Lithium battery linkage control system and method of immersed liquid cooling technology

Abstract

The invention discloses a lithium battery linkage control system and method based on an immersed liquid cooling technology, the working state of a lithium battery is judged by obtaining the operation parameters of the lithium battery, and when the lithium battery is in a floating charge state, linkage control of a circulating pump is achieved by obtaining the environment temperature of the battery. When the environment temperature of the battery is larger than or equal to a set threshold value, the circulating pump is started, and when the environment temperature of the battery is smaller than the set threshold value, the circulating pump enters a standby state. Linkage control over the circulating pump is achieved by monitoring the battery environment temperature, the temperature needed by lithium battery refrigeration is guaranteed, meanwhile, the circulating pump is prevented from being normally opened, waste of refrigeration energy is greatly reduced, and the purpose of reducing the operation cost of a data center is achieved. Besides, in consideration of heat dissipation hysteresis, when it is monitored that the temperature of the battery is smaller than a set threshold value, the air conditioner is logically required to continue to operate for a period of time and then enter a standby state, and therefore the influence of heat accumulation on the lithium battery is avoided.

Description

Technical Field

[0001] The present invention relates to the field of lithium battery heat dissipation and fire protection technology, and in particular to a lithium battery linkage control system and method involving immersion liquid cooling technology. Background Art

[0002] In the actual production and operation of lithium battery projects in data centers, there are problems such as lithium battery heat dissipation and lithium battery fire protection. At this time, a method that combines fire protection and battery heat dissipation is needed. The configuration of lithium batteries in data centers will hopefully reduce the infrastructure cost of data centers, improve the utilization rate of new energy in data centers, and ultimately reduce the energy consumption of data centers.

[0003] The temperature control technology solutions for lithium batteries in data centers are mainly divided into air cooling and liquid cooling. Air cooling is a cooling method that uses air as a medium. However, with the continuous increase in the scale and energy density of lithium battery cells, the shortcomings of air cooling systems in heat dissipation efficiency will gradually become apparent. The liquid cooling solution uses media such as water, ethylene glycol aqueous solution, and dielectric coolant. Through direct or direct contact with the battery, it has the characteristics of high heat dissipation efficiency due to the high volumetric specific heat capacity and thermal conductivity of the liquid, and is not affected by altitude factors. The liquid cooling system has a stronger heat dissipation capacity than the air cooling system, and is more adaptable to the large-scale and high-security development trend of data center projects.

[0004] However, the existing data center lithium battery temperature control technology solutions have the following problems:

[0005] 1. In order to ensure the required temperature for lithium battery cooling, the circulation pump is always on, which will cause waste of cooling energy and increase the operating costs of the data center;

[0006] 2. Failure to take into account the lag in heat dissipation will cause heat accumulation and affect the lithium battery. Summary of the invention

[0007] The purpose of the present invention is to solve the above existing technical problems and provide a lithium battery linkage control system and method using immersion liquid cooling technology, which can ensure the required temperature for lithium battery cooling while avoiding the constant operation of the circulation pump, thereby greatly reducing the waste of cooling energy and achieving the purpose of reducing the operating costs of the data center. The specific technical solution is as follows:

[0008] A lithium battery linkage control method using immersion liquid cooling technology comprises the following steps:

[0009] Step 1: Obtain lithium battery operating parameters through the battery parameter acquisition module;

[0010] Step 2: Determine the working state of the lithium battery according to the operating parameters of the lithium battery through the monitoring module; after obtaining the operating parameters of the lithium battery, the monitoring module obtains the working state of the lithium battery by comparing the current operating parameters with the discharge state parameters and floating charge state parameters set in the module; if it is in the floating charge state, execute step 3; if it is in the discharge state, execute step 5, and directly start the circulation pump until the discharge is completed, and then the circulation pump will continue to run for a certain period of time before entering the standby state.

[0011] Step 3: When the lithium battery is in a floating charge state, the ambient temperature of the battery is obtained through the ambient temperature acquisition module; a multi-point monitoring method is used to obtain the ambient temperature of the battery, especially to monitor the place where the heat of the battery is concentrated, and the highest temperature value is selected from multiple obtained ambient temperatures.

[0012] Step 4: Determine whether the ambient temperature of the battery is greater than or equal to a set threshold value through the monitoring module; if the ambient temperature of the battery is greater than or equal to the set threshold value, execute step 5; if the ambient temperature of the battery is less than the set threshold value, execute step 6;

[0013] Step 5: When the ambient temperature of the battery is greater than or equal to the set threshold, the circulation pump is turned on to enter heat exchange cooling;

[0014] Step 6: When the ambient temperature of the battery is lower than the set threshold, the circulation pump enters the standby state; when the coolant temperature inside the battery is lower than the set threshold, the circulation pump continues to run for 1 hour before entering the standby state.

[0015] Preferably, in step 1, the operating parameters of the lithium battery are obtained in two ways; the first is to use a lithium battery acquisition module to directly obtain the operating parameters on the lithium battery, and the operating parameters obtained at this time include the voltage, current and temperature of the lithium battery; the second way is to obtain the operating parameters of the lithium battery through an uninterruptible power supply UPS mode, that is, an uninterruptible power supply monitoring module, and the operating parameters obtained at this time include the battery bus voltage, battery bus current, built-in battery temperature, battery remaining backup time and percentage relative to the new battery capacity.

[0016] Preferably, if it is a floating charge state in step 2, the external power supply charges the lithium battery with a current of 0.1C, so as to maintain the lithium battery in a fully charged state. At this time, the current on the lithium battery and the current on the battery bus are close to 0 current, and the temperature of the built-in battery is close to 25°C; if it is a discharge state, the current on the lithium battery and the current on the battery bus are a discharge current of 4C to 6C, and the temperature rise of the built-in battery is within 30K.

[0017] A lithium battery linkage control system using immersion liquid cooling technology includes a battery parameter acquisition module, a monitoring module, an ambient temperature acquisition module, and a linkage control module. When the monitoring module determines that the battery temperature is greater than or equal to a set threshold, the monitoring module outputs an instruction to start a circulation pump to the linkage control module, and the linkage control module outputs a signal to a heat exchanger of the circulation pump to start the circulation pump; and when the monitoring module determines that the battery ambient temperature is less than the set threshold, the monitoring module outputs an instruction to the linkage control module to put the circulation pump into a standby state.

[0018] Preferably, when the battery temperature is lower than a set threshold or the battery discharge is complete, the monitoring module outputs a standby command after a delay of 30 minutes, and the air conditioner enters the standby state after running continuously for 1 hour.

[0019] Preferably, the monitoring module is directly connected to the circulation pump to directly control the working state of the circulation pump; the battery parameter acquisition module includes a lithium battery acquisition module and an uninterruptible power supply acquisition module, the lithium battery acquisition module is directly connected to the lithium battery to obtain the operating parameters of the lithium battery, and the uninterruptible power supply acquisition module directly obtains the operating parameters of the lithium battery through the uninterruptible power supply.

[0020] Preferably, the lithium battery acquisition module and the uninterruptible power supply acquisition module are respectively connected to the monitoring module via the MODBUS RTU protocol.

[0021] Preferably, the specific models of the lithium battery acquisition module, the uninterruptible power supply acquisition module, the monitoring module, the ambient temperature acquisition module, and the linkage control module are: MS-1, MS-2, MS-3, MS-4, and MS-5, respectively.

[0022] Compared with the closest prior art, the technical solution provided by the present invention has the following beneficial effects:

[0023] 1. The present invention discloses a lithium battery linkage control system and method for immersion liquid cooling technology. The operating state of the lithium battery is determined by obtaining the operating parameters of the lithium battery. When the lithium battery is in a floating charge state, the linkage control of the circulation pump is realized by obtaining the ambient temperature of the battery. When the ambient temperature of the battery is greater than or equal to a set threshold, the circulation pump is turned on, and when the ambient temperature of the battery is less than the set threshold, the circulation pump enters a standby state. The linkage control of the circulation pump is realized by monitoring the ambient temperature of the battery. While ensuring the temperature required for refrigeration of the lithium battery, the circulation pump is avoided from being constantly turned on, thereby greatly reducing the waste of refrigeration energy and achieving the purpose of reducing the operating costs of the data center.

[0024] 2. The present invention takes into account the hysteresis problem of heat dissipation. When the battery temperature is detected to be lower than a set threshold, the air conditioner is logically required to continue running for a period of time before entering the standby state, thereby avoiding the influence of heat accumulation on the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a lithium battery linkage control method of an immersion liquid cooling technology of the present invention;

[0026] Figure 2 This is a principle block diagram of a lithium battery linkage control system using an immersion liquid cooling technology of the present invention;

[0027] Among them: 1. Battery parameter acquisition module, 2. Monitoring module, 3. Ambient temperature acquisition module, 4. Linkage control module, 11. Lithium battery acquisition module, 12. Uninterruptible power supply acquisition module. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figure 1-2 .

[0030] Example 1

[0031] A lithium battery linkage control method using immersion liquid cooling technology comprises the following steps:

[0032] Step 1: Obtain the lithium battery operating parameters through the battery parameter acquisition module. The lithium battery acquisition module is used to directly obtain the operating parameters of the lithium battery. The operating parameters obtained at this time include the voltage, current and temperature of the lithium battery. During the discharge process of the lithium battery, the voltage and current of the lithium battery are both large, and the heat generated by the lithium battery is also large. Therefore, the working state of the lithium battery can be obtained by monitoring the voltage, current and temperature of the lithium battery. However, the present invention does not impose any limitation on the specific parameters obtained. In other embodiments, other parameters can be used to characterize the working state of the lithium battery.

[0033] Step 2: Determine the working state of the lithium battery according to the lithium battery operating parameters through the monitoring module; after obtaining the lithium battery operating parameters, the monitoring module obtains the working state of the lithium battery by comparing the current operating parameters with the discharge state parameters and floating charge state parameters set in the module; for example, in the floating charge state, the external power supply charges the lithium battery with a very small current to maintain the lithium battery in a fully charged state. At this time, the current on the lithium battery and the current on the battery bus are very small and the temperature of the built-in battery is also very low; and when the lithium battery is in a discharge state, the current on the lithium battery and the current on the battery bus are both very large and the temperature of the built-in battery is also very high. Therefore, after obtaining the operating parameters of the lithium battery, the monitoring module obtains the working state of the lithium battery by comparing the current operating parameters with the discharge state parameters and floating charge state parameters set in the module. When the lithium battery is in a floating charge state, execute step 3 to obtain the ambient temperature of the battery.

[0034] Step 3: When the lithium battery is in a floating charge state, the ambient temperature of the battery is obtained through the ambient temperature acquisition module; a multi-point monitoring method is used to obtain the ambient temperature of the battery, especially to monitor the places where the heat of the battery is concentrated, and the highest temperature value is selected from multiple obtained ambient temperatures. In this embodiment, a multi-point monitoring method is used to obtain the ambient temperature of the battery, especially to monitor the places where the heat of the battery is concentrated, and the highest temperature value is selected from multiple obtained ambient temperatures. However, the present invention does not impose any limitation on the processing method of multiple obtained ambient temperature values. In other embodiments, weighted averaging and other methods can be used to avoid erroneous monitoring caused by temperature sensor failure.

[0035] Step 4: Determine whether the ambient temperature of the battery is greater than or equal to a set threshold value through the monitoring module; if the ambient temperature of the battery is greater than or equal to the set threshold value, execute step 5; if the ambient temperature of the battery is less than the set threshold value, execute step 6;

[0036] Step 5: When the ambient temperature of the battery is greater than or equal to the set threshold, the circulation pump is turned on to enter heat exchange cooling;

[0037] Step 6: When the ambient temperature of the battery is lower than the set threshold, the circulation pump enters the standby state; when the coolant temperature inside the battery is lower than the set threshold, the circulation pump continues to run for 1 hour before entering the standby state.

[0038] Preferably, if it is a floating charge state in step 2, the external power supply charges the lithium battery with a very small current of 0.1C, so as to maintain the lithium battery in a fully charged state. At this time, the current on the lithium battery and the current on the battery bus are very small and close to 0 current, and the temperature of the built-in battery is also very low and close to 25°C; if it is a discharge state, the current on the lithium battery and the current on the battery bus are both very large, about 4C to 6C discharge current; and the temperature of the built-in battery is also very high, and the temperature rise is within 30K.

[0039] A lithium battery linkage control system using immersion liquid cooling technology includes a battery parameter acquisition module 1, a monitoring module 2, an ambient temperature acquisition module 3, and a linkage control module 4. The battery parameter acquisition module 1 is used to acquire the lithium battery operating parameters, and the monitoring module 2 is used to determine the lithium battery working state according to the lithium battery operating parameters; when the lithium battery is in a floating charge state, the ambient temperature acquisition module 3 acquires the battery ambient temperature; the monitoring module 2 is used to determine whether the battery ambient temperature is greater than or equal to a set threshold.

[0040] The specific working process of the linkage control module is as follows: when the temperature of the battery is less than the set threshold, the circulation pump enters the standby state. Specifically, when the monitoring module 2 determines that the temperature of the battery is greater than or equal to the set threshold, the monitoring module 2 outputs an instruction to start the circulation pump to the linkage control module 4, and the linkage control module 4 outputs a signal to the heat exchanger of the circulation pump to start the circulation pump. When the monitoring module 2 determines that the battery ambient temperature is less than the set threshold, the monitoring module 2 outputs an instruction to the linkage control module 4 to enter the standby state.

[0041] In other embodiments, the monitoring module 2 can be directly connected to the circulation pump to directly control the working state of the circulation pump. In this embodiment, the battery parameter acquisition module 1 includes a lithium battery acquisition module 11 and an uninterruptible power supply acquisition module 12. The lithium battery acquisition module 11 is directly connected to the lithium battery to obtain the operating parameters of the lithium battery, and the uninterruptible power supply acquisition module 12 obtains the operating parameters of the lithium battery through the uninterruptible power supply.

[0042] Furthermore, the lithium battery acquisition module 11 and the uninterruptible power supply acquisition module 12 are respectively connected to the monitoring module via the MODBUS RTU protocol.

[0043] Furthermore, since heat dissipation has a certain hysteresis, when the battery temperature is lower than the set threshold or the battery discharge is completed, the monitoring module 2 outputs a standby command after a delay of 30 minutes, and the air conditioner enters the standby state after running continuously for 1 hour.

[0044] Example 2

[0045] A lithium battery linkage control method using immersion liquid cooling technology comprises the following steps:

[0046] Step 1: Obtain the lithium battery operating parameters through the battery parameter acquisition module, and obtain the lithium battery operating parameters through the uninterruptible power supply UPS mode, that is, the uninterruptible power supply monitoring module. The operating parameters obtained at this time include battery bus voltage, battery bus current, built-in battery temperature, remaining battery backup time, and percentage relative to the new battery capacity. Under normal operating conditions of the data center, the UPS host (uninterruptible power supply host) and input and output cabinets and other equipment in the data center are powered by external power supplies. The lithium battery is in a standby state. The external power supply floats the lithium battery with a small current to keep the lithium battery fully charged. At this time, the heat emitted by the lithium battery is very slight; and the ambient temperature inside the battery is less affected by external interference. At this time, the battery is immersed in the coolant. The cooling capacity required for internal heat dissipation is very small, and the circulation pump does not need to be always on.

[0047] Step 2: Determine the working state of the lithium battery according to the operating parameters of the lithium battery through the monitoring module; after obtaining the operating parameters of the lithium battery, the monitoring module obtains the working state of the lithium battery by comparing the current operating parameters with the discharge state parameters and floating charge state parameters set in the module; if it is in the floating charge state, execute step 3; if it is in the discharge state, execute step 5, and directly start the circulation pump until the discharge is completed, and then the circulation pump will continue to run for a certain period of time before entering the standby state.

[0048] Step 3: When the lithium battery is in a floating charge state, the ambient temperature of the battery is obtained through the ambient temperature acquisition module; a multi-point monitoring method is used to obtain the ambient temperature of the battery, especially to monitor the place where the heat of the battery is concentrated, and the highest temperature value is selected from multiple obtained ambient temperatures.

[0049] Step 4: Determine whether the ambient temperature of the battery is greater than or equal to a set threshold value through the monitoring module; if the ambient temperature of the battery is greater than or equal to the set threshold value, execute step 5; if the ambient temperature of the battery is less than the set threshold value, execute step 6;

[0050] Step 5: When the ambient temperature of the battery is greater than or equal to the set threshold, the circulation pump is turned on to enter heat exchange cooling;

[0051] Step 6: When the ambient temperature of the battery is lower than the set threshold, the circulation pump enters the standby state; when the coolant temperature inside the battery is lower than the set threshold, the circulation pump continues to run for 1 hour before entering the standby state.

[0052] In summary, the present invention provides a lithium battery linkage control system and method of immersion liquid cooling technology, which determines the working state of the lithium battery by obtaining the operating parameters of the lithium battery, and realizes linkage control of the circulation pump by obtaining the ambient temperature of the battery when the lithium battery is in a floating charge state. The circulation pump is turned on when the ambient temperature of the battery is greater than or equal to the set threshold, and the circulation pump enters a standby state when the ambient temperature of the battery is less than the set threshold. The linkage control of the circulation pump is realized by monitoring the ambient temperature of the battery, and the circulation pump is avoided from being always on while ensuring the temperature required for lithium battery cooling, thereby greatly reducing the waste of cooling energy and achieving the purpose of reducing the operating costs of the data center. In addition, considering the hysteresis of heat dissipation, when it is monitored that the temperature of the battery is less than the set threshold, it is logically required that the air conditioner continue to run for a period of time before entering the standby state, so as to avoid the influence of heat accumulation on the lithium battery.

[0053] In addition, it is particularly noted that when the lithium battery of the present invention is normally charged and discharged, heat is released, and the heat is transferred from the battery to the liquid. A circulating pump is used to transport the heated coolant to an external heat exchanger, where it is cooled and circulated back to the battery, so that the battery is always kept at a suitable temperature. The lithium battery of the present invention is immersed in the coolant, and 100% of the outer surface of the battery can be used for heat dissipation, so that the heat of the battery is transferred in all directions. At the same time, there is no thermal interface material to reduce the contact thermal resistance. Both of the above factors can reduce the maximum temperature of the battery and ensure the consistency of the battery temperature. Typical substances of the coolant include fluorocarbon compounds (fluorinated liquid) as coolants for immersion single-phase liquid cooling technology. The specific physical properties of the coolant are as follows:

[0054] Table 1 Coolant physical parameters

[0055] Physical properties Fluoride liquid Thermal conductivity 0.0623W / (m·℃) Specific heat 1 014J / (kg·℃) Density(25℃) 1 830kg / m Volume expansion coefficient (1 / K) 0.0014 Kinematic viscosity (25℃) <![CDATA[1.3mm 2 / s]]>

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art can still modify or make equivalent substitutions to the specific implementations of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A lithium battery linkage control method using immersion liquid cooling technology, characterized in that: The following steps are involved: Step 1: Obtain lithium battery operating parameters through the battery parameter acquisition module; Step 2: The monitoring module determines the working state of the lithium battery according to the operating parameters of the lithium battery; after obtaining the operating parameters of the lithium battery, the monitoring module obtains the working state of the lithium battery by comparing the current operating parameters with the discharge state parameters and the floating charge state parameters set in the module; if it is in the floating charge state, step 3 is executed; if it is in the discharge state, step 5 is executed, and the circulation pump is directly turned on until the discharge is completed, and then the circulation pump continues to run for a certain period of time before entering the standby state; Step 3: When the lithium battery is in a floating charge state, the ambient temperature of the battery is obtained through the ambient temperature acquisition module; a multi-point monitoring method is used to obtain the ambient temperature of the battery, especially to monitor the place where the heat of the battery is concentrated, and the highest temperature value is selected from multiple obtained ambient temperatures; Step 4: Determine whether the ambient temperature of the battery is greater than or equal to a set threshold value through the monitoring module; if the ambient temperature of the battery is greater than or equal to the set threshold value, execute step 5; if the ambient temperature of the battery is less than the set threshold value, execute step 6; Step 5: When the ambient temperature of the battery is greater than or equal to the set threshold, the circulation pump is turned on to enter heat exchange cooling; Step 6: When the ambient temperature of the battery is lower than the set threshold, the circulation pump enters the standby state; when the coolant temperature inside the battery is lower than the set threshold, the circulation pump continues to run for 1 hour before entering the standby state.

2. The lithium battery linkage control method of immersion liquid cooling technology according to claim 1 is characterized in that: In step 1, the operating parameters of the lithium battery are obtained in two ways; the first is to use a lithium battery acquisition module to directly obtain the operating parameters on the lithium battery, and the operating parameters obtained at this time include the voltage, current and temperature of the lithium battery; the second way is to obtain the operating parameters of the lithium battery through an uninterruptible power supply UPS mode, that is, an uninterruptible power supply monitoring module, and the operating parameters obtained at this time include the battery bus voltage, battery bus current, built-in battery temperature, battery remaining backup time and percentage relative to the new battery capacity.

3. The lithium battery linkage control method of immersion liquid cooling technology according to claim 1 is characterized in that: If the step 2 is in a floating charge state, the external power supply charges the lithium battery with a current of 0.1C to maintain the lithium battery in a fully charged state. At this time, the current on the lithium battery and the current on the battery bus are close to 0 current, and the temperature of the built-in battery is close to 25°C; if it is in a discharge state, the current on the lithium battery and the current on the battery bus are a discharge current of 4C to 6C, and the temperature rise of the built-in battery is within 30K.

4. A lithium battery linkage control system using immersion liquid cooling technology, comprising a battery parameter acquisition module, a monitoring module, an ambient temperature acquisition module, and a linkage control module, characterized in that: When the monitoring module determines that the battery temperature is greater than or equal to the set threshold, the monitoring module outputs an instruction to start the circulation pump to the linkage control module, and the linkage control module outputs a signal to the heat exchanger of the circulation pump to start the circulation pump; and when the monitoring module determines that the battery ambient temperature is less than the set threshold, the monitoring module outputs an instruction to the linkage control module to enter the standby state of the circulation pump.

5. The lithium battery linkage control system of the immersion liquid cooling technology according to claim 4 is characterized in that: When the battery temperature is lower than the set threshold or the battery discharge is complete, the monitoring module outputs a standby command after a delay of 30 minutes, and the air conditioner enters the standby state after running continuously for 1 hour.

6. The lithium battery linkage control system of the immersion liquid cooling technology according to claim 4 is characterized in that: The monitoring module is directly connected to the circulation pump to directly control the working state of the circulation pump; the battery parameter acquisition module includes a lithium battery acquisition module and an uninterruptible power supply acquisition module, the lithium battery acquisition module is directly connected to the lithium battery to obtain the operating parameters of the lithium battery, and the uninterruptible power supply acquisition module directly obtains the operating parameters of the lithium battery through the uninterruptible power supply.

7. The lithium battery linkage control system of the immersion liquid cooling technology according to claim 6 is characterized in that: The lithium battery acquisition module and the uninterruptible power supply acquisition module are respectively connected to the monitoring module via the MODBUS RTU protocol.

8. The lithium battery linkage control system of the immersion liquid cooling technology according to claim 7 is characterized in that: The specific models of the lithium battery acquisition module, uninterruptible power supply acquisition module, monitoring module, ambient temperature acquisition module, and linkage control module are: MS-1, MS-2, MS-3, MS-4, and MS-5.

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