Immersed refrigerant direct cooling energy storage temperature control system and control method thereof

Abstract

The invention relates to an immersed refrigerant direct-cooling energy storage temperature control system, which comprises an energy storage cabinet, a compressor, a condenser, a liquid storage tank, an electronic expansion valve and a gas-liquid separator, a plurality of groups of battery packs connected in parallel are arranged in the energy storage cabinet, battery cells are arranged in the battery packs, each battery pack is connected in series with a group of quick release stop valves, the quick release stop valves are respectively connected to two ends of the battery pack, and the compressor is connected with the condenser. The interior of the battery pack is integrally filled with insulating liquid, the condenser is communicated with the compressor, the compressor is communicated with the gas-liquid separator, the gas-liquid separator is connected with the battery pack, the other end of the condenser is communicated with the liquid storage tank, the liquid storage tank is connected with the electronic expansion valve, and the other end of the electronic expansion valve is connected with the other end of the battery pack. The temperature control system disclosed by the invention can effectively cool the lithium battery meeting high-rate charge and discharge, improve the temperature consistency of each battery cell, reduce the temperature gradient in the battery pack, reduce the use amount of cooling liquid, reduce the intermediate heat exchange link by adopting refrigerant direct cooling, improve the energy efficiency of a temperature control unit and reduce the operation power consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to an immersion refrigerant direct cooling energy storage temperature control system and a control method thereof. Background Art

[0002] Renewable energy generation is gradually accounting for a larger and larger proportion of social electricity, but renewable energy sources such as photovoltaics and wind power vary greatly with the seasons and weather conditions. The introduction of energy storage technology can improve and compensate for wind and photovoltaic power generation, ensuring that the power generation is equal to the power load.

[0003] In electric energy storage, in addition to traditional pumped storage, there are also new energy storage. Among the new energy storage, lithium-ion batteries occupy a dominant position. Several lithium batteries are connected in series and parallel and placed in a container to form an energy storage container to achieve energy storage or release. However, lithium batteries have strict requirements on working temperature, and the general temperature needs to be stable at 15 to 35°C. This requires the establishment of an energy storage temperature control system to adjust the environment of the lithium batteries in the energy storage container so that they can work in an ideal environment.

[0004] There are two current temperature control methods for lithium-ion batteries: air cooling and liquid cooling. Air cooling accounts for the highest proportion, and the penetration rate of liquid cooling is rising rapidly. However, conventional liquid cooling methods are divided into indirect cold plate liquid cooling and full immersion liquid cooling that directly contacts the battery cell. Since the contact surface of cold plate liquid cooling is limited to one surface, there will be a large temperature gradient problem between the upper and lower parts of the battery cell. The cold plate uses water + 50% ethylene glycol solution, and leakage from the bottom cold plate poses a great safety risk. The conventional direct full immersion liquid cooling solution, although it solves the safety problems caused by temperature gradient and leakage, has a large demand for cooling medium in direct full immersion, and the viscosity of the cooling medium is generally large, resulting in high energy consumption of the circulating pump. Summary of the invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide an immersion refrigerant direct cooling energy storage temperature control system, which can not only effectively cool the lithium battery under high-rate charge and discharge, improve the temperature consistency of each battery cell, and reduce the temperature gradient inside the battery pack, but also reduce the use of coolant and reduce initial costs. The use of refrigerant direct cooling reduces the intermediate heat exchange link, improves the energy efficiency of the temperature control unit, and reduces operating power consumption.

[0006] The objective of the present invention is achieved through the following technical solutions: an immersion refrigerant direct cooling energy storage temperature control system, comprising an energy storage cabinet, a compressor, a condenser, a liquid storage tank, an electronic expansion valve and a gas-liquid separator, wherein the energy storage cabinet is provided with a plurality of parallel battery packs, the battery packs are provided with battery cells, each battery pack is connected in series with a group of quick-release stop valves, the quick-release stop valves are respectively connected to the two ends of the battery pack, the interior of the battery pack is filled with insulating liquid as a whole, one end of the condenser is connected to the compressor, the compressor is connected to the gas-liquid separator, the gas-liquid separator is connected to one end of the battery pack, the other end of the condenser is connected to the liquid storage tank, the liquid storage tank is connected to one end of the electronic expansion valve, and the other end of the electronic expansion valve is connected to the quick-release stop valve.

[0007] The temperature control system in the present invention can control the overall temperature of the battery cells and achieve the uniform temperature requirement between the battery cells. At the same time, the immersion liquid prevents thermal runaway of the battery cells, improves the overall energy efficiency of the temperature control system, and optimizes the initial cost of the temperature control system. Furthermore, the temperature control system can not only effectively cool the lithium batteries that meet high-rate charge and discharge conditions, improve the temperature consistency of each battery cell, and reduce the temperature gradient inside the battery pack, but also reduce the use of coolant and reduce the initial cost. The use of direct cooling with refrigerant reduces the intermediate heat exchange link, improves the energy efficiency of the temperature control unit, and reduces the operating power consumption. The electronic expansion valve can be used to adjust the refrigerant flow rate. At the same time, each battery pack inlet and outlet is provided with a quick-release stop valve to facilitate the maintenance of a single fault pack.

[0008] Preferably, the energy storage cabinet is further provided with a plurality of evaporators, and the evaporators are integrated with the battery pack; the battery pack adopts a heat exchange pipeline surrounding the battery.

[0009] Preferably, the battery pack adopts a bottom refrigerant direct cooling plate method.

[0010] Preferably, a direct cooling pipeline is provided in the battery pack, and the direct cooling pipeline is arranged on the top of the battery cell and around the battery cell; the direct cooling pipeline is a copper tube, an aluminum tube, a copper tube bracket or an aluminum tube bracket.

[0011] The present invention allows the refrigerant to directly enter the battery pack, which reduces the heat exchange link of the intermediate plate heat exchanger and reduces the overall energy consumption of the temperature control system. It ensures the uniform temperature effect of the entire battery cell by statically filling the immersion insulating liquid and isolates oxygen to eliminate the risk of fire.

[0012] Preferably, a short tube connecting end and a long tube connecting end are provided in the gas-liquid separator, the short tube connecting end is connected to the compressor, and the long tube connecting end is connected to one end of the battery pack.

[0013] Preferably, an intake pressure sensor and a low pressure switch are provided between the compressor and the gas-liquid separator, the intake pressure sensor is located on a side close to the compressor, and the low pressure switch is located on a side close to the gas-liquid separator.

[0014] Preferably, a high-pressure switch and an exhaust temperature sensor are provided between the compressor and the condenser, the exhaust temperature sensor is located on a side close to the compressor, and the high-pressure switch is located on a side close to the condenser.

[0015] Preferably, a pre-valve pressure sensor, a pre-valve temperature sensor, a filter and a sight glass are sequentially provided between the liquid storage tank and the electronic expansion valve along the material flow direction, and the exhaust temperature sensor is electrically connected to a controller provided in the system.

[0016] The present invention also provides a control method for an immersion refrigerant direct cooling energy storage temperature control system, comprising the following steps:

[0017] S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command;

[0018] S2, the controller receives the power on / off command from the host computer;

[0019] S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and starts according to the start-up sequence; otherwise, the unit is kept in the off state;

[0020] S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor;

[0021] S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7;

[0022] S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

[0023] Preferably, when starting and shutting down the temperature control system, a shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor needs to be executed.

[0024] Preferably, the insulating liquid comprises the following raw materials in percentages: 80-95% base oil, 0.1-5% antioxidant, 0.1-5% corrosion inhibitor, 0.1-5% inhibitor, and 0.5-1.5% flame retardant.

[0025] Preferably, the base oil is one or more of API-II, API-III, and API-V base oils; the API-III base oil has a carbon number of 10-60 and a kinematic viscosity of 1.0-8.0 mm2·s-1 at 100°C;

[0026] Preferably, the API-III base oil is ULTRA-S series base oil, Yubase series base oil, ADbase series base oil, Nexbase series base oil, ICCSYN series base oil, or SINOPURE series base oil.

[0027] The base oil used in the present invention has good compatibility with the materials and equipment currently in use, and the fluid can be replaced for use without replacing the materials and equipment.

[0028] Preferably, the antioxidant is at least one of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol) and 2,6-di-tert-butyl-α-dimethylamino-p-cresol.

[0029] Preferably, the corrosion inhibitor is one or more of sodium silicate, sebacic acid, isooctanoic acid, toluene triazole, benzotriazole, sodium phosphate and sodium petroleum sulfonate.

[0030] Preferably, the inhibitor is at least one of a benzotriazole derivative and a methylbenzotriazole derivative.

[0031] Preferably, the flame retardant is at least one of tetrachloroethylene, triisopropylphenyl phosphate, tri(xylene) phosphate, hexachloropropylene, and hexachlorobutadiene.

[0032] The insulating cooling oil in the present invention has good insulation and flame retardancy, and has good compatibility with insulating cooling oil. While improving the flame retardancy of insulating cooling oil, the physical and chemical properties of insulating cooling oil are further optimized and improved. It can effectively inhibit the occurrence of battery thermal runaway and reduce the harm caused by battery thermal runaway; the 2,6-di-tert-butyl-p-cresol used can effectively reduce the viscosity of insulating cooling oil and improve its fluidity, thereby improving the heat transfer and thermal conductivity of the insulating liquid.

[0033] The beneficial effects of the present invention are as follows: the temperature control system of the present invention can reduce the intermediate heat exchange link of the plate heat exchanger by directly passing the refrigerant through the cold plate of the temperature control unit, thereby improving the heat exchange efficiency. At the same time, the temperature gradient problem between the battery cells is reduced by filling the insulating liquid inside the battery pack; the use of the refrigerant direct cooling plate solution can reduce the circulation pump components and plate heat exchanger components of the previous temperature control unit, thereby improving the overall heat exchange efficiency while reducing the temperature gradient and reducing the overall cost of the temperature control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of the structure of the system in Example 1;

[0035] Figure 2 This is a schematic diagram of the structure of the battery pack in Example 1 using a bottom refrigerant direct cooling plate;

[0036] Figure 3 is a schematic diagram of the structure of the system in Example 2;

[0037] Figure 4 is a schematic diagram of the structure of a direct cooling pipeline provided in the battery pack in Example 2;

[0038] Figure 5 This is a schematic diagram of the structure of the battery pack in Example 5 using a surrounding copper tube;

[0039] Figure 6 It is a schematic diagram of the operation flow of the temperature control system in the present invention;

[0040] Figure 7 It is a timing diagram H1H2 of the central control system of the present invention.

[0041] The accompanying drawings are marked as follows: 1-energy storage cabinet, 111-battery pack, 112-battery cell, 113-quick release stop valve, 114-insulating liquid, 115-direct cooling pipeline, 2-compressor, 3-condenser, 4-liquid storage tank, 5-electronic expansion valve, 6-gas-liquid separator, 7-intake pressure sensor, 8-low pressure switch, 9-high pressure switch, 10-exhaust temperature sensor, 11-valve front pressure sensor, 12-valve front temperature sensor, 13-filter and 14-sight glass. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of those skilled in the art, the following embodiments and attached Figure 1-7 The present invention is further described, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0043] Example 1

[0044] See Figure 1-2, an immersion refrigerant direct cooling energy storage temperature control system, comprising an energy storage cabinet 1, a compressor 2, a condenser 3, a liquid storage tank 4, an electronic expansion valve 5 and a gas-liquid separator 6, wherein the energy storage cabinet 1 is provided with a plurality of parallel battery packs 111, wherein the battery pack 111 is provided with a battery cell 112, wherein each battery pack 111 is connected in series with a group of quick-release stop valves 113, wherein the quick-release stop valves 113 are respectively connected to the two ends of the battery pack 111, wherein the interior of the battery pack 111 is filled with an insulating liquid 114 as a whole, wherein one end of the condenser 3 is communicated with the compressor 2, wherein the compressor 2 is communicated with the gas-liquid separator 6, wherein the gas-liquid separator 6 is connected to one end of the battery pack 111, wherein the other end of the condenser 3 is communicated with the liquid storage tank 4, wherein the liquid storage tank 4 is connected to one end of the electronic expansion valve 5, wherein the other end of the electronic expansion valve 5 is connected to the quick-release stop valve 113.

[0045] The energy storage cabinet 1 is further provided with a plurality of evaporators, which are integrated with the battery pack 111 ; the battery pack 111 adopts a heat exchange pipeline that surrounds the battery.

[0046] like Figure 2 The battery pack 111 shown adopts a bottom refrigerant direct cooling plate method.

[0047] The gas-liquid separator 6 is provided with a short tube connection end and a long tube connection end. The short tube connection end is communicated with the compressor 2 , and the long tube connection end is connected to one end of the battery pack 111 .

[0048] An intake pressure sensor 7 and a low pressure switch 8 are provided between the compressor 2 and the gas-liquid separator 6 . The intake pressure sensor 7 is located on a side close to the compressor 2 , and the low pressure switch 8 is located on a side close to the gas-liquid separator 6 .

[0049] A high-pressure switch 9 and an exhaust temperature sensor 10 are provided between the compressor 2 and the condenser 3 . The exhaust temperature sensor 10 is located on a side close to the compressor 2 , and the high-pressure switch 9 is located on a side close to the condenser 3 .

[0050] A pre-valve pressure sensor 11, a pre-valve temperature sensor 12, a filter 13 and a sight glass 14 are sequentially arranged between the liquid storage tank 4 and the electronic expansion valve 5 along the material flow direction, and the exhaust temperature sensor 10 is electrically connected to a controller arranged in the system.

[0051] A control method for an immersion refrigerant direct cooling energy storage temperature control system comprises the following steps:

[0052] S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command;

[0053] S2, the controller receives the power on / off command from the host computer;

[0054] S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and starts according to the start-up sequence; otherwise, the unit is kept in the off state;

[0055] S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor;

[0056] S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7;

[0057] S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

[0058] When starting and shutting down the temperature control system, the shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor must be executed.

[0059] During the dehumidification process in step S2, the evaporator is started, the low-pressure switch 8 is turned on, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the exhaust port of the compressor 2, the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0060] In the liquid cooling heat dissipation process of step S4, the low-pressure switch 8 is turned on, the high-pressure switch 9 is turned off, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, the gas-liquid separator 6, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0061] In the evaporator heating of step S6 and step S7, the electronic expansion valve 5 and the high-pressure switch 9 are closed, the low-pressure switch 8 is opened, and the evaporator, the gas-liquid separator 6 and the compressor 2 are all working.

[0062] The insulating liquid comprises raw materials in the following percentages: 85% of base oil, 5% of antioxidant, 5% of corrosion inhibitor, 3.5% of inhibitor and 1.5% of flame retardant.

[0063] The base oil is API-II; the carbon number of the API-III base oil is 10-60, and the kinematic viscosity at 100°C is 1.0-8.0 mm2·s-1.

[0064] The antioxidant is 2,6-di-tert-butyl-p-cresol.

[0065] The corrosion inhibitor is sodium silicate.

[0066] The inhibitor is a benzotriazole derivative.

[0067] The flame retardant is tetrachloroethylene.

[0068] Example 2

[0069] See Figure 3-4 , an immersion refrigerant direct cooling energy storage temperature control system, comprising an energy storage cabinet 1, a compressor 2, a condenser 3, a liquid storage tank 4, an electronic expansion valve 5 and a gas-liquid separator 6, wherein the energy storage cabinet 1 is provided with a plurality of parallel battery packs 111, wherein the battery pack 111 is provided with a battery cell 112, wherein each battery pack 111 is connected in series with a group of quick-release stop valves 113, wherein the quick-release stop valves 113 are respectively connected to the two ends of the battery pack 111, wherein the interior of the battery pack 111 is filled with an insulating liquid 114 as a whole, wherein one end of the condenser 3 is communicated with the compressor 2, wherein the compressor 2 is communicated with the gas-liquid separator 6, wherein the gas-liquid separator 6 is connected to one end of the battery pack 111, wherein the other end of the condenser 3 is communicated with the liquid storage tank 4, wherein the liquid storage tank 4 is connected to one end of the electronic expansion valve 5, wherein the other end of the electronic expansion valve 5 is connected to the quick-release stop valve 113.

[0070] The energy storage cabinet 1 is further provided with a plurality of evaporators, which are integrated with the battery pack 111 ; the battery pack 111 adopts a heat exchange pipeline that surrounds the battery.

[0071] like Figure 4 As shown, a direct cooling pipeline 115 is provided in the battery pack 111 , and the direct cooling pipeline 115 is arranged on the top of the battery cell 112 and around the battery cell 112 ; the direct cooling pipeline is a copper tube, an aluminum tube, a copper tube bracket or an aluminum tube bracket.

[0072] The gas-liquid separator 6 is provided with a short tube connection end and a long tube connection end. The short tube connection end is communicated with the compressor 2 , and the long tube connection end is connected to one end of the battery pack 111 .

[0073] An intake pressure sensor 7 and a low pressure switch 8 are provided between the compressor 2 and the gas-liquid separator 6 . The intake pressure sensor 7 is located on a side close to the compressor 2 , and the low pressure switch 8 is located on a side close to the gas-liquid separator 6 .

[0074] A high-pressure switch 9 and an exhaust temperature sensor 10 are provided between the compressor 2 and the condenser 3 . The exhaust temperature sensor 10 is located on a side close to the compressor 2 , and the high-pressure switch 9 is located on a side close to the condenser 3 .

[0075] A pre-valve pressure sensor 11, a pre-valve temperature sensor 12, a filter 13 and a sight glass 14 are sequentially arranged between the liquid storage tank 4 and the electronic expansion valve 5 along the material flow direction, and the exhaust temperature sensor 10 is electrically connected to a controller arranged in the system.

[0076] A control method for an immersion refrigerant direct cooling energy storage temperature control system comprises the following steps:

[0077] S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command;

[0078] S2, the controller receives the power on / off command from the host computer;

[0079] S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and starts according to the start-up sequence; otherwise, the unit is kept in the off state;

[0080] S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor;

[0081] S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7;

[0082] S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

[0083] When starting and shutting down the temperature control system, the shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor must be executed.

[0084] During the dehumidification process in step S2, the evaporator is started, the low-pressure switch 8 is turned on, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the exhaust port of the compressor 2, the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0085] In the liquid cooling heat dissipation process of step S4, the low-pressure switch 8 is turned on, the high-pressure switch 9 is turned off, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, the gas-liquid separator 6, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0086] In the evaporator heating of step S6 and step S7, the electronic expansion valve 5 and the high-pressure switch 9 are closed, the low-pressure switch 8 is opened, and the evaporator, the gas-liquid separator 6 and the compressor 2 are all working.

[0087] The insulating liquid comprises raw materials in the following percentages: 95% of base oil, 0.1% of antioxidant, 0.1% of corrosion inhibitor, 4.3% of inhibitor, and 0.5% of flame retardant.

[0088] The base oil is API-III; the carbon number of the API-III base oil is 10-60, and the kinematic viscosity at 100°C is 1.0-8.0 mm2·s-1; the API-III base oil is ULTRA-S series base oil.

[0089] The antioxidant is composed of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol and 4,4'-methylenebis(2,6-di-tert-butylphenol) in a mass ratio of 0.8:0.7:0.5.

[0090] The corrosion inhibitor is composed of sodium silicate, isooctanoic acid and toluene triazole in a mass ratio of 0.8:0.7:0.7.

[0091] The inhibitor is a methylbenzotriazole derivative.

[0092] The flame retardant is composed of tetrachloroethylene, triisopropylphenyl phosphate and hexachlorobutadiene in a mass ratio of 0.8:0.7:0.9.

[0093] Example 3

[0094] See Figure 3-4, an immersion refrigerant direct cooling energy storage temperature control system, comprising an energy storage cabinet 1, a compressor 2, a condenser 3, a liquid storage tank 4, an electronic expansion valve 5 and a gas-liquid separator 6, wherein the energy storage cabinet 1 is provided with a plurality of parallel battery packs 111, wherein the battery pack 111 is provided with a battery cell 112, wherein each battery pack 111 is connected in series with a group of quick-release stop valves 113, wherein the quick-release stop valves 113 are respectively connected to the two ends of the battery pack 111, wherein the interior of the battery pack 111 is filled with an insulating liquid 114 as a whole, wherein one end of the condenser 3 is communicated with the compressor 2, wherein the compressor 2 is communicated with the gas-liquid separator 6, wherein the gas-liquid separator 6 is connected to one end of the battery pack 111, wherein the other end of the condenser 3 is communicated with the liquid storage tank 4, wherein the liquid storage tank 4 is connected to one end of the electronic expansion valve 5, wherein the other end of the electronic expansion valve 5 is connected to the quick-release stop valve 113.

[0095] The energy storage cabinet 1 is further provided with a plurality of evaporators, which are integrated with the battery pack 111 ; the battery pack 111 adopts a heat exchange pipeline that surrounds the battery.

[0096] like Figure 4 As shown, a direct cooling pipeline 115 is provided in the battery pack 111 , and the direct cooling pipeline 115 is arranged on the top of the battery cell 112 and around the battery cell 112 ; the direct cooling pipeline is a copper tube, an aluminum tube, a copper tube bracket or an aluminum tube bracket.

[0097] The gas-liquid separator 6 is provided with a short tube connection end and a long tube connection end. The short tube connection end is communicated with the compressor 2 , and the long tube connection end is connected to one end of the battery pack 111 .

[0098] An intake pressure sensor 7 and a low pressure switch 8 are provided between the compressor 2 and the gas-liquid separator 6 . The intake pressure sensor 7 is located on a side close to the compressor 2 , and the low pressure switch 8 is located on a side close to the gas-liquid separator 6 .

[0099] A high-pressure switch 9 and an exhaust temperature sensor 10 are provided between the compressor 2 and the condenser 3 . The exhaust temperature sensor 10 is located on a side close to the compressor 2 , and the high-pressure switch 9 is located on a side close to the condenser 3 .

[0100] A pre-valve pressure sensor 11, a pre-valve temperature sensor 12, a filter 13 and a sight glass 14 are sequentially arranged between the liquid storage tank 4 and the electronic expansion valve 5 along the material flow direction, and the exhaust temperature sensor 10 is electrically connected to a controller arranged in the system.

[0101] A control method for an immersion refrigerant direct cooling energy storage temperature control system comprises the following steps:

[0102] S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command;

[0103] S2, the controller receives the power on / off command from the host computer;

[0104] S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and starts according to the start-up sequence; otherwise, the unit is kept in the off state;

[0105] S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor;

[0106] S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7;

[0107] S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

[0108] When starting and shutting down the temperature control system, the shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor must be executed.

[0109] During the dehumidification process in step S2, the evaporator is started, the low-pressure switch 8 is turned on, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the exhaust port of the compressor 2, the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0110] In the liquid cooling heat dissipation process of step S4, the low-pressure switch 8 is turned on, the high-pressure switch 9 is turned off, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, the gas-liquid separator 6, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0111] In the evaporator heating of step S6 and step S7, the electronic expansion valve 5 and the high-pressure switch 9 are closed, the low-pressure switch 8 is opened, and the evaporator, the gas-liquid separator 6 and the compressor 2 are all working.

[0112] The insulating liquid comprises raw materials in the following percentages: 95% of base oil, 2% of antioxidant, 1% of corrosion inhibitor, 0.5% of inhibitor, and 1.5% of flame retardant.

[0113] The base oil is API-II; the antioxidant is 2,6-di-tert-butylphenol; and the corrosion inhibitor is isooctanoic acid.

[0114] The inhibitor is a benzotriazole derivative. The flame retardant is triisopropylphenyl phosphate.

[0115] Example 4

[0116] See Figure 1-2 , an immersion refrigerant direct cooling energy storage temperature control system, comprising an energy storage cabinet 1, a compressor 2, a condenser 3, a liquid storage tank 4, an electronic expansion valve 5 and a gas-liquid separator 6, wherein the energy storage cabinet 1 is provided with a plurality of parallel battery packs 111, wherein the battery pack 111 is provided with a battery cell 112, wherein each battery pack 111 is connected in series with a group of quick-release stop valves 113, wherein the quick-release stop valves 113 are respectively connected to the two ends of the battery pack 111, wherein the interior of the battery pack 111 is filled with an insulating liquid 114 as a whole, wherein one end of the condenser 3 is communicated with the compressor 2, wherein the compressor 2 is communicated with the gas-liquid separator 6, wherein the gas-liquid separator 6 is connected to one end of the battery pack 111, wherein the other end of the condenser 3 is communicated with the liquid storage tank 4, wherein the liquid storage tank 4 is connected to one end of the electronic expansion valve 5, wherein the other end of the electronic expansion valve 5 is connected to the quick-release stop valve 113.

[0117] The energy storage cabinet 1 is further provided with a plurality of evaporators, which are integrated with the battery pack 111 ; the battery pack 111 adopts a heat exchange pipeline that surrounds the battery.

[0118] like Figure 2 The battery pack 111 shown adopts a bottom refrigerant direct cooling plate method.

[0119] The gas-liquid separator 6 is provided with a short tube connection end and a long tube connection end. The short tube connection end is communicated with the compressor 2 , and the long tube connection end is connected to one end of the battery pack 111 .

[0120] An intake pressure sensor 7 and a low pressure switch 8 are provided between the compressor 2 and the gas-liquid separator 6 . The intake pressure sensor 7 is located on a side close to the compressor 2 , and the low pressure switch 8 is located on a side close to the gas-liquid separator 6 .

[0121] A high-pressure switch 9 and an exhaust temperature sensor 10 are provided between the compressor 2 and the condenser 3 . The exhaust temperature sensor 10 is located on a side close to the compressor 2 , and the high-pressure switch 9 is located on a side close to the condenser 3 .

[0122] A pre-valve pressure sensor 11, a pre-valve temperature sensor 12, a filter 13 and a sight glass 14 are sequentially arranged between the liquid storage tank 4 and the electronic expansion valve 5 along the material flow direction, and the exhaust temperature sensor 10 is electrically connected to a controller arranged in the system.

[0123] A control method for an immersion refrigerant direct cooling energy storage temperature control system comprises the following steps:

[0124] S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command;

[0125] S2, the controller receives the power on / off command from the host computer;

[0126] S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and starts according to the start-up sequence; otherwise, the unit is kept in the off state;

[0127] S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor;

[0128] S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7;

[0129] S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

[0130] When starting and shutting down the temperature control system, the shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor must be executed.

[0131] During the dehumidification process in step S2, the evaporator is started, the low-pressure switch 8 is turned on, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the exhaust port of the compressor 2, the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0132] In the liquid cooling heat dissipation process of step S4, the low-pressure switch 8 is turned on, the high-pressure switch 9 is turned off, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, the gas-liquid separator 6, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0133] In the evaporator heating of step S6 and step S7, the electronic expansion valve 5 and the high-pressure switch 9 are closed, the low-pressure switch 8 is opened, and the evaporator, the gas-liquid separator 6 and the compressor 2 are all working.

[0134] The insulating liquid comprises raw materials in the following percentages: 85% of base oil, 5% of antioxidant, 5% of corrosion inhibitor, 3.55% of inhibitor and 1.5% of flame retardant.

[0135] The base oil is API-III; the carbon number of the API-III base oil is 10-60, and the kinematic viscosity at 100° C. is 1.0-8.0 mm2·s-1; the API-III base oil is an ADbase series base oil.

[0136] The antioxidant is 4,4'-methylenebis(2,6-di-tert-butylphenol).

[0137] The corrosion inhibitor is methylbenzotriazole.

[0138] The inhibitor is a methylbenzotriazole derivative.

[0139] The flame retardant is tri(xylene) phosphate.

[0140] Example 5

[0141] An immersion refrigerant direct cooling energy storage temperature control system comprises an energy storage cabinet 1, a compressor 2, a condenser 3, a liquid storage tank 4, an electronic expansion valve 5 and a gas-liquid separator 6, wherein the energy storage cabinet 1 is provided with a plurality of parallel battery packs 111, wherein the battery pack 111 is provided with a battery cell 112, wherein each battery pack 111 is connected in series with a group of quick-release stop valves 113, wherein the quick-release stop valves 113 are respectively connected to the two ends of the battery pack 111, wherein the interior of the battery pack 111 is filled with an insulating liquid 114 as a whole, wherein one end of the condenser 3 is communicated with the compressor 2, wherein the compressor 2 is communicated with the gas-liquid separator 6, wherein the gas-liquid separator 6 is connected to one end of the battery pack 111, wherein the other end of the condenser 3 is communicated with the liquid storage tank 4, wherein the liquid storage tank 4 is connected to one end of the electronic expansion valve 5, and wherein the other end of the electronic expansion valve 5 is connected to the quick-release stop valve 113.

[0142] The energy storage cabinet 1 is further provided with a plurality of evaporators, which are integrated with the battery pack 111 ; the battery pack 111 adopts a heat exchange pipeline that surrounds the battery.

[0143] like Figure 5 The battery cells in the battery pack shown are surrounded by copper tubes.

[0144] The gas-liquid separator 6 is provided with a short tube connection end and a long tube connection end. The short tube connection end is communicated with the compressor 2 , and the long tube connection end is connected to one end of the battery pack 111 .

[0145] An intake pressure sensor 7 and a low pressure switch 8 are provided between the compressor 2 and the gas-liquid separator 6 . The intake pressure sensor 7 is located on a side close to the compressor 2 , and the low pressure switch 8 is located on a side close to the gas-liquid separator 6 .

[0146] A high-pressure switch 9 and an exhaust temperature sensor 10 are provided between the compressor 2 and the condenser 3 . The exhaust temperature sensor 10 is located on a side close to the compressor 2 , and the high-pressure switch 9 is located on a side close to the condenser 3 .

[0147] A pre-valve pressure sensor 11, a pre-valve temperature sensor 12, a filter 13 and a sight glass 14 are sequentially arranged between the liquid storage tank 4 and the electronic expansion valve 5 along the material flow direction, and the exhaust temperature sensor 10 is electrically connected to a controller arranged in the system.

[0148] A control method for an immersion refrigerant direct cooling energy storage temperature control system comprises the following steps:

[0149] S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command;

[0150] S2, the controller receives the power on / off command from the host computer;

[0151] S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and starts according to the start-up sequence; otherwise, the unit is kept in the off state;

[0152] S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor;

[0153] S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7;

[0154] S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

[0155] When starting and shutting down the temperature control system, the shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor must be executed.

[0156] During the dehumidification process in step S2, the evaporator is started, the low-pressure switch 8 is turned on, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the exhaust port of the compressor 2, the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0157] In the liquid cooling heat dissipation process of step S4, the low-pressure switch 8 is turned on, the high-pressure switch 9 is turned off, and the compressor 2 and the condenser 3 are both working; the refrigerant flows through the condenser 3, the liquid storage tank 4, the electronic expansion valve 5, the battery pack 111, the gas-liquid separator 6, and the air intake of the compressor 2; the controller controls the opening of the electronic expansion valve 5 and the speed of the evaporator fan according to the indoor temperature or indoor humidity measured by the pre-valve temperature sensor 12, so that the evaporator supplies air to dissipate heat or dehumidify the battery pack 111.

[0158] In the evaporator heating of step S6 and step S7, the electronic expansion valve 5 and the high-pressure switch 9 are closed, the low-pressure switch 8 is opened, and the evaporator, the gas-liquid separator 6 and the compressor 2 are all working.

[0159] The insulating liquid comprises raw materials in the following percentages: 95% of base oil, 1% of antioxidant, 3% of corrosion inhibitor, 0.1% of inhibitor, and 0.9% of flame retardant.

[0160] The base oil is API-III; the carbon number of the API-III base oil is 10-60, and the kinematic viscosity at 100° C. is 1.0-8.0 mm2·s-1; the API-III base oil is a SINOPURE series base oil.

[0161] The antioxidant is 2,6-di-tert-butyl-α-dimethylamino-p-cresol. The corrosion inhibitor is benzotriazole. The inhibitor is a methylbenzotriazole derivative. The flame retardant is hexachlorobutadiene.

[0162] Comparative Example 1

[0163] The difference between this comparative example and the above-mentioned Example 2 is that in this comparative example, vegetable oil is not used to replace the base oil in the raw material of the insulating liquid. The rest of the contents of this comparative example are the same as those of Example 2 and will not be repeated here.

[0164] The performance tests were performed on the soft materials prepared in Specific Example 2 and Comparative Example 1 respectively.

[0165] The freezing point test of the solutions of the embodiments and comparative examples was carried out according to SH / T 0090 "Determination of Freezing Point of Engine Coolants" to reflect the antifreeze performance; the thermal conductivity test was carried out according to ASTM D7896 "Standard Test Method for Determination of Thermal Conductivity, Thermal Diffusivity and Volume Heat Capacity of Engine Coolants and Related Fluids by Transient Hot Wire Liquid Thermal Conductivity Method" to reflect the heat transfer performance; the phase change latent heat was measured according to a differential scanning calorimeter (DSC) to reflect the heat transfer performance; the electrical conductivity was carried out according to GB / T6682 "Specifications and Test Methods for Water for Analytical Laboratories" to reflect the insulation performance; the dynamic viscosity (0°C) was carried out according to GB / T 265 "Determination of Kinematic Viscosity of Petroleum Products and Calculation of Dynamic Viscosity" to reflect the low-temperature fluidity, and the results are shown in Table 1.

[0166] Table 1

[0167]

[0168] It can be seen from the above table that the insulating liquid prepared in the present invention has good comprehensive properties of antifreeze performance, thermal conductivity and low-temperature fluidity.

[0169] From the comparison between Example 2 and Comparative Example 1, it can be seen that under the same conditions, adding insulating cooling oil and sebacic acid to the insulating liquid formula can make the prepared insulating liquid have good comprehensive properties of antifreeze performance, thermal conductivity and low-temperature flow performance, and can be widely used.

[0170] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. An immersion refrigerant direct cooling energy storage temperature control system, characterized in that: It includes an energy storage cabinet, a compressor, a condenser, a liquid storage tank, an electronic expansion valve and a gas-liquid separator. The energy storage cabinet is provided with a plurality of parallel battery packs, the battery packs are provided with battery cells, each battery pack has a group of quick-release stop valves, the quick-release stop valves are respectively connected to the two ends of the battery pack, the battery pack is filled with insulating liquid as a whole, one end of the condenser is connected to the compressor, the compressor is connected to the gas-liquid separator, the gas-liquid separator is connected to one end of the battery pack, the other end of the condenser is connected to the liquid storage tank, the liquid storage tank is connected to one end of the electronic expansion valve, and the other end of the electronic expansion valve is connected to the quick-release stop valve.

2. The immersion refrigerant direct cooling energy storage temperature control system according to claim 1, characterized in that: The energy storage cabinet is also provided with a plurality of evaporators, which are integrated with the battery pack; the battery pack adopts a heat exchange pipeline surrounding the battery.

3. The immersion refrigerant direct cooling energy storage temperature control system according to claim 2 is characterized in that: The battery pack adopts a bottom refrigerant direct cooling plate method.

4. The immersion refrigerant direct cooling energy storage temperature control system according to claim 2, characterized in that: A direct cooling pipeline is provided in the battery pack, and the direct cooling pipeline is arranged on the top of the battery cell and around the battery cell; the direct cooling pipeline is a copper tube, an aluminum tube, a copper tube bracket or an aluminum tube bracket.

5. An immersion refrigerant direct cooling energy storage temperature control system according to any one of claims 1 to 4, characterized in that: A short tube connecting end and a long tube connecting end are provided in the gas-liquid separator, the short tube connecting end is communicated with the compressor, and the long tube connecting end is connected to one end of the battery pack.

6. An immersion refrigerant direct cooling energy storage temperature control system according to any one of claims 1 to 4, characterized in that: An air suction pressure sensor and a low pressure switch are provided between the compressor and the gas-liquid separator. The air suction pressure sensor is located on a side close to the compressor, and the low pressure switch is located on a side close to the gas-liquid separator.

7. An immersion refrigerant direct cooling energy storage temperature control system according to any one of claims 1 to 4, characterized in that: A high-pressure switch and an exhaust temperature sensor are provided between the compressor and the condenser. The exhaust temperature sensor is located on a side close to the compressor, and the high-pressure switch is located on a side close to the condenser.

8. The immersion refrigerant direct cooling energy storage temperature control system according to claim 7, characterized in that: A pre-valve pressure sensor, a pre-valve temperature sensor, a filter and a sight glass are sequentially arranged between the liquid storage tank and the electronic expansion valve along the material direction, and the exhaust temperature sensor and the pre-valve temperature sensor are both electrically connected to a controller arranged in the system.

9. A control method for an immersion refrigerant direct cooling energy storage temperature control system as claimed in claim 7, characterized in that: The steps include: S1. The temperature control system controller receives the command from the host computer BMS, wakes up the temperature control system, establishes a communication connection, and compares the battery cell temperature detected by the BMS with the set temperature, makes a judgment and analysis, and issues a command; S2, the controller receives the power on / off command from the host computer; S3, the controller determines whether the current battery pack is in the charging and discharging state or the standby state; at the same time, it determines whether the battery cell temperature is greater than the preset temperature Ha; if so, the unit is started S4 and turned on according to the start-up sequence; otherwise, the unit is kept turned off; S4, start the temperature control unit, according to the start-up sequence H1, first open the electronic expansion valve, then delay the start of the fan, and finally start the compressor; S5, S6 The controller continuously detects the cooling demand and determines whether the current temperature is greater than the preset value Tc; if so, the battery pack is continuously liquid-cooled to maintain the cooling H1; otherwise, it proceeds to step S7; S7, the controller follows the shutdown sequence H2; first shut down the compressor, then delay starting the fan, and finally close the electronic expansion valve.

10. The immersion refrigerant direct cooling energy storage temperature control system according to claim 9, characterized in that: When starting and shutting down the temperature control system, the shutdown or start-up delay sequence of the fan, electronic expansion valve and compressor must be executed.

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