Battery cell, battery pack, energy storage system and power utilization device

Abstract

The utility model discloses a battery monomer, battery pack, energy storage system and power utilization device, said battery monomer includes: shell and roll core, shell has the accommodation cavity, roll core is provided in the accommodation cavity, roll core includes: core body and cushion pad, core body winds around the winding center, and the winding center has the center hole, the cushion pad is provided with the cushion pad. The core body is provided with a thinned area and a middle area which are sequentially arranged in the winding axial direction, the buffering cushion is arranged in the center hole and comprises a middle part and a supporting part which are sequentially arranged in the winding axial direction, and the thickness of the supporting part in the winding radial direction is larger than that of the middle part in the winding radial direction. Therefore, stress can be balanced, edge lithium precipitation can be prevented, the inner ring pole piece can be supported, inner ring corner gaps can be reduced, inner ring lithium precipitation can be improved, the lithium precipitation probability of the roll core can be reduced, the cycle life of the roll core can be prolonged, the reliability of the roll core can be improved, the brittle failure probability of the inner ring pole piece can be reduced, the inner short probability can be reduced, and potential safety hazards can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery cell, a battery pack, an energy storage system and an electrical device. Background Art

[0002] In the related art, the diaphragm and the anode and cathode plates on both sides of the diaphragm form a winding body (core body), and the winding body is wound around a winding center to form a winding core. The edge area of ​​the diaphragm needs to be formed into a thinning area to improve the shrinkage and expansion of the winding core during charging and discharging.

[0003] However, the setting of the thinning zone will cause the force on the edge of the core to be less than that in the middle, resulting in lithium deposition. The corner gap of the bent part of the core is too large, which is also prone to lithium deposition, reducing the cycle life of the core. The inner ring of the core is prone to brittle fracture, posing a risk of internal short circuit and a safety hazard. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a battery cell with higher working reliability, lower safety risks and longer cycle life.

[0005] The utility model also provides a battery pack using the battery monomer.

[0006] The utility model further proposes an energy storage system having the above battery pack.

[0007] The utility model also provides an electric device adopting the energy storage system.

[0008] In the first aspect, an embodiment of the present application provides a battery cell, comprising: a shell and a winding core, the shell having a accommodating cavity, the winding core being arranged in the accommodating cavity, the winding core comprising: a core body and a buffer pad, the core body being wound around a winding center, and the winding center having a center hole, the core body having a thinning zone and a middle zone arranged in sequence along the winding axis, the pole piece thickness of the thinning zone being smaller than the pole piece thickness of the middle zone, the buffer pad being arranged in the center hole, the buffer pad comprising a middle portion and a supporting portion arranged in sequence along the winding axis, the supporting portion being arranged corresponding to the thinning zone, the middle portion being arranged corresponding to the middle zone, and the thickness of the supporting portion in the winding radial direction is greater than the thickness of the middle portion in the winding radial direction.

[0009] According to the battery cell of the embodiment of the utility model, a buffer pad is provided, and the supporting part of the buffer pad corresponds to the thinned area, and the middle part corresponds to the middle area, so that the force can be balanced to prevent lithium deposition at the edge, and at the same time, the inner circle pole piece is supported, the inner circle corner gap is reduced, and the inner circle lithium deposition is improved, so as to reduce the probability of lithium deposition in the winding core, improve the cycle life and reliability of the winding core, and at the same time, the probability of brittle fracture of the inner circle pole piece can be reduced to reduce the probability of internal short and reduce safety hazards.

[0010] According to some embodiments of the present invention, in a direction toward the middle portion, a size of the support portion in the winding radial direction gradually decreases.

[0011] In the above technical solution, on the one hand, the support portion with gradually decreasing size in the winding radial direction can match the thinning area setting to improve the supporting effect on the thinning area. On the other hand, the smoothly transitioning length edge can prevent scratches on the pole piece or diaphragm, thereby improving the stability and reliability of the winding core.

[0012] In some embodiments, an angle formed between the length edge of the support portion and the winding axis is 0° to 60°.

[0013] In the above technical solution, the thickness of the support part can be made more reasonable to prevent the edge area of ​​the support part from being too thick, resulting in the force on the edge being greater than the force in the middle area, thereby improving the mechanical balance effect, effectively improving edge lithium deposition, and extending the cycle life and working stability.

[0014] In some embodiments, an angle formed between the length edge of the support portion and the winding axis is 0° to 45°.

[0015] In the above technical solution, the thickness of the end of the support part away from the middle part is more reasonable, the improvement effect of edge lithium deposition is better, the overall space occupied by the buffer pad is smaller, and the arrangement of the winding core can be more compact.

[0016] In some embodiments, a dimension of the middle portion in the winding radial direction is 0.5 mm to 3 mm.

[0017] In the above technical solution, on the one hand, the width of the middle part can be prevented from being too small to maintain the elastic support and cushioning effect of the middle part. On the other hand, the width of the middle part can be prevented from being too large, which can reduce material costs while taking into account the space occupied by the cushion.

[0018] In some embodiments, the maximum dimension of the support portion in the winding radial direction is W1, the dimension of the middle portion in the winding radial direction is W2, and 1<W1 / W2≤2 is satisfied.

[0019] In the above technical solution, while making the support part and the thinning area fit more closely to improve the support and buffering effects, the size of the support part can also be taken into account to prevent the support part from being too large, thereby reducing material costs and taking into account the space occupied by the winding core to reduce the difficulty of layout.

[0020] According to some embodiments of the present invention, the dimension of the support portion in the winding axial direction is greater than or equal to the dimension of the thinning zone in the winding axial direction.

[0021] In the above technical solution, the length of the support portion is made greater than or equal to the length of the thinning zone, so that the thinning zone can be located in the area where the support portion is located, so that the difference between the width dimension of the thinning zone and the width dimension of the middle zone is smaller, the flatness is higher, the force distribution is more uniform, the edge lithium plating inhibition effect is better, and the expansion force balance effect is better.

[0022] In some embodiments, the buffer pad further includes: an extension portion, wherein the extension portion is located at an end of the support portion away from the middle portion.

[0023] In the above technical solution, a certain assembly margin can be reserved through the extension part to reduce the assembly accuracy requirement of the core. Even if the thickest position of the support part is not aligned with the thinning area, the support buffer effect of the support part can be maintained to improve the assembly efficiency.

[0024] In some embodiments, the number of the support portions is consistent with the number of the thinned areas, and the support portion is formed at at least one end of the middle portion.

[0025] In a second aspect, an embodiment of the present application provides a battery pack, including: the battery cell described in the above embodiment.

[0026] In a third aspect, an embodiment of the present application provides an energy storage system, including: the battery pack described in the above embodiment.

[0027] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising: the battery pack described in the above embodiment.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0030] Figure 1 is a schematic diagram of an electrical device according to an embodiment of the utility model;

[0031] Figure 2 is a schematic diagram of a battery pack according to an embodiment of the utility model;

[0032] Figure 3 is a schematic diagram of a winding core according to an embodiment of the utility model;

[0033] Figure 4 is a schematic diagram of a cushion according to an embodiment of the utility model;

[0034] Figure 5 is a schematic diagram of another buffer pad according to an embodiment of the utility model;

[0035] Figure 6 is a schematic diagram of another buffer pad according to an embodiment of the utility model;

[0036] Figure 7 is a schematic diagram of a battery cell according to an embodiment of the utility model;

[0037] Figure 8 It is a schematic diagram of another battery cell according to an embodiment of the utility model.

[0038] Reference numerals:

[0039] Core 100,

[0040] Core 10, anode pole piece 11, cathode pole piece 12, diaphragm 13,

[0041] The core inner ring 101, the core outer ring 102, the core middle ring 103,

[0042] Cushion pad 20, middle portion 21, support portion 22, extension portion 23,

[0043] Battery cell 200, housing 210,

[0044] Battery pack 300, power device 400, controller 500, motor 600, box 700,

[0045] Winding center a, thinning area b, middle area c. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0047] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those generally understood by technicians in the technical field of the present invention; the terms used in the present invention and in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0048] The reference to "embodiment" in the present invention means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection", and "attachment" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] The term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0051] In the embodiments of the present invention, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present invention shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present invention.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] In the description of the present invention, a first feature being “above” or “below” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact but are in contact with each other via another feature therebetween.

[0054] In the description of the present invention, a first feature “above”, “over” and “above” a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0055] The term "plurality" used in the present invention refers to more than two (including two).

[0056] In the embodiment of the utility model, the winding core 100 is anode electrode sheet 11, cathode electrode sheet 12 and diaphragm 13 rolled together by the winding needle mechanism of the winding machine. Adjacent cathode electrode sheets 12 and anode electrode sheets 11 are separated by diaphragm 13 to prevent short circuit. The winding needle mechanism defines a winding center a. The winding needle can be needle-shaped, so that the core body 10 can be wound around an axis defined by the needle-shaped winding needle as the winding center a to form a cylindrical winding core, which can be processed into a cylindrical battery cell. The winding needle can also be plate-shaped, and the core body 10 can also be wound around a plane defined by the plate-shaped winding needle to form a square winding core, which can be processed into a square battery cell.

[0057] In the embodiment of the present invention, the battery cell 200 may be a secondary battery. A secondary battery refers to a battery cell 200 that can be continuously used by activating active materials by charging after the battery cell 200 is discharged.

[0058] The battery cell 200 can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present invention.

[0059] The battery pack 300 mentioned in the embodiment of the present invention refers to a single physical module including one or more battery cells 200 to provide higher voltage and capacity. When there are multiple battery cells 200, the multiple battery cells 200 are connected in series, in parallel or in mixed connection through a busbar.

[0060] In some embodiments, a plurality of battery cells 200 may be combined into a battery module, that is, when there are a plurality of battery cells 200 , the plurality of battery cells 200 are arranged and fixed to form a battery module.

[0061] In some embodiments, the battery pack 300 includes a case 700 and battery cells 200, at least one battery cell 200 or at least one battery module is accommodated in the case 700, and the case 700 has an accommodating space, and at least one battery cell 200 or at least one battery module is accommodated in the accommodating space.

[0062] In some embodiments, the box 700 can be used as a part of the chassis structure of the vehicle. For example, part of the box 700 can become at least a part of the floor of the vehicle, or part of the box 700 can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0063] In some embodiments, the battery pack 300 or the battery module may be part of an energy storage system, which may be an energy storage container, an energy storage cabinet, etc., in which batteries and energy shut-off modules are integrated.

[0064] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety performance of the battery must also be considered.

[0065] It is understandable that since the energy people need is highly temporal and spatial, in order to rationally use energy and improve energy utilization, it is necessary to use a medium or device to store one form of energy in the same form or convert it into another form of energy, and then release it in a specific form of energy based on future application needs. As we all know, to achieve the goal of carbon neutrality, green energy is currently mainly used to replace fossil energy to achieve the purpose of generating green electricity.

[0066] The current green energy mainly includes solar energy, wind energy, hydropower, etc. However, solar energy and wind energy generally have problems of strong intermittency and large volatility, which will cause unstable voltage of the green power grid (not enough electricity during peak hours and too much electricity during low hours). Unstable voltage will cause damage to electricity. Therefore, it may cause the problem of "wind and solar power abandonment" due to insufficient electricity demand or insufficient grid acceptance capacity.

[0067] To solve the problem of insufficient electricity demand or insufficient grid acceptance capacity, we must rely on energy storage systems, etc. That is, the energy storage system converts electrical energy into other forms of energy through physical or chemical means and stores it, and then converts the energy stored in the energy storage system into electrical energy when needed. In simple terms, the energy storage system is similar to a large "power bank", which stores electrical energy when there is sufficient light energy and wind energy, and releases the stored electrical energy when needed.

[0068] At present, energy storage (i.e. energy storage) has a wide range of application scenarios, including power generation side energy storage, grid side energy storage, renewable energy grid-connected energy storage and user side energy storage. The corresponding types of energy storage systems include:

[0069] () Large energy storage containers used in grid-side energy storage scenarios can serve as high-quality active and reactive power regulation power sources in the grid, achieve load matching of electric energy in time and space, enhance the ability to absorb renewable energy, and are of great significance in grid system backup, relieving peak load power supply pressure, and peak and frequency regulation;

[0070] () The main operating mode of small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side and small household energy storage boxes used in home energy storage scenarios on the user side is "peak shaving and valley filling". Since there is a large price difference in electricity charges at peak and valley locations according to electricity demand, after users have energy storage equipment, in order to reduce costs, they usually charge the energy storage cabinets / boxes during the low electricity price period; during the peak electricity price period, the electricity in the energy storage equipment is discharged for use, in order to save electricity bills. In addition, in remote areas, as well as areas prone to natural disasters such as earthquakes and hurricanes, the existence of household energy storage systems is equivalent to users providing themselves and the power grid with backup power, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0071] In combination with the above-mentioned situation of storing energy by physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage system may include at least one of the above-mentioned batteries, using the chemical elements in the battery as energy storage media, so as to realize the charging and discharging process through the chemical reaction or change of the energy storage medium. In simple terms, the electric energy generated by light energy and wind energy is stored in at least one battery through the chemical reaction or change of the energy storage medium, and when the use of external electric energy reaches a peak, the electric energy stored in at least one battery is released for use through the chemical reaction or change of the energy storage medium, or transferred to a place where the electric energy is scarce for use.

[0072] In summary, the battery cell 200 serves as the smallest energy unit of the battery module, battery pack 300, and energy storage system, and a battery cell 200 has one or more cores 100. During the charging and discharging process, the core 100 shrinks and expands, so it is necessary to set a thinning area b on the edge (at least one side edge) of the core 100. The setting of the thinning area b will cause uneven force distribution on the edge and the middle of the core 100, resulting in the occurrence of edge lithium deposition. The corner gap of the curved part of the core 100 is too large, which is also prone to middle lithium deposition, reducing the cycle life of the core 100, and the inner ring 101 of the core is prone to brittle fracture, which poses a risk of internal short circuit and a safety hazard.

[0073] In other words, the core 10 is wound around the winding center a. Taking the core 10 being wound twice as an example, the portion of the core 100 adjacent to the winding center a can be defined as the core inner circle 101, and the portion away from the winding center a can be defined as the core outer circle 102. If the core 100 is wound more than two times, the innermost circle is defined as the core inner circle 101, and the outermost circle is defined as the core outer circle 102. The winding center a is the axis or plane. Therefore, a portion of the core 100 will bend during the winding process, and the portion adjacent to the winding center a in the bent portion is The distance between the anode electrode piece 11 and the cathode electrode piece 12 of the core inner ring 101 is greater than the distance between the anode electrode piece 11 and the cathode electrode piece 12 of the core outer ring 102 in the curved part away from the winding center a, which makes the corner part of the core inner ring 101 prone to lithium deposition, and the thinning area b is located on the edge area of ​​the winding core 100, which easily leads to edge lithium deposition, and the curvature of the core inner ring 101 is too small, which makes the core inner ring 101 prone to brittle fracture, and then causes internal short circuit, posing a safety hazard.

[0074] In view of this, an embodiment of the utility model provides a winding core 100, and a buffer pad 20 is arranged on the winding center a. The winding core 100 is wound around the buffer pad 20, which can not only balance the expansion force generated by the winding core 100 during the charging and discharging process and improve the edge lithium deposition, but also support the core inner ring 101 through the buffer pad 20, reduce the corner gap of the core inner ring 101, so as to improve the middle lithium deposition and enhance the cycle life and reliability of the winding core 100. At the same time, the curvature of the core inner ring 101 can be increased to prevent the brittle fracture of the pole piece of the core inner ring 101, reduce the probability of internal short, reduce safety hazards, and improve working stability.

[0075] The technical solution described in the embodiment of the present utility model is applicable to the battery pack 300 and the electric device 400 using the battery pack 300 .

[0076] The power-consuming device 400 may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.; the electric toy includes 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 electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc. The embodiment of the utility model does not impose any special restrictions on the above-mentioned power-consuming device 400.

[0077] For the convenience of description, the following embodiments are described by taking the electric device 400 as a vehicle as an example.

[0078] Please refer to the figure, Figure 1 The schematic diagram of the structure of the vehicle provided by some embodiments of the utility model. The interior of the vehicle is provided with a battery pack 300, and the battery pack 300 can be arranged at the bottom, head or tail of the vehicle. The battery pack 300 can be used for power supply of the vehicle, for example, the battery pack 300 can be used as the operating power supply of the vehicle.

[0079] The vehicle may further include a controller 500 and a motor 600 . The controller 500 is used to control the battery pack 300 to supply power to the motor 600 . The motor 600 serves as a load, for example, to meet the power requirements for starting, navigating and driving the vehicle.

[0080] In some embodiments of the present invention, the battery pack 300 can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0081] Please refer to the figure, Figure 2 The exploded view of the battery pack 300 provided in some embodiments of the present invention. The battery pack 300 includes a battery cell 200 and a box 700 , and the box 700 is used to accommodate the battery cell 200 .

[0082] Among them, the box body 700 is a component for accommodating the battery cell 200, and the box body 700 provides a placement space for the battery cell 200. The box body 700 can adopt a variety of structures. In some embodiments, the box body 700 may include a tray and a box body 700, and the tray and the box body 700 cover each other to define a placement space for accommodating the battery cell 200. The tray and the box body 700 can be in various shapes, such as a cuboid, a cylinder, etc. The tray can be a hollow structure with one side open, and the box body 700 can also be a hollow structure with one side open. The open side of the box body 700 covers the open side of the tray, so as to form a box body 700 with a placement space. It can also be that the tray is a hollow structure with one side open, the box body 700 is a plate-like structure, and the box body 700 covers the open side of the tray, so as to form a box body 700 with a placement space. As an example, the battery cell 200 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes, and the utility model has no special restrictions.

[0083] In the battery pack 300, there can be one or more battery cells 200. If there are more than one battery cell 200, the multiple battery cells 200 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 200 are both connected in series and in parallel. Multiple battery cells 200 can be connected in series, in parallel, or in mixed connection to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 700. Alternatively, all battery cells 200 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by all battery cells 200 is accommodated in the box 700.

[0084] Reference below Figure 1-Figure 8 A battery cell 200 , a battery pack 300 , an energy storage system, and an electric device 400 according to an embodiment of the present invention are described.

[0085] like Figure 3 As shown, according to a battery cell 200 according to an embodiment of the present invention, the battery cell 200 includes a winding core 100 and a shell 210 .

[0086] Among them, the shell 210 has a accommodating cavity, the core 100 is arranged in the accommodating cavity, and the core 100 includes: a core body 10 and a buffer pad 20. The core body 10 is wound around a winding center a, and has a center hole at the winding center. The core body 10 has a thinning zone b and an intermediate zone c arranged in sequence along the winding axis. The pole piece thickness of the thinning zone b is less than the pole piece thickness of the intermediate zone c. The buffer pad 20 is arranged in the center hole. The buffer pad 20 includes an intermediate portion 21 and a supporting portion 22 arranged in sequence along the winding axis. The supporting portion 22 is arranged corresponding to the thinning zone b of the core body 10, and the intermediate portion 21 is arranged corresponding to the intermediate zone c, and the radial thickness of the support portion 22 in the winding direction is greater than the sum thickness of the intermediate portion 21 in the winding radial direction.

[0087] Specifically, the buffer pad 20 can be generally cylindrical or flat, and the buffer pad 20 is arranged on the winding center a, and the core body 10 can be arranged around the buffer pad 20, such as around two or more circles, the innermost circle that fits the buffer pad 20 is the core inner circle 101, and the outermost circle away from the buffer pad 20 is the core outer circle 102, and the multiple circles between the core outer circle 102 and the core inner circle 101 can be defined as the core middle circle 103, the core body 10 has two ends opposite to each other in the winding axis, and a thinning area b is formed on at least one of the two ends, and the support part 22 has a support part 22 and an intermediate part 21 arranged in sequence in the winding axis, the support part 22 is arranged corresponding to the thinning area b to support the thinning area b of the core body 10, and the intermediate part 21 is arranged corresponding to the intermediate area c to support the intermediate area c of the core body 10, and the buffering protection of the core body 10 can be achieved by the support part 22 and the intermediate part 21.

[0088] It should be pointed out that a buffer pad 20 is added to the winding center a, and the thinning area b is elastically supported by the support part 22, and the middle part 21 elastically supports the middle area c. This can prevent the inner circle electrode (the electrode part in the area where the inner circle 101 of the core is located) from brittle fracture after the core 100 is hot pressed, and can improve the inner circle corner gap, balance the expansion force generated by the core 100 during charging and discharging, prevent lithium deposition at the edge, and reduce the inner circle corner gap. This can improve lithium deposition on the inner circle electrode and reduce the risk of lithium deposition caused by excessive inner circle corner gap, thereby improving cycle life and reliability.

[0089] It can be understood that the buffer pad 20 is arranged on the inner ring 101 of the core, which can increase the curvature of the inner ring to prevent the brittle fracture of the inner ring electrode, prevent the risk of internal short caused by the brittle fracture of the inner ring, and reduce safety hazards. The setting of the buffer pad 20 can also make the inner ring electrode (inner ring anode electrode and inner ring cathode electrode) more compact, effectively reduce the inner ring corner gap to reduce lithium plating in the inner ring, and at the same time, the force uniformity of the thinning area b and the middle area c is better, which can also improve the edge lithium plating, thereby improving the cycle life and reliability of the core 100.

[0090] According to the battery cell 200 of the embodiment of the utility model, by providing a buffer pad 20, and making the larger supporting part 22 correspond to the thinned area b, and the smaller middle part 21 correspond to the middle area c, the force can be balanced to prevent lithium deposition at the edge, and at the same time support the inner circle pole piece, reduce the inner circle corner gap, improve the inner circle lithium deposition, so as to reduce the probability of lithium deposition on the core 100, improve the cycle life and reliability of the core 100, and at the same time reduce the probability of brittle fracture of the inner circle pole piece, reduce the probability of internal short, and reduce safety hazards.

[0091] like Figure 7 and Figure 8As shown, the battery cell 200 according to the embodiment of the present invention includes: a housing 210 and the winding core 100 in the above embodiment, and the winding core 100 is disposed in the housing 210 .

[0092] Specifically, the shell 210 is provided with an assembly cavity, and the core 100 can be one or more. One or more cores 100 are arranged in the assembly cavity, and each core 100 is provided with the above-mentioned buffer pad 20, or at least one core 100 is provided with the above-mentioned buffer pad 20, which can reduce the gap between the shell 210 and the core 100, and the buffer pad 20 can expand or contract to balance the expansion and contraction generated during the charging and discharging process of the battery cell 200, thereby improving the stability and reliability of the battery cell 200.

[0093] It should be pointed out that the probability of lithium deposition and internal short circuit in the winding core 100 of the battery cell 200 is lower, which can also reduce the potential safety hazard of the battery cell 200 and improve the working stability and reliability of the battery cell 200.

[0094] It is understandable that the battery cell 200 of the embodiment of the utility model is not limited thereto, and the above-mentioned buffer pad 20 may be arranged between adjacent winding cores 100 and between the winding core 100 and the shell 210 to achieve the technical effect of balancing the expansion force.

[0095] It should be pointed out that the winding axial direction may be the length direction, and the winding radial direction may be the width direction.

[0096] See also Figure 4 , Figure 5 and Figure 6 As shown, according to some embodiments of the present invention, the size of the support portion 22 in the winding radial direction gradually decreases in the direction toward the middle portion 21 .

[0097] That is, in the direction toward the middle portion 21 , the width dimension of the support portion 22 gradually decreases, and the oblique side of the support portion 22 is formed as the length edge of the support portion 22 , and the length edge is smoothly transitioned.

[0098] In this way, on the one hand, the support portion 22 whose size gradually decreases in the winding radial direction can match the thinning area b to improve the supporting effect on the thinning area b. On the other hand, the smoothly transitioning length edge can prevent scratches on the pole piece or diaphragm 13, thereby improving the stability and reliability of the winding core 100, and further improving the stability and reliability of the battery cell 200.

[0099] Combination Figure 2 , Figure 3 and Figure 4 As shown, the angle formed between the length edge of the support portion 22 and the winding axis is 0° to 60°.

[0100] It should be pointed out that the range values ​​of 0° and 60° defined in the embodiment of the present utility model do not include the 0° endpoint, but include the 60° endpoint, that is, the included angle is α, 0°<α≤60°.

[0101] In this way, the thickness of the support part 22 can be made more reasonable, preventing the edge area of ​​the support part 22 from being too thick, causing the force on the edge to be greater than the force on the middle area c, thereby improving the mechanical balance effect, effectively improving edge lithium deposition, and extending the cycle life and working stability.

[0102] Furthermore, the angle formed between the length edge of the support portion 22 and the winding axis is 0° to 45°.

[0103] In other words, 0°<α≤45°, the thickness of the end of the support portion 22 away from the middle portion 21 is more reasonable, the improvement effect of edge lithium deposition is better, and the overall space occupied by the buffer pad 20 is smaller, and the arrangement of the core 100 can be more compact.

[0104] In some embodiments, the size of the middle portion 21 in the winding radial direction is 0.5 mm to 3 mm.

[0105] Exemplarily, the width dimension of the middle portion 21 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, etc. Any value within the range of 0.5 mm to 3 mm, including the endpoint values, is an optional width dimension value of the middle portion 21 of the present invention.

[0106] In this way, on the one hand, the width of the middle part 21 can be prevented from being too small to maintain the elastic support and cushioning effect of the middle part 21. On the other hand, the width of the middle part 21 can be prevented from being too large, which reduces material costs while taking into account the space occupied by the cushion pad 20.

[0107] like Figure 4 As shown, in some embodiments, the maximum dimension of the support portion 22 in the winding radial direction is W1, the dimension of the middle portion 21 in the winding radial direction is W2, and 1<W1 / W2≤2 is satisfied.

[0108] Exemplarily, the maximum width dimension of the support portion 22 may be 1.1 times, 1.2 times, 1.5 times, 2 times, etc., of the width dimension of the middle portion 21 .

[0109] Thus, while making the support portion 22 fit more closely with the thinning area b to improve the support and buffering effects, the size of the support portion 22 can also be taken into account to prevent the support portion 22 from being too large, thereby reducing material costs and taking into account the space occupied by the winding core 100 to reduce the difficulty of layout.

[0110] According to some embodiments of the present invention, the size of the support portion 22 in the winding axial direction is greater than or equal to the size of the thinned area b in the winding axial direction.

[0111] In this way, the length of the support portion 22 is greater than or equal to the length of the thinning zone b, so that the thinning zone b can be located in the area where the support portion 22 is located, so that the difference between the width dimension of the thinning zone b and the width dimension of the middle zone c is smaller, the flatness is higher, the force distribution is more uniform, the edge lithium deposition inhibition effect is better, and the expansion force balance effect is better.

[0112] like Figure 5 and Figure 6 As shown, in some embodiments, the buffer pad 20 further includes: an extension portion 23 , and the extension portion 23 is located at one end of the support portion 22 away from the middle portion 21 .

[0113] In this way, a certain assembly margin can be reserved by the extension portion 23 to reduce the assembly accuracy requirement of the winding core 100. Even if the thickest position of the support portion 22 is not aligned with the thinning area b, the support and buffering effect of the support portion 22 can be maintained to improve assembly efficiency.

[0114] Combination Figure 4 , Figure 5 and Figure 6 As shown, in some embodiments, the number of the support portions 22 is consistent with the number of the thinned regions b, and the support portion 22 is formed at at least one end of the middle portion 21 .

[0115] It should be pointed out that different cutting methods of the core 10 will result in different numbers of thinning zones b. For the middle-cut pole piece, there is only one thinning zone b, and correspondingly, the support portion 22 can be set only at one end of the middle portion 21. In the embodiment where the core 10 is edge-cut, support portions 22 need to be set at both ends of the middle portion 21.

[0116] like Figure 2 As shown, a battery pack 300 according to an embodiment of the present invention includes: a battery cell 200 in the above embodiment.

[0117] The energy storage system according to the embodiment of the present utility model includes: the battery pack 300 in the above embodiment.

[0118] like Figure 1 As shown, the electric device 400 according to the embodiment of the utility model includes: the battery pack 300 in the above embodiment.

[0119] According to the battery cell 200 of the embodiment of the utility model, the winding core 100 includes a core body 10 and a buffer pad 20, and the buffer pad 20 is arranged on the winding center a of the winding core 100, and the buffer pad 20 includes a support portion 22 and a middle portion 21 which are arranged in sequence in the winding axis direction, and the support portion 22 is arranged at both ends or at least one end of the middle portion 21, and a thinning area b is arranged on one side edge or both side edges of the core body 10 in the winding axis direction, the support portion 22 is arranged corresponding to the thinning area b, and the middle portion 21 is arranged corresponding to the middle area c, and the size of the support portion 22 in the winding radial direction is larger than the size of the middle area c in the winding radial direction, so as to improve edge lithium deposition and internal lithium deposition, extend the cycle life, improve stability, and also can increase the curvature of the inner ring pole piece, reduce the probability of internal short, so as to reduce safety hazards and improve safety of use.

[0120] Other structures and operations of the winding core 100, the battery cell 200, the battery pack 300, the energy storage system and the electrical device 400 according to the embodiment of the utility model are known to ordinary technicians in the field and will not be repeated here.

[0121] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0122] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: A housing (210), wherein the housing (210) has a receiving cavity; A winding core (100), the winding core (100) is arranged in the accommodating cavity, the winding core (100) comprises: a core body (10) and a buffer pad (20), the core body (10) is arranged in the accommodating cavity, the core body (10) is wound around a winding center (a), and the winding center has a center hole, the core body (10) has a thinning area (b) and a middle area (c) arranged in sequence along the winding axis, the pole piece thickness of the thinning area (b) is less than the pole piece thickness of the middle area (c), the buffer pad (20) is arranged in the center hole, the buffer pad (20) comprises a middle part (21) and a supporting part (22) arranged in sequence along the winding axis, the supporting part (22) is arranged corresponding to the thinning area (b), the middle part (21) is arranged corresponding to the middle area (c), and the thickness of the supporting part (22) in the winding radial direction is greater than the thickness of the middle part (21) in the winding radial direction.

2. The battery cell according to claim 1, characterized in that: In the direction toward the middle portion (21), the dimension of the support portion (22) in the winding radial direction gradually decreases.

3. The battery cell according to claim 2, characterized in that: The angle formed between the length edge of the support portion (22) and the winding axis is 0° to 60°.

4. The battery cell according to claim 3, characterized in that: The angle formed between the length edge of the support portion (22) and the winding axis is 0° to 45°.

5. The battery cell according to any one of claims 2 to 4, characterized in that: The dimension of the middle portion (21) in the winding radial direction is 0.5 mm to 3 mm.

6. The battery cell according to any one of claims 2 to 4, characterized in that: The maximum dimension of the support portion (22) in the winding radial direction is W1, the dimension of the middle portion (21) in the winding radial direction is W2, and 1<W1 / W2≤2 is satisfied.

7. The battery cell according to any one of claims 2 to 4, characterized in that: The dimension of the support portion (22) in the winding axial direction is greater than or equal to the dimension of the thinned area (b) in the winding axial direction.

8. The battery cell according to any one of claims 1 to 4, characterized in that: The buffer pad (20) further comprises an extension portion (23), wherein the extension portion (23) is located at an end of the support portion (22) away from the middle portion (21).

9. The battery cell according to any one of claims 1 to 4, characterized in that: The number of the supporting portions (22) is consistent with the number of the thinned areas (b), and the supporting portion (22) is formed at at least one end of the middle portion (21).

10. A battery pack, characterized in that: include: The battery cell according to any one of claims 1 to 9.

11. An energy storage system, characterized in that: include: The battery pack according to claim 10.

12. An electrical device, characterized in that: include: The battery pack according to claim 10.

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