Battery, pressure control unit, battery pack, electrical device and energy storage device

Abstract

A battery, a pressure control unit, a battery pack, an electrical device and an energy storage device. The battery comprises a case assembly, at least one battery cell and at least one pressure control unit. The battery cell is accommodated in the case assembly, the battery cell comprising electrode assemblies stacked in a first direction. The pressure control unit comprises a fluid pouch, an accommodating cavity being formed in the fluid pouch; a fluid medium is accommodated in the accommodating cavity, such that the fluid pouch can contract or expand through flow of the fluid medium, thereby applying acting force to the battery cell by means of fluid pressure generated by the fluid medium. The pressure control unit applies acting force to the battery cell at least in an expanded state of the battery cell, so as to control the surface stress of the expanded battery cell.

Description

Batteries, pressure control units, battery packs, power consumption devices and energy storage devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on Chinese patent application number 202410254514.3, application date March 6, 2024, and invention name “Battery, pressure control unit, battery pack, electrical device and energy storage device”, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated into the present disclosure as a reference. Technical Field

[0003] The present disclosure relates to the field of battery technology, and in particular to a battery, a pressure control unit, a battery pack, an electrical device, and an energy storage device. Background Art

[0004] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in energy storage fields.

[0005] In batteries, cells can expand during charge and discharge cycles. If excessive force is applied between cells due to this expansion, the cells can be squeezed and stress concentration can occur, negatively impacting the battery's cycle life and performance. Therefore, mitigating the risks associated with cell expansion is a key research topic in the industry.

[0006] Summary of the Invention

[0007] To solve the above technical problems, the present disclosure provides a battery, a pressure control unit, a battery pack, an electric device, and an energy storage device capable of controlling the stress on the surface of a swollen battery cell.

[0008] The present disclosure is achieved through the following technical solutions.

[0009] A first aspect of the present disclosure provides a battery, comprising: a shell assembly; at least one battery cell accommodated in the shell assembly, the battery cell comprising an electrode assembly stacked along a first direction; and at least one pressure control unit, the pressure control unit comprising a fluid sac, a accommodating cavity formed inside the fluid sac, the accommodating cavity accommodating a fluid medium, the fluid sac being capable of contracting or expanding due to the flow of the fluid medium, thereby applying a force to the battery cell through the fluid pressure generated by the fluid medium; wherein the pressure control unit applies the force to the battery cell, at least when the battery cell is in an expanded state, to control the stress on the surface of the expanded battery cell.

[0010] Since the battery includes a pressure control unit, when the battery cell expands, it will apply a force to the pressure control unit, and the pressure control unit will apply a reaction force to the expanded battery cell, thereby reducing the degree of expansion of the battery cell and reducing the risks caused by expansion, which is conducive to improving the cycle life of the battery.

[0011] Furthermore, because the pressure control unit includes a fluid bladder, the interior of the fluid bladder also forms a receiving cavity that contains a fluid medium, and the fluid bladder can contract or expand due to the flow of the fluid medium. Therefore, the fluid bladder can adjust the pressure exerted by the fluid in the receiving cavity on the bladder wall according to the degree of expansion of the battery cell, applying an appropriate expansion restraint force to the battery cell and providing appropriate expansion space for the battery cell. This controls the stress on the surface of the expanding battery cell, allowing the expansion force of the battery cell to be evenly released, reducing the possibility of free expansion of the battery cell, and further making the force on the surface of the battery cell along the stacking direction of the electrode assembly more uniform, reducing the polarization accumulation of the battery cell, and thus improving battery performance.

[0012] In some embodiments, the battery cells include surfaces facing each other along the first direction, and at least in a state where the battery cells are expanded, an average stress in the same surface of the same battery cell is in a range of 0.1 MPa to 2 MPa.

[0013] Therefore, the expansion restraint force applied to the battery cell by the pressure control unit can control the average stress of the surfaces of the battery cell facing each other along the first direction within an appropriate range. In this way, the average stress in the same surface can always be maintained within an appropriate range, which is beneficial to improving the cycle life of the battery cell and thus improving the performance of the battery.

[0014] In some embodiments, for the same surface of the same battery cell, at the same time, a value of the minimum stress calculated per unit area divided by the maximum stress calculated per unit area is greater than 50%.

[0015] As a result, the force on the surface of the battery cell can be made more uniform, reducing the possibility of stress concentration, so that the battery cell has a good stress environment during the cycle, thereby reducing the possibility of lithium deposition in the battery cell, improving battery performance, and extending the battery life.

[0016] In some embodiments, the maximum pressure that the pressure control unit can apply is in the range of 200N to 4000N.

[0017] As a result, the pressure control unit can apply a significant expansion restraining force to the battery cell and control this force within an appropriate range, effectively counteracting the expansion force of the battery cell. Even in the presence of significant expansion force, the average stress on the surface (e.g., the large surface) of the battery cell can be maintained within an appropriate range. Furthermore, the maximum pressure that the pressure control unit can apply is relatively high, making it less likely that elastic failure, resulting in a failure to rebound and thus a loss of appropriate expansion restraining force on the battery cell, will occur.

[0018] In some embodiments, the fluid sac includes an inlet and an outlet, each of which is in communication with the accommodating chamber. The inlet is configured to allow the fluid medium to flow into the accommodating chamber from the outside, and the outlet is configured to allow the fluid medium to flow out of the accommodating chamber. The fluid sac can expand or contract by the inflow or outflow of the fluid medium.

[0019] Since the fluid sac includes an inlet and an outlet, and the fluid medium can flow into the accommodating cavity or flow out of the accommodating cavity through the inlet and the outlet respectively, an appropriate amount of fluid medium can flow into or out of the accommodating cavity according to the expansion degree of the battery cell. The different pressures generated by different amounts of fluid medium can adjust the force applied to the surface of the battery cell, thereby limiting the expansion of the battery cell while providing a suitable expansion space for the battery cell, reducing the possibility of stress concentration, and maintaining the structural stability of the battery.

[0020] In some embodiments, the battery also includes a top cover assembly, which is located on one side of the shell assembly along the second direction, and the inlet and the outlet are arranged toward the other side of the second direction opposite to the top cover assembly; the second direction is perpendicular to the first direction.

[0021] The inlet and outlet of the fluid sac need to extend out of the shell assembly to communicate with the external fluid medium supply device. Therefore, arranging the inlet and outlet on the other side of the second direction opposite to the top cover assembly can facilitate the installation of the top cover assembly. The inlet and outlet will not affect the connection between the battery cell and the connector of the top cover assembly, and the top cover assembly does not need to reserve additional holes for the inlet and outlet to pass through, thereby reducing the assembly difficulty and production cost.

[0022] In some embodiments, the fluid bladder further comprises at least one baffle, which is located in the accommodating cavity and is used to separate the accommodating cavity into at least two spaced areas, and the spaced areas are connected to form a tortuous fluid medium flow channel.

[0023] As a result, the fluid medium in the accommodating cavity can flow along the curved fluid medium flow channel, which can not only reduce the expansion of the battery cell, but also play a certain cooling role on the surface of the battery cell, remove the heat of the battery cell, realize heat exchange, and provide good temperature conditions for the battery, which is conducive to ensuring the stability of battery performance and reducing the risk of thermal runaway. In addition, there is no need to set up a separate cooling plate or other heat exchange structure in the battery shell assembly, which is conducive to reducing the number of parts, reducing production costs, and improving the space utilization inside the battery.

[0024] In some embodiments, there are multiple baffles, and the multiple baffles extend along the second direction and are spaced apart and arranged in parallel along the third direction; wherein the first direction, the second direction and the third direction are perpendicular to each other.

[0025] This allows the fluid medium to flow through a longer path, allowing it to flow through as much of the battery cell surface as possible within the accommodating cavity, resulting in better heat dissipation. Furthermore, the parallel arrangement of multiple baffles allows the sizes of the spaced areas separated by the baffles to be more uniform, allowing the fluid medium to flow through these uniformly spaced areas and dissipate heat evenly from the battery cells.

[0026] In some embodiments, the fluid sac includes a top wall, a bottom wall and multiple side walls connecting the top wall and the bottom wall, and the top wall, the bottom wall and the multiple side walls define the accommodating cavity; the inlet and the outlet are arranged on the bottom wall; one end of each baffle is connected to the inner wall surface of the top wall or the bottom wall, and the other end is suspended.

[0027] Thus, the suspended end of the baffle can be connected to multiple interval areas separated by the baffle, making the flow path of the fluid medium longer without affecting the flow of the fluid medium, and better dissipating heat for the battery cells.

[0028] In some embodiments, along the third direction, adjacent baffles extend in opposite directions along the first direction.

[0029] Thus, a bent fluid medium flow channel can be formed with a simple structure, so that the fluid medium can dissipate heat from the battery cells more fully and evenly.

[0030] In some embodiments, along the third direction, the baffle closest to the inlet extends along the second direction from the inner wall surface of the bottom wall toward the inner wall surface of the top wall; and / or along the third direction, the baffle closest to the outlet extends along the second direction from the inner wall surface of the bottom wall toward the inner wall surface of the top wall.

[0031] Therefore, when the fluid medium flows into the containing cavity of the fluid bag through the inlet, it cannot flow directly to the outflow outlet along the third direction, but needs to bypass the baffle and flow through the interval area defined by the baffle before flowing to the outflow outlet, thereby extending the flow path of the fluid medium, so that the fluid medium can fully and evenly dissipate heat from the battery cell.

[0032] In some embodiments, the baffle is sealed against inner wall surfaces of the two side walls that are arranged opposite to each other along the third direction.

[0033] As a result, the fluid medium cannot penetrate the baffle when flowing and can only flow along the prescribed curved fluid medium flow channel, thereby better dissipating heat from the battery cells.

[0034] In some embodiments, the fluid bladder is made of an elastic material.

[0035] The elastic material has good elasticity, so it can expand or contract well through the flow of fluid medium, so that the fluid sac can be compressed and produce elastic deformation along the direction of the expansion force of the battery cell after being subjected to the expansion force released by the battery cell, and can rebound after the expansion force of the battery cell is reduced, thereby being able to adapt to the different expansion forms of the battery cell, so that the fluid sac can always apply appropriate force to the surface of the battery cell along the first direction, while reducing the expansion of the battery cell, providing the battery cell with appropriate expansion space, making the stress on the surface of the battery cell along the first direction more uniform, reducing the possibility of stress concentration in the battery cell, and effectively improving the performance of the battery.

[0036] In some embodiments, the elastic material comprises elastic rubber.

[0037] Elastic rubber has good elasticity and is easy to shape, which can effectively reduce processing costs. In addition, elastic rubber has good wear resistance and aging resistance, which can improve the performance of the fluid sac.

[0038] In some embodiments, in each of the pressure control units, within the same projection area perpendicular to the first direction, a projection area of ​​the fluid sac is larger than a projection area of ​​the electrode assembly within the battery cell.

[0039] As a result, the fluid sac can more effectively restrain the expansion of the battery cell, reducing the possibility of adverse conditions such as wrinkling of the electrode assembly's pole pieces due to the free expansion of the battery cell, thereby maintaining the battery's cycle life and good performance.

[0040] In some embodiments, along the first direction, the pressure control unit is disposed adjacent to at least one of the surfaces of the battery cells facing the first direction.

[0041] Thus, the pressure control unit can apply a restraining force to the surface of the battery cell facing the first direction at least when the battery cell is in an expanded state, thereby controlling the expansion degree of the battery cell.

[0042] In some embodiments, there are multiple battery cells, and the multiple battery cells are arranged along the first direction; the pressure control unit is arranged between adjacent battery cells, and / or between the battery cells and the inner wall of the shell assembly adjacent to the battery cells.

[0043] As a result, a pressure control unit can simultaneously apply forces to adjacent battery cells, and can also apply appropriate forces to the surfaces of battery cells adjacent to the housing assembly facing the first direction, thereby helping to provide appropriate expansion restraint forces for the battery cells and improving battery performance. Moreover, by allowing adjacent battery cells to share a pressure control unit, it helps to reduce the number of components. Since the pressure control unit can be arranged between the inner wall of the housing assembly and the battery cells adjacent to the inner wall, even the surface of the battery cells adjacent to the inner wall can be subjected to expansion restraint forces. It can be seen that the large surface of each battery cell housed in the housing assembly can be expansion-restrained and pressure-controlled.

[0044] In some embodiments, the pressure control unit is arranged between every two adjacent battery cells; and / or at least two battery cells form a battery cell group, and the pressure control unit is arranged between two battery cell groups; and / or the pressure control unit is arranged between the battery cell group and the battery cell adjacent to the battery cell group.

[0045] Thus, the pressure control unit can be arranged at different positions in the housing assembly according to different conditions of the battery cells, so that a force can be applied to multiple battery cells at the same time, thereby simultaneously controlling the expansion degree of the multiple battery cells.

[0046] In some embodiments, the battery cell comprises a soft-pack battery cell or a square-shell battery cell.

[0047] Soft-pack battery cells are more prone to expansion during the charge and discharge process. Therefore, the provision of a pressure control unit can effectively reduce the expansion of soft-pack battery cells, thereby reducing the occurrence of adverse phenomena such as lithium deposition caused by excessive expansion of soft-pack battery cells, and improving the battery's charge and discharge cycle life and performance. Prismatic battery cells also expand during the charge and discharge process. The pressure control unit can also apply force to the square-shell battery cells to control the degree of expansion.

[0048] A second aspect of the present disclosure provides a pressure control unit, which is used for a battery, the battery comprising at least one battery cell, the battery cell comprising an electrode assembly stacked along a first direction, the battery cell comprising surfaces facing each other along the first direction; the pressure control unit comprising a fluid sac, a receiving cavity formed inside the fluid sac, the receiving cavity containing a fluid medium, the fluid sac being capable of contracting or expanding by the flow of the fluid medium, thereby applying the force to the battery cell through the fluid pressure generated by the fluid medium; wherein the pressure control unit is configured to apply a force to the battery cell at least when the battery cell is expanded to control the stress on the surface of the expanded battery cell.

[0049] The pressure control unit can exert force on the battery cell when the battery cell is expanded, control the stress on the surface of the battery cell within an appropriate range, thereby reducing the expansion of the battery cell. The pressure control unit constructed as a fluid sac can also adjust the degree of contraction or expansion according to the degree of expansion of the battery cell, providing a suitable expansion space for the battery cell, so that the expansion force of the battery cell can be released evenly, reducing the polarization accumulation of the battery cell, and helping to improve the performance and charge and discharge cycle life of the battery.

[0050] In some embodiments, the maximum pressure that the pressure control unit can apply is in the range of 200N to 4000N.

[0051] As a result, the pressure control unit can exert a significant expansion-restraining force on the battery cell and control this force within an appropriate range, effectively counteracting the expansion force of the battery cell. Even in the presence of significant expansion force, the average stress on the battery cell surface can be maintained within an appropriate range. Furthermore, the maximum pressure that the pressure control unit can exert is relatively high, making it less likely that elastic failure, resulting in a failure to rebound and thus a loss of appropriate expansion-restraining force, will occur on the battery cell.

[0052] In some embodiments, the fluid sac includes an inlet and an outlet, and the inlet and the outlet are respectively connected to the accommodating cavity, the inlet is used to allow the fluid medium to flow into the accommodating cavity from the outside, and the outlet is used to allow the fluid medium to flow out of the accommodating cavity; the fluid sac can expand or contract by the inflow or outflow of the fluid medium.

[0053] In this way, the fluid medium can flow into or out of the accommodating cavity according to the expansion degree of the battery cell, and the different pressures generated by different amounts of fluid medium can be used to adjust the force applied to the surface of the battery cell. This not only limits the expansion of the battery cell, but also reserves appropriate expansion space for the battery cell, so that the stress on the surface of the battery cell is uniform.

[0054] In addition, the flow circulation of the fluid medium inside the accommodating cavity can be achieved through the inlet and outlet, thereby reducing the expansion of the battery cell while taking away the heat of the battery cell to achieve heat exchange. In this way, pressure management and temperature management are combined into one, without the need to set up additional heat exchange structures, effectively saving space and reducing weight.

[0055] In some embodiments, the fluid bladder further comprises at least one baffle, which is located in the accommodating cavity and is used to separate the accommodating cavity into at least two spaced areas, and the spaced areas are connected to form a tortuous fluid medium flow channel.

[0056] In this way, the flow path of the fluid medium in the accommodating cavity can be extended, so that the fluid medium can flow through more parts of the accommodating cavity through the bent fluid medium flow channel, thereby increasing the heat dissipation area of ​​the surface of the battery cell and further improving the heat dissipation efficiency.

[0057] A third aspect of the present disclosure provides a battery pack, comprising: a case; and at least one battery according to the first aspect of the present disclosure, the battery being accommodated in the case.

[0058] Since the battery pack provided by the embodiment of the present disclosure uses battery cells equipped with a pressure control unit, the average stress of the large surface of the battery cell is within an appropriate range and has good uniformity, and the risk of stress concentration is reduced. Therefore, the risk of the battery pack having a reduced charge and discharge cycle life due to expansion of the battery cell is reduced.

[0059] A fourth aspect of the present disclosure provides an electrical device, which includes the battery described in the first aspect of the present disclosure or the battery pack described in the third aspect of the present disclosure for providing electrical energy.

[0060] Since the electric device of the embodiment of the present disclosure adopts the battery pack with good performance as described above, the time spent on maintenance is reduced, and the risk of failure of the electric device due to battery pack failure is reduced.

[0061] A fifth aspect of the present disclosure provides an energy storage device, which includes the battery described in the first aspect of the present disclosure or the battery pack described in the third aspect of the present disclosure for storing or providing electrical energy.

[0062] Since the energy storage device of the embodiment of the present disclosure adopts the battery pack with good performance as described above, the time spent on maintenance is reduced, and the risk of failure of the energy storage device due to battery pack failure is reduced.

[0063] Effects of the Invention

[0064] Through the present disclosure, it is possible to control the stress on the surface of the expanded battery cell, thereby reducing the expansion of the battery cell and providing a suitable expansion space for the battery cell, so that the expansion force of the battery cell can be released evenly, reducing the polarization accumulation of the battery cell, and helping to improve the performance and charge and discharge cycle life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present disclosure. The same reference numerals are used throughout the drawings to denote the same components. In the drawings:

[0066] FIG1 is a schematic structural diagram of a vehicle provided by some embodiments of the present disclosure;

[0067] FIG2 is a perspective exploded schematic diagram of a battery pack provided by some embodiments of the present disclosure;

[0068] FIG3 is a partial exploded perspective view of a battery provided by some embodiments of the present disclosure;

[0069] FIG4 is a partially exploded perspective view of another battery provided by some embodiments of the present disclosure;

[0070] FIG5 is a schematic diagram of the three-dimensional structure of a pressure control unit provided in some embodiments of the present disclosure;

[0071] FIG6 is a cross-sectional view of a pressure control unit provided by some embodiments of the present disclosure, wherein the dotted line represents the flow path of the fluid medium;

[0072] FIG7 is another cross-sectional view of a pressure control unit provided by some embodiments of the present disclosure;

[0073] FIG8 is a schematic diagram of the three-dimensional structure of a shell assembly and a top cover assembly of a battery provided in some embodiments of the present disclosure.

[0074] Description of Reference Numerals

[0075] 1-fluid sac; 11-containing chamber; 111-spacer area; 12-top wall; 13-bottom wall; 14-side wall; 2-ear; 3-inflow port; 4-outflow port; 5-baffle; 10-battery cell; 20-pressure control unit; 30-housing assembly; 40-top cover assembly; 100-battery; 200-controller; 300-motor; 400-battery pack; 401-casing; 401a-cover; 401b-bottom plate; 1000-vehicle; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0076] The following embodiments of the technical solution of the present disclosure are described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present disclosure and are therefore only examples and are not intended to limit the scope of protection of the present disclosure.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this disclosure; the terms "including" and "having" and any variations thereof in this disclosure are intended to cover non-exclusive inclusions.

[0078] In the description of the embodiments of the present disclosure, technical terms such as "first," "second," "third," "fourth," and "fifth" are used solely to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0079] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0080] In the description of the embodiments of the present disclosure, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0081] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present disclosure.

[0082] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0083] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and can be direct contact, contact through an intermediate medium layer, contact with essentially no interaction force between the two contacting parties, or contact with interaction force between the two contacting parties.

[0084] Hereinafter, the present disclosure will be described in detail.

[0085] Currently, new energy batteries are increasingly being used in everyday life and industry. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in a variety of fields such as aerospace. As the application of power batteries continues to expand, market demand is also growing.

[0086] During the charge and discharge cycle of a battery cell, the electrode components and electrolyte inside the battery cell will undergo chemical reactions, resulting in expansion of the negative electrode or generation of gas, which will cause the battery cell to expand.

[0087] Especially for lithium metal batteries using lithium metal as the negative electrode, the negative electrode expands in volume during cycling, which causes the electrode thickness to increase continuously, leading to battery bulging and even battery failure. This consequence of volume expansion is particularly significant in soft-pack batteries using flexible materials as the battery casing, as rigid structural components cannot be used to limit expansion.

[0088] There is also the problem of battery cells bulging and expanding in square shell batteries.

[0089] In related technologies, to avoid structural interference between adjacent battery cells due to bulging and expansion, which could lead to further negative effects, a certain gap is reserved between adjacent battery cells during the battery assembly process to provide expansion space for the battery cells. However, when a certain gap is reserved between adjacent battery cells, the battery cells can expand freely due to lack of external constraints. This can cause the electrode sheets in the electrode assembly to wrinkle, leading to adverse conditions such as lithium deposition, resulting in deterioration of battery cycle performance and a significant reduction in battery life.

[0090] In the related art, there is also a solution that provides a certain expansion buffer for the battery cells by placing a buffer pad between adjacent battery cells. The buffer pad is made of foam with a certain degree of compressibility. When the battery cell expands, the buffer pad is squeezed to deform. The buffer pad limits the expansion of the battery cell through its own elastic rebound force after deformation. However, the buffer pad is limited by its own deformation capacity. When the expansion force of the battery cell is too large, it will be difficult for the buffer pad to continue to deform. Moreover, after being compressed multiple times, the buffer pad will cause permanent compression deformation and will no longer be able to provide expansion limiting effect for the battery cell. In other words, a buffer pad of appropriate thickness, such as foam, cannot provide a sufficiently large restraining force for the expansion force of the battery cell, and cannot effectively manage the pressure of the battery cell.

[0091] Especially for batteries used in fields such as aerospace, due to their unique application environment, the performance of the battery is required to be adapted to the application scenario. Taking aircraft as an example, during takeoff or landing, the aircraft sometimes draws high discharge current from the battery. In this case, the battery will release a large amount of heat, and there is a possibility that the battery will swell more seriously. In addition, when the aircraft flies at high altitudes, the reduction in air pressure and air density will also aggravate the expansion of the battery. Therefore, it is necessary to apply greater expansion restraint force to the battery cells.

[0092] Therefore, it is desirable to apply appropriate expansion restraining force to the expanded battery cells so that the surface of the expanded battery cells has appropriate and relatively uniform stress and can provide appropriate expansion space for the battery cells. In other words, it is desirable to provide a battery capable of controlling the stress on the surface of the expanded battery cells, a pressure control unit applied to such a battery, and an electrical device and an energy storage device including such a battery.

[0093] The present disclosure addresses the problems existing in the above-mentioned related technologies and proposes a battery. The battery includes a shell assembly, at least one battery cell and at least one pressure control unit. The battery cell is accommodated in the shell assembly, and the battery cell includes an electrode assembly stacked along a first direction. The pressure control unit includes a fluid sac, and a receiving cavity is formed inside the fluid sac. The fluid sac can shrink or expand due to the flow of a fluid medium, thereby applying a force to the battery cell through the fluid pressure generated by the fluid medium. The pressure control unit applies a force to the battery cell at least when the battery cell is in an expanded state, so as to control the stress on the surface of the expanded battery cell.

[0094] Since the battery includes a pressure control unit, when the battery cell expands, it will apply a force to the pressure control unit, and when the pressure control unit is compressed, it will apply a reaction force to the battery cell, thereby reducing the degree of expansion of the battery cell and the risks caused by expansion, which is conducive to improving the cycle life of the battery.

[0095] In addition, because the pressure control unit includes a fluid bladder, a chamber is formed inside the fluid bladder, which contains a fluid medium and can contract or expand due to the flow of the fluid medium. Therefore, the fluid bladder can adjust the pressure exerted by the fluid in the chamber on the bladder wall according to the degree of expansion of the battery cell, exerting an appropriate force (expansion restraining force) on the battery cell, providing the battery cell with appropriate expansion space, thereby controlling the stress on the surface of the expanding battery cell, allowing the expansion force of the battery cell to be evenly released, reducing the possibility of free expansion of the battery cell, and further making the force on the surface of the battery cell along the stacking direction of the electrode assembly more uniform, reducing the polarization accumulation of the battery cell, and beneficially improving battery performance.

[0096] The battery provided in the embodiments of the present disclosure can be used, but is not limited to, in energy storage power supply systems, electrical devices such as vehicles, ships or aircraft, as well as energy storage devices such as energy storage containers and energy storage cabinets.

[0097] The batteries provided in the embodiments of the present disclosure can also be grouped together to form a battery pack. The battery pack can also be used, but is not limited to, in energy storage power systems, electrical devices such as vehicles, ships, or aircraft, as well as energy storage devices such as energy storage containers and energy storage cabinets.

[0098] The embodiments of the present disclosure provide an electrical device including the above-mentioned battery or battery pack for providing electrical energy, and the electrical device includes, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0099] In the following embodiments, for the convenience of description, the electric device of one embodiment of the present disclosure is taken as an example of a vehicle 1000. The following description is made with reference to the accompanying drawings.

[0100] FIG1 is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present disclosure. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. As shown in FIG1 , a battery 100 is provided inside the vehicle 1000. The battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0101] In some embodiments of the present disclosure, the battery 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0102] Figure 2 is a perspective exploded schematic diagram of a battery pack 400 provided in an embodiment of the present disclosure. As shown in Figure 2, the battery pack 400 includes a housing 401 and at least one battery 100. The housing 401 includes a cover 401a and a bottom plate 401b. The cover 401a covers the bottom plate 401b, thereby forming a storage space for the battery 100 between the bottom plate 401b and the cover 401a.

[0103] In the battery pack 400, there can be multiple batteries 100, and the multiple batteries 100 can be connected in series, in parallel, or in a mixed connection. Mixed connection means that the multiple batteries 100 are connected both in series and in parallel. The multiple batteries 100 can be directly connected in series, in parallel, or in a mixed connection, and then the whole composed of multiple batteries 100 is placed in the storage space formed by the bottom plate 401b and the cover 401a. Of course, the battery 100 can also be a battery module formed by first connecting multiple battery cells 10 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and then accommodated in the storage space formed by the bottom plate 401b and the cover 401a. The battery pack 400 may also include other structures. For example, the battery pack 400 may also include a busbar component for achieving electrical connection between the multiple batteries 100.

[0104] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to FIG. 3 to FIG. 7 .

[0105] Figure 3 is a schematic diagram of a partial three-dimensional decomposition of a battery provided in some embodiments of the present disclosure. Figure 4 is a schematic diagram of a partial three-dimensional decomposition of another battery provided in some embodiments of the present disclosure. Figure 5 is a schematic diagram of the three-dimensional structure of a pressure control unit provided in some embodiments of the present disclosure. Figure 6 is a cross-sectional view of the pressure control unit provided in some embodiments of the present disclosure, wherein the dotted line represents the flow path of the fluid medium. Figure 7 is another cross-sectional view of the pressure control unit provided in some embodiments of the present disclosure. Figure 8 is a schematic diagram of the three-dimensional structure of the shell assembly and top cover assembly of the battery provided in some embodiments of the present disclosure.

[0106] In some embodiments of the present disclosure, for ease of description, a first direction, a second direction, and a third direction are defined, and the first direction, the second direction, and the third direction are perpendicular to each other. However, those skilled in the art should understand that the embodiments of the present disclosure are not limited to the case where the three directions are perpendicular to each other. For ease of description, as shown by the arrows in Figures 3 to 8, the direction indicated by arrow X is the first direction, the direction indicated by arrow Y is the second direction, and the direction indicated by arrow Z is the third direction.

[0107] As shown in Figures 3, 4 and 8, the first aspect of the present disclosure provides a battery 100. The battery 100 includes a shell assembly 30, at least one battery cell 10 and at least one pressure control unit 20. The battery cell 10 is accommodated in the shell assembly 30, and the battery cell 10 includes an electrode assembly stacked along a first direction. The pressure control unit 20 includes a fluid capsule 1, and a receiving cavity 11 is formed inside the fluid capsule 1. The receiving cavity 11 contains a fluid medium. The fluid capsule 1 can shrink or expand due to the flow of the fluid medium, thereby applying a force to the battery cell through the fluid pressure generated by the fluid medium. In particular, the pressure control unit 20 applies a force to the battery cell 10 at least when the battery cell 10 is in an expanded state, so as to control the stress on the surface of the expanded battery cell 10.

[0108] The housing assembly 30 is an outer protective housing of the battery 100 .

[0109] For example, the housing assembly 30 may be formed by bending and welding a metal plate, thereby having good pressure bearing capacity and being able to better protect the internal battery cells 10 .

[0110] As another example, the housing assembly 30 can be integrally formed by injection molding of a plastic material. While meeting basic strength requirements, the plastic material itself is lighter in weight and has good insulation performance, and no additional insulation layer needs to be installed.

[0111] The battery 100 also includes a top cover assembly 40, which is located on one side of the shell assembly 30 along the second direction and covers the shell assembly 30, and is used to separate the internal environment of the battery 100 from the external environment, thereby further protecting the battery cell 10 contained in the shell assembly 30, and can also reduce the possibility of the battery cell 10 in the shell assembly 30 detaching from the shell assembly 30.

[0112] The battery cell 10 refers to a basic unit that can realize mutual conversion between chemical energy and electrical energy, and can be used to make a battery or a battery pack to supply power to an electrical device.

[0113] The battery cell 10 may be a secondary battery cell. A secondary battery cell refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell 10 is discharged.

[0114] The battery cell 10 can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-hydrogen battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., and the embodiments of the present disclosure are not limited to this.

[0115] Although not shown, the battery cell 10 includes an electrode assembly. The electrode assembly is stacked along a first direction (also referred to as the thickness direction of the battery). The electrode assembly is a component in the battery cell 10 where an electrochemical reaction occurs.

[0116] The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. During the charge and discharge process of the battery cell 10, active ions (such as lithium ions) are inserted and removed between the positive and negative electrode sheets. The separator is placed between the positive and negative electrode sheets to prevent short circuits between the positive and negative electrode sheets while allowing the active ions to pass through.

[0117] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0118] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0119] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0120] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present disclosure is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0121] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, or alloy foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0122] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0123] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, or titanium, etc., may be used. The composite current collector may include a polymer material base layer and a metal layer. The metal foam may be nickel foam, copper foam, aluminum foam, or alloy foam, etc. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0124] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0125] In some embodiments, the separator is a separator. The present disclosure has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0126] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0127] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0128] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0129] In some embodiments, the electrode assembly is a laminate structure.

[0130] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0131] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0132] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0133] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0134] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0135] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0136] In some embodiments, the battery cell 10 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The present disclosure does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0137] In some embodiments, the electrode assembly is provided with tabs 2, which can conduct current from the electrode assembly. The tabs 2 include a positive tab and a negative tab.

[0138] In some embodiments, the battery cell 10 may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0139] As an example, the battery cell 10 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, and a polygonal battery such as a hexagonal battery, etc. There is no special limitation in the present disclosure.

[0140] In the embodiment of the present disclosure, the battery 100 may also be a single physical module including one or more battery cells 10 to provide higher voltage and capacity. When there are multiple battery cells 10, the multiple battery cells 10 may be connected in series, in parallel, or in a hybrid manner.

[0141] The battery 100 of the disclosed embodiment further includes a pressure control unit 20, which is positioned adjacent to at least one battery cell 10 and is configured to apply a force (expansion restraining force) to the battery cell 10 to control the expansion of the battery cell 10, thereby reducing the expansion of the battery cell 10 while maintaining the stress on the surface of the battery cell 10 within an appropriate range. Because a battery cell 10 typically expands most along its thickness direction (a first direction), the pressure control unit 20 is typically positioned adjacent to the surface of the battery cell 10 facing the first direction.

[0142] The unit of stress on a battery cell surface is the ratio of the force applied to the surface of the battery cell to the area, typically measured in Pascals (Pa). The magnitude of the stress depends on the force applied to the surface of the battery cell and the area of ​​the surface.

[0143] The pressure control unit 20 can control the stress on the surface of the battery cell 10 within an appropriate range and control the uniformity of the stress on the surface of the battery cell 10 by applying different forces to the surface of the battery cell 10, thereby reducing the possibility of the battery cell 10 being over-extruded, stress concentration and other adverse conditions, and improving the performance and charge and discharge cycle life of the battery.

[0144] As shown in Figures 6 and 7, the pressure control unit 20 includes a fluid sac 1, which is generally rectangular and flat in shape. Through the flat, rectangular shape of the fluid sac 1, the fluid sac 1 can be in surface contact with the surface of the battery cell 10 facing the first direction, so that the fluid sac 1 can evenly apply force to the battery cell 10, reducing the possibility of stress concentration.

[0145] Illustratively, in the same projection plane perpendicular to the first direction, the projected area of ​​the fluid sac 1 is at least 50% larger than the projected area of ​​the electrode assembly within the battery cell 10, and preferably the same as or larger than the projected area of ​​the electrode assembly within the battery cell 10. In this way, the degree of expansion of the battery cell 10 can be fully and better controlled.

[0146] The elastic effect is achieved by using the compressibility of air and the fluidity of water.

[0147] The fluid sac 1 is an elastic sac with a accommodating cavity 11 formed inside. The accommodating cavity 11 contains a fluid medium such as gas or liquid, and utilizes the compressibility of gas or the fluidity of liquid to achieve elastic effect. That is, the fluid sac 1 can change the amount of fluid medium flowing into the accommodating cavity 11 by controlling the flow of the fluid medium to control the contraction or expansion of the fluid sac 1, thereby applying different forces to the battery cell 10 through different fluid pressures.

[0148] Of course, those skilled in the art will appreciate that in some other embodiments, the fluid bladder 1 may also be in any other suitable shape.

[0149] Specifically, during assembly of the battery 100, the housing assembly 30 may contain only one battery cell 10 or multiple battery cells 10. A pressure control unit 20 may have one or more battery cells 10 on only one side along the first direction, or may have one or more battery cells 10 on both sides. The pressure control unit 20 applies force to the battery cell 10 at least when the battery cell 10 is expanded.

[0150] For example, in the initial state, a fluid medium can be injected into the accommodating cavity 11, and the outer wall of the fluid sac 1 contacts the surface of the battery cell 10 facing the first direction, but no force is applied to the surface. When the battery cell 10 expands, a force is applied to the fluid sac 1, and the fluid sac 1 is elastically deformed after being compressed, thereby applying a reaction force to the battery cell 10, thereby reducing the degree of expansion of the battery cell 10.

[0151] As another example, in the initial state, a fluid medium can be injected into the accommodating cavity 11, and the outer wall of the fluid sac 1 is made to abut the surface of the battery cell 10 facing the first direction, and a certain pre-tightening force is pre-applied to the surface. When the battery cell 10 expands, it needs to overcome the pre-tightening force applied by the fluid sac 1 before expanding, thereby reducing the degree of expansion of the battery cell 10.

[0152] In either case, the fluid bladder 1 can effectively reduce the free expansion of the battery cell 10 , thereby facilitating an increase in the cycle life of the battery 100 .

[0153] In addition, the fluid sac 1 can also adjust the degree of contraction or expansion according to the degree of expansion of the battery cell 10, providing a suitable expansion space for the battery cell 10, so that the expansion force of the battery cell 10 can be released evenly, reducing the possibility of free expansion of the battery cell 10, thereby making the force on the surface of the battery cell 10 facing the stacking direction of the electrode assembly more uniform, reducing the polarization accumulation of the battery cell 10, and helping to improve the performance of the battery 100.

[0154] Moreover, since the fluid sac 1 expands or contracts through the flow of fluid medium, the pressure generated on the sac wall of the fluid sac 1 can be changed by changing the fluid pressure, thereby applying an expansion restraint force to the battery cell 10. Therefore, the expansion degree of the fluid sac 1 can be changed by changing the inflow of fluid medium. Even if it expands or contracts repeatedly, the deformation ability of the fluid sac 1 is not easy to change, thereby providing a reliable and stable force for the battery cell 10.

[0155] Exemplarily, the fluid medium may be a gas, for example, including but not limited to an inert gas.

[0156] As another example, the fluid medium fluid may be a liquid, including but not limited to water, silicone oil, and the like.

[0157] When the fluid medium is liquid, the fluid bladder 1 can not only reduce the expansion of the battery cell 10 , but also play a certain heat exchange role for the battery cell 10 , thereby accelerating the heat dissipation rate of the battery 100 .

[0158] For example, the outer shell of the fluid sac 1 may be provided with a weak portion that ruptures when a preset temperature is reached. In this way, if thermal runaway occurs in the battery cell 10, the weak portion of the fluid sac 1 will dissolve or rupture at high temperatures, allowing the fluid medium within the fluid sac 1 to flow out and rapidly cool the battery cell 10, thereby reducing the severity of thermal runaway.

[0159] In some embodiments, the battery cells 10 include surfaces facing each other along the first direction, and at least when the battery cells 10 are expanded, an average stress in the same surface of the same battery cell 10 is in a range of 0.1 MPa to 2 MPa.

[0160] Therefore, the force (expansion restraining force) applied to the battery cell 10 by the pressure control unit 20 can control the average stress of the surfaces of the battery cell 10 facing each other along the first direction within an appropriate range. In this way, the average stress in the same surface can always be maintained within an appropriate range, which is beneficial to improving the cycle life of the battery cell 10, thereby improving the performance of the battery 100.

[0161] Specifically, the average stress on the surface of the battery cell 10 facing the first direction is M, and the area of ​​contact between the fluid sac 1 and the surface of the battery cell 10 along the first direction is S. Then, in equilibrium, the force F applied by the fluid sac 1 to the surface of the battery cell 10 facing the first direction is F = S * M. Therefore, the calculated F can be used to adjust the amount of fluid medium flowing into the accommodating cavity 11, so that the average stress M on the surface of the battery cell 10 facing the first direction is always maintained within an appropriate range of 0.1 MPa to 2 MPa.

[0162] Exemplarily, the average stress of the surface of the battery cell 10 facing the first direction is 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa or 2 MPa.

[0163] The battery cell 10 can be tested using an in-situ expansion analyzer to find the most suitable average stress on the surface of the battery cell 10 facing the first direction. Then, by adjusting the force applied to the battery cell 10 by the fluid sac 1, the average stress on the surface of the battery cell 10 facing the first direction is always maintained within the optimal range, which is beneficial to improving the cycle life of the battery 100.

[0164] In some embodiments, for the same surface of the same battery cell 10 , at the same time, the value of the minimum stress calculated per unit area divided by the maximum stress calculated per unit area is greater than 50%.

[0165] As a result, the force on the entire surface of the battery cell 10 facing the first direction can be made more uniform, reducing the possibility of stress concentration, so that the battery cell 10 has a good stress environment during the cycle, thereby reducing the possibility of lithium deposition in the battery cell 10, improving the performance of the battery 100, and extending the service life of the battery 100.

[0166] In some embodiments, the maximum pressure that the pressure control unit 20 can apply is in the range of 200N to 4000N.

[0167] Therefore, the pressure control unit 20 can apply a larger expansion restraint force to the battery cell 10, and can control the expansion restraint force within an appropriate range, so as to effectively resist the expansion force of the battery cell 10. Even when the expansion force of the battery cell is large, the average stress of the surface (such as the large surface) of the battery cell can be kept within an appropriate range.

[0168] In addition, since the maximum pressure that the pressure control unit 20 can apply is relatively large, the pressure control unit 20 is less likely to fail to rebound due to elastic failure like a buffer pad, thereby failing to provide a suitable expansion restraining force to the battery cell 10 .

[0169] In some embodiments, as shown in Figures 3 to 7, the fluid sac 1 includes an inlet 3 and an outlet 4, which are in communication with the accommodating chamber 11. The inlet 3 is used to allow the fluid medium to flow into the accommodating chamber 11 from the outside, and the outlet 4 is used to allow the fluid medium to flow out of the accommodating chamber 11. The fluid sac 1 can expand or contract by the inflow or outflow of the fluid medium, respectively.

[0170] The inlet 3 and the outlet 4 are connected to an external fluid medium supply device (not shown in the figure). The fluid medium in the fluid medium supply unit can be injected into the accommodating cavity 11 through the inlet 3, thereby causing the fluid sac 1 to expand, and the fluid medium in the accommodating cavity 11 can also flow out of the accommodating cavity 11 through the outlet 4, thereby causing the fluid sac 1 to contract. Then, the fluid sac 1 can adjust the force applied to the battery cell 10 by changing the pressure according to the expansion degree of the battery cell 10, thereby alleviating the change in internal stress of the battery cell 10 after expansion, thereby limiting the expansion of the battery cell 10 while providing a suitable expansion space for the battery cell 10, reducing the possibility of stress concentration, and maintaining the structural stability of the battery 100.

[0171] For example, valves may be provided at both the inlet 3 and the outlet 4 to control the opening or closing of the inlet 3 and the outlet 4 .

[0172] As another example, flow meters may be provided at the inlet 3 and the outlet 4 so that the fluid pressure can be calculated according to the amount of fluid medium flowing into the accommodating cavity 11, and the magnitude of the force applied by the fluid sac 1 to the surface of the battery cell 10 in the first direction can be obtained.

[0173] In some embodiments, the battery 100 further includes a top cover assembly (not shown), which is located on one side of the housing assembly along the second direction, and the inlet 3 and the outlet 4 are arranged toward the other side of the second direction opposite to the top cover assembly. The second direction is perpendicular to the first direction.

[0174] The top cover assembly refers to a component that covers the opening of the shell assembly to isolate the internal environment of the battery 100 from the external environment. The shape of the top cover assembly can be adapted to the shape of the opening of the shell assembly. Optionally, the top cover assembly can be made of a material with a certain hardness and strength, so that the top cover assembly is not easily deformed when squeezed or collided, so that the battery 100 can have a higher structural strength and improved safety performance. Functional components such as connectors can be provided on the top cover assembly. The connector can be used to electrically connect to the tab 2 of the battery cell 10 for outputting or inputting electrical energy from the battery cell 10.

[0175] Exemplarily, the material of the top cover assembly includes but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0176] The inlet 3 and outlet 4 of the fluid sac 1 need to extend out of the shell assembly to communicate with the external fluid medium supply device, and the top cover assembly usually needs to be sealed and connected to the shell assembly. Therefore, the inlet 3 and outlet 4 are arranged on the other side of the second direction opposite to the top cover assembly, which can facilitate the installation of the top cover assembly. The inlet 3 and outlet 4 will not affect the sealing between the top cover assembly and the shell assembly, nor will they affect the connection between the tab 2 of the battery cell 10 and the connector of the top cover assembly. Moreover, the top cover assembly does not need to reserve additional holes for the inlet 3 and outlet 4 to pass through, thereby reserving sufficient space for arranging the connectors, and can also reduce the assembly difficulty and production cost of the top cover assembly.

[0177] In addition, the shell assembly usually also includes a flame retardant cover, which is provided in the shell assembly and is located on the opposite side of the top cover assembly along the second direction. The flame retardant cover can be broken through when the battery cell 10 inside the battery 100 has a thermal runaway, so that the emissions generated by the thermal runaway can be directionally ejected. Therefore, the structural strength of the flame retardant cover is usually weak, the inlet 3 and the outlet 4 are arranged toward one side of the flame retardant cover, and the flame retardant cover extends out of the shell assembly without excessively affecting the functional effect of the flame retardant cover.

[0178] In some embodiments, as shown in FIG6 , the fluid capsule 1 further includes at least one baffle 5 , which is located in the accommodating cavity 11 and is used to separate the accommodating cavity 11 into at least two spacing areas 111 . The spacing areas 111 are connected to form a curved fluid medium flow channel.

[0179] During the charge and discharge cycle, the battery cell 10 not only expands but also generates heat. If the accumulated heat cannot be effectively dissipated, it will also affect the performance of the battery 100. In severe cases, it may cause the chemical reaction inside the battery cell 10 to get out of control, causing serious consequences such as explosion or fire of the battery 100.

[0180] In the related art, passive heat dissipation of battery cells is usually achieved by setting cooling plates, cooling fins and other heat exchange structures on the bottom surface of the battery cells. However, setting up the heat exchange structure will occupy space in the shell assembly and affect the energy density of the battery. This is especially true for soft-pack battery cells. The thickness of the soft-pack battery cells is relatively thin, and it is difficult to design a heat exchange structure on their bottom surface. Setting up a heat exchange structure between the large surfaces of the soft-pack battery cells will cause a waste of space, which is not conducive to improving space utilization.

[0181] The fluid bladder 1 in the disclosed embodiment can reduce the expansion of the battery cell 10 while also providing good heat dissipation for the battery cell 10. As previously described, the fluid bladder 1 can inject fluid medium into the accommodating cavity 11 or allow the fluid medium to flow out of the accommodating cavity 11 through the inlet 3 and outlet 4, thereby allowing the fluid bladder 1 to contract or expand. However, those skilled in the art should understand that when the battery cell 10 and the pressure control unit 20 are in a state of equilibrium, in addition to closing the inlet 3 and outlet 4 of the fluid bag 1 so that the force applied by the pressure control unit 20 on the battery cell 10 remains unchanged, the inlet 3 and outlet 4 can also be opened at the same time, and the inflow rate and inflow amount of the fluid medium flowing into the accommodating cavity 11 through the inlet 3 are kept consistent with the outflow rate and outflow amount of the fluid medium flowing out of the accommodating cavity 11 through the outlet 4, so that the force applied by the pressure control unit 20 on the battery cell 10 remains unchanged. Moreover, since the fluid medium in the accommodating cavity 11 is circulating, the fluid medium can take away the heat generated by the battery cell 10 while flowing, realizing heat exchange, thereby reducing the expansion of the battery cell 10 while also having a good heat exchange effect on the battery cell 10.

[0182] In order to further improve the heat dissipation of the battery cell 10, the fluid capsule 1 of the embodiment of the present disclosure also includes a baffle 5, which is generally flat. In this way, the fluid medium will be blocked by the baffle 5 when flowing into the accommodating cavity 11, resulting in the fluid medium being unable to flow directly to the outflow port 4. Instead, the fluid medium needs to bypass the baffle 5 and flow through the spacing area 111 defined by the baffle 5 before flowing to the outflow port 4, thus forming a curved fluid medium flow channel. This curved fluid medium flow channel formed by multiple spacing areas 111 can extend the flow distance of the fluid medium and enable the fluid medium to flow through each part of the accommodating cavity 11 as much as possible, thereby increasing the heat exchange area, so that the heat of the battery cell 10 attached to the fluid capsule 1 can be taken away as much as possible.

[0183] The dotted line in FIG6 schematically shows the flow path of the fluid medium in the accommodating chamber 11 provided with the baffle 5 .

[0184] As a result, the fluid bladder 1 allows the fluid medium within the accommodating cavity 11 to flow along the curved fluid medium flow channel, reducing the expansion of the surface of the battery cell 10 facing the first direction while also providing a certain heat exchange effect on this surface, thereby improving the heat dissipation rate of the battery cell 10 and providing favorable temperature conditions for the battery 100, thereby ensuring the stability of the battery 100's performance and reducing the risk of thermal runaway. Furthermore, the battery 100 housing assembly eliminates the need for separate heat exchange structures such as cooling plates, which helps reduce the number of components, lowers production costs, and improves space utilization within the battery 100.

[0185] For example, the baffle 5 and the fluid bladder 1 may be formed as an integral structure.

[0186] As another example, the baffle 5 can be fixedly connected to the inner wall of the accommodating cavity 11 of the fluid bladder 1 by any suitable fixing means such as bonding.

[0187] In some embodiments, there are multiple baffles 5 , which extend along the second direction and are spaced apart and arranged in parallel along the third direction, wherein the first direction, the second direction, and the third direction are perpendicular to each other.

[0188] As shown in Figures 6 and 7 , in the embodiment of the present disclosure, there are three baffles 5. In some other embodiments, the number of baffles 5 may be one, two, or more (more than three). The embodiment of the present disclosure does not impose a specific limit on the number of baffles 5 and may be set according to the actual size of the fluid bladder 1.

[0189] Therefore, by providing the baffle 5 in the accommodating cavity 11 , the flow path of the fluid medium can be made longer, so that the fluid medium can flow through as much of the surface of the battery cell 10 along the first direction as possible in the accommodating cavity 11 , thereby achieving better heat dissipation effect.

[0190] Furthermore, the parallel arrangement of the multiple baffles 5 allows for more uniform sizes of the spaced regions 111 defined by the baffles 5, allowing the fluid medium to flow through these uniformly spaced regions and dissipate heat evenly from the battery cells. Furthermore, the parallel arrangement of the baffles 5 makes the structure easier to manufacture and process, thereby reducing production costs.

[0191] The embodiment of the present disclosure does not impose a specific limit on the extension length of the baffle 5 , as long as the fluid medium can flow through as many parts of the accommodating cavity 11 as possible without affecting the flow of the fluid medium.

[0192] In the embodiment of the present disclosure, the extension length of each baffle 5 is the same, and the spacing distance between two adjacent baffles 5 along the third direction is the same. In some other embodiments, the extension length of each baffle 5 may also be different, and the spacing distance between two adjacent baffles 5 along the third direction may also be different.

[0193] In some embodiments, as shown in Figures 5 and 6 , the pressure fluid bladder 1 includes a top wall 12, a bottom wall 13, and a plurality of side walls 14 connecting the top wall 12 and the bottom wall 13. The top wall 12, the bottom wall 13, and the plurality of side walls 14 define a receiving chamber 11. The inlet 3 and the outlet 4 are provided on the bottom wall 13. One end of each baffle 5 is connected to the inner wall surface of the top wall 12 or the bottom wall 13, and the other end is suspended in the air.

[0194] As a result, a certain gap is formed between the suspended end of the baffle 5 and the interior of the top wall 12 or the bottom wall 13, so that the multiple spacing areas 111 separated by the baffle 5 can be connected, and the flow path of the fluid medium can be made longer without affecting the flow of the fluid medium, thereby better dissipating heat for the battery cell 10.

[0195] Of course, those skilled in the art will appreciate that the baffle 5 is not limited to the above arrangement. In other embodiments, the baffle 5 may be connected at both ends to the inner surfaces of the top wall 12 and the bottom wall 13, respectively, and disconnected in the middle of the baffle 5 to connect the various compartments 111.

[0196] In some embodiments, along the third direction, the extension directions of adjacent baffles 5 along the first direction are opposite.

[0197] Specifically, the extension directions of adjacent baffles 5 along the first direction are opposite, and along the extension direction of the baffle 5, two adjacent baffles 5 partially overlap, thereby forming a curved fluid medium flow channel with a simple structure, so that the fluid medium can dissipate heat to the battery cell 10 more fully and evenly.

[0198] The embodiment of the present disclosure does not specifically limit the size of the overlapping area of ​​the baffle 5, as long as it can extend the flow path and does not affect the flow of the fluid medium.

[0199] In some embodiments, as shown in Figure 6, along the third direction, the baffle 5 closest to the inlet 3 extends from the inner wall surface of the bottom wall 13 toward the inner wall surface of the top wall 12 along the second direction; and / or along the third direction, the baffle 5 closest to the outflow port 4 extends from the inner wall surface of the bottom wall 13 toward the inner wall surface of the top wall 12 along the second direction.

[0200] Since the inlet 3 and the outlet 4 are arranged on the bottom wall 13 of the fluid sac 1, the baffle 5 closest to the inlet 3 and the outlet 4 extends from the inner wall surface of the bottom wall 13. When the fluid medium flows into the accommodating cavity 11 of the fluid sac 1 through the inlet 3, it cannot flow directly to the outlet 4 along the bottom wall 13 of the fluid sac 1 along the third direction, but needs to bypass the baffle 5 and flow through the spacing area 111 defined by the baffle 5 before flowing to the outlet 4, thereby extending the flow path of the fluid medium, so that the fluid medium can fully and evenly dissipate heat to the battery cell 10, and increase the heat dissipation area and heat dissipation efficiency.

[0201] In some embodiments, as shown in FIG. 7 , the baffle 5 is in sealing contact with the inner wall surfaces of two side walls 14 that are arranged opposite to each other along the third direction.

[0202] As a result, the fluid medium cannot penetrate the baffle 5 when flowing, and can only flow along the prescribed curved fluid medium flow channel, thereby better dissipating heat from the battery cell 10 .

[0203] Of course, those skilled in the art should understand that in some other embodiments, the baffle 5 may not be completely in close contact with the inner wall surface of the side wall 14, as long as the fluid medium can flow along the curved fluid medium flow channel to perform heat exchange.

[0204] In some embodiments, the fluid bladder 1 is made of elastic material.

[0205] The elastic material has good elasticity, so it can expand or contract well through the flow of the fluid medium, so that the fluid sac 1 can be compressed and produce elastic deformation along the direction of the expansion force of the battery cell 10 after being subjected to the expansion force released by the battery cell 10, and can rebound after the expansion force of the battery cell 10 is reduced, so as to adapt to the different expansion forms of the battery cell 10, so that the fluid sac 1 can always apply appropriate force to the surface of the battery cell 10 along the first direction, while reducing the expansion of the battery cell 10, providing the battery cell 10 with appropriate expansion space, so that the stress on the surface of the battery cell 10 along the first direction is more uniform, reducing the possibility of stress concentration in the battery cell 10, and effectively improving the performance of the battery 100.

[0206] The baffle 5 provided in the fluid sac 1 can also be made of elastic material. In this way, the baffle 5 can deform along with the expansion or contraction of the fluid sac 1, thereby better blocking the fluid medium in the accommodating cavity 11, so that the fluid medium can always flow according to the prescribed flow path.

[0207] In some embodiments, the elastic material comprises elastic rubber.

[0208] The elastic rubber has good elasticity and is simple to shape, which can effectively reduce processing costs. In addition, the elastic rubber has good wear resistance and aging resistance, which can improve the performance of the fluid bladder 1.

[0209] Of course, those skilled in the art should understand that the elastic material does not only include rubber, and the fluid bladder 1 can also be made of any other suitable elastic material.

[0210] In some embodiments, in each pressure control unit 20 , within the same projection area perpendicular to the first direction, the projection area of ​​the fluid bladder 1 is larger than the projection area of ​​the electrode assembly in the battery cell 10 .

[0211] Therefore, the fluid sac 1 can more effectively restrain the expansion of the battery cell 10, reducing the possibility of adverse conditions such as wrinkling of the electrode assembly's pole piece due to the free expansion of the battery cell 10, thereby maintaining the cycle life of the battery 100 and the good performance of the battery 100.

[0212] In some embodiments, along the first direction, the pressure control unit 20 is disposed adjacent to at least one of the surfaces of the battery cell 10 facing the first direction.

[0213] In the initial state, that is, when the battery cell 10 has not yet expanded, the adjacent setting may mean that the pressure control unit 20 can be set in contact with the battery cell 10, or it may mean that the pressure control unit 20 is set close to but not in contact with the battery cell 10. The embodiments of the present disclosure do not specifically limit this, as long as the pressure control unit 20 can apply force to the battery cell 10 at least when the battery cell 10 expands, so as to control the degree of expansion of the battery cell 10.

[0214] Since the battery cell 10 usually expands along the stacking direction (first direction) of the electrode assembly, the pressure control unit 20 is arranged adjacent to at least one of the surfaces of the battery cell 10 facing the first direction, and can apply an expansion restraining force to the surface of the battery cell 10 facing the first direction at least when the battery cell 10 is expanded, thereby controlling the degree of expansion of the battery cell 10.

[0215] In some embodiments, there are multiple battery cells 10 arranged along the first direction. The pressure control unit 20 is disposed between adjacent battery cells 10 and / or between the battery cells 10 and the inner wall of the housing assembly 30 adjacent to the battery cells 10 .

[0216] Thus, a pressure control unit 20 can simultaneously apply force to adjacent battery cells 10, and can also apply appropriate force to the surface of the battery cell 10 adjacent to the shell assembly facing the first direction, thereby helping to provide appropriate expansion force for the battery cell and improving battery performance.

[0217] Furthermore, sharing the pressure control unit 20 between adjacent battery cells 10 helps reduce the number of parts. Because the pressure control unit 20 can be positioned between the inner wall of the housing assembly 30 and the battery cells 10 adjacent to that inner wall, expansion can be restrained even on the surface of the battery cells 10 adjacent to the inner wall. This allows expansion restraint and pressure control to be applied to the large surface of each battery cell 10 housed in the housing assembly 30.

[0218] In some embodiments, as shown in Figures 3 and 4, the pressure control unit 20 can also be arranged between every two adjacent battery cells 10, and / or at least two battery cells 10 form a battery cell group, and the pressure control unit 20 is arranged between the two battery cell groups, and / or the pressure control unit 20 is arranged between the battery cell group and the battery cell 10 adjacent to the battery cell group.

[0219] Therefore, the pressure control unit 20 can be arranged at different positions in the shell assembly 30 according to different conditions of the battery cell 10. For example, when the thickness of a single battery cell 10 is large, in order to ensure the average stress on the surface of the battery cell 10 facing the first direction, the side of the pressure control unit 20 facing the first direction can only apply force to one battery cell 10. When the thickness of a single battery cell 10 is small, the side of the pressure control unit 20 facing the first direction can also apply force to multiple battery cells 10 at the same time, thereby effectively reducing the expansion of the battery cell 10.

[0220] The number of battery cells 10 on both sides of the pressure control unit 20 facing the first direction can be the same or different. The disclosed embodiment does not impose a specific limit on the number of battery cells 10 on both sides of the pressure control unit 20 facing the first direction, as long as the average stress on the surfaces of these battery cells 10 facing the first direction is within a preset range.

[0221] In some embodiments, the battery cell 10 includes a soft-pack battery cell or a square-shell battery cell.

[0222] Soft-pack battery cells are typically encapsulated in soft aluminum-plastic packaging film, which has poor resistance to deformation and is therefore more susceptible to expansion during the charge and discharge process. However, the disclosed embodiment, by providing a pressure control unit 20, can effectively reduce the expansion of soft-pack battery cells, thereby reducing the occurrence of adverse phenomena such as lithium deposition caused by excessive expansion of soft-pack battery cells, thereby improving the charge and discharge cycle life and performance of battery 100.

[0223] The square-shell battery cells will also expand during the charge and discharge process. The pressure control unit 20 can also apply force to the square-shell battery cells, thereby controlling the expansion degree of the square-shell battery cells.

[0224] However, those skilled in the art should understand that the battery cells 10 are not limited to soft-pack battery cells and square-shell battery cells. The pressure control unit 20 of the embodiment of the present disclosure can also be used to control the expansion degree of other battery cells.

[0225] As shown in FIG5 , the second aspect of the present disclosure provides a pressure control unit 20. The pressure control unit 20 is used for a battery 100. The battery 100 includes at least one battery cell 10. The battery cell 10 includes an electrode assembly stacked along a first direction. The battery cell 10 includes surfaces facing each other along the first direction. The pressure control unit 20 includes a fluid sac 1. The fluid sac 1 has a receiving cavity 11 formed therein. The receiving cavity 11 contains a fluid medium. The fluid sac 1 can contract or expand due to the flow of the fluid medium, thereby applying the force to the battery cell 10 through the fluid pressure generated by the fluid medium. The pressure control unit 20 is configured to apply a force to the battery cell 10 to control the stress on the surface of the expanded battery cell 10, at least when the battery cell 10 is expanded.

[0226] The pressure control unit 20 is at least able to apply force to the battery cell 10 when the battery cell 10 is in an expanded state, thereby reducing the expansion of the battery cell 10, and the pressure control unit 20 configured as a fluid sac 1 can also adjust the degree of contraction or expansion by changing the flow of the fluid medium according to the expansion degree of the battery cell 10, providing a suitable expansion space for the battery cell 10, so that the expansion force of the battery cell 10 can be released evenly, reducing the polarization accumulation of the battery cell 10, which is beneficial to improving the performance and charge and discharge cycle life of the battery 100.

[0227] In some embodiments, the maximum pressure that the pressure control unit 20 can apply is in the range of 200N to 4000N.

[0228] As a result, the pressure control unit 20 can exert a significant expansion-restraining force on the battery cell 10 and control this force within an appropriate range, effectively counteracting the expansion force of the battery cell 10. Even in the presence of significant expansion force, the average stress on the surface (e.g., the large surface) of the battery cell 10 can be maintained within an appropriate range. Furthermore, the maximum pressure that the pressure control unit 20 can exert is relatively high, making it less likely that the battery cell 10 will be unable to rebound due to elastic failure, thereby preventing the battery cell 10 from being unable to provide the appropriate expansion-restraining force.

[0229] In some embodiments, the fluid sac 1 includes an inlet 3 and an outlet 4, each of which is in communication with the accommodating chamber 11. The inlet 3 is used to allow a fluid medium to flow into the accommodating chamber 11 from the outside, and the outlet 4 is used to allow the fluid medium to flow out of the accommodating chamber 11. The fluid sac 1 can expand or contract by the inflow or outflow of the fluid medium.

[0230] In this way, the fluid medium can flow into or out of the accommodating cavity 11 according to the expansion degree of the battery cell 10, and the different pressures generated by different amounts of fluid medium can be used to adjust the force applied to the surface of the battery cell 10. This not only limits the expansion of the battery cell 10, but also reserves a suitable expansion space for the battery cell 10, so that the stress on the surface of the battery cell is uniform.

[0231] In addition, the flow circulation of the fluid medium inside the accommodating chamber 11 can be achieved through the inlet 3 and the outlet 4, thereby reducing the expansion of the battery cell 10 while taking away the heat of the battery cell 10 to achieve heat exchange. In this way, pressure management and temperature management are combined into one, and there is no need to set up an additional heat exchange structure, which effectively saves space and reduces weight.

[0232] In some embodiments, as shown in FIG6 , the fluid capsule 1 further includes at least one baffle 5 , which is located in the accommodating cavity 11 and is used to separate the accommodating cavity 11 into at least two spacing areas 111 . The spacing areas 111 are connected to form a curved fluid medium flow channel.

[0233] In this way, the flow path of the fluid medium in the accommodating cavity 11 can be extended, so that the fluid medium can flow through more parts of the accommodating cavity 11 via the bent fluid medium flow channel, thereby increasing the heat dissipation area of ​​the surface of the battery cell 10 and further improving the heat dissipation efficiency.

[0234] As shown in FIG2 , the third aspect of the present disclosure provides a battery pack 400 , which includes a box body 401 and at least one battery 100 according to the first aspect of the present disclosure, wherein the battery 100 is accommodated in the box body 401 .

[0235] Since the batteries 100 according to the first aspect of the present disclosure can be used in groups, higher total energy can be provided.

[0236] In addition, since the battery pack 400 provided in the embodiment of the present disclosure adopts a battery cell 10 equipped with a pressure control unit 20, the average stress of the large surface of the battery cell 10 is within an appropriate range and has good uniformity, and the risk of stress concentration is reduced. Therefore, the risk of the battery pack 400 having a reduced charge and discharge cycle life due to the expansion of the battery cell 10 is reduced.

[0237] A fourth aspect of the present disclosure provides an electrical device, which includes the battery 100 described in the first aspect of the present disclosure or the battery pack 400 described in the third aspect of the present disclosure for providing electrical energy.

[0238] Since the electric device of the embodiment of the present disclosure adopts the battery pack 400 with good performance as described above, the time spent on maintenance is reduced, and the risk of failure of the electric device due to failure of the battery pack 400 is reduced.

[0239] A fifth aspect of the present disclosure provides an energy storage device, which includes the battery 100 described in the first aspect of the present disclosure or the battery pack 400 described in the third aspect of the present disclosure for storing or providing electrical energy.

[0240] Since the energy storage device of the embodiment of the present disclosure adopts the battery pack 400 with good performance as described above, the time spent on maintenance is reduced, and the risk of failure of the electrical device due to failure of the battery pack 400 is reduced.

[0241] Specific examples of some embodiments of the present disclosure are described below with reference to the accompanying drawings.

[0242] As a specific example, the battery 100 includes a battery cell (battery cell 10) and a pressure control structure (pressure control unit 20). The pressure control structure is an air bag, the battery cell is a soft-pack battery cell, and the pressure control structure can be placed between two battery cells. The pressure control structure covers the large surface (the surface facing the first direction) of the internal winding / laminated layer (electrode assembly) of the battery cell, and at least needs to cover more than 50% of the area of ​​the large surface of the internal winding / laminated layer of the battery cell. One or more battery cells are placed on both sides of the pressure control structure facing the first direction. The pressure control structure can simultaneously control the expansion degree of the batteries on both sides. The best placement method is to place two battery cells on a single side of the pressure control structure.

[0243] The pressure control structure of the airbag structure includes an air inlet (inlet 3) and an air outlet (outlet 4) that interact with the outside world. The air inlet is used to inject gas or liquid (fluid medium) into the airbag, thereby controlling the thickness of the airbag and the pressure applied to the battery cell by regulating the gas pressure or liquid pressure, so that the average stress of the large surface of the battery cell is maintained in the range of 0.1MPa to 2MPa, and the value of the minimum stress calculated per unit area divided by the maximum stress calculated per unit area on the same surface of a single battery cell at the same time is greater than 50%, thereby ensuring the uniformity of the stress on the large surface of the battery cell.

[0244] The airbag is designed with an isolation fence (baffle 5). The isolation fence, with its various notches, allows the gas or liquid entering the airbag to flow along a curved flow path (the flow path of the fluid medium) within the airbag, ensuring uniform cooling and heat dissipation over the large surface of the battery cell. The airbag should contain at least one isolation fence, with an upper limit determined based on actual dimensions and requirements. The isolation fence is securely attached to the inner wall of the airbag, at least tightly sealed against the large inner wall, ensuring that the gas or liquid flows and cools along the flow path.

[0245] The above embodiments are intended only to illustrate the technical solutions of the present disclosure, and are not intended to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. Such modifications or replacements do not deviate from the essence of the corresponding technical solutions and are intended to be included within the scope of the present disclosure. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts.

Claims

1. A battery, comprising: housing assembly; at least one battery cell housed in the housing assembly, wherein the battery cell includes an electrode assembly stacked along a first direction; and at least one pressure control unit, the pressure control unit comprising a fluid bladder having an accommodation cavity formed therein, the accommodation cavity accommodating a fluid medium, the fluid bladder being capable of contracting or expanding due to the flow of the fluid medium, thereby exerting a force on the battery cell through fluid pressure generated by the fluid medium; The pressure control unit applies the force to the battery cell at least when the battery cell is expanded, so as to control the stress on the surface of the expanded battery cell.

2. The battery according to claim 1, wherein The battery cells include surfaces facing each other along the first direction, At least in a state where the battery cell is expanded, an average stress in the same surface of the same battery cell is in a range of 0.1 MPa to 2 MPa.

3. The battery according to claim 1 or 2, wherein: For the same surface of the same battery cell, at the same time, a value of the minimum stress calculated per unit area divided by the maximum stress calculated per unit area is greater than 50%.

4. The battery according to any one of claims 1 to 3, wherein The maximum pressure that can be applied by the pressure control unit is in the range of 200N to 4000N.

5. The battery according to any one of claims 1 to 4, wherein The fluid bag includes an inlet and an outlet, the inlet and the outlet are respectively connected to the accommodating cavity, the inlet is used for allowing the fluid medium to flow into the accommodating cavity from the outside, and the outlet is used for allowing the fluid medium to flow out of the accommodating cavity; The fluid bladder can be expanded or deflated by the inflow or outflow of the fluid medium.

6. The battery according to claim 5, wherein The battery further includes a top cover assembly, the top cover assembly being located on one side of the housing assembly along the second direction, the inlet and the outlet being arranged toward the other side of the second direction opposite to the top cover assembly; The second direction is perpendicular to the first direction.

7. The battery according to any one of claims 1 to 6, wherein The fluid bladder further comprises at least one baffle, which is located in the accommodating cavity and is used to separate the accommodating cavity into at least two spaced areas, wherein the spaced areas are connected to form a tortuous fluid medium flow channel.

8. The battery according to claim 7, wherein There are multiple baffles, and the multiple baffles extend along the second direction and are spaced apart and arranged in parallel along the third direction; The first direction, the second direction and the third direction are perpendicular to each other.

9. The battery according to claim 8, wherein The fluid bag includes a top wall, a bottom wall, and a plurality of side walls connecting the top wall and the bottom wall, wherein the top wall, the bottom wall, and the plurality of side walls define the accommodating cavity; The inlet and the outlet are provided on the bottom wall; One end of each baffle is connected to the inner wall surface of the top wall or the bottom wall, and the other end is suspended.

10. The battery according to claim 9, wherein Along the third direction, the adjacent baffles extend in opposite directions along the first direction.

11. The battery according to claim 10, wherein Along the third direction, the baffle closest to the inlet extends along the second direction from the inner wall surface of the bottom wall toward the inner wall surface of the top wall; and / or Along the third direction, the baffle closest to the outflow port extends along the second direction from the inner wall surface of the bottom wall toward the inner wall surface of the top wall.

12. The battery according to any one of claims 9 to 11, wherein The baffle is sealed against inner wall surfaces of the two side walls that are arranged opposite to each other along the third direction.

13. The battery according to any one of claims 1 to 12, wherein The fluid bladder is made of elastic material.

14. The battery according to claim 13, wherein The elastic material includes elastic rubber.

15. The battery according to any one of claims 1 to 14, wherein In each of the pressure control units, within the same projection area perpendicular to the first direction, a projection area of ​​the fluid sac is larger than a projection area of ​​the electrode assembly within the battery cell.

16. The battery according to any one of claims 1 to 15, wherein Along the first direction, the pressure control unit is disposed adjacent to at least one of the surfaces of the battery cells facing the first direction.

17. The battery according to claim 16, wherein There are multiple battery cells, and the multiple battery cells are arranged along the first direction; The pressure control unit is disposed between adjacent battery cells and / or between the battery cells and an inner wall of the housing assembly adjacent to the battery cells.

18. The battery according to claim 17, wherein The pressure control unit is provided between every two adjacent battery cells; and / or At least two of the battery cells form a battery cell group, and the pressure control unit is provided between the two battery cell groups; and / or The pressure control unit is provided between the battery cell group and the battery cells adjacent to the battery cell group.

19. The battery according to any one of claims 1 to 18, wherein The battery cells include soft-pack battery cells or square-shell battery cells.

20. A pressure control unit for a battery, The battery includes at least one battery cell, the battery cell includes electrode assemblies stacked along a first direction, and the battery cells include surfaces facing each other along the first direction; The pressure control unit includes a fluid bladder having an accommodation cavity formed therein. The accommodation cavity accommodates a fluid medium. The fluid bladder can contract or expand due to the flow of the fluid medium, thereby exerting a force on the battery cell through the fluid pressure generated by the fluid medium. in, The pressure control unit is configured to apply a force to the battery cell to control stress on a surface of the swollen battery cell at least when the battery cell is swollen.

21. The pressure control unit according to claim 20, wherein: The maximum pressure that can be applied by the pressure control unit is in the range of 200N to 4000N.

22. The pressure control unit according to claim 20 or 21, wherein: The fluid bag includes an inlet and an outlet, the inlet and the outlet are respectively connected to the accommodating cavity, the inlet is used for allowing the fluid medium to flow into the accommodating cavity from the outside, and the outlet is used for allowing the fluid medium to flow out of the accommodating cavity; The fluid bladder can be expanded or deflated by the inflow or outflow of the fluid medium.

23. The pressure control unit according to any one of claims 20 to 22, wherein: The fluid bladder further comprises at least one baffle, which is located in the accommodating cavity and is used to separate the accommodating cavity into at least two spaced areas, wherein the spaced areas are connected to form a tortuous fluid medium flow channel.

24. A battery pack, comprising: Box; and At least one battery according to any one of claims 1 to 19, the battery being housed in the casing. 25 . An electrical device comprising the battery according to claim 1 or the battery pack according to claim 24 for providing electrical energy. 26 . An energy storage device comprising the battery according to claim 1 or the battery pack according to claim 24 for storing or providing electrical energy.

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