Liquid-cooled energy storage battery pack and cooling control method thereof

Abstract

The application discloses a liquid-cooled energy storage battery pack and a cooling control method thereof, and relates to the technical field of energy storage equipment. The technical scheme is as follows: a battery pack box body comprises a containing chamber with an open top, the bottom of the battery pack box body is provided with a variable cross-section flow channel in a first direction, the cross-sectional area of the variable cross-section flow channel decreases from the beginning to the end in the first direction, and the top is provided with a slit; a liquid inlet is communicated with the variable cross-section flow channel; a liquid outlet is arranged on one side of the battery pack box body close to the bottom and is communicated with the containing chamber; a hollow vertical plate is vertically fixed to the bottom of the box body, and the containing chamber is divided into a battery cell mounting area; a battery cell module is mounted in the battery cell mounting area; a plurality of groups of spray holes are arranged on the side wall of the hollow vertical plate at different heights, and the hole diameters of the spray holes at different heights increase from bottom to top.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage devices, more particularly, it relates to a liquid-cooled energy storage battery pack and a cooling control method thereof. BACKGROUND

[0002] The energy storage battery is one of the core components of the electrochemical energy storage system, and its performance directly affects the working condition of the energy storage system. During the operation of the energy storage battery, a large amount of heat is generated due to the intense chemical reaction inside the battery, which causes the temperature of the battery to rise. The temperature of the energy storage battery directly affects the safety, charging and discharging capacity and efficiency, cycle life and other performances of the battery. In addition, the single cell of the energy storage battery usually needs to be assembled into a cell module to meet the use requirements, so the uniformity of the temperature of the cell module is also an important guarantee for the normal performance of the battery. If the cooling system of the battery cannot effectively dissipate the heat in time and uniformly, the temperature distribution of the modules will be inconsistent, which will exacerbate the inconsistency of the internal resistance and capacity of the battery, and have a negative impact on the service life, and even cause safety hazards.

[0003] At present, the mainstream battery cooling methods on the market are mainly air-cooled cooling and immersion liquid-cooled cooling. The battery structure of the immersion liquid-cooled cooling mainly includes a box body, the inside of the box body is a conventional box space, the cell module is installed in the box body, and the liquid inlet and the liquid outlet are arranged on the front panel of the box body and are in direct communication with the inside of the box body. The cooling liquid is injected into the box body through the liquid inlet, fills all the remaining space between the cell module and the inner wall of the box body, and forms and maintains a set liquid level in the box body. The cooling liquid at the liquid level directly contacts the surface of the cell for heat exchange, absorbs the heat generated by the cell, and after heat exchange, the cooling liquid with increased temperature is collected at the bottom of the box body under the action of gravity and finally flows out from the liquid outlet at the bottom.

[0004] In the above-mentioned method, a large amount of cooling liquid is needed to fill the remaining space between the cell module and the inner wall of the box body, and the amount of cooling liquid is large. At the same time, the liquid inlet and the liquid outlet are connected to the front panel of the box body. Since the front and back of the box body usually have a long distance, there are some areas with slow flow speed when the cooling liquid flows to the back of the box body. The heat of the cell module in this area is difficult to be taken away, resulting in poor uniformity of the temperature of the cell module in the box body.

[0005] Therefore, a new scheme is needed to solve this problem. SUMMARY

[0006] Therefore, the purpose of the present application is to provide an immersion energy storage device, which realizes uniform spraying of the cooling liquid to the surface of the cell module by arranging the variable cross-section flow channel and the hollow vertical plate with increasing aperture from bottom to top.

[0007] To achieve the above object, the technical scheme adopted by the present application is as follows: a liquid-cooled energy storage battery pack comprises:

[0008] a battery pack box body including a top-open accommodating chamber, a bottom of the battery pack box body being provided with a variable cross-section flow channel in a first direction, the first direction being a flow direction of the cooling liquid, a cross-sectional area of the variable cross-section flow channel decreasing from a first end to a second end in the first direction, and a top of the variable cross-section flow channel being provided with a slit, a length of the slit being consistent with a length of the variable cross-section flow channel;

[0009] a liquid inlet communicating with the variable cross-section flow channel at the first end in the first direction;

[0010] a liquid outlet provided on a side of the battery pack box body close to the bottom and located at the first end in the first direction and communicating with the accommodating chamber;

[0011] a hollow vertical plate vertically fixed to the bottom of the box body, the accommodating chamber being divided into a cell mounting area by the hollow vertical plate, an interior of the hollow vertical plate communicating with the variable cross-section flow channel through the slit;

[0012] a cell module mounted in the cell mounting area;

[0013] wherein a plurality of groups of spray holes are provided on a side wall of the hollow vertical plate at different heights, and the spray holes at different heights have diameters increasing from bottom to top to balance fluid resistance and gravity of the cooling liquid flowing from bottom to top and to realize uniform spraying of the cooling liquid to a surface of the cell module.

[0014] Preferably, a lower end of the hollow vertical plate is provided with a connecting port communicating with the interior of the hollow vertical plate, and the connecting port is adapted to the slit.

[0015] Preferably, a plurality of the hollow vertical plates are provided at intervals in a second direction, each of the hollow vertical plates being provided with the variable cross-section flow channel and the slit, the second direction being perpendicular to the first direction, and the plurality of the hollow vertical plates divide the accommodating chamber into a plurality of the cell mounting areas, and the cell module is mounted in each of the cell mounting areas.

[0016] Preferably, the hollow vertical plates located on both sides of the accommodating chamber are provided with the spray holes only on a side facing the cell module, and the plurality of the hollow vertical plates located in a middle part of the accommodating chamber are provided with the spray holes on both sides.

[0017] Preferably, a flow-through hole is provided on a side close to the bottom of the battery pack box body between the plurality of the hollow vertical plates located in the middle part of the accommodating chamber, and the flow-through hole is used to communicate adjacent cell mounting areas so that the cooling liquid after heat exchange flows to the liquid outlet and out of the battery pack box body.

[0018] Preferably, the flow-through hole is arranged at one end of the hollow vertical plate close to the liquid outlet.

[0019] Preferably, a first flow electromagnetic valve for controlling the input amount of cooling liquid is arranged on the liquid inlet, and a second flow electromagnetic valve for controlling the output amount of cooling liquid is arranged on the liquid outlet.

[0020] Preferably, a cover plate is further included, which is connected and fixed to the battery pack box body by bolts.

[0021] A heat exchange control method of a liquid-cooled energy storage battery pack, which utilizes the liquid-cooled energy storage battery pack, includes a full immersion heat exchange control method and a spraying heat exchange control method.

[0022] The full immersion heat exchange control method includes the following steps:

[0023] Step 1: increase the first flow electromagnetic valve to a first specified opening degree, and decrease the second flow electromagnetic valve to a second specified opening degree, wherein the first specified opening degree is greater than the second specified opening degree.

[0024] Step 2: after the cooling liquid flows through the liquid inlet, the variable cross-section flow channel, the hollow vertical plate, the spraying hole and the liquid outlet in sequence, the liquid level in the accommodation chamber can rise to cover the top of the battery cell module, realizing the immersion heat exchange of the battery cell module.

[0025] The spraying heat exchange control method includes the following steps:

[0026] S1, decrease the first flow electromagnetic valve to a third specified opening degree, and increase the second flow electromagnetic valve to a fourth specified opening degree, wherein the third specified opening degree is less than the fourth specified opening degree.

[0027] S2, after the cooling liquid flows through the liquid inlet, the variable cross-section flow channel, the hollow vertical plate, the spraying hole and the liquid outlet in sequence, the liquid level height in the accommodation chamber tends to be zero, and in this process, the cooling liquid is sprayed to the surface of the battery cell module in the form of a liquid film.

[0028] Compared with the prior art, the advantages of the liquid-cooled energy storage battery pack and its heat exchange control method disclosed in this invention are as follows: By setting a variable cross-section flow channel, when the coolant flows from the first end to the end in the first direction, although part of the flow will be diverted into the hollow vertical plate through the slit in the initial stage, the cross-sectional area of ​​the variable cross-section flow channel decreases synchronously from the first end to the end in the first direction. According to the principle of fluid continuity, the coolant in the variable cross-section flow channel can maintain the same flow rate as in the initial stage when it continues to flow. This method effectively compensates for the decrease in flow rate caused by flow diversion, so that when the coolant passes through the slit, the same and sufficient flow rate can be maintained at any position in the length direction of the slit. This avoids the problem of the coolant flow rate at the rear of the box being too slow or even forming a dead zone in the traditional method. Furthermore, by setting multiple sets of spray holes at different heights on the side wall of the hollow vertical plate, the aperture of the spray holes at different heights increases from bottom to top, which balances the fluid resistance and gravity encountered by the coolant when it flows from bottom to top, and achieves uniform spraying of coolant to the surface of the cell module. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a liquid-cooled energy storage battery pack according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the battery pack housing according to an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of the hollow vertical plate according to an embodiment of this application;

[0033] Figure 4 This is a side view of the battery pack housing according to an embodiment of this application;

[0034] Figure 5 for Figure 4 Sectional view at point AA;

[0035] Figure 6 This is a top view of the battery pack housing according to an embodiment of this application;

[0036] Figure 7 for Figure 6 Sectional view at point BB;

[0037] Figure 8 for Figure 7 Enlarged view of section C in the image;

[0038] Figure 9 This is a schematic diagram of the flow hole structure in an embodiment of this application.

[0039] The numbers or letters in the attached diagram represent the names of the corresponding components:

[0040] 1. Battery pack housing; 2. Liquid inlet; 3. Liquid outlet; 4. Cell module; 5. Cover plate; 6. Hollow vertical plate; 61. Spray hole; 7. Variable cross-section flow channel; 8. Slit; 12. Flow hole. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described through specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] Please see Figures 1 to 8 This application provides a liquid-cooled energy storage battery pack, including a battery pack housing 1, a liquid inlet 2, a liquid outlet 3, a hollow vertical plate 6, and battery cell modules 4. It also includes a cover plate 5, which is connected and fixed to the battery pack housing 1 by bolts.

[0043] The battery pack housing 1 includes a top-opening accommodating chamber. A variable cross-section flow channel 7 is provided at the bottom of the battery pack housing 1 along a first direction. The cross-sectional area of ​​the variable cross-section flow channel 7 decreases from its beginning to its end along the first direction. A slit 8 is provided at the top of the variable cross-section flow channel 7, and the length of the slit 8 is the same as the length of the variable cross-section flow channel 7. The first direction is... Figure 2 The X direction shown is the flow direction of the coolant, i.e., the front-to-back direction. The Y direction is defined as the second direction, i.e., the left-to-right direction, and the Z direction is the up-to-down direction, i.e., the height direction. The X, Y, and Z directions are perpendicular to each other. The inlet 2 includes variable cross-section flow channels 7 that are connected to the first end located in the first direction. The outlet 3 is located on the side of the battery pack housing 1 near the bottom, at the first end in the first direction, and is connected to the receiving chamber.

[0044] The hollow vertical plate 6 is vertically fixed to the bottom of the battery pack box body 1, divides the accommodation chamber to form a battery cell mounting area, the inside of the hollow vertical plate 6 is communicated with the variable cross-section flow channel 7 through the slit 8, specifically, the lower end of the hollow vertical plate 6 is provided with a connecting port communicated with the inside of the hollow vertical plate 6, the connecting port is adapted to the slit 8, the peripheral side of the connecting port can be welded with the bottom of the battery pack box body 1 located on the peripheral side of the slit 8, to realize the fixed connection of the hollow vertical plate 6 and the bottom of the battery pack box body 1, and maintain the sealing of the connection. The hollow vertical plate 6 is made of a metal material with high heat conduction capacity. A plurality of groups of spray holes 61 are arranged on the side wall of the hollow vertical plate 6 at different heights, the fluid pressure is the highest at the bottom of the hollow vertical plate 6 and relatively small at the top, by setting the hole diameters of the spray holes 61 at different heights to increase from bottom to top, the flow regulation effect caused by the change of the hole diameters is utilized, the natural decreasing trend of the flow caused by the decreasing pressure from bottom to top and the resistance loss and gravity resistance is offset, so that the flow of the cooling liquid sprayed by the spray holes 61 at different heights tends to be consistent.

[0045] In the above manner, by arranging the variable cross-section flow channel 7, when the cooling liquid flows from the first direction from the head end to the tail end, although part of the flow is shunted into the hollow vertical plate 6 through the slit 8 in the initial stage, since the cross-sectional area of the variable cross-section flow channel 7 decreases synchronously from the head end to the tail end in the first direction, according to the principle of fluid continuity, the flow rate of the cooling liquid in the variable cross-section flow channel 7 can be maintained the same as that in the initial stage when the cooling liquid continues to flow, this manner effectively compensates for the flow rate drop caused by the flow shunting, so that the cooling liquid can maintain the same and sufficient flow rate at any position in the length direction of the slit 8 when passing through the slit 8, avoiding the problem that the flow rate of the cooling liquid is too slow or even forms a dead zone at the rear of the box body in the traditional manner. By arranging a plurality of groups of spray holes 61 on the side wall of the hollow vertical plate 6 at different heights, the hole diameters of the spray holes 61 at different heights increase from bottom to top, so that the fluid resistance and gravity received by the cooling liquid when flowing from bottom to top are balanced, and uniform spraying of the cooling liquid to the surface of the battery cell module 4 is realized. The hollow vertical plate 6 is made of a metal material with high heat conduction capacity, so that the cooling liquid reaches temperature balance between different regions, and the uniformity of the battery cell module 4 is improved.

[0046] A plurality of hollow vertical plates 6 are arranged at intervals along the second direction, each of the hollow vertical plates 6 is correspondingly provided with a variable cross-section flow channel 7 and a slit 8, the second direction is perpendicular to the first direction, the plurality of hollow vertical plates 6 divide the accommodation chamber to form a plurality of battery cell mounting areas, each of the battery cell mounting areas is provided with a battery cell module 4. The hollow vertical plates 6 located on both sides of the accommodation chamber are provided with spray holes 61 only on the side facing the battery cell module 4, and the hollow vertical plates 6 located in the middle of the accommodation chamber are provided with spray holes 61 on both sides. In this manner, by arranging a plurality of hollow vertical plates 6 for partitioning, the cooling can be performed in different areas, and the remaining space volume of the battery pack box body 1 is reduced to a certain extent, which is beneficial to saving the amount of cooling liquid.

[0047] Please refer to Figure 9 The plurality of hollow vertical plates 6 located in the middle of the accommodation chamber are provided with flow-through holes 12 on one side close to the bottom of the battery pack box 1. The flow-through holes 12 are used to communicate adjacent cell mounting areas, so that the cooled cooling liquid falls to the bottom of the battery pack box 1 under the action of gravity, and flows through the flow-through holes 12 to the liquid outlet 3 and flows out of the battery pack box 1. Further, the flow-through holes 12 are arranged at one end of the hollow vertical plate 6 close to the liquid outlet 3. The cooling liquid falling to the bottom of the battery pack box 1 directly flows through the flow-through hole 12 closest to the liquid outlet 3 in the second direction, realizing the shortest and most direct waste heat cooling liquid discharge path, reducing the overall pressure drop of the system and the power consumption of the pump circulation.

[0048] The liquid inlet 2 is provided with a first flow electromagnetic valve (not shown) for controlling the input amount of cooling liquid, and the liquid outlet 3 is provided with a second flow electromagnetic valve (not shown) for controlling the output amount of cooling liquid. The first flow electromagnetic valve, the second flow electromagnetic valve and the temperature sensor are respectively electrically connected with the PLC controller. The first flow electromagnetic valve can be connected with a conveying pump for conveying cooling liquid, and the second flow electromagnetic valve can be connected with a suction pump for extracting waste heat cooling liquid. By arranging the first flow electromagnetic valve and the second flow electromagnetic valve, the input and output amounts of cooling liquid can be accurately adjusted in real time.

[0049] The application also discloses a heat exchange control method of a liquid-cooled energy storage battery pack, which utilizes the liquid-cooled energy storage battery pack. The control method includes a full immersion heat exchange control method and a spraying heat exchange control method.

[0050] The full immersion heat exchange control method includes the following steps:

[0051] Step 1, increase the first flow electromagnetic valve to a first specified opening degree, and reduce the second flow electromagnetic valve to a second specified opening degree, wherein the first specified opening degree is greater than the second specified opening degree.

[0052] Step 2, the cooling liquid flows through the liquid inlet 2, the variable cross-section flow channel 7, the hollow vertical plate 6, the spraying hole 61 and the liquid outlet 3 in sequence, and the liquid level in the accommodation chamber can rise to cover the top of the cell module 4, realizing the immersion heat exchange of the cell module 4. This method is suitable for working conditions with high heat dissipation demand.

[0053] The spraying heat exchange control method includes the following steps:

[0054] S1, reduce the first flow electromagnetic valve to a third specified opening degree, and increase the second flow electromagnetic valve to a fourth specified opening degree, wherein the third specified opening degree is less than the fourth specified opening degree.

[0055] S2, the liquid level in the accommodating chamber approaches zero after the cooling liquid flows through the liquid inlet 2, the variable cross-section flow channel 7, the hollow vertical plate 6, the spray hole 61 and the liquid outlet 3 in sequence, and in this process, the cooling liquid is sprayed in the form of a spray to the surface of the battery module 4 to form a liquid film. This method is suitable for working conditions with small heat dissipation requirements, and can greatly save the amount of cooling liquid.

[0056] It should be noted that the specific values of the first specified opening degree, the second specified opening degree, the third specified opening degree and the fourth specified opening degree are reasonably set by the PLC controller in actual working conditions, and are not specifically limited.

[0057] The above description of disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A liquid-cooled energy storage battery pack, characterized in that, include: The battery pack housing includes a receiving chamber with a top opening. A variable cross-section flow channel is provided at the bottom of the battery pack housing along a first direction, where the first direction is the flow direction of the coolant. The cross-sectional area of ​​the variable cross-section flow channel decreases from the beginning to the end along the first direction. A slit is provided at the top of the variable cross-section flow channel, and the length of the slit is the same as the length of the variable cross-section flow channel. The liquid inlet is connected to the variable cross-section flow channel located at the head end in the first direction; The liquid outlet is located on the side of the battery pack housing near the bottom and at the first end in the first direction, and communicates with the receiving chamber. A hollow vertical plate is vertically fixed to the bottom of the housing, dividing the accommodating chamber to form a cell mounting area. The interior of the hollow vertical plate is connected to the variable cross-section flow channel through the slit. The battery cell module is installed in the battery cell mounting area; Multiple hollow vertical plates are spaced apart along the second direction. Each hollow vertical plate is provided with a variable cross-section flow channel and a slit. The second direction is perpendicular to the first direction. The multiple hollow vertical plates divide the accommodating chamber to form multiple cell mounting areas. Each cell mounting area is equipped with a cell module. The hollow vertical plate has multiple sets of spray holes at different heights on its sidewalls. The diameter of the spray holes at different heights increases from bottom to top to balance the fluid resistance and gravity encountered by the coolant when it flows from bottom to top, so as to achieve uniform spraying of coolant to the surface of the battery cell module.

2. The liquid-cooled energy storage battery pack according to claim 1, characterized in that: The lower end of the hollow vertical panel is provided with a connection port that communicates with the interior of the hollow vertical panel, and the connection port is adapted to the slit.

3. The liquid-cooled energy storage battery pack according to claim 1, characterized in that: The hollow upright plates located on both sides of the accommodating chamber have spray holes only on the side facing the battery cell module, while the multiple hollow upright plates located in the middle of the accommodating chamber have spray holes on both sides.

4. The liquid-cooled energy storage battery pack according to claim 3, characterized in that: A flow hole is provided on one side of the multiple hollow vertical plates located in the middle of the accommodating chamber, near the bottom of the battery pack housing. The flow hole is used to connect the adjacent cell mounting area, so that the coolant after heat exchange flows to the outlet and flows out of the battery pack housing.

5. The liquid-cooled energy storage battery pack according to claim 4, characterized in that: The flow hole is located at one end of the hollow vertical plate near the liquid outlet.

6. The liquid-cooled energy storage battery pack according to claim 1, characterized in that: The inlet is equipped with a first flow solenoid valve for controlling the amount of coolant input, and the outlet is equipped with a second flow solenoid valve for controlling the amount of coolant output.

7. The liquid-cooled energy storage battery pack according to claim 1, characterized in that: It also includes a cover plate, which is fixed to the battery pack housing by bolts.

8. A heat exchange control method for a liquid-cooled energy storage battery pack, which utilizes the liquid-cooled energy storage battery pack as described in claim 6, characterized in that: This includes fully submerged heat exchange control methods and spray heat exchange control methods; The fully submersible heat exchange control method includes the following steps: Step 1: Increase the opening of the first flow solenoid valve to a first specified degree, and decrease the opening of the second flow solenoid valve to a second specified degree, wherein the first specified degree is greater than the second specified degree; Step 2: After the coolant flows through the inlet, the variable cross-section flow channel, the hollow vertical plate, the spray hole and the outlet in sequence, the liquid level in the accommodating chamber can rise to cover the top of the battery cell module, realizing the immersion heat exchange of the battery cell module; The spray-type heat exchange control method includes the following steps: S1. Reduce the first flow solenoid valve to a third specified opening degree, and increase the second flow solenoid valve to a fourth specified opening degree, wherein the third specified opening degree is less than the fourth specified opening degree; S2. After the coolant flows through the inlet, the variable cross-section flow channel, the hollow vertical plate, the spray hole and the outlet in sequence, the liquid level in the accommodating cavity approaches zero. During this process, the coolant is sprayed onto the surface of the cell module to form a liquid film.

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