A kind of cell-level intelligent temperature control method for liquid-cooled energy storage device and liquid-cooled energy storage device

Abstract

A kind of cell level intelligent temperature control method for liquid-cooled energy storage device and liquid-cooled energy storage device, its liquid cooling unit includes: evaporator, compressor, condenser and expansion valve, form refrigeration circuit;Battery cluster includes multiple battery packs, electronic flow switch is arranged on the liquid cooling branch of each battery pack, the liquid inlet of each liquid cooling branch is connected to the output end of variable frequency liquid pump, after the liquid outlet is converged and enters variable frequency liquid pump again after the evaporator of liquid cooling unit, form liquid cooling circuit, each liquid cooling branch can be independently operated in refrigeration mode, heating mode or standby mode;The present application can effectively realize the temperature accurate control of battery pack, save energy according to the start-stop of heating system and cooling system controlled by battery temperature.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, and more specifically, relates to a cell-level intelligent temperature control method and a liquid-cooled energy storage device. Background Technology

[0002] In recent years, energy storage battery systems have been widely used in power systems due to their advantages such as high capacity, long lifespan, and high transmission efficiency. However, traditional energy storage liquid cooling systems consume a large amount of electrical energy during operation, leading to reduced system efficiency. Especially when thermal management systems are in operation, the energy consumption of devices such as air conditioners, liquid chillers, and cooling fans increases significantly.

[0003] Furthermore, existing liquid cooling systems typically rely on a single temperature sensor to report outlet water temperature data for mode switching. This method struggles to comprehensively reflect the actual temperature conditions inside the battery pack, resulting in insufficient accuracy and consistency in temperature control. In standby or shutdown states, the reduced frequency of temperature detection may also lead to undetected temperature anomalies, affecting the system's response speed and accuracy. Specifically, the shortcomings of existing technologies include: (1) Battery temperature regulation may result in slow response or over-regulation, affecting the overall efficiency of the energy storage system: Liquid cooling systems generally use battery temperature as the control target. When the battery temperature is too high, the liquid cooling system is activated to dissipate heat; when the battery temperature is too low, the heating system is activated. However, the control logic of this operation mode is relatively simple and cannot adjust the operation strategy of the liquid cooling system in real time according to the heat load change trend of the battery system. (2) Due to the sequential nature of heat interaction caused by the laying structure of liquid cooling pipes, the dynamic nature of individual cell temperature and the uneven temperature distribution, starting by judging the highest and lowest temperatures and setting fixed values ​​will lead to low efficiency, malfunctions caused by temperature acquisition errors, etc.

[0004] Therefore, existing technologies need to improve control precision when dealing with complex operating conditions and emergencies. This not only affects the working efficiency of energy storage batteries but may also bring potential safety hazards. Improving existing liquid cooling systems through refined temperature monitoring and intelligent control strategies to achieve self-adjustment of cooling power consumption and ensure the efficient and safe operation of the system is particularly important. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a cell-level intelligent temperature control method and a liquid-cooled energy storage device for liquid-cooled energy storage devices. This method optimizes the control strategy of the liquid-cooled energy storage system, improves control accuracy, reduces the cost of the cooling system, increases the working efficiency of the energy storage battery, and ensures efficient and safe operation of the system. The goal is to achieve refined temperature control of the energy storage system and optimized energy consumption of the liquid-cooled system.

[0006] The present invention adopts the following technical solution.

[0007] A first aspect of the present invention provides a liquid-cooled energy storage device, comprising: a liquid-cooling unit and a battery cluster; the liquid-cooling unit includes: an evaporator, a compressor, a condenser, and an expansion valve, forming a refrigeration circuit; the battery cluster includes multiple battery packs, each battery pack having an electronic flow switch installed on its liquid-cooling branch, the inlet of each liquid-cooling branch being connected to the output of a variable frequency infusion pump, and the liquid flowing from the outlet converging and passing through the evaporator of the liquid-cooling unit before re-entering the variable frequency infusion pump, forming a liquid-cooling circuit; each liquid-cooling branch can operate independently in a cooling mode, a heating mode, or a standby mode; the battery pack starts or exits the heating mode based on the minimum and average temperatures collected from all cells in each battery pack, and starts or exits the cooling mode based on the maximum and average temperatures collected from all cells in each battery pack; wherein the cooling mode includes multiple cooling modes, based on the maximum temperature collected from all cells in the battery pack. T max and average T mean The corresponding cooling mode is activated and switched within the specified range; the temperature control mode of the cooling unit is switched according to the temperature control mode of each battery pack in the battery cluster.

[0008] A second aspect of the present invention provides a cell-level intelligent temperature control method for a liquid-cooled energy storage device as described in the first aspect, for devices containing... n The battery clusters of each battery pack are collected. j Minimum temperature among all battery cells collected T j,min Maximum value T j,max and average T j,mean , j =1, 2, ... n Construct a combination of criteria for each battery pack j Temperature control mode switching includes: cooling mode and heating mode. The cooling mode includes multiple cooling levels. Each temperature control mode includes: start conditions, exit conditions, operation after start, and operation after exit. Among them, according to the battery pack j Minimum temperature among all battery cells collected T j,min and average T j,mean The battery pack j To activate or deactivate the heating mode; depending on the battery pack. j The maximum value among all cell temperature measurements T j,max and average T j,mean The battery packj To start or exit cooling mode; follow the battery pack instructions. j The maximum value among all cell temperature measurements T j,max and average T j,mean The range in which this battery pack belongs j Start and switch to the corresponding cooling mode.

[0009] Preferably, the heating mode includes: heating start conditions, heating stop conditions, heating operation, and standby mode after exiting; after the heating start conditions are met, the heating operation is executed until the heating stop conditions are met, then heating is stopped and standby mode after exiting is executed; The heating start condition is the battery pack. j Minimum temperature among all battery cells collected T j,min Below the minimum heating start value T sh,min And battery pack j Average temperature of all battery cells in the sample T j,mean Below average heating start value T sh,mean , The heating exit condition is the battery pack. j Minimum temperature among all battery cells collected T j,min Higher than the minimum heating exit value T qh,min And battery pack j Average temperature of all battery cells in the sample T j,mean Higher than average heating exit value T qh,mean Minimum heating start value T sh,min Less than the minimum heating exit value T qh,min and average heating start-up value T sh,mean Less than the average heating exit value T qh,mean .

[0010] Preferably, the heating operation includes: turning on the heating system and setting the water temperature. T h,in Inlet and outlet water temperature difference settings T h,delta .

[0011] Preferably, according to ( T sh,min , T sh,mean) = (16℃, 19℃), ( T qh,min , T qh,mean ) = (19℃, 23℃), ( T h,in , T h,delta = (21℃, 5℃) Sets the heating start conditions, heating stop conditions, and heating operation.

[0012] Preferably, the multiple cooling modes include: N There are several cooling levels, one for cooling and one for cooling. i File mode, i =1, 2, ... N ; Refrigeration i The modes include: Cooling i Start-up conditions, cooling i Exit conditions, cooling i High-speed and low-speed operation; meets cooling requirements. i Start-up conditions, perform cooling i Operate the settings until the cooling requirement is met. i Exit condition: Stop cooling i The gear operation will now downgrade to a lower gear, which means it will activate cooling. i -1 level operation, until it drops from cooling level 1 to standby.

[0013] Preferably, refrigeration i The starting condition is the battery pack. j The maximum value among all cell temperature measurements T j,max Higher than refrigeration i Maximum startup value T i,sc,max And battery pack j Average temperature of all battery cells in the sample T j,mean Higher than refrigeration i Average startup value T i,sc,mean , Refrigeration i The exit condition is the battery pack. j The maximum value among all cell temperature measurements T j,max Below the cooling i Maximum Exit Value T i,qc,max And battery pack j Average temperature of all battery cells in the sample T j,mean Below the cooling iAverage Exit Value T i,qc,mean , Refrigeration i Maximum startup value T i,sc,max Higher than refrigeration i Maximum Exit Value T i,qc,max Refrigeration i Maximum Exit Value T i,qc,max Higher than refrigeration i -1 gear maximum starting value T i-1,sc,max Refrigeration i Average startup value T i,sc,mean Higher than refrigeration i Average Exit Value T i,qc,mean Refrigeration i Average Exit Value T i,qc,mean Higher than refrigeration i -1 gear average starting value T i-1,sc,mean , For battery pack j To meet the cooling requirements i The starting conditions must meet the cooling requirements. i -1 starting condition, prioritizes cooling. i Speed ​​mode, until cooling is exited. i Speed ​​mode, enter cooling mode i -1 gear mode.

[0014] Preferably, the cooling mode consists of cooling level 1 and cooling level 2; according to( T 2,sc,max , T 2,sc,mean ) = (44℃, 41℃), ( T 2,qc,max , T 2,qc,mean ) = (39℃, 36℃), ( T 1,sc,max , T 1,sc,mean ) = (32℃, 29℃), ( T 1,qc,max , T 2,qc,mean ) = (28℃, 25℃), ( T 2,c,in , T 2,c,delta ) = (16℃, 3℃), (T 1,c,in , T 1,c,delta (25℃, 3℃) Sets the cooling start conditions, cooling stop conditions, and cooling operation.

[0015] Preferably, if there is a battery pack in the battery cluster that operates in heating mode, the temperature control mode of the liquid cooling unit is switched to heating mode, and the cooling unit provides the temperature. T h,in Warm water, inlet and outlet water temperature difference set T h,delta ; If any battery packs in the battery cluster are operating in cooling mode, the temperature control mode of the liquid cooling unit is determined by the highest cooling mode, and the cooling unit provides the required temperature. Tk , c , in Cooling water, inlet and outlet water set temperature difference T k,c,delta , k This is the serial number of the battery pack with the highest cooling level in the current battery cluster.

[0016] Preferably, the configuration includes an energy-saving mode and an efficiency mode, including: During periods of high electricity prices, the system enters energy-saving mode and collects the minimum temperature of all cells in all battery packs of the energy storage device. T all,min Maximum value T all,max and average T all,mean A combined criterion is constructed to switch the temperature control mode of the liquid cooling unit. The temperature control modes of the liquid cooling unit include: cooling mode and heating mode corresponding to the temperature control mode of each battery pack, wherein the cooling mode includes multiple cooling modes. During periods of low electricity prices, the criteria are simplified, and the system can directly enter the highest level of heating or cooling mode without saving on electricity costs, ensuring that the overall cell temperature operates at the optimal temperature and increasing system efficiency.

[0017] Compared with existing technologies, the beneficial effects of this invention include at least the following: The control strategy of this patent differs from previous control systems. By simply determining the highest or lowest temperature of the entire battery pack, the heating or cooling system can be directly activated, avoiding excessive consumption of cold and heat sources. Controlling the start and stop of the heating and cooling systems based on the cell temperature increases accuracy, effectively achieving precise temperature control of the battery pack and saving energy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a battery pack provided according to an embodiment of the present invention; Figure 2A flowchart of a cell control strategy provided according to an embodiment of the present invention; Figure 3 This is a system schematic diagram provided according to an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0020] like Figures 1 to 3 As shown, Embodiment 1 of the present invention provides a liquid-cooled energy storage device, comprising: a liquid-cooled unit and a battery cluster; wherein, the liquid-cooled unit includes: an evaporator, a compressor, a condenser, and an expansion valve, forming a refrigeration circuit; the battery cluster includes... n Each battery pack has an electronic flow switch installed on its liquid cooling branch. n The inlet of the liquid-cooled branch is connected to the output of the variable frequency infusion pump. n After the liquid outlets of the liquid-cooled branches converge, the liquid flows through the evaporator of the liquid-cooled unit and then re-enters the variable frequency liquid pump, forming a liquid-cooled circuit. Each liquid-cooled branch can operate independently in cooling mode, heating mode, or standby mode. Figure 3 As shown.

[0021] Based on the minimum temperature collected from all cells in the battery pack Tmin and average T mean The battery pack will activate or deactivate its heating mode based on the maximum temperature collected from all cells in the battery pack. T max and average T mean The battery pack can activate or deactivate cooling mode; the cooling mode includes multiple cooling levels, based on the maximum temperature collected from all cells in the battery pack. T max and average T mean The corresponding cooling mode is activated and switched within the specified range; the temperature control mode of the cooling unit is switched according to the temperature control mode of each battery pack in the battery cluster.

[0022] Preferred, but not limited, to NTC ( NegativeTemperatureCoefficientThermistor The negative temperature coefficient thermistor sensor collects the minimum temperature among all cells in each battery pack. Tmin Maximum value T maxand average T mean ,like Figure 1 As shown, NTC It is placed directly on the top surface of the battery cell to directly obtain the cell's temperature information.

[0023] like Figure 2 As shown, Embodiment 1 of the present invention provides a cell-level intelligent temperature control method for a liquid-cooled energy storage device as described in Embodiment 1, comprising the following steps: For battery pack j , j =1, 2, ... n Collect battery pack j Minimum temperature among all battery cells collected T j,min Maximum value T j,max and average T j,mean Construct a combination of criteria for each battery pack j Temperature control mode switching includes: cooling mode and heating mode. The cooling mode includes multiple cooling levels. Each temperature control mode includes: start conditions, exit conditions, operation after start, and operation after exit.

[0024] Among them, according to the battery pack j Minimum temperature among all battery cells collected T j,min and average T j,mean The battery pack j To activate or deactivate the heating mode; depending on the battery pack. j The maximum value among all cell temperature measurements T j,max and average T j,mean The battery pack j To start or exit cooling mode; follow the battery pack instructions. j The maximum value among all cell temperature measurements T j,max and average T j,mean The range in which this battery pack belongs j Start and switch to the corresponding cooling mode.

[0025] Specifically, the heating mode includes: heating start conditions, heating stop conditions, heating operation, and standby mode after exiting the heating mode. Once the heating start conditions are met, the heating operation is executed until the heating stop conditions are met, at which point heating stops and standby mode is executed after exiting the heating mode. This is based on the battery pack... j Minimum temperature among all battery cells collected Tj,min and battery pack j Average temperature of all battery cells in the sample T j,mean These values ​​are used as input values ​​for heating start-up and heating stop-down conditions.

[0026] The heating start condition is the battery pack. j Minimum temperature among all battery cells collected T j,min Below the minimum heating start value T sh,min And battery pack j Average temperature of all battery cells in the sample T j,mean Below average heating start value T sh,mean That is, it can be expressed by the following formula: T j,min < T sh,min & T j,mean < T sh,mean .

[0027] Preferably, but not limitingly, ( T sh,min , T sh,mean ) = (16℃, 19℃), meaning that when the battery pack j The minimum temperature of the battery cell was monitored to be less than 16℃, and the battery pack... j When the average temperature is less than 19°C, the system is deemed to need to activate the heating mode.

[0028] The heating exit condition is the battery pack. j Minimum temperature among all battery cells collected T j,min Higher than the minimum heating exit value T qh,min And battery pack j Average temperature of all battery cells in the sample T j,mean Higher than average heating exit value T qh,mean That is, it can be expressed by the following formula: Tmin > T qh,min & T mean > T qh,mean .

[0029] Preferably, but not limitingly, ( Tqh,min , T qh,mean ) = (19℃, 23℃), when the battery pack j The minimum temperature of the battery cell was detected to be higher than 19°C, and the battery pack... j When the average temperature exceeds 23°C, the system is deemed to need to exit heating mode.

[0030] It is worth noting that the minimum heating start value T sh,min Less than the minimum heating exit value T qh,min and average heating start-up value T sh,mean Less than the average heating exit value T qh,mean That is, it can be expressed by the following formula: T sh,min < T qh,min & T sh,mean < T qh,mean ...

[0031] Heating operations include: turning on the heating system and setting the water inlet temperature. T h,in Inlet and outlet water temperature difference settings T h,delta ; Further preferred, but not limiting, ( T h,in , T h,delta = (21℃, 5℃), which means that when the heating mode is activated, the liquid chiller provides water at 21℃, and the inlet and outlet water temperature difference is set to 5℃.

[0032] Specifically, the multiple cooling modes include: N There are several cooling levels, one for cooling and one for cooling. i File mode, i =1, 2, ... N ; Refrigeration i The modes include: Cooling i Start-up conditions, cooling i Exit conditions, cooling i Gear shifting and downshifting; sufficient cooling i Start-up conditions, perform cooling i Operate the settings until the cooling requirement is met. i Exit condition: Stop cooling i The gear operation will now downgrade to a lower gear, which means it will activate cooling. i-1 level operation, until it downgrades from cooling level 1 to standby. This includes the battery pack. j The maximum value among all cell temperature measurements T j,max and battery pack j Average temperature of all battery cells in the sample T j,mean As a refrigeration i Start-up conditions and cooling i The input value for the file exit condition.

[0033] Refrigeration i The starting condition is the battery pack. j The maximum value among all cell temperature measurements T j,max Higher than refrigeration i Maximum startup value T i,sc,max And battery pack j Average temperature of all battery cells in the sample T j,mean Higher than refrigeration i Average startup value T i,sc,mean That is, it can be expressed by the following formula: T j,max > T i,sc,max & T j,mean > Tj , i,sc,mean .

[0034] Refrigeration i The exit condition is the battery pack. j The maximum value among all cell temperature measurements T j,max Below the cooling i Maximum Exit Value T i,qc,max And battery pack j Average temperature of all battery cells in the sample T j,mean Below the cooling i Average Exit Value T i,qc,mean That is, it can be expressed by the following formula: T j,max < T i,qc,max & T j,mean < Tj i,qc,mean .

[0035] It is worth noting that refrigerationi Maximum startup value T i,sc,max Higher than refrigeration i Maximum Exit Value T i,qc,max Refrigeration i Maximum Exit Value T i,qc,max Higher than refrigeration i -1 gear maximum starting value T i-1,sc,max Refrigeration i Average startup value T i,sc,mean Higher than refrigeration i Average Exit Value T i,qc,mean Refrigeration i Average Exit Value T i,qc,mean Higher than refrigeration i -1 gear average starting value T i-1,sc,mean That is, it can be expressed by the following formula: T i,sc,max > T i,qc,max > T i-1,sc,max & T i,sc,mean > T i,qc,mean > T i-1,sc,mean .

[0036] Therefore, for the battery pack j To meet the cooling requirements i The starting conditions must meet the cooling requirements. i -1 level start conditions, but prioritizes cooling. i Cooling mode, rapid cooling, until cooling is stopped. i Speed ​​mode, enter cooling mode i -1 gear mode.

[0037] Refrigeration i The operation includes: turning on the cooling system, i Water inlet setting temperature Ti , c , in , i Temperature difference setting for inlet and outlet water Ti , c , delta ; i Water inlet setting temperature Ti , c , in Below i-1 setting for inlet water temperature Ti - 1,c,in Preferred but not limited, N = 2, meaning the cooling mode consists of cooling level 1 and cooling level 2.

[0038] Further, but not restrictively, the criterion is expressed by the following formula: ( T 2,sc,max , T 2,sc,mean ) = (44℃, 41℃), ( T 2,qc,max , T 2,qc,mean ) = (39℃, 36℃), ( T 1,sc,max , T 1,sc,mean ) = (32℃, 29℃), ( T 1,qc,max , T 2,qc,mean = (28℃, 25℃).

[0039] In other words, when the battery pack is detected j The maximum temperature of the battery cell is greater than 44℃, and the battery pack j When the average temperature exceeds 41℃, it is determined that the cooling mode 2 needs to be activated. When the maximum temperature of the battery cell is less than 39℃, and the battery pack... j When the average temperature is less than 36℃, exit the cooling mode 2 and enter the cooling mode 1; otherwise, continue to maintain the cooling mode 2. Further preferred, but not limiting, is the refrigeration operation expressed by the following formula: ( T 2,c,in , T 2,c,delta ) = (16℃, 3℃), ( T 1,c,in , T 1,c,delta = (25℃, 3℃).

[0040] In other words, when the cooling mode 2 is activated, the liquid chiller provides cooling water at 16°C, and the supply and return water temperature difference is set at 3°C. When the cooling mode 1 is activated, the liquid chiller provides cooling water at 25°C, and the supply and return water temperature difference is set at 3°C. The flow rate is adjusted by the variable frequency liquid pump. Understandably, the subscript in the temperature control mode h express heating heating, c express cooling cool down, s express start start up, q express quit , i Indicates gear position. min This represents the minimum value. max Indicates the maximum value. mean This represents the average value. delta Indicates temperature difference.

[0041] If the battery pack j Minimum temperature among all battery cells collected T j,min Maximum value T j,max and average T j,mean If the start-up conditions for each temperature control mode are not met, the liquid cooling unit enters standby mode and continuously collects data from each battery pack. j Minimum temperature among all battery cells collected T j,min Maximum value T j,max and average T j,mean Battery pack at any time j Switch to temperature control mode; If in the battery pack j The temperature control mode is standby mode, battery pack j The liquid cooling branch is equipped with an electronic flow switch that is in the off state, and the battery pack j It does not participate in the heat transfer of the liquid cooling unit; System-level control strategies include: collecting the minimum temperature of all cells across all battery packs in the energy storage device. T all,min Maximum value T all,max and average T all,mean A combined criterion is constructed to switch the temperature control mode of the liquid-cooled unit. The temperature control modes of the liquid-cooled unit include: cooling mode and heating mode corresponding to the temperature control mode of each battery pack, wherein the cooling mode includes multiple cooling modes.

[0042] In other words, if there is a battery pack in the battery cluster that operates in heating mode, the temperature control mode of the liquid cooling unit will switch to heating mode, and the cooling unit will provide the temperature. T h,in Warm water, inlet and outlet water temperature difference set T h,delta If any battery packs in the battery cluster are operating in cooling mode, the temperature control mode of the liquid cooling unit will be switched based on the highest cooling mode setting, and the cooling unit will provide the required temperature. Tk, c , in Cooling water, inlet and outlet water set temperature difference T k,c,delta , k This is the serial number of the battery pack with the highest cooling level in the current battery cluster.

[0043] When the battery pack temperature in the battery cluster is simultaneously at both cooling level 1 and cooling level 2, the chiller unit operates at cooling level 2, providing 16℃ cooling water, with the inlet and outlet water temperature difference set at 3℃.

[0044] By combining the start / stop status of the electronic flow switch of each battery pack and the mode status of the liquid cooling unit, the flow rate of the variable frequency infusion pump is adjusted. The main control parameter is the flow rate.

[0045] It is worth noting that in engineering practice, there is no situation where heating and cooling occur simultaneously. There may be situations where multiple cooling levels are met. In such cases, the highest level is used to ensure that the maximum temperature of all battery cells does not exceed the limit, which means the chiller is operated under the safest conditions.

[0046] Further, but not restrictively, the system-level control strategy includes configuring an energy-saving mode and an efficiency mode. During periods of high electricity prices, the system enters the energy-saving mode and collects the minimum temperature of all cells in all battery packs of the energy storage device. T all,min Maximum value T all,max and average T all,mean A combined criterion is constructed to switch the temperature control mode of the liquid cooling unit. The temperature control modes of the liquid cooling unit include: cooling mode and heating mode corresponding to the temperature control mode of each battery pack. The cooling mode includes multiple cooling modes. During periods of low electricity price, the criterion is simplified, and the unit directly enters the heating mode or the highest level of the cooling mode without saving electricity costs. This ensures that the overall cell temperature operates at the optimal temperature and increases system efficiency.

[0047] by NTC The temperature of each battery module is monitored in real time, and the liquid cooling system is adjusted based on the temperature data. This allows for continuous adjustment of the liquid cooling system's output, such as the liquid supply temperature and / or liquid supply flow rate, according to the heat load and its changing trends, thereby achieving rapid and precise control of the battery module temperature.

[0048] (1) By collecting the temperature of all cells in the battery pack and analyzing the data of the temperature of individual cells in the whole pack, the cooling system can be precisely controlled to avoid unnecessary waste of cold or heat sources.

[0049] (2) Flexible configuration function Users can customize the parameters and operating logic of the energy-saving mode according to the actual needs and operating strategies of the energy storage site. For example, users can set higher cooling or heating power during low electricity price periods and switch to energy-saving mode during high electricity price periods, based on local electricity pricing policies. The system also automatically activates natural cooling in low-temperature environments to reduce overall system energy consumption.

[0050] (3) Precise temperature management and intelligent temperature control at the cell level It supports real-time writing and dynamic analysis of cell temperature data. By adjusting multiple parameters such as refrigerant flow, water pump speed, and fan airflow, it ensures that the cell temperature difference is ≤2℃ (industry standard) to avoid localized overheating of the battery cluster. It provides multiple control modes such as flow priority and temperature difference priority, allowing manufacturers to quickly configure parameters for the liquid cooling system (precise flow control) and shorten the commissioning cycle.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A liquid-cooled energy storage device, comprising: Liquid cooling unit and battery cluster; characterized in that: Liquid cooling units include: evaporator, compressor, condenser and expansion valve, forming a refrigeration circuit; The battery cluster includes multiple battery packs. Each battery pack has an electronic flow switch installed on its liquid cooling branch. The liquid inlet of each liquid cooling branch is connected to the output of the variable frequency liquid pump. After the liquid outlets converge, the liquid flows through the evaporator of the liquid cooling unit and then back into the variable frequency liquid pump to form a liquid cooling circuit. Each liquid cooling branch can operate independently in cooling mode, heating mode or standby mode. The battery pack starts or stops heating mode based on the minimum and average temperatures collected from all cells in each battery pack, and starts or stops cooling mode based on the maximum and average temperatures collected from all cells in each battery pack. The cooling mode includes multiple cooling levels, based on the maximum temperature collected from all cells in the battery pack. T max and average T mean Start and switch to the corresponding cooling mode within the specified range; The temperature control mode of the cooling unit is switched according to the temperature control mode of each battery pack in the battery cluster.

2. A cell-level intelligent temperature control method for the liquid-cooled energy storage device according to claim 1, characterized in that, Includes the following steps: For including n The battery clusters of each battery pack are collected. j Minimum temperature among all battery cells collected T j,min Maximum value T j,max and average T j,mean , j =1, 2, ... n Construct a combination of criteria for each battery pack j Temperature control mode switching includes: cooling mode and heating mode. The cooling mode includes multiple cooling levels. Each temperature control mode includes: start conditions, exit conditions, operation after start, and operation after exit. Among them, according to the battery pack j Minimum temperature among all battery cells collected T j,min and average T j,mean The battery pack j To activate or deactivate the heating mode; depending on the battery pack. j The maximum value among all cell temperature measurements T j,max and average T j,mean The battery pack j To start or exit cooling mode; follow the battery pack instructions. j The maximum value among all cell temperature measurements T j,max and average T j,mean The range in which this battery pack belongs j Start and switch to the corresponding cooling mode.

3. The cell-level intelligent temperature control method for liquid-cooled energy storage devices according to claim 2, characterized in that: The heating mode includes: heating start condition, heating stop condition, heating operation, and standby after exiting; after the heating start condition is met, the heating operation is executed until the heating stop condition is met, then heating stops and standby after exiting is executed; The heating start condition is the battery pack. j Minimum temperature among all battery cells collected T j,min Below the minimum heating start value T sh,min And battery pack j Average temperature of all battery cells in the sample T j,mean Below average heating start value T sh,mean , The heating exit condition is the battery pack. j Minimum temperature among all battery cells collected T j,min Higher than the minimum heating exit value T qh,min And battery pack j Average temperature of all battery cells in the sample T j,mean Higher than average heating exit value T qh,mean , Minimum heating start value T sh,min Less than the minimum heating exit value T qh,min and average heating start-up value T sh,mean Less than the average heating exit value T qh,mean .

4. The cell-level intelligent temperature control method for liquid-cooled energy storage devices according to claim 3, characterized in that: Heating operations include: turning on the heating system and setting the water inlet temperature. T h,in Inlet and outlet water temperature difference settings T h,delta .

5. The cell-level intelligent temperature control method for liquid-cooled energy storage devices according to claim 4, characterized in that: according to( T sh,min , T sh,mean ) = (16℃, 19℃), ( T qh,min , T qh,mean ) = (19℃, 23℃), ( T h,in , T h,delta = (21℃, 5℃) Sets the heating start conditions, heating stop conditions, and heating operation.

6. A cell-level intelligent temperature control method for a liquid-cooled energy storage device according to any one of claims 2 to 5, characterized in that: Multiple cooling modes include: N There are several cooling levels, one for cooling and one for cooling. i File mode, i =1, 2, ... N ; Refrigeration i The modes include: Cooling i Start-up conditions, cooling i Exit conditions, cooling i High-speed and low-speed operation; meets cooling requirements. i Start-up conditions, perform cooling i Operate the settings until the cooling requirement is met. i Exit condition: Stop cooling i The gear operation will now downgrade to a lower gear, which means it will activate cooling. i -1 level operation, until it drops from cooling level 1 to standby.

7. The cell-level intelligent temperature control method for liquid-cooled energy storage devices according to claim 4, characterized in that: Refrigeration i The starting condition is the battery pack. j The maximum value among all cell temperature measurements T j,max Higher than refrigeration i Maximum startup value T i,sc,max And battery pack j Average temperature of all battery cells in the sample T j,mean Higher than refrigeration i Average startup value T i,sc,mean , Refrigeration i The exit condition is the battery pack. j The maximum value among all cell temperature measurements T j,max Below the cooling i Maximum Exit Value T i,qc,max And battery pack j Average temperature of all battery cells in the sample T j,mean Below the cooling i Average Exit Value T i,qc,mean , Refrigeration i Maximum startup value T i,sc,max Higher than refrigeration i Maximum Exit Value T i,qc,max Refrigeration i Maximum Exit Value T i,qc,max Higher than refrigeration i -1 gear maximum starting value T i-1,sc,max Refrigeration i Average startup value T i,sc,mean Higher than refrigeration i Average Exit Value T i,qc,mean Refrigeration i Average Exit Value T i,qc,mean Higher than refrigeration i -1 gear average starting value T i-1,sc,mean , For battery pack j To meet the cooling requirements i The starting conditions must meet the cooling requirements. i -1 starting condition, prioritizes cooling. i Speed ​​mode, until cooling is exited. i Speed ​​mode, enter cooling mode i -1 gear mode.

8. The cell-level intelligent temperature control method for a liquid-cooled energy storage device according to claim 7, characterized in that: The cooling mode consists of cooling level 1 and cooling level 2; according to( T 2,sc,max , T 2,sc,mean ) = (44℃, 41℃), ( T 2,qc,max , T 2,qc,mean ) = (39℃, 36℃), ( T 1,sc,max , T 1,sc,mean ) = (32℃, 29℃), ( T 1,qc,max , T 2,qc,mean ) = (28℃, 25℃), ( T 2,c,in , T 2,c,delta ) = (16℃, 3℃), ( T 1,c,in , T 1,c,delta (25℃, 3℃) Sets the cooling start conditions, cooling stop conditions, and cooling operation.

9. A cell-level intelligent temperature control method for a liquid-cooled energy storage device according to claim 8, characterized in that: If any battery pack in the battery cluster is operating in heating mode, the temperature control mode of the liquid cooling unit switches to heating mode, and the cooling unit provides the temperature. T h,in Warm water, inlet and outlet water temperature difference set T h,delta ; If any battery packs in the battery cluster are operating in cooling mode, the temperature control mode of the liquid cooling unit is determined by the highest cooling mode, and the cooling unit provides the required temperature. Tk , c , in Cooling water, inlet and outlet water set temperature difference T k,c,delta , k This is the serial number of the battery pack with the highest cooling level in the current battery cluster.

10. A cell-level intelligent temperature control method for a liquid-cooled energy storage device according to any one of claims 7 to 9, characterized in that: Configure energy-saving mode and efficiency mode, including: During periods of high electricity prices, the system enters energy-saving mode and collects the minimum temperature of all cells in all battery packs of the energy storage device. T all,min Maximum value T all,max and average T all,mean A combined criterion is constructed to switch the temperature control mode of the liquid cooling unit. The temperature control modes of the liquid cooling unit include: cooling mode and heating mode corresponding to the temperature control mode of each battery pack, wherein the cooling mode includes multiple cooling modes. During periods of low electricity prices, the criteria are simplified, and the system directly enters the highest setting of either heating or cooling mode.

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