Immersed battery pack thermal management system and thermal management method

Abstract

The immersed battery pack thermal management system comprises a battery pack box body, the battery pack box body is provided with a containing cavity with an opening in the top, the containing cavity is filled with a cooling medium, and a liquid outlet is formed in the side wall of the bottom of the battery pack box body; the plurality of single batteries are arranged in the accommodating chamber and are immersed in the cooling medium; the phase change working medium is arranged in the accommodating chamber and surrounds the outer side of the single battery; the cooling box body is fixedly arranged at the top opening of the battery pack box body, the bottom surface of the cooling box body is provided with a communication port communicated with the accommodating cavity, and a liquid inlet is formed in the cooling box body; by combining static cooling, low-flow dynamic cooling, high-flow dynamic cooling and multi-layer thermal management of the phase-change material, the cooling strategy can be dynamically adjusted under different temperature conditions, efficient heat dissipation is ensured, the internal temperature of the battery pack is more uniform by using the phase-change working medium, a proper cooling mode is selected as required, and the cooling efficiency is improved. And unnecessary energy consumption is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and in particular to a thermal management system and a thermal management method for an immersed battery pack. Background Art

[0002] With the development of the new energy vehicle industry, the performance of power batteries also has an important impact on the market share of new energy vehicles. New energy vehicles have put forward higher requirements for the safety, reliability and driving range of power batteries, which requires the thermal management system of power batteries to be safer and more reliable. The commonly used cooling method for the thermal management system of power batteries is to achieve heat exchange through a liquid cooling plate structure. This cooling method has a long heat transfer path, large thermal resistance, low heat exchange efficiency, and relatively high weight and processing costs.

[0003] As a new cooling method, immersion cooling battery directly fills the cooling medium in the battery pack box and completely immerses the single battery in the cooling medium for heat exchange cooling. Traditional immersion cooling methods cannot have both high heat dissipation efficiency and high temperature balance. Among them, immersion cooling has dynamic immersion and static immersion. Dynamic immersion is to remove the heat of the battery by circulating coolant into the battery pack box. Static immersion is that the coolant is in a closed battery pack box and relies on the coolant to absorb the heat of the battery. These two methods have certain defects. Among them, although the dynamic immersion cooling method can dissipate heat efficiently, it is difficult to maintain the temperature uniformity of the battery pack, and its energy consumption is relatively high; although the static immersion cooling method can maintain the temperature uniformity of the battery pack and does not consume any energy, its heat dissipation efficiency is very poor. Summary of the invention

[0004] In view of this, the present invention proposes an immersion type battery pack thermal management system and a thermal management method to solve the problems of low battery heat dissipation performance and thermal balance and high energy consumption in traditional immersion type thermal management systems.

[0005] The technical solution of the present invention is achieved in this way:

[0006] In a first aspect, the present invention provides an immersed battery pack thermal management system, comprising:

[0007] A battery pack box body, which has a accommodating chamber with an open top, the interior of the accommodating chamber is filled with a cooling medium, and a liquid outlet is opened on the bottom side wall of the battery pack box body;

[0008] A plurality of single cells are disposed in the accommodating chamber and immersed in a cooling medium;

[0009] The phase change working medium is arranged in the accommodating chamber and surrounds the outer side of the single battery;

[0010] The cooling box is fixedly arranged at the top opening of the battery pack box, and the bottom surface of the cooling box has a connecting port connected to the accommodating chamber. The cooling box is provided with a liquid inlet, and the liquid inlet and the liquid outlet are both provided with electromagnetic flow valves;

[0011] The control system includes a first temperature sensor, a second temperature sensor and a controller. The first temperature sensor is arranged inside a battery pack case and is used to detect the temperature of a single cell. The second temperature sensor is used to detect the temperature of a coolant in the battery pack case. The first temperature sensor, the second temperature sensor and the electromagnetic flow valve are electrically connected to the controller respectively.

[0012] On the basis of the above technical solution, preferably, a first partition and a second partition are fixedly arranged in the upper and lower parts of the accommodating chamber, and the first partition divides the accommodating chamber from top to bottom into a first chamber, a second chamber and a third chamber;

[0013] The cooling box is fixedly arranged in the first chamber, the communication port is communicated with the first chamber, and the liquid outlet is communicated with the third chamber;

[0014] A plurality of sleeves are vertically fixed between the first partition and the second partition, and two ends of the sleeves extend out of the first partition and the second partition respectively;

[0015] The single cell is vertically fixed in the sleeve, and a flow channel is provided between the single cell and the sleeve, the flow channel connects the first chamber and the third chamber, and the phase change medium is provided in the second chamber.

[0016] On the basis of the above technical solution, preferably, the phase change working medium includes a solid granular phase change material filled in the second chamber.

[0017] Further, preferably, the phase change working fluid also includes a coating layer, the coating layer is filled with the solid granular phase change material, the outer wall of the sleeve is provided with a plurality of first liquid permeable holes, and the second chamber and the flow channel are connected through the first liquid permeable holes.

[0018] Furthermore, preferably, a plurality of second liquid-permeable holes are provided on the second partition plate, and the second chamber and the third chamber are connected through the second liquid-permeable holes.

[0019] On the basis of the above technical solution, preferably, a plurality of single cells are arranged vertically to form a plurality of battery packs, a cooling box is fixedly provided in the first chamber where the upper end of each battery pack is located, a plurality of connecting ports are provided on the bottom surface of the cooling box, and the plurality of connecting ports correspond one by one to the plurality of single cells in the battery pack.

[0020] Further, preferably, the connecting port is a circular hole structure, a guide plate with a circular structure is coaxially arranged in the connecting port, an annular flow channel is provided between the guide plate and the connecting port, a connecting rod is fixedly provided on the top surface of the guide plate and the top surface of the inner cavity of the cooling box, and the annular flow channel corresponds to the position of the flow channel.

[0021] As some embodiments, the bottom surface of the cooling box body contacts the top surface of the first partition.

[0022] As another embodiment, a gap is provided between the bottom surface of the cooling box body and the top surface of the first partition, and a plurality of third liquid permeable holes communicating with the second chamber are provided on the first partition.

[0023] In a second aspect, the present invention discloses a method for thermal management of an immersed battery pack, which utilizes the thermal management system of the immersed battery pack described in the first aspect, and includes the following steps:

[0024] S1. When the first temperature sensor measures that the temperature of the single cell is lower than 40°C, the electromagnetic flow valves on the liquid inlet and the liquid outlet are in a closed state, and the static coolant in the sleeve and the phase-changing working fluid outside the sleeve cooperate to achieve heat dissipation of the single cell;

[0025] S2. When the first temperature sensor measures that the temperature of the single cell is higher than 40°C, and the second temperature sensor measures that the temperature of the coolant is lower than 35°C, the controller controls the electromagnetic flow valves on the liquid inlet and the liquid outlet to open slightly, and circulates the coolant into the battery pack at a low flow rate. The coolant flows through the surface of the single cell to take away the heat, and the phase change working fluid absorbs the heat in the coolant, assisting the thermal management system to achieve active and passive synchronous heat dissipation;

[0026] S3. When the second temperature sensor measures that the coolant temperature is higher than 35°C, the phase change material is basically completely melted. The controller controls the electromagnetic flow valves on the liquid inlet and outlet to be fully opened, and circulates the coolant into the battery pack body at a high flow rate. The cooling method of the battery thermal management system is converted to active cooling of pouring immersion liquid cooling.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention achieves the following technical effects by combining static cooling, low-flow dynamic cooling, high-flow dynamic cooling and multi-level thermal management of phase change materials: 1. Dynamically adjust the cooling strategy under different temperature conditions to ensure efficient heat dissipation. 2. The use of phase change fluid makes the temperature inside the battery pack more uniform and avoids local overheating. 3. Select the appropriate cooling mode as needed to avoid unnecessary energy consumption, especially under low temperature conditions, through static cooling and passive heat dissipation of phase change fluid to save energy. 4. The combination of multiple cooling methods improves the overall reliability and flexibility of the system and adapts to different working environments and needs.

[0029] (2) By providing the first liquid permeable hole, the second chamber and the flow channel are connected, so that the coolant not only circulates in the flow channel, but also partially enters the second chamber to directly contact the phase change material. The heat exchange between the phase change material and the coolant is more direct and efficient, the heat exchange area is larger, and the coolant can transfer heat to the phase change material more quickly, accelerating its phase change process from solid to liquid. At the same time, the heat transfer path from the single battery to the phase change material is shortened, so that the phase change material can absorb heat more quickly and achieve phase change.

[0030] (3) The coating layer encapsulates the phase change material inside. When the phase change material changes from solid to liquid, the coating layer can effectively prevent it from flowing out, and further prevent it from flowing out through the first liquid permeable hole after melting, thereby ensuring the integrity of the phase change material and the stability of the system.

[0031] (4) Since each cooling box corresponds to a battery pack, the coolant can flow directly from the cooling box downward to each single battery, thereby avoiding the problem of uneven distribution of the coolant during the flow process.

[0032] (5) By setting an annular flow channel at the connecting port, most of the coolant flowing out of the annular flow channel can enter the flow channel between the sleeve and the single battery. The coolant flows downward along the flow channel, which can reduce the direct impact of the coolant on the top surface of the single battery and avoid physical damage to the battery caused by long-term high-flow impact.

[0033] (6) A gap is provided between the bottom surface of the cooling box and the top surface of the first partition, and a plurality of third liquid permeable holes connected to the second chamber are provided on the first partition. Thus, a large flow of coolant can have multiple flow paths, thereby reducing flow resistance and improving the heat dissipation efficiency of the single cell. At the same time, the phase change material is accelerated to change from liquid to solid, thereby providing continuous thermal management performance for the single cell in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is an exploded schematic diagram of the submerged battery pack thermal management system disclosed in the present invention;

[0036] Figure 2 It is a schematic diagram of the internal structure of the submerged battery pack thermal management system disclosed in the present invention;

[0037] Figure 3 A top view of the submerged battery pack thermal management system disclosed in the present invention;

[0038] Figure 4 for Figure 3 Plane section view at AA in the middle;

[0039] Reference numerals:

[0040] 1. Battery pack box; 10. Accommodating chamber; 101. First chamber; 102. Second chamber; 103. Third chamber; 2. Single cell; 3. Phase change medium; 4. Cooling box; 41. Connecting port; 42. Liquid inlet; 11. Liquid outlet; 5. Control system; 51. First temperature sensor; 52. Second temperature sensor; 53. Controller; 6. First partition; 7. Second partition; 8. Cylinder sleeve; 81. Flow channel; 31. Phase change material; 32. Coating layer; 82. First liquid permeable hole; 71. Second liquid permeable hole; 20. Battery pack; 43. Drain plate; 44. Annular flow channel; 45. Connecting rod; 61. Third liquid permeable hole. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] like Figure 1 As shown, combined Figure 2-4 An embodiment of the present invention discloses an immersion battery pack thermal management system, including a battery pack box 1, a plurality of single cells 2, a phase change working fluid 3, a cooling box 4 and a control system 5.

[0043] The battery pack box 1 has a top-opened accommodating chamber 10, which is filled with a cooling medium. The cooling medium filled in the accommodating chamber 10 is a cooling liquid made of insulating material, which is used to immerse the single battery 2.

[0044] A plurality of single cells 2 are disposed in the accommodating chamber 10 and immersed in the cooling medium, and a preliminary heat exchange is achieved through the cooling medium.

[0045] The phase change medium 3 is arranged in the accommodating chamber 10 and surrounds the outer side of the single battery 2. The phase change medium 3 has the characteristics of absorbing and releasing heat. It can adjust the temperature through phase change (solid to liquid or liquid to solid) when the temperature changes, providing additional thermal management performance.

[0046] The cooling box 4 is fixedly arranged at the top opening of the battery pack box 1, and the cooling box 4 seals the top opening end of the battery pack box 1. The bottom surface of the cooling box 4 has a connecting port 41 connected to the accommodating chamber 10, and a liquid inlet 42 is provided on the cooling box 4. The bottom side wall of the battery pack box 1 is provided with a liquid outlet 11. The liquid inlet 42 and the liquid outlet 11 are both provided with an electromagnetic flow valve (not shown in the figure). The electromagnetic flow valve is used to control the opening and closing of the liquid inlet 42 and the liquid outlet 11, so as to control whether the cooling medium flows in the entire battery pack under different working conditions, and can also control the flow rate of the coolant.

[0047] The control system 5 includes a first temperature sensor 51, a second temperature sensor 52 and a controller 53. The first temperature sensor 51 is arranged on the surface of the battery cell and is used to detect the temperature of the single cell 2. The second temperature sensor 52 is used to detect the temperature of the coolant in the battery pack box 1. The first temperature sensor 51, the second temperature sensor 52 and the electromagnetic flow valve are electrically connected to the controller 53 respectively, and the opening and closing of the electromagnetic flow valve and the flow of the coolant are controlled by the data of the temperature sensor.

[0048] When the temperature of the single battery 2 is lower than 40°C, the system adopts static cooling mode, the electromagnetic flow valve is closed, and the coolant does not flow. At this time, the heat is mainly dissipated through the synergistic effect of the static coolant and the phase change medium 3. The phase change medium 3 absorbs heat and undergoes phase change, balancing the temperature and improving the temperature balance without consuming additional energy.

[0049] When the temperature of the single battery 2 is higher than 40°C and the temperature of the coolant is lower than 35°C, the controller 53 controls the electromagnetic flow valve to open slightly, and the coolant circulates at a low flow rate. The coolant flows through the surface of the single battery 2 and takes away some heat, and the phase change working fluid 3 continues to absorb heat to provide auxiliary heat dissipation. In this mode, the system realizes active and passive synchronous heat dissipation to keep the battery temperature balanced.

[0050] When the coolant temperature is higher than 35°C and the phase change material 31 is almost completely melted, the controller 53 controls the electromagnetic flow valve to be fully opened, the coolant circulates at a high flow rate, and the system is converted into an active cooling mode. At this time, a large amount of heat is effectively removed through the rapid circulation of the high-flow coolant to prevent the battery from overheating.

[0051] The present invention achieves the following technical effects by combining static cooling, low-flow dynamic cooling, high-flow dynamic cooling and multi-level thermal management of phase change material 31: 1. Dynamically adjust the cooling strategy under different temperature conditions to ensure efficient heat dissipation. 2. The use of phase change working fluid 3 makes the internal temperature of the battery pack 20 more uniform to avoid local overheating. 3. Select the appropriate cooling mode as needed to avoid unnecessary energy consumption, especially under low temperature conditions through static cooling and passive heat dissipation of phase change working fluid 3 to save energy. 4. The combination of multiple cooling methods improves the overall reliability and flexibility of the system and adapts to different working environments and needs.

[0052] The present invention further optimizes the thermal management system of the immersed battery pack and also provides the following technical solutions.

[0053] In this embodiment, a first partition plate 6 and a second partition plate 7 are fixedly arranged in the upper and lower parts of the accommodating chamber 10. The first partition plate 6 divides the accommodating chamber 10 from top to bottom into a first chamber 101, a second chamber 102 and a third chamber 103. The first chamber 101 is located at the uppermost layer and is used to install the cooling box 4. The second chamber 102 is located at the middle layer and is used to place the phase change working medium 3. The third chamber 103 is located at the lowermost layer and is used to communicate with the outlet 11 of the coolant.

[0054] The cooling box body 4 is fixedly arranged in the first chamber 101, the connecting port 41 is connected to the first chamber 101, the liquid outlet 11 is connected to the third chamber 103, and a plurality of sleeves 8 are vertically fixedly arranged between the first partition 6 and the second partition 7, and the two ends of the sleeves 8 extend out of the outside of the first partition 6 and the second partition 7 respectively. Thus, a flow path for the coolant is formed between the first chamber 101, the sleeves 8 and the third chamber 103.

[0055] The single cell 2 is vertically fixed in the sleeve 8, and a flow channel 81 is provided between the single cell 2 and the sleeve 8. The flow channel 81 connects the first chamber 101 and the third chamber 103 to form a flow path for the coolant from the first chamber 101 to the third chamber 103. The phase change medium 3 is provided in the second chamber 102. The phase change medium 3 adjusts the temperature inside the battery pack by absorbing and releasing heat.

[0056] The design of the sleeve 8 and the flow channel 81 enables the coolant to communicate between the third chamber 103 and the flow channel 81, so that the coolant can efficiently flow through the surface of each single battery 2 and take away the heat. This structure not only increases the flow path of the coolant, but also increases the contact area between the coolant and the single battery 2, thereby enhancing the heat dissipation effect.

[0057] The phase change medium 3 is centrally arranged in the second chamber 102, which can better manage and distribute heat. The phase change medium 3 undergoes phase change when absorbing the heat of the battery, providing stable temperature control.

[0058] It is worth noting that in the initial state, the coolant fills the battery pack box 1 and the cooling box 4, so the single battery 2 is immersed in the coolant. At the same time, since each single battery 2 is respectively arranged in the sleeve 8, the flow channel 81 of the annular structure formed between the sleeve 8 and the single battery 2 provides an independent cooling space for the single battery 2, ensuring that the coolant in each space dissipates heat for the single battery 2 separately, making the temperature distribution in each space more uniform, thereby ensuring that all single batteries 2 have higher temperature uniformity.

[0059] As an embodiment, the phase change medium 3 includes a solid granular phase change material 31 filled in the second chamber 102. In this case, the second chamber 102 is a closed chamber, which is formed by the first partition 6, the second partition 7, the sleeve 8 and the side wall of the battery pack body 1. The solid granular phase change material 31 is filled in the second chamber 102. When the heat released by the single cell 2 is absorbed by the coolant on the one hand, on the other hand, the heat in the coolant is transferred to the phase change material 31 filled in the second chamber 102 through the sleeve 8, so that the phase change material 31 absorbs heat and changes from solid to liquid, thereby providing additional heat exchange effect for the single cell 2.

[0060] Since the second chamber 102 has a certain space, the solid granular phase change material 31 filled in the second chamber 102 gradually absorbs heat and melts from the side close to the sleeve 8 when absorbing heat. The heat transfer path is long and the heat absorption efficiency of the phase change medium 3 cannot be effectively improved.

[0061] To this end, the present embodiment provides a structural arrangement for the phase change medium 3. Specifically, the phase change medium 3 also includes a coating layer 32 filled with a phase change material 31. The outer wall of the sleeve 8 is provided with a plurality of first liquid permeable holes 82. The second chamber 102 and the flow channel 81 are connected via the first liquid permeable holes 82.

[0062] By setting the first liquid permeable hole 82, the second chamber 102 and the flow channel 81 are connected, so that the coolant not only circulates in the flow channel 81, but also partially enters the second chamber 102 and directly contacts the phase change material 31. The heat exchange between the phase change material 31 and the coolant is more direct and efficient, and the heat exchange area is larger. The coolant can transfer heat to the phase change material 31 more quickly, accelerating its phase change process from solid to liquid. At the same time, the heat transfer path from the single battery 2 to the phase change material 31 is shortened, so that the phase change material 31 can absorb heat more quickly and achieve phase change.

[0063] The coating layer 32 encapsulates the phase change material 31 inside. When the phase change material 31 changes from solid to liquid, the coating layer 32 can effectively prevent it from flowing out, and further prevent it from flowing out through the first liquid permeable hole 82 after melting, thereby ensuring the integrity of the phase change material 31 and the stability of the system.

[0064] When the coolant enters the second chamber 102 through the flow channel 81 and the first liquid permeable hole 82, although the contact area between the coolant and the phase change material 31 can be increased to improve the heat exchange efficiency, the coolant needs to flow back and then flow out of the first liquid permeable hole 82 after entering the second chamber 102. This process will cause fluid flow resistance in the second chamber 102, which will reduce the flow efficiency of the coolant and affect the overall heat exchange effect. At the same time, it will cause the coolant to reflux poorly in the second chamber 102, resulting in the coolant being retained and unable to effectively participate in the heat exchange, resulting in reduced heat exchange efficiency and possibly uneven temperature.

[0065] To this end, a plurality of second liquid permeable holes 71 are provided on the second partition plate 7, and the second chamber 102 and the third chamber 103 are connected through the second liquid permeable holes 71. Thus, the second liquid permeable holes 71 on the second partition plate 7 provide an additional circulation channel, so that the coolant can flow downward from the second chamber 102 into the third chamber 103, reducing the reflux path of the coolant in the second chamber 102 and reducing the flow resistance. After the coolant flows into the third chamber 103 through the second liquid permeable holes 71, it can continue to flow, avoiding retention in the second chamber 102, ensuring that the coolant can continue to participate in the heat exchange process and maintain the temperature balance of the system.

[0066] As some preferred embodiments, multiple single cells 2 are arranged vertically to form a number of battery groups 20, and a cooling box 4 is fixedly installed in the first chamber 101 where the upper end of each battery group 20 is located, and multiple connecting ports 41 are arranged on the bottom surface of the cooling box 4, and the multiple connecting ports 41 correspond one by one to the multiple single cells 2 in the battery group 20.

[0067] By adopting the above technical solution, each cooling box 4 corresponds to a battery pack 20, and the coolant can flow directly downward from the cooling box 4 to each single battery 2, avoiding the problem of uneven distribution of the coolant during the flow process.

[0068] In this embodiment, the single cell 2 is vertically arranged in the tube sleeve 8, and the connecting port 41 is located directly above the single cell 2. When the coolant flows from top to bottom in the cooling box, it will directly impact the top of the single cell 2. Especially when the coolant flow rate is large, the coolant impact will cause damage to the single cell 2 under a long-term working environment.

[0069] To this end, in this embodiment, the connecting port 41 is set as a circular hole structure, and a guide plate 43 of a circular structure is coaxially arranged in the connecting port 41. An annular flow channel 44 is provided between the guide plate 43 and the connecting port 41. A connecting rod 45 is fixedly provided on the top surface of the guide plate 43 and the top surface of the inner cavity of the cooling box 4. The connecting rod 45 ensures that the guide plate 43 can be stably arranged in the connecting port 41. With this arrangement, the coolant flows downward through the annular flow channel 44, which can reduce the area of ​​the coolant impacting the top surface of the single battery 2, so that the coolant presents an annular flow state. The annular flow channel 44 corresponds to the position of the flow channel. With this arrangement, most of the coolant flowing out through the annular flow channel 44 can enter the flow channel 81 between the sleeve 8 and the single battery 2. The coolant flows downward along the flow channel 81, which can reduce the direct impact of the coolant on the top surface of the single battery 2 and avoid physical damage to the battery caused by long-term high flow impact.

[0070] In addition, after the coolant flows out along the annular flow channel 44 , it enters the flow channel 81 between the sleeve 8 and the single battery 2 , ensuring that the coolant is evenly distributed around the single battery 2 .

[0071] As an implementation mode, the bottom surface of the cooling box 4 contacts the top surface of the first partition 6. With this configuration, the coolant can enter the flow channel 81 more directly and quickly, reducing the flow resistance and time delay, and improving the flow efficiency of the coolant. At the same time, each cooling box 4 corresponds to a battery pack 20, and the coolant in each cooling box 4 cools its own single battery 2. The independent cooling path ensures that the coolant flow path of each battery pack 20 is uniform and efficient, avoiding the reduction in efficiency caused by the coolant being diverted between multiple battery packs 20. This independent cooling method helps to balance the temperature of each battery pack 20, avoid local overheating or insufficient cooling, thereby extending the battery life and improving system safety.

[0072] When the battery is working in the static coolant, the coolant temperature is high and the phase change material 31 is completely melted. At this time, a large flow of coolant needs to be added to the cooling box 4 to implement active cooling when pouring the single battery 2, so that the heat released by the single battery 2 can be quickly taken away by the large flow of coolant.

[0073] In the above embodiment, if a large flow of coolant is introduced into the cooling box 4, the coolant flows from the annular flow channel 44 to the flow channel 81. When the bottom surface of the cooling box 4 contacts the top surface of the first partition 6, the flow path of the coolant can only enter the flow channel 81 through the annular flow channel 44. The cross-sectional area of ​​the channel for the flow of the coolant is small, which will cause the flow resistance to increase and the flow rate to slow down. At the same time, the phase change material 31 cannot quickly change from liquid to solid.

[0074] To this end, in this embodiment, a space is provided between the bottom surface of the cooling box body 4 and the top surface of the first partition plate 6 , and a plurality of third liquid permeable holes 61 communicating with the second chamber 102 are provided on the first partition plate 6 .

[0075] With this structural setting, after the coolant flows downward from the annular flow channel 44, when the coolant flow rate is large, a part of the coolant will flow downward along the flow channel 81, and the other part of the coolant will flow into the first chamber 101, and enter the second chamber 102 through the third liquid permeable hole 61 on the first partition 6, thereby directly contacting the phase change material 31, accelerating the process of its transformation from liquid to solid. At the same time, after the coolant enters the second chamber 102, it can also enter the flow channel 81 through the first liquid permeable hole 82 to achieve heat dissipation for the single battery 2. Through the setting of the third liquid permeable hole 61, the large-flow coolant can have multiple flow paths, which reduces the flow resistance and improves the heat dissipation efficiency of the single battery 2. At the same time, it accelerates the transformation of the phase change material 31 from liquid to solid, thereby providing continuous thermal management performance for the single battery 2 in the future.

[0076] The present invention also discloses a thermal management method for an immersed battery pack, comprising the following steps:

[0077] S1. When the first temperature sensor 51 measures that the temperature of the single cell 2 is lower than 40°C, the electromagnetic flow valves on the liquid inlet 42 and the liquid outlet 11 are in a closed state, and the static coolant in the sleeve and the phase-changing working medium 3 outside the sleeve cooperate to achieve heat dissipation of the single cell 2;

[0078] S2, when the first temperature sensor 51 measures that the temperature of the single battery 2 is higher than 40°C, and the second temperature sensor 52 measures that the temperature of the coolant is lower than 35°C, the controller 53 controls the electromagnetic flow valves on the liquid inlet 42 and the liquid outlet 11 to be slightly opened, and circulates the coolant into the battery pack box 1 at a low flow rate, and the coolant flows through the surface of the single battery 2 to take away the heat, and at the same time the phase change working fluid 3 absorbs the heat in the coolant, and the auxiliary thermal management system realizes active and passive synchronous heat dissipation;

[0079] S3. When the second temperature sensor 52 measures that the coolant temperature is higher than 35°C, the phase change material 31 is basically completely melted. The controller 53 controls the electromagnetic flow valves on the liquid inlet 42 and the liquid outlet 11 to be fully opened, and circulates the coolant into the battery pack body 1 at a high flow rate. The cooling method of the battery thermal management system is converted into active cooling of pouring immersion liquid cooling.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An immersion battery pack thermal management system, characterized in that: include: A battery pack case (1) has a accommodating chamber (10) with an opening at the top, the accommodating chamber (10) is filled with a cooling medium, and a liquid outlet (11) is provided on a bottom side wall of the battery pack case (1); A plurality of single cells (2) are arranged in a containing chamber (10) and immersed in a cooling medium; A phase-change working medium (3) is arranged in the accommodating chamber (10) and surrounds the outer side of the single battery (2); A cooling box (4) is fixedly arranged at the top opening of the battery pack box (1); the bottom surface of the cooling box (4) has a communication port (41) connected to the accommodating chamber (10); a liquid inlet (42) is provided on the cooling box (4); and electromagnetic flow valves are provided on the liquid inlet (42) and the liquid outlet (11); The control system (5) comprises a first temperature sensor (51), a second temperature sensor (52) and a controller (53); the first temperature sensor (51) is arranged inside a battery pack box (1) and is used to detect the temperature of a single battery (2); the second temperature sensor (52) is used to detect the temperature of a coolant in the battery pack box (1); the first temperature sensor (51), the second temperature sensor (52) and the electromagnetic flow valve are electrically connected to the controller (53) respectively.

2. The submerged battery pack thermal management system according to claim 1, characterized in that: A first partition (6) and a second partition (7) are fixedly arranged in the upper and lower parts of the accommodating chamber (10), and the first partition (6) divides the accommodating chamber (10) from top to bottom into a first chamber (101), a second chamber (102) and a third chamber (103); The cooling box (4) is fixedly arranged in the first chamber (101), the communication port (41) is in communication with the first chamber (101), and the liquid outlet (11) is in communication with the third chamber (103); A plurality of sleeves (8) are vertically fixedly arranged between the first partition (6) and the second partition (7), and two ends of the sleeves (8) extend out of the outside of the first partition (6) and the second partition (7) respectively; The single cell (2) is vertically fixedly arranged in the sleeve (8), and a flow channel (81) is arranged between the single cell (2) and the sleeve (8), the flow channel (81) connects the first chamber (101) and the third chamber (103), and the phase change working medium (3) is arranged in the second chamber (102).

3. The submerged battery pack thermal management system according to claim 2, characterized in that: The phase change working medium (3) comprises solid granular phase change material (31) filled in the second chamber (102).

4. The submerged battery pack thermal management system according to claim 3, characterized in that: The phase change working medium (3) further comprises a coating layer (32), the coating layer (32) being filled with the phase change material (31), a plurality of first liquid permeable holes (82) being provided on the outer wall of the sleeve (8), and the second chamber (102) and the flow channel (81) being connected via the first liquid permeable holes (82).

5. The submerged battery pack thermal management system according to claim 4, characterized in that: The second partition plate (7) is provided with a plurality of second liquid-permeable holes (71), and the second chamber (102) and the third chamber (103) are connected via the second liquid-permeable holes (71).

6. The submerged battery pack thermal management system according to any one of claims 3 to 5, characterized in that: A plurality of single cells (2) are arranged vertically to form a plurality of battery packs (20); a cooling box (4) is fixedly arranged in a first chamber (101) where the upper end of each battery pack (20) is located; a plurality of communication ports (41) are arranged on the bottom surface of the cooling box (4); and the plurality of communication ports (41) correspond one by one to the plurality of single cells (2) in the battery pack (20) in a vertical manner.

7. The submerged battery pack thermal management system according to claim 6, characterized in that: The connecting port (41) is a circular hole structure, a guide plate (43) of a circular structure is coaxially arranged inside the connecting port (41), an annular flow channel (44) is provided between the guide plate (43) and the connecting port (41), a connecting rod (45) is fixedly provided on the top surface of the guide plate (43) and the top surface of the inner cavity of the cooling box (4), and the annular flow channel (44) corresponds to the position of the flow channel (81).

8. The submerged battery pack thermal management system according to claim 7, characterized in that: The bottom surface of the cooling box (4) contacts the top surface of the first partition (6).

9. The submerged battery pack thermal management system according to claim 7, characterized in that: A gap is provided between the bottom surface of the cooling box body (4) and the top surface of the first partition plate (6), and the first partition plate (6) is provided with a plurality of third liquid permeable holes (61) which are connected to the second chamber (102).

10. A method for thermal management of an immersed battery pack, which utilizes the thermal management system of an immersed battery pack according to any one of claims 2 to 9, characterized in that: The steps include: S1. When the first temperature sensor measures that the temperature of the single cell is lower than 40°C, the electromagnetic flow valves on the liquid inlet and the liquid outlet are in a closed state, and the static coolant in the sleeve and the phase-changing working fluid outside the sleeve cooperate to achieve heat dissipation of the single cell; S2. When the first temperature sensor measures that the temperature of the single cell is higher than 40°C, and the second temperature sensor measures that the temperature of the coolant is lower than 35°C, the controller controls the electromagnetic flow valves on the liquid inlet and the liquid outlet to open slightly, and circulates the coolant into the battery pack at a low flow rate. The coolant flows through the surface of the single cell to take away the heat, and the phase change working fluid absorbs the heat in the coolant, assisting the thermal management system to achieve active and passive synchronous heat dissipation; S3. When the second temperature sensor measures that the coolant temperature is higher than 35°C, the phase change material is basically completely melted. The controller controls the electromagnetic flow valves on the liquid inlet and outlet to be fully opened, and circulates the coolant into the battery pack body at a high flow rate. The cooling method of the battery thermal management system is converted to active cooling of pouring immersion liquid cooling.

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