An immersion liquid-cooled lithium battery pack

Abstract

The utility model discloses a kind of immersion liquid-cooled lithium battery PACK packs in the field of lithium battery PACK, including the cabinet that is filled with cooling liquid inside, at least two groups of fixed battery cell module soaked in cooling liquid are equipped in cabinet, battery cell module is composed of at least two simultaneously electrically conductive connection battery cell monomer, the same battery cell module is equipped with the coil fixing piece of interval fixed battery cell monomer;Refrigeration coil is further equipped in cabinet and soaked in cooling liquid, and the refrigeration coil is used for one-way delivery refrigerant, refrigeration coil is repeatedly bent and surrounds above each battery cell monomer, and cabinet side surface is equipped with air conditioning liquid pipe connection mouth connected with the input end of refrigeration coil and air conditioning gas pipe connection mouth connected with the output end of refrigeration coil. By soaking battery cell monomer in cooling liquid, the area of contact between the two is increased, and the heat of battery cell monomer is absorbed by heat exchange, refrigeration coil is also added in cooling liquid, the heat emitted by battery cell monomer can be quickly taken away, and the situation of thermal runaway is inhibited.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery pack technology, specifically to an immersion liquid-cooled lithium battery pack. Background Technology

[0002] With the rapid development of new energy technologies, energy storage cabinets, as the core equipment of large-scale energy storage systems, play a crucial role in grid peak shaving, renewable energy consumption, and backup power. Lithium-ion battery packs, as the core energy storage unit of energy storage cabinets, combine multiple lithium-ion battery cells in series and parallel, and integrate management systems, protection circuits, and other components to achieve efficient storage and release of electrical energy. Their performance directly affects the safety, stability, and service life of the energy storage cabinet.

[0003] During the operation of a lithium battery pack, the charging and discharging of the cells will generate a lot of heat. If the heat cannot be dissipated in a timely and effective manner, the cell temperature will rise, causing problems such as battery capacity decay and shortened cycle life, and may even lead to safety accidents such as thermal runaway.

[0004] Currently, there are two main cooling methods commonly used in immersion liquid-cooled lithium battery packs: one is immersion liquid cooling technology, which exchanges heat directly with the cell surface through coolant circulation. However, due to limitations in fluid dynamics, the coolant is prone to temperature stratification and flow dead zones within the pack, resulting in significant temperature differences between cells. The other improved approach involves adding localized air conditioning evaporators within the battery pack. While this can improve localized cooling intensity, it is difficult to achieve uniform temperature control across all cells due to the fixed position of the evaporator and the attenuation of heat transfer. Neither of these solutions can achieve uniform heat dissipation from the cells, leading to significant temperature differences between cells within the lithium battery pack, which fails to meet the increasing demands for battery safety and reliability in energy storage systems. Utility Model Content

[0005] In order to overcome the shortcomings of existing technical solutions, this utility model provides an immersion liquid-cooled lithium battery pack, which can effectively solve the technical problems of slow heat dissipation and uneven heat dissipation inside the current lithium battery pack.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] An immersion liquid-cooled lithium battery PACK includes a chassis filled with coolant. The chassis contains at least two sets of cell modules fixed in the coolant. Each cell module consists of at least two simultaneously conductive cell units. The same cell module contains coil fixing components that fix the cell units at intervals.

[0008] The chassis is also equipped with a refrigeration coil immersed in coolant, which is used to unidirectionally transport refrigerant. The refrigeration coil is repeatedly bent and wrapped around each battery cell. The side of the chassis is provided with an air conditioning liquid pipe connection port connected to the input end of the refrigeration coil and an air conditioning gas pipe connection port connected to the output end of the refrigeration coil.

[0009] Furthermore, the top of the chassis has an opening, and a sealed cover is fitted at the opening. A sealing ring is also provided at the connection between the cover and the chassis for sealing.

[0010] Furthermore, the side of the chassis is provided with an oil inlet and an oil outlet that communicate with the interior, with the oil inlet located above the oil outlet.

[0011] Furthermore, the side of the chassis is also provided with a sampling line adapter terminal that connects to the inside of the chassis.

[0012] Furthermore, the same cell module also includes at least two PCBs electrically connected to individual cells, and the PCBs are fixed to the top of the corresponding coil fixing component. A first conductive connecting piece is connected between adjacent PCBs in the same cell module, and a second conductive connecting piece is provided between adjacent cell modules to connect two adjacent PCBs. The side of the chassis is provided with a positive terminal and a negative terminal connected to one of the PCBs in different cell modules.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This invention increases the contact area between the battery cells and the battery cells by completely immersing the individual cells in the coolant. It also rapidly absorbs the heat from the battery cells through heat exchange. In addition, a cooling coil surrounding all the battery cells is added to the coolant to quickly remove the heat emitted by the battery cells, ensuring that all battery cells are in a uniform temperature state and preventing thermal runaway of the battery cells. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0016] Figure 2 This is a schematic diagram of the first internal structure of the chassis according to an embodiment of the present utility model;

[0017] Figure 3 This is a schematic diagram of the second internal structure of the chassis in an embodiment of this utility model;

[0018] Figure 4 This is a schematic diagram of the refrigeration coil structure according to an embodiment of the present utility model;

[0019] Figure 5This is a schematic diagram of the battery cell module structure according to an embodiment of the present invention;

[0020] Figure 6 This is a schematic diagram showing the connection between the refrigeration coil and the outdoor unit of the air conditioner in an embodiment of this utility model;

[0021] Numbering on the map:

[0022] 1-Chassis, 101-Air conditioning liquid pipe connection port, 102-Air conditioning gas pipe connection port, 103-Cover plate, 104-Oil inlet, 105-Oil outlet, 106-Sampling line adapter terminal, 107-Positive terminal, 108-Negative terminal;

[0023] 2-Battery cell module, 201-Battery cell, 202-Coil fixing component, 203-PCB board, 204-First connecting piece, 205-Second connecting piece, 206-Fixing part;

[0024] 3-Refrigeration coil;

[0025] 4-Sealing ring;

[0026] 5-Air conditioner outdoor unit, 501-Pipe, 502-Refrigerant output end, 503-Refrigerant return end. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] like Figure 1-6 As shown, this utility model provides an immersion liquid-cooled lithium battery pack, mainly used for battery power supply. After optimization, the internal structure of the lithium battery pack improves the problems of slow heat dissipation and temperature difference between battery cells in traditional lithium battery packs.

[0029] The lithium battery pack's specific structure mainly includes a chassis 1, battery cell modules 2, and a cooling coil 3. The chassis 1 is a sealed structure with an IP68 rating and is filled with coolant for cooling the internal battery cell modules 2. There are two battery cell modules 2, both completely immersed in the coolant. During power supply, the battery cell modules 2 generate heat, which is absorbed by the coolant, causing its temperature to rise. The cooling coil 3, connected to the outdoor unit 5 of an air conditioner, supplies refrigerant to the interior. As the refrigerant flows through the coil, it comes into contact with the heated coolant, absorbing heat and thus cooling the coolant to maintain the temperature of the immersed battery cell modules 2.

[0030] The chassis 1 has a hollow structure and is filled with coolant. On one side of chassis 1, there is an oil inlet 104 and an oil outlet 105, both of which are open to the interior. Users can inject coolant into chassis 1 through the oil inlet 104 and drain coolant through the oil outlet 105. Therefore, in terms of location, the oil inlet 104 is located at the top of chassis 1, while the oil outlet 105 is located at the bottom. In addition, the oil inlet 104 can also be used for internal pressure relief and regulation. A sampling line adapter terminal 106 is also provided on the side of chassis 1, connecting to the interior. Users can use this sampling line adapter terminal 106 to measure and monitor the voltage and current inside the lithium battery pack to ensure safe battery operation and performance maintenance.

[0031] Additionally, the top of the chassis 1 has an opening, and a sealed cover 103 is fitted at the opening. When assembly is required inside the lithium battery pack, the user can open the cover 103 to assemble the internal cell modules 2. Furthermore, after prolonged use, the user can also open the cover 103 to clean and maintain the interior of the chassis 1 and replace the coolant. To enhance the seal between the cover 103 and the chassis 1, a reinforced sealing ring 4 is added at the connection point. This sealing ring 4 can be a silicone ring or other soft rubber ring.

[0032] The chassis 1 contains two sets of battery cell modules 2, each immersed in coolant and powered by a single cell. Each battery cell module 2 consists of 26 simultaneously conductive battery cells 201, which provide power during use. The battery cells 201 within the same battery cell module 2 are arranged in a 13x2 matrix structure. A coil fixing component 202 is also provided to secure the 26 battery cells 201. The 26 battery cells 201 are evenly spaced and fixed to the bottom of the chassis 1.

[0033] To ensure that the individual battery cells 201 within each battery cell module 2 can be powered simultaneously, each battery cell module 2 includes two PCB boards 203 connected to the individual battery cells 201. The two PCB boards are longitudinally parallel and fixed to the top of the corresponding coil fixing component 202. Each PCB board 203 can be electrically connected to the 13 individual battery cells 201 arranged in the same column via nickel-plated soldering. Simultaneously, a first connecting piece 204 is provided between the two PCB boards 203 within the same battery cell module 2, connected at their ends, while a second connecting piece 205 is provided between the two adjacent PCB boards 203. A positive terminal 107 and a negative terminal 108 connected to the internal battery cell modules 2 are also provided on the side of the chassis 1. In the two battery cell modules 2, the front ends of the PCB boards 203 not connected to the second connecting piece 205 are respectively connected to the positive terminal 107 and the negative terminal 108. The internal power of the lithium battery pack can be obtained by connecting the positive terminal 107 and the negative terminal 108.

[0034] Inside the housing 1, there is also a refrigerant coil 3, which, like the battery module 2, is immersed in coolant. The refrigerant coil 3 is mainly used to absorb heat from the coolant. Meanwhile, on the outside of the housing 1, there are air conditioning liquid pipe connection ports 101 and air conditioning gas pipe connection ports 102, which connect to both ends of the refrigerant coil 3. The air conditioning liquid pipe connection ports 101 and 102 are used to connect to the outdoor unit 5 of the air conditioner and to unidirectionally supply refrigerant into the refrigerant coil 3. During connection, the air conditioning liquid pipe connection port 101 serves as the input end of the refrigerant coil 3, while the air conditioning gas pipe connection port 102 serves as the output end of the refrigerant coil 3. Specifically, when connected to the outdoor unit 5, the air conditioning liquid pipe connection port 101 is connected to the refrigerant output end 502 of the outdoor unit 5 via a pipe 501, while the air conditioning gas pipe connection port 102 is connected to the refrigerant return end 503 of the outdoor unit 5 via a pipe 501. At this time, the refrigerant is compressed by the compressor of the outdoor unit 5 and then transported in a high-temperature, high-pressure liquid form through the air conditioner liquid pipe connection port 101 to the interior of the cooling coil 3. Inside the cooling coil 3, the refrigerant absorbs heat from the coolant and gradually vaporizes. Finally, it flows back to the outdoor unit 5 through the air conditioner gas pipe connection port 102 for recompression and cooling, forming a cycle. This process ensures the unidirectional flow of the refrigerant and effective cooling.

[0035] The cooling coil 3, immersed in the coolant, needs to absorb heat from the coolant while also promoting uniform temperature distribution around each battery cell 201. Therefore, it requires extending the time the cooling coil 3 remains in the coolant and structurally bending repeatedly around each battery cell 201. To achieve this, the cooling coil 3 adopts a U-shaped structure after a central bend, with both extended ends bending synchronously and repeatedly in the same direction, resulting in repeated S-shaped bends. This bending not only extends the refrigerant's residence time in the coolant but also rapidly absorbs the rising heat released from around each battery cell 201, accelerating the cooling rate. Additionally, multiple fixing parts 206 for securing the cooling coil 3 are provided at the top of the coil fixing component 202.

[0036] When the lithium battery pack is in use, heat is generated during the power supply process of the cell module 2. This heat is absorbed by the coolant, causing the temperature of the coolant inside the housing 1 to rise. The cooling coil 3 is connected to the outdoor unit 5 of the air conditioner. The refrigerant output terminal 502 of the outdoor unit 5 supplies refrigerant to the cooling coil 3 through the air conditioner liquid pipe connection port 101. After absorbing the heat from the coolant, the refrigerant gradually vaporizes and absorbs a large amount of heat from the coolant, thus lowering the temperature of the coolant. This, in turn, lowers the temperature of each cell 201. The vaporized refrigerant then flows back to the refrigerant return terminal 503 of the outdoor unit 5 through the air conditioner gas pipe connection port 102 for further compression and cooling.

[0037] Compared with traditional technologies, this technical solution increases the contact area between the coolant and the battery cell 201 by completely immersing the battery cell 201 in the coolant. It also rapidly absorbs the heat of the battery cell 201 through heat exchange. At the same time, a cooling coil 3 is added around all the battery cells 201 in the coolant, which can quickly remove the heat dissipated by the battery cell 201, so that all the battery cells 201 are in a uniform temperature state and the occurrence of thermal runaway of the battery cell 201 is suppressed.

[0038] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An immersion liquid-cooled lithium battery pack, comprising a chassis internally filled with coolant, characterized in that: The chassis contains at least two sets of battery cell modules that are fixed in coolant. Each battery cell module consists of at least two battery cells that are simultaneously electrically connected. The same battery cell module contains coil fixing components that fix the battery cells at intervals. The chassis is also equipped with a refrigeration coil immersed in coolant, which is used to unidirectionally transport refrigerant. The refrigeration coil is repeatedly bent and wrapped around each battery cell. The side of the chassis is provided with an air conditioning liquid pipe connection port connected to the input end of the refrigeration coil and an air conditioning gas pipe connection port connected to the output end of the refrigeration coil.

2. The immersion liquid-cooled lithium battery pack according to claim 1, characterized in that: The top of the chassis has an opening, and a sealed cover is fitted at the opening. A sealing ring is also provided at the connection between the cover and the chassis for sealing.

3. The immersion liquid-cooled lithium battery pack according to claim 1, characterized in that: The side of the chassis is provided with an oil inlet and an oil outlet that communicate with the interior, with the oil inlet located above the oil outlet.

4. A submersible liquid-cooled lithium battery pack according to any one of claims 1-3, characterized in that: The side of the chassis is also equipped with a sampling line adapter terminal that connects to the inside of the chassis.

5. A submersible liquid-cooled lithium battery pack according to any one of claims 1-3, characterized in that: The same cell module also includes at least two PCBs electrically connected to the individual cells, and the PCBs are fixed to the top of the corresponding coil fixing component. A first conductive connecting piece is connected between adjacent PCBs in the same cell module, and a second conductive connecting piece is provided between adjacent cell modules to connect two adjacent PCBs. The side of the chassis is provided with a positive terminal and a negative terminal connected to one of the PCBs in different cell modules.

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