Batteries and power-consuming devices

Abstract

An embodiment of the present application provides a battery and a power consumption device. The battery includes a battery cell and a protective member. The battery cell includes a pressure reducing mechanism. The protective member includes a protective area facing the pressure reducing mechanism in a thickness direction of the pressure reducing mechanism, and the protective area is used to block at least a part of the material released from the battery cell through the pressure reducing mechanism. The weight energy density of the battery cell is E, and the minimum distance between the pressure reducing mechanism and the protective area in the thickness direction is L. E and L satisfy 2Wh / (kg·mm)≦E / L≦7010Wh / (kg·mm). On the premise of meeting the requirements for battery safety protection, the embodiment of the present application reduces the design redundancy of the distance between the protective member and the pressure reducing mechanism, reduces the loss of the energy density of the battery, and improves the safety of the battery.

Description

[Technical Field]

[0001] This application relates to the field of battery technology, and more particularly to batteries and power consuming devices. [Background technology]

[0002] With the continuous progress of battery technology, various new energy industries using batteries as energy storage devices are developing rapidly. In the development of battery technology, in addition to improving battery performance, safety issues are also an issue that cannot be ignored. If the safety issues of a battery cannot be guaranteed, the battery cannot be used. How to improve battery safety is a technical issue in battery technology that needs to be solved as soon as possible. Summary of the Invention

[0003] The present application provides a battery and a power consuming device whose safety can be improved.

[0004] According to a first aspect, an embodiment of the present application provides a battery including a battery cell and a protective member. The battery cell includes a pressure reduction mechanism. The protective member includes a protective area facing the pressure reduction mechanism in a thickness direction of the pressure reduction mechanism, and the protective area is used to block at least some of the substances released from the battery cell through the pressure reduction mechanism. The weight energy density of the battery cell is E, and the minimum distance between the pressure reduction mechanism and the protective area in the thickness direction is L. E and L satisfy the relationship 2Wh / (kg·mm)≦E / L≦7010Wh / (kg·mm).

[0005] Generally, when a battery cell experiences thermal runaway, the larger the value of E, the more intense the chain reaction that occurs inside the battery cell and the higher the temperature and rate at which materials are released from the battery cell. Therefore, the larger the value of E, the higher the minimum distance L between the pressure reducing mechanism and the protective area. If E is large and L is small, particulate matter in the high-temperature, high-velocity materials is likely to accumulate on the thermal runaway battery cell and spread onto the normal battery cells, even bouncing back onto them. This not only poses a risk of burning or damaging the normal battery cells, but also increases the temperature of the normal battery cells, putting them at risk of thermal runaway and posing a safety risk. If E is small and L is large, the distance between the pressure reducing mechanism and the protective area is overdesigned, reducing the space utilization rate inside the battery and wasting the battery's energy density. The above technical solution limits the value of E / L to 2Wh / (kg·mm)~7010Wh / (kg·mm), thereby reducing the redundancy in the design of the distance between the protective member and the pressure reducing mechanism, reducing the loss of the battery energy density, and improving the safety of the battery, while still meeting the requirements for battery safety protection.

[0006] In some embodiments, E and L satisfy 10 Wh / (kg·mm)≦E / L≦800 Wh / (kg·mm).

[0007] In some embodiments, the value of E is between 100Wh / kg and 3505Wh / kg. If the weight energy density of the battery cell is 100Wh / kg or more, the energy density of the battery can be effectively improved, thereby improving the range of the power-consuming device that uses the battery. If the weight energy density of the battery cell is 3505Wh / kg or less, a thermal runaway battery cell can be brought into a controllable state, thereby reducing safety risks.

[0008] In some embodiments, the value of E is between 100 Wh / kg and 400 Wh / kg.

[0009] In some embodiments, the value of L is between 0.5 mm and 50 mm.

[0010] The above technical solution limits the value of L to 0.5mm to 50mm, thereby reducing the redundancy in the design of the distance between the protective member and the pressure reducing mechanism, reducing the loss of battery energy density, and improving battery safety, while still meeting the requirements for battery safety protection.

[0011] In some embodiments, the value of L is between 0.5 mm and 10 mm.

[0012] In some embodiments, the protective member has a flow path for the heat exchange medium to flow therethrough, and the protective member can simultaneously perform a protective function and a thermal management function, thereby simplifying the structure of the battery and improving the energy density of the battery.

[0013] In some embodiments, the protective member further includes a heat exchange area, the battery cell further includes a first wall, and the pressure reduction mechanism is provided in the first wall. The heat exchange area is connected to the first wall and thereby exchanges heat with the first wall. By exchanging heat with the first wall, the heat exchange area adjusts the temperature of the battery cell, allowing the battery cell to operate within an appropriate temperature range and improving the cycle characteristics of the battery cell.

[0014] In some embodiments, the battery further includes a thermally conductive structure, at least a portion of which is located between the first wall and the heat exchange area and connects the first wall and the heat exchange area. The thermally conductive structure can connect the first wall and the heat exchange area, thereby stabilizing heat exchange between the first wall and the heat exchange area. The thermally conductive structure can further support the protective member, thereby spacing the protective member from the pressure reducing mechanism.

[0015] In some embodiments, the battery cell further includes a first wall, and the pressure reducing mechanism is provided on the first wall. The protective member includes a main body and a support, the main body being spaced apart from the first wall along the thickness direction, and the support is located between the first wall and the main body and used to connect the first wall and the main body. The main body includes a protective region.

[0016] In the above technical solution, the support part not only fixes the main body part to the battery cell, but also separates the protective area from the pressure reducing mechanism, and the minimum distance between the pressure reducing mechanism and the protective area can be adjusted by adjusting the size of the support part.

[0017] In some embodiments, the protective member is a flat plate structure, which is easy to mold and install.

[0018] In some embodiments, the battery cells are multiple, and the protective member is located on the same side of the pressure reduction mechanisms of the multiple battery cells. The protective member includes multiple protective regions, and the multiple protective regions correspond one-to-one to the pressure reduction mechanisms of the multiple battery cells.

[0019] In the above technical solution, the protective member can cover the pressure reduction mechanisms of multiple battery cells, and no matter which battery cell experiences thermal runaway, the protective member can block high-temperature and high-velocity materials, thereby reducing safety risks.

[0020] In some embodiments, the battery further includes a housing, and the battery cell and the protective member are housed in the housing. The protective member is fixed to a surface of the housing facing the vacuum mechanism.

[0021] In the above technical solution, the protective member can block substances released from the battery cells, thereby reducing the thermal shock received by the casing and reducing the amount of heat transferred to the casing, thereby reducing the risk of the casing melting and being penetrated, thereby improving the safety of the battery. The casing can fix the protective member, thereby reducing the risk of the protective member moving due to the impact of high-temperature and high-velocity substances, reducing the probability of the protective member being hit and damaged, and reducing the risk of the protective member losing its protective function.

[0022] In some embodiments, the battery cell includes a first wall, a second wall, and a third wall, the pressure reducing mechanism is provided in the first wall, the second wall is located on a side of the first wall away from the protective member, and the third wall connects the first wall and the second wall, and the battery cell further includes an electrode terminal, the electrode terminal being disposed on at least one of the first wall, the second wall, and the third wall.

[0023] In some embodiments, the material of the protective member comprises at least one of an inorganic salt, an inorganic ceramic, an elemental metal, elemental carbon, and an organic colloid.

[0024] According to a second aspect, an embodiment of the present application provides a power consuming device including a battery according to any embodiment of the first aspect for supplying electrical energy. [Brief explanation of the drawings]

[0025] In order to more clearly describe the technical solutions in the embodiments of the present application, the following briefly describes the drawings required for the embodiments of the present application. It should be understood that the drawings shown below are only some embodiments of the present application, and those skilled in the art can further obtain other drawings based on the drawings without any creative efforts.

[0026] [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Figure 2] 1 is an exploded schematic view of a battery according to some embodiments of the present application. [Figure 3] 1 is a structural schematic diagram of a battery according to some embodiments of the present application. [Figure 4] 4 is another structural schematic diagram of the battery shown in FIG. 3, where the pressure reduction mechanism of the battery cell of the battery is in an operating state. [Figure 5] 4 is an enlarged schematic view of a circled portion A of the battery shown in FIG. 3. FIG. [Figure 6] 1 is a structural schematic diagram of a battery cell of a battery according to some embodiments of the present application. [Figure 7] 1 is a structural schematic diagram of a battery according to some embodiments of the present application. [Figure 8]FIG. 2 is a structural schematic diagram of a battery according to another embodiment of the present application. [Figure 9] FIG. 2 is a structural schematic diagram of a battery according to another embodiment of the present application. [Figure 10] FIG. 2 is a structural schematic diagram of a battery according to another embodiment of the present application. [Figure 11] 1 is a schematic diagram of a testing process for a battery according to some embodiments of the present application.

[0027] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION OF THE INVENTION

[0028] In order to clarify the objectives, technical solutions and advantages of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative efforts fall within the scope of protection of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terms used in the specification of the present application are intended merely to describe specific embodiments and are not intended to limit the present application. The terms "comprise" and "have" and their equivalents in the specification and claims of the present application and the description of the drawings are intended to be non-exclusive. The terms "first," "second," etc. in the specification and claims of the present application or the drawings are used to distinguish between different objects and are not used to describe a particular order or hierarchy.

[0030] References herein to an "embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. Appearances of the term "embodiment" in various places in this specification do not necessarily all refer to the same embodiment, nor do they refer to embodiments that are mutually exclusive, independent, or alternative to other embodiments.

[0031] It should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "attach," "connected," "connection," and "attachment" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection. They may be directly connected, indirectly connected via an intermediate medium, or internal communication between two elements. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0032] The term "and / or" in this application merely describes the relationship between related objects and indicates that three types of relationships can exist. For example, A and / or B can indicate three situations: A exists alone, A and B exist simultaneously, and B exists alone. In this application, the symbol " / " generally indicates that the related objects before and after it are in an "or" relationship.

[0033] In the embodiments of the present application, the same reference numerals indicate the same elements, and detailed descriptions of the same elements will be omitted in different embodiments for the sake of brevity. Note that the dimensions such as thickness, length, and width of each element in the embodiments of the present application and the overall dimensions such as thickness, length, and width of the integrated device shown in the drawings are merely illustrative and do not limit the present application in any way.

[0034] The term "plurality" as used herein refers to two or more (including two).

[0035] The term "parallel" in this application not only includes cases where something is absolutely parallel, but also includes situations where it is generally recognized in engineering as being approximately parallel, and at the same time, the term "perpendicular" not only includes cases where something is absolutely perpendicular, but also includes situations where it is generally recognized in engineering as being approximately perpendicular.

[0036] In the present application, the battery cells may include, but are not limited to, lithium-ion battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells. The battery cells may be cylindrical, flat, rectangular, or have other shapes, but are not limited to these. The battery cells may be hard-case battery cells, soft-pack battery cells, or other types of battery cells.

[0037] A battery cell includes an electrode assembly and an electrolyte. Exemplarily, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell operates primarily through the transfer of metal ions between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector includes a positive electrode current collector and a positive electrode tab. The positive electrode active material layer is coated on the positive electrode current collector, and the positive electrode tab is not coated with the positive electrode active material layer. For example, in a lithium-ion battery cell, the positive electrode current collector may be made of aluminum, and the positive electrode active material layer includes a positive electrode active material. The positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, a ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer being coated on the surface of the negative electrode current collector, the negative electrode current collector including a negative electrode current collector portion and a negative electrode tab, the negative electrode active material layer being coated on the negative electrode current collector portion, and the negative electrode tab not being coated with the negative electrode active material layer. The negative electrode current collector may be made of copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon, etc. The separator may be made of PP (polypropylene), PE (polyethylene), etc.

[0038] The battery referred to in the embodiments of this application refers to a single physical module containing one or more battery cells to provide higher voltage and capacity. A battery generally includes a housing for packaging one or more battery cells. The housing can prevent liquids or other foreign objects from affecting the charging and discharging of the battery cells.

[0039] The development of battery technology requires simultaneous consideration of various design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge efficiency, as well as battery safety.

[0040] The pressure reduction mechanism in a battery cell has a significant impact on battery safety. For example, if a short circuit or overcharging occurs, thermal runaway can occur inside the battery cell, causing a sudden increase in pressure. In such cases, activating the pressure reduction mechanism can release the internal pressure to the outside, preventing the battery cell from exploding or catching fire.

[0041] The pressure reduction mechanism may be an element or member that is activated when the battery cell reaches a certain condition. For example, the pressure reduction mechanism may be an element or member that is activated when the internal pressure or internal temperature of the battery cell reaches a predetermined threshold to release the internal pressure and / or internal substances. The design of the threshold varies depending on design requirements. The threshold may depend on one or more materials of the positive electrode sheet, the negative electrode sheet, the electrolyte, and the separator in the battery cell.

[0042] The pressure reducing mechanism may be, for example, an explosion-proof valve, an air valve, a pressure reducing valve, or a safety valve. Specifically, the pressure reducing mechanism may be a pressure-sensitive element or structure, i.e., when the internal pressure of the battery cell reaches a predetermined threshold, the pressure reducing mechanism is activated or a weak area within the pressure reducing mechanism ruptures to form a pressure reducing path for releasing the internal pressure. Alternatively, the pressure reducing mechanism may be a temperature-sensitive element or structure, i.e., when the internal temperature of the battery cell reaches a predetermined threshold, the pressure reducing mechanism is activated to form a pressure reducing path for releasing the internal pressure. Alternatively, the pressure reducing mechanism may be an actively operable member, for example, the pressure reducing mechanism may be activated upon receiving a battery control signal.

[0043] Other forms of the pressure reduction mechanism may be used. For example, the pressure reduction mechanism may be a weak structure on the outer case of the battery cell, and when the battery cell experiences thermal runaway, the weak structure cracks or deforms to form a pressure reduction path for releasing the internal pressure. For example, the pressure reduction mechanism may be a weld on the outer case of the battery cell.

[0044] "Activation" as referred to in this application means that the pressure reduction mechanism generates an action or is activated to a certain state, thereby releasing the internal pressure and / or internal material of the battery cell. The action generated by the pressure reduction mechanism includes, but is not limited to, at least a portion of the pressure reduction mechanism rupturing, crushing, tearing, or opening. When the pressure reduction mechanism is activated, high-temperature, high-velocity material inside the battery cell is discharged as a discharged product from the activated location. In this manner, pressure can be released from the battery cell under controllable pressure conditions, preventing the occurrence of potentially more serious accidents.

[0045] The emissions from battery cells referred to in this application include, but are not limited to, electrolyte, dissolved or split positive and negative electrode sheets, separator fragments, high-temperature and high-velocity gases produced by reactions, flames, etc.

[0046] When a battery cell experiences thermal runaway, the battery cell releases waste into the housing. The housing is also provided with a pressure reduction mechanism, and when the pressure reduction mechanism of the housing is activated, the waste is discharged outside the housing at a set position.

[0047] The inventors have noted that the effluents emitted from the battery cells are at high temperature and high velocity, and the impact of the effluents can cause the battery to explode, leading to fire outside the battery and posing a safety risk.

[0048] After discovering the above problem, the inventors attempted to install a protective member at a position opposite the pressure reduction mechanism of the battery cell. The protective member can block high-temperature, high-velocity substances released from the battery cell and can withstand the impact of high-temperature, high-velocity substances, thereby reducing the risk of the battery exploding and improving safety.

[0049] The inventors discovered through their research that particulate matter in high-temperature, high-velocity materials bounces off or scatters around when blocked by a protective member. If the distance between the pressure reducing mechanism and the protective member is too small, the particulate matter may accumulate on the battery cell and spread to other components (e.g., healthy battery cells adjacent to the thermal runaway battery cell), potentially bouncing off the other components, increasing the risk of damaging those components and posing a safety risk. To reduce the safety risk, the inventors attempted to increase the distance between the pressure reducing mechanism and the protective member, but increasing the distance reduces the space utilization rate within the battery and the battery's energy density. Designing the distance between the pressure reducing mechanism and the protective member too far results in wasted energy density. Through further research, the inventors discovered that when a battery cell experiences thermal runaway, the weight energy density of the battery cell is related to the temperature and velocity of the material being released from the battery cell. The higher the weight energy density of the battery cell, the more likely it is that particulate matter in high-temperature, high-velocity materials will accumulate and destroy other components adjacent to the thermal runaway battery cell.

[0050] In view of this, the inventors provide a technical solution to set the distance between the pressure reducing mechanism and the protective member based on the weight energy density of the battery cell, thereby reducing safety risks and reducing the waste of the battery's energy density.

[0051] The technical solutions described in the embodiments of the present application are applied to power-consuming devices that use batteries.

[0052] The power consuming devices may be vehicles, mobile phones, mobile devices, laptops, ships, spacecraft, electric toys, power tools, etc. The vehicles may be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles, and the new energy vehicles may be pure electric vehicles, hybrid vehicles, range-extender vehicles, etc. The spacecraft include aircraft, rockets, space shuttles, spaceships, etc. The electric toys include stationary or mobile electric toys such as game consoles, electric car toys, electric ship toys, and electric aircraft toys. The power tools include metal cutting power tools, polishing power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drivers, concrete vibrators, and electric planers. The embodiments of the present application are not particularly limited to the above power consuming devices.

[0053] For convenience of explanation, the following embodiment will be described using a vehicle as an example of a power consuming device.

[0054] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application.

[0055] 1, a battery 2 is installed inside the vehicle 1, and the battery 2 may be installed at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to supply power to the vehicle 1, and can be used, for example, as an operating power source for the vehicle 1.

[0056] The vehicle 1 may further include a controller 3 and a motor 4, where the controller 3 is used to control the battery 2 to supply power to the motor 4, for example, to meet the operating power needs of the vehicle 1 for starting, navigation, and driving.

[0057] In some embodiments of the present application, the battery 2 can provide driving power to the vehicle 1 not only as an operating power source for the vehicle 1 but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas.

[0058] FIG. 2 is an exploded schematic view of a battery according to some embodiments of the present application.

[0059] As shown in FIG. 2, the battery 2 includes a housing 20 and battery cells 10 , and the battery cells 10 are housed in the housing 20 .

[0060] The housing 20 is used to house the battery cells 10, and the housing 20 may have various structures. In some embodiments, the housing 20 may include a first housing portion 21 and a second housing portion 22, the first housing portion 21 and the second housing portion 22 being fitted over each other, and the first housing portion 21 and the second housing portion 22 together defining a housing space for housing the battery cells 10.

[0061] In some embodiments, the second housing portion 22 may have a hollow structure with one end open, and the first housing portion 21 may have a plate-like structure, with the first housing portion 21 covering the open side of the second housing portion 22, thereby forming the housing 20 with an accommodation space. In another embodiment, the first housing portion 21 and the second housing portion 22 may both have a hollow structure with one end open, with the open side of the first housing portion 21 covering the open side of the second housing portion 22, thereby forming the housing 20 with an accommodation space.

[0062] The first housing portion 21 and the second housing portion 22 may have various shapes such as a cylinder or a rectangular parallelepiped.

[0063] In order to improve the sealing performance after the first housing part 21 and the second housing part 22 are connected, a sealing member such as a sealant or a seal ring may be installed between the first housing part 21 and the second housing part 22.

[0064] When the first housing part 21 is placed over the top of the second housing part 22, the first housing part 21 can be called an upper housing cover, and the second housing part 22 can be called a lower housing 20.

[0065] The battery 2 may have one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or series-parallel, and a series-parallel connection refers to not only a series connection but also a parallel connection of the multiple battery cells 10. The multiple battery cells 10 can be directly connected in series, parallel, or series-parallel, and then the entire configuration of the multiple battery cells 10 can be housed in a housing 20. Note that the multiple battery cells 10 may first be connected in series, parallel, or series-parallel to form a battery module, and the multiple battery modules may then be further connected in series, parallel, or series-parallel to form an integrated battery module and housed in the housing 20.

[0066] FIG. 3 is a structural schematic diagram of a battery according to some embodiments of the present application; FIG. 4 is another structural schematic diagram of the battery shown in FIG. 3, in which the pressure reduction mechanism of the battery cell is in an operating state; FIG. 5 is an enlarged schematic diagram of a circled portion A of the battery shown in FIG. 3; and FIG. 6 is a structural schematic diagram of a battery cell of the battery according to some embodiments of the present application;

[0067] 3 to 6 , a battery 2 according to an embodiment of the present invention includes a battery cell 10 and a protective member 30. The battery cell 10 includes a pressure reduction mechanism 11. The protective member 30 includes a protective region 31 facing the pressure reduction mechanism 11 in the thickness direction Z of the pressure reduction mechanism 11, and the protective region 31 is used to block at least some of the substances released from the battery cell 10 via the pressure reduction mechanism 11. The weight energy density of the battery cell 10 is E, and the minimum distance between the pressure reduction mechanism 11 and the protective region 31 in the thickness direction Z is L. E and L satisfy the relationship 2Wh / (kg·mm)≦E / L≦7010Wh / (kg·mm).

[0068] There may be one or more battery cells 10. For example, there are multiple battery cells 10. Optionally, the pressure reducing mechanisms 11 of the multiple battery cells 10 all face the protective member 30.

[0069] When the battery cell 10 is in a normal state, the pressure reduction mechanism 11 does not form a pressure reduction path. The pressure reduction mechanism 11 seals the electrode assembly 13 and electrolyte of the battery cell 10 inside the battery cell 10, reducing the risk of electrolyte leakage. When thermal runaway occurs inside the battery cell 10, the pressure reduction mechanism 11 is activated and forms a pressure reduction path 111. Materials inside the battery cell 10 are released to the outside of the battery cell 10 through the pressure reduction path 111.

[0070] The protective member 30 is a component of the battery 2 that withstands the thermal shock of high-temperature, high-velocity substances released from the battery cells 10. Even when subjected to the thermal shock of high-temperature, high-velocity substances released from the battery cells 10, the protective member 30 will not melt, be penetrated, or burst, and will continue to fulfill its protective role.

[0071] The protective member 30 may be a functional member in the battery 2, may only perform the function of thermal protection, or may perform other functions while performing the function of thermal protection. In some examples, the protective member 30 may be a thermal management member in the battery 2, and may not only regulate the temperature of the battery cells 10 but also block high-temperature, high-velocity substances released from the battery cells 10. In another example, the protective member 30 may be part of the outer packaging of the battery 2. In another example, the protective member 30 is an independent member connected to the outer packaging of the battery cells 10 or the battery 2.

[0072] The protection area 31 is a portion of the protection member 30 that overlaps with the decompression mechanism 11 in the thickness direction Z. For example, the projection of the protection area 31 in the thickness direction Z completely overlaps with the projection of the decompression mechanism 11 in the thickness direction Z.

[0073] The protective member 30 may include only the protective region 31, i.e., the entire protective member 30 overlaps with the pressure reduction mechanism 11 in the thickness direction Z, or in addition to the protective region 31, the protective member 30 may include an area that does not overlap with the pressure reduction mechanism 11 in the thickness direction Z.

[0074] The protective member 30 may have one or more protective areas 31. For example, the protective member 30 may have multiple protective areas 31 facing the pressure reducing mechanisms 11 of the multiple battery cells 10, respectively.

[0075] Other members may or may not be present between the protective area 31 and the pressure reduction mechanism 11. For example, a specific member such as an insulating patch for protecting the pressure reduction mechanism 11 of the battery cell 10, a wire harness separator of the battery 2, or other member may be present between the protective area 31 and the pressure reduction mechanism 11. The thermal shock resistance of the protective member 30 is superior to the thermal shock resistance of the member located between the protective area 31 and the pressure reduction mechanism 11, and the member located between the protective area 31 and the pressure reduction mechanism 11 may be penetrated by high-temperature, high-velocity materials released from the battery cell 10.

[0076] The protective member 30 may have a plate-like structure, a frame structure, or other structures. For example, the protective member 30 may be a flat plate with a uniform thickness, or a plate with a non-uniform thickness.

[0077] The protective member 30 may have an integral structure, or may have a structure in which a plurality of sub-members are assembled.

[0078] The protective member 30 may be fixed to the battery cell 10, may be fixed to the housing of the battery 2, or may be fixed to another member of the battery 2, and the embodiment of the present application is not limited thereto.

[0079] The unit of the gravitational energy density E of the battery cell 10 is Wh / kg (watt-hours per kilogram). E=C / G, where C is the capacity of the battery cell 10 and G is the weight of the battery cell 10.

[0080] Generally, when thermal runaway occurs in a battery cell 10, the larger the value of E, the more intense the chain reaction that occurs inside the battery cell 10 and the higher the temperature and rate at which materials are released from the battery cell 10. Therefore, the larger the value of E, the higher the requirement for the minimum distance L between the pressure reducing mechanism 11 and the protected area 31. If E is large and L is small, particulate matter in the high-temperature, high-velocity material is likely to accumulate on the thermally runaway battery cell 10 and spread onto the normal battery cells 10, and then bounce back onto the normal battery cells 10. This not only poses a risk of burning or damaging the normal battery cells 10, but also increases the temperature of the normal battery cells 10, putting them at risk of thermal runaway and posing a safety risk. If E is small and L is large, the distance between the pressure reducing mechanism 11 and the protected area 31 will be overdesigned, reducing the space utilization rate inside the battery 2 and wasting the energy density of the battery 2.

[0081] As a result of the inventors' research, by limiting the value of E / L to 2Wh / (kg·mm) to 7010Wh / (kg·mm), the redundancy in the design of the distance between the protective member 31 and the pressure reducing mechanism 11 is reduced, the loss of energy density of the battery 2 is reduced, and the safety of the battery 2 is improved, while still meeting the requirements for safety protection of the battery 2.

[0082] In some embodiments, the value of E / L is 2 Wh / (kg·mm), 10 Wh / (kg·mm), 50 Wh / (kg·mm), 100 Wh / (kg·mm), 500 Wh / (kg·mm), 800 Wh / (kg·mm), 1000 Wh / (kg·mm), 3000 Wh / (kg·mm), 5000 Wh / (kg·mm), 7000 Wh / (kg·mm), or 7010 Wh / (kg·mm).

[0083] In some embodiments, E and L satisfy 10 Wh / (kg·mm)≦E / L≦800 Wh / (kg·mm).

[0084] In some embodiments, the value of E is between 100 Wh / kg and 3505 Wh / kg.

[0085] If the weight energy density of the battery cell 10 is 100Wh / kg or more, the energy density of the battery 2 can be effectively improved, thereby improving the driving range of the power consumption device that uses the battery 2. If the weight energy density of the battery cell 10 is 3505Wh / kg or less, the battery cell 10 that has gone into thermal runaway can be brought into a controllable state, thereby reducing safety risks.

[0086] Illustratively, the value of E is 100 Wh / kg, 200 Wh / kg, 300 Wh / kg, 400 Wh / kg, 600 Wh / kg, 1000 Wh / kg, 2000 Wh / kg, 3000 Wh / kg or 3505 Wh / kg.

[0087] In some embodiments, the value of E is between 100 Wh / kg and 400 Wh / kg.

[0088] In some embodiments, the value of L is between 0.5 mm and 50 mm.

[0089] If L is too small, particulate matter in the high-temperature, high-velocity material is likely to accumulate on the thermally runaway battery cells 10 and spread onto the normal battery cells 10, and even bounce back onto the normal battery cells 10, which not only poses the risk of burning or damaging the normal battery cells 10 but also increases the temperature of the normal battery cells 10, causing the normal battery cells 10 to experience thermal runaway and posing a safety risk. If L is too large, the distance between the pressure reducing mechanism 11 and the protected area 31 will be over-designed, reducing the space utilization rate inside the battery 2 and resulting in a waste of the energy density of the battery 2.

[0090] In the embodiments of the present application, the value of L is limited to 0.5 mm to 50 mm, thereby reducing the redundancy in the design of the distance between the protective member 31 and the pressure reduction mechanism 11, reducing the loss of energy density of the battery 2, and improving the safety of the battery 2, while still meeting the requirements for safety protection of the battery 2.

[0091] In the embodiment of the present application, the value of L is set to 0.5 mm or more, thereby allowing smooth exhaust in the space between the protective member 30 and the pressure reducing mechanism 11, reducing the risk of insufficient exhaust space causing insufficient exhaust, improving safety and reducing the possibility of battery 2 exploding.

[0092] Illustratively, the value of L is 0.5 mm, 1 mm, 5 mm, 10 mm, 20 mm, 30 mm, or 50 mm.

[0093] In some embodiments, the value of L is between 0.5 mm and 10 mm.

[0094] In some embodiments, when the battery cell 10 experiences thermal runaway, the pressure reduction mechanism 11 needs to perform a specific operation (e.g., rupture or fold back a part of the pressure reduction mechanism 11), thereby forming the discharge channel 111. Optionally, the value of L is 0.5 mm or more, thereby providing space for the operation of the pressure reduction mechanism 11, reducing the risk that the protective member 30 will interfere with the operation of the pressure reduction mechanism 11, and immediately reducing the pressure in the battery cell 10.

[0095] In some embodiments, when the battery cell 10 experiences thermal runaway, the pressure reduction mechanism 11 is activated and a pressure reduction channel 111 is formed. Optionally, the axial direction of the pressure reduction channel 111 is parallel to the thickness direction Z of the pressure reduction mechanism 11.

[0096] In some embodiments, the battery 2 further includes a housing 20 in which the battery cells 10 and the protective member 30 are housed.

[0097] The housing 20 may be an outer package of the battery 2, and the battery cells 10 are located inside the outer package. The housing 20 can prevent liquids or other foreign objects from affecting the charging and discharging of the battery cells 10.

[0098] The pressure reducing mechanism 11 of the battery cell 10 may face the bottom wall 20 b of the housing 20 , the ceiling wall 20 a of the housing 20 , or the side wall 20 c of the housing 20 .

[0099] In some embodiments, the protective member 30 is fixed to the surface of the housing 20 facing the pressure reducing mechanism 11. The housing 20 can fix the protective member 30, thereby reducing the risk of the protective member 30 moving due to the impact of high-temperature, high-velocity materials, reducing the probability of the protective member 30 being damaged by a collision, and reducing the risk of the protective member 30 losing its protective function. The protective member 30 blocks materials released from the battery cells 10, thereby reducing the thermal shock received by the housing 20 and reducing the amount of heat transferred to the housing 20, reducing the risk of the housing 20 melting and being penetrated, thereby improving the safety of the battery 2.

[0100] In some embodiments, the protective member 30 is secured to the housing 20 by gluing, welding, connecting with fasteners, or engaging with the housing 20. Of course, the protective member 30 may be secured to the housing 20 in other ways.

[0101] In some embodiments, the thermal shock resistance of the protective member 30 is superior to that of the housing 20. Thermal shock resistance refers to the ability of a material to withstand a sudden change in temperature without breaking. In other words, when subjected to the same high-temperature, high-velocity impact of a substance, the protective member 30 is less likely to break than the housing 20.

[0102] In some embodiments, the protective member 30 can provide thermal insulation and reduce the amount of heat transferred to the housing 20. Even if the battery cell 10 experiences thermal runaway, the presence of the protective member 30 reduces the amount of heat transferred to the housing 20, and therefore embodiments of the present application can reduce the requirements for the material of the housing 20. For example, the housing 20 may be made of a material that is not heat-resistant, such as a polyester material. Of course, the housing 20 may also be made of a heat-resistant material, such as aluminum, steel, or other metals.

[0103] In some embodiments, the material of protective member 30 includes at least one of an inorganic salt, an inorganic ceramic, an elemental metal, elemental carbon, and an organic colloid.

[0104] In some embodiments, the inorganic salt comprises a silicate. Optionally, the material of the protective member 30 comprises mica.

[0105] In some embodiments, the inorganic ceramic comprises at least one of aluminum oxide, silicon oxide, boron carbide, boron nitride, silicon carbide, silicon nitride, and zirconium oxide.

[0106] In some embodiments, the metal-based material comprises at least one of copper, iron, aluminum, tungsten, and titanium.

[0107] In some embodiments, the elemental carbon comprises at least one of amorphous carbon and graphite.

[0108] In some embodiments, the organic colloid comprises at least one of an epoxy resin structural adhesive, an acrylate structural adhesive, a polyimide structural adhesive, a maleimide structural adhesive, a polyurethane structural adhesive, and an acrylic structural adhesive.

[0109] In some embodiments, the material of protective member 30 includes at least two of an inorganic salt, an inorganic ceramic, an elemental metal, elemental carbon, and an organic colloid.

[0110] A composite structure formed from multiple materials can improve the thermal shock resistance and thermal insulation performance of the protective member 30.

[0111] In some embodiments, the protective member 30 comprises a carbon fiber plate formed from a carbon fiber cloth and an organic colloid.

[0112] In some embodiments, the protective member 30 comprises a resin sheet formed from inorganic ceramic powders and organic colloids.

[0113] In some embodiments, protective member 30 includes a graphite layer and a metal layer arranged in a stacked fashion.

[0114] In some embodiments, the protective member 30 comprises a composite fiber sheet made of carbon fiber and ceramic fiber.

[0115] In some embodiments, the protective member 30 includes a ceramic layer and a metal net connected to the ceramic layer.

[0116] In some embodiments, the melting point of the protective member 30 is higher than the melting point of the housing 20. The protective member 30 has better thermal shock resistance to the housing 20, providing heat protection and reducing the risk of the housing 20 being damaged.

[0117] In some embodiments, the melting point of the protective member 30 is higher than 1000° C. The protective member 30 has a high melting point and is less likely to melt when subjected to thermal shock, so that the protective member 30 has good thermal shock resistance and reduces the risk of the protective member 30 being pierced.

[0118] In some embodiments, the melting point of the protective member 30 is greater than 1500°C.

[0119] In some embodiments, the battery cell 10 includes an outer case 12, an electrode assembly 13, an electrolyte, and other functional components, and the electrode assembly 13 and the electrolyte are contained within the outer case 12 of the battery cell 10. The pressure reducing mechanism 11 is provided in the outer case 12.

[0120] The outer case 12 may be a hard outer case, for example, the outer case 12 may be made of an aluminum alloy, or the outer case 12 may be a soft outer case, for example, the outer case 12 may be made of an aluminum laminate film.

[0121] In some embodiments, the battery cell 10 includes a first wall 12a, and the pressure reducing mechanism 11 is disposed on the first wall 12a. The pressure reducing mechanism 11 may be fixed to the first wall 12a by welding, gluing, or other methods, or the pressure reducing mechanism 11 and the first wall 12a may be integrally formed.

[0122] The first wall 12 a may be a case wall having a constant thickness that faces the protective member 30 of the outer case 12 .

[0123] The first wall 12 a of the battery cell 10 may face the bottom wall 20 b of the housing 20 , the top wall 20 a of the housing 20 , or the side wall 20 c of the housing 20 .

[0124] In some embodiments, the thickness direction Z of the pressure reducing mechanism 11 is parallel to the thickness direction of the first wall 12a.

[0125] In some embodiments, the first wall 12a has a through-hole, and the pressure reducing mechanism 11 is accommodated in and seals the through-hole. Optionally, the through-hole is a stepped hole, and the pressure reducing mechanism 11 is fixed to the stepped surface.

[0126] In some embodiments, the outer surface of the pressure reducing mechanism 11 is recessed relative to the outer surface of the first wall 12a. In some embodiments, the pressure reducing mechanism 11 may be concealed, thereby reducing the risk of the pressure reducing mechanism 11 being damaged by components external to the battery cell 10.

[0127] In some embodiments, the battery cell 10 includes electrode terminals 14, which are attached to the outer case 12 and are used to electrically connect with the electrode assembly 13. The electrode terminals 14 are used to electrically connect the electrode assembly 13 with a circuit external to the battery cell 10, thereby enabling charging and discharging of the battery cell 10. Illustratively, there may be multiple electrode terminals 14.

[0128] In some embodiments, the battery cell 10 includes a first wall 12a, a second wall 12b, and a third wall 12c, the pressure reducing mechanism 11 is provided in the first wall 12a, the second wall 12b is located on a side of the first wall 12a away from the protective member 30, and the third wall 12c connects the first wall 12a and the second wall 12b. The battery cell 10 further includes an electrode terminal 14, which is installed on at least one of the first wall 12a, the second wall 12b, and the third wall 12c.

[0129] The third wall 12c may be one or more. In some embodiments, the battery cell 10 is a cylindrical battery cell and the third wall 12c is one and cylindrical, while in other examples, the battery cell 10 is a rectangular battery cell and the third wall 12c is multiple, and the multiple third walls 12c are arranged along the circumferential direction of the first wall 12a to form a rectangular tube.

[0130] There may be a plurality of electrode terminals 14, and the plurality of electrode terminals 14 may include a positive electrode terminal and a negative electrode terminal. In some embodiments, the positive electrode terminal and the negative electrode terminal are installed on the same wall of the battery cell 10, for example, the first wall 12a, the second wall 12b, or the third wall 12c. In another example, the positive electrode terminal and the negative electrode terminal are installed on two walls of the battery cell 10, respectively, for example, the positive electrode terminal and the negative electrode terminal are installed on the first wall 12a and the second wall 12b, respectively, or the positive electrode terminal and the negative electrode terminal are installed on the first wall 12a and the third wall 12c, respectively, or the positive electrode terminal and the negative electrode terminal are installed on the second wall 12b and the third wall 12c, respectively.

[0131] Optionally, as shown in FIG. 3, both the positive and negative electrode terminals are attached to the first wall 12a.

[0132] In some embodiments, the protective member 30 is a flat plate structure, which is easy to mold and install.

[0133] For example, the thickness of the protection member 30 is 0.5 mm to 5 mm.

[0134] The thinner the protective member 30, the higher the risk of the protective member 30 being penetrated by a high-temperature, high-velocity substance. The thicker the protective member 30, the lower the risk of the protective member 30 being penetrated by a high-temperature, high-velocity substance, but the protective member 30 will occupy more space and be heavier in the battery 2. By limiting the thickness of the protective member 30 to 0.5 mm to 5 mm, the inventors have reduced redundancy in the size design of the protective member 30, reduced the loss of energy density in the battery 2, and made it easier to form the protective member 30, thereby improving the safety of the battery 2, while still meeting the requirement of heat protection.

[0135] FIG. 7 is a structural schematic diagram of a battery according to some embodiments of the present application.

[0136] As shown in FIG. 7, in some embodiments, there are multiple battery cells 10.

[0137] The pressure reduction mechanisms 11 of the multiple battery cells 10 may face the same side, and for example, all of the pressure reduction mechanisms 11 of the multiple battery cells 10 face the ceiling wall 20a of the housing 20. Alternatively, the pressure reduction mechanisms 11 of the multiple battery cells 10 may face different sides, and for example, the pressure reduction mechanisms 11 of some of the battery cells 10 face the ceiling wall 20a of the housing 20, and the pressure reduction mechanisms 11 of some of the battery cells 10 face the bottom wall of the housing 20.

[0138] The protective member 30 may be one or more.

[0139] In some embodiments, there is only one protective member 30, and the protective member 30 includes multiple protective areas 31, which correspond one-to-one to the pressure reducing mechanisms 11 of the multiple battery cells 10. The protective member 30 can cover the pressure reducing mechanisms 11 of the multiple battery cells 10 simultaneously.

[0140] In another example, the number of protective members 30 and the number of battery cells 10 are the same, each protective member 30 includes one protective area 31, and the protective areas 31 of the multiple protective members 30 correspond one-to-one to the pressure reduction mechanisms 11 of the multiple battery cells 10. Each protective member 30 covers only the pressure reduction mechanism 11 of one battery cell 10.

[0141] In yet another example, there are a plurality of protective members 30, and each protective member 30 includes at least two protective regions 31. Each protective member 30 can cover the pressure reducing mechanisms 11 of at least two battery cells 10.

[0142] In yet another example, there are multiple protective members 30, and some of the protective members 30 include only one protective area 31, while the remaining protective members 30 include at least two protective areas 31. Some protective members 30 can cover only the pressure reduction mechanism 11 of one battery cell 10, while other protective members 30 can cover the pressure reduction mechanisms 11 of at least two battery cells 10.

[0143] In some embodiments, there are multiple battery cells 10, and the protective member 30 is located on the same side of the pressure reduction mechanisms 11 of the multiple battery cells 10. The protective member 30 includes multiple protective areas 31, and the multiple protective areas 31 correspond one-to-one to the pressure reduction mechanisms 11 of the multiple battery cells 10.

[0144] The protective member 30 can cover the pressure reduction mechanisms 11 of the multiple battery cells 10, and no matter which battery cell 10 experiences thermal runaway, the protective member 30 can block high-temperature, high-velocity materials, thereby reducing safety risks.

[0145] FIG. 8 is a structural schematic diagram of a battery according to another embodiment of the present invention.

[0146] As shown in FIG. 8, a flow path 32 for allowing the heat exchange medium to flow is provided inside the protective member 30.

[0147] The heat exchange medium may be a liquid or a gas, and alternatively, the heat exchange medium may be water, a mixture of water and ethylene glycol, or air.

[0148] When the heat exchange medium flows through the flow path 32, it can exchange heat with the battery cells 10 through the protective member 30, thereby regulating the temperature of the battery cells 10 so that the battery cells 10 operate within an appropriate temperature range. Of course, the heat exchange medium can also exchange heat with other components of the battery 2 through the protective member 30.

[0149] The protective member 30 of the embodiment of the present application can simultaneously perform the protective function and the heat management function, thereby contributing to simplifying the structure of the battery 2 and improving the energy density of the battery 2.

[0150] In some embodiments, when a substance released from the battery cell 10 acts on the wall of the flow path 32, the wall of the flow path 32 melts to form an opening, and the heat exchange medium in the flow path 32 is injected into the inside of the battery cell 10 through the opening and the pressure reduction flow path of the pressure reduction mechanism 11, thereby cooling the battery cell 10, mitigating reactions inside the battery cell 10, and reducing safety risks.

[0151] In some embodiments, the protective member 30 further includes a heat exchange area 33, the battery cell 10 further includes a first wall 12a, and the pressure reducing mechanism 11 is provided on the first wall 12a. The heat exchange area 33 is connected to the first wall 12a, thereby exchanging heat with the first wall 12a.

[0152] The flow passage 32 may be provided in a heat exchange area 33 .

[0153] The heat exchange area 33 may be directly connected to the first wall 12a, or may be indirectly connected to the first wall 12a via another heat conducting structure.

[0154] The heat exchange area 33 exchanges heat with the first wall 12a to adjust the temperature of the battery cell 10, allowing the battery cell 10 to operate within an appropriate temperature range and improving the cycle characteristics of the battery cell 10.

[0155] In some embodiments, the battery 2 further includes a heat-conducting structure 40, at least a portion of which is located between the first wall 12a and the heat exchange area 33 and connects the first wall 12a and the heat exchange area 33.

[0156] The heat conducting structure 40 can connect the first wall 12a and the heat exchange area 33, thereby stabilizing the heat exchange between the first wall 12a and the heat exchange area 33. The heat conducting structure 40 can further support the protective member 30, thereby spacing the protective member 30 away from the pressure reducing mechanism 11.

[0157] In some embodiments, the heat transfer structure 40 comprises a thermally conductive adhesive that bonds the first wall 12a and the heat exchange area 33 together.

[0158] In some embodiments, the first wall 12a faces the bottom wall 20b of the housing 20, and the protective member 30 is located below the first wall 12a. The electrode terminal 14 is installed on the second wall 12b.

[0159] FIG. 9 is a structural schematic diagram of a battery according to another embodiment of the present invention.

[0160] 9 , in some embodiments, the battery cell 10 further includes a first wall 12a, and the pressure reducing mechanism 11 is provided on the first wall 12a. The protective member 30 includes a main body 34 and a support 35. The main body 34 is spaced apart from the first wall 12a along the thickness direction Z, and the support 35 is located between the first wall 12a and the main body 34 and is used to connect the first wall 12a and the main body 34. The main body 34 includes a protective region 31.

[0161] The support portion 35 may be one or more.

[0162] The support portion 35 and the body portion 34 may be of one piece, or alternatively, the support portion 35 and the body portion 34 may be two separately molded pieces that are joined together by gluing, abutting, welding, or other methods.

[0163] The support portion 35 not only fixes the main body portion 34 to the battery cell 10, but also separates the protective area 31 from the pressure reduction mechanism 11. By adjusting the size of the support portion 35, the minimum distance L between the pressure reduction mechanism 11 and the protective area 31 can be adjusted.

[0164] In some embodiments, the protective member 30 is located below the battery cell 10, and the protective member 30 provides support to the battery cell 10. Illustratively, the support 35 may be attached to the underside of the battery cell 10, thereby fixing the battery cell 10 to the upper side of the protective member 30.

[0165] FIG. 10 is a structural schematic diagram of a battery according to another embodiment of the present invention.

[0166] 10, in some embodiments, the first wall 12a of the battery cell 10 faces the top wall 20a of the housing 20, and the second wall 12b faces the bottom wall 20b of the housing 20. The electrode terminal 14 is attached to the third wall 12c.

[0167] According to some embodiments of the present application, the present application further provides a power consuming device including the battery of any of the above embodiments used to supply electrical energy. The power consuming device may be any of the above devices or systems that use a battery.

[0168] According to some embodiments of the present application, referring to Figures 3 to 6, the present application provides a battery 2 including a battery cell 10, a housing 20, and a protective member 30, wherein the battery cell 10 and the protective member 30 are housed within the housing 20.

[0169] The battery cell 10 includes a first wall 12a and a pressure reduction mechanism 11 provided on the first wall 12a, and the first wall 12a faces the top wall 20a of the housing 20. The protective member 30 has a flat plate structure and is fixed to the top wall 20a of the housing 20. The protective member 30 includes a protective area 31 facing the pressure reduction mechanism 11 in the thickness direction Z of the pressure reduction mechanism 11, and the protective area 31 is used to block at least some of the substances released from the battery cell 10 through the pressure reduction mechanism 11.

[0170] The weight energy density of the battery cell 10 is E, and the minimum distance between the pressure reducing mechanism 11 and the protection area 31 in the thickness direction Z is L. E and L satisfy 2Wh / (kg·mm)≦E / L≦7010Wh / (kg·mm).

[0171] The present application will now be further described with reference to the following examples.

[0172] In order to clarify the objectives, technical solutions and beneficial effects of the present invention, the present invention will be described in more detail below with reference to examples. However, it should be understood that the examples of the present invention are only for illustrating the present invention and are not intended to limit the present invention, and the examples of the present invention are not limited to the examples shown in the specification. In the examples, the specific experimental conditions or operating conditions are not specified, and the products are prepared under normal conditions or under the conditions recommended by the material supplier.

[0173] Example 1:

[0174] (i) Referring to Figures 6 and 11, four rectangular battery cells 10 were manufactured, each having a length l1 of 220 mm, a width l2 of 44 mm, and a height l3 of 100 mm. In the thickness direction Z of the pressure reduction mechanism 11, the outer surface of the pressure reduction mechanism 11 and the outer surface of the first wall 12a are flush with each other.

[0175] (ii) The weight energy density E of the battery cell 10 was measured and found to be 100 Wh / kg.

[0176] (iii) The four battery cells 10 are arranged in order along the width direction (i.e., the direction of size l2), and a 5 mm thick heat insulating pad 50 is placed between adjacent battery cells 10. The heat insulating pad 50 is adhered to the battery cells 10.

[0177] (iv) Four battery cells 10 are placed inside a sealed housing 20, and a protective member 30 is attached to the wall of the housing 20 located above the battery cells 10 (hereinafter referred to as the ceiling wall 20a of the housing 20). The protective member 30 is a flat plate with a thickness of 4 mm, made of a composite plate made of boron nitride and carbon fiber. The size H of the housing 20's storage cavity in the height direction (i.e., the direction of size l3, which is parallel to the thickness direction of the pressure reduction mechanism 11) is 104.2 mm. Measurements and calculations revealed that the minimum gap L between the protective member 30 and the pressure reduction mechanism 11 in the height direction was 0.2 mm. The space utilization rate T of the battery cells 10 in the height direction was calculated to be T = l3 / H.

[0178] (v) Trigger thermal runaway in one battery cell 10 in the center of the casing 20, and release a substance from the battery cell 10 to the outside, for example, by pricking the battery cell 10 with a needle or by heating the battery cell 10, causing the battery cell 10 to go into thermal runaway. After holding for one hour, observe whether the other three battery cells 10 go into thermal runaway or not, and record the number M of the three battery cells 10 that go into thermal runaway.

[0179] Examples 2 to 16: The test methods for Examples 2 to 16 refer to Example 1, and the differences between Examples 2 to 16 and Example 1 are as shown in Table 1. For example, the weight energy density E of the battery cell may be adjusted by adjusting the chemical system of the battery cell. The minimum distance L between the protective member and the pressure reducing mechanism may be changed by changing the size H of the housing.

[0180] Comparative Examples 1 to 4: The test methods for Comparative Examples 1 to 4 refer to Example 1, and the differences between Comparative Examples 1 to 4 and Example 1 are as shown in Table 1.

[0181] [Table 1]

[0182] With reference to Examples 1 to 16 and Comparative Examples 1 and 2, the examples of the present application limit the value of E / L to 2 Wh / (kg·mm) or more, thereby reducing excessive design of the distance between the pressure reducing mechanism and the protective member, improving the space utilization rate inside the battery, and reducing waste of the battery's energy density.

[0183] With reference to Examples 1 to 16 and Comparative Examples 3 and 4, the examples of the present application limit the E / L value to 7010 Wh / (kg·mm) or less, thereby reducing the thermal impact on other battery cells even if a specific battery cell experiences thermal runaway, thereby reducing the risk of other battery cells experiencing thermal runaway and improving safety.

[0184] The embodiments and features of the embodiments in the present application can be combined with each other as long as they are not contradictory.

[0185] Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present application, and are not intended to limit the same. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand the following: Those skilled in the art may still modify the technical solutions described in the above embodiments or substitute some technical features therein with equivalents, but such modifications or substitutions shall not cause the substance of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. a battery cell including a pressure reducing mechanism; a protective region facing the pressure reduction mechanism in a thickness direction of the pressure reduction mechanism, the protective region including a protective member used to block at least a portion of a substance released from the battery cell through the pressure reduction mechanism; When the weight energy density of the battery cell is E and the minimum distance between the pressure reducing mechanism and the protection area in the thickness direction is L, E and L are expressed as follows: The condition 2Wh / (kg mm)≦E / L≦7010Wh / (kg mm) is satisfied. a housing, the battery cell and the protective member being housed in the housing; The protective member is fixed to the surface of the housing facing the pressure reducing mechanism.

2. E and L are The battery according to claim 1, wherein 10 Wh / (kg·mm)≦E / L≦800 Wh / (kg·mm) is satisfied.

3. 2. The battery of claim 1, wherein the value of E is between 100 Wh / kg and 3505 Wh / kg.

4. 4. The battery of claim 3, wherein the value of E is between 100 Wh / kg and 400 Wh / kg.

5. 2. The battery according to claim 1, wherein the value of L is 0.5 mm to 50 mm.

6. 6. The battery according to claim 5, wherein the value of L is 0.5 mm to 10 mm.

7. The battery according to claim 1 , wherein a flow path for flowing a heat exchange medium is provided inside the protective member.

8. the protective member further includes a heat exchange area, the battery cell further includes a first wall, and the pressure reducing mechanism is provided on the first wall; 8. The battery of claim 7, wherein the heat exchange area is connected to the first wall and thereby in heat exchange with the first wall.

9. 9. The battery of claim 8, further comprising a thermally conductive structure, at least a portion of said thermally conductive structure being located between said first wall and said heat exchange area and connecting said first wall and said heat exchange area.

10. the battery cell further includes a first wall, and the pressure reducing mechanism is provided in the first wall; the protective member includes a main body portion and a support portion, the main body portion is installed at a distance from the first wall along the thickness direction, the support portion is located between the first wall and the main body portion and is used to connect the first wall and the main body portion, The battery of claim 1 , wherein the body portion includes the protective area.

11. The battery according to claim 1 , wherein the protective member has a flat plate structure.

12. the battery cell is plural, and the protective member is located on the same side of the pressure reducing mechanism for the plural battery cells; The battery according to claim 1 , wherein the protective member includes a plurality of the protective areas, and the plurality of protective areas correspond one-to-one to the pressure reduction mechanisms of the plurality of battery cells.

13. the battery cell includes a first wall, a second wall, and a third wall, the pressure reduction mechanism is provided in the first wall, the second wall is located on a side of the first wall away from the protective member, and the third wall is connected to the first wall and the second wall, The battery according to claim 1 , wherein the battery cell further includes an electrode terminal, the electrode terminal being disposed on at least one of the first wall, the second wall, and the third wall.

14. 2. The battery according to claim 1, wherein the material of the protective member includes at least one of an inorganic salt, an inorganic ceramic, an elemental metal, elemental carbon, and an organic colloid.

15. A power consuming device comprising a battery according to any one of claims 1 to 14 for supplying electrical energy thereto.

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