Battery pack, battery pack system and battery pack management method

Abstract

This invention provides a battery pack, a battery pack system, and a battery pack management method. The battery pack consists of multiple battery cells, each cell comprising: a housing with a receiving cavity inside; a hollow shaft disposed within the receiving cavity; the hollow shaft being connected to the housing; a flow cavity within the hollow shaft; and an electrode core wound around the hollow shaft. The hollow shaft has an explosion-proof port with an explosion-proof valve installed on it. One side of the explosion-proof port communicates with the flow cavity, and the other side of the explosion-proof port is opposite to the electrode core. This invention solves the problem of low heat dissipation efficiency in existing battery packs.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more specifically, to a battery pack, a battery pack system, and a battery pack management method. Background Technology

[0002] Traditional cylindrical battery cells often suffer from insufficient support at the innermost electrode during winding, leading to the collapse of the electrode with the central hole. Traditional prismatic wound cells, lacking support at the corners during winding, frequently exhibit excessive gaps at the inner corners. Both of these winding structures result in excessive gaps between the anode and cathode, causing insufficient kinetics for lithium deposition and triggering lithium plating safety issues.

[0003] Traditional battery pack water-cooling systems are typically located at the bottom of the cells. This results in slow heat transfer on one side, low efficiency, and uneven heating of the cells, severely impacting fast-charging speed, low-temperature performance, and cell lifespan. During fast charging, the cell temperature rises, and the slow bottom-level cooling of traditional cells fails to reduce the temperature effectively.

[0004] Current cell cooling methods typically increase the cooling rate by lowering the water cooling temperature. However, this can lead to excessive temperature differences between the top and bottom of the cell, resulting in a narrow charging window at lower temperatures that causes lithium plating and limits the cell's fast-charging capability. Existing battery pack management systems also have slow heating rates, further restricting cell operation at low temperatures. Due to low heat transfer efficiency, more of the cell's energy is consumed for battery pack management, impacting cell lifespan.

[0005] In existing battery packs, the cell explosion-proof valves are prone to failure when a cell experiences thermal runaway. The valves release heat and active material, which can easily transfer to other cells. Since there is no effective heat dissipation system within the battery pack, this can easily trigger thermal runaway in other cells, leading to heat propagation throughout the pack. Furthermore, while some current safety battery packs use internal spray systems to cool the cells after thermal runaway, this method distributes the cooling water throughout the entire pack, increasing the risk of high-voltage short circuits. Summary of the Invention

[0006] The main objective of this invention is to provide a battery pack, a battery pack system, and a battery pack management method to solve the problem of low heat dissipation efficiency in existing battery packs.

[0007] To achieve the above objectives, according to a first aspect of the present invention, a battery pack is provided, comprising a plurality of battery cells, each battery cell comprising: a housing having a receiving cavity inside the housing; a hollow shaft disposed within the receiving cavity; the hollow shaft being connected to the housing; a flow cavity being disposed within the hollow shaft; and an electrode core wound around the hollow shaft; wherein, an explosion-proof port is provided on the hollow shaft, and an explosion-proof valve is installed on the explosion-proof port; one side of the explosion-proof port is in communication with the flow cavity, and the other side of the explosion-proof port is disposed opposite to the electrode core.

[0008] Further, the housing includes: an outer shell; an upper cover plate connected to the outer shell; and a lower cover plate connected to the end of the outer shell away from the upper cover plate, so that the outer shell, the upper cover plate, and the lower cover plate form a flow cavity; wherein, the hollow shaft is connected to the upper cover plate and / or the lower cover plate.

[0009] Furthermore, the upper cover plate has a first communication port communicating with the flow cavity; the lower cover plate has a second communication port communicating with the flow cavity.

[0010] Furthermore, the shell is a cuboid structure, and both the first and second connecting ports are rectangular through holes; or, the shell is a cylindrical structure, the hollow shaft is a cylindrical structure, and both the first and second connecting ports are circular through holes.

[0011] Furthermore, the battery cells are arranged sequentially along the first direction to form a battery cell array, and a connecting pipe for communicating with the flow cavity is provided between two adjacent battery cells. One end of the connecting pipe is connected to the first communication port of one of the two adjacent battery cells, and the other end of the connecting pipe is connected to the second communication port of the other of the two adjacent battery cells.

[0012] Furthermore, there are multiple cell rows arranged along a second direction, and the battery pack includes a connecting bend for connecting the flow cavities of adjacent cell rows.

[0013] Furthermore, the battery pack includes: a housing for accommodating multiple battery cells; the housing having an inlet and an outlet; an inlet pipe disposed at the inlet and communicating with the flow cavity of the battery cell; and an outlet pipe disposed at the outlet and communicating with the flow cavity of the battery cell.

[0014] According to a second aspect of the present invention, a battery pack system is provided, comprising the battery pack described above. The battery pack system includes: a cooling module for introducing cooling fluid into a flow cavity of the battery pack, the cooling module determining whether to introduce cooling fluid into the flow cavity based on the temperature of the battery cells; an explosion-proof valve warning module for detecting the status of the explosion-proof valves of the battery pack and determining whether to issue a warning based on the status of the explosion-proof valves; a thermal runaway warning module for counting the number of explosion-proof valves opened and determining whether to issue a warning based on the number of explosion-proof valves opened; and a thermal runaway prevention module, the thermal runaway prevention module being signal-connected to the thermal runaway warning module, which, when the thermal runaway warning module issues a warning, increases the flow rate of the cooling fluid in the flow cavity, causing the cooling fluid in the flow cavity to backflow into the explosion-proof port of the battery pack.

[0015] According to a third aspect of the present invention, a battery pack management method is provided, applicable to the aforementioned battery pack system. The battery pack management method includes: acquiring the temperature T of the battery cells in the battery pack, and determining whether the temperature T of the battery cells is between a first preset temperature value Td and a second preset temperature value Tg; when Td < T < Tg, introducing cooling fluid into the battery pack through a cooling module; determining whether to activate the explosion-proof valve warning based on the flow rate of the cooling fluid in the flow cavity; counting the number of explosion-proof valves opened, and calculating the number n of explosion-proof valves opened within a preset time interval, determining whether n is greater than a preset number n0; when n > n0, activating the thermal runaway warning.

[0016] Furthermore, the battery pack management method includes: when Td < T < Tg is not satisfied, calculating the rate of change of the fluid level V0 in the flow cavity, determining whether V0 is greater than the flow velocity change threshold, and opening the explosion-proof valve warning when V0 is greater than the flow velocity change threshold; counting the number of explosion-proof valves opened, and calculating the number n of explosion-proof valves opened within a preset time interval, determining whether n is greater than the preset number n0, and opening the thermal runaway warning when n > n0.

[0017] According to the technical solution of this invention, the battery pack is composed of multiple battery cells. Each battery cell includes: a housing with a receiving cavity inside; a hollow shaft disposed within the receiving cavity; the hollow shaft being connected to the housing; a flow cavity within the hollow shaft; and an electrode core wound around the hollow shaft. The hollow shaft has an explosion-proof port with an explosion-proof valve installed on it. One side of the explosion-proof port communicates with the flow cavity, and the other side is positioned opposite the electrode core. By employing this configuration, placing the hollow shaft within the housing and winding the electrode core around it, the hollow shaft can provide support for the battery cell, thus solving the problem of low heat dissipation efficiency in existing battery packs. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 An exploded structural schematic diagram of a cell in a battery pack according to the present invention is shown;

[0020] Figure 2 It shows Figure 1 A schematic diagram of the structure of a cell in an embodiment of the battery pack of the present invention;

[0021] Figure 3 It shows Figure 1 A top view of an embodiment of the battery cell of the battery pack of the present invention;

[0022] Figure 4 It shows Figure 3 A cross-sectional view of the AA portion of the battery cell in the battery pack of the present invention;

[0023] Figure 5 It shows Figure 1 A bottom view of an embodiment of the battery cell of the battery pack of the present invention;

[0024] Figure 6 A schematic diagram of another embodiment of the battery pack of the present invention is shown;

[0025] Figure 7 It shows Figure 6 Internal cross-sectional view of the battery pack of the present invention;

[0026] Figure 8 It shows Figure 6 A schematic diagram of the internal structure of the battery pack of the present invention;

[0027] Figure 9 A schematic diagram of an embodiment of the battery pack of the present invention is shown;

[0028] Figure 10 It shows Figure 9 A cross-sectional view of the BB portion of the battery pack of the present invention;

[0029] Figure 11 A test diagram of the battery pack of the present invention is shown;

[0030] Figure 12 The present invention is shown Figure 11 A cross-sectional view of the CC section of the battery pack;

[0031] Figure 13 , Figure 14 A flowchart illustrating the battery pack management method of the present invention is shown.

[0032] The above figures include the following reference numerals:

[0033] 1. Battery cell; 11. Housing; 111. Outer shell; 112. Upper cover plate; 113. Lower cover plate; 114. First connecting port; 115. Second connecting port; 12. Hollow shaft; 121. Flow cavity; 122. Explosion-proof port; 13. Electrode core;

[0034] 3. Connecting bend; 4. Connecting pipe; 5. Box body; 51. Inlet; 52. Outlet; 6. Liquid inlet pipe; 7. Liquid outlet pipe; 10. Explosion-proof valve. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] See Figures 1 to 14 The battery pack of this embodiment is composed of multiple battery cells 1. Each battery cell 1 includes a housing 11 with a receiving cavity inside; a hollow shaft 12 disposed within the receiving cavity; the hollow shaft 12 connected to the housing 11; and a flow cavity 121 within the hollow shaft 12; and an electrode core 13 wound around the hollow shaft 12. The hollow shaft 12 has an explosion-proof port 122, on which an explosion-proof valve 10 is installed. One side of the explosion-proof port 122 communicates with the flow cavity 121, and the other side of the explosion-proof port 122 is opposite to the electrode core 13. With this configuration, the hollow shaft 12 is placed inside the housing 11, and the electrode core 13 is wound around it, allowing the hollow shaft 12 to support the electrode core 13. A cooling device can be installed inside the hollow shaft 12, enabling the battery pack to be cooled from within the battery cells 1, thus improving cooling efficiency and solving the problem of low heat dissipation efficiency in existing battery packs.

[0037] In some embodiments, the material of the housing 11 may be one or more of steel, aluminum or other metals or plastics.

[0038] The battery pack of the present invention can solve the problems of insufficient support and collapse of the innermost electrode of the existing wound structure cell 1, and excessive gap between the innermost anode and cathode. For example, the collapse of the center hole of the cylindrical cell 1 and the large gap between the innermost corner electrode of the prismatic cell 1 lead to insufficient local dynamics and lithium deposition, causing safety problems.

[0039] In some embodiments, the battery pack uses square-shell cells. When winding the square-shell cells, the winding needle needs to be pulled out after winding is completed. The core is relatively fluffy and requires an additional hot pressing process, which can improve production efficiency.

[0040] In some embodiments, the outer layer of the built-in hollow shaft 12 is provided with an insulating spray, a thermally conductive material, and a corrosion-resistant coating. The spray material includes, but is not limited to, resin materials, including one or a combination of at least two of phenolic resin, polyester resin, polyamide resin, and polyvinyl chloride resin. The thermally conductive material includes at least one of boron nitride, aluminum nitride, silicon carbide, silicon nitride, aluminum oxide, gallium nitride, gallium arsenide, gallium phosphide, zinc oxide, indium phosphide, beryllium oxide, magnesium oxide, and magnesium silicon nitride, which can effectively improve the thermal conductivity between the battery and cooling water. The outer corrosion-resistant coating is made of PTFE emulsion or PFA emulsion, which can effectively prevent the electrolyte, cooling water, etc. from corroding the inner wall of the battery casing and the insulating coating.

[0041] In some embodiments, the battery electrode is a wound structure, with the built-in hollow shaft 12 acting as a winding needle to wind the electrode on the built-in hollow shaft 12.

[0042] In some embodiments, the thickness of the outer shell and the thickness of the built-in hollow shaft 12 are 0.1 mm to 2 mm.

[0043] In the battery pack of this embodiment, see Figures 1 to 10 The housing 11 includes: an outer shell 111, an upper cover plate 112 connected to the outer shell 111; and a lower cover plate 113 connected to the end of the outer shell 111 away from the upper cover plate 112, so that the outer shell 111, the upper cover plate 112 and the lower cover plate 113 form a flow cavity 121; wherein, the hollow shaft 12 is connected to the upper cover plate 112 and / or the lower cover plate 113.

[0044] See Figures 1 to 12 In the battery pack of this embodiment, the upper cover plate 112 has a first communication port 114 communicating with the flow cavity 121; the lower cover plate 113 has a second communication port 115 communicating with the flow cavity 121.

[0045] In the battery pack of this embodiment, see Figures 1 to 10 The shell 11 has a cuboid structure, and the first connecting port 114 and the second connecting port 115 are both rectangular through holes; or, the shell 11 has a cylindrical structure, the hollow shaft 12 has a cylindrical structure, and the first connecting port 114 and the second connecting port 115 are both circular through holes.

[0046] In some embodiments, the outer layer of the housing 11 can be circular or square. When the outer layer is circular, the internal hollow shaft 12 is concentric with the outer layer. When the outer layer is square, the internal hollow shaft 12 is elliptical.

[0047] See Figures 1 to 10 In the battery pack of this embodiment, the cells 1 are arranged sequentially along the first direction to form a cell array. A connecting pipe 4 for communicating with the flow cavity 121 is provided between two adjacent cells 1. One end of the connecting pipe 4 is connected to the first communication port 114 of one of the two adjacent cells 1, and the other end of the connecting pipe 4 is connected to the second communication port 115 of the other of the two adjacent cells 1.

[0048] In some embodiments, the battery pack uses the hollow shell cell 1 described above, with the inner shell of cell 1 serving as a water-cooling pipe to achieve heat transfer from all four sides, thereby improving the heat transfer rate, heat transfer efficiency, and heat transfer uniformity.

[0049] In the battery pack of this embodiment, see Figures 1 to 10The battery pack includes multiple cell rows arranged along a second direction. The battery pack includes a connecting bend 3, which is used to connect the flow cavity 121 of adjacent cell rows.

[0050] See Figures 9 to 12 In this embodiment, the battery pack includes: a housing 5 for accommodating multiple battery cells 1; the housing 5 has an inlet 51 and an outlet 52; an inlet pipe 6 disposed on the inlet 51 and communicating with the flow cavity 121 of the battery cell 1; and an outlet pipe 7 disposed on the outlet 52 and communicating with the flow cavity 121 of the battery cell 1.

[0051] In the battery pack of this embodiment, see Figures 9 to 12 The extension direction of the flow cavity 121 is perpendicular to the extension direction of the explosion-proof port 122; and / or, there are multiple explosion-proof ports 122, which are arranged at intervals.

[0052] Specifically, the battery explosion-proof valve 10 is placed inside the hollow shaft 12. There can be multiple explosion-proof valves 10. The number and area of ​​the explosion-proof valves 10 can be increased to adapt to the explosion-proof pressure of different systems.

[0053] In some embodiments, the battery pack is composed of the aforementioned battery cells 1. The hollow spaces between the battery cells 1 are connected by connecting pipes 4. The hollow shaft 12 inside the battery cell 1 serves as the cooling water channel for the battery pack. The battery cells 1 are connected to each other by short water-cooling pipes. Multiple water level sensors and flow meters are installed inside the water-cooling pipes of the battery pack. The battery cells 1 have heat transfer on all four sides, which can significantly improve the heat transfer rate and efficiency, and the battery cells 1 are heated evenly. The efficient battery pack management system can solve the problems of excessively rapid temperature rise of the battery cells 1 during fast charging and slow preheating in low-temperature environments. It can also reduce the power consumption of the battery cells 1 for battery pack management and improve the service life of the battery cells 1. An explosion-proof valve 10 is opened inside the hollow aluminum shaft of the battery cell 1. When the battery cell 1 experiences thermal runaway, the explosion-proof valve 10 opens, and the active material can be directionally sprayed into the cooling water inside the hollow shaft 12 to achieve rapid cooling without falling to other battery cells 1 and causing heat spread.

[0054] The battery pack system of this embodiment includes the battery pack described above. The battery pack system includes: a cooling module, which is used to introduce cooling fluid into the flow cavity 121 of the battery pack, and the cooling module determines whether to introduce cooling fluid into the flow cavity 121 based on the temperature of the battery cell 1 of the battery pack; an explosion-proof valve warning module, which is used to detect the state of the explosion-proof valve 10 of the battery pack, and determines whether to issue a warning based on the state of the explosion-proof valve 10; a thermal runaway warning module, which is used to count the number of explosion-proof valves 10 that are opened, and determines whether to issue a warning based on the number of explosion-proof valves 10 that are opened; and a thermal runaway prevention module, which is signal-connected to the thermal runaway warning module. When the thermal runaway warning module issues a warning, it increases the flow rate of the cooling fluid in the flow cavity 121, causing the cooling fluid in the flow cavity 121 to flow back into the explosion-proof port 122 of the battery pack.

[0055] See Figure 13 , Figure 14 The battery pack management method of this embodiment is applicable to the above-mentioned battery pack system. The battery pack management method includes: collecting the temperature T of the battery cell in the battery pack and determining whether the temperature T of the battery cell is between a first preset temperature value Td and a second preset temperature value Tg; when Td < T < Tg, introducing cooling fluid into the battery pack through the cooling module; determining whether to activate the explosion-proof valve warning based on the flow rate of the cooling fluid in the flow cavity 121; counting the number of explosion-proof valves 10 that are opened and calculating the number n of explosion-proof valves 10 that are opened within a preset time interval, determining whether n is greater than a preset number n0, and activating the thermal runaway warning when n > n0.

[0056] Specifically, the method for determining whether to open the explosion-proof valve for early warning based on the flow rate of the cooling fluid in the flow chamber 121 is as follows: when the cooling module closes the cooling pipes, the rate of change of the water level V0 in the cooling pipes is calculated, and it is determined whether V0 is greater than the flow rate change threshold. If V0 is greater than the flow rate change threshold, the explosion-proof valve 10 is opened. Otherwise, the rate of change of the water level V0 in the cooling pipes is calculated again.

[0057] Specifically, the method for measuring V0 is to collect the current water level h0 in the cooling pipe, measure the water level h1 again after t seconds, and take the difference between h0 and h1, V0=|h1-h0| / t.

[0058] See Figure 13 , Figure 14When Td < T < Tg is not satisfied, the battery pack management method includes: calculating the rate of change of the water level in the flow cavity 121, determining whether the rate of change is greater than the flow rate change threshold, and opening the explosion-proof valve warning when the rate of change is greater than the flow rate change threshold; counting the number of explosion-proof valves 10 opened, and calculating the number n of explosion-proof valves 10 opened within a preset time interval, determining whether n is greater than the preset number n0, and opening the thermal runaway warning when n > n0.

[0059] Specifically, when Td < T < Tg is not satisfied, the flow rate Vg of the cooling fluid in the flow chamber 121 is collected, and the flow rate Vz at the water pump rotor of the cooling module is collected. It is then determined whether the difference between the flow rate Vg of the cooling fluid in the flow chamber 121 and the flow rate Vz at the water pump rotor of the cooling module is greater than a preset flow rate threshold. When the difference between the flow rate Vg of the cooling fluid in the flow chamber 121 and the flow rate Vz at the water pump rotor of the cooling module is greater than the preset flow rate threshold, the explosion-proof valve is activated for early warning.

[0060] In some embodiments, when the thermal runaway warning is activated, the flow rate of the cooling fluid in the cooling pipe is increased, accelerating the backflow of cooling fluid into the battery cell, causing the open-valve battery cell to deactivate.

[0061] The explosion-proof valve opening warning method in this embodiment includes multiple cooling water level acquisition devices built into the water-cooling pipes of the battery pack. A safety warning will be issued when the cooling water level drops rapidly. A thermal propagation protection method is also provided: when thermal runaway occurs in the battery pack and the explosion-proof valve cracks at the marked location, a water pump can accelerate the cooling water flow rate, rapidly channeling the cooling water into the battery cell 1 to prevent thermal propagation.

[0062] The method for preparing the battery pack in this embodiment is as follows:

[0063] Using the hollow shaft 12 as a winding needle for the battery cell 1, the positive and negative electrode plates and the separator of the battery cell 1 are wound onto the hollow shaft 12 to form the electrode core 13, with the positive and negative electrode tabs exiting from both sides respectively.

[0064] The outer shell is fitted into the pole core.

[0065] The positive and negative electrode tabs are welded to the cover plate respectively.

[0066] The two cover plates are welded to the outer shell and the hollow shaft 12 to form a battery.

[0067] This preparation method is not a limitation of the invention, but only provides a solution. It can also be a method with same-side tabs, stacked structure, etc.

[0068] Example 1:

[0069] The battery pack of this embodiment is applicable to both cylindrical and prismatic cells 1, solving the problem of central hole collapse in cylindrical cells 1; reducing the problem of lithium plating during cycling caused by excessively large innermost corners in prismatic wound cells 1; the built-in hollow shaft 12 is coated with insulating material and thermally conductive material is added to increase heat transfer plastic; an explosion-proof valve is installed inside the hollow shaft 12, and the required burst pressure of the explosion-proof valve is selected according to the cell 1 system; the built-in hollow shaft 12 can be used as a winding needle for winding cells 1, and the winding needle does not need to be pulled out after winding, and the formed core does not need to be hot-pressed, thus improving the production efficiency of cells 1.

[0070] Example 2:

[0071] In this embodiment, the explosion-proof valve 10 is built into the hollow shaft 12 of the battery cell 1, facing the cooling water.

[0072] By utilizing the structure of cell 1, when cell 1 experiences thermal runaway, the explosion-proof valve can prevent active materials from falling to other high-voltage locations and causing high-voltage ignition and thermal runaway. Combining cell 1 with the water-cooling pipe eliminates the need for bottom water-cooling space and increases energy density.

[0073] The above settings can solve the problem that when the explosion-proof valve of the current cell 1 is facing upwards, the active material sprayed out when the cell 1 experiences thermal runaway and the valve is blown off falls onto the high-voltage connection, causing high-voltage sparking and triggering thermal runaway of the battery pack.

[0074] Example 3:

[0075] The method for detecting the pressure opening of the explosion-proof valve in this embodiment uses a built-in water level monitoring device in the cooling water pipeline to determine whether the explosion-proof valve 10 of the battery cell 1 has cracked by monitoring the rate of decrease in the cooling water level.

[0076] Example 4:

[0077] The battery pack has the following thermal runaway protection system. When thermal runaway occurs, the battery management system activates the cooling water system, increases the water pump speed, and uses the cooling water to quickly backflow the cooling water to the spray valve cell 1, thereby reducing the temperature of cell 1 and preventing heat spread.

[0078] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0079] The battery pack of the present invention solves the technical problem of lithium plating due to the collapse of the inner electrode sheet of the wound-structured battery cell 1, as described above in the art. The present invention also provides a battery pack with rapid heat transfer and no heat propagation, solving the technical problem of slow thermal regulation speed of large battery cells 1, expanding the fast charging and low-temperature operation conditions of battery cells 1, and simultaneously solving the technical problem of heat propagation caused by the inability to dissipate heat during thermal runaway of battery cells 1. The present invention also provides a method for early warning of the opening of the explosion-proof valve of battery cells 1, solving corrosion and safety problems caused by sealing failure of battery cells 1.

[0080] The battery pack of the present invention includes a hollow aluminum shaft 12, with an explosion-proof valve built into the hollow shaft 12, wound electrode sheets, etc. It supports the inner electrode sheets of the wound cell 1, solving the problem of lithium deposition due to inner electrode sheet collapse.

[0081] In the battery pack of this invention, the hollow shafts 12 of each cell 1 can be interconnected to form a water-cooling pipeline, which significantly improves heat transfer efficiency. The explosion-proof valve of cell 1 is located adjacent to the cooling water; in the event of thermal runaway of cell 1, the active material is ejected in a directional manner, rapidly cooling the battery pack and preventing heat spread. This battery pack structure enables early warning of explosion-proof valve pressure opening. When the explosion-proof valve of cell 1 ruptures, cooling water rushes into cell 1, quickly causing the active material inside cell 1 to fail, thus preventing safety issues. Simultaneously, the battery management system can monitor changes in the cooling water level for timely warnings.

[0082] Compared to existing wound structures, the battery pack of the present invention can significantly reduce the probability of lithium plating due to inner electrode collapse.

[0083] Compared to existing winding structures, the battery pack of the present invention can reduce the need for pulling out winding needles and hot pressing processes, thereby improving production efficiency and reducing production costs.

[0084] Compared with existing battery pack management systems, the battery pack of this invention can significantly improve the heat transfer rate and heat transfer efficiency.

[0085] The battery pack of the present invention addresses the problem that the market cannot detect the opening of the explosion-proof valve. The present invention can effectively detect the pressure opening of the explosion-proof valve and deactivate the opening valve cell 1, thereby avoiding safety risks.

[0086] Compared to existing battery pack designs, the battery pack of this invention features a built-in explosion-proof valve positioned directly opposite the cooling water, which significantly improves safety performance.

[0087] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0088] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0089] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0090] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0091] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery pack comprising a plurality of battery cells (1), characterized in that, The battery cell (1) includes: The housing (11) has a receiving cavity inside; A hollow shaft (12) is disposed in the receiving cavity; the hollow shaft (12) is connected to the housing (11); the hollow shaft (12) has a flow cavity (121). The pole core (13) is wound around the hollow shaft (12); The hollow shaft (12) is provided with an explosion-proof port (122), and an explosion-proof valve (10) is installed on the explosion-proof port (122); one side of the explosion-proof port (122) is connected to the flow cavity (121), and the other side of the explosion-proof port (122) is opposite to the pole core (13); The battery cells (1) are arranged sequentially along a first direction to form a battery cell array. A connecting pipe (4) is provided between two adjacent battery cells (1) for communicating with the flow cavity (121). One end of the connecting pipe (4) is connected to the flow cavity (121) of one of the two adjacent battery cells (1), and the other end of the connecting pipe (4) is connected to the flow cavity (121) of the other of the two adjacent battery cells (1). The connecting pipe (4) connects the flow cavities (121) of the adjacent battery cells (1) in series to form a continuous cooling channel, so that the cooling fluid can flow through the interior of each battery cell (1) in sequence. The battery pack comprises multiple cell rows, which are arranged along a second direction. The battery pack includes a connecting bend (3) for connecting the flow cavities (121) of adjacent cell rows. When the battery cell (1) experiences thermal runaway, the explosion-proof valve (10) opens, and the active material in the battery cell (1) is ejected through the explosion-proof port (122) into the cooling fluid in the flow chamber (121); then, by increasing the flow rate of the cooling fluid, the cooling fluid in the flow chamber (121) is backflowed into the explosion-proof port (122) of the battery cell (1) to cool the battery cell (1).

2. The battery pack according to claim 1, characterized in that, The housing (11) includes: Outer shell (111); The upper cover plate (112) is connected to the outer shell (111); The lower cover plate (113) is connected to the end of the outer shell (111) away from the upper cover plate (112) so that the outer shell (111), the upper cover plate (112) and the lower cover plate (113) form the flow cavity (121). The hollow shaft (12) is connected to the upper cover plate (112) and / or the lower cover plate (113).

3. The battery pack according to claim 2, characterized in that, The upper cover plate (112) has a first communication port (114) communicating with the flow cavity (121). The lower cover plate (113) has a second communication port (115) that communicates with the flow cavity (121).

4. The battery pack according to claim 3, characterized in that, The shell (11) has a cuboid structure, and both the first connecting port (114) and the second connecting port (115) are rectangular through holes; or, The shell (11) is a cylindrical structure, the hollow shaft (12) is a cylindrical structure, and the first connecting port (114) and the second connecting port (115) are both circular through holes.

5. The battery pack according to claim 3, characterized in that, The battery pack includes: A housing (5) for accommodating a plurality of said battery cells (1); the housing (5) has an inlet (51) and an outlet (52); Liquid inlet pipe (6), the liquid inlet pipe (6) is disposed on the inlet (51), and the liquid inlet pipe (6) is connected to the flow cavity (121) of the battery cell (1); The liquid outlet pipe (7) is provided on the liquid inlet pipe (6) and the liquid outlet pipe (52) is connected to the flow cavity (121) of the battery cell (1).

6. A battery pack system comprising the battery pack according to any one of claims 1 to 5, characterized in that, The battery pack system includes: A cooling module is used to introduce cooling fluid into the flow cavity (121) of the battery pack. The cooling module determines whether to introduce cooling fluid into the flow cavity (121) based on the temperature of the battery cell (1) of the battery pack. An explosion-proof valve warning module is used to detect the status of the explosion-proof valve (10) of the battery pack and to determine whether to issue a warning based on the status of the explosion-proof valve (10). Thermal runaway early warning module, the thermal runaway early warning module is used to count the number of times the explosion-proof valve (10) is opened, and decide whether to issue an early warning based on the number of times the explosion-proof valve (10) is opened; Thermal runaway prevention module, which is signal-connected to thermal runaway warning module, increases the flow rate of cooling fluid in the flow cavity (121) when the thermal runaway warning module issues a warning, so that the cooling fluid in the flow cavity (121) flows back into the explosion-proof port (122) of the battery pack.

7. A battery pack management method, applicable to the battery pack system of claim 6, characterized in that, The battery pack management method includes: The temperature T of the battery cells in the battery pack is collected, and it is determined whether the temperature T of the battery cells is between a first preset temperature value Td and a second preset temperature value Tg; when Td < T < Tg, cooling fluid is introduced into the battery pack through the cooling module. Whether to open the explosion-proof valve for early warning is determined based on the flow rate of the cooling fluid in the flow cavity (121); The number of explosion-proof valves (10) opened is counted, and the number n of the number of explosion-proof valves (10) opened within a preset time interval is calculated. It is determined whether n is greater than the preset number n0. When n>n0, a thermal runaway warning is activated.

8. The battery pack management method according to claim 7, characterized in that, The battery pack management method includes: When Td < T < Tg is not satisfied, calculate the rate of change of the water level V0 of the fluid in the flow cavity (121), determine whether V0 is greater than the flow velocity change threshold, and when V0 is greater than the flow velocity change threshold, open the explosion-proof valve for early warning. The number of explosion-proof valves (10) opened is counted, and the number n of the number of explosion-proof valves (10) opened within a preset time interval is calculated. It is determined whether n is greater than the preset number n0. When n>n0, a thermal runaway warning is activated.

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