Battery thermal management system

Abstract

The utility model discloses a battery thermal management system. The battery thermal management system comprises a battery module, a control module, a timer, an air conditioning system heat exchanger, a four-way reversing valve and a compressor, the battery module comprises a shell, a semiconductor cooler is arranged on the outer surface of the shell, a refrigerant pipeline is arranged in the shell, a plurality of battery cells are arranged in an area defined by the refrigerant pipeline, the battery cells are all arranged in heat conduction pipes with fins in a sleeved mode, and gaps in the shell are filled with PCM phase change materials. Temperature sensors are respectively arranged on the inner surface of the shell and the upper and lower surfaces of the battery cell; a heat flux density sensor is arranged in the PCM phase change material; a first electromagnetic valve and a second electromagnetic valve are arranged at an inlet and an outlet of the refrigerant pipeline respectively, the first electromagnetic valve is connected with an air-conditioning system heat exchanger, and the air-conditioning system heat exchanger is connected with a compressor and the second electromagnetic valve through a four-way reversing valve. And the timer is connected with the semiconductor cooler, the first electromagnetic valve and the second electromagnetic valve. According to the utility model, accurate temperature control can be realized, and the temperature uniformity and safety of the battery are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery thermal management system. Background Art

[0002] For batteries that are the power source of electric vehicles, the suitable operating temperature range of lithium-ion power batteries is only 20℃~40℃. The batteries face problems such as thermal runaway at high temperatures and limited charging and discharging performance at low temperatures. At the same time, battery modules are generally composed of high-energy density cells. There are differences in the heat generated by the cells during the charging and discharging process, which makes the temperature inside the battery module uneven. There are also temperature differences between different modules, resulting in reduced service life and increased internal resistance. These have hindered the development of electric vehicles to a certain extent. Therefore, an efficient, stable and safe battery thermal management system is particularly important.

[0003] At present, the mainstream battery thermal management technologies are mostly air cooling and liquid cooling. New thermal management methods such as PCM (Phase Change Material) phase change and heat pipes have emerged, but most of them are single passive battery thermal management. At the same time, their operating mode mainly considers high-temperature cooling of battery packs. There is little research on the limited low-temperature performance of batteries, making it difficult to achieve efficient and stable operation of electric vehicles in all seasons and all working conditions. In addition, due to the different positions of battery cells in the battery module and the difference in energy density, the temperature uniformity of the battery module is poor. Utility Model Content

[0004] The purpose of the present invention is to provide a battery thermal management system to address the problems in the above-mentioned prior art, combining passive battery thermal management with active thermal management to achieve precise temperature control and improve the temperature uniformity and safety of the battery module.

[0005] In order to achieve the above purpose, the utility model has the following technical solutions:

[0006] A battery thermal management system, comprising a battery module, a control module, a timer, an air conditioning system heat exchanger, a four-way reversing valve and a compressor;

[0007] The battery module includes a shell, a semiconductor refrigerator is arranged on the outer surface of the shell, a refrigerant pipeline is arranged around the inside of the shell, a refrigerant flows in the refrigerant pipeline, a plurality of battery cells are arranged inside the area surrounded by the refrigerant pipeline, the battery cells are all set in a heat-conducting tube with fins, and the gap inside the shell is filled with PCM phase change material; a first temperature sensor is arranged on the inner surface of the shell, a second temperature sensor and a third temperature sensor are arranged on the upper and lower surfaces of the battery cell respectively, and a heat flux density sensor is distributed in the PCM phase change material; a first solenoid valve and a second solenoid valve are respectively arranged at the inlet and outlet of the refrigerant pipeline, the first solenoid valve is connected to the air-conditioning system heat exchanger, and the air-conditioning system heat exchanger is connected to the compressor and the second solenoid valve through a four-way reversing valve;

[0008] The timer is connected to the semiconductor refrigerator and the first solenoid valve and the second solenoid valve, and the timer detects the time for the semiconductor refrigerator or the refrigerant pipeline to dissipate heat or heat the battery core alone;

[0009] The semiconductor refrigerator, the first solenoid valve, the second solenoid valve, the timer, the four-way reversing valve, the compressor, the first temperature sensor, the second temperature sensor, the third temperature sensor and the heat flux density sensor are all connected to the control module; the control module controls the current size and direction of the semiconductor refrigerator, the opening of the first solenoid valve and the second solenoid valve, the direction of the four-way reversing valve and the speed of the compressor according to the temperature feedback signals of the first temperature sensor, the second temperature sensor and the third temperature sensor, the heat flux feedback signal of the heat flux density sensor and the time feedback signal of the timer.

[0010] As a preferred solution, the inner wall of the refrigerant pipeline is provided with an internal thread for circulating the refrigerant, and the outer wall of the refrigerant pipeline is distributed with fins; the refrigerant pipeline is arranged in a coil type around the inside of the shell; phase change materials are distributed along the refrigerant pipeline to achieve integrated energy storage and heat exchange; the battery thermal management system is coupled and interacted with the air-conditioning system through the refrigerant pipeline; the refrigerant flow direction is changed by a four-way reversing valve to achieve cold or heat storage in the battery module.

[0011] As a preferred solution, the semiconductor refrigerator is any one of a single-stage semiconductor cooling plate, a double-stage semiconductor cooling plate or a multi-stage semiconductor cooling plate;

[0012] The cold end face of the semiconductor refrigerator is attached to the outer surface of the shell through a flexible thermally conductive material, and the hot end face is connected to the hot end radiator through a flexible thermally conductive material. The hot end radiator has a refrigerant outlet and an inlet, and the refrigerant flows inside. The semiconductor refrigerator can achieve mutual switching between the cold end face and the hot end face by changing the direction of the current.

[0013] As a preferred solution, a 3D temperature averaging plate is provided on the inner surface of the shell, and the first temperature sensor is provided on the inner surface of the 3D temperature averaging plate;

[0014] The shell is in the shape of a regular hexagonal prism, the outer surface of the shell is attached to the semiconductor refrigerator through a flexible heat-conducting material, and the inner surface of the shell is attached to the 3D temperature-averaging plate through a flexible heat-conducting material.

[0015] As a preferred solution, the interior of the heat-conducting tube with fins is bonded and connected to the battery core via a flexible heat-conducting material.

[0016] As a preferred solution, the flexible thermally conductive material is any one of thermally conductive silicone grease, thermally conductive pad, thermally conductive rubber and metal film.

[0017] As a preferred solution, the shell is made of any one of copper, stainless steel, aluminum and aluminum alloy.

[0018] As a preferred solution, the surface fins of the heat pipe are composed of a combination of conical fins, corrugated fins and rectangular fins. The rectangular fins and conical fins are distributed in two areas, and the corrugated fins are arranged between two adjacent fins.

[0019] As a preferred solution, the PCM phase change material is any one of n-dodecane, calcium chloride hexahydrate, paraffin, a mixture of paraffin and graphene, and phase change microcapsules.

[0020] As a preferred solution, the compressor adopts a variable frequency compressor, which can automatically adjust the speed according to demand, and then adjust the temperature of the refrigerant pipeline.

[0021] Compared with the prior art, the battery thermal management system of the present utility model has at least the following beneficial effects:

[0022] By coupling passive thermal management and active thermal management for temperature control, different control strategies make them work separately or in coupling, reducing the property differences of multiple cells in the battery module under different temperatures, improving the temperature uniformity of the battery, and due to the introduction of semiconductor refrigeration technology, the utility model has the characteristics of energy saving, environmental protection, high efficiency and fastness. The utility model realizes the integration of energy storage and heat exchange by combining the refrigerant pipeline with the PCM phase change material, ensuring the heat dissipation and heating of the battery cell while realizing the storage of cold / heat, and improving the energy utilization rate. The control module of the utility model controls the current size and direction of the semiconductor refrigerator, the opening of the first solenoid valve and the second solenoid valve, the direction of the four-way reversing valve and the speed of the compressor according to the temperature feedback signals of the first temperature sensor, the second temperature sensor and the third temperature sensor, the heat flow feedback signal of the heat flux density sensor and the time feedback signal of the timer, and can realize the zoned precise temperature control through different control methods, thereby achieving the purpose of efficient and stable operation in all seasons and all working conditions. When the temperature difference reaches the set value, the heat dissipation and heating treatment can be carried out, ensuring the temperature uniformity of the battery module and reducing the risk of temperature gradient. The utility model is more convenient for temperature control, can avoid long-term working without heat dissipation / heating, and can accurately control the temperature while saving system costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of a battery thermal management system according to an embodiment of the utility model;

[0024] Figure 2 This is a schematic diagram of the exploded three-dimensional structure of a battery module according to an embodiment of the utility model;

[0025] Figure 3 This is a schematic diagram of the structure of a heat pipe with fins in a battery thermal management system according to an embodiment of the utility model;

[0026] Figure 4 This is a schematic diagram of remote control of a battery thermal management system according to an embodiment of the utility model;

[0027] Figure 5 This is a control logic diagram of the battery thermal management system in the heat dissipation cooling mode of the embodiment of the utility model;

[0028] Figure 6 This is a control logic diagram of the battery thermal management system in the insulation and heating mode of the embodiment of the utility model;

[0029] In the attached figure: 1-shell; 2-PCM phase change material; 3-semiconductor refrigerator; 4-battery core; 5-heat pipe; 6-refrigerant pipeline; 7-3D temperature plate; 8-first solenoid valve; 9-second solenoid valve; 10-control module; 11-timer; 12-air conditioning system heat exchanger; 13-four-way reversing valve; 14-compressor; T1-first temperature sensor; T2-second temperature sensor; T3-third temperature sensor; q1-heat flux density sensor; 51-conical fin; 52-corrugated fin; 53-rectangular fin. DETAILED DESCRIPTION

[0030] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0031] The embodiment of the utility model proposes a battery thermal management system, which introduces a regular hexagonal prism battery module, which improves the energy density of the battery module while making the arrangement between the battery cells more reasonable, making the system more compact and improving the temperature uniformity of the battery; a semiconductor refrigerator is used to be closely attached to the outer surface of the regular hexagonal prism battery module, and the hot and cold ends can perform active thermal management on the battery module by changing the magnitude and direction of the current to achieve precise temperature control; a 3D temperature equalizing plate is introduced and arranged on the inner surface of the regular hexagonal prism battery module, which helps to improve the temperature uniformity of the battery module and reduce the performance changes of the battery system caused by temperature differences; a finned plate with a flexible thermal conductive material is embedded outside the battery cell The heat pipe enhances the heat exchange of the battery cell, which is beneficial to its heat dissipation and heating; the battery module and the air-conditioning system are coupled through the refrigerant pipeline. By increasing the opening of the solenoid valve and adjusting the speed of the compressor, the cooling / heating capacity can be increased and the temperature of the battery module can be adjusted. At the same time, the refrigerant pipeline can be combined with the phase change material to realize the integration of heat exchange and energy storage; the passive battery thermal management technology is combined with the active thermal management technology. Through their separate or coupled work, the precise temperature control of the battery system is achieved, the property differentiation of multiple cells in the battery module under different temperatures is reduced, and the battery temperature uniformity and safety are improved.

[0032] See also Figure 1 and Figure 2The battery thermal management system of the utility model embodiment includes a shell 1, a PCM phase change material 2, a semiconductor refrigerator 3, a battery cell 4, a heat pipe 5 with fins, a refrigerant pipeline 6, a 3D temperature averaging plate 7, a first solenoid valve 8, a second solenoid valve 9, an air conditioning system heat exchanger 12, a four-way reversing valve 13 and a compressor 14. In the utility model embodiment, the cold ends of the six semiconductor refrigerators 3 are closely attached to the outer surface of the shell 1 of a regular hexagonal prism; the six 3D temperature averaging plates 7 are closely attached to the inner surface of the shell 1 of a regular hexagonal prism; the battery cell 4 is nested in the heat pipe 5 with fins through a flexible thermal conductive material and is evenly arranged in an array in the battery shell 1; the first solenoid valve 8 and the second solenoid valve 9 are installed at the inlet and outlet of the refrigerant pipeline 6; the refrigerant pipeline 6 is coiled around the outermost heat pipe 5 with fins; the refrigerant pipeline 6 circulates There is a refrigerant and phase change materials with gradually increasing phase change temperature are distributed along the process; the gap between the shell 1 and the heat pipe 5 with fins, the refrigerant pipeline 6 and the 3D temperature averaging plate 7 is filled with PCM phase change material 2 and is tightly combined with the PCM phase change material 2; the first temperature sensor T1, the second temperature sensor T2 and the third temperature sensor T3 are respectively arranged on the side away from the 3D temperature averaging plate 7 and the battery shell 1, and on the upper and lower surfaces of the battery core 4, and the heat flux density sensor q1 is distributed in the PCM phase change material 2.

[0033] The timer 11 is connected to the semiconductor refrigerator 3 and the first solenoid valve 8 and the second solenoid valve 9. The timer 11 detects the time for the semiconductor refrigerator 3 or the refrigerant pipeline 6 to dissipate heat or heat the battery cell 4 alone.

[0034] See also Figure 4 The semiconductor refrigerator 3, the first solenoid valve 8, the second solenoid valve 9, the timer 11, the four-way reversing valve 13, the compressor 14, the first temperature sensor T1, the second temperature sensor T2, the third temperature sensor T3 and the heat flux density sensor q1 in the battery thermal management system of the utility model embodiment are all connected to the control module 10. The control module 10 controls the current size and direction of the semiconductor refrigerator 3, the opening of the first solenoid valve 8 and the second solenoid valve 9, the direction of the four-way reversing valve 13 and the start and stop and speed of the compressor 14 according to the temperature feedback signals of the first temperature sensor T1, the second temperature sensor T2 and the third temperature sensor T3, the heat flux feedback signal of the heat flux density sensor q1 and the time feedback signal of the timer 11.

[0035] The refrigerant pipe 6 of the embodiment of the utility model has an internal thread for circulating refrigerant, and fins are distributed on the outside; the refrigerant pipe is coiled around the outermost heat-conducting pipe 5 with fins; phase change materials are distributed along the refrigerant pipe 6, which can realize the integration of energy storage and heat exchange; the refrigerant pipe 6 is connected to the air-conditioning system heat exchanger 12 through the first solenoid valve 8, and is connected to the air-conditioning system compressor 14 through the second solenoid valve 9, and the battery thermal management system is coupled and interacted with the air-conditioning system through the refrigerant pipe 6. The semiconductor refrigerator 3 of the embodiment of the utility model is a multi-stage semiconductor refrigeration sheet, so as to match the temperature control requirements of the high-power thermal management system; the cold end face of the semiconductor refrigerator 3 faces inward and is attached to the outer surface of the shell 1 through a flexible thermal conductive material, and the hot end face faces outward and is connected to the hot end radiator through a flexible thermal conductive material, and the hot end radiator has a refrigerant outlet and an inlet, and the refrigerant can flow inside; the semiconductor refrigerator 3 can realize the mutual switching of the cold end face and the hot end face by changing the direction of the current.

[0036] The shell 1 of the embodiment of the utility model is in the form of a regular hexagonal prism, the outer surface is in contact with the semiconductor refrigerator 3 through a flexible heat-conducting material, and the inner surface is in close contact with the 3D temperature equalizing plate 7 through a flexible heat-conducting material. The battery shell 1 is made of copper, and can also be made of any one of stainless steel, aluminum or aluminum alloy, which can meet the requirements of good thermal conductivity. The shell 1 is used to accommodate battery cells and constitute a battery module thermal management system, and can also transfer heat.

[0037] The heat pipe 5 with fins in the embodiment of the utility model is closely connected to the battery core 4 through a flexible heat conductive material. Figure 3 As shown, the surface fins of the heat pipe 5 with fins are composed of a combination of a conical fin 51, a corrugated fin 52, and a rectangular fin 53, wherein the rectangular fin 53 and the conical fin 51 are distributed in two areas, and a corrugated fin 52 is arranged between two adjacent fins. The heat pipe 5 with fins is nested outside the battery cell 4 to increase the heat transfer area to a certain extent, and enhance the heat exchange capacity of the battery cell 4.

[0038] The flexible heat-conductive material used in the embodiment of the utility model is a metal film, and can also be any one of thermal grease, thermal pads and thermal rubber. It can effectively conduct heat and help the radiator transfer heat to the surrounding environment more quickly. In addition, it can reduce the heat exchange thermal resistance, fill the gaps, minimize the air thermal resistance, and improve the heat dissipation efficiency.

[0039] The PCM phase change material 2 in the embodiment of the utility model is a mixture of paraffin and graphene. Its solid phase change property can be tightly filled in the battery housing 1 to help regulate temperature, absorb or release heat, and improve the efficiency and stability of the system. The PCM phase change material 2 can also be any one of n-dodecane, calcium chloride hexahydrate, paraffin and phase change microcapsules.

[0040] The compressor 14 used in the embodiment of the utility model is a variable frequency compressor, which can automatically adjust the speed according to demand, and then adjust the temperature of the refrigerant pipeline 6, and is suitable for various working conditions.

[0041] See also Figure 5 and Figure 6 The control method of the battery thermal management system using the embodiment of the utility model specifically includes:

[0042] First, set the parameters, T s Indicates the set temperature, where T sl , T sl-1 , T sl-2 They represent the low temperature rated setting temperature of 15℃, the low temperature first setting temperature of 5℃, and the low temperature second setting temperature of -15℃ respectively; T sh , T sh-1 , T sh-2 They represent the high temperature rated setting temperature of 45°C, the high temperature first setting temperature of 55°C, and the high temperature second setting temperature of 65°C respectively; t represents the setting time, t 1 ,t 2 The time for the semiconductor refrigerator 3 and the refrigerant pipeline 6 to work separately is set respectively; k 1 is the surface temperature of the 3D temperature plate 7 measured by the first temperature sensor T1, k 2 is the upper surface temperature of the battery cell 4 measured by the second temperature sensor T2, k 3 is the lower surface temperature of the battery cell 4 measured by the third temperature sensor T3, f 1 、f 2 is the opening of the first solenoid valve 8 and the second solenoid valve 9, the initial opening is 1 / 5 of the full opening, w 1 is the heat flow value of PCM phase change material 2 measured by the heat flux density sensor;

[0043] 1) When T sl ≤(k 2 +k 3 ) / 2≤T sh When , it means that the battery cell 4 is basically in the normal working temperature range. At this time, the system is in automatic adjustment mode, the semiconductor refrigerator 3 is not started, the refrigerant pipeline 6 is closed, and the PCM phase change material 2 and the 3D temperature plate 7 can ensure that the system temperature is normal; the control module 10 scans the temperature every one minute to determine the logical relationship between the temperatures;

[0044] 2) When T sh <(k 2 +k 3 ) / 2, it indicates that the temperature of the battery cell 4 gradually increases, and the system enters the cooling mode;

[0045] 3) When T sh <(k 2 +k3 ) / 2≤T sh-1 At the same time, k 3 <k 2 +0.7, indicating that the temperature difference between the upper and lower surfaces of the battery cell 4 is small, and the heat flux density in the PCM phase change material 2 is monitored. 1 The sharp increase indicates that a phase change is taking place at this time, the semiconductor refrigerator 3 is not started, and the refrigerant pipeline 6 is closed; the control module 10 scans every 5 seconds to determine the logical relationship between the temperatures and the heat flux w 1 , when w 1 Stable and k 3 >k 2 +0.7, the heat flux density sensor q1, the second temperature sensor T2 and the third temperature sensor T3 feed back the temperature signal and the heat flux signal to the control module 10, and control the semiconductor refrigerator 3 or the refrigerant pipeline 6 to dissipate heat for the system alone; adjust the input current of the semiconductor refrigerator 3 or adjust the opening of the first solenoid valve 8, at this time the first solenoid valve 8 has a throttling function, and the compressor 14 runs at a low speed to match the temperature. When k 2 and k 3 When the gap increases, the control module 10 controls the input current of the semiconductor refrigerator 3 to gradually increase or controls the opening of the first solenoid valve 8 to gradually increase, but the maximum current is less than the current Imax corresponding to its maximum cooling capacity working condition, and the maximum opening of the first solenoid valve 8 is 80% of the full opening capacity;

[0046] 4) When the timer detects the semiconductor refrigerator 3 or the refrigerant pipeline 6 running alone for a certain time t e With t r Satisfy t e >t 1 or r >t 2 Logical relationship, and at this time the temperature satisfies the logical relationship T sh <(k 2 +k 3 ) / 2≤T sh-1 , the temperature and time signals are fed back to the control module 10, which controls the semiconductor refrigerator 3 and the refrigerant pipeline 6 to work simultaneously, generating cold energy to cool the system;

[0047] 5) When T sh-1 <(k 2 +k 3 ) / 2≤T sh-2 When k 1 <(k 2 +k 3) / 2, indicating that the heat dissipation effect is not ideal at this time. At this time, the temperature signal is fed back to the control module 10, and the first solenoid valve 8 and the second solenoid valve 9 on the refrigerant pipeline are controlled to be in the maximum opening mode. The speed of the compressor 14 gradually increases. At this time, the temperature of the battery cell 4 can be effectively reduced by the refrigerant direct cooling method. The control module scans k every 5s. 2 and k 3 , when (k 2 +k 3 ) / 2 tends to be stable, the semiconductor refrigerator 3 starts to be powered at the maximum current. 1 +0.7>(k 2 +k 3 ) / 2, the control module 10 controls the current of the semiconductor refrigerator 3 and the opening of the first solenoid valve 8 to gradually decrease until the power is cut off and closed;

[0048] 6) When (k 2 +k 3 ) / 2>k 1 >T sh-2 When k is , it means that the battery is close to thermal runaway. The control module 10 controls the semiconductor refrigerator 3 and the refrigerant pipeline 6 to dissipate heat for the system at the same time. At this time, the current, the solenoid valve opening, and the compressor speed are all at the maximum. 3 <k 2 +0.7≤T sh When k is reached, the control module 10 controls to gradually reduce the current of the semiconductor refrigerator 3 and the opening of the first solenoid valve 8 until the power is cut off and closed; if k cannot be reached, 3 <k 2 +0.7≤T sh Logical relationship, feedback signal to control module 10, readjust current and opening until temperature relationship is satisfied;

[0049] 7) When (k 2 +k 3 ) / 2<T sl When , it means that the temperature of battery cell 4 is gradually decreasing, and the system enters the heating mode;

[0050] 8) When T sl-1 <(k 2 +k 3 ) / 2<T sl When the heat flux density in the PCM phase change material 2 is monitored, when w 1When it is stable, it means that the phase change has been completed. The heat flux density sensor q1, the second temperature sensor T2 and the third temperature sensor T3 feed back the temperature signal and the heat flux signal to the control module 10, and control the semiconductor refrigerator 3 or the refrigerant pipeline 6 to heat the system separately; when the semiconductor refrigerator 3 is started and the refrigerant pipeline 6 is closed, the control module 10 controls the current of the semiconductor refrigerator 3 to change direction, and adjusts the input current to gradually increase. When k 1 When the set temperature of the temperature plate is reached, the first temperature sensor T1 transmits the temperature signal to the control module 10, controls the current of the semiconductor refrigerator 3 to be stable, and scans the temperature every 5 seconds to determine the logical relationship between the temperatures until k is determined. 3 <k 2 +0.7, the control module 10 controls the semiconductor refrigerator 3 to increase the input current to continue heating, and the temperature is scanned every 1s to ensure that the temperature of the battery cell 4 meets k 3 <k 2 +0.7, if the temperature logic relationship of the battery cell 4 is not established, the semiconductor refrigerator 3 maintains the current stable input, repeats several times and scans the temperature every 5s to determine the logical relationship between the temperatures. 1 <(k 2 +k 3 ) / 2+0.7 and T sl ≤(k 2 +k 3 ) / 2≤T sh When the temperature is 0.0400 W, it indicates that the system is working in the normal temperature zone, and the temperature signal is fed back to the control module 10, which controls the current of the semiconductor refrigerator 3 to decrease until the power is cut off; when the semiconductor refrigerator 3 is turned off and the refrigerant pipeline 6 is turned on, the control module 10 controls the refrigerant flow direction in the four-way reversing valve 13 in the air-conditioning system, and the refrigerant flows in from the second solenoid valve 9. At the same time, the second solenoid valve 9 turns on the throttling function, and gradually increases the opening degree f of the second solenoid valve 9. 2 , scan the temperature every 2s, when k 3 >k 2 +0.7, the second temperature sensor T2 and the third temperature sensor T3 feed back the temperature signal to the control module 10, control the air conditioning system compressor 14 to increase the speed, the refrigerant pipe 6 releases more heat, and continues to heat up. The heating scans the temperature every 1s to ensure that the temperature of the battery cell 4 is k 3 <k 2 +0.7, if the logical relationship is not established, keep the current compressor speed stable input, repeat several times and scan the temperature every 5s. 1 <(k 2 +k 3 ) / 2+0.7 and T sl ≤(k 2 +k 3) / 2≤T sh When , it indicates that the system is working in the normal temperature zone, and the temperature signal is fed back to the control module, which controls the speed of the compressor 14 to decrease until the power is cut off;

[0051] 9) Similarly, when t e With t r Satisfy t e >t 1 or r >t 2 Logical relationship, and at this time the temperature satisfies the logical relationship T sl-1 <(k 2 +k 3 ) / 2<T sl , the temperature and time signals are fed back to the control module 10 to control the semiconductor refrigerator 3 or the refrigerant pipeline 6 to heat simultaneously;

[0052] 10) When T sl-2 <(k 2 +k 3 ) / 2≤T sl-1 When the system temperature drops further, more heat is needed to maintain the system operation. At this time, the temperature signal is fed back to the control module to control the speed of the compressor 14 and the opening of the second solenoid valve 9 to be in the maximum mode. The temperature is raised based on the heat generated by the refrigerant pipeline. The control module scans k every 5 seconds. 2 and k 3 , when (k 2 +k 3 ) / 2>T sl-1 +5, the input current of semiconductor cooler 3 gradually increases, and scans k every 2s 1 , k 2 and k 3 Logical relationship, when k is satisfied 1 <(k 2 +k 3 ) / 2+0.7 and T sl ≤(k 2 +k 3 ) / 2≤T sh When , it means that the system is maintained in the normal temperature zone and the temperature uniformity is good, and the temperature signal is fed back to the control module 10 to control the compressor speed and the current of the semiconductor refrigerator 3 to decrease until the power is cut off;

[0053] 11) When (k 2 +k 3 ) / 2≤T sl-2When the system is in an extremely low temperature environment, the battery performance is limited, the semiconductor refrigerator 3 and the refrigerant pipeline 6 heat the system at the same time, and at this time the second solenoid valve 9 is opened to the maximum, the compressor 14 has the maximum speed, the semiconductor refrigerator 3 has the maximum input current but the maximum is Imax under the maximum cooling condition, and the control module scans k every 5s 2 and k 3 , when (k 2 +k 3 ) / 2>T sl-2 +5, the control module 10 controls the semiconductor refrigerator 3 to turn off for a period of time, when (k 2 +k 3 ) / 2>T sl-1 When k 1 , k 2 and k 3 Logical relationship, when k 1 <(k 2 +k 3 ) / 2+0.7, it indicates that the system has good temperature uniformity in the current state. The control module 10 controls the input current of the semiconductor refrigerator 3 to gradually increase. At this time, the heat provided gradually increases. The control module scans k every 5 seconds. 2 and k 3 , when (k 2 +k 3 ) / 2>T sl-1 +5, indicating that the system temperature is gradually approaching the appropriate temperature zone. At this time, the compressor 14 is controlled to be turned off, the refrigerant pipeline 6 stops working, the input current of the semiconductor refrigerator 3 is kept unchanged, and the control module scans the temperature every 2s. 1 <(k 2 +k 3 ) / 2+0.7, gradually reduce the input current of semiconductor refrigerator 3 until (k 2 +k 3 ) / 2≥T sl And at this time k 3 <k 2 +0.7, indicating that the system is in an appropriate temperature zone and the temperature uniformity is good. The control module 10 receives the temperature signal and controls the semiconductor refrigerator 3 to cut off the power.

[0054] Compared with the prior art, the control method of the battery thermal management system of the utility model can implement temperature zoning thermal management by feedback adjusting the switch of the semiconductor refrigerator, the size and direction of the input current, the switch of the solenoid valve in the inlet and outlet of the refrigerant pipeline and the switch and speed of the compressor through the upper and lower surface temperatures of the battery cell, the inner surface temperature of the shell, and the heat flux density of the PCM phase change material. When the battery cell temperature is greater than the low temperature rated setting temperature and less than the high temperature rated setting temperature, the system is in automatic adjustment mode. When it is higher than the high temperature rated setting temperature, the system enters the cooling mode. When it is lower than the low temperature rated setting temperature, the system enters the heating mode. When the temperature difference reaches the set value, heat dissipation and heating treatment can be carried out, which ensures the temperature uniformity of the battery module and reduces the risk of temperature gradient in the battery. The utility model uses the time signal detected by the timer and the temperature signal detected by the temperature sensor to jointly feedback whether the controller controls the semiconductor refrigerator and the refrigerant pipeline to work together, and autonomously judges and feedbacks the adjustment, making heat dissipation and temperature control more convenient, avoiding long-term work but difficult heat dissipation / heating, achieving precise temperature control and saving costs.

[0055] To sum up, the battery thermal management system proposed in the utility model improves the efficiency and stability of the thermal management system by combining passive thermal management with active thermal management; realizes zoned precise temperature control through different control methods to achieve efficient and stable operation in all seasons and all working conditions; heat dissipation and heating treatment can only be carried out when the temperature difference reaches the set value, ensuring the uniformity of the battery module temperature and reducing the risk of temperature gradients; autonomous judgment combined with feedback adjustment makes temperature control more convenient, avoids long-term operation without difficulty in heat dissipation / heating, and saves system costs while accurately controlling the temperature.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present application, the present technical solution can also be subjected to a number of simple modifications and replacements, and these modifications and replacements also fall within the scope of protection covered by the claims.

Claims

1. A battery thermal management system, characterized in that: It comprises a battery module, a control module (10), a timer (11), an air conditioning system heat exchanger (12), a four-way reversing valve (13) and a compressor (14); The battery module comprises a shell (1), a semiconductor refrigerator (3) is arranged on the outer surface of the shell (1), a refrigerant pipeline (6) is arranged around the inside of the shell (1), a refrigerant flows in the refrigerant pipeline (6), a plurality of battery cells (4) are arranged inside the area surrounded by the refrigerant pipeline (6), the battery cells (4) are all sleeved in a heat conduction pipe (5) with fins, and the gap inside the shell (1) is filled with PCM phase change material (2); a first temperature sensor (T1) is arranged on the inner surface of the shell (1) A second temperature sensor (T2) and a third temperature sensor (T3) are respectively arranged on the upper and lower surfaces of the battery cell (4), and a heat flux density sensor (q1) is distributed in the PCM phase change material (2); a first solenoid valve (8) and a second solenoid valve (9) are respectively arranged at the inlet and outlet of the refrigerant pipeline (6), the first solenoid valve (8) is connected to the air conditioning system heat exchanger (12), and the air conditioning system heat exchanger (12) is connected to the compressor (14) and the second solenoid valve (9) through a four-way reversing valve (13); The timer (11) is connected to the semiconductor refrigerator (3) and the first solenoid valve (8) and the second solenoid valve (9), and the timer (11) detects the time for the semiconductor refrigerator (3) or the refrigerant pipeline (6) to dissipate heat or heat the battery core (4) alone; The semiconductor refrigerator (3), the first solenoid valve (8), the second solenoid valve (9), the timer (11), the four-way reversing valve (13), the compressor (14), the first temperature sensor (T1), the second temperature sensor (T2), the third temperature sensor (T3) and the heat flux density sensor (q1) are all connected to the control module (10); the control module (10) controls the current magnitude and direction of the semiconductor refrigerator (3), the openings of the first solenoid valve (8) and the second solenoid valve (9), the direction of the four-way reversing valve (13) and the speed of the compressor (14) according to the temperature feedback signals of the first temperature sensor (T1), the second temperature sensor (T2) and the third temperature sensor (T3), the heat flux feedback signal of the heat flux density sensor (q1) and the time feedback signal of the timer (11).

2. The battery thermal management system according to claim 1, characterized in that: The inner wall of the refrigerant pipeline (6) is provided with an internal thread for circulating refrigerant, and the outer wall of the refrigerant pipeline (6) is provided with fins; the refrigerant pipeline (6) is arranged in a coil-like manner around the interior of the shell (1); phase change material is distributed along the refrigerant pipeline (6) to achieve integrated energy storage and heat exchange; the battery thermal management system is coupled and interacted with the air conditioning system through the refrigerant pipeline (6); the refrigerant flow direction is changed by the four-way reversing valve (13) to achieve the refrigerant pipeline (6) to store cold or heat in the battery module.

3. The battery thermal management system according to claim 1, characterized in that: The semiconductor refrigerator (3) is any one of a single-stage semiconductor cooling plate, a double-stage semiconductor cooling plate or a multi-stage semiconductor cooling plate; The cold end surface of the semiconductor refrigerator (3) is attached to the outer surface of the shell (1) through a flexible heat-conducting material, and the hot end surface is connected to a hot end radiator through a flexible heat-conducting material. The hot end radiator has a refrigerant outlet and an inlet, and refrigerant flows inside. The semiconductor refrigerator (3) can realize the mutual switching between the cold end face and the hot end face by changing the direction of the current.

4. The battery thermal management system according to claim 1, characterized in that: The inner surface of the housing (1) is provided with a 3D temperature averaging plate (7), and the first temperature sensor (T1) is provided on the inner surface of the 3D temperature averaging plate (7); The shell (1) is in the shape of a regular hexagonal prism, the outer surface of the shell (1) is attached to the semiconductor refrigerator (3) via a flexible heat-conducting material, and the inner surface of the shell (1) is attached to the 3D temperature-averaging plate (7) via a flexible heat-conducting material.

5. The battery thermal management system according to claim 1, characterized in that: The interior of the heat-conducting tube (5) with fins is closely connected to the battery core (4) via a flexible heat-conducting material.

6. The battery thermal management system according to any one of claims 3 to 5, characterized in that: The flexible heat-conducting material is any one of heat-conducting silicone grease, heat-conducting pad, heat-conducting rubber and metal film.

7. The battery thermal management system according to claim 1, characterized in that: The shell (1) is made of any one of copper, stainless steel, aluminum and aluminum alloy.

8. The battery thermal management system according to claim 1, characterized in that: The surface fins of the heat conducting pipe (5) are composed of a combination of conical fins (51), corrugated fins (52) and rectangular fins (53); the rectangular fins (53) and the conical fins (51) are distributed in two areas, and the corrugated fins (52) are arranged between two adjacent fins.

9. The battery thermal management system according to claim 1, characterized in that: The PCM phase change material (2) is any one of n-dodecane, calcium chloride hexahydrate, paraffin, a mixture of paraffin and graphene, and phase change microcapsules.

10. The battery thermal management system according to claim 1, characterized in that: The compressor adopts a variable frequency compressor, which can automatically adjust the speed according to demand, and then adjust the temperature of the refrigerant pipeline.

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