Battery pack lower box, battery pack and vehicle

Abstract

The battery pack lower box provided by the present disclosure comprises a side beam frame, a bottom guard plate and an internal cross beam, the side beam frame has an air inlet hole, an air outlet passage and an air outlet hole, the air inlet hole is communicated with the air outlet hole through the air outlet passage, the air outlet hole is used for discharging the air and fire flowing to the air outlet hole through the air outlet passage out of the lower box body, and the internal cross beam has a groove and / or a notch arranged at the end portion, the groove and the notch communicate adjacent battery accommodating cavities. The battery pack lower box of the present disclosure can reduce the damage of the local high temperature in a certain battery accommodating cavity to the box body or the heat runaway diffusion caused by the local high temperature of a certain battery, and prevent the explosion after the heat runaway of the battery.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and in particular to a battery pack housing, a battery pack, and a vehicle. Background Technology

[0002] With the government's planning and support for the development of the new energy vehicle industry, electric vehicles are becoming increasingly popular. However, battery safety has become a major pain point for the industry. From 2019 to the end of 2020, there were more than 100 cases of electric vehicle fires caused by battery thermal runaway. In 2020, the national mandatory standard GB 38031-2020, "Safety Requirements for Power Batteries for Electric Vehicles," was issued. The standard clearly requires that the battery pack should provide alarms and protection 5 minutes before thermal runaway of a single battery causes heat diffusion and leads to danger in the passenger compartment. The technology to prevent battery pack thermal runaway from catching fire or exploding has become a solution to the industry's pain point and challenge. Summary of the Invention

[0003] In view of this, the present disclosure aims to propose a battery pack and lower housing, which adopts a commutation heat dissipation design to achieve a balance of internal pressure and temperature of the battery pack, and reduces the temperature of the directional explosion inlet by uniformly dissipating and reducing heat. The lower housing can improve the safety of the battery pack and reduce the risk of thermal runaway explosion and fire.

[0004] To achieve the above objectives, the technical solution disclosed herein is implemented as follows:

[0005] This disclosure proposes a lower housing for a battery pack, including a lower housing body. The lower housing body includes a side beam frame, a bottom protective plate, and an internal crossbeam. The internal crossbeam divides the lower housing body into multiple battery receiving cavities for accommodating battery modules. The side beam frame has an air inlet, an exhaust channel, and an exhaust hole. The air inlet communicates with the exhaust hole through the exhaust channel. The air inlet is used to introduce the gas flow generated during thermal runaway of the battery module into the exhaust channel. The exhaust hole is used to discharge the gas flow that flows through the exhaust channel to the exhaust hole from the lower housing body. The internal crossbeam has a groove and / or a notch at its end, and the groove and the notch connect adjacent battery receiving cavities.

[0006] Furthermore, the notch is located at the upper part of the end of the inner crossbeam.

[0007] Furthermore, the internal crossbeam is provided with a plurality of mounting points, which are used to connect to the top cover of the battery pack, and the groove is spaced apart from the mounting points.

[0008] Furthermore, the battery module within the battery housing cavity includes the protective cover, and the lower edge of the groove is higher than the height of the protective cover of the battery module.

[0009] Furthermore, the opening area of ​​several of the grooves gradually decreases from both ends of the inner crossbeam toward the middle.

[0010] Furthermore, the bottom of the battery module is provided with a liquid cooling plate, which is integrated inside the lower housing body. The heat exchange channel formed between the liquid cooling plate and the bottom protective plate is connected to the exhaust channel. Several recesses are formed at the end of the liquid cooling plate to form a heat exchange channel between the upper space of the liquid cooling plate and the lower space of the liquid cooling plate, which can realize gas exchange.

[0011] Furthermore, the bottom of the battery module is provided with a liquid cooling plate, which is integrated inside the lower housing body. The heat exchange channel formed between the liquid cooling plate and the bottom protective plate is connected to the exhaust channel. A through hole is formed on the middle surface of the liquid cooling plate, forming a heat exchange channel between the upper space of the liquid cooling plate and the lower space of the liquid cooling plate, which can realize gas exchange.

[0012] Furthermore, the through holes of the liquid cooling plate are located at the centerline of the liquid cooling plate.

[0013] Furthermore, the through holes of the liquid cooling plate are oblong.

[0014] This disclosure also proposes a battery pack using the aforementioned battery pack lower housing.

[0015] This disclosure also proposes a vehicle that uses the aforementioned battery pack.

[0016] Compared with the prior art, the battery pack lower housing described in this disclosure has the following advantages:

[0017] The battery pack described in this disclosure employs a commutation heat dissipation structure design, with commutation heat dissipation channels located at the bottom of the liquid cooling plate and the top of the module. These channels surround the module 360° in the ZY direction, achieving heat equalization and dissipation. In the XY direction, the commutation heat dissipation channels connect to several battery housing cavities, further equalizing the heat and reducing the pressure and temperature within the battery housing cavities of the thermal runaway module. This heat equalization and dissipation lowers the temperature of the directional explosion inlet. Compared to existing technologies, the battery pack described in this disclosure offers higher safety and greater assurance, reducing the risk of thermal runaway explosion and fire. Attached Figure Description

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

[0019] Figure 1 This is an exploded view of the battery pack described in the embodiments of this disclosure;

[0020] Figure 2 This is a schematic diagram of the lower housing of the battery pack according to an embodiment of this disclosure;

[0021] Figure 3 This is a schematic diagram of the Y-direction section of the side beam described in this embodiment of the invention;

[0022] Figure 4 This is a schematic diagram of the air inlet of the side beam according to the embodiments of this disclosure;

[0023] Figure 5 yes Figure 2 A magnified view of a section at point A in the middle;

[0024] Figure 6 yes Figure 2 A magnified view of a section at point B in the middle;

[0025] Figure 7 yes Figure 2 A magnified view of a section at point C;

[0026] Figure 8 This is a schematic diagram of the Y-direction cross-section of the battery pack according to an embodiment of this disclosure;

[0027] Figure 9 yes Figure 8 A magnified view of a section at point F in the middle;

[0028] Figure 10 This is a schematic diagram of the converter path described in the embodiments of this disclosure.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Battery pack lower casing; 2. Battery module; 3. High and low voltage electrical components; 4. Top cover; 5. Main exhaust device; 6. Secondary exhaust device; 100. Lower casing body; 10. Side beam frame; 11. Side beam; 12. End crossbeam; 13. Protruding side beam; 14. Protruding crossbeam; 15. Internal crossbeam; 16. Bottom guard plate; 17. Liquid cooling plate; 111. Air inlet; 112. Exhaust channel; 151. Mounting point; 152. Recess; 211. Battery cell; 212. Thermal insulation material; 213. Busbar; 22. Protective cover; 101, 102, 103, 104, 105, 106. Detailed Implementation

[0031] To make the technical problems, technical solutions, and beneficial effects to be solved by this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this disclosure and are not intended to limit it. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0032] It should be noted that, in this disclosure, the term "front" refers to the direction from the rear of the vehicle to the front, and vice versa; the front-to-back direction is parallel to the X-axis. The term "up" refers to the direction from the bottom of the vehicle to the roof, and vice versa; the up-down direction is parallel to the Z-axis. Furthermore, the reference to "parallel to the X-axis," "Z-axis," and "Y-axis" in this disclosure can be completely parallel to the X-axis, Z-axis, and Y-axis, or approximately parallel to the X-axis, Z-axis, and Y-axis. The description of being perpendicular to the X-axis, Z-axis, and Y-axis is similar to the aforementioned description of parallelism and will not be repeated here. The description of being along the X-axis, Z-axis, and Y-axis is similar to the aforementioned description of parallelism and will not be repeated here.

[0033] The following will refer to the appendix. Figure 1-10 This disclosure will be described in detail with reference to its implementation methods.

[0034] Reference Figure 1 As shown, this disclosure provides a lower housing 1 for a battery pack and a battery pack having the lower housing 1. The battery pack mainly includes the lower housing 1, a battery module 2, high and low voltage electrical components 3, and a top cover 4.

[0035] The top cover 4 and the lower battery pack housing 1 are sealed together. Several battery modules 2 are housed in the space formed by the connection between the top cover 4 and the lower battery pack housing 1. Each battery module 2 includes several individual battery cells 211 and a protective cover 22. The protective cover 22 is provided with an explosion-proof vent. The top cover 4 is preferably made of high-strength, high-temperature resistant material using a stamping process to prevent premature failure of the top cover in the event of battery thermal runaway, and to prevent harmful gases or flames from being ejected upwards into the cabin, thus avoiding personal safety accidents.

[0036] like Figure 2 As shown, the lower housing 1 of the battery pack includes a lower housing body 100, which includes a side beam frame 10, a bottom protective plate 16, and an internal crossbeam 15. The side beam frame 10 includes a side beam 11 and an end crossbeam 12. In some embodiments, both the upper cover 4 and the lower housing 1 have protrusions in plan view, and the protrusions of the upper cover 4 and the lower housing 1 cooperate with each other to form a space for accommodating high and low voltage electrical components 3. The side beam frame 10 includes a side beam 11, an end crossbeam 12, a protruding side beam 13, and a protruding crossbeam 14.

[0037] The internal cross beam 15 divides the side beam frame 10 into several battery accommodation cavities for arranging the battery modules 2 and other components. The battery accommodation cavities can be designed for expansion according to actual needs. The number and size of the battery accommodation cavities can be adjusted according to the actual project. One independent battery accommodation cavity can arrange one, two or more battery modules 2. The internal cross beam 15 plays a role of physical isolation between the battery accommodation cavities. If thermal runaway occurs in a single battery accommodation cavity, it can prevent the gas and fire flow generated after thermal runaway from forming a serious cross flow in the battery pack and causing the spread of thermal runaway.

[0038] In some embodiments, as Figure 9 shown, the battery module 2 is stacked by a plurality of cell monomers 211 and a plurality of high-temperature resistant, impact-resistant and heat-insulating materials 212, and includes a bus bar 213 and a monomer acquisition component at the top. The bus bar 213 is connected to the output pole of the cell monomer 211 by a laser welding process. The cell monomer 211 includes an explosion-proof valve (not shown in the figure) for relieving pressure after the thermal runaway of the cell monomer 211. The protective cover 22 is provided with an explosion vent, and the explosion vent is disposed opposite to the explosion-proof valve for discharging the gas and fire flow generated by the thermal runaway battery outward and reducing the residual temperature of the thermal runaway.

[0039] The side beam frames 10 all adopt a hollow cavity structure. By splicing the side beam frames 10, a sealed and continuous exhaust channel is formed. The exhaust channel can be divided into one or more layers in the Z direction in the cavity of the side beam frame 10. In some embodiments, reinforcing ribs are provided in the hollow cavity of the side beam frame 10, and exhaust channels with different numbers can be realized. Exhaust channels with different numbers and cross-sectional shapes are within the scope of consideration of the present disclosure, such as "day" character cross-section, "field" character cross-section, etc. The present disclosure takes the "eye" character type with three exhaust channels as an example for illustration, as Figure 3 shown. Taking the side beam 11 as an example, the side beam 11 is divided into a top-layer exhaust channel 112a, a middle-layer exhaust channel 112b, and a bottom-layer exhaust channel 112c.

[0040] In some embodiments, as Figure 4 shown, the side beam 11 and the side of the battery compartment are provided with a plurality of air inlet holes 111. The air inlet holes 111 are communicated with the exhaust channels 112. Exhaust channels with different numbers and shapes are within the scope of consideration of the present disclosure. In some embodiments, to achieve the heat flow distribution of the gas and fire flow, the air inlet holes 111 can be divided into multiple layers in the Z direction, and the number of layers of the air inlet holes 111 is greater than or equal to the number of layers of the exhaust channels 112, that is, each exhaust channel 112 corresponds to at least one layer of air inlet holes 111. Taking the "eye" character type with three exhaust channels as an example, as Figure 4 shown, the top-layer air inlet hole 111a is communicated with the top-layer exhaust channel 112a, the middle-layer air inlet hole 111b is communicated with the middle-layer exhaust channel 112b, and the bottom-layer air inlet hole 111 is communicated with the bottom-layer exhaust channel 112c.

[0041] In some embodiments, the design of the air inlet 111 is not limited to the circular structure shown in this disclosure, but can be oblong, quadrilateral, hexagonal, octagonal, etc. The position of the exhaust port 111 is evenly arranged according to the principle of balanced flow distribution to prevent exhaust dead zones.

[0042] In some embodiments, the top-level air inlet 111a corresponding to the top-level exhaust channel 112a closest to the top cover 4 adopts a distributed small hole design. The number of corresponding top-level air inlets 111a in each battery housing cavity is no less than two, preventing the side beam frame 10 from being damaged by impact in the event of thermal runaway of a battery module 2. The number of air inlets 111a is not limited to the two shown in the illustration; the illustration is merely illustrative, and there can be more air inlets. For different design configurations of the battery module 2, each layer of air inlets 111 can be designed with multiple holes, but the number of air inlets 111a connected to the top-level exhaust channel 112a is at least not less than the number of air inlets 111 connected to each of the lower exhaust channels 112.

[0043] In some implementations, in order to balance the flow of the air inlet 111 and achieve the function of rapid diversion and dissipation, the opening area of ​​the middle layer air inlet 111b is larger than the opening area of ​​the bottom layer air inlet 111c, and the opening area of ​​the bottom layer air inlet 111c is larger than the opening area of ​​the top layer air inlet 111a.

[0044] In some embodiments, an exhaust channel and an air inlet are provided inside the internal crossbeam 15, and the exhaust channel of the internal crossbeam 15 is connected to the exhaust channel of the side beam 11. The air inlet is not limited to being provided only on the side beam as shown in this disclosure, but can also be provided on the end crossbeam 12.

[0045] Vent holes are provided at the locations where the side beam frame 10 connects to the outside. The gas and fire generated by the thermal runaway of the battery module 2 can be discharged through these vent holes via various venting channels. One or more vent holes can be selectively provided on the side beam frame 10. This disclosure uses the integrated vent holes on the end crossbeam 12 and the protruding side beam 14 as an example for illustration. Figure 2 As shown.

[0046] In some implementations, such as Figure 1 As shown, an exhaust device is preferably installed on the exhaust port. The exhaust device can only be opened under a certain pressure, allowing the high-temperature, high-pressure gas flow in the exhaust channel to be quickly discharged from the exhaust device to the external space of the battery pack. Preferably, the exhaust device uses an explosion-proof valve. Under normal operating conditions, the explosion-proof valve can play a role in preventing dust and water damage and balancing the internal and external pressure of the battery pack.

[0047] In some implementations, such as Figure 2As shown, when multiple exhaust devices are selected, they can be divided into a main exhaust device 5 and a secondary exhaust device 6. The starting pressure threshold of the main exhaust device 5 is lower than that of the secondary exhaust device 6. When a battery module 2 experiences thermal runaway, the generated gas flow enters the corresponding exhaust channel 112 along the air inlets 111 on both sides of the housing cavity of the battery module 2. After passing through the continuous exhaust channels 112 of the side beam frame 10, it reaches the position of the main exhaust device 5. The main exhaust device 5 is activated when it reaches its pressure threshold, forming a smooth channel to discharge the gas flow to the outside of the battery pack, achieving the purpose of rapid pressure relief. If a higher pressure is generated instantaneously inside the battery pack, it will exceed the maximum pressure relief capacity of the main exhaust device 5. When the increased pressure reaches the pressure threshold of the secondary exhaust device 6, the secondary exhaust device 6 is activated to rapidly relieve pressure and ensure that the battery pack does not catch fire or explode. Different installation positions of the main exhaust device 5 and the secondary exhaust device 6 are all within the scope of this disclosure. Preferably, the main exhaust device 5 is installed on the end crossbeam 12, and the secondary exhaust device 6 is installed on the side beam 11 and / or the protruding side beam 13. Preferably, the opening area of ​​the exhaust port corresponding to the main exhaust device 5 is greater than or equal to the opening area of ​​the exhaust port corresponding to the auxiliary exhaust device 6.

[0048] In some implementations, such as Figure 5 As shown, the internal crossbeam 15 is provided with several mounting points 151 and several grooves 152. Preferably, the grooves 152 and mounting points 151 are spaced apart. The mounting points 151 are used to connect with the upper cover 4, which can improve the mode of the battery pack. The grooves 152 and the upper cover 4 form a heat dissipation channel 106 that enables gas exchange between adjacent battery cavities. The lower edge of the grooves 152 is higher than the protective cover 22 of the battery module 2 to prevent ejected material from directly spraying onto the battery module 2 during battery thermal runaway, thus preventing thermal runaway from spreading.

[0049] In some implementations, such as Figure 6 As shown, the internal crossbeam 15 has notches at both ends, forming a passage space with the side beam 11 for connecting the high-voltage busbar. The high-voltage busbar is protected with insulating high-temperature resistant material to prevent insulation failure after battery thermal runaway. In the event of thermal runaway, this passage space forms a commutation and heat dissipation channel 102 that allows gas exchange between adjacent battery cavities. Preferably, as shown... Figure 7 As shown, the internal crossbeam 15 has a central groove, which forms a passage space with the upper cover 4 to accommodate the low-voltage line. The low-voltage line is also protected with high-temperature resistant insulating material to prevent high-temperature insulation failure. This passage space forms a commutation and heat dissipation channel 104 during thermal runaway. Both the commutation and heat dissipation channel 106 formed by the notch and the commutation and heat dissipation channel 104 formed by the central groove simultaneously serve the function of commutation and heat dissipation during battery thermal runaway, dissipating the gas flow inside the battery housing cavity and balancing the internal temperature of the battery pack.

[0050] In some implementations, such as Figure 8 As shown, a liquid cooling plate 17 is provided at the bottom of the battery module 2, and the liquid cooling plate 17 is integrated inside the lower housing 3. In some embodiments, the ends of the liquid cooling plate 17 have several recesses, which, after installation, form through holes with the inner side of the side beam 11, forming a heat exchange channel 101 between the upper and lower spaces of the liquid cooling plate 17 to facilitate gas exchange. In some embodiments, a through hole is formed in the middle of the liquid cooling plate 17, forming a heat exchange channel 103 between the upper and lower spaces of the liquid cooling plate 17 to facilitate gas exchange. Preferably, the through hole of the liquid cooling plate 17 is located at the centerline of the liquid cooling plate 17. Preferably, the through hole of the liquid cooling plate 17 is oblong. The bottom of the liquid cooling plate 17 is provided with a bottom protective plate 16, and a heat exchange channel 105 is formed between the bottom protective plate 16 and the liquid cooling plate 17. The heat exchange channel 105 is connected to the heat exchange channels 101 and 103, and is also connected to the exhaust channel of the side beam 11, so that the exhaust channel 112 of the opposite side beam 11 is connected through the heat exchange channel 105.

[0051] Figure 10 The commutation path within the battery pack is shown. When a single cell 211 within the battery module 2 experiences thermal runaway, a violent chemical reaction occurs inside the cell 211, instantly generating a large amount of heat, accompanied by a pressurized ejection of gas and sparks. The explosion-proof vent serves to guide and disperse the heat, allowing it to dissipate rapidly and preventing the ejected material from accumulating inside the battery module 2. The ejected gas and sparks are dispersed at the top of the battery module 2 through commutation and heat dissipation channels 102, 104, and 106, performing X-directional commutation and heat dissipation. The commutation path is as follows: Figure 8 As shown in Figures a1 to a5; simultaneously, heat dissipation is achieved along the Z-direction on both sides and in the middle of the battery module 2 through commutation heat dissipation channels 101 and 103, with the commutation path as follows. Figure 10 As shown in the diagram, b1 to b3; simultaneously, heat dissipation is achieved at the bottom of the battery module 2 along the Y direction through the commutation heat dissipation channel 105, and the commutation path is as follows. Figure 10 As shown in c1 to c2, the gas flow enters the exhaust channel inside the side beam frame 10 after being dispersed in multiple directions, and then exits the battery pack lower box body through the exhaust hole.

[0052] Through the commutation heat dissipation design, the high-temperature gas flow generated after thermal runaway of a certain cell 211 in the battery pack is dispersed to multiple battery housing cavities, and then directional explosion is achieved through the exhaust holes on the side beam frame 10. The commutation heat dissipation design can not only balance the temperature inside the battery pack, but also reduce the damage to the housing caused by excessive local temperature in a certain battery housing cavity, and prevent the spread of thermal runaway caused by excessive local temperature in a certain battery housing cavity.

[0053] A battery pack according to a second aspect of this disclosure includes: the lower battery housing 1 in the above embodiment.

[0054] A vehicle according to a third aspect of this disclosure includes: the battery pack described in the above embodiments.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] Although embodiments of this disclosure have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery pack lower housing, comprising a lower housing body (100), characterized in that, The lower housing body (100) includes a side beam frame (10), a bottom protective plate (16), and an internal crossbeam (15). The internal crossbeam (15) divides the lower housing body (100) into multiple battery receiving cavities for accommodating battery modules (2). The side beam frame (10) has an air inlet (111), an exhaust channel (112), and an exhaust hole. The air inlet (111) is connected to the exhaust hole through the exhaust channel (112). The air inlet (111) is used to introduce the gas flow generated during thermal runaway of the battery module (2) into the exhaust channel (112). The exhaust hole is used to discharge the gas flow that flows to the exhaust hole through the exhaust channel (112) from the lower housing body. The body (100) has an internal crossbeam (15) with a groove and a notch at the end, the groove and the notch connecting adjacent battery cavities; the bottom of the battery module (2) has a liquid cooling plate (17), the liquid cooling plate (17) is integrated inside the lower housing body (100), the heat exchange channel (105) formed between the liquid cooling plate (17) and the bottom protective plate (16) is connected to the exhaust channel, the end of the liquid cooling plate (17) has several recesses, forming a heat exchange channel (101) between the upper space of the liquid cooling plate (17) and the lower space of the liquid cooling plate (17) that can realize gas exchange, the two heat exchange channels (101, 105) are connected.

2. The lower housing of the battery pack according to claim 1, characterized in that, The notch is located at the upper part of the end of the inner beam (15).

3. The lower housing of the battery pack according to claim 1, characterized in that, The internal crossbeam (15) is provided with a plurality of mounting points (151), which are used to connect with the top cover (4) of the battery pack. The groove (152) is spaced apart from the mounting points (151).

4. The lower housing of the battery pack according to claim 3, characterized in that, The battery module (2) within the battery housing cavity includes a protective cover (22), and the lower edge of the groove (152) is higher than the height of the protective cover (22) of the battery module (2).

5. The lower housing of the battery pack according to claim 3, characterized in that, The opening area of ​​several of the grooves (152) gradually decreases from both ends of the inner crossbeam (15) toward the middle.

6. The lower housing of the battery pack according to claim 1, characterized in that, The liquid cooling plate (17) has a through hole in the middle surface, forming a gas exchange heat dissipation channel (103) between the upper space of the liquid cooling plate (17) and the lower space of the liquid cooling plate (17).

7. The lower housing of the battery pack according to claim 6, characterized in that, The through hole of the liquid cooling plate (17) is located at the center line of the liquid cooling plate (17).

8. The lower housing of the battery pack according to claim 7, characterized in that, The through holes of the liquid cooling plate (17) are oblong.

9. A battery pack, characterized in that, It includes the lower housing (1) of the battery pack according to any one of claims 1-8 and the battery module (2) disposed in the receiving cavity.

10. A vehicle, characterized in that, Includes the battery pack as described in claim 9.

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