Liquid cooling energy storage battery pack and cooling control method thereof

Abstract

The invention discloses a liquid-cooled energy storage battery pack and a cooling control method thereof, and relates to the technical field of energy storage equipment, and the key points of the technical scheme are that the liquid-cooled energy storage battery pack comprises a battery pack box body which comprises a containing cavity with a top opening, and the bottom of the battery pack box body is provided with a variable cross-section flow channel along a first direction; the cross section area of the variable-section runner is gradually reduced from the head end to the tail end in the first direction, and a slit is formed in the top of the variable-section runner; the liquid inlet is communicated with the variable cross-section runner; the liquid outlet is formed in one side, close to the bottom, of the battery pack box body and is communicated with the accommodating chamber; the hollow vertical plate is vertically fixed at the bottom of the box body and divides the accommodating chamber into battery cell mounting areas; the battery cell module is mounted in the battery cell mounting area; a plurality of groups of spraying holes are formed in the side wall of the hollow vertical plate along different heights, and the hole diameters of the spraying holes at different heights are gradually increased from bottom to top. By arranging the variable cross-section flow channels and the hollow vertical plates with gradually increased apertures from bottom to top, uniform spraying of the cooling liquid to the surface of the battery cell module is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage equipment, and more particularly, to a liquid-cooled energy storage battery pack and a cooling control method thereof. Background Art

[0002] Energy storage batteries are one of the core components of electrochemical energy storage systems, and their performance is directly related to the operating conditions of the energy storage system. During operation, energy storage batteries provide electrical energy through violent chemical reactions. During the charging and discharging process, a large amount of heat is generated, causing the battery temperature to rise. The temperature of the energy storage battery will directly affect the battery's safety, charge and discharge capacity and efficiency, cycle life and other performance. In addition, the single cells of energy storage batteries usually need to be composed of cell modules to meet usage requirements. Therefore, the temperature consistency of the cell modules is also an important guarantee for the normal performance of the battery. If the battery cooling system cannot effectively dissipate heat in a timely and uniform manner, it will cause inconsistent temperature distribution between modules. This will aggravate the internal resistance and capacity inconsistency of the battery, have a negative impact on the service life, and in serious cases, there will be safety hazards.

[0003] Currently, the mainstream battery cooling methods on the market are mostly air cooling and immersion liquid cooling. Among them, the battery structure of immersion liquid cooling mainly includes a box body. The interior of the box body is a conventional box space. The battery cell module is installed in the box body. A liquid inlet and a liquid outlet directly connected to the interior of the box body are set on the front panel of the box body. The coolant is injected into the box body through the liquid inlet, filling all the remaining space between the battery cell module and the inner wall of the box body, and forming and maintaining a set liquid level in the box body. The coolant at this liquid level is in direct contact with the surface of the battery cell for heat exchange, absorbing the heat generated by the battery cell. After the heat exchange is completed, the coolant with increased temperature gathers to 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 method, a large amount of coolant is needed to fill the remaining space between the battery cell module and the inner wall of the box, and the amount of coolant used is large; at the same time, the liquid inlet and outlet are connected to the front panel of the box. Since the front and back of the box are usually a long distance apart, there will be some areas with slower flow speed when the coolant flows to the rear. The heat of the battery cell module in this area is difficult to be taken away, resulting in poor temperature uniformity of the battery cell module in the box.

[0005] Therefore, a new solution needs to be proposed to solve this problem. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide an immersion energy storage device, which realizes uniform spraying of coolant to the surface of the battery cell module by setting a variable cross-section flow channel and a hollow vertical plate with increasing aperture from bottom to top.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a liquid-cooled energy storage battery pack, comprising:

[0008] A battery pack case includes a accommodating chamber with an open top, a variable-section flow channel provided at the bottom of the battery pack case along a first direction, the first direction being the direction of flow of the coolant, the cross-sectional area of ​​the variable-section flow channel decreasing from a beginning to a end along the first direction, and a slit provided at the top of the variable-section flow channel, the length of the slit being consistent with the length of the variable-section flow channel;

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

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

[0011] A hollow vertical plate is vertically fixed to the bottom of the box body, dividing the accommodating chamber to form a battery cell installation area, and the interior of the hollow vertical plate is connected to the variable-section flow channel through the slit;

[0012] A battery cell module is installed in the battery cell installation area;

[0013] Among them, multiple groups of spray holes are arranged at different heights along the side walls of the hollow vertical plate, and the apertures of the spray holes at different heights increase from bottom to top to balance the fluid resistance and gravity encountered by the coolant when flowing from bottom to top, thereby achieving uniform spraying of the coolant to the surface of the battery cell module.

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

[0015] Preferably, a plurality of the hollow vertical panels are arranged at intervals along the second direction, each of the hollow vertical panels is correspondingly provided with the variable-section flow channel and the slit, the second direction is perpendicular to the first direction, and the plurality of the hollow vertical panels separate the accommodating chamber to form a plurality of the battery cell installation areas, and the battery cell module is installed in each of the battery cell installation areas.

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

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

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

[0019] Preferably, the liquid inlet is provided with a first flow solenoid valve for controlling the input amount of the coolant, and the liquid outlet is provided with a second flow solenoid valve for controlling the output amount of the coolant.

[0020] Preferably, it also includes a cover plate, which is connected and fixed to the battery pack box by bolts.

[0021] A heat exchange control method for a liquid-cooled energy storage battery pack, which utilizes the liquid-cooled energy storage battery pack, including a full immersion heat exchange control method and a spray heat exchange control method;

[0022] The fully immersed heat exchange control method comprises the following steps:

[0023] Step 1: increasing the first flow solenoid valve to a first specified opening, and decreasing the second flow solenoid valve to a second specified opening, wherein the first specified opening is greater than the second specified opening;

[0024] Step 2: After the coolant flows through the liquid inlet, the variable-section flow channel, the hollow vertical plate, the spray hole, and the liquid outlet in sequence, the liquid level in the accommodating chamber can rise to cover the top of the battery module, thereby realizing immersion heat exchange of the battery module;

[0025] The spray heat exchange control method comprises the following steps:

[0026] S1. Reduce the first flow solenoid valve to a third specified opening, and increase the second flow solenoid valve to a fourth specified opening, where the third specified opening is smaller than the fourth specified opening;

[0027] S2. After the coolant flows through the liquid inlet, the variable-section flow channel, the hollow vertical plate, the spray hole and the liquid outlet in sequence, the liquid level height in the accommodating chamber approaches zero. During this process, the coolant is sprayed onto the surface of the battery cell module in a spraying manner to form 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 the present invention are: by setting a variable-section flow channel, when the coolant flows from the head end to the end in the first direction, although part of the flow will be diverted through the slit into the hollow vertical plate in the initial stage, since the cross-sectional area of ​​the variable-section flow channel decreases synchronously from the head end to the end in the first direction, according to the principle of fluid continuity, the coolant in the variable-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 flow rate drop 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, avoiding the problem of slow coolant flow rate or even dead zone at the rear of the box in the traditional method, and by setting multiple groups of spray holes at different heights on the side wall of the hollow vertical plate, the apertures of the spray holes at different heights increase from bottom to top, so as to balance the fluid resistance and gravity encountered by the coolant when flowing from bottom to top, and achieve uniform spraying of the coolant to the surface of the battery cell module. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

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

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

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

[0033] Figure 4 A side view of a battery pack case according to an embodiment of the present application;

[0034] Figure 5 for Figure 4 Cross-sectional view at AA in the middle;

[0035] Figure 6 A top view of a battery pack case according to an embodiment of the present application;

[0036] Figure 7 for Figure 6 Cross-sectional view at the middle BB;

[0037] Figure 8 for Figure 7 Enlarged view of part C in FIG;

[0038] Figure 9 Schematic diagram of the structure of the flow hole in an embodiment of the present application.

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

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

[0041] The technical solutions of the present invention will be clearly and completely described below through specific implementation methods. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0042] See Figures 1 to 8 The embodiment of the present application provides a liquid-cooled energy storage battery pack, comprising a battery pack case 1, a liquid inlet 2, a liquid outlet 3, a hollow vertical plate 6, and a battery cell module 4. It also includes a cover plate 5, which is fixed to the battery pack case 1 by bolts.

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

[0044] The hollow vertical plate 6 is fixed vertically to the bottom of the battery pack case 1, dividing the accommodating chamber to form a cell installation area. The interior of the hollow vertical plate 6 is connected to the variable-section flow channel 7 through a slit 8. Specifically, the lower end of the hollow vertical plate 6 is provided with a connection port that communicates with the interior of the hollow vertical plate 6. The connection port is adapted to the slit 8. The peripheral side of the connection port can be welded to the bottom of the battery pack case 1 located on the side of the slit 8, achieving a fixed connection between the hollow vertical plate 6 and the bottom of the battery pack case 1 and maintaining a tight connection. The hollow vertical plate 6 is made of a metal material with high thermal conductivity. A plurality of groups of spray holes 61 are provided at different heights along the upper edge of the side wall of the hollow vertical plate 6. The fluid pressure at the bottom of the hollow vertical plate 6 is the highest, and the fluid pressure at the top is relatively small. By setting the apertures of the spray holes 61 at different heights to increase from bottom to top, the flow regulating effect generated by the aperture change is utilized to offset the natural decreasing trend of the flow caused by the pressure decreasing from bottom to top and the resistance loss and the counteraction of gravity, so that the flow rate of the coolant sprayed from the spray holes 61 at different heights tends to be consistent.

[0045] In the above-described method, by providing a variable cross-section flow channel 7, when the coolant flows from the beginning to the end in the first direction, although part of the flow will be diverted through the slit 8 into the hollow vertical plate 6 in the initial stage, because the cross-sectional area of ​​the variable cross-section flow channel 7 decreases synchronously from the beginning to the end in the first direction, according to the principle of fluid continuity, the coolant in the variable cross-section flow channel 7 can maintain the same flow rate as in the initial stage when it continues to flow. This method effectively compensates for the flow rate drop caused by the flow diversion, so that when the coolant passes through the slit 8, the same and sufficient flow rate can be maintained at any position along the length of the slit 8, avoiding the problem of the coolant flow rate being too slow or even forming a dead zone at the rear of the box in the traditional method. By providing multiple groups of spray holes 61 at different heights along the side wall of the hollow vertical plate 6, the apertures of the spray holes 61 at different heights increase from bottom to top, so as to balance the fluid resistance and gravity encountered by the coolant when flowing from bottom to top, and achieve uniform spraying of the coolant to the surface of the battery cell module 4. The hollow vertical plate 6 is made of a metal material with high thermal conductivity, so that the coolant can achieve temperature balance between different areas, thereby improving the temperature uniformity of the battery module 4.

[0046] Multiple hollow vertical panels 6 are arranged at intervals along the second direction, each of which is provided with a variable-section flow channel 7 and a slit 8. The second direction is perpendicular to the first direction, and the multiple hollow vertical panels 6 divide the accommodating chamber into multiple battery cell installation areas, each of which is equipped with a battery cell module 4. The hollow vertical panels 6 located on both sides of the accommodating chamber are provided with spray holes 61 only on the side facing the battery cell module 4. The multiple hollow vertical panels 6 located in the middle of the accommodating chamber are provided with spray holes 61 on both sides. In this method, by providing multiple hollow vertical panels 6 to create partitions, cooling can be performed in different areas, and the remaining space volume of the battery pack case 1 is reduced to a certain extent, which helps save the amount of coolant used.

[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. After the coolant flows through the liquid inlet 2, the variable-section flow channel 7, the hollow vertical plate 6, the spray hole 61 and the liquid outlet 3 in sequence, the liquid level in the accommodating chamber approaches zero. During this process, the coolant is sprayed onto the surface of the battery cell module 4 in a spraying manner to form a liquid film. This method is suitable for working conditions with low heat dissipation requirements and can greatly save the amount of coolant used.

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

[0057] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to 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: A battery pack case includes a accommodating chamber with an open top, a variable-section flow channel provided at the bottom of the battery pack case along a first direction, the first direction being the direction of flow of the coolant, the cross-sectional area of ​​the variable-section flow channel decreasing from a beginning to a end along the first direction, and a slit provided at the top of the variable-section flow channel, the length of the slit being consistent with the length of the variable-section flow channel; a liquid inlet, communicating with the variable-cross-section flow channel located at the head end in the first direction; a liquid outlet, provided on one side of the battery pack body close to the bottom, located at the head end in the first direction, and communicated with the accommodating chamber; A hollow vertical plate is vertically fixed to the bottom of the box body, dividing the accommodating chamber to form a battery cell installation area, and the interior of the hollow vertical plate is connected to the variable-section flow channel through the slit; A battery cell module is installed in the battery cell installation area; A plurality of hollow vertical panels are arranged at intervals along the second direction, each of the hollow vertical panels is correspondingly provided with the variable-section flow channel and the slit, the second direction is perpendicular to the first direction, and the plurality of hollow vertical panels divide the accommodating chamber into a plurality of battery cell installation areas, each of the battery cell installation areas is installed with the battery cell module; Among them, multiple groups of spray holes are arranged at different heights along the side walls of the hollow vertical plate, and the apertures of the spray holes at different heights increase from bottom to top to balance the fluid resistance and gravity encountered by the coolant when flowing from bottom to top, thereby achieving uniform spraying of the 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 plate is provided with a connection port communicating with the interior of the hollow vertical plate, 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 vertical plates located on both sides of the accommodating chamber are provided with the spray holes only on the side facing the battery core module, and the multiple hollow vertical plates located in the middle of the accommodating chamber are provided with the 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 between the multiple hollow vertical plates located in the middle of the accommodating chamber on one side close to the bottom of the battery pack body. The flow hole is used to connect adjacent battery cell installation areas so that the cooling liquid after heat exchange flows to the liquid outlet and flows out of the battery pack body.

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

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

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

8. A heat exchange control method for a liquid-cooled energy storage battery pack, utilizing the liquid-cooled energy storage battery pack according to claim 6, characterized in that: Including full immersion heat exchange control method and spray heat exchange control method; The fully immersed heat exchange control method comprises the following steps: Step 1: increasing the first flow solenoid valve to a first specified opening, and decreasing the second flow solenoid valve to a second specified opening, wherein the first specified opening is greater than the second specified opening; Step 2: After the coolant flows through the liquid inlet, the variable-section flow channel, the hollow vertical plate, the spray hole, and the liquid outlet in sequence, the liquid level in the accommodating chamber can rise to cover the top of the battery module, thereby realizing immersion heat exchange of the battery module; The spray heat exchange control method comprises the following steps: S1. Reduce the first flow solenoid valve to a third specified opening, and increase the second flow solenoid valve to a fourth specified opening, where the third specified opening is smaller than the fourth specified opening; S2. After the coolant flows through the liquid inlet, the variable-section flow channel, the hollow vertical plate, the spray hole and the liquid outlet in sequence, the liquid level height in the accommodating chamber approaches zero. During this process, the coolant is sprayed onto the surface of the battery cell module in a spraying manner to form a liquid film.

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