Battery pack and working machine

Abstract

The present disclosure relates to a battery pack and a construction machine. The battery pack comprises an outer box body, a battery module and an upper cover assembly. The outer box body comprises a bottom wall and a side wall arranged along the circumferential edge of the bottom wall, and the bottom wall and the side wall enclose a containing cavity. The battery module is arranged in the containing cavity. The upper cover assembly is used to cover the opening of the containing cavity. The upper cover assembly comprises a first cover body and a second cover body. The first cover body covers the upper side of the battery module, and the second cover body covers the upper side of the first cover body. The heat insulation performance of the first cover body is better than that of the second cover body. Through the double sealing scheme, the risk of high temperature and high pressure gas released by the battery module due to thermal runaway leaking outward can be reduced, and the risk of water vapor and dust outside the battery pack invading the battery pack can also be reduced, thereby improving the reliability of the battery pack in complex environments. The first cover body has relatively better heat insulation performance, which can block the high temperature and high pressure gas released by the battery module when the battery module is in thermal runaway, and hinder the outward transmission of high temperature.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery pack and engineering machinery. Background Technology

[0002] With the continuous upgrading and breakthroughs in new energy technologies, the electrification of construction machinery has become an important trend in the industry. As a core component of electrified construction machinery, the performance and reliability of batteries directly affect the overall efficiency and operational safety of the machinery.

[0003] Therefore, improving the safety of battery use is an urgent problem to be solved. Summary of the Invention

[0004] This application provides a battery pack and engineering machinery to improve safety in use.

[0005] The first aspect of this application provides a battery pack, comprising: The outer casing includes a bottom wall and side walls provided along the circumferential edge of the bottom wall, the bottom wall and the side walls enclosing a receiving cavity; The battery module is housed within the receiving cavity; and The top cover assembly is used to cover the opening of the receiving cavity. The top cover assembly includes a first cover and a second cover. The first cover is placed on the upper side of the battery module, and the second cover is placed on the upper side of the first cover. The heat insulation performance of the first cover is better than that of the second cover.

[0006] In some embodiments, the portion of the top of the sidewall furthest from the receiving cavity protrudes relative to the portion near the receiving cavity to form a groove structure on the top of the sidewall, a first cover rests on the groove structure, and a second cover rests on the protruding portion of the top of the sidewall.

[0007] In some embodiments, the battery pack further includes a first seal disposed between the first cover and the recessed structure.

[0008] In some embodiments, the battery pack further includes at least two pressure relief structures disposed on the sidewalls, the pressure relief structures being used to release pressure within the containment cavity in the event of thermal runaway of the battery module.

[0009] In some embodiments, at least two pressure relief structures include at least two explosion-proof valves, which are spaced apart on the sidewalls.

[0010] In some embodiments, the outer casing has a rectangular outline, and at least two explosion-proof valves are respectively disposed on two opposite side walls of the outer casing.

[0011] In some embodiments, the sidewall has a through hole, and at least two pressure relief structures further include a pressure relief plate that seals the through hole. The melting point of the pressure relief plate is lower than that of the sidewall. When the battery module experiences thermal runaway and the temperature inside the cavity rises above the melting point of the pressure relief plate, the pressure relief plate melts.

[0012] In some embodiments, the pressure relief plate is connected to the sidewall by fasteners.

[0013] In some embodiments, the first cover is made of a composite material and the second cover is made of a metallic material.

[0014] In some embodiments, the battery pack further includes a connector disposed on the side wall for connecting an external fire extinguishing system to inject fire extinguishing agent into the containment cavity.

[0015] A second aspect of this application provides an engineering machine including a battery pack as described above, the battery pack being used to power the engineering machine.

[0016] According to the technical solution provided in this application, the double-sealing design reduces the risk of high-temperature, high-pressure gas leakage from the battery module due to thermal runaway, and also reduces the risk of moisture and dust from outside the battery pack entering the battery pack. Even if the first cover is partially burned under extreme conditions, the outer second cover can still block the high-temperature, high-pressure gas inside the pack, preventing it from directly escaping and improving the reliability of the battery pack in complex environments. Furthermore, the first cover has relatively better thermal insulation performance, allowing it to block the release of high-temperature, high-pressure gas from the battery module when thermal runaway occurs, preventing heat transfer and improving the safety of the battery pack. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this application, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation thereof. In the drawings: Figure 1 This is an exploded view of a battery pack according to some embodiments of this application.

[0018] Figure 2 This is a schematic diagram of the outer casing structure in some embodiments of this application.

[0019] Figure 3 for Figure 1 A schematic diagram of the overall structure of the battery pack after assembly.

[0020] Explanation of reference numerals in the attached figures

[0021] 1. Side wall; 11. Pressure relief plate; 12. Explosion-proof valve; 13. Connector; 2. Battery module; 3. First cover; 4. Second cover; X, length direction; Y, width direction; Z, height direction. Detailed Implementation

[0022] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0023] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0024] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0025] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0026] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0027] New energy construction machinery is experiencing rapid development. Compared to passenger vehicles, the battery packs used in construction machinery operate in harsher environments (rapid temperature changes, high dust levels, etc.) and have a wider range of power requirements. Based on these requirements, construction machinery places stricter demands on its battery packs: Construction machinery operates in harsh environments for extended periods, requiring battery packs to possess high strength and adequate sealing performance to prevent external dust and moisture from entering and causing hazards; the wide energy range and high energy demand of battery packs used in construction machinery far exceed those of passenger vehicles, making them more dangerous in the event of thermal runaway, necessitating more robust explosion-proof measures.

[0028] Therefore, refer to Figures 1-3 This application provides a battery pack in some embodiments, including an outer casing, a battery module 2, and a top cover assembly. The outer casing includes a bottom wall and side walls 1 disposed along the circumferential edge of the bottom wall, the bottom wall and side walls 1 enclosing a receiving cavity. The battery module 2 is disposed in the receiving cavity. The top cover assembly is used to cover the open portion of the receiving cavity. The top cover assembly includes a first cover 3 and a second cover 4. The first cover 3 covers the upper side of the battery module 2. The second cover 4 covers the upper side of the first cover 3. The heat insulation performance of the first cover 3 is better than that of the second cover 4.

[0029] Specifically, battery module 2 includes multiple integrated battery cells, each being the smallest unit of a battery. Each battery cell includes a housing, an electrode assembly housed within the housing, and an electrolyte. The electrode assembly is formed by winding or stacking positive and negative electrode plates. A pressure relief structure is provided on the housing to release pressure in the event of thermal runaway in a battery cell.

[0030] The bottom wall of the outer casing has a rectangular outline, and side walls 1 are arranged around the circumferential edge of the bottom wall to form a rectangular receiving cavity. The battery module 2 is placed in the receiving cavity. The bottom wall supports the bottom of the battery module 2, and the side walls 1 limit the circumferential movement of the battery module 2, thereby stably placing the battery module 2 in the receiving cavity. Correspondingly, the first cover 3 and the second cover 4 are both configured as plates with rectangular outlines, and the dimensions of the first cover 3 and the second cover 4 are adapted to the dimensions of the receiving cavity. The first cover 3 is located at the open part of the receiving cavity and is positioned above the battery module 2. Thus, the first cover 3 closes the receiving cavity, providing a first layer of sealing. The second cover 4 is positioned above the first cover 3, further sealing the receiving cavity on top of the first layer of sealing.

[0031] The double-sealing design reduces the risk of high-temperature, high-pressure gas leakage from battery module 2 due to thermal runaway, and also reduces the risk of moisture and dust from outside the battery pack entering the pack. Even if the first cover 3 is partially burned under extreme conditions, the outer second cover 4 can still block the high-temperature, high-pressure gas inside the pack, preventing it from directly escaping and improving the reliability of the battery pack in complex environments. Furthermore, the first cover 3 has relatively better thermal insulation performance, allowing it to block the high-temperature, high-pressure gas released from battery module 2 in the event of thermal runaway, preventing heat transfer and enhancing the safety of the battery pack.

[0032] In some embodiments, the second cover 4 is configured to have better rigidity than the first cover 3, thereby improving the overall structural strength of the battery pack.

[0033] In some embodiments, the battery module 2 includes multiple sub-modules stacked in the height direction Z. Each sub-module includes multiple battery cells arranged side by side. A cold plate is provided on the bottom wall of the outer casing, the bottommost sub-module is placed on the cold plate, and the remaining sub-modules are placed above the bottommost sub-module. This multi-layer stacking scheme allows for flexible configuration of the total battery pack capacity. For example, by increasing the height of the sidewalls to accommodate more sub-modules, the range between the minimum and maximum capacity can reach 100 kWh.

[0034] In some embodiments, the first cover 3 is made of a composite material, and the second cover 4 is made of a metallic material.

[0035] When thermal runaway occurs inside the battery pack, the high-temperature, high-pressure gas first comes into contact with the first cover 3 (composite material). The ablation resistance and low thermal conductivity of the composite material can delay heat transfer to the second cover 4, preventing the outer metal from rapidly heating up, melting, or deforming. The second cover 4 (metal) can be manufactured using sheet metal stamping technology to obtain high-precision sealing surfaces and mounting holes, facilitating connection with the outer casing, ensuring reliable sealing, and also providing superior rigidity for the entire upper cover assembly.

[0036] In some embodiments, the portion of the top of the sidewall 1 furthest from the receiving cavity protrudes relative to the portion near the receiving cavity to form a groove structure on the top of the sidewall 1. A first cover 3 rests on the groove structure. A second cover 4 rests on the protruding portion at the top of the sidewall 1.

[0037] With the help of the protruding structure at the top of the side wall 1, there is a certain height difference between the inner and outer sides of the side wall 1, thus forming a groove structure at the top of the side wall 1. The end face of the non-protruding part of the top of the side wall 1 forms the bottom surface of the groove structure, and the protruding part of the top of the side wall 1 forms the side surface of the groove structure. The first cover 3 is placed on the bottom surface of the groove, and the side surface of the groove, or the protruding part, limits the circumferential edge of the first cover 3. The top end face of the protruding part of the top of the side wall 1 is provided with a mounting hole, and the second cover 4 is placed on the top end face of the protruding part and is fixedly connected to the top end face of the outer side through the mounting hole.

[0038] In this embodiment, the groove structure allows the edge of the first cover 3 to be embedded inside the top of the side wall 1, rather than being entirely stacked on top of the side wall 1. In other words, the second cover 4 covers the entire surface of the first cover 3. This method reduces the overall space occupied by the top cover assembly in the height direction Z of the battery pack, which helps to arrange more battery modules 2 within a limited height space and improves the overall energy density of the battery pack. After the first cover 3 is embedded in the groove structure, multiple sealing interfaces can be formed between it and the top of the side wall 1, such as the bottom and side surfaces of the groove. Compared with the method of directly laying the first cover 3 flat on the top surface of the side wall 1, the groove structure increases the length and tortuosity of the sealing interfaces, further improving the sealing performance of the battery pack.

[0039] In some embodiments, the battery pack further includes a first sealing element disposed between the first cover 3 and the groove structure. Specifically, the first sealing element has a certain elasticity and is disposed on the circumferential edge of the first cover 3. When the first cover 3 is placed on the groove structure, the first sealing element is deformed by the first cover 3 and the side of the groove to provide a sealing effect, thereby further improving the sealing performance of the battery pack.

[0040] In some embodiments, the battery pack further includes a second seal disposed between the first cover 3 and the second cover 4.

[0041] In some embodiments, the first seal and the second seal are foam.

[0042] In some embodiments, the battery pack further includes at least two pressure relief structures disposed on the sidewall 1. The pressure relief structures are used to release pressure within the containment cavity in the event of thermal runaway of the battery module 2.

[0043] In the event of thermal runaway in battery module 2, the pressure inside the containment cavity will increase. At this time, the pressure relief structure can release the pressure in a timely manner, improving safety. Furthermore, setting two pressure relief structures can enhance the pressure relief capability of the battery pack during thermal runaway.

[0044] In some embodiments, at least two pressure relief structures include at least two explosion-proof valves 12, which are spaced apart on the sidewall 1.

[0045] By installing at least two explosion-proof valves 12 on the side wall 1, even if one of the explosion-proof valves 12 fails due to a malfunction (e.g., it cannot open properly or vents poorly), the remaining explosion-proof valves 12 can still release pressure. This redundancy design ensures the safety of the battery pack. Positioning the explosion-proof valves 12 at different locations on the side wall 1 prevents concentrated gas ejection from a single area, thus avoiding the formation of localized powerful jets. Furthermore, the simultaneous opening of both explosion-proof valves enhances the battery pack's ability to release high-temperature, high-pressure gases. (Reference) Figure 2 In some embodiments, the outer casing has a rectangular outline, and at least two explosion-proof valves 12 are respectively disposed on two opposite side walls of the outer casing.

[0046] Specifically, the side wall 1 includes two first side walls and two second side walls arranged opposite to each other. The first side walls and the second side walls are perpendicular to each other. At least two explosion-proof valves 12 are arranged opposite to each other on the two first side walls or the two second side walls. With this scheme, when thermal runaway occurs and the at least two explosion-proof valves 12 are opened, high-temperature and high-pressure gases can be discharged from the explosion-proof valves 12 on both sides respectively. Compared with the scheme of setting two explosion-proof valves 12 on adjacent side walls (i.e., one is set on the first side wall and the other is set on the second side wall), the exhaust efficiency can be improved.

[0047] In some embodiments, the sidewall 1 has a through hole. At least two pressure relief structures also include a pressure relief plate 11. The pressure relief plate seals the through hole. The melting point of the pressure relief plate 11 is lower than that of the sidewall 1. When the battery module 2 experiences thermal runaway and the temperature inside the housing rises above the melting point of the pressure relief plate 11, the pressure relief plate 11 melts.

[0048] Specifically, the pressure relief plate 11 is made of plastic, for example, and the side wall 1 is made of aluminum. In the event of severe thermal runaway, the temperature and pressure inside the containment cavity will rise sharply in a short period of time. The explosion-proof valve 12 cannot reduce the internal pressure in time. Especially in some extreme cases, the temperature inside the containment cavity will exceed 300°C. This temperature exceeds the melting point of plastic but is lower than the melting point of aluminum. At this time, the pressure relief plate 11 will melt, causing the through hole to be opened. The high-temperature and high-pressure gas inside the containment cavity can be discharged through the through hole, which improves the safety and reliability of the battery pack under extreme conditions.

[0049] In some embodiments, the pressure relief plate 11 is connected to the side wall 1 by fasteners.

[0050] Specifically, the pressure relief plate 11 has a threaded hole. The size of the pressure relief plate 11 is slightly larger than the size of the through hole. The pressure relief plate 11 is placed over the through hole, and the pressure relief plate 11 is connected to the side wall 1 using a threaded connector. (Refer to...) Figure 2 In some embodiments, the battery pack also includes a connector 13 disposed on the side wall 1. The connector 13 is used to connect an external fire extinguishing system to inject fire extinguishing agent into the containment cavity.

[0051] In the event of thermal runaway, especially during a fire, in addition to protection through the aforementioned pressure relief structure, fire extinguishing agents can be injected into the battery pack through connector 13 to extinguish the fire, such as perfluoroacetone.

[0052] In some embodiments, the side wall of the battery pack is provided with a plurality of spaced connectors 13. By providing a plurality of connectors 13, multiple connectors 13 can be connected to the fire extinguishing system at the same time when a fire starts, thereby increasing the amount of fire extinguishing agent injected and improving the fire extinguishing effect.

[0053] Some embodiments of this application also provide an engineering machine, including a battery pack as described above, the battery pack being used to power the engineering machine.

[0054] The engineering machinery provided in this embodiment has a battery pack with superior safety, thus ensuring the reliability of the engineering machinery in complex scenarios.

[0055] The structure of a battery pack according to a specific embodiment of this application is described below.

[0056] refer to Figures 1-3 The battery pack includes an outer casing, a battery module 2, a first cover 3 (made of PCM composite material) and a second cover 4 (made of aluminum profile).

[0057] The outer casing is entirely constructed from extruded aluminum profiles, welded together to achieve a sealed enclosure. The outer casing includes a bottom wall and side walls 1 along the circumferential edge of the bottom wall. The bottom wall has an approximately rectangular outline, and the side walls 1 are arranged around their edges to form a rectangular receiving cavity. A cold plate is integrated into the bottom wall. The battery module 2 includes a first sub-module and a second sub-module. The first sub-module is directly mounted on the cold plate, and the second sub-module is positioned above the first sub-module. The side walls 1, near the bottom wall in the height direction, have a limiting structure to position the first sub-module. Specifically, the battery cells in the first sub-module are positioned by the inner wall of the receiving cavity (specifically, the limiting structure on the side wall 1). The second sub-module has an independent frame structure, which defines multiple independent installation spaces for pre-fixing multiple battery cells. After assembly, the frame structure with the battery cells is placed inside the receiving cavity, and the side walls 1 further limit its overall positioning.

[0058] The portion of the top of sidewall 1 furthest from the receiving cavity protrudes relative to the portion closest to the receiving cavity, forming a groove structure on the top of sidewall 1. A first cover 3 is mounted on the groove structure. A second cover 4 is mounted on the protruding portion of the top of sidewall 1. The end face of the non-protruding portion of the top of sidewall 1 forms the bottom surface of the groove structure, and the protruding portion of the top of sidewall 1 forms the side surface of the groove structure. The first cover 3 is mounted on the bottom surface of the groove. The top end face of the protruding portion of the top of sidewall 1 has multiple mounting holes. The second cover 4 is mounted on the top end face of the protruding portion and is fixedly connected to the top end face of the outer side surface through these mounting holes.

[0059] Sidewall 1 includes two first sidewalls and two second sidewalls arranged opposite each other. The first and second sidewalls are perpendicular, and the length of the first sidewall is longer than that of the second sidewall. The first sidewall forms the long side of the rectangular receiving cavity, and its extension direction is the length direction X of the battery pack. The second sidewall forms the short side of the receiving cavity, and its extension direction is the width direction Y of the battery pack. Two explosion-proof valves 12 are respectively provided on the two second sidewalls. A through hole and a pressure relief plate 11 are also provided on one of the second sidewalls. The through hole extends through the thickness direction of the second sidewall. The pressure relief plate 11 is fixedly connected to the second sidewall by a threaded connector, thereby covering and sealing the through hole. The pressure relief plate 11 is made of rigid plastic material, and its melting point is lower than that of sidewall 1. When thermal runaway causes the temperature to rise sharply to exceed the melting point of the pressure relief plate 11, the pressure relief plate 11 melts to open the through hole. Two connectors 13 are also provided on the second side wall where the pressure relief plate 11 is not provided. The two connectors 13 are spaced apart in the height direction Z and the width direction Y. Both connectors 13 can be connected to an external fire extinguishing system to inject fire extinguishing agent (such as perfluoroacetone) into the battery pack when a fire occurs inside the battery pack.

[0060] In this embodiment, safety redundancy is implemented for both the sealing and pressure relief of the battery pack, which improves the reliability of the battery pack in complex environments. Based on the embodiments of this disclosure described above, unless explicitly denied or conflicted, the technical features of one embodiment can be advantageously combined with one or more other embodiments.

[0061] This document uses specific embodiments to illustrate the principles and implementation methods of this disclosure. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this disclosure. It should be noted that those skilled in the art can make various improvements and modifications to this disclosure without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this disclosure.

Claims

1. A battery pack, characterized in that, include: The outer casing includes a bottom wall and a side wall (1) disposed along the circumferential edge of the bottom wall, the bottom wall and the side wall (1) enclosing a receiving cavity; The battery module (2) is disposed in the receiving cavity; and The top cover assembly is used to cover the opening of the receiving cavity. The top cover assembly includes a first cover (3) and a second cover (4). The first cover (3) covers the upper side of the battery module (2), and the second cover (4) covers the upper side of the first cover (3). The heat insulation performance of the first cover (3) is better than that of the second cover (4).

2. The battery pack according to claim 1, characterized in that, The portion of the top of the sidewall (1) away from the receiving cavity protrudes relative to the portion near the receiving cavity to form a groove structure on the top of the sidewall, the first cover (3) rests on the groove structure, and the second cover (4) rests on the protruding portion at the top of the sidewall (1).

3. The battery pack according to claim 2, characterized in that, The battery pack also includes a first seal disposed between the first cover (3) and the groove structure.

4. The battery pack according to claim 1, characterized in that, The battery pack also includes at least two pressure relief structures disposed on the side wall (1), which are used to release the pressure in the containment cavity in the event of thermal runaway of the battery module.

5. The battery pack according to claim 4, characterized in that, The at least two pressure relief structures include at least two explosion-proof valves (12), which are spaced apart on the side wall (1).

6. The battery pack according to claim 5, characterized in that, The outer casing has a rectangular outline, and the at least two explosion-proof valves (12) are respectively disposed on two opposite side walls of the outer casing.

7. The battery pack according to claim 4, characterized in that, The sidewall (1) has a through hole, and the at least two pressure relief structures further include a pressure relief plate (11). The pressure relief plate seals the through hole. The melting point of the pressure relief plate (11) is lower than that of the sidewall (1). When the battery module (2) experiences thermal runaway and the temperature inside the cavity rises to a level exceeding the melting point of the pressure relief plate (11), the pressure relief plate (11) melts.

8. The battery pack according to claim 7, characterized in that, The pressure relief plate (11) is connected to the side wall (1) by fasteners.

9. The battery pack according to any one of claims 1 to 8, characterized in that, The first cover (3) is made of composite material, and the second cover (4) is made of metal material.

10. The battery pack according to any one of claims 1 to 8, characterized in that, The battery pack also includes a connector (13) disposed on the side wall (1), the connector (13) being used to connect an external fire extinguishing system to inject fire extinguishing agent into the containment cavity.

11. An engineering machinery, characterized in that, Includes the battery pack as described in any one of claims 1 to 10, the battery pack being used to power the construction machinery.

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