Electric tool, outdoor wheeled tool and battery pack

Abstract

The invention discloses an electric tool, an outdoor wheeled tool and a battery pack. The battery pack comprises a shell; the battery cell module comprises a plurality of battery cell units, and the battery cell module is arranged in the shell; the pressure relief device is arranged on the shell; and the pressure relief device is arranged to at least guide high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the shell.

Description

Technical Field

[0001] The present application relates to energy storage, and in particular to an electric tool, an outdoor wheeled tool and a battery pack. Background Art

[0002] At present, the application of lithium batteries is becoming more and more extensive. At the same time, the safety of its application products has also received more and more attention. However, thermal runaway events caused by cell failure are emerging in an endless stream, causing serious harm and impact on people's production and life.

[0003] This section provides background information related to the present application which is not necessarily prior art. Summary of the invention

[0004] In order to address the deficiencies of the prior art, the purpose of the present application is to provide a battery pack with higher safety performance and an electric tool using the battery pack.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions: A battery pack comprises: a shell; a battery cell module comprising a plurality of battery cell units, wherein the battery cell module is arranged in the shell; and a pressure relief device installed in the shell; wherein the pressure relief device is arranged to at least guide the high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the shell.

[0006] In some embodiments, the pressure relief device includes: a guide assembly, which forms a guide channel for guiding the flow of the high-temperature gas.

[0007] In some embodiments, the guide channel includes at least a plurality of cyclonic airflow flow paths.

[0008] In some embodiments, the guide assembly includes: a first guide member disposed toward the inner side of the battery pack, and a second guide member disposed opposite to the first guide member; a channel entrance of the guide channel is disposed on the first guide member.

[0009] In some embodiments, the first guide member is detachably connected to the second guide member.

[0010] In some embodiments, the guide assembly includes: a first guide rib is provided on the end surface of the first guide member opposite to the second guide member; and a second guide rib is provided on the end surface of the second guide member opposite to the first guide member.

[0011] In some embodiments, the first guide rib and the second guide rib are configured to define and form the guide channel.

[0012] In some embodiments, a first distance from a lower vertex of the first guide rib to an upper surface of the second guide member is greater than zero; and a second distance from an upper vertex of the second guide rib to a lower surface of the first guide member is greater than zero.

[0013] In some embodiments, the first distance is equal to the second distance.

[0014] In some embodiments, the first distance is not equal to the second distance.

[0015] In some embodiments, the guide assembly is made of a metal material.

[0016] In some embodiments, the pressure relief device further includes: a sealing member disposed at an upper end of the first guide member to seal a gap between the guide assembly and the housing.

[0017] In some embodiments, the pressure relief device further includes: a fire-blocking assembly disposed inside the guide assembly, configured to at least prevent an open flame generated by thermal runaway of the battery cell unit from entering the guide assembly.

[0018] In some embodiments, the fire-blocking assembly includes at least: a partition net having a plurality of fire-blocking holes.

[0019] In some embodiments, the partition net is disposed at the innermost side of the pressure relief device.

[0020] In some embodiments, the spacer comprises at least two layers of adjacently arranged metal meshes.

[0021] In some embodiments, the spacer includes at least two adjacent layers of metal foam.

[0022] In some embodiments, at least one metal mesh layer has a phase change coating on its outer side.

[0023] In some embodiments, fire extinguishing material is disposed at least between adjacent metal meshes.

[0024] In some embodiments, a fire extinguishing material is disposed at least between adjacent metal foams.

[0025] In some embodiments, the pressure relief device further includes: a diaphragm disposed between the guide assembly and the fire-blocking assembly.

[0026] A battery pack comprises: a shell; a battery cell module comprising a plurality of battery cell units, wherein the battery cell module is arranged in the shell; and a pressure relief device installed to the shell; wherein the pressure relief device comprises at least: a fire-blocking assembly, which is arranged to at least prevent an open flame generated by thermal runaway of at least one battery cell unit from escaping from the shell.

[0027] In some embodiments, the pressure relief device further includes: a guide assembly configured to at least guide the high-temperature gas coming out of the fire-blocking assembly to the outside of the shell.

[0028] In some embodiments, the fire-blocking assembly includes at least: a partition net having a plurality of fire-blocking holes.

[0029] In some embodiments, the partition net is disposed at the innermost side of the pressure relief device.

[0030] In some embodiments, the spacer comprises at least two layers of adjacently arranged metal meshes.

[0031] In some embodiments, at least one metal mesh layer has a phase change coating on its outer side.

[0032] In some embodiments, fire extinguishing material is disposed at least between adjacent metal meshes.

[0033] In some embodiments, the pressure relief device further includes: a diaphragm disposed between the guide assembly and the fire-blocking assembly.

[0034] A battery pack comprises: a shell; a battery cell module comprising a plurality of battery cell units, wherein the battery cell module is arranged in the shell; a pressure relief device is arranged in the shell; wherein the pressure relief device comprises at least: a fire-blocking assembly located at one end of the pressure relief device close to the battery cell module, wherein the fire-blocking assembly is arranged to at least prevent an open flame generated by thermal runaway of at least one battery cell unit from escaping from the shell; and a guide assembly located at the other end of the pressure relief device away from the battery cell module, wherein the guide assembly is arranged to at least guide high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the shell.

[0035] In some embodiments, the pressure relief device further includes: a sealing member disposed at an upper end of the guide assembly to seal a gap between the guide assembly and the shell.

[0036] In some embodiments, the guide assembly forms a guide channel for guiding the flow of the high-temperature gas.

[0037] In some embodiments, a channel entrance of the guide channel is arranged to face the fire-blocking assembly.

[0038] In some embodiments, the guide channel includes a plurality of cyclonic airflow flow paths.

[0039] In some embodiments, the fire-blocking assembly includes at least: a partition net having a plurality of fire-blocking holes.

[0040] In some embodiments, the pressure relief device further includes: a diaphragm disposed between the guide assembly and the fire-blocking assembly.

[0041] An electric tool comprises: a casing; a motor arranged in the casing; a battery mounting portion, arranged to mount a battery pack for at least supplying power to the motor; the battery pack comprises: a shell; a battery module, comprising a plurality of battery units, the battery module being arranged in the shell; a pressure relief device, arranged in the shell; wherein: the pressure relief device is arranged to at least guide high-temperature gas generated by thermal runaway of at least one battery unit to be discharged from the shell; and at least prevent open flames generated by thermal runaway of at least one battery unit from escaping from the shell.

[0042] An outdoor wheeled tool comprises: a frame; running wheels, arranged to support the frame; a motor, configured to at least drive the running wheels to move; a battery compartment, used to accommodate a battery pack, the battery pack at least supplies power to the motor; the battery pack comprises: a shell; a battery module, comprising a plurality of battery units, the battery module being arranged in the shell; a pressure relief device, mounted to the shell; wherein the pressure relief device is arranged to at least guide high-temperature gas generated by thermal runaway of at least one battery unit to be discharged from the shell.

[0043] In some embodiments, the pressure relief device includes: a guide assembly, which forms a guide channel for guiding the flow of the high-temperature gas.

[0044] In some embodiments, the pressure relief device further includes: a fire-blocking assembly disposed inside the guide assembly, configured to at least prevent an open flame generated by thermal runaway of the battery cell unit from entering the guide assembly.

[0045] In some embodiments, the pressure relief device further includes: a diaphragm disposed between the guide assembly and the fire-blocking assembly.

[0046] In some embodiments, the pressure relief device further includes: a sealing member disposed at an upper end of the guide assembly to seal a gap between the guide assembly and the shell.

[0047] In some embodiments, the battery compartment is provided with an exhaust port corresponding to the pressure relief device.

[0048] Beneficial effect: By providing a pressure relief device that can discharge high-temperature gas and prevent open flames from leaking out after thermal runaway occurs in the battery pack, the hazards and impacts caused by thermal runaway of the battery pack are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a stereogram of various outdoor wheeled equipment in one embodiment proposed in the present application; Figure 2a is a perspective view of a riding lawn mower according to an embodiment of the present application; Figure 2bis a perspective view of a riding lawn mower according to another embodiment of the present application; Figure 3 is a three-dimensional diagram of a battery pack according to an embodiment of the present application; Figure 4 yes Figure 3 Partial structural explosion diagram of the battery pack; Figure 5 yes Figure 3 A structural diagram of a pressure relief device for a battery pack; Figure 6 yes Figure 5 Exploded view of the medium pressure relief device; Figure 7 is an exploded view of a pressure relief device in another embodiment; Figure 8 is a perspective view of a battery pack of an embodiment including at least an energy conversion device; Fig. 9 A three-dimensional view of a battery pack of an embodiment including at least an energy conversion device from another perspective Fig.10a and Fig.10b is a structural diagram of a battery pack with compartments in an embodiment; Fig.11 is a schematic diagram of a control circuit in a battery pack in an embodiment; Fig.12 It is a schematic diagram of the battery compartment and battery pack of an outdoor wheeled tool; Fig.13 is a structural diagram of a battery compartment in one embodiment; Fig.14 yes Fig.13 A schematic diagram of the bottom plate of the middle battery compartment; Fig.15 is a structural diagram of a battery pack and a pressure relief device in an embodiment; Fig.16 is a cross-sectional view of a pressure relief device installed on a battery pack housing in one embodiment; Fig.17 is a cross-sectional view of a pressure relief device installed on a battery pack housing in one embodiment; Fig.18 is a structural diagram of a pressure relief device in one embodiment; Fig.19 yes Fig.18 An exploded view of the pressure relief device at one angle; Fig. 20 yes Fig.18 An exploded view of the pressure relief device from another angle; Fig.21 is a cross-sectional view of a pressure relief device in one embodiment; Fig. 22is a cross-sectional view of a pressure relief device in one embodiment; Fig.23 is a partial structural exploded diagram of a battery cell module provided with a pressure relief assembly in one embodiment; Fig.24 is a structural diagram of a battery cell module provided with a pressure relief assembly in an embodiment; Fig.25 The cross-sectional view of a battery cell module provided with a pressure relief assembly in one embodiment. DETAILED DESCRIPTION

[0050] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above drawings.

[0051] In this application, the terms "comprises", "includes", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0052] In this application, the term "and / or" is a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects before and after are in an "and / or" relationship.

[0053] In the present application, the terms "connect", "combine", "couple", and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, direct connection refers to two parts or components being connected together without the need for an intermediate piece, and indirect connection refers to two parts or components being connected to at least one intermediate piece respectively, and the two parts or components being connected via the intermediate piece. In addition, "connect" and "couple" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings.

[0054] In this application, it will be understood by those of ordinary skill in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerances caused by manufacturing, assembly, and use associated with a specific value, etc. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0055] In this application, it will be understood by those skilled in the art that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0056] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, the bottom can include directly below, lower left, lower right, lower front, and lower back, etc.

[0057] In this embodiment, a variety of different types of outdoor wheeled equipment 200 can be powered by the battery pack 100 . Figure 1 Several common wheeled devices are illustrated, such as a riding lawn mower 200a, a snow blower 200b, an all-terrain vehicle 200c, a push lawn mower 200d, and a mobile power supply device 200e, etc. It should be noted that various other common wheeled devices that can be powered by the battery pack 100 are also within the protection scope of the present application, such as a mobile power supply device (English translation: powerstation), a wheeled fan, a wheeled lighting device, a wheeled blower, a cleaning vehicle, etc. In this embodiment, the outdoor wheeled device 200 may also be referred to as an outdoor wheeled tool 200.

[0058] In the following implementation mode, Figure 1The riding lawn mower 200a shown in FIG. Figure 2a The riding lawn mower 200a may include at least a frame 21, a running wheel 22 supporting the frame 21, a motor 23 capable of at least driving the running wheel 22, and a battery compartment 24 for accommodating the battery pack 100. The lawn mower 200a may also include a seat 25 and an operating assembly 26 disposed on the frame 21, wherein the operating assembly 26 may include an operating lever 261, a steering wheel 262, or a pedal 263, etc. The lawn mower 200a may also include a cutting assembly 27 disposed at the lower end of the frame 21, or a lighting device 28 disposed at the front end of the frame 21, etc.

[0059] In some embodiments, the battery compartment 24 may be disposed at the rear end, front end, bottom end, or side of the frame 21 . Figure 2a In the lawn mower 200a shown, the battery compartment 24 is arranged at the front end of the frame 21. Figure 2b In the lawn mower 200a shown, the battery compartment 24 is arranged at the rear end of the frame 21. The positions where the battery compartment 24 is arranged on the lawn mower 200a or other wheeled tools are not listed here one by one.

[0060] In one embodiment, the battery compartment 24 can be integrally formed with the frame 21, that is, the frame 21 can form the battery compartment 24. In one embodiment, the battery compartment 24 can be detachably mounted on the frame 21, that is, the frame 21 can form a battery compartment mounting portion (not shown) to mount the battery compartment 24. In one embodiment, the lawn mower 200a may include a battery compartment 24 integrally formed with the frame 21, and also include a battery compartment 24 detachably mounted on the frame 21. In one embodiment, the battery pack 100 can be detachably mounted in the battery compartment 24, or can be fixedly mounted in the battery compartment 24 or built into the battery compartment 24.

[0061] In one embodiment, the battery compartment 24 is at least partially made of a metal material.

[0062] In this embodiment, the battery compartment 24 can accommodate one or more battery packs 100. In this embodiment, the discharge order or discharge method of the multiple battery packs 100 in the battery compartment 24 to power the lawn mower 200a is not specifically limited. For example, the multiple battery packs 100 can be connected in series to power the lawn mower 200a, or can be discharged in parallel, or can be discharged in sequence, etc. Or a battery pack in the battery compartment 24 can discharge to other battery packs.

[0063] In one embodiment, the battery pack 100 can be removed from the lawn mower 200a to power other power tools, such as handheld tools, such as drills, pruning machines, sanders, etc., and can also power other wheeled power tools, such as snow blowers, and can also power hand-push power tools, such as hand-push lawn mowers and hand-push snow blowers. It can also power bench tools, garden tools, decoration tools, vegetation care tools, or different types of tools such as drills and saws. In other words, the battery pack 100 can at least be a battery pack that is universal for a variety of power tools.

[0064] refer to Figure 3 and Figure 4 The battery pack 100 shown includes at least a housing 11, a cell module 12, and a terminal assembly 13. Among them, the cell module 12 may include a plurality of cell units 121 for storing electrical energy. In this embodiment, the cell unit 121 may be a cylindrical battery, or a square battery, or an aluminum-plastic film battery, or a metal shell battery, or a soft-pack battery, etc. In one embodiment, the cell unit 121 may be a single-pole ear battery, or a bipolar ear battery, or a full-pole ear battery. In this embodiment, at least some of the cell units 121 are lithium iron phosphate cells. Or the positive electrode material of at least some of the cell units 121 is a sodium ion cell. Or the positive electrode material of at least some of the cell units 121 is a capacitor battery. Or the positive electrode material of at least some of the cell units 121 is a lithium ion cell, such as a ternary lithium cell. Or the positive electrode material of at least some of the cell units 121 is a supercapacitor. Or the battery pack 100 is mixed with cells of multiple different materials or properties. The terminal assembly 13 may include a discharge interface that can be connected to an electrical device, or include a charging interface that can be connected to a charging device, or include a charging and discharging interface that can be connected to both an electrical device and a charging device. This embodiment does not limit the type or position of the terminal assembly 13.

[0065] In one embodiment, the nominal voltage of the battery pack 100 is greater than or equal to 30V, or greater than or equal to 20V, or greater than or equal to 10V. Of course, it is understandable that the nominal voltage of the battery pack 200 may be greater than or equal to 20V and less than or equal to 100V, or the nominal voltage of the battery pack 100 may be greater than or equal to 36V and less than or equal to 80V, or the nominal voltage of the battery pack 100 may be greater than or equal to 40V and less than or equal to 60V. Or the nominal voltage of the battery pack 100 may be greater than or equal to 100V and less than or equal to 800V. It is understandable that the nominal voltage of the battery pack 100 may be 20V, 24V, 36V, 40V, 48V, 56V, 60V, 80V, 100V, 400V, 800V. In this way, the voltages of different battery packs of the outdoor wheeled equipment 100 using multiple battery packs 100 can take into account the voltage platforms of other battery packs, thereby increasing the total energy of the battery packs in the wheeled equipment. When at least two battery packs 100 are installed in the outdoor wheeled equipment 200 , the nominal voltages of the at least two battery packs 100 may be the same or different.

[0066] In one embodiment, the weight of the battery pack 200 is greater than or equal to 2 kg. Or the weight of the battery pack 200 is greater than or equal to 5 kg. Or the weight of the battery pack 200 is greater than or equal to 10 kg. Or the weight of the battery pack 200 is greater than or equal to 15 kg. Or the weight of the battery pack 200 is greater than or equal to 16 kg. Or the weight of the battery pack 200 is greater than or equal to 17 kg. Or the weight of the battery pack 200 is greater than or equal to 18 kg. Or the weight of the battery pack 200 is greater than or equal to 19 kg. Or the weight of the battery pack 200 is greater than or equal to 20 kg. The weight energy density of the battery pack is greater than or equal to 100 wh / kg and less than or equal to 200 wh / kg. Or the weight energy density of the battery pack 200 is greater than or equal to 120 wh / kg and less than or equal to 200 wh / kg. Or the weight energy density of the battery pack 200 is greater than or equal to 100 wh / kg and less than or equal to 150 wh / kg. Alternatively, the weight energy density of the battery pack 200 is greater than or equal to 150wh / kg and less than or equal to 200wh / kg. The volume energy density of the battery pack 200 is greater than or equal to 100wh / L and less than or equal to 200wh / L. Alternatively, the volume energy density of the battery pack 200 is greater than or equal to 150wh / L and less than or equal to 200wh / L. Alternatively, the volume energy density of the battery pack 200 is greater than or equal to 90wh / L and less than or equal to 200wh / L. Alternatively, the volume energy density of the battery pack 200 is greater than or equal to 100wh / L and less than or equal to 150wh / L. A higher weight energy density or volume energy density allows the outdoor wheeled device 100 to obtain more energy when installing a battery pack of the same volume or weight, thereby ensuring the endurance of the wheeled device. For example, it can ensure the need for the wheeled device to work outdoors for half a day, while also taking into account the size or load requirements of the device itself.

[0067] The total energy of the battery pack 100 is greater than or equal to 1 kw·h and less than or equal to 8 kw·h. Alternatively, the total energy of the battery pack 100 is greater than or equal to 1 kw·h and less than or equal to 4 kw·h. Alternatively, the total energy of the battery pack 100 is greater than or equal to 500 w·h and less than or equal to 2 kw·h. Alternatively, the total energy of the battery pack 100 is greater than or equal to 2 kw·h and less than or equal to 6 kw·h. Alternatively, the total energy of the battery pack 100 is greater than or equal to 4 kw·h and less than or equal to 8 kw·h. Alternatively, the total energy of the battery pack 100 is greater than or equal to 300 w·h and less than or equal to 8 kw·h. In this way, when at least one battery pack 100 in the outdoor wheeled equipment 200 is in a fully charged state, the outdoor wheeled equipment 200 can mow the lawn for 4 to 6 hours using the battery pack 100.

[0068] It should be noted that there may be a risk of thermal runaway during the use of the battery pack 100 as charging or discharging continues. After thermal runaway occurs, the battery pack 100 may explode or catch fire, which may be a serious safety accident. If the battery pack 100 on the outdoor wheeled tool 200 experiences thermal runaway, it is also a major safety accident for the tool itself. If the battery compartment 24 is designed to be close to the seat 25, it is likely to injure the user.

[0069] In order to reduce the hazards caused by thermal runaway of the battery pack 100, the battery pack 100 may further include a pressure relief device 14, which can discharge the hot air in the battery pack 100 or block the leakage of open flames when thermal runaway occurs, thereby preventing the battery pack 100 from exploding or preventing the battery pack 100 from further damaging the battery compartment 24 or other structures.

[0070] In one embodiment, reference Figures 3 to 5 The pressure relief device 14 can be arranged on the housing 11, and at least includes a waterproof and breathable layer 141 and at least one metal mesh 142. The pressure relief device 14 can be detachably mounted at the mounting opening 11c on the housing 11 by screws or plugging, or fixedly mounted on the housing 11 by other means.

[0071] refer to Figures 5 to 7 , the metal mesh 142 is arranged on the inner side of the waterproof and breathable layer 141. When the air pressure in the shell 11 of the battery pack 100 is basically balanced with the external air pressure, the pressure relief device 14 is basically in a balanced state and does not affect the normal use of the battery pack 100. When the battery pack 100 has thermal runaway, the thermally runaway battery cell 121 may quickly discharge hot air, and the air pressure in the battery pack 100 will increase rapidly, so that the pressure relief device 14 is in a pressure imbalance state. In one embodiment, when the air pressure in the battery pack 100 is greater than the external air pressure, the pressure relief device 14 will be deformed, for example, the pressure relief device 14 will bulge from the inside to the outside, or at least the waterproof and breathable layer 141 will bulge outward. When the air pressure in the battery pack 100 is large enough, it can break through the pressure relief device 14, or at least break through the waterproof and breathable layer 141, so that the hot air in the battery pack 100 is released to the outside of the battery pack 100. It is understandable that the metal mesh 142 is disposed on the inner side of the waterproof and breathable layer 141 . When thermal runaway occurs in the battery pack 100 and an open flame occurs, the metal mesh 142 can block the open flame inside the battery pack 100 to a certain extent.

[0072] In one embodiment, the waterproof breathable layer 141 will rupture when the air pressure inside the battery pack 100 is greater than or equal to 2Kpa, or will rupture when the air pressure inside the battery pack 100 is greater than or equal to 3Kpa, or will rupture when the air pressure inside the battery pack 100 is greater than or equal to 3Kpa, or will rupture when the air pressure inside the battery pack 100 is greater than or equal to 4Kpa.

[0073] In one embodiment, the waterproof and breathable layer 141 is provided with Figure 6 and Figure 7 The pre-indentation 1411 shown, the thickness of the film at the pre-indentation 1411 is less than the thickness at other positions, so it is easier to break. In one embodiment, the shape of the pre-indentation 1411 can be a "*" shape, or a "+" shape or any other shape.

[0074] In one embodiment, the waterproof breathable layer 141 may be a waterproof breathable film, or may be a waterproof breathable valve, or an aluminum-plastic film, etc.

[0075] In one embodiment, the metal mesh 142 may include a first metal mesh 1421 and a second metal mesh 1422 that are adjacently disposed, and the first metal mesh 1421 is disposed inside the second metal mesh 1422. The meshes of the two metal meshes at least partially do not overlap, thereby increasing the mesh density of the metal mesh 142 and enhancing the ability of the metal mesh 142 to block open flames.

[0076] In one embodiment, the pressure relief device 14 is disposed at the bottom housing, side or other position of the battery pack 100. In one embodiment, the battery pack 100 may be provided with a plurality of pressure relief devices 14, which may be disposed on the same surface of the battery pack 100 or on different surfaces.

[0077] In one embodiment, the pressure relief device 14 further includes a protective bracket 143, which is detachably mounted on the sub-shell 11. The waterproof and breathable layer 141 and the metal mesh 142 are detachably mounted to the protective bracket 143, or are non-detachably mounted on the protective bracket 143. In one embodiment, the hardness of the protective bracket 143 is less than or equal to the hardness of the shell 11.

[0078] In one embodiment, the pressure relief device 14 further includes a needle 144. The needle 144 is disposed on the outside of the waterproof breathable layer 141. After the waterproof breathable layer 141 bulges outward to a certain extent, it can contact the needle 144, and the needle 144 can pierce the waterproof breathable layer 141. This further ensures that the waterproof breathable layer 141 can rupture to release the hot air or smoke in the battery pack 100 after thermal runaway of the battery pack 100 occurs. In one embodiment, the needle 144 can be a conical protrusion with the tip facing the waterproof breathable layer 141. In one embodiment, the needle 144 can be formed by a protective bracket 143.

[0079] In some embodiments, when the battery pack 100 is placed on an uneven surface, the protrusions on the ground may pierce the waterproof breathable layer 141 of the pressure relief device 14 from the outside to the inside, thereby damaging the battery pack 100. Or the user may accidentally break the waterproof breathable layer 141 while moving the battery pack 100. In order to prevent the pressure relief device 14 from being triggered before the battery pack 100 has thermal runaway, the battery pack 100 is also provided with a protective structure 145, and the protective structure 145 is disposed on the outside of the waterproof breathable layer 141. In one embodiment, the protective structure 145 is detachably mounted on the outside of the protective bracket 143, or detachably mounted on the shell 11, or integrally formed with the protective bracket 143, or installed on the inside of the protective bracket 143, etc. In one embodiment, the protective structure 145 may be Figure 7 In one implementation, when the battery pack 100 is not installed on the outdoor wheeled tool 200, the protective structure 145 is installed on the battery pack 100. When the battery pack 100 needs to be installed on the outdoor wheeled tool 200 to power the tool, the protective structure 145 can be removed from the battery pack 100 to avoid affecting the triggering of the pressure relief device 14.

[0080] In the above embodiment, the pressure relief device 14 provided on the battery pack shell can serve as a heat dissipation device for the battery pack 100 to dissipate heat for the battery pack when no thermal runaway problem occurs in the battery pack. When thermal runaway occurs in the battery pack, the pressure relief device 14 can quickly discharge the hot air or smoke in the battery pack 100 and prevent open flames from leaking out, thereby avoiding more serious safety accidents.

[0081] refer to Figure 8 and Fig. 9 The battery pack 100 may also include an energy conversion device 15 disposed in the housing 11 and thermally connected to the plurality of battery cells 12. The energy conversion device 15 can at least perform energy conversion from thermal energy to kinetic energy, that is, the energy conversion device 15 can convert the thermal energy in the battery pack 100 into kinetic energy, thereby playing a role in discharging the heat in the battery pack. Figure 8 and Fig. 9 As shown, the energy conversion device 15 can be a fan. In one embodiment, the energy conversion device 15 can be a centrifugal fan. In one embodiment, the fan 15 can be arranged at the corner of the accommodating space formed by the shell 11. If the battery pack 100 has a thermal runaway, the hot air in the battery pack 100 can drive the fan to rotate and be discharged from the circumference of the fan blades of the fan 15 under the action of centrifugal force. In one embodiment, at least one air outlet is provided on the shell 11, and part or all of the air outlet corresponds to the exhaust port of the fan 15. In one embodiment, a guide member 16 is also provided in the shell 11, which can guide the airflow discharged from the fan 15 to be discharged toward the pressure relief port 112 at the shell 11.

[0082] In one embodiment, the radial dimension of the fan 15 is greater than or equal to 50 mm, or greater than or equal to 55 mm, or greater than or equal to 60 mm.

[0083] In the above embodiment, by providing the energy conversion device 15 in the battery pack 100 , the heat energy of the battery pack during thermal runaway can be converted into kinetic energy and discharged.

[0084] refer to Fig.10a and Fig.10b , the battery pack 100 includes at least a first battery cell module 12a and a second battery cell module 12b. The first battery cell module 12a and the second battery cell module 12b are respectively arranged in the first compartment 11a and the second compartment 11b. Among them, the first compartment 11a and the second compartment 11b are thermally isolated. In this embodiment, the shell 11 can form a first compartment 11a and a second compartment 11b. In one embodiment, the first compartment 11a and the second compartment 11b can be two independent inner shells that are thermally isolated from each other and are arranged in the shell 11 and separated from the shell 11. The so-called thermal isolation can be understood as that heat transfer between the two compartments cannot or almost cannot be carried out. In this way, after a battery cell module has thermal runaway, it will not affect another battery cell module or the impact on another battery cell module is small. It can be understood that the first battery cell module 12a and the second battery cell module 12b are connected in parallel. In other words, after one battery cell module fails, the other battery cell module can still support charging and discharging.

[0085] In one embodiment, the thermal conductivity of the body material of the first compartment 11a and the second compartment 11b at room temperature is greater than or equal to 25W / mk, or greater than or equal to 30W / mk, or greater than or equal to 35W / mk, or greater than or equal to 40W / mk. Exemplarily, in one embodiment, the yield strength of the body material of the first compartment 11a and the second compartment 11b is greater than or equal to 150Mpa, or greater than or equal to 160Mpa, or greater than or equal to 170Mpa, or greater than or equal to 180Mpa, or greater than or equal to 190Mpa, etc. In one embodiment, the body material of the first compartment 11a and the second compartment 11b may include at least one of PV6 or flame-retardant nylon.

[0086] For example, Fig. 9As shown, the first compartment 11a may be provided or formed with a first pressure relief port 11a1, and the second compartment 11b may be formed or provided with a second pressure relief port 11b1. A first pressure relief channel 11a2 is formed on the outside of the first compartment 11a, and a second pressure relief channel 11b2 is formed on the outside of the second compartment 11b. The first pressure relief port 11a1 may serve as a port of the first pressure relief channel 11a2, i.e., a first inlet, and the second pressure relief port 11b1 may serve as a port of the second pressure relief channel 11b2, i.e., a second inlet. A pressure relief valve 111 is formed on the housing 11, and the pressure relief valve 111 may serve as an outlet of the first pressure relief channel 11a2 and an outlet of the second pressure relief channel 11b2. In other words, the outlet of the first pressure relief channel 11a2 is the pressure relief valve 111, and the outlet of the second pressure relief channel 11b2 is also the pressure relief valve 111. It is understandable that when a plurality of compartments are provided in the battery pack 100 , the plurality of compartments can also respectively connect their respective pressure relief passages to the pressure relief valve 111 of the shell 11 , thereby achieving the effect of discharging the hot air or smoke in the compartments.

[0087] In this embodiment, the first pressure relief channel 11a2 can be an airflow channel of any shape formed by the first compartment 11a being recessed inward, or can be a hollow airflow channel formed by the compartment body of the first compartment 11a. It can be understood that the second pressure relief channel 11b2 can be formed in the same manner as the first pressure relief channel 11a2, or the shape of the pressure relief channel can be different.

[0088] In one embodiment, in order to increase the time that hot air circulates in the pressure relief channel 11a2, the first pressure relief channel 11a2 and the second pressure relief channel 11b2 may be designed as curved channels, or a buffer structure such as a buffer protrusion or a buffer sheet may be added to the channel.

[0089] In one embodiment, the risk of thermal runaway of the battery pack can also be reduced by electronic components. Fig.11 A circuit structure 1000 in the battery pack 100 shown includes at least one discharge resistor 101, multiple switch elements 102, a parameter detection unit 103 and a controller 104. Each switch element 102 is electrically connected to multiple battery cells 121 and the discharge resistor 101, respectively. The parameter detection unit 103 can at least detect the battery parameters of the battery pack 100. The controller 104 is configured to determine whether the battery pack has a risk of thermal runaway according to the battery parameters, and control at least one switch element 102 to conduct when it is determined that the battery pack 100 has a risk of thermal runaway, so that the battery cell 121 electrically connected thereto can discharge through the discharge resistor 101.

[0090] In this embodiment, the parameter detection unit 103 can at least detect the temperature of the battery cell 121, or the ambient temperature in the battery pack 100, or the air pressure in the battery pack 100. The controller 104 can determine that the battery pack 100 is at risk of thermal runaway when the battery parameter is greater than or equal to the parameter threshold. For example, when the temperature in the battery pack 100 is greater than the temperature threshold, the controller 104 determines that the battery pack 100 is at risk of thermal runaway. After determining that the battery pack 100 is at risk of thermal runaway, the controller 104 can select at least one battery cell 121 to discharge through the discharge resistor 101 according to the power or temperature of the battery cell 121. For example, the battery cell 121 with the highest power can be selected for discharge, or the battery cell 121 with a high temperature can be selected for discharge, or the battery cell 121 to be discharged can be selected after comprehensively considering the temperature and power. In this embodiment, two or more battery cells 121 can be connected in parallel and discharged through the discharge resistor 101.

[0091] The controller 104 can detect the remaining power of the discharged cell unit during the process of the cell unit 121 discharging through the discharge resistor 101, and control the switch element 102 to disconnect when the remaining power is less than or equal to the power threshold, so that the resistor stops discharging. Generally, the power threshold is less than or equal to 50% of the total power of the cell unit.

[0092] In this embodiment, the discharge resistor 101 may be disposed between the housing 11 and the plurality of battery core units 121 , or disposed close to the housing 11 , so as to better transfer heat through the discharge resistor 101 .

[0093] It is understandable that after the battery pack 100 is installed on the outdoor wheeled tool 200, if thermal runaway occurs on the tool, there will be certain safety hazards to the tool itself. Therefore, in order to avoid or minimize the harm of thermal runaway of the battery pack 100 to the outdoor wheeled tool 200, such as Fig.12 As shown, an airflow channel 241 is provided or formed on the battery compartment 24 of the outdoor wheeled tool 200. The housing 11 of the battery pack 100 forms a pressure relief port 112, and the pressure relief port 112 of the battery pack 100 is connected to one end of the airflow channel 241 on the battery compartment 24, while the other end of the airflow channel 241 is connected to the outside atmosphere, so that the hot air or smoke discharged from the battery pack 100 can be discharged to the atmosphere outside the battery compartment 24 through the airflow channel 241 on the battery compartment 24. Among them, the pressure relief port 112 on the battery pack 100 can be the same as or different from the pressure relief valve 111 on the battery pack 100 in the above embodiment, and is not specifically limited here.

[0094] In this embodiment, the battery compartment 24 can accommodate at least one battery pack 200 , and the battery compartment 24 is provided with at least one air flow channel 241 .

[0095] In one embodiment, the airflow channel 241 can also be understood as an opening 2411 on the battery compartment 24 corresponding to the pressure relief port 112 of the battery pack 100 , that is, the channel length of the airflow channel 241 is substantially equal to the compartment wall thickness of the battery compartment 24 .

[0096] In one embodiment, the air flow channel 241 is a channel having a certain general length and an air inlet and an air outlet. Fig.12 As shown, a fireproof cover 242 is further provided outside the battery compartment 24, and the fireproof cover 242 can cover the opening 2411 of the battery compartment 24, and there is a certain distance between the fireproof cover 242 and the outer wall of the battery compartment 24. Thus, an airflow channel 241 can be formed between the fireproof cover 242 and the outer wall of the battery compartment 24, and the opening 2411 of the battery compartment 24 serves as an air inlet of the airflow channel 241. It can be understood that at least one side of the fireproof cover 242 is not connected to the outer wall of the battery compartment 24 to form an air outlet of the airflow channel 241. In this embodiment, the fireproof cover 242 can be fixedly mounted on the battery compartment 24, and can also be detachably mounted to the battery compartment 24.

[0097] In one embodiment, the air flow channel 241 may also be a channel formed by the hollow wall of the battery compartment 24 itself.

[0098] In order to increase the circulation time of hot air in the airflow channel 241, a buffer structure, such as a buffer protrusion or a buffer sheet, etc., may be provided in the airflow channel 241. Alternatively, the airflow channel 241 may be provided as a curved channel.

[0099] In one embodiment, a fireproof structure may be provided in the airflow channel 241 . For example, a metal mesh may be provided as the fireproof structure to prevent an open flame from spreading out of the battery compartment 24 after thermal runaway of the battery pack 100 .

[0100] In one embodiment, the air flow channel 241 formed by the battery compartment 24 can at least guide the hot air after the thermal runaway of the battery pack 100 to the bottom of the battery compartment 24 for discharge. Fig.13 and Fig.14 As shown, a plurality of openings 2431 may be provided on the bottom plate 243 at the bottom of the battery compartment 24, and the openings 2431 may release airflow to the outside atmosphere. In this embodiment, the openings 2431 on the bottom plate 243 may be understood as the airflow channel 241, and the thickness of the bottom plate 243 may be understood as the channel length of the airflow channel 241. By providing a plurality of openings 2431 on the bottom plate 243, the hot air released by the battery pack 100 may be directed to the bottom of the outdoor wheeled tool 200, isolating the heat source from the user on the tool, and avoiding harm to the user on the tool 200.

[0101] In one embodiment, at least the unsealed bottom plate 243 may be recessed outward to form a groove 2432, for example Fig.14 As shown, a rectangular groove 2432 is formed by being recessed outwards at the middle of the bottom plate 243. A plurality of openings 2431 are provided at the groove 2432. In this embodiment, the groove 2432 can gather or converge the hot air in the battery compartment 24 to a certain extent, and lead it to the outside atmosphere through the openings 2431.

[0102] Continue to refer Fig.13 At least one smoke exhaust channel 244 may be formed on the side wall or the top cover of the battery compartment 24 to increase the path for gas or smoke to be exhausted, so that the gas or smoke in the battery compartment 24 can quickly converge to the opening 2431 at the bottom plate 243 and be exhausted out of the battery compartment 24. In one embodiment, the slots on the side wall or the top cover of the battery compartment 24 can serve as the smoke exhaust channel 244.

[0103] In this embodiment, at least one of the compartment walls of the battery compartment 24 is a mesh structure, or at least one of the side walls of the battery compartment 24 is a mesh structure. Exemplarily, the compartment wall of the mesh structure may be a metal mesh, a hard plastic mesh, or a mesh of other materials.

[0104] In this embodiment, the main material of the battery compartment 24 can be an iron-based alloy, or a nickel-based alloy, a cobalt-based alloy, a copper-based alloy, etc.

[0105] In this embodiment, the melting point of the main material of the battery compartment 24 is greater than or equal to 1000° C., or greater than or equal to 1200° C., or greater than or equal to 1400° C., or greater than or equal to 1500° C., etc.

[0106] Continue to refer Fig.13 The battery compartment 24 may include at least two sub-compartments, and a partition 240 is provided between at least two adjacent sub-compartments. The partition 240 is at least partially made of a fire-proof material. In one embodiment, the partition 240 is detachably installed between two adjacent sub-compartments. In one embodiment, the partition 240 is integrally formed with the battery compartment 24. The material of the partition 240 may be consistent with or at least partially consistent with the main material of the battery compartment 24 or different from the main material of the battery compartment 24.

[0107] In one embodiment, the thermal conductivity of the anti-fire material constituting the partition 240 at room temperature is less than or equal to 2 W / m·K, or less than or equal to 1.5 W / m·K, or less than or equal to 1 W / m·K, or less than or equal to 0.5 W / m·K.

[0108] In one embodiment, the battery management module can obtain the battery data of the battery pack 100, and perform a failure convenience model analysis based on the obtained battery data, thereby obtaining various thermal runaway data combinations. In one embodiment, the battery management module can detect the battery data in real time and compare the thermal runaway data combination to determine whether the battery pack has or is about to have thermal runaway, and then control the outdoor wheeled tool to enter a shutdown state, or control the tool to issue an alarm prompt, such as a buzzer alarm or a display screen displaying an alarm message. In this embodiment, the battery management module can be set in the battery pack 100, or in the outdoor wheeled tool 200, or in both.

[0109] In another embodiment, the pressure relief device 14 can at least guide the high-temperature gas generated when at least one battery cell 121 is in thermal runaway to be discharged outside the shell 11. Alternatively, the pressure relief device 14 can at least prevent the open flame generated when at least one battery cell 121 is in thermal runaway from escaping outside the shell 11. Alternatively, the pressure relief device 14 can prevent the open flame generated when at least one battery cell 121 is in thermal runaway from escaping outside the shell 11, and can at least guide the high-temperature gas generated when at least one battery cell 121 is in thermal runaway to be discharged outside the shell 11. It should be noted that the high-temperature gas may include high-temperature smoke or dust or air. In this embodiment, at least the pressure relief device 14 can form a gas connection path between the inside and outside of the shell 11, that is, the inside and outside of the shell 11 can be gas-connected through the pressure relief device 14.

[0110] refer to Fig.15 The pressure relief device 14 can be installed at the installation opening 11c of the housing 11 by means of screws or clamping. Fig.16 The pressure relief device 14 is connected to the housing 11 via a plurality of screws 11d.

[0111] In one implementation, the surface of the housing 11 forming the mounting opening 11c is substantially flush with the outer surface of the pressure relief device 14 after installation, or the surface of the housing 11 forming the mounting opening 11c is higher than the outer surface of the pressure relief device 14 after installation. This avoids the pressure relief device 14 being damaged or triggered by mistake due to the outer surface of the pressure relief device 14 protruding from the surface of the housing 11 during storage or use of the battery pack 100, which causes the pressure relief device 14 to bear the weight of the entire battery pack 100. In other embodiments, the surface of the housing 11 of the mounting opening 11c may also be lower than the outer surface of the pressure relief device 14 after installation.

[0112] In one implementation, the pressure relief device 14 can be installed at the bottom of the battery pack 100, or on the side of the battery pack 100, etc. In principle, the pressure relief device 14 is set at the end of the battery pack 100 away from the user. For example, in a riding lawn mower 200a, the bottom end of the lawn mower 200a faces the ground, which is far away from the operator or users around the body. After the battery pack 100 is installed in the battery compartment 24, the bottom end of the battery pack 100 faces the ground. Therefore, the pressure relief device 14 can be set at the bottom of the battery pack 100, so that when the battery pack 100 in the riding lawn mower 200a has a thermal runaway, the high-temperature gas ejected from the battery pack 100 will face the ground and will not cause damage to people. In other embodiments, the installation position of the pressure relief device 14 on the battery pack 100 is related to the applicable scenario of the battery pack 100 or the type of applicable power tool, which is not limited here.

[0113] In some embodiments, a plurality of pressure relief devices 14 may be installed on the battery pack 100. The positions or quantities of the pressure relief devices 14 installed on battery packs of different types or different uses may be different, which is not limited here.

[0114] This embodiment is described by taking the pressure relief device 14 installed at the bottom of the battery pack 100 as an example. Figures 15 to 20 The direction marked in the figure shall prevail. Figures 16 to 20 As shown, from top to bottom or from near to far from the battery module 12, the pressure relief device 14 may include a fire-blocking component 41 and a guiding component 40. When one or more battery cells 121 in the battery module 12 are in thermal runaway, an open flame or high-temperature gas can be generated in the accommodation space formed by the shell 11 instantly or in a short period of time. Since the pressure relief device 14 has a gas communication path with the outside world, the high-temperature and high-pressure gas generated in the shell 11 will impact the shell 11, and most of it will impact the pressure relief device 14. The fire-blocking component 41 of the pressure relief device 14 can at least prevent the open flame from escaping, and the guiding component 40 can slow down the flow rate of the gas or reduce the temperature of the escaping gas.

[0115] Continue to refer Figures 16 to 20 The fire-blocking assembly 41 may include at least a partition net 411, the guide assembly 40 may include a first guide member 401 and a second guide member 402, a diaphragm 43 is provided between the fire-blocking assembly 41 and the guide assembly 40, and a sealing member 42 is provided between the contact surface of the guide assembly 40 and the shell 11.

[0116] The partition 411 may be a metal mesh and / or metal foam having a plurality of fire-blocking holes 4111. In one embodiment, the partition 411 may be at least two layers of adjacently arranged metal mesh and / or metal foam. The fire-blocking holes 4111 may be mesh holes on the metal mesh or slit holes in the metal foam. On a projection plane perpendicular to the up and down directions, the fire-blocking holes 4111 on the two layers of metal mesh at least partially do not overlap, thereby better blocking open flames. In one implementation, as Figures 18 to 20 As shown, the upper metal mesh can be convex upwards, and the lower metal mesh can be concave downwards, so that a larger space is formed between the two metal meshes to ensure a fire-blocking space between the two layers of metal meshes. Fig.15 The opening shape of the installation opening 11c is a “U” shape, wherein the “opening” inside the “U” shape can be understood as an effective opening, i.e., a through opening on the housing 11, and the opening outside the “U” shape can be used to accommodate the guide assembly 40. In this embodiment, the effective opening of the installation opening 11c can at least expose all the fire-blocking holes 4111 on the partition net 411, so as to maximize the function of the fire-blocking assembly 41.

[0117] In this embodiment, the thickness of a layer of separator 411 or a layer of metal mesh or a layer of metal foam is greater than or equal to 1 mm, for example, greater than or equal to 1.2 mm, or greater than or equal to 1.5 mm, or greater than or equal to 1.8 mm, or greater than or equal to 2 mm, etc.

[0118] In this embodiment, the spacer 411 may also be plastic with ultra-high thermal conductivity, or graphite, or graphene, or CVD diamond film, etc. In some embodiments, the spacer 411 may also have at least a metal coating or a plastic organic coating.

[0119] In this embodiment, the spacer 411 may also be referred to as a metal mesh or a metal spacer or a metal foam. Fig.21 The outer side of at least one layer of metal mesh, or the side facing away from the battery module 12, is provided with a phase change coating 412. When the high-temperature open flame in the housing 11 contacts the inner side of the metal mesh, the phase change coating 412 on the outer side of the metal mesh vaporizes from a solid state into smoke, which can help the metal mesh block the open flame. In one implementation, the phase change coating 412 can be a wax layer. This embodiment does not limit the material of the phase change coating, and other materials that can be vaporized when encountering a high-temperature open flame can also be used as the material of the phase change coating 412.

[0120] In one embodiment, Fig. 22 As shown, a fire extinguishing material 413 may be provided between two adjacent metal meshes. The fire extinguishing material 413 may be a material with high flame retardancy or fire extinguishing property, such as a perfluorohexanone patch or a high-resistance oil, which can assist the metal meshes in blocking open flames.

[0121] It should be noted that the above-mentioned implementation modes can be used alone or in combination, and are not limited here.

[0122] refer to Fig.19 and Fig. 20 The diaphragm 43 disposed at the upper end of the guide assembly 40 and the lower end of the partition 411 can be a waterproof and breathable film, or an aluminum-plastic film, etc., which can isolate impurities such as water vapor and dust under normal conditions. The diaphragm 43 has a certain elasticity, and can bulge from the inside to the outside when the air pressure inside the shell 11 is greater than the air pressure outside the shell 11. Therefore, after the battery pack 100 has thermal runaway, the diaphragm 43 bulges outward, and as the bulge continues to increase, the diaphragm 43 ruptures, so that the gas after passing through the partition 411 can break through the diaphragm 43 and enter the guide assembly 40.

[0123] like Fig.19 As shown, a channel inlet 4031 is provided at the upper end of the guide assembly 40 to allow the gas that escapes through the diaphragm 43 to enter the guide assembly 40. In this embodiment, the first guide 401 is arranged toward the inner side of the battery pack 100, or is arranged close to the fire-blocking assembly 41, or is arranged adjacent to the fire-blocking assembly 41, and the second guide 402 is arranged opposite to the first guide 401. Fig.16 The screw 11d penetrates the flame arrester assembly 41, the housing 11 and the first guide 401 and then is driven into the second guide 402, thereby fixing the pressure relief device 14 on the housing 11. In order to prevent the gas from escaping from the gap between the contact surface of the pressure relief device 14 and the housing 11, a sealing member 42 is provided between the guide assembly 40 and the housing 11, which can seal the gap between the guide assembly 40 and the housing 11. In fact, Fig.19 The sealing member 42 is disposed at the upper end of the first guide member 401, or is disposed in the groove 40a formed in the first guide member 401, and the height of the sealing member 42 is greater than or equal to the depth of the groove 40a.

[0124] refer to Figures 16 to 20A first guide rib 4011 is provided on the end surface of the first guide member 401 opposite to the second guide member 402, or the first guide rib 4011 is provided on the lower end surface of the first guide member 401; a second guide rib 4021 is provided on the end surface of the second guide member 402 opposite to the first guide member 401, or the second guide rib 4021 is provided on the upper end surface of the second guide member 402. The first guide rib 4011 and the second guide rib 4021 can define or form a plurality of guide channels 403 in the guide assembly 40. The channel entrances 4031 of the plurality of guide channels 403 are provided on the first guide member 401, for example, at a position of the first guide member 401 facing the diaphragm 43. The circumferential gap formed by the cooperation between the first guide member 401 and the second guide member 402 can serve as a channel outlet 4032. Reference Fig.19 Fig. 20 The first guide rib 4011 and the second guide rib 4021 may be cyclone-shaped ribs, so that the guide channel 403 formed by the first guide rib 4011 and the second guide rib 4021 may be a plurality of cyclone-shaped airflow paths 4033. In other embodiments, the first guide rib 4011 and the second guide rib 4021 may also be continuous or discontinuous ribs of other shapes.

[0125] refer to Fig.17 , the first distance h1 from the lower vertex of the first guide rib 4011 to the upper surface of the second guide member 402 is greater than zero, and the second distance h2 from the upper vertex of the second guide rib 4021 to the lower surface of the first guide member 401 is greater than zero, wherein the first distance h1 and the second distance h2 may be equal or unequal. Thus, after the gas enters the guide member 40 from the channel inlet 4031, it can climb over the first guide rib 4011 and the second guide rib 4021, and then flow out from the channel outlet 4032, thereby forming Fig.17 The wavy or curved airflow path shown by the thick line. In this embodiment, the contact area between the guide assembly 40 and the high-temperature gas is ensured to be large enough through multiple selections or multiple shapes of the airflow path 4033, so that the flow rate of the airflow can be effectively slowed down, and the leakage of the open flame can be further blocked.

[0126] In this embodiment, the guide component 40 can be made of metal or other materials with good heat conduction or heat absorption performance, and has a certain mechanical strength. In one implementation, when the guide component 40 is made of a metal material, its thermal conductivity is greater than or equal to 40w / (mk) and less than or equal to 500w / (mk). For example, the thermal conductivity of the first guide member 401 and / or the second guide member 402 can be 40w / (mk), 80w / (mk), 120w / (mk), 160w / (mk), 200w / (mk), 250w / (mk), 300w / (mk), 400w / (mk) or 500w / (mk), etc. In other embodiments, the guide component 40 can also be a plastic with ultra-high thermal conductivity, or graphite, or graphene, or CVD diamond film, etc. In some embodiments, the guide component 40 can also have at least a metal coating or a plastic organic coating. In some embodiments, the first guide member 401 and / or the second guide member 402 may also be a vapor chamber, such as a VC vapor chamber, a gravity vapor chamber, or a phase change vapor chamber, etc. It should be noted that the thermal conductivity coefficients of the guide assembly 40 are different when they are made of different materials, and the thermal conductivity coefficients of different materials are not listed here.

[0127] In this embodiment, if Fig.17 The second guide member 401 is provided with a needle 4022 in the same direction as the second guide rib 4021. Figure 6 The needles in the illustrated embodiment have the same function, that is, after the diaphragm 43 bulges outward to a certain extent, it can contact the needle 4022, and the needle 4022 can pierce the diaphragm 43 to release the gas.

[0128] refer to Figure 23 to Figure 25 , pressure relief components 1211 are formed on the two end surfaces of the battery module 12. A plurality of pressure relief channels 1212 are formed in the pressure relief component 1211. After thermal runaway of the battery cell 121 occurs, the generated flame or gas can be discharged from the outlet 1213 along the pressure relief channel 1212. In this embodiment, a baffle 1214 having at least one bend is provided at the outlet 1213 of the pressure relief channel 1212 to change the discharge direction of the flame or gas coming out of the outlet 1213, thereby preventing the flame from being directly sprayed on the battery cell shell of the battery cell 121. Reference Fig.19 The flow path of the airflow or flame as shown by the thick arrow line can block the flow speed of the flame or airflow at the bend of the baffle 1214 due to the effect of the baffle 1214, thereby preventing the flame or airflow from being ejected too quickly.

[0129] In some embodiments, the inner side of at least one side of the housing 11 may be provided with a high-temperature and high-voltage insulating coating, thereby increasing the high-temperature resistance of the housing 11 and preventing the battery cell 121 from burning through the housing 11 when thermal runaway occurs, causing open flames to leak out. Alternatively, a metal plate, such as an aluminum plate, may be added to the inner layer of at least one side of the housing 11 to prevent thermal runaway from burning through the housing 11. Alternatively, in other embodiments, at least one side of the housing 11 may be provided as a metal shell.

[0130] In one embodiment, a fireproof layer may also be added to the inner side of the battery compartment 24, such as a fireproof blanket, an aerogel coating, or a heat-insulating metal or plastic such as a mica sheet.

[0131] It should be noted that different implementations in this embodiment can be combined with each other to obtain better or more optimal results.

[0132] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present application.

Claims

1. A battery pack, comprising: case; A battery cell module, comprising a plurality of battery cell units, wherein the battery cell module is disposed in the housing; a pressure relief device mounted to the housing; It is characterized in that the pressure relief device is configured to at least guide high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the shell.

2. The battery pack according to claim 1, characterized in that: The pressure relief device includes: a guide assembly, which forms a guide channel for guiding the flow of the high-temperature gas.

3. The battery pack according to claim 2, characterized in that: The guide channel includes at least a plurality of cyclone-shaped airflow flow paths.

4. The battery pack according to claim 2, characterized in that: The guide assembly includes: a first guide member arranged toward the inner side of the battery pack, and a second guide member arranged opposite to the first guide member; the first guide member is provided with a channel entrance of the guide channel.

5. The battery pack according to claim 4, characterized in that: The first guide member is detachably connected to the second guide member.

6. The battery pack according to claim 4, characterized in that: The guide assembly comprises: a first guide rib is arranged on the end surface of the first guide member opposite to the second guide member; and a second guide rib is arranged on the end surface of the second guide member opposite to the first guide member.

7. The battery pack according to claim 6, characterized in that: The first guide rib and the second guide rib are configured to define and form the guide channel.

8. The battery pack according to claim 6, characterized in that: A first distance from a lower vertex of the first guide rib to an upper surface of the second guide member is greater than zero; and a second distance from an upper vertex of the second guide rib to a lower surface of the first guide member is greater than zero.

9. The battery pack according to claim 8, characterized in that: The first distance is equal to the second distance.

10. The battery pack according to claim 8, characterized in that: The first distance is not equal to the second distance.

11. The battery pack according to any one of claims 1 to 10, characterized in that: The guide assembly is made of metal material.

12. The battery pack according to claim 4, characterized in that: The pressure relief device further includes: a sealing member, which is arranged at the upper end of the first guide member to seal a gap between the guide assembly and the housing.

13. The battery pack according to claim 2, characterized in that: The pressure relief device further includes: a fire-blocking assembly disposed inside the guide assembly, configured to at least prevent an open flame generated by thermal runaway of the battery cell unit from entering the guide assembly.

14. The battery pack according to claim 13, characterized in that: The fire-blocking assembly at least comprises: a partition net provided with a plurality of fire-blocking holes.

15. The battery pack according to claim 14, characterized in that: The partition net is arranged at the innermost side of the pressure relief device.

16. The battery pack according to claim 14, characterized in that: The separator includes at least two layers of adjacently arranged metal meshes or metal foams.

17. The battery pack according to claim 16, characterized in that: The outer side of at least one layer of metal mesh or metal foam is provided with a phase change coating.

18. The battery pack according to claim 16, characterized in that: Fire extinguishing material is provided at least between adjacent metal meshes or metal foams.

19. The battery pack according to claim 13, characterized in that: The pressure relief device further comprises: a diaphragm arranged between the guide assembly and the fire-blocking assembly.

20. A battery pack comprising: case; A battery cell module, comprising a plurality of battery cell units, wherein the battery cell module is disposed in the housing; a pressure relief device mounted to the housing; It is characterized in that The pressure relief device at least comprises: The fire-blocking assembly is configured to at least prevent an open flame generated by thermal runaway of at least one battery cell unit from escaping from the housing.

21. The battery pack according to claim 20, characterized in that The pressure relief device further comprises: a guide assembly, which is configured to at least guide the high-temperature gas coming out of the fire-blocking assembly to the outside of the shell.

22. The battery pack according to claim 20, characterized in that: The fire-blocking assembly at least comprises: a partition net provided with a plurality of fire-blocking holes.

23. The battery pack according to claim 22, characterized in that: The partition net is arranged at the innermost side of the pressure relief device.

24. The battery pack according to claim 22, characterized in that: The separator includes at least two layers of adjacently arranged metal meshes or metal foams.

25. The battery pack according to claim 24, characterized in that: The outer side of at least one layer of metal mesh or metal foam is provided with a phase change coating.

26. The battery pack according to claim 24, characterized in that: Fire extinguishing material is provided at least between adjacent metal meshes or metal foams.

27. The battery pack according to claim 21, characterized in that: The pressure relief device further comprises: a diaphragm arranged between the guide assembly and the fire-blocking assembly.

28. A battery pack comprising: case; A battery cell module, comprising a plurality of battery cell units, wherein the battery cell module is disposed in the housing; A pressure relief device, disposed on the housing; It is characterized in that The pressure relief device at least comprises: A fire-blocking assembly, located at one end of the pressure relief device close to the battery module, the fire-blocking assembly being configured to at least prevent an open flame generated by thermal runaway of at least one battery unit from escaping from the housing; A guide component is located at the other end of the pressure relief device away from the battery cell module, and the guide component is configured to at least guide the high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the shell.

29. The battery pack according to claim 28, characterized in that: The pressure relief device further includes: a sealing member, which is arranged at the upper end of the guide assembly to seal a gap between the guide assembly and the housing.

30. The battery pack according to claim 28, characterized in that: The guide assembly forms a guide channel for guiding the flow of the high-temperature gas.

31. The battery pack according to claim 29, characterized in that: The channel inlet of the guide channel is arranged to face the fire-blocking assembly.

32. The battery pack according to claim 29, characterized in that: The guide channel includes a plurality of cyclone-shaped airflow flow paths.

33. The battery pack according to claim 28, characterized in that: The fire-blocking assembly at least comprises: a partition net provided with a plurality of fire-blocking holes.

34. The battery pack according to claim 28, characterized in that: The pressure relief device further comprises: a diaphragm arranged between the guide assembly and the fire-blocking assembly.

35. An electric tool comprising: chassis; A motor, disposed in the housing; A battery installation portion, configured to install a battery pack for supplying power to at least the motor; The battery pack comprises: case; A battery cell module, comprising a plurality of battery cell units, wherein the battery cell module is disposed in the housing; A pressure relief device, disposed on the housing; Features: The pressure relief device is configured to at least guide high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the housing; and At least an open flame generated by thermal runaway of at least one battery cell unit is prevented from escaping from the housing.

36. An outdoor wheeled tool comprising: Frame; Travel wheels, configured to support the frame; A motor, configured to at least drive the walking wheels to walk; A battery compartment, used to accommodate a battery pack, wherein the battery pack at least supplies power to the motor; The battery pack comprises: case; A battery cell module, comprising a plurality of battery cell units, wherein the battery cell module is disposed in the housing; a pressure relief device mounted to the housing; Wherein, the pressure relief device is configured to at least guide high-temperature gas generated by thermal runaway of at least one battery cell unit to be discharged from the shell.

37. The outdoor wheeled tool according to claim 36, characterized in that: The pressure relief device includes: a guide assembly, which forms a guide channel for guiding the flow of the high-temperature gas.

38. The outdoor wheeled tool according to claim 37, characterized in that: The pressure relief device further includes: a fire-blocking assembly disposed inside the guide assembly, configured to at least prevent an open flame generated by thermal runaway of the battery cell unit from entering the guide assembly.

39. The outdoor wheeled tool according to claim 38, characterized in that: The pressure relief device further comprises: a diaphragm arranged between the guide assembly and the fire-blocking assembly.

40. The outdoor wheeled tool according to claim 37, wherein: The pressure relief device further includes: a sealing member, which is arranged at the upper end of the guide assembly to seal a gap between the guide assembly and the housing.

41. The outdoor wheeled tool according to claim 36, characterized in that: The battery compartment is provided with an exhaust port corresponding to the pressure relief device.

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