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] TECHNICAL FIELD 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 the performance of batteries, 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 the safety of batteries is a technical issue that needs to be resolved as soon as possible in battery technology. Summary of the Invention

[0003] The present application provides batteries and power consuming devices 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 a portion of a substance 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 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 violent the chain reaction that occurs inside the battery cell, and the higher the temperature and speed of the material released from the battery cell; therefore, the larger the value of E, the higher the requirements for the minimum distance L between the pressure reducing mechanism and the protection area. If E is large and L is small, particulate matter in the high-temperature and high-velocity material is likely to accumulate on the thermal runaway battery cell and spread onto the normal battery cell, and even bounce back onto the normal battery cell, which not only brings about the risk of burning and damaging the normal battery cell, but also increases the temperature of the normal battery cell, causing the risk of thermal runaway for the normal battery cell, and thus posing a safety risk. If E is small and L is large, the distance between the pressure reducing mechanism and the protection area is overdesigned, which reduces the space utilization rate inside the battery and results in a waste of the energy density of the battery. 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 energy density of the battery, and improving the safety of the battery, all on the premise of meeting the requirements for battery safety protection.

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

[0007] In some embodiments, the value of E is 100Wh / kg to 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, and the driving capability of the power consumption device using the battery can be improved. If the weight energy density of the battery cell is 3505Wh / kg or less, the battery cell that has gone into thermal runaway can be brought into a controllable state, and the safety risk can be reduced.

[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 design redundancy of the distance between the protective member and the pressure reducing mechanism, reducing the loss of energy density of the battery, and improving the safety of the battery, on the premise of 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 passage for the flow of the heat exchange medium therein, and the protective member can simultaneously perform a protection function and a heat management function, thereby contributing to 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 reducing 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. The heat exchange area exchanges heat with the first wall to adjust the temperature of the battery cell so that the battery cell operates within a suitable temperature range and improve 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 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 body portion and a support portion, the body portion is spaced apart from the first wall along the thickness direction, and the support portion is located between the first wall and the body portion and is used to connect the first wall and the body portion. The body portion 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 protection regions, and the multiple protection 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 play a role in blocking high-temperature and high-velocity materials, thereby reducing safety risks.

[0020] In some embodiments, the battery further includes a housing, the battery cell and the protective member being housed within the housing, the protective member being 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 also 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 being moved by the impact of high-temperature and high-velocity substances, reducing the probability of the protective member being damaged by impact, 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, the battery cell further includes an electrode terminal, and the electrode terminal is 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 includes at least one of an inorganic salt, an inorganic ceramic, an elemental metal, an elemental carbon, and an organic colloid.

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

[0025] In order to more clearly describe the technical solutions in the embodiments of the present application, the following provides a brief description of 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 creative efforts.

[0026] [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Diagram 2] FIG. 1 is an exploded schematic diagram of a battery according to some embodiments of the present application. [Diagram 3] FIG. 1 is a structural schematic diagram of a battery according to some embodiments of the present application. [Figure 4] FIG. 4 is another structural schematic diagram of the battery shown in FIG. 3, where the pressure reducing mechanism of the battery cell of the battery is in an operating state. [Diagram 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] FIG. 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] FIG. 2 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 PREFERRED EMBODIMENTS

[0028] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described below with reference to the drawings in the embodiments of the present application, and obviously, the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative efforts are all within the scope of protection of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art. The terms used in this application are merely for the purpose of describing specific embodiments and are not intended to limit the present application. The terms "include" and "have" and their equivalents in the description of the present application and claims and the above drawings are intended to be non-exclusive. The terms "first", "second", etc. in the description of the present application and claims or the above drawings are used to distinguish different objects and are not used to describe a specific order or subordinate relationship.

[0030] Reference to an "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The 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] What should be explained in the description of this application is that unless otherwise clearly specified and limited, the terms "attach", "connected", "connection" and "attachment" should be understood in a broad sense, for example, they may be fixedly connected, detachably connected, or integrally connected. They may be directly connected, indirectly connected through an intermediate medium, or internally connected between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific situation.

[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 denote the same components, and in different embodiments, detailed descriptions of the same components will be omitted for the sake of brevity. Note that the dimensions such as thickness, length, width, etc. of each component in the embodiments of the present application and the dimensions such as thickness, length, width, etc. of the entire integrated device 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 the case where something is absolutely parallel, but also includes the situation where the common engineering perception is that something is approximately parallel, and at the same time, the term "perpendicular" not only includes the case where something is absolutely vertical, but also includes the situation where the common engineering perception is that something is approximately vertical.

[0036] In the present application, the battery cells may include lithium ion battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells, magnesium ion battery cells, etc., and the embodiments of the present application are not limited thereto. The battery cells may be cylindrical, flat, rectangular, or other shapes, and the embodiments of the present application are not limited thereto. The battery cells may be hard case battery cells, soft pack battery cells, or other types of battery cells.

[0037] The 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 is mainly operated by the movement of metal ions between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is applied to the surface of the positive electrode collector, the positive electrode collector includes a positive electrode collector part and a positive electrode tab, the positive electrode active material layer is applied to the positive electrode collector part, and the positive electrode tab is not applied to the positive electrode active material layer. Taking a lithium-ion battery cell as an example, the material of the positive electrode collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is applied to the surface of the negative electrode collector, the negative electrode collector includes a negative electrode collector part and a negative electrode tab, the negative electrode active material layer is applied to the negative electrode collector part, and the negative electrode active material layer is not applied to the negative electrode tab. The material of the negative electrode collector may be copper, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may be carbon or silicon, etc. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc.

[0038] The battery referred to in the embodiments of this application refers to a single physical module that includes 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] In the development of battery technology, various design factors, such as performance parameters such as energy density, cycle life, discharge capacity, charge and discharge efficiency, must be considered simultaneously, and battery safety must also be taken into consideration.

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

[0041] The pressure reducing mechanism may be an element or member that operates when the battery cell reaches a certain condition. Exemplarily, the pressure reducing mechanism may be an element or member that operates when the internal pressure or internal temperature of the battery cell reaches a predetermined threshold to release the internal pressure and / or the internal substance. The design of the threshold varies according to 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, and may be, for example, 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 provided in the pressure reducing mechanism is ruptured to form a pressure reducing flow path for releasing the internal pressure. Alternatively, the pressure reducing mechanism may be a temperature-sensitive element or structure, and when the internal temperature of the battery cell reaches a predetermined threshold, the pressure reducing mechanism is activated to form a pressure reducing flow path for releasing the internal pressure. Alternatively, the pressure reducing mechanism may be an actively operable member, and for example, the pressure reducing mechanism may be activated when a control signal for the battery is received.

[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 flow 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] The term "activation" as used herein refers to the pressure reduction mechanism generating an action or being 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 part of the pressure reduction mechanism bursting, fracturing, tearing, opening, etc. When the pressure reduction mechanism is activated, the high-temperature and high-velocity material inside the battery cell is discharged as an emission from the activated point. In this manner, pressure can be released from the battery cell under a controllable pressure condition, avoiding the occurrence of a potential more serious accident.

[0045] Exhaust from battery cells as referred to in this application includes, but is 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 materials into the housing. The housing is also provided with a pressure reduction mechanism, and the pressure reduction mechanism of the housing is activated to discharge the waste materials to the outside of the housing at a set position.

[0047] The inventors have noted that the effluent discharged from the battery cells is at high temperature and high velocity, and the impact of the effluent may 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, so that the protective member can block the high-temperature and high-velocity substances released from the battery cell and withstand the impact of the high-temperature and high-velocity substances, thereby reducing the risk of the battery exploding and improving safety.

[0049] As a result of research, the inventors found that when particulate matter in the high-temperature, high-velocity material is blocked by the protective member, it bounces back or scatters around. 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., normal battery cells adjacent to the thermally runaway battery cell), or may bounce back to other components, thereby increasing the risk of destroying those components and creating a safety risk. In order to reduce the safety risk, the inventors tried to increase the distance between the pressure reducing mechanism and the protective member, but an increase in the distance reduces the space utilization rate inside the battery and reduces the energy density of the battery. If the distance between the pressure reducing mechanism and the protective member is overdesigned, it results in a waste of energy density. As a result of further research, the inventors also found that when the battery cell goes into thermal runaway, the weight energy density of the battery cell is related to the temperature and speed of the material released from the battery cell, and the higher the weight energy density of the battery cell, the easier it is for particulate matter in the high-temperature, high-velocity material to accumulate and destroy other components adjacent to the thermally 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 gravitational 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 consumption device may be a vehicle, a mobile phone, a mobile device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a gasoline vehicle, a natural gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle, etc. The spacecraft includes an aircraft, a rocket, a space shuttle, a space ship, etc. The electric toy includes a game console, an electric car toy, an electric ship toy, an electric aircraft toy, and other stationary or mobile electric toys. The electric tool includes a metal cutting electric tool, a polishing electric tool, an assembly electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an electric impact driver, a concrete vibrator, and an electric planer. The embodiment of the present application is not particularly limited to the above power consumption device.

[0053] For convenience of explanation, the following embodiment will be described taking 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 start-up, 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 diagram 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 a battery cell 10 , and the battery cell 10 is housed within 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, where the first housing portion 21 and the second housing portion 22 are fitted over each other, and the first housing portion 21 and the second housing portion 22 together define a housing space for housing the battery cells 10.

[0061] In some embodiments, the second housing portion 22 may be a hollow structure with one end open, and the first housing portion 21 may be a plate-like structure, with the first housing portion 21 covering the open side of the second housing portion 22 to form the housing 20 having the storage space. In another embodiment, the first housing portion 21 and the second housing portion 22 may both be hollow structures with one end open, with the open side of the first housing portion 21 covering the open side of the second housing portion 22 to form the housing 20 having the storage 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 sealing material 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] In the battery 2, the battery cell 10 may be one or more. If there are more than one battery cell 10, the battery cells 10 may be connected in series, in parallel, or in series-parallel, and a series-parallel connection means that the battery cells 10 are connected in parallel as well as in series. The battery cells 10 may be directly connected in series, in parallel, or in series-parallel, and then the entire battery cell 10 may be housed in the housing 20. Note that the battery cells 10 may first be connected in series, in parallel, or in series-parallel to form a battery module, and the battery modules may be further connected in series, in parallel, or in series-parallel to be integrally formed 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 a pressure reducing mechanism of a battery cell of the battery 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 application 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 a portion of the material 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 2Wh / (kg·mm)≦E / L≦7010Wh / (kg·mm).

[0068] There may be one or more battery cells 10. Exemplarily, 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 operates and forms a pressure reduction path 111. Substances 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 is intended to withstand the thermal shock of high-temperature, high-velocity substances discharged from the battery cells 10. Even when subjected to the thermal shock of high-temperature, high-velocity substances discharged from the battery cells 10, the protective member 30 will not melt or be penetrated or explode, and will fulfill its protective role.

[0071] The protective member 30 may be a functional member in the battery 2, may only perform the function of protection from heat, or may perform other functions while performing the function of protection from heat. 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 serve to block high-temperature and high-velocity substances emitted from the battery cells 10. In another example, the protective member 30 may be a part of the outer package of the battery 2. In another example, the protective member 30 is an independent member connected to the outer package of the battery cells 10 or the battery 2.

[0072] The protective region 31 is a portion of the protective member 30 that overlaps with the decompression mechanism 11 in the thickness direction Z. Exemplarily, a projection of the protective region 31 in the thickness direction Z completely overlaps with a 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 multiple protective areas 31 of the protective member 30 may face 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. Exemplarily, 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 members may be present between the protective area 31 and the pressure reduction mechanism 11. The thermal shock resistance performance of the protective member 30 is superior to the thermal shock resistance performance 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 a high-temperature and high-velocity substance released from the battery cell 10.

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

[0077] The protective member 30 may be of one-piece structure, or may be of 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 embodiments of the present application are not limited in this respect.

[0079] The gravimetric energy density E of the battery cell 10 has units of 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 the battery cell 10, the larger the value of E, the more violent the chain reaction occurring inside the battery cell 10, and the higher the temperature and speed of the material 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 protection area 31. If E is large and L is small, particulate matter in the high-temperature and high-velocity material is likely to accumulate on the thermal runaway battery cell 10 and spread onto the normal battery cell 10, and is also likely to bounce back onto the normal battery cell 10, which not only brings about the risk of burning and damaging the normal battery cell 10, but also raises the temperature of the normal battery cell 10, causing the risk of thermal runaway of the normal battery cell 10, and thus posing a safety risk. If E is small and L is large, the distance between the pressure reducing mechanism 11 and the protection area 31 is overdesigned, which reduces the space utilization rate inside the battery 2 and results in a waste of energy density of the battery 2.

[0081] As a result of the inventors' research, by limiting the value of E / L to 2 Wh / (kg·mm) to 7010 Wh / (kg·mm), while still satisfying the requirements for safety protection of battery 2, it is possible to reduce the design redundancy of the distance between protective member 31 and pressure reduction mechanism 11, reduce the loss of energy density of battery 2, and improve the safety of 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 10Wh / (kg·mm)≦E / L≦800Wh / (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, and the driving range of the power consumption device using the battery 2 can be improved. 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, and safety risks can be reduced.

[0086] Illustratively, the value of E is 100Wh / kg, 200Wh / kg, 300Wh / kg, 400Wh / kg, 600Wh / kg, 1000Wh / kg, 2000Wh / kg, 3000Wh / kg or 3505Wh / 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 and damaging the normal battery cells 10, but also increases the temperature of the normal battery cells 10, causing the risk of thermal runaway in the normal battery cells 10 and posing a safety risk. If L is too large, the distance between the pressure reducing mechanism 11 and the protected area 31 is over-designed, which reduces the space utilization rate inside the battery 2 and results in a waste of energy density in the battery 2.

[0090] In the embodiments of the present application, by limiting the value of L to 0.5 mm to 50 mm, the design redundancy of the distance between the protective member 31 and the pressure reduction mechanism 11 is reduced, the loss of energy density of the battery 2 is reduced, and the safety of the battery 2 is improved, all while satisfying 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 enabling smooth exhaust in the space between the protective member 30 and the pressure reduction mechanism 11, reducing the risk of not being able to exhaust immediately due to insufficient exhaust space, improving safety, and reducing the possibility of the 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 certain operation (e.g., rupture or fold back a part of the pressure reduction mechanism 11), thereby forming the discharge flow path 111. Optionally, the value of L is 0.5 mm or more, thereby providing a space for the operation of the pressure reduction mechanism 11, reducing the risk that the protective member 30 interferes with the operation of the pressure reduction mechanism 11, and immediately depressurizing 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 , may face the ceiling wall 20 a of the housing 20 , or may face 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 that the protective member 30 will move due to the impact of high-temperature and high-velocity substances, reducing the probability that the protective member 30 will be damaged due to a collision, and reducing the risk that the protective member 30 will lose its protective function. The protective member 30 can reduce the thermal shock received by the housing 20 by blocking substances released from the battery cells 10, and also reduces the amount of heat transferred to the housing 20, reducing the risk that the housing 20 will melt and be 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 manners.

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

[0102] In some embodiments, the protective member 30 can act as a heat insulator and reduce the amount of heat transferred to the housing 20. Even if the battery cell 10 experiences thermal runaway, the amount of heat transferred to the housing 20 is small due to the presence of the protective member 30, and therefore the embodiments of the present application can reduce the requirements for the material of the housing 20. Exemplarily, 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 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, an 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 certain 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 includes 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, an elemental carbon, and an organic colloid.

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

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

[0112] In some embodiments, protective member 30 includes 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, 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 performance for the housing 20, and provides a protection function from heat, 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 performance 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 secured 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 , may face the ceiling wall 20 a of the housing 20 , or may face 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 is provided with 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. Embodiments of the present application may conceal the pressure reducing mechanism 11, thereby reducing the risk that the pressure reducing mechanism 11 will be damaged by components external to the battery cell 10.

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

[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, and the electrode terminal 14 is provided 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 disposed along the circumferential direction of the first wall 12a and form a rectangular tube.

[0130] The electrode terminal 14 may be multiple, and the multiple 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, 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 protective member 30 is 0.5 mm to 5 mm.

[0134] The smaller the thickness of 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 space and weight that the protective member 30 occupies in the battery 2 increases. By limiting the thickness of the protective member 30 to 0.5 mm to 5 mm, the inventors have reduced the redundancy of the size design of the protective member 30, reduced the loss of energy density of the battery 2, and reduced the difficulty of molding the protective member 30, thereby improving the safety of the battery 2, all on the premise that the requirements for protection from heat are met.

[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 regions 31, which correspond one-to-one to the pressure reduction mechanisms 11 of the multiple battery cells 10. The protective member 30 can cover the pressure reduction 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 a plurality of battery cells 10, and the protective member 30 is located on the same side of the pressure reduction mechanisms 11 of the plurality of battery cells 10. The protective member 30 includes a plurality of protective regions 31, and the plurality of protective regions 31 correspond one-to-one to the pressure reduction mechanisms 11 of the plurality of 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 and high-velocity substances, thereby reducing safety risks.

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

[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, etc.

[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 a protective function and a thermal 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 reduced pressure 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 in 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 passages 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 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 so that the battery cell 10 operates within an appropriate temperature range, thereby 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 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 heat 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 application.

[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 portion 34 and a support portion 35, the main body portion 34 is disposed at a distance from the first wall 12a along the thickness direction Z, and the support portion 35 is located between the first wall 12a and the main body portion 34 and is used to connect the first wall 12a and the main body portion 34. The main body portion 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 construction, or the support portion 35 and the body portion 34 may be two separately molded pieces that are bonded, abutted, welded, or otherwise connected together.

[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 under the battery cell 10, and the protective member 30 provides support to the battery cell 10. Exemplarily, 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 application.

[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, where 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 ceiling wall 20a of the housing 20. The protective member 30 has a flat plate structure and is fixed to the ceiling 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 a portion of the substance released from the battery cell 10 via 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 protected 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 make the objectives, technical solutions and beneficial effects of the present invention clearer, the present application will be described in more detail with reference to the following examples.However, it should be understood that the examples of the present application are only for illustrating the present application, and are not intended to limit the present application, and the examples of the present application are not limited to the examples shown in the specification.In the examples, those that do not specify specific experimental conditions or operating conditions are prepared under normal conditions or under conditions recommended by the material supplier.

[0173] Example 1:

[0174] (i) Referring to FIG. 6 and FIG. 11, four rectangular battery cells 10 are manufactured, and the length l of the battery cells 10 is measured. 1 is 220mm, width l 2 is 44mm, height l 3 In the thickness direction Z of the pressure reducing mechanism 11, the outer surface of the pressure reducing mechanism 11 and the outer surface of the first wall 12a are flush with each other.

[0175] (ii) The gravimetric 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 the width direction (i.e., size l 2 The battery cells 10 are arranged in order along the direction of the arrows (a) and (b), and a heat insulating pad 50 having a thickness of 5 mm is placed between adjacent battery cells 10. The heat insulating pad 50 is adhered to the battery cell 10.

[0177] (iv) The four battery cells 10 are placed in 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, and is made of a composite plate made of boron nitride and carbon fiber. 3 The size H of the pressure reducing mechanism 11 (the direction of the pressure reducing mechanism 11, which is parallel to the thickness direction of the pressure reducing mechanism 11) is 104.2 mm. As a result of measurement and calculation, the minimum distance L between the protective member 30 and the pressure reducing mechanism 11 in the height direction is 0.2 mm. The space utilization rate T of the battery cell 10 in the height direction is calculated as T=l 3 / H.

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

[0179] Examples 2-16: The test methods of Examples 2-16 refer to Example 1, and the differences between Examples 2-16 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 of Comparative Examples 1 to 4 refer to Example 1. 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 impact of heat on other battery cells even if a specific battery cell experiences thermal runaway, lowering the risk of other battery cells experiencing thermal runaway, and improving safety.

[0184] In addition, 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] The final point to be explained is as follows: 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 of the technical features therein for equivalents, but these modifications or substitutions will 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 reducing mechanism in a thickness direction of the pressure reducing 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 reducing mechanism; If 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: A battery that satisfies 2Wh / (kg.mm)≦E / L≦7010Wh / (kg.mm).

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

3. The battery according to claim 1 or 2, wherein the value of E is from 100 Wh / kg to 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. The battery according to any one of claims 1 to 4, wherein the value of L is from 0.5 mm to 50 mm.

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

7. The battery according to any one of claims 1 to 6, 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, thereby providing heat exchange with the first wall.

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

10. The battery cell further includes a first wall, the pressure reducing mechanism being provided on the first wall, the protective member includes a main body portion and a support portion, the main body portion is disposed 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 according to claim 1 , wherein the main body portion includes the protective area.

11. The battery according to any one of claims 1 to 6, wherein the protective member has a flat plate structure.

12. the battery cell is a plurality of cells, the protective member is located on the same side of the pressure reduction mechanism of the plurality of battery cells, The battery according to any one of claims 1 to 11, wherein the protective member includes a plurality of the protective regions, and the plurality of the protective regions correspond one-to-one to the pressure reducing mechanisms of the plurality of the battery cells.

13. The battery cell and the protective member are housed in the housing. The battery according to any one of claims 1 to 12, wherein the protective member is fixed to a surface of the housing facing the pressure reducing mechanism.

14. 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 any one of claims 1 to 13, 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.

15. The battery according to any one of claims 1 to 14, 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.

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

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