Liquid-cooled battery pack based on lithium-sodium battery cell

Abstract

The invention discloses a liquid-cooled battery pack based on a lithium-sodium battery cell, and relates to the technical field of batteries. According to the scheme, the liquid-cooled battery pack comprises a battery assembly formed by alternately arranging a plurality of lithium cells and a plurality of sodium cells, the sodium cells and the lithium cells are combined, the battery assembly integrating the advantages of the sodium cells and the lithium cells is obtained, the overall comprehensive performance of the liquid-cooled battery pack is improved, meanwhile, liquid cooling plates are arranged on the bottom face and the top face of a box body respectively, and therefore the liquid cooling effect is improved. The condition of uneven contact cooling of a single surface of the battery cell is avoided, meanwhile, the contact area with the battery assembly is increased, and the heat dissipation effect is improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a liquid-cooled battery pack based on lithium-sodium battery cells. Background Art

[0002] Energy shortage and environmental pollution have made new energy technologies with energy conservation and environmental protection advantages increasingly concerned globally. Electrochemical energy storage technology realizes the storage and release of electrical energy through rechargeable batteries, providing important support for new energy power generation. Electrochemical energy storage technology can be divided into lead-acid batteries, lithium-ion batteries, flow batteries, sodium-sulfur batteries, etc. according to different materials, and there are great differences in performance characteristics and cost-effectiveness among various energy storage technologies.

[0003] Currently, the rechargeable batteries commonly used in the new energy field have the problems of single advantages and poor comprehensive performance. At the same time, due to the single-sided contact between the heat dissipation system and the battery cells in the battery pack, the cooling is uneven and the heat dissipation effect is poor. Summary of the Invention

[0004] The embodiments of the present specification provide a liquid-cooled battery pack based on lithium-sodium battery cells to solve the problems of single advantages, poor comprehensive performance, and poor heat dissipation effect existing in the rechargeable batteries in the prior art.

[0005] To solve the above technical problems, the embodiments of the present specification are implemented as follows: A liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiments of the present specification includes: A box body; A battery assembly located inside the box body, including a plurality of lithium battery cells and a plurality of sodium battery cells, and the lithium battery cells and the sodium battery cells are arranged alternately; A liquid-cooling assembly including a first liquid-cooling plate and a second liquid-cooling plate. The first liquid-cooling plate is located at the bottom surface of the box body, and the second liquid-cooling plate is located at the top surface of the box body. Both the first liquid-cooling plate and the second liquid-cooling plate are used for heat exchange with the battery assembly.

[0006] An embodiment of the present specification can achieve the following beneficial effects: The liquid-cooled battery pack includes a battery assembly in which a plurality of lithium battery cells and a plurality of sodium battery cells are arranged alternately. By combining sodium battery cells and lithium battery cells, a battery assembly that integrates the advantages of sodium battery cells and lithium battery cells is obtained, improving the overall comprehensive performance of the liquid-cooled battery pack. At the same time, liquid-cooling plates are respectively arranged on the bottom surface and the top surface of the box body, avoiding the uneven cooling caused by single-sided contact of the battery cells, and at the same time increasing the contact area with the battery assembly, improving the heat dissipation effect. Description of the Drawings

[0007] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in this application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0008] Figure 1 Schematic structural diagram of the battery assembly provided by the embodiment of this specification; Figure 2 Overall structural diagram of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiment of this specification; Figure 3 Exploded view of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiment of this specification; Figure 4 Schematic electrical system diagram of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiment of this specification; Figure 5 Schematic electrical communication diagram of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiment of this specification.

[0009] Description of the drawings: 1 - Sodium battery cell; 2 - Lithium battery cell; 3 - Steel strip; 4 - Battery pack; 41 - First liquid cooling plate; 42 - Battery assembly; 43 - Second liquid cooling plate; 44 - External wiring port; 45 - Control module; 46 - Handle; 411 - Liquid outlet; 412 - Liquid inlet. Detailed implementation manners

[0010] To make the objectives, technical solutions, and advantages of one or more embodiments of this specification clearer, the following will clearly and completely describe the technical solutions of one or more embodiments of this specification in conjunction with the specific embodiments and the corresponding accompanying drawings of this specification. Obviously, the described embodiments are only some of the embodiments of this specification, rather than all of them. Based on the embodiments in this specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by one or more embodiments of this specification.

[0011] Energy shortages and environmental pollution have made new energy technologies with energy conservation and environmental protection advantages increasingly attracting global attention. Replacing fossil fuels such as oil with electric energy generated from new energy is a development trend that meets the requirements of green energy. In the early stage, green power generation forms such as photovoltaic power generation and wind power generation are often restricted by various factors such as geographical location, environment, intermittency, and cost. Electrochemical energy storage has emerged under this background. Currently, the mainstream electrochemical energy storage technologies include advanced lead-acid batteries (lead-carbon batteries), lithium-ion batteries (lithium iron phosphate, ternary lithium, etc.), flow batteries, and sodium-sulfur (sodium-ion) batteries, etc. There are significant differences in performance characteristics and cost-effectiveness among various energy storage technologies. So far, no single technology can meet the requirements of the five core energy storage performance indicators of cycle life, large-scale production, safety, cost-effectiveness, and energy efficiency at the same time.

[0012] In related technologies, lithium-ion batteries have a relatively high energy density and can store a large amount of energy with a relatively small volume and weight, making them suitable for applications such as portable electronic devices. However, the manufacturing cost of lithium-ion batteries is relatively high, and they are safe under normal use conditions, but may have safety problems such as overheating, combustion, or explosion in extreme cases. At the same time, lithium-ion batteries have poor low-temperature performance. In cold regions in the north and other extreme conditions, the capacity of lithium-ion battery packs will be significantly reduced during operation, or even shut down.

[0013] At present, the research, development, and production of sodium-ion cathode and anode materials have not yet formed large-scale industrialization compared with lithium-ion, resulting in difficult control of material costs. Compared with the theoretical cost, the cost reduction is not as expected. Compared with lithium-ion batteries, sodium-ion batteries are more stable in high-temperature environments, and in low-temperature environments, sodium-ion battery cells have better low-temperature resistance, reaching -40°C.

[0014] However, compared with lithium-ion batteries, sodium-ion batteries have a lower energy density, and a larger volume and weight are required to store the same amount of energy.

[0015] In order to solve the defects in the existing technology, the following embodiments are given in this solution: A liquid-cooled battery pack based on lithium-sodium battery cells provided in the embodiments of the specification is specifically described with reference to the accompanying drawings.

[0016] The liquid-cooled battery pack based on lithium-sodium battery cells in the embodiments of this specification may include: A box body; A battery assembly 42, located inside the box body, including a plurality of lithium battery cells 2 and a plurality of sodium battery cells 1, and the lithium battery cells 2 and the sodium battery cells 1 are arranged alternately; The liquid cooling assembly includes a first liquid cooling plate 41 and a second liquid cooling plate 43. The first liquid cooling plate 41 is located at the bottom surface of the box body, and the second liquid cooling plate 43 is located at the top surface of the box body. Both the first liquid cooling plate 41 and the second liquid cooling plate 43 are used for heat exchange with the battery assembly 42.

[0017] The liquid-cooled battery pack based on lithium-sodium battery cells may include a box body, a battery assembly 42, and a liquid cooling assembly.

[0018] In the embodiments of this specification, the box body provides structural support and protection for the battery assembly 42.

[0019] Figure 1 It is a schematic structural diagram of the battery assembly 42 provided by the embodiments of this specification.

[0020] The lithium battery cells 2 and the sodium battery cells 1 can be alternately arranged in a fixed ratio, such as Figure 1 As shown, the lithium battery cells 2 and the sodium battery cells 1 are cuboids. The lithium battery cells 2 and the sodium battery cells 1 are alternately arranged in a ratio of 1:1. The alternate arrangement can reduce the overall heat generation of the battery pack. At the same time, in a low-temperature environment, it can indirectly increase the ambient temperature around the battery cells, making it easier for the low-temperature-intolerant battery cells to reach the normal self-start temperature and improving the safety of the battery pack. The lithium battery cells 2 and the sodium battery cells 1 are arranged alternately and are isolated from each other in the system. Compared with the battery pack with only lithium battery cells 2 or sodium battery cells 1 discharging collectively, the heat generation is lower. When one type of battery cells discharges, the other spaced battery cells do not discharge, and the non-discharging battery cells can indirectly absorb the heat generated by the discharging battery cells. If in a low-temperature environment, it can indirectly increase the ambient temperature around the spaced battery cells to facilitate reaching the normal operating self-start temperature requirement and reduce the probability of thermal runaway of the battery cells. In order to integrate all the battery cells into a whole, a steel strip 3 can be used to bind the lithium battery cells 2 and the sodium battery cells 1 of the battery assembly 42. In practical applications, the battery pack 4 may include multiple groups of battery assemblies 42, and the battery assemblies 42 are arranged in the box body in a stacked form of up, down, left, and right.

[0021] Both the first liquid cooling plate 41 and the second liquid cooling plate 43 perform heat exchange with the battery assembly 42, and the heat generated by the battery assembly 42 is taken away by the circulating coolant, so as to keep the operating temperature of the battery pack 4 within the normal range. This liquid cooling plate structure configured up and down can form a stable temperature control cycle for the entire battery pack 4, effectively avoiding the occurrence of thermal runaway in a high-temperature environment.

[0022] In the embodiments of this specification, the liquid-cooled battery pack includes a battery assembly in which a number of lithium battery cells and a number of sodium battery cells are alternately arranged. By combining sodium battery cells with lithium battery cells, a battery assembly that integrates the advantages of sodium battery cells and lithium battery cells is obtained, improving the overall comprehensive performance of the liquid-cooled battery pack. At the same time, liquid-cooled plates are respectively arranged on the bottom surface and the top surface of the box body, avoiding the situation of uneven cooling due to single-sided contact of the battery cells, and at the same time increasing the contact area with the battery assembly, improving the heat dissipation effect.

[0023] To further improve the safety of the battery pack 4, further, in the embodiments of this specification, the liquid-cooled battery pack based on lithium-sodium battery cells may further include: The positive electrode direction of the lithium battery cell 2 is set opposite to the positive electrode direction of the sodium battery cell 1.

[0024] In the embodiments of this specification, the electrode directions of the lithium-sodium battery cells 1 are opposite. Even if lithium undergoes thermal runaway and the puncture valve is damaged for a period of time, it will not affect the vulnerable part of the sodium ion battery cell electrode.

[0025] Further, in the embodiments of this specification, the liquid-cooled battery pack based on lithium-sodium battery cells may further include: A battery management system, including an acquisition module for acquiring the battery information of the lithium battery cell 2 and the sodium battery cell 1, and the acquisition module includes a voltage collector and a temperature collector; Based on the voltage data acquired by the voltage collector and the temperature data acquired by the temperature collector, control the charging and discharging of the lithium battery cell 2 and the charging and discharging of the sodium battery cell 1 based on a preset management strategy.

[0026] In the embodiments of this specification, a voltage collector and a temperature collector are installed on each battery cell. The battery management system can obtain the battery information of each lithium battery cell 2 and each sodium battery cell 1 in real time through the acquisition module, and precisely control the charging and discharging process of the battery according to the preset management strategy.

[0027] Send the battery information of all the lithium battery cells 2 acquired to the battery management control unit of the lithium battery cell 2, send the battery information of all the sodium battery cells 1 acquired to the battery management control unit of the sodium battery cell 1, and connect all the acquired data to a set of battery management systems for control.

[0028] Separate the voltage acquisition wire harnesses and temperature acquisition wire harnesses of the lithium battery cell 2 and the sodium battery cell 1 to avoid interference with each other, which is convenient for the distinction and installation of the wire harnesses, can ensure the accuracy of data acquisition, and can also improve the stability and reliability of the battery management system.

[0029] Further, in the embodiments of this specification, the preset management strategy includes a normal-temperature management strategy and a low-temperature management strategy. The normal-temperature management strategy includes controlling the lithium battery cell 2 to discharge preferentially, and switching to the sodium battery cell 1 for discharge after the voltage of all the lithium battery cells 2 reaches the first preset lower limit; The low-temperature management strategy includes controlling the sodium battery cell 1 to discharge preferentially, and switching to the lithium battery cell 2 for discharge after the voltage of all the sodium battery cells 1 reaches the second preset lower limit.

[0030] In the embodiments of this specification, when the battery pack 4 is charged and discharged, the upper and lower limits of the single-cell voltage of the battery cells shall be used as the setting standard. Among them, the first preset lower limit of the single-cell voltage of the lithium battery cell 2 can be 2.5V - 2.9V, and the upper limit can be 3.6 - 3.65V. The second preset lower limit of the single-cell voltage of the sodium battery cell 1 can be 1.5V - 2.0V, and the upper limit can be 3.8 - 3.85V.

[0031] For the sake of easy understanding, an example is given where the first preset lower limit of the single-cell voltage of the lithium battery cell 2 is 2.7V, and the upper limit is 3.6V; the second preset lower limit of the single-cell voltage of the sodium battery cell 1 is 1.8V, and the upper limit is 3.85V.

[0032] In a normal-temperature environment, for example, the temperature is -10°C to 25°C, the battery management system adopts the normal-temperature management strategy. During discharge, it preferentially controls the lithium battery cell 2 to discharge. When the voltage of all the lithium battery cells 2 reaches 2.7V, it switches to the sodium battery cell 1 for discharge.

[0033] The lithium battery cell 2 discharges preferentially. Since the lithium battery cell 2 has a higher energy density, discharging preferentially in a normal-temperature environment can make more effective use of the energy of the battery pack 4. When the lithium battery cell 2 starts to discharge, the battery management system monitors the voltage change of the lithium battery cell 2 in real time. When the voltage of the lithium battery cell 2 drops to the first preset lower limit, the discharge of the lithium battery cell 2 is stopped, and it switches to the sodium battery cell 1 for discharge. The battery management system monitors the voltage change of the sodium battery cell 1 in real time. When the voltage of the sodium battery cell 1 drops to 1.8V, the discharge is stopped. By precisely controlling the charge and discharge switching points of the lithium battery cell 2 and the sodium battery cell 1, the circulation phenomenon between the two types of battery cells can be effectively avoided. At the same time, the system also sets overcharge and over-discharge protection mechanisms to ensure that the battery cells work within a safe range.

[0034] In a low-temperature environment, such as -40°C to -10°C, the battery management system adopts a low-temperature management strategy. During discharge, it preferentially controls the sodium battery cells 1 to discharge. When the voltages of all the sodium battery cells 1 reach the second preset lower limit, it switches to the lithium battery cells 2 for discharge. The low-temperature resistance performance of the sodium battery cells 1 is better than that of the lithium battery cells 2. In a low-temperature environment, preferential discharge can start the battery pack 4 faster and provide the necessary heat for it. During the discharge process of the sodium battery cells 1, the battery management system monitors the voltage change of the sodium battery cells 1 in real time. When the voltage of the sodium battery cells 1 drops to the second preset lower limit, the discharge stops and it switches to the lithium battery cells 2 for discharge. At this time, since the internal temperature of the battery pack 4 has risen, the discharge performance of the lithium battery cells 2 has also been improved. The battery management system monitors the voltage change of the lithium battery cells 2 in real time. When the voltage of the lithium battery cells 2 drops to the first preset lower limit, the discharge stops. The preferential discharge of the sodium battery cells 1 at low temperature not only provides the necessary power for the battery pack 4, but also provides a heat preservation effect for the lithium battery cells 2 through the heat generation effect during its discharge process, helping to shorten the start-up time difference of the lithium battery cells 2 in a low-temperature environment and improving the overall performance of the battery pack 4.

[0035] During charging with the normal-temperature management strategy and the low-temperature management strategy, the battery management system controls the normally open contacts of the DC contactors of the lithium battery cells 2 and the sodium battery cells 1 to close respectively, and charges the lithium battery cells 2 and the sodium battery cells 1 at the same time. When the upper limit of the single-cell voltage of the lithium battery cells 2 reaches 3.6V and the upper limit of the single-cell voltage of the sodium battery cells 1 reaches 3.85V, when the charging states of the lithium battery cells 2 and the sodium battery cells 1 each reach 100%, the lithium battery cells 2 and the sodium battery cells 1 disconnect their respective normally open contacts of the DC contactors, and the charging of the entire battery pack 4 is completed. There is a plateau period in the charge-discharge curve of the lithium battery cells 2, and the charge-discharge curve of the sodium battery cells 1 is approximately a linear curve. Therefore, the progress of the charging states of the lithium battery cells 2 and the sodium battery cells 1 reaching 100% is inconsistent. Controlling them separately by their respective DC contactors can avoid the phenomenon that the lithium battery cells 2 and the sodium battery cells 1 cannot be fully charged or overcharged.

[0036] Furthermore, the liquid-cooled battery pack based on lithium-sodium battery cells in the embodiments of this specification may further include: The first liquid-cooling plate 41 is in direct contact with the first side of the battery assembly 42 through a thermal conductive adhesive; The second liquid-cooling plate 43 is in direct contact with the second side of the battery assembly 42 through a thermal conductive adhesive; Both the first liquid-cooling plate 41 and the second liquid-cooling plate 43 are provided with a liquid inlet 412 and a liquid outlet 411.

[0037] Figure 2 It is a schematic diagram of the overall structure of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiments of this specification.

[0038] Figure 3 It is an exploded view of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiments of this specification.

[0039] In the embodiments of this specification, as Figure 2 shown, the overall battery pack 4 is a cuboid. The first liquid cooling plate 41 can serve as the bottom plate of the box body or can be installed on the inner wall of the box body bottom plate. The second liquid cooling plate 43 can serve as the top plate of the box body or can be installed on the inner wall of the box body top plate. In order to achieve a better cooling effect, the first liquid cooling plate 41 is in direct contact with the first side of the battery assembly 42 through a thermal conductive adhesive, and the second liquid cooling plate 43 is in direct contact with the second side of the battery assembly 42 through a thermal conductive adhesive.

[0040] As Figure 3 shown, both the first liquid cooling plate 41 and the second liquid cooling plate 43 are provided with a liquid inlet 412 and a liquid outlet 411. The liquid inlet 412 is used to receive the low-temperature coolant from the external coolant circulation system. The coolant enters the cooling channel inside the liquid cooling plate through the liquid inlet 412 to start its cooling cycle. The liquid outlet 411 is used to discharge the coolant heated by the battery cells. The coolant absorbs the heat generated by the battery cells during the flow inside the liquid cooling plate, and after the temperature rises, it flows out through the liquid outlet 411 and enters the external coolant circulation system for cooling and recycling.

[0041] Inside the liquid cooling plate, the coolant flows through the cooling channel, exchanges heat with the surface of the battery cells, and absorbs the heat generated by the battery cells to ensure that the battery assembly 42 always operates within a suitable temperature range.

[0042] The battery management system can adjust the working state of the coolant circulation system in real time by monitoring the temperature of the battery assembly 42. When the temperature of the battery assembly 42 rises, the flow rate and circulation speed of the coolant are increased; when the temperature of the battery assembly 42 drops, the flow rate and circulation speed of the coolant are decreased.

[0043] In order to increase the contact area between the battery assembly 42 and the liquid cooling plate, the upper and lower bottom surfaces of the lithium battery cells 2 and sodium battery cells 1 in the shape of a cuboid can be oriented towards the side surface of the box body.

[0044] In practical applications, the first liquid cooling plate 41 internally adopts a three-layer cutting brazing process to cast the fluid channel to meet the requirement of covering the contact surface of the battery assembly 42. The four sides of the liquid cooling plate are extended, which are independent and not connected to the internal fluid channel. The extended part is fixed to the box body by screws. The liquid inlet and outlet 411 are connected to the internal channel and do not interfere with the screws. The bottom of the side surface of the box body is bent and connected to the extended part around the second liquid cooling plate 43 by welding to ensure the overall protection level of the battery pack 4.

[0045] Furthermore, an external wiring port 44 is provided on the box body in the embodiments of this specification.

[0046] In the embodiments of this specification, an external wiring port 44 is provided on the side of the box body, which may include a positive and negative connector interface and an external communication debugging power supply terminal interface, facilitating the connection and operation of external devices.

[0047] In practical applications, an in-concave process can also be performed on the side of the box body to place the control module 45 of the battery management system. An external cover plate and a sealing strip are provided and fixed by screws, so that the control module 45 can be disassembled externally. The box body is provided with a handle 46, which is fixed to the box body panel by welding, facilitating the disassembly of the entire battery pack 4.

[0048] Furthermore, the liquid-cooled battery pack based on lithium-sodium battery cells in the embodiments of this specification may further include: All the lithium battery cells 2 are connected in series, and all the sodium battery cells 1 are connected in series; the positive electrodes of all the lithium battery cells 2 and the positive electrodes of all the sodium battery cells 1 are converged to the same positive copper row as the total positive electrode, and the positive electrodes of all the lithium battery cells 2 and the negative electrodes of all the sodium battery cells 1 are converged to the same negative copper row as the total negative electrode.

[0049] Figure 4 It is a schematic diagram of the electrical system of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiments of this specification.

[0050] Figure 5 It is a schematic diagram of the electrical communication of a liquid-cooled battery pack based on lithium-sodium battery cells provided by the embodiments of this specification.

[0051] In the embodiments of this specification, as Figure 4 shown, the battery assembly 42 includes 6 lithium battery cells 2 and 6 sodium battery cells 1. All the lithium battery cells 2 are connected in series, with the positive electrode of each lithium battery cell 2 connected to the negative electrode of the next lithium battery cell 2, forming a continuous circuit path. All the sodium battery cells 1 are connected in series, with the positive electrode of each sodium battery cell 1 connected to the negative electrode of the next sodium battery cell 1, forming another continuous circuit path. This connection method can ensure that all the lithium battery cells 2 and all the sodium battery cells 1 jointly bear the voltage and current during operation, improving the overall voltage output of the battery pack 4.

[0052] The charging and discharging of the lithium battery cells 2 are controlled by the first DC contactor, and the charging and discharging of the sodium battery cells 1 are controlled by the second DC contactor.

[0053] As Figure 5 shown, the positive electrodes of all the lithium battery cells 2 and the positive electrodes of all the sodium battery cells 1 are converged to the same positive copper row through a specific circuit path. This positive copper row serves as the total positive electrode of the battery pack 4 and is connected to an external load or a charging device to provide a positive current path.

[0054] The negative electrodes of all lithium battery cells 2 and the negative electrodes of all sodium battery cells 1 are also converged to the same negative copper bus through a specific circuit path. This negative copper bus serves as the total negative electrode of the battery pack 4 and is connected to an external load or charging device to provide a negative current path.

[0055] The overall circuit connection is that the lithium battery cells are connected in series to a copper bus, then through a fuse to a DC contactor, then to another copper bus, and then in series with the copper bus of the sodium battery cells. After the busbars are converged, they are connected to an external connector through a converging copper bus. The fuse protects the lithium battery cell circuit and the sodium battery cell circuit.

[0056] In practical applications, integrating the lithium battery cells 2 and the sodium battery cells 1 into the same battery pack makes up for the deficiencies of a single lithium-ion battery pack with poor low-temperature performance and a single sodium-ion battery with low energy density. At the same time, the liquid cooling component reduces the risk of battery thermal runaway and improves the overall low-temperature performance of the battery pack. The DC contactor, combined with the corresponding control strategy, solves problems such as circulating current, overcharging, and incomplete charging caused by inconsistent charging and discharging of the lithium battery cells 2 and the sodium battery cells 1, improving the overall energy utilization efficiency and providing a new direction for the integrated use of different battery cells in the new energy field.

[0057] The liquid-cooled battery pack based on lithium-sodium battery cells can have a wider operating temperature range and better low-temperature performance than current single lithium-ion battery cells. The operating temperature range of single lithium-ion battery cells is -20~60°C, and the operating temperature range of single sodium-ion battery cells is -40°C~60°C. After integrated use, the operating temperature of the liquid-cooled battery pack can reach -40°C~60°C, making it suitable for various electrical devices and energy storage systems that rely on battery modules as power sources or energy storage units.

[0058] The above describes specific embodiments of this specification, and other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired results. Additionally, the processes depicted in the drawings do not necessarily have to be performed in the specific order or continuous order shown to achieve the desired results. Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0059] It should also be noted that the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, commodity or device including a series of elements not only includes those elements but also other elements not explicitly listed, or elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, commodity or device including the said element.

[0060] The above description is only for the embodiments of this specification and is not intended to limit this application. For those skilled in the art, various changes and modifications can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims

1. A liquid-cooled battery pack based on lithium-sodium battery cells, characterized in that, Comprising: The box body main body; A battery assembly, located inside the box body main body, including a plurality of lithium battery cells and a plurality of sodium battery cells, the lithium battery cells and the sodium battery cells being arranged alternately; A liquid cooling assembly, including a first liquid cooling plate and a second liquid cooling plate, the first liquid cooling plate being located on the bottom surface of the box body main body, the second liquid cooling plate being located on the top surface of the box body main body, both the first liquid cooling plate and the second liquid cooling plate being used for heat exchange with the battery assembly.

2. The liquid-cooled battery pack based on lithium-sodium battery cells according to claim 1, wherein, Further comprising: The positive electrode directions of the lithium battery cells are arranged opposite to the positive electrode directions of the sodium battery cells.

3. The liquid-cooled battery pack based on lithium-sodium battery cells according to claim 1, characterized in that Further comprising: A battery management system, including an acquisition module for acquiring battery information of the lithium battery cells and the sodium battery cells, the acquisition module including a voltage collector and a temperature collector; Based on the voltage data acquired by the voltage collector and the temperature data acquired by the temperature collector, controlling the charging and discharging of the lithium battery cells and the charging and discharging of the sodium battery cells according to a preset management strategy.

4. The liquid-cooled battery pack based on lithium-sodium battery cells according to claim 1, wherein The preset management strategy includes a normal temperature management strategy and a low temperature management strategy. The normal temperature management strategy includes controlling the lithium battery cells to discharge preferentially, and switching to the sodium battery cells to discharge when the voltages of all the lithium battery cells reach a first preset lower limit; The low temperature management strategy includes controlling the sodium battery cells to discharge preferentially, and switching to the lithium battery cells to discharge when the voltages of all the sodium battery cells reach a second preset lower limit.

5. The liquid-cooled battery pack based on lithium-sodium battery cells according to claim 1, characterized in that, Further comprising: The first liquid cooling plate is in direct contact with the first side surface of the battery assembly through a heat-conducting adhesive; The second liquid cooling plate is in direct contact with the second side surface of the battery assembly through a heat-conducting adhesive; Both the first liquid cooling plate and the second liquid cooling plate are provided with a liquid inlet and a liquid outlet.

6. The liquid-cooled battery pack based on lithium-sodium battery cells according to claim 1, wherein, The box body main body is provided with an external wiring port.

7. The liquid-cooled battery pack based on lithium-sodium battery cells according to claim 1, wherein Further comprising: All the lithium battery cells are connected in series, and all the sodium battery cells are connected in series; the positive electrodes of all the lithium battery cells and the positive electrodes of all the sodium battery cells are converged to the same positive electrode copper row as the total positive electrode, and the positive electrodes of all the lithium battery cells and the negative electrodes of all the sodium battery cells are converged to the same negative electrode copper row as the total negative electrode.

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