Immersed liquid cooling energy storage battery box

Abstract

The invention discloses an immersed liquid cooling energy storage battery box, and belongs to the technical field of outdoor integrated cabinets. The box body assembly comprises a box body and a cover plate covering the top of the box body, a baffle is arranged at the bottom of the box body, the baffle is arranged in a guide groove, a liquid inlet is formed in the bottom end of the end of the box body, and a liquid outlet is formed in the top end of the end of the box body; the battery assembly comprises a battery module which is arranged on the baffle and is composed of a plurality of battery cells, overflow runners are formed among the battery cells through isolation pads, and the guide grooves are communicated with the overflow runners; cooling liquid enters from the liquid inlet, is shunted to the overflow flow channel through the guide groove and flows between the bottom of the box body and the battery cell; the cooling liquid adopted by the invention is an insulating cooling liquid, the PACK adopts a totally-closed pressure-bearing design, the system pressure can meet 0.2 mPa, negative pressure vacuumizing liquid injection is performed, a reasonable flow channel is constructed, the cooling liquid heat dissipation capability is improved, the front and rear temperatures of the battery cell are basically consistent, and the temperature rise of the battery cell is reduced.

Description

Technical Field

[0001] The invention relates to an immersion type liquid-cooled energy storage battery box, belonging to the technical field of outdoor integrated cabinets. Background Art

[0002] As the economy continues to develop, urban electricity use continues to reach new peaks. However, electricity resources are becoming increasingly scarce. Improving the utilization rate of electricity resources is a way to solve the current dilemma. Energy storage technology has gradually developed as a new type of electricity. Energy storage technology can not only ensure the continuity and stability of new energy power supply and improve the quality of electricity, but also achieve energy time shifting by peak shaving and valley filling, thereby improving energy utilization.

[0003] As energy storage technology develops faster and faster, the energy density of electrochemical energy storage cells is getting higher and higher, which poses a severe challenge to the heat dissipation of the cells. At present, more than 70% of electrochemical energy storage on the market use liquid cooling plates to dissipate heat for the cells. This form mainly transfers heat through the bottom or side of the cell. The overall temperature rise of the cell is high, the temperature uniformity of the cell is not high, and it is not suitable for high-rate charging and discharging. In order to improve the heat dissipation capacity of the cell, the concept of a fully immersed liquid-cooled battery box is proposed. However, the currently designed and published immersed liquid-cooled battery boxes are mostly non-pressure-bearing structures. The heat is mainly dissipated by heat exchange between the immersed cooling medium and the external high specific heat heat dissipation medium. It is essentially indirect heat exchange, and the temperature consistency of the cell is poor. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a pressurized immersion liquid-cooled energy storage battery box to solve the problem of uneven high-rate heat dissipation temperature between battery cells and improve the heat dissipation efficiency of the battery cells; In order to achieve the above purpose / solve the above technical problems, the present invention is implemented by adopting the following technical solutions: An immersion liquid-cooled energy storage battery box, comprising: The box assembly comprises a box and a cover plate covering the top of the box, a spacer is provided at the bottom of the box, a guide groove is provided below the spacer, a liquid inlet is provided at the bottom end of the box end, and a liquid outlet is provided at the top end; A battery assembly, comprising a battery module composed of a plurality of battery cells arranged on a spacer, wherein an overflow channel is formed between the battery cells through the spacer, and the guide groove is connected to the overflow channel; When the coolant enters from the liquid inlet, it is diverted through the guide groove to the overflow channel and flows to the bottom of the box and between the battery cells.

[0005] Optionally, the guide groove gradually increases in width along the depth direction.

[0006] Optionally, the spacer is provided with a protrusion for constructing a guide flow channel.

[0007] Optionally, a CCS sampling harness for sampling is provided above the battery cell.

[0008] Optionally, the CCS sampling harness samples a flexible printed circuit board.

[0009] Optionally, pressure-bearing reinforcing ribs are provided between the battery modules.

[0010] Optionally, insulating material is filled between the battery module and the box.

[0011] Optionally, the liquid inlet and the liquid outlet are provided with two-way stop valves.

[0012] Optionally, a groove is processed on the flange surface of the box to install the sealing gasket, a circular groove is opened at the position of the middle reinforcing rib bolt to install the O-ring, and the corresponding cover plate is provided with reinforcing ribs. When the cover plate is assembled with the box body, it is positioned by the locating pins on the box body, and the reinforcing ribs on the cover plate are pressed against the middle area of ​​the sealing gasket.

[0013] Optionally, the cover plate has a pressure bearing capacity of at least 0.2 mPa.

[0014] Optionally, the entire PACK is subjected to a negative pressure of 0.1 mPa.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The coolant used in the present invention is an insulating coolant, which adopts a fully enclosed pressure-bearing design to truly realize direct heat exchange and construct a reasonable flow channel to solve the problems of insufficient heat dissipation capacity of the liquid cold plate for high-rate charging and discharging of the battery cells and poor temperature uniformity of the battery cells. The coolant is confined to a specific area, reducing the use of coolant and reducing the overall cost of the immersion battery box. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a layout diagram of the submerged liquid-cooled battery box of the present invention; Figure 2 This is a structural diagram of the front wall of the immersed liquid-cooled battery box of the present invention; Figure 3 This is a cooling liquid flow diagram of the liquid inlet of the immersion liquid-cooled battery box in the present invention; Figure 4 It is a flow diagram of the cooling liquid inside the battery cell of the immersion liquid-cooled battery box of the present invention; Figure 5 This is a simulation effect diagram of the box body and cover plate of the present invention; Figure 6 It is the UFD curve diagram of the spacer of the present invention; Figure 7-Figure 8 This is a simulation effect diagram of negative pressure of the box and cover plate of the present invention; Figure 9-11 This is a simulation effect diagram of the box structure strength of the present invention; Figure 12-Figure 15 This is a simulation effect diagram of the structure optimization of the present invention; In the figure: 1, box assembly, 1-1, box, 1-2, box cover, 1-3, spacer, 1-4, liquid inlet, 1-5, liquid outlet, 1-6, protrusion, 1-7, guide groove, 1-8, overflow channel; 2. Battery assembly, 2-1. Battery module, 2-2. CCS sampling harness, 2-3. Baffle. DETAILED DESCRIPTION

[0017] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0020] like Figure 1-Figure 4As shown, an immersion liquid-cooled energy storage battery box of the present invention includes a box assembly 1 and a battery assembly 2, the box assembly includes a box 1-1, a spacer 1-3 and a cover plate 1-2 covering the top of the box 1-1, the front wall of the box 1-1 is provided with two liquid inlets 1-4, one liquid outlet 1-5, four collection harness plugs and positive and negative electrode bases, wherein the bottom end of the front wall is provided with a liquid inlet 1-4, and the top end is provided with a liquid outlet 1-5. The purpose of such design is that the coolant gradually fills the bottom of the battery cell in the overflow channel 1-8, and then flows along the battery cell flow channel to the upper surface of the battery cell and accumulates on the upper surface of the battery cell, and flows out from the liquid outlet 1-5 to take away the heat.

[0021] A spacer 1-3 is provided at the bottom of the box body 1-1, and a guide groove 1-7 is provided below the spacer 1-3; The battery assembly 2 includes a battery module 2-1 composed of multiple battery cells arranged on a spacer 1-3, an overflow channel 1-8 is formed between the battery cells through the spacer 1-3, and the guide groove 1-7 is connected to the overflow channel 1-8; the battery module 2-1 is respectively installed in two spaces of the box body 1-1, when the coolant enters the box body 1-1 through the liquid inlet 1-4, the coolant is diverted to the tail of the battery along the guide groove 1-7, during the flow process, the coolant overflows through both sides of the guide groove 1-7 into the bottom of the battery module, and then flows along the overflow channel 1-8 between the battery cells to the top of the battery module 2-1, and finally flows out of the box body through the liquid outlet 1-5.

[0022] In order to facilitate the disassembly and maintenance of a single battery box, two-way stop valves are installed at the liquid inlet 1-4 and the liquid outlet 1-5 respectively.

[0023] In the specific implementation process of this embodiment, the liquid inlet and the liquid outlet are threaded with G3 / 8, the two-way stop valve is installed at the liquid inlet 1-4 and the liquid outlet 1-5, and then the pagoda head water nozzle is installed on the two-way stop valve, and the water pipe is connected to the pagoda head. When the battery box needs to be maintained and repaired, the water pipe can be directly unplugged, and the two-way stop valve can be opened to recover the coolant. If only the water pipe is replaced, the coolant will not flow out of the box when the water pipe is unplugged.

[0024] In the specific implementation of this embodiment, in order to ensure that the coolant flows along the set flow channel, a reinforcing rib is provided inside the box 1-1 connected to the liquid inlet, a guide groove 1-7 is smoothly processed on the reinforcing rib, overflow ports are opened on both sides of the guide groove 1-7, the overflow flow channel 1-8 is consistent with the vertical direction of the battery cell flow, and the baffle 2-3 is bonded on the guide groove 1-7. After the coolant enters the box 1-1, it is restricted by the baffle 2-3 and can only flow in the guide groove 1-7.

[0025] When the coolant runs in the guide groove 1-7, it is affected by the flow resistance, and the flow rate of the coolant becomes slower and slower along the depth direction of the box body. Therefore, the width of the guide groove 1-7 gradually increases along the depth direction, thereby ensuring that the flow rate of each overflow port is basically consistent. The coolant flows to both sides through the overflow channel. The two sides of the bottom of the battery module are fixed to the box body by sealing strips. The coolant can only flow in the closed area after entering the bottom of the battery module 2-1. When the coolant fills the bottom area of ​​the battery module 2-1, it flows toward the upper part of the battery cell along the flow channel set by the baffle 2-3, thereby achieving heat dissipation on the six sides of the battery cell and improving the heat dissipation efficiency of the coolant.

[0026] The interior of the battery module 2-1 is an effective coolant area, and the remaining areas are ineffective heat dissipation areas, so insulating materials are used to fill them to reduce the use of coolant.

[0027] In the specific implementation of this embodiment, the spacer 1-3 is provided with a protrusion 1-6 for placing the battery cell. The purpose of this design is that the battery cell is placed on the protrusion 1-6, and the coolant can enter the bottom of the battery cell along the overflow channel to cool the bottom of the battery cell.

[0028] To ensure the sealing requirements of the box assembly 1, a groove is opened on the flange surface of the box 1-1 to install the sealing strip, and a reinforcing rib is added to the cover 1-2 accordingly. In addition, two positioning pin holes are opened on the box 1-1. The positioning pins are fixed during assembly to ensure that the reinforcing rib on the cover 1-2 can be effectively pressed on the sealing strip.

[0029] In the specific implementation process of this embodiment, there is a reinforcing rib in the middle of the box body 1-1, and bolts are installed on the upper part. Therefore, the middle reinforcing rib of the box body 1-1 and the corresponding reinforcing ribs of the cover plate are finely processed. At the same time, a groove is opened at the position where the bolts are installed on the middle reinforcing rib of the box body 1-1 to place an O-ring to ensure the sealing requirements of the box body.

[0030] During the specific implementation of this embodiment, the aluminum scar on the top of the battery module 2-1 and the CCS sampling harness 2-2 use PET packaging film to replace the traditional PC blister shell structure to eliminate the deposition of coolant caused by the reinforcement ribs of the PC blister shell, and the ineffective area between the CCS sampling harness 2-2 and the cover plate 1-2 can be filled with insulating material.

[0031] In order to meet the transportation vibration standards required by the new national standard GB / T 36276-2023, the box assembly 1 is made of a low-pressure casting process as a whole. After heat treatment, the yield strength of the box reaches 260MPa.

[0032] like Figure 7-11Simulation effect: During the specific implementation of this embodiment, the cover plate has a bearing pressure of at least 0.2 MPa. Through simulation analysis, the static load stresses of the box 1-1 and the cover plate 1-2 are 0.45 MPa and 147 MPa respectively, the cover plate displacement is 1 mm, and the three-way transport vibration of the box is 32 MPa, 47 MPa, and 1.86 MPa respectively, all meeting the requirements.

[0033] Because the liquid outlet is not at the top, considering the requirements of immersion liquid replenishment, the entire PACK needs to be vacuumed for liquid replenishment, so the PACK needs to withstand a negative pressure of 0.1Mpa.

[0034] When making immersion cabinets and container products, there will be clusters of 5 or 8 PACKs, and the water cooling system will dissipate heat for multiple PACKs. The viscosity of the insulating cooling medium used in immersion increases as the temperature decreases. Considering the application of immersion energy storage products under low temperature conditions, the system pressure of each PACK is relatively high under low temperature startup conditions. Taking the low temperature of -30℃ as the minimum startup condition, the pressure that the PACK cover 1-2 needs to withstand is about 2bar, so a simulation check is carried out. For details, see Figure 5 , Figure 6 .

[0035] In this embodiment, the system group design needs to apply a certain preload force to the battery cell. The preload force range of the fresh battery cell is 500~3000N. The battery cell will generate expansion force during use. Under the test condition that the initial large surface clamp force of the 15mm aluminum plate is 3000±200N, the expansion force of the battery cell attenuated to 70% is about 35000N. Therefore, when designing the flow channel, the spacers 1-3 are reversely calculated according to the above requirements, and the UF-470 foam spacer is selected. The specific UFD curve is as follows Figure 7 As shown; According to the thermal simulation results, the overall heat dissipation efficiency is optimal when the cell gap is 2mm. The size of the spacer 1-3 is 200X20X2.7mm. The specific pressure requirements are shown in the table below. Considering the flow channel size, the width of the spacer 1-3 is reduced from 20mm to 15mm, and the thickness is increased from 2.7mm to 3.3mm. Please refer to the table below for specific calculations:

[0036] like Figure 12-Figure 15The simulation results show that the coolant used in the present invention is an insulating coolant, which adopts a fully enclosed pressure-bearing design to truly realize direct heat exchange and construct a reasonable flow channel to solve the problem of insufficient heat dissipation capacity of the liquid cold plate for high-rate charge and discharge of the battery cell and poor temperature uniformity of the battery cell. The coolant is limited to a specific area, reducing the use of coolant and the overall cost of the immersion battery box. Through simulation calculation, it is shown that at a rate of 0.5C, the temperature of the entire battery module is within 30°C, the temperature difference of the battery cell is within 2°C, and the amount of coolant used is reduced to 0.288L / KWh.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An immersion liquid-cooled energy storage battery box, characterized in that: include: A box assembly (1) comprises a box (1-1) and a cover plate (1-2) covering the top of the box (1-1); a spacer (1-3) is provided at the bottom of the box (1-1); a guide groove (1-7) is provided below the spacer (1-3); a liquid inlet (1-4) is provided at the bottom end of the box (1-1) and a liquid outlet (1-5) is provided at the top end; A battery assembly (2) comprises a battery module (2-1) composed of a plurality of battery cells arranged on a spacer (1-3), an overflow channel (1-8) being formed between the battery cells through the spacer (1-3), and the guide groove (1-7) being in communication with the overflow channel (1-8); When the coolant enters from the liquid inlet (1-4), it is diverted through the guide groove (1-7) to the overflow channel (1-8) and flows to the bottom of the box body (1-1) and between the battery cells.

2. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: The guide groove (1-7) gradually increases in width along the depth direction.

3. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: The spacer (1-3) is provided with a protrusion (1-6) for constructing a guide flow channel.

4. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: A CCS sampling harness (2-2) for sampling is provided above the battery cell.

5. The submerged liquid-cooled energy storage battery box according to claim 4, characterized in that: The CCS sampling harness (2-2) samples the flexible circuit board.

6. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: Pressure-bearing reinforcing ribs are provided between the battery modules (2-1).

7. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: Insulating material is filled between the battery module (2-1) and the box body (1-1).

8. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: The liquid inlet (1-4) and the liquid outlet (1-5) are provided with two-way stop valves.

9. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: The flange surface of the housing (1-1) is machined with a groove for installing a sealing gasket, a circular groove is opened at the position of the middle reinforcing rib bolt to install an O-ring, and a corresponding cover plate (1-2) is provided with reinforcing ribs. When the cover plate (1-2) and the housing (1-1) are assembled, they are positioned by means of positioning pins on the housing, and the reinforcing ribs on the cover plate (1-2) are pressed against the middle area of ​​the sealing gasket.

10. The submerged liquid-cooled energy storage battery box according to claim 1, characterized in that: The cover plate (1-2) withstands a pressure of at least 0.2 mPa, and the entire battery PACK withstands a negative pressure of 0.1 mPa.

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