less than or equal to a first preset value, the outlet water temperature of the liquid chiller is controlled to be the minimum value of the first temperature range; When the state of charge is greater than the first preset value and less than or equal to the second preset value, the outlet water temperature of the liquid chiller is gradually increased according to the state of charge. When the state of charge is greater than the second preset value, the outlet water temperature of the liquid chiller is maintained at the maximum value of the first temperature range.

[0010] Optionally, when the battery compartment is in the discharge phase, before adjusting the outlet water temperature of the liquid cooler according to the state of charge to control the cell temperature in the second temperature range, the method further includes: The outlet water temperature of the liquid cooler is preheated to a preset preheating temperature, and the battery compartment is preheated using the preheating temperature.

[0011] Optionally, the second temperature range is [35℃, 38.5℃].

[0012] Optionally, the forced temperature equalization control mode includes: forcibly starting the cooling mode or heating mode of the liquid chiller, and dynamically adjusting the operating frequency of the variable frequency water pump to reduce the temperature difference between the battery cells.

[0013] Optionally, the energy storage battery compartment temperature control method is applied to the energy storage battery compartment temperature control system, the energy storage battery compartment temperature control system comprising: Temperature detection module is used to monitor the cell temperature of each cell in the battery compartment in real time; The BMS control module is used to monitor the state of charge of each cell in the battery compartment and the temperature difference between the cells in the battery compartment in real time. Liquid chiller module, including liquid chiller.

[0014] Optionally, the BMS control module is communicatively connected to the liquid chiller module and can directly control the operating mode of the liquid chiller module based on temperature detection data.

[0015] Optionally, the temperature detection module is arranged with one temperature acquisition point for every two battery cells; The BMS control unit communicates with the liquid cooling unit using the RS485 protocol.

[0016] The present invention also provides a processing device, characterized in that it includes at least one processor and at least one memory communicatively connected to the processor, wherein: the memory stores program instructions executable by the processor, and the processor can execute the above-described method for controlling the temperature of the energy storage battery compartment by calling the program instructions.

[0017] The present invention also provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions, the computer instructions causing the computer to execute the above-described method for controlling the temperature of the energy storage battery compartment.

[0018] The advantages of this invention are: This invention achieves fine-grained segmented adjustment based on SOC by using different target temperature ranges (32-38℃ for charging and 35-38.5℃ for discharging) during the State of Charge (SOC) charging and discharging stages. This enables differentiated and precise temperature control during the charging and discharging process, resulting in a smoother temperature rise during charging, avoiding localized overheating, increasing discharge energy, reducing the temperature range from 7-8℃ to ≤5℃, and ensuring that the battery cell remains in a highly active state before discharging. As a result, the cycle efficiency (RTE) is increased from 92% to 94.2%, and the charge / discharge efficiency fluctuation is less than 1.5%, effectively improving the charge / discharge efficiency of the battery compartment and reducing temperature fluctuations. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of a method for controlling the temperature of an energy storage battery compartment in one embodiment of the present invention; Figure 2 This is a comparison chart of the temperature curves of the battery compartment before and after temperature control optimization in one embodiment of the present invention; Figure 3 This is a schematic diagram of the architecture of the temperature control system for an energy storage battery compartment according to the present invention. Figure 4 This is a timing diagram of BMS-liquid chiller coordinated control in one embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Reference Figure 1 The diagram shown is a schematic flowchart of a method for controlling the temperature of an energy storage battery compartment according to an embodiment of the present invention. In this embodiment, the method for controlling the temperature of the energy storage battery compartment includes: S1. Real-time monitoring of cell temperature and state of charge of each cell in the battery compartment.

[0022] In this embodiment of the invention, a 5MWH energy storage battery compartment can be used as the implementation object. The specific hardware components are as follows: Battery system, cell specifications: 314Ah lithium iron phosphate cells, rated voltage 3.2V. System architecture 12P416S, each PACK (battery pack / module) has 52 temperature sensing sampling points, sensor type: PT100 platinum resistance thermometer (accuracy ±0.3℃).

[0023] Temperature control system, liquid chiller cooling capacity: 60kW (±0.5℃ accuracy), using variable frequency centrifugal pump (30-100Hz adjustable), piping system adopts parallel double circulation loop design.

[0024] Control system: BMS main controller, using an ARM Cortex-M7 processor, communication interface: MODBUS-RTU (RS485), control cycle: 500ms. Equipped with a human-machine interface, a 7-inch touchscreen (real-time display of temperature field distribution).

[0025] In detail, the battery compartment includes multiple battery modules, each containing several 314Ah cells; the total capacity of the battery compartment is 5MWH or more, and the temperature and state of charge (SOC) of each cell can be monitored in real time through a pre-built temperature detection module.

[0026] S2. When the battery compartment is in the charging stage, the cell temperature is controlled in the first temperature range by adjusting the preset liquid cooler outlet water temperature according to the state of charge.

[0027] In this embodiment of the invention, the charging state refers to the external input of power to the battery compartment, and the dynamic adjustment of the liquid cooler outlet water temperature according to the SOC value to control the cell temperature within the first temperature range [32℃, 38℃].

[0028] Specifically, adjusting the preset water outlet temperature of the liquid chiller according to the state of charge to control the cell temperature within the first temperature range includes: When the state of charge is less than or equal to the first preset value, controlling the water outlet temperature of the liquid chiller to be the minimum value of the first temperature range; When the state of charge is greater than the first preset value and less than or equal to the second preset value, gradually increasing the water outlet temperature of the liquid chiller according to the state of charge; When the state of charge is greater than the second preset value, maintaining the water outlet temperature of the liquid chiller at the maximum value of the first temperature range.

[0029] Specifically, the first preset value is 30% and the second preset value is 70%. During the charging stage control, when SOC ≤ 30%: the water outlet temperature of the liquid chiller is set to 32°C to avoid the influence of low temperature on the lithium ion migration rate, and the pump frequency is fixed at 40 Hz; when 30% < SOC ≤ 70%: for every 10% SOC increase, the temperature is increased by 1°C (e.g., when 40% SOC → 33°C), and the pump frequency increases linearly (40 → 70 Hz); when SOC > 70%: maintain the water outlet temperature at 38°C, and the pump frequency is dynamically adjusted according to the range, with gradient temperature increase to match the change in the internal resistance of the cell.

[0030] if (T_max - T_min>3) { pump_freq += 10; / / The pump frequency increases by 10 Hz cool_power = (T_avg - 38.5) 2.5; / / PID control } Specifically, In the embodiment of the present invention, during the charging stage, according to the SOC value (≤ 30%, 30 - 70%, > 70%), the water outlet temperature is dynamically adjusted, with a 1°C increase for every 10% SOC. This gradient temperature increase strategy matches the variation law of the internal resistance of the cell with SOC, can accurately control the temperature rise, and achieve refined stage control based on SOC.

[0031] S3. When the battery compartment is in the discharging stage, adjust the water outlet temperature of the liquid chiller according to the state of charge to control the cell temperature within the second temperature range.

[0032] In the embodiment of the present invention, the charging state refers to the external output power to the battery compartment. The water outlet temperature of the liquid chiller is dynamically adjusted according to the SOC value to control the cell temperature within the range of the second temperature range [35°C, 38.5°C].

[0033] Specifically, the method further includes, before adjusting the outlet water temperature of the liquid cooler to control the cell temperature within a second temperature range according to the state of charge during the discharge phase of the battery compartment: The outlet water temperature of the liquid cooler is preheated to a preset preheating temperature, and the battery compartment is preheated using the preheating temperature.

[0034] In one optional embodiment of the present invention, the outlet water temperature of the liquid cooler can be preheated to a preset preheating temperature of 37°C 30 minutes before the battery compartment is in the discharge stage, so as to preheat the battery compartment and ensure that the battery cells reach the optimal operating temperature.

[0035] Furthermore, during the battery compartment's discharge phase, the outlet water temperature of the liquid cooler is maintained at 38±0.5℃ to reduce the impact of temperature fluctuations on RTE (Round Trip Efficiency). If the temperature of a certain cell exceeds 39℃, the BMS will forcibly activate the liquid cooler for cooling.

[0036] In this embodiment of the invention, preheating solves the problem of a sharp drop in low-temperature discharge efficiency, thereby increasing the discharge energy and improving RTE by 2.2%.

[0037] S4. Monitor the temperature difference between cells in the battery compartment in real time, and reduce the temperature difference between cells using a forced temperature equalization control mode based on the temperature difference between cells.

[0038] In this embodiment of the invention, the temperature difference between cells in the battery compartment refers to the difference between the highest and lowest temperatures among all cells in the battery compartment. The temperature difference between cells can be calculated based on the BMS (Battery Management System) and control commands for a forced temperature equalization control mode can be generated.

[0039] Specifically, when the temperature difference between the cells inside the cabin exceeds 5°C, the forced temperature equalization control mode is activated. The forced temperature equalization control mode includes: the BMS forcibly activating the cooling or heating mode of the liquid chiller and dynamically adjusting the operating frequency of the variable frequency water pump to reduce the temperature difference to within 5°C.

[0040] Furthermore, in the forced temperature equalization control mode, the dynamic adjustment of the operating frequency of the variable frequency water pump is specifically as follows: the water pump frequency is adjusted linearly or proportionally according to the size of the temperature difference. The larger the temperature difference, the higher the frequency. The water pump frequency adjustment range is 30-100Hz.

[0041] In this embodiment of the invention, through a forced collaborative mechanism between the BMS (Battery Management System) and the liquid cooler, combined with refined hardware configuration, the system response speed is improved from passive response >5s to active intervention <2s, the temperature difference is controlled within 5℃, and the first-test pass rate in mass production is increased from 50% to 85%, resulting in significant economic benefits. The temperature curve comparison of the battery compartment before and after temperature control optimization is shown in the figure below. Figure 2 As shown.

[0042] For example, in the discharge stage control, during the preheating stage (30 minutes before discharge): the liquid chiller switches to heating mode, the outlet water temperature is 37℃ (±0.5℃), and the water pump frequency is 60Hz; during the constant temperature discharge stage: the temperature control target is 38.5℃, and when the range is >3℃, the water pump frequency is increased to 10Hz.

[0043] Abnormal handling mechanism: Temperature exceeds limit (single cell > 40℃): Emergency cooling is immediately activated, reducing the charging current by 50%; Range exceeds standard (> 5℃ for 10 seconds): Forced equalization mode is triggered, increasing the module liquid cooling flow by 30%; Range > 7℃ for 1 minute: Shutdown for maintenance.

[0044] The key parameters for implementing the control method are shown in Table 1 below: Table 1

[0045] The verification data for the battery compartment charging process is shown in Table 2 below: Table 2

[0046] The verification data for the battery compartment discharge process are shown in Table 3 below: Table 3

[0047] The actual application verification data of the battery compartment is shown in Table 4 below: Table 4

[0048] This solution, through experiments, revealed that the battery cell exhibits optimal activity within the 28-40℃ range. A higher and more stable temperature environment is required during the discharge phase, which is crucial for improving Real-Time Efficiency (RTE). The optimized solution improves RTE by 2.2%, increases the mass production yield to over 85%, and demonstrates significant economic benefits. Furthermore, the BMS (Battery Management System) enforces control, effectively enhancing response speed, and the addition of preheating reduces efficiency loss.

[0049] like Figure 3The diagram shown is a functional block diagram of an energy storage battery compartment temperature control system provided in an embodiment of the present invention. The energy storage battery compartment temperature control method is applied to the energy storage battery compartment temperature control system.

[0050] Specifically, the energy storage battery compartment temperature control system includes: Temperature detection module is used to monitor the cell temperature of each cell in the battery compartment in real time; The BMS control module is used to monitor the state of charge of each cell in the battery compartment and the temperature difference between the cells in the battery compartment in real time. Liquid chiller module, including liquid chiller.

[0051] In detail, the liquid chiller in the liquid chiller unit module can be represented as a temperature regulating device, so that the outlet water temperature of the liquid chiller is adjustable in the range of 20-45℃; the liquid chiller unit module also includes a variable frequency water pump, the frequency of which is adjustable in the range of 30-100Hz.

[0052] In detail, the energy storage battery compartment temperature control system is as follows: Figure 3 The energy storage battery compartment system is as follows: The BMS control module is... Figure 3 The BMS main control unit and the liquid chiller module are... Figure 3 The liquid-cooled unit in the middle, the battery compartment is Figure 3 The battery system in it.

[0053] The BMS control module is communicatively connected to the liquid chiller module and can directly control the operating mode of the liquid chiller module based on temperature detection data.

[0054] Furthermore, the BMS control module is configured as follows: When the temperature difference between the cells exceeds 5°C, the liquid cooler is forcibly activated in either cooling or heating mode; the pump circulation frequency (30-100Hz) is dynamically adjusted to optimize the coolant flow rate; and a preheating program is initiated 30 minutes before discharge.

[0055] The temperature detection modules are arranged at a density of one temperature acquisition point for every two battery cells; the BMS control unit communicates with the liquid cooling unit using the RS485 protocol.

[0056] The energy storage battery compartment temperature control system employs a BMS-liquid cooler forced collaborative mode. By real-time acquisition of cell temperature and SOC, it forcibly activates the liquid cooler for cooling / heating, dynamically adjusting the pump circulation frequency (30-100Hz). A temperature-efficiency mapping database is established to automatically select the optimal operating mode. For details, please refer to [reference needed]. Figure 4 The diagram shown represents the timing diagram of the BMS-liquid chiller coordinated control.

[0057] The specific execution methods for the steps in each of the above modules are the same as the corresponding execution steps in the above energy storage battery compartment temperature control method.

[0058] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the temperature of an energy storage battery compartment, characterized in that, include: Real-time monitoring of cell temperature and state of charge of each cell in the battery compartment; When the battery compartment is in the charging stage, the cell temperature is controlled in the first temperature range by adjusting the preset liquid cooler outlet water temperature according to the state of charge. When the battery compartment is in the discharge stage, the temperature of the battery cell is controlled in the second temperature range by adjusting the outlet water temperature of the liquid cooler according to the state of charge. The temperature difference between the cells in the battery compartment is monitored in real time, and the temperature difference between the cells is reduced by using a forced temperature equalization control mode.

2. The energy storage battery compartment temperature control method as described in claim 1, characterized in that, The step of adjusting the preset liquid chiller outlet water temperature according to the state of charge to control the cell temperature within a first temperature range includes: When the state of charge is less than or equal to a first preset value, the outlet water temperature of the liquid chiller is controlled to be the minimum value of the first temperature range; When the state of charge is greater than the first preset value and less than or equal to the second preset value, the outlet water temperature of the liquid chiller is gradually increased according to the state of charge. When the state of charge is greater than the second preset value, the outlet water temperature of the liquid chiller is maintained at the maximum value of the first temperature range.

3. The energy storage battery compartment temperature control method as described in claim 1, characterized in that, The method further includes, when the battery compartment is in the discharge phase, adjusting the outlet water temperature of the liquid cooler according to the state of charge to control the cell temperature before the second temperature range, the method further includes: The outlet water temperature of the liquid cooler is preheated to a preset preheating temperature, and the battery compartment is preheated using the preheating temperature.

4. The energy storage battery compartment temperature control method as described in claim 1, characterized in that, The second temperature range is [35℃, 38.5℃].

5. The energy storage battery compartment temperature control method as described in claim 1, characterized in that, The forced temperature equalization control mode includes: forcibly starting the cooling mode or heating mode of the liquid chiller, and dynamically adjusting the operating frequency of the variable frequency water pump to reduce the temperature difference between the battery cells.

6. The energy storage battery compartment temperature control system as described in claim 1, characterized in that, The energy storage battery compartment temperature control method according to any one of claims 1-5, wherein the energy storage battery compartment temperature control system comprises: Temperature detection module is used to monitor the cell temperature of each cell in the battery compartment in real time; The BMS control module is used to monitor the state of charge of each cell in the battery compartment and the temperature difference between the cells in the battery compartment in real time. Liquid chiller module, including liquid chiller.

7. The energy storage battery compartment temperature control system as described in claim 6, characterized in that, The BMS control module is communicatively connected to the liquid chiller module and can directly control the operating mode of the liquid chiller module based on temperature detection data.

8. The energy storage battery compartment temperature control system as described in claim 6, characterized in that, The temperature detection module is arranged with one temperature acquisition point for every two battery cells. The BMS control unit communicates with the liquid cooling unit using the RS485 protocol.

9. A processing device, characterized in that, It includes at least one processor and at least one memory communicatively connected to the processor, wherein: the memory stores program instructions executable by the processor, and the processor can execute the method as described in any one of claims 1-5 by invoking the program instructions.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause the computer to perform the method as described in any one of claims 1-5.

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