CN216354619U - Battery monomer, battery and power consumption device - Google Patents

Abstract

The embodiment of the application relates to the technical field of batteries, in particular to a battery monomer, a battery and an electric device. The battery cell includes a housing including a first housing layer and a second housing layer in a thickness direction of a housing wall of the housing, the second housing layer having a weak region such that the housing forms a pressure relief region at the weak region, the pressure relief region being configured to actuate to relieve an internal pressure of the battery cell when the internal pressure or temperature reaches a threshold value. The battery monomer, battery and power consumption device that this application embodiment provided, it is through setting up the pressure release district on the free shell of battery for the emission that the free thermal runaway of battery produced can directional emission, thereby extension thermal runaway spreads to the free time of other batteries, improves the safety in utilization of battery.

Description

Battery monomer, battery and power consumption device

Technical Field

The embodiment of the application relates to the technical field of batteries, in particular to a battery monomer, a battery and an electric device.

Background

In a device using a battery as a driving energy source, the battery is used as a core component, so that the guarantee of the use safety of the battery is important for guaranteeing the use safety of the whole device, and the thermal runaway of the battery is an important factor threatening the use safety of the battery.

In the use process of the current battery, when thermal runaway occurs in one battery cell, emissions are generated in the battery cell, the emissions contain substances such as high-temperature smoke (serious people generate open fire) and volatilized high-temperature electrolyte, and the emissions can be thermally diffused in the emission process, so that thermal runaway occurs in other battery cells, and even accidents such as explosion can be caused.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, embodiments of the present application provide a battery cell, a battery and an electric device, which enable emissions generated by thermal runaway of the battery cell to be discharged directionally by providing a pressure relief region on a housing of the battery cell, so as to prolong the time for thermal runaway to diffuse to other battery cells and improve the use safety of the battery.

According to a first aspect of embodiments of the present application, there is provided a battery cell including a housing, a first housing layer and a second housing layer along a thickness direction of a housing wall of the housing, the second housing layer having a weak region such that the housing forms a pressure relief region at the weak region, the pressure relief region being configured to actuate to relieve an internal pressure of the battery cell when the internal pressure or temperature reaches a threshold value.

By adopting the scheme, the strength of the shell at the pressure relief area is lower than that of the shell at other positions because the pressure relief area is formed at the position of the weak area, when the internal temperature or pressure of the battery monomer reaches the threshold value capable of actuating the pressure relief area, the pressure relief area is damaged before other positions of the shell, so that the internal temperature or pressure of the battery monomer is directionally released from the pressure relief area and is not easy to release from other positions of the shell, and when the battery monomer is assembled to form the battery, the orientation of the pressure relief area is adjusted, so that the emissions in the battery monomer after the pressure relief area is actuated can be directionally discharged towards a preset safe direction, the internal pressure of the battery monomer is prevented from being released towards other battery monomers or flammable and explosive components, the time of thermal diffusion is reduced, and the use safety of the battery is improved.

In some embodiments, the area of weakness extends along the length of the housing.

By adopting the scheme, when the amount of the emissions in the battery cell is large, the emissions can damage the shell of the battery cell along the length direction of the shell, so that the emissions with high temperature and high pressure can be limited in one direction, and the phenomenon that the shell is damaged along the circumferential direction of the shell to discharge internal pressure when the amount of the emissions is large, so that the emissions are discharged in the directions other than the preset direction to damage other battery cells is prevented.

In some embodiments, the area of weakness is configured as a notch provided on the second shell; alternatively, the weakened area is configured as a score provided on the second shell; or the thickness of the weak area is less than that of the position outside the weak area of the second shell layer.

By adopting the scheme, when the weak area is the notch, the shell of the pressure release area only comprises the first shell layer, and high-temperature and high-pressure emissions can be discharged from the pressure release area only by damaging the first shell layer. When the weakened area is a score, the score is more easily torn by the high temperature, high pressure discharge and is more easily discharged from the discharge area. When the weakened region has a thickness less than the thickness of the second shell elsewhere, the weakened region has a strength less than the strength of the second shell elsewhere, and high temperature and pressure emissions are more likely to damage the weakened region of the second shell and thus exit the pressure relief area.

In some embodiments, the second shell layer is adhesively attached to the first shell layer.

By adopting the scheme, the bondable area between the second shell layer and the first shell layer is larger, so that the second shell layer and the first shell layer are combined into a whole more easily, when the temperature or the air pressure in the single battery is increased, the first shell layer and the second shell layer are stressed integrally, the stress on each part is uniform, the situation that the part of one layer close to the inside of the single battery is broken at the position outside the pressure relief area due to the fact that the part of the one layer is not supported by the external layer is prevented, and then the external layer is broken, so that the effect of directional discharge from the pressure relief area cannot be achieved.

In some embodiments, the second shell is external to the first shell.

By adopting the scheme, on one hand, the first shell layer is not provided with a weak area, so that the strength of each part is stable, and the first shell layer is used for sealing the battery monomer from the inside. On the other hand, the weak region is easy to damage because the weak region exists on the second shell layer, if the second shell layer is arranged inside the first shell layer, after the weak region is damaged, electrolyte may penetrate between the first shell layer and the second shell layer, the first shell layer further bulges outwards under the impact of high temperature and high pressure inside the battery monomer, the electrolyte enters the interlayer between the second shell layer and the first shell layer, and finally leaks out from the position outside the weak region, so that the emission in the battery monomer cannot be accurately discharged from the pressure leakage region in a directional manner. Therefore, the second shell layer is arranged outside the first shell layer, so that the probability of directional discharge of the discharge in the battery unit from the pressure relief area can be further improved.

In some embodiments, the melting point of the second shell is greater than the melting point of the first shell; or the tensile strength of the second shell layer is greater than that of the first shell layer.

By adopting the scheme, the part of the second shell layer except the weak area is not easy to be damaged, so that after the emission damages the first shell layer, the weak area is damaged before the emission is damaged on the other part of the second shell layer, and the effect of directional emission of the emission from the pressure release area is further achieved.

In some embodiments, the edges of either end of the second shell are positioned inwardly of the edges of the corresponding end of the first shell along the length of the housing.

Through adopting above-mentioned scheme, the length of second shell on casing length direction can not increase the free size of battery, has improved the free energy density of battery, the free equipment of battery of being convenient for, the setting of second shell can not influence being connected of first shell and end cover moreover, makes the free other performances of battery not influenced.

In some embodiments, the second shell is wrapped more than one turn around the surface of the first shell.

Through adopting above-mentioned scheme, at first, the one end that first shell was kept away from to the second shell can be laminated on the second shell for second shell itself forms the comparatively stable reel form of a structure, thereby when battery monomer internal pressure increases, the second shell is difficult to be torn the expansion, and, the number of piles of second shell is more, and the structure of the part except weak area is more firm.

According to a second aspect of the embodiments of the present application, there is provided a battery including a plurality of battery cells according to any one of the first subject matters, wherein a gap is formed between the plurality of battery cells, and a pressure relief area of the battery cell faces the gap.

By adopting the scheme, after the single battery monomer in the battery is subjected to thermal runaway, the generated emissions are discharged from the pressure relief area, and the pressure relief area faces to the gap between the battery monomers, so that the emissions at high temperature and high pressure cannot be immediately discharged to other battery monomers after the pressure relief area is damaged, the time of thermal runaway diffusing to other battery monomers is prolonged, and the use safety of the battery is improved.

According to a third aspect of embodiments of the present application, there is provided an electric device including the battery cell in any of the embodiments of the first subject matter.

By adopting the scheme, the use safety of the electric device is higher.

This application embodiment is through setting up the pressure release district on the free shell of battery for the emission that the free thermal runaway of battery produced can be followed the directional release in pressure release district, and be difficult to release from other positions of casing, when forming the battery with this free assembly of battery, orientation through adjusting the pressure release district, thereby make the emission in the free of battery after the pressure release district actuation can be towards the directional discharge of predetermined safe direction, prevent that the free of battery from releasing internal pressure towards other free of battery or flammable and explosive parts, and then slow down the time of thermal diffusion, improve the safety in utilization of battery.

The foregoing description is only an overview of the technical solutions of the embodiments of the present application, and the embodiments of the present application can be implemented according to the content of the description in order to make the technical means of the embodiments of the present application more clearly understood, and the detailed description of the present application is provided below in order to make the foregoing and other objects, features, and advantages of the embodiments of the present application more clearly understandable.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an automobile according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a battery according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a battery module according to an embodiment of the present application.

Fig. 4 is an exploded view of a battery cell according to an embodiment of the present application.

Fig. 5 is an exploded view of the housing in an embodiment of the present application.

Fig. 6 is a schematic structural diagram of a first type of weak area in an embodiment of the present application.

Fig. 7 is a schematic structural diagram of a second type of weak area in an embodiment of the present application.

Fig. 8 is a schematic structural diagram of a third type of weak area in an embodiment of the present application.

Fig. 9 is a schematic cross-sectional view of a first housing in an embodiment of the present application.

Fig. 10 is a schematic cross-sectional view of a second housing in an embodiment of the present application.

FIG. 11 is a cross-sectional view of a third housing in an embodiment of the present application.

Fig. 12 is a partially enlarged schematic view of a housing according to an embodiment of the present application.

Description of reference numerals: 10. an automobile; 101. a battery; 102. a controller; 103. a motor; 20. a battery module; 21. a first case; 22. a second case; 30. a battery cell; 31. a housing; 32. an electrode assembly; 40. a housing; 401. a first shell layer; 402. a second shell layer; 403. a region of weakness; 404. a pressure relief area; 405. a head end; 406. a tail end; 50. an end cap; 501. and an electrode terminal.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

The terms "comprising" and "having," and any variations thereof, in the description and claims of this application and the description of the drawings are intended to cover, but not to exclude, other elements. The word "a" or "an" does not exclude a plurality.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The following description is given with the directional terms as they are shown in the drawings, and is not intended to limit the specific structure of the battery cell, the battery or the power device of the present application. For example, in the description of the present application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in an orientation or positional relationship indicated based on the orientation or positional relationship shown in the drawings for the convenience of description and simplicity of description only, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered as limiting the present application.

Further, expressions of directions indicated for explaining the operation and configuration of each member of the battery cell, the battery or the electric device of the present embodiment, such as the X direction, the Y direction and the Z direction, are not absolute but relative, and although these indications are appropriate when each member of the battery pack is in the position shown in the drawings, when the position is changed, the directions should be interpreted differently to correspond to the change.

Furthermore, the terms "first," "second," and the like in the description and claims of the present application or in the above-described drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential order, and may explicitly or implicitly include one or more of the features.

In the description of the present application, unless otherwise specified, "plurality" means two or more (including two), and similarly, "plural groups" means two or more (including two).

In the description of the present application, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., "connected" or "connected" of a mechanical structure may refer to a physical connection, e.g., a physical connection may be a fixed connection, e.g., a fixed connection by a fastener, such as a screw, bolt, or other fastener; the physical connection can also be a detachable connection, such as a mutual clamping or clamping connection; the physical connection may also be an integral connection, for example, a connection made by welding, gluing or integrally forming the connection. "connected" or "connected" of circuit structures may mean not only physically connected but also electrically connected or signal-connected, for example, directly connected, i.e., physically connected, or indirectly connected through at least one intervening component, as long as the circuits are in communication, or communication between the interiors of two components; signal connection may refer to signal connection through a medium, such as radio waves, in addition to signal connection through circuitry. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In a device using a battery as a driving energy source, the battery is used as a core component, so that the guarantee of the use safety of the battery is important for guaranteeing the use safety of the whole device, and the thermal runaway of the battery is an important factor threatening the use safety of the battery.

In the use process of the current battery, when one battery cell is subjected to thermal runaway, emissions are generated in the battery cell, the emissions contain substances such as high-temperature smoke (serious people generate open fire) and volatilized high-temperature electrolyte, and the emissions carry a large amount of heat in the emission process, so that the emission process becomes thermal diffusion, especially at the moment when the emissions are just sprayed out of the battery cell, the temperature and pressure of the emissions are extremely high, if the emissions at high temperature and high pressure meet other battery cells in the emission process, thermal runaway of other battery cells is easily caused, and serious people even can cause accidents such as combustion, explosion and the like.

In the use process of the battery in the prior art, the thermal runaway of other battery cells in the battery is caused by the thermal runaway of a single battery cell.

The inventor has found that, through long-term research, the strength difference of each position of the outer shell of the existing battery cell is almost the same, when the thermal runaway of the battery cell occurs, after the temperature and the pressure of the emissions in the battery cell rise to a certain degree, the emissions in the battery cell may be discharged from any position of the shell, when the damaged position is opposite to other battery cells, the emissions rapidly contact other battery cells, and the structure of other battery cells is damaged from the outside, so that the thermal runaway of other battery cells is caused.

In view of this, embodiments of the present application provide a battery cell, a battery and an electric device, in which a pressure relief region is disposed on a housing of the battery cell, so that emissions generated by thermal runaway of the battery cell can be discharged directionally, and thus, the time for thermal runaway to diffuse to other battery cells is prolonged, and the safety of the battery is improved.

The battery cell provided by the embodiment of the present application may be applied to various devices using a battery, such as a mobile phone, a portable device, a notebook computer, a battery car, an electric toy, an electric tool, an electric vehicle, a ship, a spacecraft, and the like, for example, but not limited to, a spacecraft including an airplane, a rocket, a space shuttle, and a spacecraft.

As shown in fig. 1, fig. 1 is a schematic structural diagram of an electric device according to an embodiment of the present application, and the electric device is taken as an example of an automobile 10, where the automobile 10 may be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile may be a pure electric automobile, a hybrid electric automobile, or an extended range automobile. The automobile 10 includes a battery 101, a controller 102, and a motor 103. The battery 101 is used to supply power to the controller 102 and the motor 103 as an operation power source and a driving power source of the automobile 10, for example, the battery 101 is used for a power demand for operation at the start, navigation, and running of the automobile 10. For example, the battery 101 supplies power to the controller 102, the controller 102 controls the battery 101 to supply power to the motor 103, and the motor 103 receives and uses the power of the battery 101 as a driving power source of the automobile 10, instead of or in part replacing fuel or natural gas to provide driving power for the automobile 10.

As shown in fig. 2, in order to enable the battery 101 to achieve a high function to meet the use requirement, the battery 101 may include a plurality of battery modules 20 electrically connected to each other, the battery 101 includes a case including a first case 21, a second case 22 and a plurality of battery modules 20, wherein the first case 21 and the second case 22 are fastened to each other, and the plurality of battery modules 20 are arranged in a space enclosed by the first case 21 and the second case 22. The first case 21 and the second case 22 may be made of aluminum, aluminum alloy, or other metal materials. In some embodiments, the first case 21 and the second case 22 are hermetically connected.

As shown in fig. 3, the battery module 20 may include one or more battery cells 30, and when the battery module 20 includes a plurality of battery cells 30, the plurality of battery cells 30 may be electrically connected in series, in parallel, or in series-parallel to achieve a larger current or voltage, wherein the series-parallel refers to a combination of series connection and parallel connection. In addition, the plurality of battery cells 30 may be arranged according to a predetermined rule, for example, in one embodiment, the plurality of battery cells 30 are placed in the Z-direction vertical direction and arranged in rows in the X-direction and in columns in the Y-direction.

Fig. 4 is a schematic diagram of a partially exploded structure of a battery cell 30 disclosed in an embodiment of the present disclosure, wherein the battery cell 30 may be a secondary battery or a primary battery, such as, but not limited to, a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium ion battery, or a magnesium ion battery. The battery cell 30 may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, and the battery cell 30 is exemplified as a cylinder in this example of the present application.

The battery cell 30 includes a case 31, an electrode assembly 32, and an electrolyte.

The electrode assembly 32 is composed of a positive electrode plate, a negative electrode plate and a separator, and the battery cell 30 mainly depends on metal ions moving between the positive electrode plate and the negative electrode plate to work. The positive pole piece includes anodal mass flow body and anodal active substance layer, and anodal active substance layer coats in anodal mass flow body's surface, and the anodal mass flow body protrusion in the anodal mass flow body that has coated anodal active substance layer of uncoated anodal active substance layer, and the anodal mass flow body that does not coat anodal active substance layer is as anodal utmost point ear. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative pole mass flow body and negative pole active substance layer, and the negative pole active substance layer coats in the surface of negative pole mass flow body, and the negative pole mass flow body protrusion in the negative pole mass flow body of coating the negative pole active substance layer not coating the negative pole active substance layer, and the negative pole mass flow body of not coating the negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not generated by passing large current, the number of the positive pole lugs is multiple and are laminated together, the number of the negative pole lugs is multiple and are laminated together, or the positive pole lugs are connected into a whole in a kneading flat mode, and the negative pole lugs are connected into a whole in a kneading flat mode. The material of the isolation film may be Polypropylene (PP) or Polyethylene (PE).

The case 31 includes a case 40 and an end cap 50, the case 40 is a hollow structure, a receiving cavity is formed inside the case 40, the electrode assembly 32 is located in the receiving cavity, the case 40 has an opening so that the electrode assembly 32 is inserted into the receiving cavity from the opening, and the opening may be located on an end surface of the case 40, for example, the case 40 includes two openings respectively located on two end surfaces of the cylindrical case 40, that is, the two end surfaces of the case 40 do not have end walls to communicate the inside and the outside of the case 40, so that the electrode assembly 32 can be inserted into the case 40 from any one of the openings. The end cap 50 covers the opening of the case 40, and the end cap 50 cooperates with the case 40 to seal the electrode assembly 32 and the electrolyte within the receiving cavity. Optionally, the end cap 50 and the housing 40 are hermetically connected by circumferential welding. The end cap 50 is provided with an electrode terminal 501, and the electrode terminal 501 is used to conduct the electrode assembly 32 to an external circuit.

As shown in fig. 5, fig. 5 is a schematic diagram of an explosion structure of the case, the case 40 includes a first case 401 and a second case 402 along a thickness direction of a case wall, the second case 402 has a weak region 403, so that the case 40 forms a pressure relief region 404 at the weak region 403, and the pressure relief region 404 is configured to be actuated to relieve internal pressure when the internal pressure or temperature of the battery cell 30 reaches a threshold value.

The first shell 401 is cylindrical, and the first shell 401 may be formed by winding or by axially stretching. The first shell 401 may be made of metal such as aluminum or aluminum alloy.

The second shell 402 may be cylindrical or substantially cylindrical, the material of the second shell 402 may be the same as or different from that of the first shell 401, and the second shell 402 serves to reinforce the first shell 401.

Taking the side of the case 40 for accommodating the electrode assembly 32 as the inside and the side far from the electrode assembly 32 as the outside, the relationship between the first case layer 401 and the second case layer 402 in the thickness direction of the case 40 may be that the first case layer 401 is located inside the second case layer 402, or the second case layer 402 is located inside the first case layer 401, which is not limited in this embodiment of the present application.

The connection between the housing 40 and the end cap 50 may be made only through the first shell 401 and the end cap 50, only through the second shell 402 and the end cap 50, or both the first shell 401 and the second shell 402 are connected to the end cap 50. When only the first shell 401 is connected to the end cap 50, the edge of either end of the second shell 402 is positioned inward of the edge of the corresponding end of the first shell 401 along the length of the housing 40 so that the second shell 402 is positioned so as not to interfere with the connection of the first shell 401 to the end cap 50. Similarly, when only the second shell 402 is coupled to the end cap 50, the edge of either end of the first shell 401 is positioned inward of the edge of the corresponding end of the second shell 402 along the length of the housing 40 so that the first shell 401 does not interfere with the coupling of the second shell 402 to the end cap 50. When the first and second shells 401, 402 are both attached to the end cap 50, the edges of the first and second shells 401, 402 at either end are substantially flush along the length of the housing 40.

The longitudinal direction of the housing 40 refers to a direction parallel to the opening of the housing 40, for example, if the opening of the housing 40 faces vertically upward or downward, the longitudinal direction of the housing 40 also faces vertically upward or downward, and of course, the longitudinal direction of the housing 40 is only a general direction and is not strictly parallel to the opening of the housing 40.

The thickness of the case 40 is the sum of the thicknesses of the first case 401 and the second case 402 at corresponding positions, and when the position corresponding to the first case 401 is the weak area 403 on the second case 402, the case 40 is weak at the corresponding position, which is referred to as a pressure relief area 404 of the case 40, at the pressure relief area 404, since the second case 402 has no or weak reinforcing effect on the first case 401, the strength of the case 40 formed by combining the first case 401 and the second case 402 is weaker at the pressure relief area 404 than at other positions, and when the internal pressure or temperature of the battery cell 30 reaches a threshold value in thermal runaway, the pressure relief area 404 is first actuated to relieve the internal pressure of the battery cell 30.

Here, the actuation means that the pressure relief region 404 is activated or activated to a certain state, so that the internal pressure of the battery cell 30 is relieved. The actions generated by the pressure relief region 404 include, but are not limited to: at least a portion of the pressure relief zone 404 ruptures, fractures, is torn or opened, or the like. When the pressure relief region 404 is activated, the high-temperature and high-pressure substances inside the battery cell 30 are discharged as emissions from the activated portion. In this way, the battery cell 30 can be vented under controlled pressure or temperature, thereby avoiding potentially more serious accidents. Emissions from the battery cell 30 as referred to in this application include, but are not limited to: electrolyte, dissolved or split anode and cathode pole pieces, fragments of a separation film, high-temperature and high-pressure gas generated by reaction, flame and the like. The high-temperature, high-pressure effluent is discharged in the direction of the pressure relief area 404 of the battery cell 30, and the power and destructive power of such effluent may be great and may even be sufficient to break through one or more thin-walled structures in that direction.

The threshold value is a value set according to the strength or melting point of the pressure relief region 404, for example, the threshold value may be 800kpa, when the pressure in the battery cell 30 reaches the threshold value, the pressure relief region 404 is activated to relieve the pressure, and for example, the threshold value may be 1000 ℃, when the temperature inside the battery cell 30 reaches the temperature, the pressure relief region 404 is activated to relieve the internal high-temperature exhaust.

By adopting the above scheme, when the internal temperature or pressure of the battery cell 30 reaches the threshold value capable of actuating the pressure relief region 404, the pressure relief region 404 is damaged before other positions of the housing 40, so that the internal temperature or pressure of the battery cell 30 is directionally released from the pressure relief region 404 and is not easy to release from other positions of the housing 40, when the battery cell 30 is assembled to form the battery 101, by adjusting the orientation of the pressure relief region 404, the emissions in the battery cell 30 after the pressure relief region 404 is actuated can be directionally discharged towards a preset safe direction, the components of the locations where the emissions flow through are damaged by the internal pressure of the battery cell 30 being released towards other battery cells 30 or flammable and explosive components, so that the time of heat diffusion is reduced, and the use safety of the battery 101 is improved.

As shown in fig. 6, 7 and 8, fig. 6, 7 and 8 are schematic views of three forms of the area of weakness, respectively, and in some embodiments the area of weakness 403 extends along the length of the housing 40.

In some embodiments, one or more regions of weakness 403 may be provided along the length of the housing 40. As shown in fig. 6, when the weak area 403 is provided in one along the length direction of the case 40, the weak area 403 may penetrate the entire case 40 along the length direction. As shown in fig. 7, the area of weakness 403 may not extend through the housing 40.

As shown in fig. 8, when the weak area 403 is provided in plural in the length direction of the case 40, each weak area 403 extends in the length direction of the case 40 and the plural weak areas 403 may be provided at intervals therebetween.

Since the plurality of battery cells 30 are parallel to each other and stand in the case when the battery 101 is assembled, the battery cells 30 may be adjacent to any one of the battery cells 30 or may form a gap with the battery cells 30 in different directions of the circumference of the case 40 of the same battery cell 30. If the weak region 403 is extended in the circumferential direction of the case 40, one segment of the weak region 403 may face a gap between the battery cell 30 and another battery cell 30, and another segment may face another battery cell 30 during the extension of the weak region 403, so that even if the emission is discharged in a directed manner, the emission may affect the adjacent battery cell 30, and the heat spreading speed may be increased.

By extending the weak region 403 in the length direction of the case 40, the discharge may damage the case 40 of the battery cell 30 in the length direction of the case 40, and thus it is possible to confine the high-temperature and high-pressure discharge in a direction, which may be a gap between the battery cell 30 and the other battery cells 30, thereby preventing the discharge from being discharged toward the other battery cells 30 to damage the same.

In some embodiments, the area of weakness 403 is configured as a notch provided on the second shell 402; or the weakened area 403 is configured as a score provided on the second shell 402; or the thickness of the weak region 403 is less than the thickness of the second shell 402 at a location other than the weak region 403.

As shown in fig. 9, the weak area 403 is configured as a notch formed on the second shell 402, that is, the second shell 402 has no material at the weak area 403, the housing 40 of this structure includes only the first shell 401 in the area of the pressure relief area 404, but does not have the second shell 402, that is, the thickness of the pressure relief area 404 is smaller than that of the area of the housing 40 except the pressure relief area 404, and when the temperature or the air pressure in the battery cell 30 reaches a threshold value, the effluent can be discharged only by breaking the first shell 401 in the pressure relief area 404, so that the effluent can be discharged from the pressure relief area 404 in a more precise and directional manner.

The score is an intermittent or uninterrupted score line formed by intermittently breaking between a portion to be torn and a portion not to be torn by an external force, the broken material is thin and thin but not penetrated, and can be torn by a slight external force, and the original material thickness is remained in the portion of the broken material, so that the score line formed by breaking the material is a score. The score may be formed by a laser-beam punch, laser-marking machine, laser-scribing machine, or laser-cutting machine. When the temperature or air pressure within the battery cell 30 reaches a threshold value, the vent presses the housing 40 from the inside, causing the second shell 402 to tear away from the score, thereby allowing more precise directional venting of the vent from the vent region 404.

When the thickness of the weak region 403 is smaller than the thickness of the second shell 402 at other positions, the strength of the weak region 403 is lower than the strength of the second shell 402 at other positions, so that the strength of the housing 40 at the position corresponding to the weak region 403 is lower to form the pressure relief region 404, and when the battery cell 30 is thermally out of control, high-temperature and high-pressure emissions in the battery cell 30 are easier to damage the housing 40 from the pressure relief region 404, so that the emissions can be discharged from the pressure relief region 404 in a more precise and directional manner.

Wherein the thickness of the weak region 403 can be controlled separately in at least the following two ways. The first is that when the second shell 402 is a single-layer structure, the weak region 403 is formed by processing the single-layer structure to make a local area of the single-layer structure have a thickness smaller than that of other positions, for example, by thinning or grinding the single-layer structure to form the weak region 403, and the thickness of the weak region 403 is smaller than that of other positions of the second shell 402. The second way is that when the second shell 402 is a multi-layer structure, the thickness of the second shell 402 is controlled by controlling the number of layers at a local position of the multi-layer structure, that is, the number of layers at a local area of the multi-layer structure is controlled to be less than the number of layers at other positions, so that the local area forms a weak area 403, and the thickness of the weak area 403 is less than the thickness at other positions of the second shell 402.

By adopting the above-mentioned scheme, when the weak area 403 is a notch, the shell 40 of the pressure relief area 404 only comprises one first shell 401, and high-temperature and high-pressure emissions can be discharged from the pressure relief area 404 only by damaging the first shell 401. When the weakened region 403 is a score, the score is more easily torn by the high temperature, high pressure discharge and is thus more easily vented from the discharge region 404. When the thickness of the weakened region 403 is less than the thickness of the second shell 402 elsewhere, the strength of the weakened region 403 is less than the strength of the second shell 402 elsewhere, and high temperature and pressure emissions are more likely to damage the weakened region 403 of the second shell 402 and thus exit the pressure relief region 404.

In some embodiments, the second shell layer 402 is adhesively attached to the first shell layer 401.

The adhesive for bonding can be a double-sided adhesive tape, a heat-resistant adhesive tape and the like, and compared with a welding connection mode, in an adhesive connection mode, large-area adhesive coating can be performed between the second shell layer 402 and the first shell layer 401, so that the first shell layer 401 and the second shell layer 402 are attached at more positions and are stressed integrally, when the battery monomer 30 expands, all adhesive coating positions of the second shell layer 402 are stressed together, and the second shell layer 402 is stressed uniformly and is not easy to break locally.

In some embodiments, the second shell 402 has an adhesive area that is not less than 50% of the total area of the second shell 402.

The adhesive area refers to the total area of the adjacent second shell layer 402 and the first shell layer 401, and/or the adjacent second shell layer 402 and the second shell layer 402 which are directly connected through an adhesive layer. When the first shell layer 401 has one turn and the second shell layer 402 has one turn or less, the second shell layer 402 is adjacent to the first shell layer 401, and the adhesive area refers to the total area of the second shell layer 402 directly connected to the first shell layer 401 through the adhesive layer. When the first shell layer 401 has one turn and the second shell layer 402 has more than one turn, a partial region of the second shell layer 402 is adjacent to the first shell layer 401 and a partial region is adjacent to the second shell layer 402, and at this time, the adhesive area refers to the sum of the area directly connected between the second shell layer 402 and the first shell layer 401 through the adhesive layer and the area directly connected between the second shell layer 402 and the second shell layer 402 through the adhesive layer.

The total area of the second shell 402 means the area of one side in the thickness direction of the second shell 402.

When it is satisfied that the adhesive area of the second shell layer 402 is not less than 50% of the total area of the second shell layer 402. The bonding surface between the second shell 402 and the first shell 401 or the second shell 402 is large, so that the bonding is firmer, when the battery unit 30 thermally runaway expands, more areas of the second shell 402 are stressed together, and the possibility of local fracture of the second shell 402 is lower.

In summary, the second shell 402 and the first shell 401 are connected by bonding, so that the second shell 402 and the first shell 401 are more easily integrated into a whole, when the internal temperature or air pressure of the battery cell 30 rises, the first shell 401 and the second shell 402 are integrally stressed, and the stress is uniform at each part, so that the part of one layer close to the internal part of the battery cell 30 is prevented from being broken at a position outside the pressure relief area 404 due to no support of the external layer, and further the external layer is broken at a position outside the weak area 403, so that the emission cannot be directionally discharged at the pressure relief area 404.

As shown in fig. 9, 10, and 11, in some embodiments, the second shell 402 is external to the first shell 401.

In this case, the end cap 50 may be better sealed to the housing 40 by being connected to the first shell 401 because the second shell 402 has the weakened area 403 and the first shell 401 has no weakened area 403.

By adopting the above-described scheme, on the one hand, the first shell layer 401 has no weak region 403, so the strength is stable everywhere, and is used for sealing the battery cell 30 from the inside and preventing the electrolyte from leaking. On the other hand, since the weak region 403 exists on the second shell layer 402 and the weak region 403 is easily damaged by the effluent, if the second shell layer 402 is disposed inside the first shell layer 401, after the weak region 403 is damaged by the effluent inside the battery cell 30, the electrolyte may penetrate between the first shell layer 401 and the second shell layer 402, so that the first shell layer 401 bulges further outwards under the impact of high temperature and high pressure inside the battery cell 30, the electrolyte enters the interlayer between the second shell layer 402 and the first shell layer 401 and finally leaks out from a position outside the weak region 403, and thus the effluent inside the battery cell 30 cannot be accurately discharged directionally from the pressure leakage region 404. Therefore, locating the second shell 402 outside the first shell 401 can further increase the probability of the targeted discharge of emissions within the battery cell 30 from the pressure relief zone 404.

In some embodiments, the melting point of the second shell 402 is greater than the melting point of the first shell 401; alternatively, the tensile strength of the second shell layer 402 is greater than that of the first shell layer 401.

By adopting the scheme, the parts of the second shell 402 except the weak areas 403 are not easy to be damaged, so that after the emissions damage the first shell 401, the weak areas 403 are damaged before the emissions are damaged at other places on the second shell 402, thereby further achieving the effect of directional emission of the emissions from the pressure relief area 404.

As shown in fig. 12, in some embodiments, the edges of either end of the second shell 402 are positioned inwardly of the edges of the corresponding end of the first shell 401 along the length of the housing 40.

By adopting the above scheme, the length of the second shell 402 in the length direction of the shell 40 does not increase the size of the single battery 30, the energy density of the single battery 30 is improved, the single battery 30 is convenient to assemble, and the connection between the end cover 50 and the first shell 401 is not affected by the arrangement of the second shell 402, so that other performances of the single battery 30 are not affected.

However, the length of the second shell 402 along the length direction of the casing 40 should not be too small, otherwise, the casing 40 includes only the first shell 401 and not the second shell 402 along the thickness direction thereof near the end, which may result in that the strength of the casing 40 near the end is relatively low, and when the battery cell 30 is thermally runaway, the exhaust inside the battery cell 30 is easily discharged from the position, which may affect the pressure relief effect of the pressure relief area 404.

In order to prevent the above problem from occurring, in some embodiments, the distance between the edge of the end of the second housing layer 402 in the axial direction of the case 40 and the edge of the corresponding end of the first housing layer 401 is less than 0.5mm, thereby preventing the discharge within the battery cell 30 from being discharged from the end of the case 40.

In some embodiments, the second shell 402 surrounds the outer surface of the first shell 401.

Through adopting above-mentioned scheme, the mode that second shell layer 402 encloses and locates first shell layer 401 outer surface is favorable to making second shell layer 402 and first shell layer 401 carry out inseparable laminating, is convenient for assemble second shell layer 402, and in addition, second shell layer 402 can enclose on first shell layer 401 surface and establish half a circle, round or many rings etc. all can control, and the flexibility of assembly is stronger.

As shown in fig. 9, in some embodiments, the second shell layer 402 is wound around the first shell layer 401 less than one turn, in which case a gap is formed between the leading end 405 and the trailing end 406 of the first shell layer 401 in the winding direction, which may serve as the weakened area 403 of the second shell layer 402.

As shown in fig. 10, in some embodiments, the second shell 402 is wound exactly once around the first shell 401, in which case the head end 405 and the tail end 406 of the second shell 402 in the winding direction are exactly connected, and at this time, the second shell 402 can be fixed to the first shell 401, and the head end 405 and the tail end 406 of the second shell 402 can also be fixed, so that the second shell 402 has a more stable structure and is not easily loosened by the expansion force. In this case, the force and thickness are the same at all positions of the second shell 402, and the weak area 403 may be disposed at any position on the second shell 402.

As shown in fig. 11, in some embodiments, the second shell layer 402 is wrapped around the first shell layer 401 more than one turn.

In this embodiment, the number of turns of the second shell layer 402 wound on the first shell layer 401 may be an integer number of turns, i.e. the head end 405 and the tail end 406 of the second shell layer 402 in the winding direction are located in the same radial direction of the shell 40, for example, 2 turns, 3 turns, etc., and the weak area 403 may be disposed at any position of the second shell layer 402; the number of turns of the second shell layer 402 wound around the first shell layer 401 may not be an integer, for example, as shown in fig. 11, the number of turns of the second shell layer 402 wound around the surface of the first shell layer 401 is more than one and less than two, and in this case, the weakened region 403 is provided in a region of the second shell layer 402 where the number of turns is small, so as to be rapidly damaged by the emissions.

Through adopting above-mentioned technical scheme, the number of piles of second shell 402 is more, and the structure is more firm, and second shell 402 along the ascending tail end 406 of coiling direction can with second shell 402 fixed surface, and the stationary plane is bigger, is difficult to tear the expansion under the effect of inflation power.

By adopting the above scheme, firstly, one end of the second shell layer 402 far away from the first shell layer 401 can be attached to the second shell layer 402, so that the second shell layer 402 itself forms a roll shape with a stable structure, and thus, when the internal pressure of the battery cell 30 is increased, the second shell layer 402 is not easily torn and unfolded, and the number of layers of the second shell layer 402 is large, and the structure of the part except the weak area 403 is firmer.

According to a second aspect of the embodiments of the present application, there is provided a battery 101, comprising a plurality of battery cells 30 according to any of the above embodiments, wherein a gap is formed between the plurality of battery cells 30, and the pressure relief region 404 of the battery cell 30 faces the gap.

By adopting the above scheme, after thermal runaway occurs in a single battery cell 30 in the battery 101, the generated emissions are discharged from the pressure relief area 404, and the pressure relief area 404 faces the gap between the battery cells 30, so that the high-temperature and high-pressure emissions are not discharged to other battery cells 30 immediately after the pressure relief area 404 is damaged, thereby prolonging the time for the thermal runaway to diffuse to other battery cells 30 and improving the use safety of the battery 101.

According to a third aspect of the embodiments of the present application, there is provided an electric device including the battery cell 30 in any of the embodiments of the above-mentioned subject matter.

By adopting the scheme, the use safety of the electric device is higher.

In summary, in the embodiment of the present application, the pressure relief area 404 is disposed on the outer casing 31 of the battery cell 30, so that the emissions generated by thermal runaway of the battery cell 30 can be discharged from the pressure relief area 404 in a directional manner, and are not easy to discharge from other positions of the casing 40, when the battery cell 30 is assembled to form the battery 101, by adjusting the orientation of the pressure relief area 404, the emissions in the battery cell 30 after the pressure relief area 404 is activated can be discharged in a directional manner toward a predetermined safe direction, thereby preventing the battery cell 30 from discharging internal pressure toward other battery cells 30 or flammable and explosive components, further slowing down the time of thermal diffusion, and improving the safety of the battery 101.

Those of skill in the art will understand that while some embodiments herein include certain features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims (10)

1. A battery cell, comprising:

a housing including a first shell and a second shell along a thickness direction of a housing wall of the housing, the second shell having a weakened area such that the housing forms a pressure relief area at the weakened area, the pressure relief area configured to actuate to relieve an internal pressure or temperature of a battery cell when the internal pressure or temperature reaches a threshold value.

2. The battery cell as recited in claim 1 wherein the weakened area extends along a length of the housing.

3. The battery cell as recited in claim 1 or 2 wherein the weakened area is configured as a notch provided on the second shell layer;

or the weak area is configured as a score on the second shell layer;

or the thickness of the weak area is smaller than that of the position outside the weak area of the second shell layer.

4. The battery cell as recited in claim 1 or 2 wherein the second shell layer is adhesively attached to the first shell layer.

5. The battery cell according to claim 1 or 2, wherein the second shell layer is located outside the first shell layer.

6. The battery cell as recited in claim 5 wherein the second shell layer has a melting point greater than the melting point of the first shell layer;

or the tensile strength of the second shell layer is greater than that of the first shell layer.

7. The battery cell as recited in claim 1, wherein an edge of either end of the second housing layer is positioned inward of an edge of a corresponding end of the first housing layer along a length of the housing.

8. The battery cell as recited in claim 5 wherein the second shell layer is wound around the first shell layer more than one turn.

9. A battery comprising a plurality of cells according to any one of claims 1-8, a plurality of said cells defining a void therebetween, said pressure relief region of said cells being oriented toward said void.

10. An electric device comprising the battery cell according to any one of claims 1 to 8.

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