Electric tool and battery pack

Abstract

The invention discloses an electric tool and a battery pack, and the battery pack comprises a shell; each battery cell module comprises a plurality of battery cell units, and the convergence surface of the positive electrode and the convergence surface of the negative electrode of each battery cell unit are two polarity end surfaces of the battery cell module; and the heat insulation part is at least arranged between the polar end surfaces of the two adjacent battery cell modules.

Description

Technical Field

[0001] This application relates to energy storage, and more particularly to a power tool and a battery pack. Background Art

[0002] Currently, lithium batteries are increasingly widely used. At the same time, the safety of their application products has also received more and more attention. However, thermal runaway events caused by cell failures occur frequently, causing significant harm and impact to people's production and life.

[0003] This section provides background information related to this application, and this background information is not necessarily prior art. Summary of the Invention

[0004] An object of this application is to solve or at least mitigate part or all of the above problems. To this end, an object of this application is to provide a battery pack with higher safety performance and a power tool using this battery pack.

[0005] To achieve the above object, this application adopts the following technical solutions: A power tool includes: a tool body; a battery pack mounting portion provided on the tool body for mounting at least one battery pack; the battery pack includes: a housing; at least two cell modules, each cell module including a plurality of cell units, and the converging surfaces of the positive electrodes and the converging surfaces of the negative electrodes of the cell units are two polar end faces of the cell module; a heat insulation member provided at least between the polar end faces of two adjacent cell modules.

[0006] In one embodiment, the heat insulation member is provided on the two polar end faces of the cell module.

[0007] In one embodiment, the battery pack further includes an exhaust housing provided on at least one of the polar end faces of the cell module; the heat insulation member is provided between the polar end face of the cell module and the exhaust housing.

[0008] In one embodiment, the heat insulation member is provided inside the exhaust housing.

[0009] In one embodiment, at least part of the housing of the exhaust housing forms the heat insulation member.

[0010] In one embodiment, the heat insulation member includes at least one of a metal plate, a thermally conductive plastic plate, a composite plate, a plate coated with a heat insulation material, a plate coated with a phase change material, or a mica plate.

[0011] In one embodiment, the battery pack further includes a reinforcing member; the reinforcing member is provided on the inner side and / or the outer side of the housing opposite to the polar end face.

[0012] In one embodiment, the reinforcing member is fixed to the housing.

[0013] In one embodiment, the reinforcing member is embedded in the housing.

[0014] In one embodiment, at least a part of the inner side and / or the outer side of the housing is provided with at least one layer of flame retardant coating.

[0015] In one embodiment, the battery pack further includes a fixing member; the fixing member is arranged to penetrate through at least two of the battery cell modules and then fix the battery cell modules to the housing.

[0016] In one embodiment, at least one layer of flame retardant wrapping layer 1211 is provided on the outer layer of at least one of the battery cell units.

[0017] A battery pack, comprising: a housing; at least two battery cell modules, each of the battery cell modules including a plurality of battery cell units, the converging surfaces of the positive electrodes and the converging surfaces of the negative electrodes of the battery cell units being two polar end faces of the battery cell module; a heat insulating member disposed at least between the polar end faces of two adjacent battery cell modules.

[0018] In one embodiment, the heat insulating member is further disposed on any one of the polar end faces of the battery cell module.

[0019] A battery pack, comprising: a housing; a battery cell module including a plurality of battery cell units, the battery cell module being disposed in the housing; a pressure relief device detachably mounted to the housing; the pressure relief device being configured to at least guide high-temperature gas generated by thermal runaway of at least one battery cell unit out of the housing; wherein, the pressure relief device is formed with a guiding channel for guiding the high-temperature gas; the battery pack further includes: a protective member at least covering an outlet of the guiding channel and forming a communication channel for communicating the outlet of the channel with the outside.

[0020] In one embodiment, the protective member is mounted to the housing and completely covers the pressure relief device.

[0021] In one embodiment, on the battery pack, the pressure relief device does not protrude beyond the protective member. Description of the Drawings

[0022] Figure 1 is a perspective view of various outdoor wheeled devices in an embodiment proposed by the present application; Figure 2 is a perspective view of a riding lawn mower in an embodiment proposed by the present application; Figure 3 is a perspective view of a riding lawn mower in another embodiment proposed by the present application; Figure 4 is a perspective view of a battery pack according to an embodiment proposed by the present application; Figure 5 is Figure 4 an exploded view of a partial structure of the battery pack in Figure 6 is a perspective view of a battery pack according to an embodiment proposed by the present application; Figure 7 is a perspective view of a battery pack according to an embodiment proposed by the present application; Figure 8a is a schematic structural diagram of the position of a sampling board in an embodiment proposed by the present application; Figure 8b is a schematic diagram of a flame-retardant wrapping layer provided on the surface of a battery cell unit in an embodiment proposed by the present application; Figure 9 is a structural diagram of battery cells and cell brackets inside a battery pack according to an embodiment; Figure 10 is a structural diagram of battery cells and cell brackets inside a battery pack according to another embodiment; Figure 11 is a schematic diagram of a cell connection tab according to an embodiment proposed by the present application; Figure 12 is a structural diagram of a pressure relief device of a battery pack according to an embodiment proposed by the present application; Figure 13 is Figure 12 an exploded view of the pressure relief device in Figure 14 is an exploded view of a pressure relief device according to another embodiment proposed by the present application; Figure 15 is a perspective view of one perspective of a battery pack including at least an energy conversion device according to an embodiment; Figure 16 is a perspective view of another perspective of a battery pack including at least an energy conversion device according to an embodiment Figure 17a and Figure 17b is a structural diagram of a battery pack with a compartment according to an embodiment; Figure 18 is a schematic diagram of a control circuit inside a battery pack according to an embodiment; Figure 19 is a schematic diagram of a battery compartment and a battery pack of an outdoor wheeled tool; Figure 20 is a structural diagram of a battery compartment according to an embodiment proposed by the present application; Figure 21 is Figure 20 a schematic diagram of the bottom plate of the battery compartment in Figure 22It is a structural diagram of a battery pack and a pressure relief device in an embodiment; Figure 23 It is a sectional view of the pressure relief device installed on the battery pack housing in an embodiment; Figure 24 It is a sectional view of the pressure relief device installed on the battery pack housing in an embodiment; Figure 25 It is a structural diagram of the pressure relief device in an embodiment proposed by the present application; Figure 26 It is proposed by the present application Figure 25 An exploded view of the pressure relief device at an angle in; Figure 27 It is proposed by the present application Figure 25 An exploded view of the pressure relief device at another angle in; Figure 28 It is a sectional view of the pressure relief device in an embodiment proposed by the present application; Figure 29 It is a sectional view of the pressure relief device in an embodiment proposed by the present application; Figure 30 It is a sectional view of a battery pack with a protective member provided in an embodiment proposed by the present application; Figure 31 It is an exploded view of a partial structure inside the battery pack in an embodiment proposed by the present application; Figure 32 It is an exploded view of a partial structure inside the battery pack in another embodiment proposed by the present application; Figure 33 It is a three-dimensional view of the internal exhaust housing of the battery pack in an embodiment proposed by the present application; Figure 34 It is a schematic diagram of the intake part of the internal exhaust passage of the battery pack in an embodiment proposed by the present application; Figure 35a and Figure 35b It is a partial structure exploded view of a battery cell module with a pressure relief component provided in an embodiment proposed by the present application; Figure 36 It is a structural diagram of a battery cell module with a pressure relief component provided in an embodiment proposed by the present application; Figure 37 It is a sectional view of a battery cell module with a pressure relief component provided in an embodiment proposed by the present application; Figure 38 It is a schematic diagram of the structure for fixing the battery cell module in an embodiment proposed by the present application; Figure 39 It is a partial structure exploded view of a battery cell module in an embodiment proposed by the present application; Figure 40 It is a sectional view of a battery cell module in an embodiment proposed by the present application; Figure 41 is a cross-sectional view of a battery cell module in an embodiment proposed by the present application; Figure 42 is an exploded view of a partial structure of a battery cell module in an embodiment proposed by the present application; Figure 43 is Figure 42 an exploded view of a partial structure of the battery cell module in Figure 44 is Figure 42 a cross-sectional view of the battery cell module in Figure 45 is an exploded view of a partial structure of a battery cell module in an embodiment proposed by the present application; Figure 46 is Figure 45 a cross-sectional view of the battery cell module in Figure 47 is Figure 45 an exploded view of a partial structure of the battery cell module in. Detailed implementation manners

[0023] Before explaining any implementation manner of the present application in detail, it should be understood that the present application is not limited to the structural details and component arrangements described in the following description or shown in the above drawings.

[0024] In the present application, the terms "include", "comprise", "have" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the presence of additional identical elements in the process, method, article or device including such element.

[0025] In the present application, the term "and / or" is an associative relationship describing associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the present application, the character " / " generally represents an "and / or" relationship between the associated objects before and after.

[0026] In this application, the terms "connected", "combined", "coupled", and "mounted" can be direct connections, combinations, couplings, or mountings, or indirect connections, combinations, couplings, or mountings. For example, a direct connection means that two parts or components are connected together without an intermediate member, and an indirect connection means that two parts or components are respectively connected to at least one intermediate member, and these two parts or components are connected through the intermediate member. In addition, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, and may include electrical connections or couplings.

[0027] In this application, those of ordinary skill in the art will understand that relative terms used in combination with a quantity or condition (such as "about", "approximately", "substantially", etc.) are intended to include the stated value and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances resulting from manufacturing, assembly, use, etc. associated with a particular value. Such terms should also be considered to disclose a range defined by the absolute values of two endpoints. Relative terms may refer to a plus or minus a certain percentage (such as 1%, 5%, 10% or more) of the indicated value. Numerical values without the use of relative terms should also be disclosed as specific values with tolerances. In addition, when expressing a relative angular positional relationship (such as substantially parallel, substantially perpendicular), "substantially" may refer to a plus or minus a certain number of degrees (such as 1 degree, 5 degrees, 10 degrees or more) based on the indicated angle.

[0028] In this application, those of ordinary skill in the art will understand that the functions performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0029] In this application, the orientation terms such as "upper", "lower", "left", "right", "front", "rear", etc. are described based on the orientation and positional relationship shown in the drawings, and should not be construed as a limitation on the embodiments of this application. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element. It should also be understood that orientation terms such as the upper side, lower side, left side, right side, front side, rear side, etc. not only represent the positive orientation, but can also be understood as the side orientation. For example, the lower side can include directly below, lower left, lower right, lower front, and lower rear, etc.

[0030] In this embodiment, a variety of different types of outdoor wheeled devices 200 can be powered by the battery pack 100. Figure 1Illustrates several common wheeled devices, 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 other various common wheeled devices that can be powered by the battery pack 100 are also within the protection scope of this application, such as a mobile power supply device (English translation: powerstation), a wheeled fan, a wheeled lighting device, a wheeled hair dryer, a cleaning vehicle, etc. In this embodiment, the outdoor wheeled device 200 can also be referred to as an outdoor wheeled tool 200.

[0031] In the following embodiments, Figure 1 the riding lawn mower 200a shown in Figure 2 is taken as an example for illustration. Referring to

[0032] the riding lawn mower 200a described above, it can at least include a frame 21, traveling wheels 22 that support the frame 21, a motor 23 that can at least drive the traveling wheels 22, and a battery compartment 24 for accommodating the battery pack 100. The lawn mower 200a can also include a seat 25 and an operation assembly 26 provided on the frame 21, where the operation assembly 26 can include an operation lever 261, or a steering wheel 262, or a pedal 263, etc. The lawn mower 200a can also include a cutting assembly 27 provided at the lower end of the frame 21, or a lighting device 28 provided at the front end of the frame 21, etc.

[0032] In some embodiments, the battery compartment 24 can be provided at the rear end, or the front end, or the bottom end, or the side of the frame 21. Figure 2 In the shown lawn mower 200a, the battery compartment 24 is provided at the front end of the frame 21. Figure 3 In the shown lawn mower 200a, the battery compartment 24 is provided at the rear end of the frame 21. The positions of the battery compartment 24 provided on the lawn mower 200a or other wheeled tools will not be listed one by one here.

[0033] 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 installed on the frame 21, that is to say, the frame 21 can form a battery compartment installation part (not shown) to install the battery compartment 24. In one embodiment, the lawn mower 200a can include a battery compartment 24 integrally formed with the frame 21, and at the same time also include a battery compartment 24 detachably installed on the frame 21. In one embodiment, the battery pack 100 can be detachably installed in the battery compartment 24, or can be fixedly installed in the battery compartment 24 or said to be built-in in the battery compartment 24.

[0034] In one embodiment, the battery compartment 24 is at least partially made of a metal material.

[0035] In this embodiment, the battery compartment 24 can accommodate one or more battery packs 100. This embodiment does not specifically limit the discharge sequence or discharge method of multiple battery packs 100 when powering the lawn mower 200a in the battery compartment 24. Exemplarily, 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 sequentially, etc. Or one battery pack in the battery compartment 24 can discharge to other battery packs.

[0036] In one embodiment, the battery pack 100 can be detached from the lawn mower 200a and used to power other power tools, such as handheld tools like drills, pruning machines, sanders, etc., can also power other wheeled power tools like snow blowers, and can also power push-type power tools like push-type lawn mowers and push-type snow blowers. It can also power bench tools, or gardening tools, or decorating tools, or vegetation care tools, or different types of tools like drills and saws. That is to say, the battery pack 100 can be at least a battery pack that is common to multiple power tools.

[0037] Reference Figures 4 to 8a The shown battery pack 100 at least includes a housing 11, a battery cell module 12, and a terminal assembly 13. Among them, the housing 11 can be as Figure 3 and Figure 4 shown and includes a barrel 1101 and an upper cover 1102. The barrel 1101 can be entirely composed of plastic parts. In one implementation, a reinforcing member 1103 can be provided on the side of the barrel 1101, and the extending direction of the reinforcing member 1103 is basically perpendicular to the longitudinal extending direction of the battery cell unit 121. It can be understood that the reinforcing member 1103 is basically parallel to the two polar end faces 126 of the battery cell module 12. In this application, the two polar end faces of the battery cell module 12 can be understood as the two end faces of the battery cell module 12 that respectively converge the positive and negative electrodes of the battery cell units 121, that is, one end face where all the positive electrodes of the battery cell units 121 in a battery cell module 12 are located is one polar end face of the battery cell module 12, and the end face where all the negative electrodes of the battery cell units 121 are located is the other polar end face of the battery cell module 12. Unless otherwise specified, the two end faces or the two polar end faces of the battery cell module 12 mentioned in this application all refer to the above-mentioned end faces. The other faces of the battery cell module 12 except the above two polar end faces can be called the side faces of the battery cell module 12, such as the upper side face, the lower side face, or the left side face, etc.

[0038] In one embodiment, the reinforcing member 1103 can be installed on the side of the barrel 1101 by means of screws or the like, and a seal, such as sealant or sealing strip, is provided at the joint of the reinforcing member 1103 and the barrel 1101. In one embodiment, the reinforcing member 1103 can also be snapped or embedded into the side of the barrel 1101, or can be built into a plastic part on the side of the barrel 1101. For example, the reinforcing member 1103 can be embedded into the side of the barrel 1101 by insert injection molding. In this embodiment, the reinforcing member 1103 can be made of plastic material, metal material or other fire-retardant materials.

[0039] The upper cover 1102 can be formed of a plastic part, and Figure 5 the recessed handle 1106 as shown in a can be provided on the upper cover 1102. That is to say, the upper cover 1102 can be recessed inward to form a handle part for the user to lift the battery pack 100. Or a Figure 5 lifting handle 1106 as shown in b is installed on the upper cover 1102.

[0040] In one embodiment, the housing 11 can also be as Figure 7 shown, including a lower cover 1104, a fence 1105 and an upper cover 1102. The housing 11 as a whole can be made of plastic parts. A lifting handle or a recessed handle can be provided on the upper cover 1102. By reasonably arranging the handle 1106, the overall size of the battery pack 100 can be reduced. For example, if the recessed handle is on the outside, the control board 165 can be hidden in the upper cover 1102, so that the height can be reduced. In one embodiment, at least the upper cover 1102 of the battery pack 100 can be made of metal material, such as pure metal or alloy metal, which can enhance the upper cover 1102's ability to withstand high temperature and high pressure.

[0041] In one embodiment, the housing 11 can be made of a flame-retardant material, that is, the housing 11 itself can prevent the spread of combustion. Or at least the barrel 1101 is made of a flame-retardant material, or at least the reinforcing member 1103 is made of a flame-retardant material. In this embodiment, the housing 11 or the barrel 1101 can withstand high temperature and high pressure gas with a pressure greater than or equal to 1 MPa and a high temperature of at least 300 °C. Therefore, when the battery cell unit 121 undergoes thermal runaway, the housing 11 prevents the spread of thermal runaway to a certain extent and reduces the harm of thermal runaway.

[0042] In one embodiment, one or more layers of flame-retardant coatings (not shown) may be provided on the inner side and / or the outer side of the housing 11, or at least on the outer side and / or the inner side of the barrel 1101 facing the polar end face 126 of the battery cell module 12. The provided flame-retardant coating may be an intumescent flame retardant, or a fireproof coating, or a fireproof plastic laminate, etc. In one embodiment, a flame-retardant coating formed by two-color injection molding of high-temperature-resistant plastic and ordinary flame-retardant plastic may be used on the inner side and / or the outer side of the housing 11, or the housing 11 may be directly formed by two-color injection molding of high-temperature-resistant plastic and ordinary flame-retardant plastic.

[0043] In one embodiment, the flame-retardant material constituting the housing 11, or the flame retardant constituting the flame-retardant coating, or at least part of the material constituting the battery cell support 16 may be a fast-curing epoxy prepreg (FR), or a flame-retardant continuous fiber plastic (CFT), or may be a composite material supported by multiple fibers with aramid as the main body.

[0044] The battery cell module 12 may include a plurality of battery cell units 121 for storing electric energy. In this embodiment, the battery 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 battery cell unit 121 may be a single-tab battery, or a double-tab battery, or a full-tab battery. In this embodiment, at least part of the battery cell units 121 are lithium iron phosphate battery cells. Or the positive electrode material of at least part of the battery cell units 121 is a sodium ion battery cell. Or the positive electrode material of at least part of the battery cell units 121 is a capacitor battery. Or the positive electrode material of at least part of the battery cell units 121 is a lithium ion battery cell, such as a ternary lithium battery cell. Or the positive electrode material of at least part of the battery cell units 121 is a super capacitor. Or the battery pack 100 mixes multiple battery cells of different materials or properties. In one embodiment, the battery cell unit 121 may be a cylindrical 18650 battery cell (18 mm in diameter and 65 mm in length), or a cylindrical 14500 battery cell (14 mm in diameter and 50 mm in length), or a 14650 battery cell (14 mm in diameter and 65 mm in length), or a 17500 battery cell (17 mm in diameter and 50 mm in length), or a 17670 battery cell (17 mm in diameter and 67 mm in length), or an 18500 battery cell (18 mm in diameter and 50 mm in length), or a 26650 battery cell (26 mm in diameter and 65 mm in length), or a 26700 battery cell (26 mm in diameter and 70 mm in length), etc.

[0045] The terminal assembly 13 may include a discharge interface capable of connecting to an electrical device, or a charging interface capable of connecting to a charging device, or a charge-discharge interface capable of connecting to both an electrical device and a charging device. In this embodiment, the type or position of the terminal assembly 13 is not limited.

[0046] Reference Figure 8a , the battery pack 100 further includes a sampling board 113, which is configured to collect the voltage of one or more cell units 121 or the voltage of the cell module 12, and can transmit the collected voltage to the terminal assembly 13. In this embodiment, the sampling board 113 may be disposed on the side of the cell module 12, and the extending direction of the sampling board 113 is substantially parallel to the longitudinal extending direction of the cell unit 121. In one embodiment, the sampling board 113 is disposed on the side of the cell module 12 close to the terminal assembly 13 to facilitate electrical connection with the terminal assembly 13. In one embodiment, the number of the sampling boards 113 may be the same as the number of the cell modules 12. In one embodiment, the sampling board 113 may be an epoxy board. In one embodiment, the sampling board 113 may be fixed to the side of the cell module 12 by screws, and the cell connection piece 116 may be welded to the sampling board 13.

[0047] In one embodiment, such as Figure 8bAs shown, at least one layer of flame-retardant wrapping layer 1211 may be provided on the outer layer of the battery cell unit 121 to wrap at least part of the side surface of the battery cell unit 121 or wrap all the side surfaces of the battery cell unit. Or it can be understood that the flame-retardant wrapping layer 1211 is provided on the surface of the battery cell unit 121 except for the positive electrode and the negative electrode. In one embodiment, the flame-retardant wrapping layer 1211 may be formed of a flame-retardant coating material with a variable thermal conductivity. For example, at normal temperature or room temperature, the thermal conductivity of the flame-retardant wrapping layer 1211 is greater than or equal to 0.5 W / m·K, and when the temperature is greater than the preset temperature, the thermal conductivity of the flame-retardant wrapping layer 1211 is less than or equal to 0.02 W / m·K. The normal temperature or room temperature herein may be a temperature range, such as a temperature range within 0°C - 500°C, or a temperature range within 10°C - 300°C, or a temperature range within 10°C - 200°C, or a temperature range within 10°C - 100°C, or a temperature range within 10°C - 50°C, etc. The preset temperature may also be a temperature range, such as a temperature greater than or equal to 500°C, or a temperature greater than or equal to 400°C, etc. That is to say, when the temperature is greater than normal temperature or room temperature, the flame-retardant wrapping layer 1211 has good heat insulation performance, and can well block the high temperature generated by the battery cell unit 121 that has experienced thermal runaway within the battery cell unit itself, reducing the heat transfer from the side surface of the battery cell unit 121 to other adjacent battery cell units 121 and reducing the impact on the adjacent battery cell units 121. In one embodiment, a common flame-retardant material with a fixed thermal conductivity or an undefined thermal conductivity may also be used to form the flame-retardant wrapping layer 1211.

[0048] In one embodiment, the flame-retardant wrapping layer 1211 on the surface of the battery cell unit 121 may also be formed of a resin material, such as a water-absorbing resin. To avoid short-circuiting the positive and negative end faces of the battery cell unit 121, when the water-absorbing resin surrounds the surface of the battery cell unit 121, it is necessary to seal the positive and negative end faces of the battery cell unit 121, such as using a sealant for sealing. In this embodiment, the coefficient of expansion ratio of the water-absorbing resin is greater than or equal to 10 and less than or equal to 9000. After absorbing water, the resin has high insulation and flame-retardant properties and a relatively large internal resistance. When the battery cell unit 121 experiences thermal runaway, the water-absorbing resin can isolate the heat transfer and avoid affecting the adjacent battery cell units 121. When the battery pack 100 is operating normally, the water-absorbing resin can take away part of the heat dissipated by the battery cell unit 121 to achieve the purpose of controlling the surface temperature of the battery cell unit 121.

[0049] In one embodiment, all the battery cell units 121 included in the battery cell module 12 generally include outer battery cells and inner battery cells in their arrangement. The outer battery cell units 121 are the outermost ring of battery cells in a battery cell module 12. If the cross-section of the battery cell module 12 is approximately square, the outer battery cell units 121 can be the battery cells arranged along the sides of the square, and the inner battery cell units 121 can be all the battery cell units 121 in the battery cell module 12 except for the outer battery cells. It can be understood that the heat generation of the inner battery cell units 121 in the battery cell module 12 is higher than that of the outer battery cell units 121, and the heat dissipation performance of the inner battery cell units 121 is worse than that of the outer battery cell units 121. Basically, the probability of thermal runaway of the innermost battery cell units 121 in the battery cell module 12 is greater.

[0050] In order to reduce the probability of thermal runaway of the inner battery cell units or prevent the inner battery cell units 121 from having thermal runaway, a flame-retardant wrapping layer 1211 is provided outside at least some of the inner battery cell units 121. In some embodiments, the flame-retardant wrapping layer 1211 can be provided outside the inner battery cell units 121 within a preset range centered on the geometric center of the battery cell module 12. Among them, the preset range can be the size of at least the diameter of one battery cell unit 121, etc. That is to say, the battery cell unit 121 located at the geometric center of the battery cell module 12 is provided with the flame-retardant wrapping layer 1211, or the battery cell unit 121 at the geometric center of the battery cell module 12 and one or two or more circles of inner battery cell units 121 surrounding this battery cell unit 121 are respectively provided with the flame-retardant wrapping layer 1211.

[0051] In this embodiment, providing the flame-retardant wrapping layer 1211 can at least conduct the heat generated by the battery cell unit 121 in the early stage before the battery cell unit 121 has thermal runaway, and has a certain hindering effect on the further thermal runaway of the battery cell unit 121. When the battery cell unit 121 has thermal runaway, the temperature of the battery cell unit 121 rises sharply, and the flame-retardant wrapping layer 1211 can become a heat-insulating material under high-temperature conditions, playing a role of heat insulation and flame retardancy for this battery cell unit 121. It can prevent the open fire generated by the thermal runaway of this battery cell unit 121 from spreading to adjacent other battery cell units, or reduce the influence of high temperature on other adjacent surrounding battery cell units.

[0052] In this embodiment, the flame-retardant wrapping layer 1211 can be formed of ordinary high-flame-retardant materials, which can be intumescent flame retardants, or fireproof coatings, or fireproof plastic laminates, etc. For example, fast-curing epoxy prepreg (FR), or flame-retardant continuous fiber plastic (CFT), or can be a composite material supported by various fibers with aramid as the main body.

[0053] 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 can be understood that the nominal voltage of the battery pack 200 can be greater than or equal to 20V and less than or equal to 100V, or the nominal voltage of the battery pack 100 is greater than or equal to 36V and less than or equal to 80V, or the nominal voltage of the battery pack 100 can be greater than or equal to 40V and less than or equal to 60V. Or the nominal voltage of the battery pack 100 can be greater than or equal to 100V and less than or equal to 800V. It can be understood that the nominal voltage of the battery pack 100 can 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 device 100 using multiple battery packs 100 can accommodate the voltage platforms of other battery packs, thereby increasing the total energy of the battery packs in the wheeled device. When at least two battery packs 100 are arranged in the outdoor wheeled device 200, the nominal voltages of the at least two battery packs 100 can be the same or different.

[0054] 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. Or, the weight energy density of the battery pack 200 is greater than or equal to 150 wh / kg and less than or equal to 200 wh / kg. The volume energy density of the battery pack 200 is greater than or equal to 100 wh / L and less than or equal to 200 wh / L. Or, the volume energy density of the battery pack 200 is greater than or equal to 150 wh / L and less than or equal to 200 wh / L. Or, the volume energy density of the battery pack 200 is greater than or equal to 90 wh / L and less than or equal to 200 wh / L. Or, the volume energy density of the battery pack 200 is greater than or equal to 100 wh / L and less than or equal to 150 wh / L. The higher weight energy density or volume energy density enables the outdoor wheeled device 100 to obtain more energy when installing battery packs of the same volume or weight, ensuring the endurance of the wheeled device. For example, it can ensure the demand for the wheeled device to work outdoors for half a day, and can also take into account the requirements of the size or load of the device itself.

[0055] 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. Or, 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. Or 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. Or 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. Or 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. Or 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. Thus, when at least one battery pack 100 in the outdoor wheeled device 200 is fully charged, the outdoor wheeled device 200 can mow the grass for 4 to 6 hours through the battery pack 100.

[0056] Reference Figure 9 and Figure 10, the battery pack 100 further includes a battery cell support 16. The battery cell support 16 may include a surrounding portion 161 surrounding the battery cell unit 121, and a first end cap 162 and a second end cap 163 covering both ends of the surrounding portion 161. The surrounding portion 161 forms a plurality of battery cell accommodation cavities 164 inwardly, and each battery cell accommodation cavity 164 can accommodate one battery cell unit 121. It can also be considered that a surrounding portion 161 and the first end cap 162 and the second end cap 163 at both ends thereof together constitute the battery cell accommodation cavity 164. The plurality of battery cell accommodation cavities 164 and other parts of the battery cell support 16 connecting the plurality of battery cell accommodation cavities 164 together constitute the battery cell support 16. The cylindrical space formed by the surrounding portion 161 can also be used as the battery cell accommodation cavity 164. In this embodiment, the plurality of battery cell accommodation cavities 164 are closely adjacent to each other to form a battery cell support 16 for accommodating a plurality of battery cell units 121.

[0057] In this embodiment, the first end cap 162 and the second end cap 163 are semi-closed end caps, which can at least hold the battery cell unit 121 in the battery cell accommodation cavity 164 and expose the positive or negative electrode of the battery cell unit 121 outside the battery cell accommodation cavity 164, so that the battery cell unit 121 can be electrically connected to the control board 165 in the battery pack 100 or different battery cell units 121 can be connected. In this embodiment, the control board 165 can be arranged at the upper end of the battery cell support 16 or at the upper part of the accommodation cavity formed by the housing 11.

[0058] It can be understood that the battery pack 100 may further include a battery cell connection piece 166, such as Figure 9 The battery cell connection piece 166 is used to electrically connect the positive electrodes of at least two battery cell units 121 or electrically connect the negative electrodes of at least two battery cell units 121. In this embodiment, the battery cell connection piece 166 can be arranged on the first end cap 162 and the second end cap 163, and the shape of the battery cell connection piece 166 is related to the number of battery cell units 121 it connects. For example, the battery cell connection piece 166 is basically a vertical strip, which can electrically connect the positive electrodes of a column of battery cell units 121 or electrically connect the negative electrodes of a column of battery cell units 121.

[0059] Reference Figure 11As shown, the cell connection piece 166 can be electrically coupled to the positive or negative electrode end of the cell unit 121 through the connection electrode piece 1661. In this embodiment, the thickness of the transition connection part 1662 between the connection electrode piece 1661 and the cell connection piece 166 is less than the thickness of the cell connection piece 166 and / or the connection electrode piece 1661. In other embodiments, the width of the transition connection part 1662 can be less than the width of the cell connection piece 166 and / or the connection electrode piece 1661, or the melting point of the material of the transition connection part 1662 is lower than the melting point of the cell connection piece 166 and / or the connection electrode piece 1661. Thus, when thermal runaway or other problems occur in the cell unit 121, the electrical connection between the cell connection piece 166 and the cell unit 121 can be melted faster, or the transition connection part 1662 can be broken by the high-temperature and high-pressure gas during thermal runaway, which can avoid short circuit and also prevent the cell unit 121 with thermal runaway from affecting other cell units 121 through the cell connection piece 166.

[0060] In one implementation, a cell bracket 16 can be divided into two detachable bracket parts along a direction perpendicular to the extending direction of the cell accommodation cavity 164. After the cell unit 121 is placed in the cell accommodation cavity 164, the two bracket parts can be snapped together to hold the cell unit 121 in the cell accommodation cavity 164.

[0061] In this embodiment, each cell accommodation cavity 164 accommodates one cell unit 121, and adjacent cell units 121 do not directly contact each other and are separated by the cavity wall of the cell accommodation cavity 164. Thus, when a slight thermal runaway occurs in each cell unit 121 within its respective cell accommodation cavity 164, it will not affect the adjacent cell units 121. The so-called slight thermal runaway means that the degree of thermal runaway of the cell unit 121 can be blocked by the cavity wall of the cell accommodation cavity 164 and will not break through the cavity wall and spread to the adjacent cell accommodation cavity 164. In this embodiment, the heat distortion temperature of the cell bracket 16 is greater than or equal to 500 °C. Or, the heat distortion temperature of the cell bracket 16 is greater than or equal to 550 °C. Or, the heat distortion temperature of the cell bracket 16 is greater than or equal to 600 °C. Or, the heat distortion temperature of the cell bracket 16 is greater than or equal to 650 °C. Exemplarily, if the thermal runaway temperature of the cell unit 121 is less than 500 °C, the cavity wall of the cell accommodation cavity 164 will not undergo heat distortion, thereby avoiding damage to multiple cell units 121 in the battery pack 100 caused by the thermal runaway of one cell unit 121 and reducing the harm of thermal runaway of the battery pack 100.

[0062] In this embodiment, the density of the battery cell bracket 16 is greater than or equal to 1 g / cm³. It is understandable that the density of the battery cell bracket 16 can be greater than or equal to 1 g / cm³ and less than or equal to 5 g / cm³, or the density of the battery cell bracket 16 can be greater than or equal to 1.5 g / cm³ and less than or equal to 2 g / cm³, or the density of the battery cell bracket 16 can be greater than or equal to 1.5 g / cm³ and less than or equal to 4 g / cm³.

[0063] In this embodiment, the battery cell bracket 16 is formed of a flame-retardant thermoplastic material that inhibits the spread of thermal runaway, and the material can at least include polyamide, lubricant, antioxidant, surfactant, toughening agent, non-toxic flame retardant, reinforcing material, and reinforcing modifier. Among them, the polyamide is nylon 6, nylon 66, or a combination thereof, and the weight percentage of the polyamide can be 20%-50%. The weight percentage of the lubricant can be 0.1%-3%. The weight percentage of the toughening agent can be 0.1%-30%. The non-toxic flame retardant can at least include metal polyphosphates, melamine phosphates, melamine cyanurate, phosphate esters, borates, or a mixture thereof, and the weight percentage thereof can be 3%-50%. The reinforcing modifier can be metal oxides and their derivatives, metal hydroxides and their derivatives, or metal silicates, and the weight percentage of the reinforcing modifier is 8%-40%. The reinforcing material can be glass fiber, mineral fiber, or kaolin, and the weight percentage of the reinforcing material is 0 to 25%.

[0064] In this embodiment, the heat conduction coefficient of the battery cell bracket 16 can vary with different temperatures. For example, in the case of the first temperature, the heat conduction coefficient (i.e., the thermal conductivity) of the battery cell bracket 16 is greater than or equal to 0.5 W / m-K, and in the second temperature, the heat conduction coefficient of the battery cell bracket 16 is less than or equal to 0.05 W / m-K. Among them, the first temperature can be a temperature range, for example, it can be 0°C - 500°C, and the second temperature can also be a temperature range, for example, it can be greater than 500°C. That is to say, when the temperature is relatively low, the battery cell bracket 16 has a good heat dissipation effect, enabling the normal charging and discharging of the battery pack 100; while when the temperature is relatively high and the battery cell unit 121 in the battery pack 100 undergoes thermal runaway or is about to undergo thermal runaway, the battery cell bracket 16 has a high effect of preventing heat conduction, preventing the battery cell unit 121 from being affected by its adjacent thermally runaway battery cell unit 121. In other embodiments, the heat conduction coefficient of the battery cell bracket 16 at the first temperature and / or the second temperature can be adjusted by modifying the constituent materials of the battery cell bracket 16. For example, at the first temperature, the heat conduction coefficient of the battery cell bracket 16 is greater than or equal to 0.5 W / m-K, and at the second temperature, the heat conduction coefficient of the battery cell bracket 16 is less than or equal to 0.03 W / m-K. Or, at the first temperature, the heat conduction coefficient of the battery cell bracket 16 is greater than or equal to 0.7 W / m-K, and at the second temperature, the heat conduction coefficient of the battery cell bracket 16 is less than or equal to 0.02 W / m-K. Or at the first temperature, the heat conduction coefficient of the battery cell bracket 16 is greater than or equal to 0.8 W / m-K, and at the second temperature, the heat conduction coefficient of the battery cell bracket 16 is less than or equal to 0.015 W / m-K.

[0065] It should be noted that during the use of the battery pack 100, there may be a risk of thermal runaway as charging or discharging continues. After thermal runaway occurs, the battery pack 100 may experience dangerous safety accidents such as explosion or fire. If the battery pack 100 on the outdoor wheeled tool 200 undergoes thermal runaway, it is also a major safety accident for the tool itself. If the position of the battery compartment 24 is designed to be relatively close to the seat 25, it is very likely to harm the user.

[0066] To reduce the harm after the thermal runaway of the battery pack 100, the battery pack 100 can also include a pressure relief device 14, which can discharge the hot air inside the battery pack 100 or block the leakage of open flames when the battery pack 100 undergoes thermal runaway, preventing the battery pack 100 from exploding or preventing the battery pack 100 from further damaging the battery compartment 24 or other structures.

[0067] In one embodiment, refer to Figure 4 , Figure 5 and Figures 12 to 14, 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 layer of metal mesh 142. The pressure relief device 14 can be detachably installed at the installation opening 11c on the housing 11 by means of screws or plugging, etc., or can be fixedly installed on the housing 11 by other means.

[0068] Reference Figures 12 to 14 , the metal mesh 142 is arranged inside the waterproof and breathable layer 141. When the air pressure inside the housing 11 of the battery pack 100 is basically balanced with the outside 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 thermal runaway occurs in the battery pack 100, the thermal runaway cell unit 121 may quickly discharge hot air, and the air pressure inside 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 inside the battery pack 100 is greater than the outside air pressure, it will cause the pressure relief device 14 to deform. For example, it will cause the pressure relief device 14 to bulge from the inside to the outside, or at least cause the waterproof and breathable layer 141 to bulge outwards. When the air pressure inside 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 inside the battery pack 100 is released to the outside of the battery pack 100. It can be understood that when the metal mesh 142 is arranged inside the waterproof and breathable layer 141 and an open flame appears during thermal runaway of the battery pack 100, the metal mesh 142 can block the open flame inside the battery pack 100 to a certain extent.

[0069] In one embodiment, the waterproof and 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.

[0070] In one embodiment, the waterproof and breathable layer 141 is provided with pre-pressed marks 1411 as Figure 13 and Figure 14 shown. The thickness of the film at the pre-pressed marks 1411 is less than that at other positions, so it is easier to rupture. In one embodiment, the shape of the pre-pressed marks 1411 can be "*" shape, or "+" shape or any other shape.

[0071] In one embodiment, the waterproof and breathable layer 141 can be a layer of waterproof and breathable membrane, or can be a waterproof and breathable valve, or an aluminum-plastic membrane, etc.

[0072] In one embodiment, the metal mesh 142 may include a first metal mesh 1421 and a second metal mesh 1422 arranged adjacent to each other. The first metal mesh 1421 is disposed inside the second metal mesh 1422. The mesh holes of the two metal meshes do not coincide at least partially, thereby increasing the mesh density of the metal mesh 142 and enhancing the ability of the metal mesh 142 to block open flames.

[0073] In one embodiment, the pressure relief device 14 is disposed at the bottom housing of the battery pack 100, or on the side or other positions. In one embodiment, a plurality of pressure relief devices 14 may be provided on the battery pack 100. The plurality of pressure relief devices 14 may be disposed on the same surface of the battery pack 100, or on different surfaces.

[0074] In one embodiment, the pressure relief device 14 further includes a protection bracket 143. The protection bracket 143 is detachably mounted on the sub-housing 11. The waterproof breathable layer 141 and the metal mesh 142 are detachably mounted to the protection bracket 143, or are non-detachably mounted on the protection bracket 143. In one embodiment, the hardness of the protection bracket 143 is less than or equal to the hardness of the housing 11.

[0075] In one embodiment, the pressure relief device 14 further includes a stabbing needle 144. The stabbing needle 144 is disposed outside the waterproof breathable layer 141. After the waterproof breathable layer 141 bulges outward to a certain extent, it can contact the stabbing needle 144, and the stabbing 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 inside the battery pack 100 after the battery pack 100 undergoes thermal runaway. In one embodiment, the stabbing needle 144 may be a conical protrusion with a pointed head facing the waterproof breathable layer 141. In one embodiment, the stabbing needle 144 may be formed by the protection bracket 143.

[0076] 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 when the user moves the battery pack 100, the waterproof breathable layer 141 may also be accidentally broken. To prevent the pressure relief device 14 from being triggered before the battery pack 100 undergoes thermal runaway, the battery pack 100 is further provided with a protection structure 145. The protection structure 145 is disposed outside the waterproof breathable layer 141. In one embodiment, the protection structure 145 is detachably mounted outside the protection bracket 143, or detachably mounted on the housing 11, or integrally formed with the protection bracket 143, or mounted inside the protection bracket 143, etc. In one embodiment, the protection structure 145 may be Figure 14The fence structure shown. In one implementation, when the battery pack 100 is not installed on the outdoor wheeled tool 200, the protection structure 145 is installed on the battery pack 100. When it is necessary to install the battery pack 100 on the outdoor wheeled tool 200 to supply power to the tool, the protection structure 145 can be detached from the battery pack 100 to avoid affecting the triggering of the pressure relief device 14.

[0077] In the above embodiment, the pressure relief device 14 provided on the battery pack housing can be used as a heat dissipation device for the battery pack 100 when the battery pack 100 does not have a thermal runaway problem, dissipating heat from the battery pack. When the battery pack has a thermal runaway, it can quickly discharge the hot air or smoke inside the battery pack 100, and at the same time prevent open flames from leaking out, thereby avoiding more serious safety accidents.

[0078] Reference Figure 15 and Figure 16 , the battery pack 100 may further include an energy conversion device 15 disposed in the housing 11 and in thermal communication with the plurality of battery cell units 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 inside the battery pack 100 into kinetic energy, thereby playing a role in discharging the hot air inside the battery pack. As Figure 15 and Figure 16 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 disposed at the corner of the accommodation space formed by the housing 11. If the battery pack 100 has a thermal runaway, the hot air inside the battery pack 100 can drive the fan to rotate, and under the action of centrifugal force, it is discharged circumferentially from the fan blades of the fan 15. In one embodiment, the housing 11 is provided with at least one air outlet, and the air outlet partially or entirely corresponds to the air outlet of the fan 15. In one embodiment, a flow guiding member 151 is further disposed in the housing 11, which can guide the airflow discharged from the fan 15 to be discharged toward the pressure relief port 112 of the housing 11.

[0079] 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.

[0080] In the above embodiment, by providing the energy conversion device 15 inside the battery pack 100, the thermal energy during the thermal runaway of the battery pack can be converted into kinetic energy and discharged.

[0081] Reference Figure 15 , a plurality of avoidance holes 125 are reserved on the battery cell bracket 16 that supports or fixes the battery cell unit 121 for the fixing member 122 to pass through, so as to fix two adjacent battery cell modules 12 together.

[0082] As can be seen from the above embodiments, the temperature rise of the battery cell unit 121 substantially at the geometric center of the battery cell module 12 is faster and higher, which to a certain extent makes the temperature difference between different battery cell units 121 in the battery cell module 12 larger, and thermal runaway is more likely to occur.

[0083] To solve the above problems, the avoidance holes 125 can be staggeredly distributed at multiple positions of the battery cell module 12. As Figure 15 shown, taking the polar end face 126 of the battery cell module 12 as the positive end face, the positive end face is divided into multiple divided areas 1201 by the dividing lines A and B. The avoidance holes 125 can be arranged in each divided area 1201 or at the junction of the divided areas 1201, i.e., on the dividing lines A and B, or at the intersection of the dividing lines. The divided area 1201 is an area with substantially the same shape, area or size formed by the dividing lines A and B. In one embodiment, the avoidance holes 125 are substantially located at the geometric center of each divided area 1201, or at the intersection of the dividing lines. In one embodiment, assuming that the distance between the avoidance hole 125 and the edge of the battery cell module 12 is r1, then r1 is greater than 0. In one embodiment, there are no other avoidance holes 125 within the range of r2 from any avoidance hole 125, where r2 is greater than r1. That is to say, by arranging the avoidance holes 125 substantially at the geometric center position of the battery cell module 12 or at the geometric center of each divided area 1201 divided, the mutual distance between the battery cell units 121 near the above positions is increased to a certain extent, and the heating degree of the battery cell units 121 substantially near the above positions can be reduced. Among them, the battery cell units 121 near the above positions can be understood as the battery cell units 121 within a preset range from the avoidance hole 125, or the surrounding battery cell units 121 adjacent to the avoidance hole 125.

[0084] By setting the positions of the avoidance holes 125 in the above manner, the heating degree of the battery cell units 121 in the middle area of the battery cell module 12 or the middle area of the divided area 1201 can be reduced, the temperature difference between the battery cell units 121 in the battery cell module 12 can be reduced, and the consistency of the battery cell units 121 can be ensured.

[0085] Refer to Figure 17a and Figure 17b, the battery pack 100 at least includes 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 a first compartment 11a and a second compartment 11b. Among them, heat insulation is provided between the first compartment 11a and the second compartment 11b. In this embodiment, the housing 11 can form the first compartment 11a and the second compartment 11b. In one embodiment, the first compartment 11a and the second compartment 11b can be two independent inner housings that are arranged separately from the housing 11 inside the housing 11 and are thermally insulated from each other. The so-called heat insulation can be understood as that heat transfer cannot or hardly occurs between the two compartments. In this way, after a thermal runaway occurs in one battery cell module, it will not affect the other battery cell module or have a relatively small impact on the other battery cell module. It can be understood that the first battery cell module 12a and the second battery cell module 12b are connected in parallel. That is to say, after one battery cell module fails, the other battery cell module can still support charging and discharging.

[0086] In one embodiment, the thermal conductivity of the housing materials of the first compartment 11a and the second compartment 11b at room temperature is greater than or equal to 25 W / m·K, or greater than or equal to 30 W / m·K, or greater than or equal to 35 W / m·K, or greater than or equal to 40 W / m·K. Exemplarily, in one embodiment, the yield strength of the housing materials of the first compartment 11a and the second compartment 11b is greater than or equal to 150 Mpa, or greater than or equal to 160 Mpa, or greater than or equal to 170 Mpa, or greater than or equal to 180 Mpa, or greater than or equal to 190 Mpa, etc. In one embodiment, the housing materials of the first compartment 11a and the second compartment 11b can include at least one of PV6 or flame-retardant nylon.

[0087] Exemplarily, as Figure 17b shown, the first compartment 11a can be provided or formed with a first pressure relief port 11a1, and the second compartment 11b can 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. Among them, the first pressure relief port 11a1 can be used as a port of the first pressure relief channel 11a2, that is, the first inlet, and the second pressure relief port 11b1 can be used as a port of the second pressure relief channel 11b2, that is, the second inlet. A pressure relief valve 111 is formed on the housing 11, and the pressure relief valve 111 can be the outlet of the first pressure relief channel 11a2 and the outlet of the second pressure relief channel 11b2. That is to say, 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 can be understood that when there are multiple compartments in the battery pack 100, the multiple compartments can also respectively connect their respective pressure relief channels to the pressure relief valve 111 of the housing 11 to achieve the effect of discharging the hot air or smoke in the compartments.

[0088] In this embodiment, the first pressure relief channel 11a2 can be an air flow channel of any shape formed by the inward depression of the first partition chamber 11a, or a hollow air flow channel formed by the body of the first partition chamber 11a itself. It can be understood that the formation method of the second pressure relief channel 11b2 and the first pressure relief channel 11a2, or the shape of the pressure relief channel, etc. can be the same or different.

[0089] In one embodiment, in order to increase the flow time of the hot air in the pressure relief channel 11a2, the first pressure relief channel 11a2 and the second pressure relief channel 11b2 can be designed as curved channels, or a buffer structure such as a buffer protrusion or a buffer sheet can be added in the channel.

[0090] In one embodiment, the risk of thermal runaway of the battery pack can also be reduced by electronic components. Refer to Figure 18 a circuit structure 1000 in the battery pack 100 shown, which at least includes a discharge resistor 101, a plurality of switching elements 102, a parameter detection unit 103, and a controller 104. Among them, each switching element 102 is respectively electrically connected to a plurality of battery cell units 121 and the discharge resistor 101. 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 there is a risk of thermal runaway of the battery pack according to the battery parameters, and control at least one switching element 102 to conduct when it is determined that the battery pack 100 has a risk of thermal runaway, so that the battery cell unit 121 electrically connected thereto can discharge through the discharge resistor 101.

[0091] In this embodiment, the parameter detection unit 103 can at least detect the temperature of the battery cell unit 121, or the ambient temperature in the battery pack 100, or the air pressure in the battery pack 100, etc. The controller 104 can determine that the battery pack 100 has a risk of thermal runaway when the battery parameters are greater than or equal to the parameter threshold. For example, when the temperature in the battery pack 100 is greater than the temperature threshold, it is determined that the battery pack 100 has a risk of thermal runaway. After the controller 104 determines that the battery pack 100 has a risk of thermal runaway, it can select at least one battery cell unit 121 to discharge through the discharge resistor 101 according to the power or temperature of the battery cell unit 121. For example, it can select the battery cell unit 121 with the highest power to discharge, or select the battery cell unit 121 with a high temperature to discharge, or select the battery cell unit 121 to discharge after comprehensively considering the temperature and power. In this embodiment, two or more battery cell units 121 can be connected in parallel to discharge through the discharge resistor 101.

[0092] During the process of discharging the battery cell unit 121 through the discharge resistor 101, the controller 104 can detect the remaining power of the discharging battery cell unit, and when the remaining power is less than or equal to the power threshold, control the switching element 102 to disconnect, so that the resistor stops discharging. Generally, the above-mentioned power threshold is less than or equal to 50% of the total power of the battery cell unit.

[0093] In this embodiment, the discharge resistor 101 can be disposed between the housing 11 and the plurality of battery cell units 121, or disposed close to the housing 11, so as to better transfer heat through the discharge resistor 101.

[0094] It can be understood that after the battery pack 100 is installed on the outdoor wheeled tool 200, if thermal runaway occurs on the tool, there are also certain safety hazards to the tool itself. Therefore, in order to avoid or minimize the harm of the thermal runaway of the battery pack 100 to the outdoor wheeled tool 200, as Figure 19 shown, an air flow channel 241 is provided or formed on the battery compartment 24 of the outdoor wheeled tool 200. A pressure relief port 112 is formed on the housing 11 of the battery pack 100, and the pressure relief port 112 of the battery pack 100 is communicated with one end of the air flow channel 241 on the battery compartment 24, and the other end of the air flow channel 241 is communicated with 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 air flow channel 241 on the battery compartment 24. Among them, the pressure relief port 112 on the battery pack 100 may be the same as or different from the pressure relief valve 111 on the battery pack 100 in the above embodiment, and no specific limitation is made here.

[0095] In this embodiment, at least one battery pack 200 can be accommodated in the battery compartment 24, and at least one air flow channel 241 is provided in the battery compartment 24.

[0096] In one embodiment, the air flow 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 air flow channel 241 is basically the wall thickness of the battery compartment 24.

[0097] In one embodiment, the air flow channel 241 is a channel having a certain normal length and an air inlet and an air outlet. As Figure 19As shown, a fireproof cover 242 is further provided outside the battery compartment 24. 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 air flow 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 the air inlet of the air flow 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 the air outlet of the air flow channel 241. In this embodiment, the fireproof cover 242 can be fixedly installed on the battery compartment 24 or detachably installed on the battery compartment 24.

[0098] In one embodiment, the air flow channel 241 can also be a channel formed by the hollow of the wall of the battery compartment 24 itself.

[0099] To increase the flow time of the hot air in the air flow channel 241, a buffer structure can be provided in the air flow channel 241, such as buffer protrusions or buffer sheets, etc. Or the air flow channel 241 can be set as a curved channel.

[0100] In one embodiment, a fireproof structure can also be provided in the air flow channel 241. For example, a metal mesh can be set as the fireproof structure to prevent the open fire after the thermal runaway of the battery pack 100 from escaping outside the battery compartment 24.

[0101] In one embodiment, the air flow channel 241 formed by the battery compartment 24 can at least lead the hot air after the thermal runaway of the battery pack 100 to the bottom of the battery compartment 24 for discharge. As Figure 20 and Figure 21 shown, a plurality of openings 2431 can be provided on the bottom plate 243 at the bottom of the battery compartment 24, and the openings 2431 can release the air flow to the outside atmosphere. In this embodiment, the openings 2431 on the bottom plate 243 can be understood as the air flow channel 241, and the thickness of the bottom plate 243 can be understood as the channel length of the air flow channel 241. By providing a plurality of openings 2431 on the bottom plate 243, the hot air released by the battery pack 100 can be diverted 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.

[0102] In one embodiment, at least the bottom plate 243 of the non-sealed compartment can be recessed outward to form a groove 2432. For example, Figure 21 as shown, a rectangular groove 2432 is recessed outward basically at the middle position 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.

[0103] Continue to refer to Figure 20, at least one smoke exhaust channel 244 can 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 discharged, so that the gas or smoke in the battery compartment 24 can quickly converge to the opening 2431 at the bottom plate 243 of the compartment and be discharged outside the battery compartment 24. In one embodiment, the slot on the side wall or the top cover of the battery compartment 24 can be used as the smoke exhaust channel 244.

[0104] In this embodiment, at least one compartment wall of the battery compartment 24 is a mesh structure, or at least one side wall surface of the battery compartment 24 is a mesh structure. Exemplarily, the compartment wall of the mesh structure can be a metal mesh, a rigid plastic mesh or a mesh of other materials.

[0105] In this embodiment, the main material of the battery compartment 24 can be an iron-based alloy, or can be a nickel-based alloy, a cobalt-based alloy, a copper-based alloy, etc.

[0106] 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.

[0107] Continue to refer to Figure 20 , the battery compartment 24 can include at least two sub-compartments, and a partition 240 is provided between at least two adjacent sub-compartments. At least part of the partition 240 is made of a fire retardant 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 can be the same as or at least partially the same as the main material of the battery compartment 24 or different from the main material of the battery compartment 24.

[0108] In one embodiment, the thermal conductivity of the fire retardant material forming 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.

[0109] 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, so as to obtain various data combinations of thermal runaway. In one embodiment, the battery management module can detect the battery data in real time and compare it with the thermal runaway data combination to determine whether the battery pack has occurred or is about to occur thermal runaway, and then control the outdoor wheeled tool to enter the shutdown state, or control the tool to give an alarm prompt, such as beeping alarm or displaying alarm information on the display screen. In this embodiment, the battery management module can be set in the battery pack 100, or can be set in the outdoor wheeled tool 200, or can be set in both.

[0110] In another embodiment, the pressure relief device 14 can at least guide the high-temperature gas generated during thermal runaway of at least one battery cell unit 121 out of the housing 11. Alternatively, the pressure relief device 14 can at least prevent the open flame generated during thermal runaway of at least one battery cell unit 121 from escaping outside the housing 11. Or the pressure relief device 14 can block the open flame generated during thermal runaway of at least one battery cell unit 121 from escaping outside the housing 11 and at least guide the high-temperature gas generated during thermal runaway of at least one battery cell unit 121 out of the housing 11. It should be noted that the high-temperature gas can include high-temperature smoke or dust or air. In this embodiment, at least the pressure relief device 14 can form a gas communication path between the inside and outside of the housing 11, that is to say, the inside and outside of the housing 11 can form gas communication through the pressure relief device 14.

[0111] Reference Figure 22 , the pressure relief device 14 can be installed at the installation opening 11c of the housing 11 by means of screws or snap connection, etc. Reference Figure 23 , the pressure relief device 14 and the housing 11 are connected by a plurality of screws 11d.

[0112] In one implementation, the surface of the housing 11 forming the installation opening 11c is substantially flush with the outer surface of the installed pressure relief device 14, or the surface of the housing 11 forming the installation opening 11c is higher than the outer surface of the installed pressure relief device 14. Thus, during storage or use of the battery pack 100, since the outer surface of the pressure relief device 14 protrudes from the surface of the housing 11, the pressure relief device 14 is prevented from bearing the weight of the entire battery pack 100, causing damage or accidental triggering of the pressure relief device 14. In other embodiments, the surface of the housing 11 of the installation opening 11c can also be lower than the outer surface of the installed pressure relief device 14.

[0113] In one implementation, the pressure relief device 14 can be installed at the bottom end of the battery pack 100, or installed on the side of the battery pack 100, etc. In principle, the pressure relief device 14 is arranged at one end of the battery pack 100 away from the user. For example, in the riding mower 200a, the bottom end of the mower 200a faces the ground and is far from the operator or the users around the body, and the bottom end of the battery pack 100 faces the ground after the battery pack 100 is installed in the battery compartment 24. Therefore, the pressure relief device 14 can be arranged at the bottom end of the battery pack 100, so that when the battery pack 100 in the riding mower 200a undergoes thermal runaway, the high-temperature gas ejected from the battery pack 100 will face the ground and will not cause injury to people. In other implementation manners, 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 the electric tool to which it is applied, and is not limited herein.

[0114] In some embodiments, multiple pressure relief devices 14 may be installed on the battery pack 100. The locations or quantities of pressure relief devices 14 installed on battery packs of different types or for different purposes may be different, and are not limited here.

[0115] This embodiment is described by taking the pressure relief device 14 installed at the bottom of the battery pack 100 as an example. Figures 22 to 27 The direction marked in the table shall prevail. Figures 23 to 27 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 assembly 41 and a guide assembly 40. When thermal runaway occurs in one or more battery cell units 121 in the battery module 12, open flames or high-temperature gases can be generated instantly or in a short period of time in the accommodation space formed by the shell 11. 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 not only partially impact the shell 11, but most of it will impact the pressure relief device 14. The fire-blocking assembly 41 of the pressure relief device 14 can at least prevent the open flame from escaping, while the guide assembly 40 can slow down the flow rate of the gas or reduce the temperature of the escaping gas.

[0116] Continue to refer Figures 23 to 27 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.

[0117] The partition 411 may be a metal mesh and / or metal foam with a plurality of fire-blocking holes 4111. In one embodiment, the partition 411 may be at least two adjacent layers of 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 25 to 27 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 fireproof space between the two layers of metal meshes. Figure 22 As shown, the opening of the mounting opening 11c is shaped like a Chinese character "U." The "opening" inside the "U" shape can be understood as an effective opening, i.e., a through-opening in the housing 11, while the opening outside the "U" shape can be used to accommodate the guide assembly 40. In this embodiment, the effective opening of the mounting opening 11c can at least expose all the fire-blocking holes 4111 in the partition mesh 411, thereby maximizing the function of the fire-blocking assembly 41.

[0118] In this embodiment, the thickness of a layer of separator net 411, or a layer of metal mesh, or a layer of metal foam is greater than or equal to 1 mm. For example, it can be 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.

[0119] In this embodiment, the separator net 411 can also be a plastic with a super-high thermal conductivity, or graphite, or graphene, or a CVD diamond film, etc. In some embodiments, the separator net 411 can also have at least a metal coating or a plastic organic coating.

[0120] In this embodiment, the separator net 411 can also be referred to as a metal mesh or a metal separator net or a metal foam. In one implementation, as Figure 28 shown, a phase change coating 412 is provided on the outer side of at least one layer of metal mesh, or the side facing away from the battery cell module 12. When the high-temperature open fire inside the housing 11 touches 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 assist the metal mesh in blocking the open fire. In one implementation, the phase change coating 412 can be a wax layer. The material of the phase change coating in this embodiment is not limited, and other materials that can vaporize when encountering high-temperature open fire can also be used as the material of the phase change coating 412.

[0121] In one embodiment, as Figure 29 shown, a fire extinguishing material 413 can also be provided between two adjacent metal meshes. The fire extinguishing material 413 can be a material with high flame retardancy or fire extinguishing properties. For example, it can be a perfluorinated hexanone patch or a high-resistance fuel, etc., which can assist the metal mesh in blocking the open fire.

[0122] It should be noted that the above embodiments can be used alone or in combination, and are not limited here.

[0123] Referring to Figure 26 and Figure 27 , the separator 43 provided at the upper end of the guiding component 40 and the lower end of the separator net 411 can be a layer of waterproof and breathable membrane, or an aluminum-plastic membrane, etc., which can isolate water vapor, dust and other impurities under normal conditions. The separator 43 has a certain elasticity and can bulge from the inside to the outside when the air pressure inside the housing 11 is greater than the air pressure outside the housing 11. Thus, after the battery pack 100 undergoes thermal runaway, the separator 43 bulges outwards. As the bulge continues to increase, the separator 43 ruptures, so that the gas passing through the separator net 411 can break through the separator 43 and enter the guiding component 40.

[0124] As Figure 26As shown, a channel inlet 4031 is provided at the upper end of the guiding component 40 to allow the gas that escapes through the diaphragm 43 to enter the guiding component 40. In this embodiment, the one facing the inner side of the battery pack 100, or the one close to the fireproof component 41, or the one adjacent to the fireproof component 41 serves as the first guiding member 401, and the one opposite to the first guiding member 401 is the second guiding member 402. Refer to Figure 23 , the screw 11d penetrates through the fireproof component 41, the housing 11, and the first guiding member 401 and then is driven into the second guiding member 402, thereby fixing the pressure relief device 14 on the housing 11. To prevent the gas from escaping through the gap between the contact surfaces of the pressure relief device 14 and the housing 11 instead of being discharged along the Figure 24 shown air flow path 4033, a sealing member 42 is provided between the guiding component 40 and the housing 11, which can seal the gap between the guiding component 40 and the housing 11. In fact, as Figure 26 shown, the sealing member 42 is arranged at the upper end of the first guiding member 401, or arranged in the groove 40a formed by the first guiding member 401, and the height of the sealing member 42 is greater than or equal to the depth of the groove 40a.

[0125] Refer to Figures 23 to 27 , a first guiding rib 4011 is provided on the end surface of the first guiding member 401 opposite to the second guiding member 402, or rather, the first guiding rib 4011 is provided on the lower end surface of the first guiding member 401; a second guiding rib 4021 is provided on the end surface of the second guiding member 402 opposite to the first guiding member 401, or rather, the second guiding rib 4021 is provided on the upper end surface of the second guiding member 402. Among them, the first guiding rib 4011 and the second guiding rib 4021 can define or form a plurality of guiding channels 403 in the guiding component 40. The channel inlets 4031 of the plurality of guiding channels 403 are arranged on the first guiding member 401, for example, at the position of the first guiding member 401 facing the diaphragm 43. The circumferential gap formed by the cooperation of the first guiding member 401 and the second guiding member 402 can serve as the channel outlet 4032. Refer to Figure 26 and Figure 27 , the first guiding rib 4011 and the second guiding rib 4021 can be spiral ribs, so that the guiding channels 403 formed by the cooperation of the first guiding rib 4011 and the second guiding rib 4021 can be a plurality of spiral air flow channels. In other embodiments, the first guiding rib 4011 and the second guiding rib 4021 can also be other shaped continuous or discontinuous ribs.

[0126] Refer to Figure 24The 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 can 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 flow out from the channel outlet 4032, thereby forming Figure 24 The bold line indicates the wavy or curved airflow path 4033. In this embodiment, by selecting or configuring airflow paths 4033 of various shapes, the contact area between the guide assembly 40 and the high-temperature gas can be ensured to be sufficiently large, thereby effectively slowing down the airflow velocity and further preventing the leakage of open flames.

[0127] In this embodiment, the guide assembly 40 can be made of metal or other materials with good thermal conductivity or heat absorption properties and have a certain mechanical strength. In one implementation, when the guide assembly 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 assembly 40 can also be plastic with ultra-high thermal conductivity, or graphite, or graphene, or CVD diamond film, etc. In some embodiments, the guide assembly 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. It should be noted that the thermal conductivity coefficients of the guide assembly 40 vary when made of different materials, and the thermal conductivity coefficients of different materials are not listed here.

[0128] In this embodiment, if Figure 24 As shown, a needle 4022 is provided on the second guide member 401 in the same direction as the second guide rib 4021. Figure 13 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 gas.

[0129] refer to Figure 30 A protective member 114 is further provided on the bottom shell 11 of the battery pack 100, and the protective member 114 covers at least the channel outlet 4032 of the guide channel 403.Figure 30 As shown by the thick solid line in the figure, a communication channel 1141 communicating with the outside is formed between the protective member 114 and the lower housing of the battery pack 100. One end of the communication channel 1141 is the channel outlet 4032 of the guiding channel 403, and the other end of the communication channel 1141 communicates with the outside. The communication channel 1141 and the guiding channel 403, or rather the air flow path 4033, can also be used as the path for the battery pack 100 to discharge the high-temperature and high-pressure gas during thermal runaway. In this embodiment, by providing the protective member 114 that at least covers the channel outlet 4032 of the guiding channel 403, it is possible to avoid damage to the pressure relief device 14 due to the drop or collision of the battery pack 100, and it is also possible to prevent mud and water from blocking the channel outlet 4032, thereby affecting the discharge of high-temperature and high-pressure gas or open fire by the pressure relief device 14. In one embodiment, the housing 11 can be recessed inward to form the communication channel 1141 between the housing 11 and the protective member 114, or at least one groove is formed inside the protective member 114 as the communication channel 1141.

[0130] In this embodiment, the protective member 114 can be a plastic part or a metal part with a certain stiffness. A protective coating can be provided on the inner side of the protective member 114. The protective coating can be composed of a flame-retardant material, a high-temperature-resistant material, a phase-change material, or the like.

[0131] In one implementation, as Figure 30 shown, the protective member 114 covers or surrounds the pressure relief device 14 and the bottom housing of the battery pack 100. That is to say, at least the lower surface of the pressure relief device 14 is located in the space between the lower end surface of the housing 11 and the protective member 114, and the pressure relief device 14 is not directly exposed to the external environment. In one implementation, the protective member 114 can also be disposed at least around the pressure relief device 14 at the lower end of the housing 11, and an avoidance portion is provided on the protective member 114 to avoid the second guiding member 402 of the pressure relief device 14, at least exposing the second guiding member 402 to the external environment. In this implementation, the protective member 114 and the second guiding member 402 are substantially on the same horizontal plane, or at least the second guiding member 402 of the pressure relief device 14 does not protrude from the protective member 114.

[0132] In this embodiment, the housing 11 has a high strength, a large thickness, or is wrapped with a rubber layer, which can prevent the battery pack 100 from being damaged when it drops. However, if the positive and negative electrodes of the battery cell unit 121 in the battery pack 100 are facing the housing 11, since the first end cap 162 and the second end cap 163 are semi-closed end caps, after the battery cell unit 121 undergoes thermal runaway, it is very easy to conduct to the housing 11 corresponding to the positive or negative electrode of the battery cell unit 121, or conduct to the adjacent battery cell unit 121 through the semi-closed end cap.

[0133] To avoid this situation, the battery pack 100 further includes an exhaust housing 17. AsFigure 31 As shown, the exhaust housing 17 is disposed on two polar end faces of the battery cell module 12. That is to say, two exhaust housings 17 can be provided in the battery pack 100 having one battery cell module 12. Or it can be understood that the exhaust housing 17 is provided on the polar end face formed by the positive electrode arrangement of the battery cell support 16 and the battery cell unit 121, and the exhaust housing 17 is also provided on the polar end face formed by the negative electrode arrangement of the battery cell support 16 and the battery cell unit 121.

[0134] As Figure 32 , a plurality of first battery cell units 121a extending in a direction perpendicular to the first plane are provided in the first plane, and a plurality of second battery cell units 121b extending in a direction perpendicular to the second plane are provided in the second plane. The first battery cell support 16a supports the first battery cell units 121a, and the second battery cell support 16b supports the second battery cell units 121b. Among them, the first battery cell units 121a and the first battery cell support 16a constitute the first battery cell module 12a, and the second battery cell units 121b and the second battery cell support 16b constitute the second battery cell module 12b. Among them, the positive electrode of the first battery cell unit 121a corresponds to the positive electrode of the second battery cell unit 121b, or the negative electrode of the first battery cell unit 121a corresponds to the positive electrode of the second battery cell unit 121b, or the negative electrode of the first battery cell unit 121a corresponds to the negative electrode of the second battery cell unit 121b, or the positive electrode of the first battery cell unit 121a corresponds to the negative electrode of the second battery cell unit 121b. A certain distance is provided between the corresponding first battery cell unit 121a and the second battery cell unit 121b. The exhaust housing 17 can be provided in this interval. That is to say, the exhaust housing 17 is provided between the first battery cell module 12a and the second battery cell module 12b. In this embodiment, the exhaust housing 17 is also adjacently provided on the other end face of the first battery cell module 12a away from the second battery cell module 12b, and the exhaust housing 17 is also adjacently provided on the other end face of the second battery cell module 12b away from the first battery cell module 12a. That is to say, three exhaust housings 17 can be provided in the battery pack 100 including two battery cell modules 12.

[0135] In one embodiment, the number of the exhaust housings 17 in the battery pack 100 is greater than the number of the battery cell modules 12. For example, the number of the exhaust housings 17 is one more than the number of the battery cell modules 12.

[0136] In this embodiment, the material properties, density, thermal conductivity, heat distortion temperature, etc. of the exhaust housing 17 are the same as or substantially the same as those of the battery cell support 16, which will not be elaborated here.

[0137] As Figure 32 and Figure 33 shown, the exhaust housing 17 forms at least one exhaust passage 171. Among them, Figure 10This is a diagram that directly shows the internal structure of the exhaust housing 17 after removing the end face with the intake part 1711. The extending direction of the exhaust passage 171 is substantially perpendicular to the extending direction of the battery cell unit 121. The exhaust passage 171 can be a curved passage, and the curved shape can be consistent with the curved shape in the cross-section formed after the battery cell units 121 are arranged in the battery cell support 16, so as to make the structure of the battery pack 100 more compact. In one embodiment, baffles 173 are provided between adjacent exhaust passages 171.

[0138] The exhaust passage 171 includes an intake part 1711 and an air outlet 1712. The intake part 1711 corresponds to the positive or negative electrode of the battery cell unit 121, and the air outlet 1712 can correspond to a window (not shown) on the housing 11. In this embodiment, an intake part 1711 is provided on an end face adjacent to the battery cell support 16 of the exhaust housing 17, and the positive or negative electrode of each battery cell unit 121 corresponds to an intake part 1711. The number of intake parts 1711 on each exhaust housing 17 is the same as the number of battery cell units 121, Figure 31 and Figure 32 only one intake part 1711 is shown in the figure, and the other intake parts 1711 are not shown. The air outlet 1712 can be provided on any one or more of the four peripheries of the exhaust housing 17, and the air outlet 1712 can be closed or semi-closed, Figure 31 and Figure 32 the air outlet 1712 shown in the figure corresponds to one or both ends of each exhaust passage 171. In one embodiment, the air outlet 1712 on the exhaust housing 17 located between two battery cell modules 12 can be provided at the end of the exhaust passage 171, that is, on the side surface of the exhaust housing 17. In one embodiment, the air outlet 1712 can also be provided on the other end face of the exhaust housing 17 opposite to the end face provided with the intake part 1711. In one embodiment, the air outlet 1712 can also be called an explosion-proof valve, and can be detachably installed on the exhaust housing 17 as a standard part, or can be integrally formed with the exhaust housing 17.

[0139] In this embodiment, as Figure 32 shown, the curved baffle 173 forms a curved exhaust passage 171 on the outside, and the intake part 1711 basically corresponds to each turning point of the curved exhaust passage 171. Therefore, the adjacent intake parts 1711 are basically blocked by the curved part of the exhaust passage 171, forming a kind of misalignment design. This misalignment design can effectively prevent the high-temperature gas ejected by the battery cell unit 121 that has thermal runaway from directly impacting the surrounding battery cell units 121, and does not affect the exhaust effect.

[0140] When a large amount of hot gas is generated due to thermal runaway of the battery cell unit 121, the hot gas can enter the exhaust passage 171 through the intake part 1711, thereby preventing the battery cell unit 121 in thermal runaway from damaging the battery cell unit 121 inside after piercing through the battery cell accommodation cavity 164. It can be understood that the hot gas can gradually cool down in the exhaust passage 171 or be discharged outside the battery pack 100 through the air outlet 1712.

[0141] In one embodiment, the intake part 1711 is in a closed state at the first temperature and is opened at the second temperature, where the second temperature is greater than the first temperature.

[0142] In one embodiment, the intake part 1711 of the exhaust passage 171 can be integrally formed with the exhaust housing 17, that is, the intake part 1711 does not have a substantial opening or gap for other substances to enter the exhaust passage 171. In this embodiment, the thickness of the housing at the intake part 1711 is less than the thickness at other positions of the exhaust housing 17, for example, it can be 0.25 times or 0.5 times or 0.3 times the thickness of the housing at other positions, etc. Thus, when thermal runaway occurs in the battery cell unit 121, a large amount of hot gas can break through the weak housing at the intake part 1711 and enter the exhaust passage 171.

[0143] In one embodiment, the intake part 1711 of the exhaust passage 171 can include a stop part 172, and the stop part 172 has a stop state and an open state. When the impact strength is less than the set value, the stop part 172 is in the stop state, and when the impact strength is greater than the set value, the stop part 172 is in the open state. In one embodiment, the stop part 172 can be an exhaust valve, and the valve is closed when the impact strength is less than the set value and opened when the impact strength is greater than the set value. In one embodiment, as Figure 34 shown, the stop part 172 can be a stop housing formed by the exhaust housing 17, and a plurality of through holes 174 are provided around the stop part 172. Due to the existence of the through holes 174, the strength of the exhaust housing 17 between adjacent through holes 174 is reduced, and when thermal runaway occurs in the battery cell unit 121, the exhaust housing 17 between adjacent through holes 174 is easily broken. In some embodiments, the intake part 1711 can also be a through hole of any shape, for example, it can be a round hole.

[0144] In another embodiment, the exhaust housing 17 can be composed of a first exhaust housing 17a and a second exhaust housing 17b as Figures 35a to 36 shown. Among them, a baffle 173 is provided on the inner end face of the second exhaust housing 17b opposite to the first exhaust housing 17a. After the first exhaust housing 17a is covered on the second exhaust housing 17b to form the exhaust housing 17, the first exhaust housing 17a can abut against the baffle 173, so that an exhaust passage 171 can be formed between adjacent baffles 173. AsFigure 36 and Figure 37 As shown, after the first exhaust housing 17a and the second exhaust housing 17b are covered, there is a certain gap between the inner side of the side wall 17a1 of the first exhaust housing 17a and the outer side of the side wall 17b1 of the second exhaust housing 17b, and this gap can be used as the air outlet 1712 of the pressure relief channel 171. In this embodiment, the second exhaust housing 17b can also be used as the battery cell support 16 to support the battery cell unit 121, such as Figure 35a and Figure 35b As shown, a baffle 173 is formed or installed on the left side of the second exhaust housing 17b, which can form the exhaust channel 171, and the battery cell unit 121 is supported on the right side of the second exhaust housing 17b. In this embodiment, as Figure 35b As shown, an independent sleeve 160 is sleeved on each battery cell unit 121, and two adjacent battery cell supports 16 can keep the sleeve 160 in a fixed position within the battery cell module 12.

[0145] In one embodiment, the battery pack 100 further includes an insulating layer 167, as Figure 35a As shown, the insulating layer 167 is a thin layer that can fit inside the second exhaust housing 17b and is basically similar in shape to the second exhaust housing 17b. For example, the insulating layer 167 is fitted inside each exhaust channel 171. When a thermal runaway occurs in the battery cell unit 121, the high-temperature and high-pressure gas or open flame can break through the insulating layer 167 after passing through the intake part 1711, and can spray out from the end of the battery cell unit 121 into the exhaust channel 171, while other battery cell units 121 can be protected by other intact insulating layers 167, so that more heat will not spread to other battery cell units 121 that have not experienced thermal runaway. In this embodiment, the insulating layer 167 can be an insulating spray layer, or insulating paper, or mica paper, or mica sheet, etc. In one embodiment, an insulating layer 167 can be provided inside each exhaust housing 17 in the battery pack 100. In one embodiment, if there is a In one embodiment, at least one side of the exhaust channel 171 is fitted with the insulating layer 167. In one embodiment, an insulating layer 167 can be provided at one end of the inner side of the exhaust housing 17 close to the battery cell module 12, and the insulating layer 167 can be fitted on the battery cell connection piece 166. The high-temperature gas or open flame generated by the thermal runaway of the battery cell unit 121 can break through the insulating layer 167 and enter the exhaust housing 17, and can be discharged along the exhaust channel 171.

[0146] In this embodiment, after the battery cell unit 121 undergoes thermal runaway, the generated flame or gas can be discharged from the outlet 1712 along the pressure relief channel 171. Since the exhaust channels 1712 of the exhaust casings 17 on both end faces of the battery cell module 12 are opposite, if the high-temperature gas or open flame after the thermal runaway of the battery cell unit 121 is discharged from the air outlet 1712 too fast, it may enter the other exhaust channel 171 along the air outlet 1712 on the other side, thus affecting the other end face of the battery cell unit 121. In this embodiment, a partition 18 with at least one bend is provided at the air outlet 1712 of the pressure relief channel 171 to change the discharge direction of the flame or gas coming out of the air outlet 1712, and can prevent the flame from directly spraying on the battery cell casing of the battery cell unit 121. As Figure 31 shown in the exhaust direction in (the arrows in the figure indicate the exhaust direction), the direction of the gas or open flame discharged from the air outlet 1712 is opposite to the discharge direction of the gas after being changed by the partition 18. The bent portion of the partition 18 can block the flow rate of the flame or air flow, preventing the flame or air flow from spraying too fast.

[0147] In this embodiment, the partition 18 can be fixed on the side wall 17b1 of the second exhaust casing 17b, for example, it can be fixed by means of adhesives or screws. In one embodiment, the partition 18 can be formed by the second exhaust casing 17b, that is to say, the side wall 17b1 of the second exhaust casing 17b can be provided with a bend to surround the side wall 17a1 of the first exhaust casing 17a, so as to extend the exhaust path of the exhaust port 1712.

[0148] In one embodiment, as Figures 38 to 40 shown, in order to increase the reliability of the electrical connection between two battery cell modules 12, a connection component 123 can be used to connect two adjacent battery cell modules 12. In one implementation, the connection component 123 can include a metal sheet, a metal row or a metal bar, and the metal sheet, the metal row or the metal bar can be respectively fixed on the two battery cell modules 12 by screws. In one implementation, the metal sheet, the metal row or the metal bar can also be fixed on the two battery cell modules 12 by welding. For example, it can be welded by means of laser welding and / or ultrasonic welding. In this embodiment, the metal sheet, the metal row or the metal bar can be copper, copper alloy or other types of metals. A bus bar 124 can be used to connect at least two battery cell modules 12 in series or in parallel. In this embodiment, the connection component 123 can penetrate through the bus bar 124 and then fix the battery cell module 12.

[0149] In one embodiment, as Figure 40As shown, at least one or a layer of thermal insulation 19 may be provided between two adjacent battery cell modules 12 to prevent high-temperature gas or open flame generated after thermal runaway of one battery cell module 12 from spraying to the adjacent battery cell module 12. In other embodiments, thermal insulation 19 may be provided on both end faces of a battery cell module 12. Alternatively, the thermal insulation 19 may be provided between the exhaust shell 17 and the polar end face of the battery cell module 12. Alternatively, the thermal insulation 19 may be provided inside the exhaust shell 17, for example, attached to at least one of the two inner side faces of the exhaust shell 17 corresponding to the polar end face. Alternatively, at least part of the shell of the exhaust shell 17 may serve as the thermal insulation 19, that is, at least one surface of the exhaust shell 17 itself may serve as the thermal insulation 19, for example, at least one of the two side faces of the exhaust shell 17 corresponding to the polar end face is provided as the thermal insulation 19.

[0150] In this embodiment, the thermal insulator 19 can be an aluminum alloy plate or a thin metal plate composed of its components, or a metal plate or plastic plate composed of other highly insulating materials, or a thermal insulation coating or filler composed of highly insulating materials such as aerogel. In one embodiment, the thermal insulator 19 can be a heat spreader, a metal plate, a thermally conductive plastic plate, or a composite of these, or a plate coated with a phase-change endothermic material. This coated endothermic material has a high phase transition temperature of at least 80°C. When the high-temperature, high-pressure airflow or flame generated by thermal runaway strikes the thermal insulator 19, the phase-change material changes state, removing and transferring heat. In one implementation, the phase-change endothermic material can be a similar material such as phase-change wax. In one embodiment, the thermal insulator 19 can also be a mica plate. In one embodiment, the thermal insulator 19 can be attached between a cell module 12a and the exhaust housing 17, or between a cell module 12b and the exhaust housing 17, where the exhaust housing 17 is the exhaust housing between the two cell modules 12a and 12b. In other embodiments, the exhaust housing 17 may not be provided between two adjacent battery cell modules 12, but a heat insulating member 19 may be placed between the two adjacent battery cell modules 12 to prevent cross-spraying.

[0151] In other embodiments, a phase change material may be coated on the inner and / or outer sides of the end caps at both ends of the battery cell unit 121, i.e., the first end cap 162 and the second end cap 163, or the inner and / or outer sides of the exhaust housing 17, or the inner side of the housing 11, or at least the inner side of the barrel 1101, or the inner side of the bottom housing of the battery pack 100. The phase change material may also be phase change paraffin or a material with similar properties. In this embodiment, the critical value of the phase change temperature of the phase change material is at least about 10°C higher than the maximum temperature when the various components in the battery pack 100 are operating normally or at least without thermal runaway.

[0152] In one embodiment, the battery cell unit 121 is a two-way valve battery cell. That is to say, safety relief valves are respectively arranged at both the positive and negative ends of the battery cell unit 121. When thermal runaway occurs in the battery cell unit 121, high-temperature and high-pressure gas or open fire can be ejected from both end faces, ensuring that the high-temperature and high-heat gas or open fire can enter the exhaust housing 17 arranged at both ends of the battery module 12 and be discharged through the exhaust housing 17.

[0153] In one embodiment, as Figures 38 to 40 shown, the edge parts of the first bracket 168 and the second bracket 169 are connected with basically no gap. It can be understood that a battery cell bracket 16 is supported on each of the two end faces of a battery module 12, and there is basically no gap at the edge connection of the two battery cell brackets 16. In this embodiment, except for the parts supported by the battery cell brackets 16 at both ends, no partition or baffle is arranged in the middle part of each battery cell unit 121. That is to say, the middle part of the battery cell unit 121 is exposed to the air environment surrounded by the two battery cell brackets 16. For example Figure 39 and Figure 40 shown, the length L1 of the outer side 1683 surface of the first bracket 168 in the first direction C is greater than the length L2 of the support part 1684 on its inner side for supporting the end of the battery cell unit 121. The shape of the second bracket 169 is basically the same as that of the first bracket 168. The length of the outer side of the second bracket 169 in the first direction C can be defined as L3, and the length of the support part of the second bracket 169 for supporting the end of the battery cell unit 121 is L4. After the first bracket 168 and the second bracket 169 fix the battery cell unit 121 inside them, the middle part of the battery cell unit 121 is exposed to the air environment surrounded by the two battery cell brackets 16. It can be understood that the sum of the lengths of L1 and L2 is basically equal to or greater than the length of the battery cell unit 121 to prevent the battery cell unit 121 from being exposed outside the battery cell bracket 16.

[0154] Due to the low thermal conductivity of air, it is difficult to conduct heat. When thermal runaway occurs in the battery cell unit 121, most of the heat or open fire can be discharged outside the battery module 12 through the exhaust channel 171. And because the edges of the two battery cell brackets 16, that is, the first bracket 168 and the second bracket 169, are basically seamlessly connected, the battery cell unit 121 can be completely wrapped in the accommodation space formed by the battery cell brackets 16. Therefore, the gas or open fire generated by the thermal runaway of one battery cell unit 121 has little or no impact on the battery cell unit 121 itself. In this embodiment, the first bracket 168 and the cover plate 1681 covering the outside of the first bracket 168 can form the exhaust housing 17, or the second bracket 169 and the cover plate 1691 covering the outside of the second bracket 169 can form the exhaust housing 17. That is to say, an exhaust channel 171 can be provided on the side of the first bracket 168 or the second bracket 169 that does not fix the end of the battery cell unit 121.

[0155] In one embodiment, the battery module 12 can be fixed to the housing 11 to enhance its stability within the battery pack 100. In this embodiment, Figure 41 The shown battery pack 100 includes two battery modules 12a and 12b, and a plurality of fixing members 122 that can penetrate at least two battery modules 12. In other embodiments, after penetrating the battery module 12, the fixing member 122 can fix the battery module 12 to the side of the barrel 1101 or to the reinforcing member 1103. Thus, to a certain extent, the fixing member 122 can bear the gravity of the battery module 12 to reduce the force-bearing degree of the battery cell bracket 16 or the exhaust housing 17. When an external force acts on the side of the barrel 1101, the force can be borne by the side of the barrel 1101 or the reinforcing member 1103, and the battery module 12, or rather the battery cell unit 121, does not bear the force. In one embodiment, the fixing member 122 can be a screw. It can be understood that on the basis of penetrating the battery module 12, the fixing member 122 can also penetrate the exhaust housing 17 or the heat insulation layer 19.

[0156] As Figure 41 shown, the battery cell bracket 16 supporting each battery module 12 can be composed of two parts, the first bracket 168 and the second bracket 169. The first bracket 168 and the second bracket 169 can be fixed together by a buckle or a fixing member 122 (for example, a screw), and the battery cell unit 121 is fixed between the first bracket 168 and the second bracket 169. In this embodiment, after the two battery cell brackets 16 are fixed together, they can form independent cavities for accommodating the battery cell units 121. That is to say, the battery cell units 121 can be separated from each other by the battery cell brackets 16.

[0157] In one embodiment, referring to Figures 42 to 44In a battery cell module 12 shown, a first bracket 168 and a second bracket 169 respectively support two ends of a battery cell unit 121, and a sleeve bracket 170 is arranged between the first bracket 168 and the second bracket 169. Refer to Figure 43 , the sleeve bracket 170 is integrally formed and has a side enclosure and a plurality of sleeves 1701 that are independent and connected and surrounded by the side enclosure. The plurality of sleeves 1701 can be connected together by ribs. To ensure the wrapping strength between battery cell units 121 and the convenience of assembly. Refer to Figure 44 , it is defined that in the second direction D, the length of the supporting portion of the first bracket 168 supporting the battery cell unit 121 is L5, the length of the sleeve bracket 170 is L6, and the length of the supporting portion of the second bracket 169 supporting the other end of the battery cell unit 121 is L7. Among them, the sum of L5, L6, and L7 is less than the length of the battery cell unit 121 in the second direction D, that is, less than the axial length of the battery cell unit 121. There is a gap L8 between the first bracket 168 and the sleeve 170 in the second direction D, and a gap L9 between the sleeve bracket 170 and the second bracket 169. That is to say, the battery cell unit 121 can be intermittently wrapped by the first bracket 168, the sleeve bracket 170, and the second bracket 169 in the longitudinal direction. Thus, the problem of uneven heat transfer between battery cell units 121 can be solved, so that the heat generated when any battery cell unit 121 undergoes thermal runaway can be evenly transferred to other battery cell units 121.

[0158] This embodiment does not introduce in detail the battery cell connection pieces 166, the insulating layers 167, and the cover plates 1681 and 1691 attached to both sides of the first bracket 168 and the second bracket 169. For details, reference can be made to the descriptions in other embodiments.

[0159] In one embodiment, refer to Figures 45 to 47 , the battery cell module 12 shown includes a plurality of battery cell units 121, a first bracket 168 and a second bracket 169 that support both ends of the battery cell units 121, and also includes an intermediate bracket 180 sleeved on at least part of the battery cell units 121. In this embodiment, the intermediate bracket 180 is arranged between the first bracket 168 and the second bracket 169 to improve the heat dissipation effect and heat balance of the battery cell units 121.

[0160] In this embodiment, the intermediate bracket 180 includes a plurality of accommodating portions 1801. The shapes, sizes, wall thicknesses, or heights of some of the accommodating portions are different, so that the contact areas between different accommodating portions 1801 and the battery cell units 121 are different. For example, some of the accommodating portions 1801 can accommodate multiple battery cell units 121, and some can accommodate one battery cell unit 121. That is to say, the number of the accommodating portions 1801 in this embodiment is less than or equal to the number of the battery cell units 121. By providing the accommodating portions 1801 with differences, the contact areas between the battery cell units 121 at different positions and the intermediate bracket 180 can be adjusted, thereby improving the temperature consistency problem of the battery cell units 121 in the whole package. In one embodiment, the intermediate bracket 180 further includes a heat dissipation portion 1802, and the heat dissipation portion 1802 may include a plurality of heat dissipation fins to increase the heat dissipation area.

[0161] Reference Figure 45 , at the junction between a plurality of support points 1692 at the end of the battery cell unit 121 supported by the second bracket 169, a support column 1693 is formed. The support column 1693 may be a solid columnar structure, or may be a hollow columnar structure to reduce the weight of the battery cell bracket 16.

[0162] In some embodiments, a high-temperature and high-pressure insulation coating may be provided on the inner side of at least one side surface of the housing 11, thereby increasing the high-temperature resistance of the housing 11 and preventing the housing 11 from being burned through when the battery cell unit 121 undergoes thermal runaway, so that open flames leak out. Alternatively, a metal plate, such as an aluminum plate, may be added to the inner layer of at least one side surface of the housing 11, which can also prevent the housing 11 from being burned through due to thermal runaway. Or in other embodiments, at least one side surface of the housing 11 may be provided as a metal shell.

[0163] In one embodiment, a fireproof layer may also be added inside the battery compartment 24, such as a fireproof blanket, or an aerogel coating, or a heat-insulating metal or plastic such as mica flakes.

[0164] It should be noted that different embodiments in this embodiment can be combined with each other to obtain better or more excellent results.

[0165] It should be noted that, for the convenience of understanding the same or similar components in different embodiments, the present application sets the reference numerals of the same or similar components in different embodiments to be the same, but it does not mean that the components with the same reference numerals are exactly the same components. For example, Figure 39 the first bracket 168 in Figure 42 and the first bracket 168 in

[0166] The basic principles, main features, and advantages of the present application have been shown and described above. Those skilled in the art should understand that the above embodiments do not limit the present application in any form. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. An electric tool, comprising: A tool body; A battery pack mounting part, arranged on the tool body for mounting at least one battery pack; The battery pack includes: A housing; At least two battery cell modules, each battery cell module including a plurality of battery cells, the converging surfaces of the positive electrodes and the converging surfaces of the negative electrodes of the battery cells being two polar end faces of the battery cell module; A heat insulation member, arranged at least between the polar end faces of two adjacent battery cell modules.

2. The power tool according to claim 1, characterized in that, The heat insulation member is arranged on the two polar end faces of the battery cell module.

3. The power tool according to claim 1, characterized in that, The battery pack further includes an exhaust housing, arranged on at least one of the polar end faces of the battery cell module; the heat insulation member is arranged between the polar end face of the battery cell module and the exhaust housing.

4. The power tool according to claim 3, characterized in that, The heat insulation member is arranged inside the exhaust housing.

5. The power tool according to claim 3, characterized in that, At least part of the housing of the exhaust housing forms the heat insulation member.

6. The power tool according to any one of claims 1 to 5, characterized in that, The heat insulation member includes at least one of a metal plate, a thermally conductive plastic plate, a composite plate, a plate coated with a heat insulation material, a plate coated with a phase change material, or a mica plate.

7. The power tool according to claim 1, characterized in that The battery pack further includes a reinforcing member; the reinforcing member is arranged on the inner side surface and / or the outer side surface of the housing opposite to the polar end face.

8. The power tool according to claim 7, wherein, The reinforcing member is fixed to the housing.

9. The power tool according to claim 7, wherein, The reinforcing member is embedded in the housing.

10. The power tool according to claim 1, characterized in that, At least part of the inner side and / or the outer side of the housing is provided with at least one layer of flame retardant coating.

11. The electric tool according to claim 1, characterized in that The battery pack further includes a fixing member; the fixing member is arranged to pass through at least two battery cell modules and then fix the battery cell modules to the housing.

12. The power tool according to claim 1, characterized in that, At least one layer of flame retardant wrapping layer 1211 is arranged on the outer layer of at least one battery cell.

13. A battery pack, comprising: A housing; At least two battery cell modules, each battery cell module including a plurality of battery cells, the converging surfaces of the positive electrodes and the converging surfaces of the negative electrodes of the battery cells being two polar end faces of the battery cell module; A heat insulation member, arranged at least between the polar end faces of two adjacent battery cell modules.

14. The battery pack according to claim 13, characterized in that, The heat insulation member is further arranged on any one of the polar end faces of the battery cell module.

15. A battery pack, comprising: A housing; A battery cell module, including a plurality of battery cells, the battery cell module being arranged inside the housing; A pressure relief device, detachably mounted to the housing; The pressure relief device is arranged to at least guide the high-temperature gas generated by thermal runaway of at least one battery cell out of the housing; Wherein, the pressure relief device is formed with a guiding channel for guiding the high-temperature gas; The battery pack further includes: A protective member, at least covering the channel outlet of the guiding channel and forming a communication channel for communicating the channel outlet with the outside.

16. The battery pack according to claim 15, characterized in that, The protective member is mounted to the housing and completely covers the pressure relief device.

17. The battery pack according to claim 15, wherein, On the battery pack, the pressure relief device does not protrude from the protective member.

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