Battery and energy storage equipment

Abstract

The embodiment of the utility model provides a battery and energy storage equipment, and relates to the technical field of energy storage, the battery comprises a shell and a battery cell accommodated in the shell, a support piece is arranged between a positive plate and a diaphragm at the corner of the battery cell, so that a gap is formed between the positive plate and the diaphragm, or a support piece is arranged between a negative plate and the diaphragm at the corner of the battery cell, so that the gap is formed between the negative plate and the diaphragm. By forming the gaps at the corners, the problem of heat accumulation caused by too large stress at the corners after the battery cell expands can be effectively solved, so that the probability of thermal runaway of the battery cell can be effectively reduced, and the spreading chain reaction of thermal runaway can be effectively prevented when the battery cell is in thermal runaway; and the safety performance of the battery is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and in particular to a battery and an energy storage device. BACKGROUND

[0002] In related technologies, the winding type battery cell will swell as the use time increases. In particular, the corner of the battery cell has a large curvature, so that the mechanical stress on the corner of the battery cell after swelling is more concentrated, and heat is more easily accumulated and cannot be effectively released, thereby resulting in poor heat dissipation effect of the corner of the battery cell and high risk of thermal runaway of the battery cell. CONTENT OF THE UTILITY MODEL

[0003] Embodiments of the present application provide a battery and an energy storage device to improve the heat dissipation capacity of the corner of the battery cell, reduce or prevent the risk of thermal runaway of the battery cell, and improve the safe use performance of the battery cell.

[0004] In a first aspect, embodiments of the present application provide a battery. The battery includes a shell, a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet, which are accommodated in the shell. The positive electrode sheet, the separator, and the negative electrode sheet are wound to form a battery cell. The battery includes a length direction, a width direction, and a height direction. The height direction of the battery is perpendicular to the winding direction of the battery cell. The battery further includes a support member provided at a corner of the battery cell. The support member is located between the positive electrode sheet and the separator, or the support member is located between the negative electrode sheet and the separator. The extension direction of the support member is consistent with the height direction of the battery. Along the winding direction of the battery cell, the two sides of the support member form a gap. The gap extends to the top surface or the bottom surface of the battery cell in the height direction of the battery. Specifically, the gap is formed by the positive electrode sheet and the separator located on both sides of the support member, or the gap is formed by the negative electrode sheet and the separator located on both sides of the support member.

[0005] In the present embodiment, the support member is provided between the positive electrode sheet and the separator, or the support member is provided between the negative electrode sheet and the separator, which can bring the desired effect of the present embodiment, and the principles of the two are similar. Hereinafter, how the support member provided between the positive electrode sheet and the separator brings the desired effect will be mainly introduced, and the effect brought by the support member provided between the negative electrode sheet and the separator can be referred to the effect brought by the support member provided between the positive electrode sheet and the separator.

[0006] Because a support structure is provided between the positive electrode and the separator at the corner, a gap is formed between them. This allows the positive electrode to directly contact the gas in the gap, enabling rapid heat exchange. The gap extends to the top or bottom surface of the cell along the battery's height, allowing for rapid airflow between the gas in the gap and the gas outside the cell, thus achieving rapid heat dissipation. Specifically, the heat generated by the cell is mainly transferred along the surface of the positive electrode. When the heat reaches the gap at the corner, it can quickly dissipate through the gas in the gap, effectively improving the cell's heat dissipation capacity. Because heat dissipates rapidly at the corner gap, heat cannot accumulate at the corner, effectively reducing the probability of thermal runaway caused by heat accumulation at the corner.

[0007] In addition, even if thermal runaway occurs at a certain location in the cell, the large amount of heat generated by the thermal runaway is transferred to the gap location along with the surface of the positive electrode. The heat can be quickly dissipated with the gas in the gap, thereby rapidly reducing the temperature of the cell. This can effectively reduce the propagation speed of thermal runaway in the cell, and can even effectively prevent the propagation chain reaction of thermal runaway in the cell, thus greatly improving the safety performance of the battery.

[0008] In addition, the gaps formed at the corners of the battery cell can effectively reduce heat transfer in the radial direction of the battery cell.

[0009] In some embodiments, the two ends of the support extend to the two ends of the cell in the height direction of the battery, and the gap penetrates the top and bottom surfaces of the cell in the height direction of the battery. Because the gap penetrates the cell in the height direction of the battery, the flow of gas within the gap and gas outside the cell can be improved, which can effectively prevent heat from accumulating at corner positions, thereby effectively reducing the risk of battery thermal runaway.

[0010] In some embodiments, the battery cell includes a square body and corners located on both sides of the body in the width direction of the battery. The curvature of the positive electrode, separator, and negative electrode at the corner is greater than that of the positive electrode, separator, and negative electrode at the body. The support is located at the middle position of the corner in the winding direction of the battery cell. Since the middle position of the corner is basically the position with the greatest curvature, it is also the position where heat is most likely to accumulate. In this embodiment, placing the support at the middle position of the corner in the winding direction of the battery cell can effectively improve the heat dissipation capacity at the middle position where heat is most likely to accumulate, thereby reducing the probability of thermal runaway at the corner of the battery cell and improving the safety performance of the battery cell.

[0011] In some embodiments, the support is located at a middle position of the corner in the winding direction of the battery cell, the direction in which the positive electrode sheet, the separator and the negative electrode sheet are stacked is the radial direction of the battery cell, and the size of the position farther from the support in the radial direction of the battery cell is smaller along the winding direction of the battery cell. The middle position of the corner is usually the position with the largest curvature of the battery cell. By locating the support at the middle position of the corner, the size of the position farther from the middle position of the corner in the radial direction of the battery cell is smaller, and the curvature of the position farther from the middle position of the corner is smaller, so the probability of heat accumulation is lower. Therefore, it is more reasonable to locate the support at the middle position of the corner, and the number of supports can be effectively reduced to some extent while meeting the heat dissipation requirement.

[0012] In some embodiments, the positive electrode sheet and the separator at the corner are both multi-layered, and the support is arranged between the multi-layered positive electrode sheet and the adjacent separator. Since the support is arranged between the multi-layered positive electrode sheet and the adjacent separator at the corner, each layer of the positive electrode sheet of the battery cell can form a gap with the adjacent separator, and can timely release heat, thereby improving the overall heat dissipation capacity of the battery cell. It can be understood that in other embodiments, the support can also be arranged between part of the positive electrode sheets and the separators, for example, a support can be arranged every X layers of positive electrode sheets, where X is 1-10.

[0013] In some embodiments, the support has a cylindrical structure, the axial direction of the support is consistent with the height direction of the battery, and the axial size of the support is consistent with the height direction of the battery cell. Since the support has a cylindrical structure, the processing difficulty of the support can be effectively reduced. In addition, since the support has a cylindrical structure, the position where the support contacts the positive electrode sheet or the negative electrode sheet is a curved surface, thereby effectively reducing the damage to the positive electrode sheet or the negative electrode sheet under high stress. It can be understood that in other embodiments, the support can also have other long strip structures.

[0014] In some embodiments, a plurality of supports are arranged between the positive electrode sheet and the separator along the winding direction of the battery cell. Since a plurality of supports are arranged between the positive electrode sheet and the separator along the winding direction of the battery cell, gaps can be formed at multiple positions of the corner in the winding direction of the battery cell, thereby improving the heat exchange effect of the positive electrode sheet at the corner and the gas in the gap, and improving the heat dissipation capacity of the corner.

[0015] In some embodiments, the support has a long strip structure, and the size of the positive electrode sheet at the corner in the winding direction of the battery cell is greater than the size of the support in the winding direction of the battery cell. Since the size of the positive electrode sheet at the corner in the winding direction of the battery cell is greater than the size of the support in the winding direction of the battery cell, when the support is arranged between the positive electrode sheet and the separator, the support will not completely cover the positive electrode sheet at the corner, thereby forming a gap between the positive electrode sheet at the corner and the separator, and improving the heat dissipation capacity of the corner of the battery cell.

[0016] In some embodiments, the metal cations within the cell can pass through the support. Since the metal cations within the cell can pass through the support, the inclusion of the support within the cell does not affect the normal flow path of the metal cations and therefore does not affect the normal performance of the cell.

[0017] In some embodiments, the support and the separator are made of the same material and are integrally formed. Because the support and the separator are made of the same material, it is convenient to integrally form the separator and the support, and it can also save the connection process between the support and the separator or the electrode, thereby reducing the difficulty of the cell manufacturing process.

[0018] In some embodiments, the radial thickness of the support member in the cell is 1μm-50μm. Having the radial thickness of the support member within this range not only avoids lithium and sodium deposition problems caused by excessively large gaps in the radial direction of the cell, which would prevent electrolyte adsorption, but also effectively ensures that the gap between the positive electrode and the separator is maintained within the required size range to achieve the desired heat dissipation.

[0019] Secondly, embodiments of this application also provide an energy storage device, which includes a housing and a battery as described in any of the first aspects above, with the battery disposed inside the housing. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0021] Figure 1 This is a schematic diagram of the structure of a battery pack provided in an embodiment of this application;

[0022] Figure 2 This is a schematic diagram of the structure of a battery provided in an embodiment of this application;

[0023] Figure 3 for Figure 2 A cross-sectional view of some of the battery cells in the embodiment;

[0024] Figure 4 for Figure 2 A schematic cross-sectional view of some of the battery cells in the embodiment;

[0025] Figure 5 for Figure 4 A magnified view of a portion of point A in the middle;

[0026] Figure 6 for Figure 2 A schematic cross-sectional view of some of the battery cells in the embodiment;

[0027] Figure 7 for Figure 6A local enlarged view of the embodiment at B;

[0028] Figure 8 For Figure 6 A structural schematic view of the support in the embodiment.

[0029] Explanation of reference signs:

[0030] 1, battery pack; 2, shell; 3, battery;

[0031] 10, shell;

[0032] 20, battery cell; 201, gap; 21, main body; 22, corner; 23, positive electrode sheet; 24, negative electrode sheet; 25, separator; 26, support. DETAILED DESCRIPTION

[0033] The following first explains some terms related to the embodiments of the present application.

[0034] In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] In this specification, the explanation of the terms such as "vertical".

[0036] Vertical: The vertical defined in the present application is not limited to the absolute vertical intersection (the angle is 90 degrees) relationship, and allows the relationship that is not an absolute vertical intersection due to factors such as assembly tolerance, design tolerance, and structure flatness, and allows the existence of a small angle range of error, for example, within the assembly error range of 80 degrees to 100 degrees, which can be understood as a vertical relationship.

[0037] In modern society, there are a large number of devices that rely on electricity to operate, from household appliances to data centers, factory production lines, and power supply has become one of the factors to maintain the normal operation of modern society. Therefore, energy storage devices have developed rapidly and are widely used, such as battery packs, energy storage cabinets using battery packs, uninterruptible power supply cabinets, and even vehicles using battery packs. Energy storage devices can be used to store electrical energy and to power devices that need to operate on electricity. Energy storage devices can be applied in the fields of site energy, photovoltaic, household energy storage, commercial and industrial energy storage, and large ground power station energy storage.

[0038] With the development of energy storage devices, high-energy-density energy storage devices have been more and more widely favored, and are also the direction that needs to be developed. However, high-energy-density energy storage devices have problems such as low charging and discharging efficiency, lithium or sodium precipitation caused by poor electrolyte infiltration, which also leads to the reduction of the service life of the energy storage device and poor user experience.

[0039] Therefore, the embodiments of the present application provide a high-service-life and good-user-experience energy storage device, such as an energy storage device. Figure 1 Figure 1 The battery pack 1 in the embodiments is taken as an example. The battery pack 1 includes a shell 2 and a plurality of batteries 3 arranged in the shell 2. The plurality of batteries 3 are arranged in the shell 2 to store or release electrical energy.

[0040] In order to reduce the risk of thermal runaway of the battery pack 1 and improve the service life of the battery pack 1, the battery pack 1 in the embodiments changes the structure of the battery 3 to improve the heat dissipation performance of the corner of the battery 3 and improve the stress concentration problem at the corner of the battery, thereby reducing the risk of thermal runaway of the battery 3 and improving the service life of the battery 3, so as to achieve the purpose of reducing the risk of thermal runaway of the battery pack 1 and improving the service life of the battery pack 1.

[0041] Figure 2 A structural schematic diagram of a battery is provided in the embodiments of the present application, Figure 2 The battery in the embodiments is a schematic diagram after removing the top cover.

[0042] Referring to Figure 2 The battery 3 includes a shell 10 and an electric core 20 arranged in the shell 10. The electric core 20 is a winding type electric core, that is, the electric core 20 is formed by winding a positive plate, a diaphragm and a negative plate.

[0043] For the convenience of the following description, the battery 3 includes a height direction Z, a width direction X and a thickness direction Y. The height direction Z is the Z direction in the drawing, the width direction X is the X direction in the drawing, the thickness direction Y is the Y direction in the drawing, and the winding direction R of the electric core 20 is the R direction in the drawing. The Z direction is perpendicular to the R direction.

[0044] Referring to Figure 2 ​, the corner 22 is substantially semicircular. The battery 3 in the embodiment mainly ensures that the gap between the positive plate and the separator or the gap between the negative plate and the separator at the corner 22 is always greater than a preset limit value during use of the battery 3, that is, the gap between the positive plate and the separator or the gap between the negative plate and the separator is always large enough. Specifically, after the battery 3 is used for a period of time, even if swelling occurs at the corner 22, the gap between the positive plate and the separator or the gap between the negative plate and the separator at the corner 22 is still large enough, so that the positive plate and the separator or the negative plate and the separator at the corner 22 are not pressed due to swelling, and the positive plate and the separator or the negative plate and the separator at the corner 22 do not generate a large pressure, thereby avoiding the problem of cracking of the positive plate or the negative plate due to excessive stress, and avoiding the problem of metal cation precipitation, such as lithium precipitation for a lithium battery or sodium precipitation for a sodium ion battery. In addition, since the gap between the positive plate and the separator or the gap between the negative plate and the separator is still large enough after being used for a period of time, the heat dissipation problem at the corner 22 can be ensured, and the probability of thermal runaway is reduced. The cell 20 in the embodiment can effectively reduce the probability of thermal runaway at the corner 22, improve the service life, and the corner 22 of the cell 20 is relatively the part with a lower service life and a higher risk of thermal runaway, so that the cell 20 in the embodiment can effectively reduce the probability of thermal runaway at the corner 22 to improve the service life and safety performance of the cell 20, so that the battery 3 in the embodiment can effectively reduce the probability of thermal runaway and improve the service life.

[0045] Figure 3 For Figure 2 A cross-sectional view of part of the cell 20 in the embodiment.

[0046] Referring to Figure 3 , the cell 20 includes a positive plate 23, a negative plate 24, and a separator 25 located between the positive plate 23 and the negative plate 24, as shown in the accompanying drawings. Figure 3 The positive plate 23, the negative plate 24, and the separator 25 at the corner 22 are substantially semicircular, the positive plate 23, the negative plate 24, and the separator 25 of the main body 21 are substantially planar, the positive plate 23, the negative plate 24, and the separator 25 at the corner 22 are stacked and have a plurality of numbers, and the corner 22 is substantially semicircular. The positive plate 23, the negative plate 24, and the separator 25 of the main body 21 are stacked and have a plurality of numbers, and the main body 21 is substantially square.

[0047] It is understood that the main body 21 and the corner 22 are integrated, that is, the positive electrode 23 of the corner 22 and the positive electrode 23 of the main body 21 are integrated, the negative electrode 24 of the corner 22 and the negative electrode 24 of the main body 21 are integrated, and the separator 25 of the corner 22 and the separator 25 of the main body 21 are integrated. In this embodiment, the cell 20 is divided into the main body 21 and the corner 22 in order to more clearly distinguish the corner 22 and the main body 21. The curvature of the positive electrode 23, negative electrode 24 and separator 25 of the corner 22 part is greater than that of the positive electrode 23, negative electrode 24 and separator 25 of the main body 21 part. Specifically, the curvature of the positive electrode 23, negative electrode 24 and separator 25 of the corner 22 part is greater than 0, while the curvature of the positive electrode 23, negative electrode 24 and separator 25 of the main body 21 part is approximately 0.

[0048] Reference Figure 3 The battery 3 also includes a support member 26, which is disposed between the positive electrode 23 and the separator 25 at the corner 22. In this embodiment, by disposing of the support member 26 between the positive electrode 23 and the separator 25 at the corner 22, a gap 201 is formed between the positive electrode 23 and the separator 25 at the corner 22. Specifically, the gap 201 is located on both sides of the support member 26 in the winding direction R of the cell 20. Figure 3 Only a portion of cell 20 is shown, thus it can only be seen in Figure 3 As seen in the diagram, a gap 201 is formed on one side of the support member 26. In this embodiment, due to the supporting effect of the support member 26, a gap 201 is formed between the positive electrode plate 23 and the separator 25 at the corner 22. Moreover, under the action of the support member 26, after the cell 20 expands, the gap 201 between the positive electrode plate 23 and the separator 25 can still be maintained within the required size range. This ensures rapid heat exchange between the positive electrode plate 23 and the gas in the gap 201 after the cell 20 expands, achieving rapid heat dissipation and effectively improving the heat dissipation capacity of the positive electrode plate 23 at the corner 22. For example, when heat in the cell 20 is transferred along the surface of the positive electrode plate 23 to the gap 201 at the corner 22, the presence of the gap 201 at the corner 22 allows the positive electrode plate 23 at the gap 201 to rapidly exchange heat with the gas in the gap 201, achieving rapid heat dissipation and effectively improving the overall heat dissipation efficiency of the cell 20. Moreover, due to the presence of gap 201, heat will not accumulate at corner 22, thus effectively preventing heat accumulation at corner 22, where cell 20 is most likely to accumulate heat, thereby effectively reducing the probability of thermal runaway of cell 20.

[0049] In addition, even if a short circuit or thermal runaway occurs at a certain position of the positive tab 23 of the battery cell 20, the heat generated by the thermal runaway spreads to the gap 201 at the corner 22 of the positive tab 23, and the heat can be quickly dissipated through the gap 201, thereby avoiding further spread of the heat along the positive tab 23, so as to effectively reduce the spread speed of the thermal runaway, and even block the chain reaction of the thermal runaway.

[0050] In addition, since there is a gap 201 between the positive tab 23 and the diaphragm 25 at the corner 22, when thermal runaway occurs at the corner 22, the heat can be effectively prevented from being transmitted in the radial direction of the battery cell 20, and the heat can be effectively reduced to the positive tab 23 or the negative tab 24 of other layers, so as to avoid thermal runaway of the adjacent positive tab 23 or negative tab 24. It should be noted that the radial direction of the battery cell 20 is the direction of the stacking of the positive tab 23, the diaphragm 25 and the negative tab 24.

[0051] It can be understood that the main way of heat transfer of the battery cell 20 is along the surface of the positive tab 23 or the negative tab 24, and the second way is to conduct heat to the adjacent tab in the direction perpendicular to the positive tab 23 or the negative tab 24 (i.e. the radial direction of the battery cell 20). The battery cell 20 in the embodiment can not only effectively limit the heat conduction along the surface of the positive tab 23 or the negative tab 24 when thermal runaway occurs, but also effectively limit the heat conduction to the adjacent tab in the direction perpendicular to the positive tab 23 or the negative tab 24.

[0052] Referring to Figure 3 In some embodiments, a support 26 can also be provided between the negative tab 24 and the diaphragm 25 at the corner 22 to leave a gap 201 between the negative tab 24 and the diaphragm 25 at the corner 22, and the gap 201 is formed on both sides of the support 26 in the winding direction R of the battery cell 20. Like the positive tab 23, the gap 201 between the negative tab 24 and the diaphragm 25 at the corner 22 can also improve the heat dissipation capacity of the negative tab 24 at the corner 22, and the heat is not gathered at the corner 22, so that the corner 22 of the battery cell 20 where the heat is most likely to gather can be effectively prevented from gathering heat, thereby effectively reducing the probability of thermal runaway of the battery cell 20. In addition, when thermal runaway occurs at a certain position of the negative tab 24 of the battery cell 20, the heat generated by the thermal runaway can also be quickly dissipated by being transmitted along the surface of the negative tab 24 to the gap 201, so as to effectively reduce the spread speed of the thermal runaway, and even block the chain reaction of the thermal runaway. For details, please refer to the effect of the support 26 provided between the positive tab 23 and the diaphragm 25.

[0053] Referring to Figure 3In some embodiments, the support 26 can also be arranged between the positive electrode sheet 23 and the separator 25 and between the negative electrode sheet 24 and the separator 25, so that a gap 201 is formed between the positive electrode sheet 23 and the separator 25 at the corner 22, and a gap 201 is formed between the negative electrode sheet 24 and the separator 25 at the corner 22. In this embodiment, compared with arranging the support 26 only between the positive electrode sheet 23 and the separator 25 or forming the gap 201 only between the negative electrode sheet 24 and the separator 25, the speed of heat runaway spreading can be further reduced, and the ability to block the chain reaction of heat runaway spreading can be improved.

[0054] It can be understood that the positive electrode sheet 23, the negative electrode sheet 24, and the separator 25 all have a certain strength and will not deform greatly, so that when the positive electrode sheet 23, the negative electrode sheet 24, and the separator 25 are extruded by the support 26, the positive electrode sheet 23, the negative electrode sheet 24, and the separator 25 will not deform greatly to completely cover the support 26, so that under the support of the support 26, the gap 201 can be formed between the positive electrode sheet 23 and the separator 25, or the gap 201 can be formed between the negative electrode sheet 24 and the separator 25.

[0055] Referring to Figure 3 In some embodiments, the extension direction of the support 26 is consistent with the height direction Z of the battery 3, and along the winding direction R of the battery cell 20, the two sides of the support 26 form the gap 201, and in the height direction Z of the battery 3, at least one end of the gap 201 extends to communicate with the outside of the battery cell 20, so that the gas in the gap 201 can flow with the gas outside the battery cell 20, and the heat dissipation capacity of the gap 201 at the corner 22 can be effectively improved.

[0056] Referring to Figure 3 In some embodiments, the support 26 has a cylindrical structure, the axial direction of the support 26 is consistent with the height direction Z of the battery 3, and the axial dimension of the support 26 is consistent with the dimension of the battery cell 20 in the height direction Z of the battery 3, that is, in the height direction Z of the battery 3, the two ends of the support 26 extend to the two ends of the battery cell 20, respectively, so that the two ends of the gap 201 in the Z direction can communicate with the outside of the battery cell 20, so as to improve the heat dissipation effect at the corner 22.

[0057] Referring to Figure 3In some embodiments, the support 26 is located at a middle position of the corner 22 in the winding direction R of the battery cell 20. Since the curvature of the middle position of the corner 22 is substantially the maximum curvature of the corner 22, the middle position of the corner 22 is also the position where the stress and heat are most concentrated. After the battery 3 is used for a long time, the middle position of the corner 22 is most likely to be unable to effectively dissipate heat due to excessive stress. In this embodiment, since the support 26 is arranged at the middle position of the corner 22, the middle position of the corner 22 where the stress and heat are most concentrated can be supported by the support 26. In the winding direction R of the battery cell 20, gaps 201 can be formed on both sides of the support 26, that is, gaps 201 can be formed between the positive plate 23 and the separator 25 at the corner 22, or gaps 201 can be formed between the negative plate 24 and the separator 25 at the corner 22. Therefore, the positive plate 23 or the negative plate 24 at the corner 22 can quickly exchange heat with the gas in the gap 201, so that the generated heat can be quickly dissipated. Therefore, the heat dissipation capacity of the corner 22 can be improved, the probability of thermal runaway of the battery cell 20 can be reduced, and the trend of heat spread can be reduced or prevented when thermal runaway occurs.

[0058] In some embodiments, the material of the support 26 can be the same as the material of the separator 25, such as the metal cation can pass through the separator 25, and the support 26 can be made of Al 2O3, SiO2, polyolefin film, non-woven fabric or resin material, etc. Since the material of the support 26 is the same as the material of the separator 25, the arrangement of the support 26 will not affect the normal movement path of the metal cation, and will not affect the chemical properties of the battery cell 20.

[0059] It can be understood that the support 26 can be bonded to the positive plate 23 or the negative plate 24 or the separator 25 before winding by bonding to improve the winding efficiency. Of course, in other embodiments, the support 26 can be integrally formed on the surface of the separator 25 to further simplify the processing technology. Of course, the support 26 can also be added during the winding process of the battery cell 20 to improve the accuracy of the installation position of the support 26.

[0060] In some embodiments, the size L of the support 26 in the radial direction of the battery cell 20 is 1 μm-50 μm, that is, the thickness of the support 26 in the direction in which the positive electrode sheet 23, the negative electrode sheet 24 and the separator 25 are stacked is 1 μm-50 μm, which can be 10 μm, 20 μm, 30 μm and 40 μm. When the size L of the support 26 in the radial direction of the battery cell 20 is in the range, the support 26 does not cause the gap 201 between the positive electrode sheet 23 and the separator 25 at the corner 22 to be too large, nor does it cause the gap 201 between the negative electrode sheet 24 and the separator 25 to be too large. In the range, the support 26 can effectively adsorb the electrolyte to prevent the problems of lithium or sodium precipitation, and can effectively dissipate heat. It can be understood that when the number of supports 26 is multiple, the size L of the different supports 26 in the radial direction of the battery cell 20 can be the same or different.

[0061] Referring to Figure 3 In some embodiments, multiple supports 26 can be provided between the positive electrode sheet 23 and the separator 25 at the corner 22, for example, the multiple supports 26 are provided between the positive electrode sheet 23 and the separator 25 in the winding direction R of the battery cell 20. Similarly, multiple supports 26 can be provided between the negative electrode sheet 24 and the separator 25 at the corner 22, for example, the multiple supports 26 are provided between the negative electrode sheet 24 and the separator 25 in the winding direction R of the battery cell 20. By providing multiple supports 26 in the winding direction R of the battery cell 20, multiple positions at the corner 22 can form gaps 201, thereby improving the heat dissipation capacity at the corner 22. In particular, when the size of the battery 3 is large, by providing multiple supports 26 at the corner 22, multiple positions at the corner 22 can be effectively cooled, thereby reducing the risk of thermal runaway at the corner 22. It can be understood that, since the battery cell 20 includes multiple layers of positive electrode sheets 23, separators 25 and negative electrode sheets 24 in the radial direction of the battery cell 20, multiple supports 26 can be provided between each layer of positive electrode sheet 23 and the adjacent separator 25, and the number of supports 26 between different layers of positive electrode sheet 23 and the adjacent separator 25 can be different.

[0062] Referring to Figure 4 In some embodiments, supports 26 can also be provided between the positive electrode sheet 23 and the separator 25 of the main body 21 portion to form a gap 201 between the positive electrode sheet 23 and the separator 25 of the main body 21 portion, or supports 26 can also be provided between the negative electrode sheet 24 and the separator 25 of the main body 21 portion to form a gap 201 between the negative electrode sheet 24 and the separator 25 of the main body 21 portion. Therefore, when the main body 21 portion swells in the later stage of use of the battery 3, the gap 201 between the positive electrode sheet 23 and the separator 25 of the main body 21 portion and the gap 201 between the negative electrode sheet 24 and the separator 25 of the main body 21 portion can still be maintained within the required size range, thereby improving the heat dissipation effect of the main body 21 portion and reducing the risk of thermal runaway of the main body 21 portion.

[0063] It can be understood that the electric core 20 in the embodiment mainly realizes the purpose of reducing thermal runaway by providing the support 26 at the corner 22. Whether the support 26 is additionally provided in the main body 21 part can be set according to the requirements. For example, the electric core 20 with large energy density and large stress during winding can additionally provide the support 26 in the main body 21 part. The provision or non-provision of the support 26 in the main body 21 part is within the protection scope of the battery 3 in the embodiment.

[0064] Figure 2 For Figure 5 The cross-sectional view schematic diagram of the electric core 20 in the embodiment; Figure 4 For Figure 4 The local enlarged schematic diagram at A in the embodiment.

[0065] Referring to Figure 5 and Figure 4 In the embodiment, the support 26 is only provided at the middle position of the corner 22 in the winding direction R. Along the winding direction R of the electric core 20, the position of the gap 201 farther away from the support 26 has a smaller size in the radial direction of the electric core 20. Since the support 26 is located at the middle position of the corner 22, which is also the position with the largest curvature. The farther away from the middle position of the corner 22, the smaller the curvature, that is, the closer to the main body 21, the smaller the stress concentration problem, and thus the better heat dissipation at the position of the corner 22 closer to the main body 21 part. Therefore, the provision of the support 26 only at the middle position of the corner 22 in the winding direction R in the embodiment not only meets the heat dissipation requirement, but also effectively reduces the number of supports 26, and reduces the processing cost and process difficulty.

[0066] Referring to Figure 5 and Figure 4 The support 26 is only provided between the positive plate 23 and the diaphragm 25 at the corner 22. Since the positive material contains an oxidizing agent, it is easy to decompose under high temperature conditions, and thus the probability of thermal runaway caused by the positive plate 23 is relatively high. The provision of the support 26 between the positive plate 23 and the diaphragm 25 at the corner 22 can effectively improve the problem that the thermal runaway is more likely to occur at the positive plate 23. The reduction of the probability of thermal runaway caused by the positive plate 23 can greatly reduce the probability of thermal runaway of the electric core 20. Moreover, the number of supports 26 provided between the negative plate 24 and the diaphragm 25 can be saved, thereby reducing the processing cost and process difficulty.

[0067] Referring to Figure 5 and Figure 4, the positive electrode sheet 23, the negative electrode sheet 24 and the separator 25 of the winding completed battery cell 20 all have multiple layers, and the support 26 is arranged between the multiple layers of the positive electrode sheet 23 and the adjacent separator 25 at the corner 22, so that each layer of the positive electrode sheet 23 in the radial direction of the battery cell 20 can form a gap 201 at the position of the corresponding support 26, so as to ensure that each layer of the positive electrode sheet 23 can be quickly cooled, avoid heat concentration, reduce the risk of thermal runaway of the battery cell 20, and improve the safety performance of the battery 3. In addition, in the embodiment, the positive electrode sheet 23 and the separator 25 at the corner 22 are provided with the support 26, and the number of the support 26 is small and the arrangement position of the multiple supports 26 is relatively regular, so that the process difficulty of the battery cell 20 can be effectively reduced.

[0068] Referring to Figure 5 and Figure 6 In some embodiments, the support 26 is arranged on only one side of the positive electrode sheet 23 in the thickness direction, which can effectively improve the heat dissipation capacity of the positive electrode sheet 23. Of course, in other embodiments, the support 26 can also be arranged on both sides of the positive electrode sheet 23 in the thickness direction.

[0069] In some embodiments, in the radial direction of the battery cell 20, the size of the support 26 at the position closer to the outer surface of the battery cell 20 is smaller in the radial direction of the battery cell 20, because the curvature of the positive electrode sheet 23 at the position closer to the outer surface of the battery cell 20 is smaller, so that the stress concentration probability is smaller, the heat concentration is less, and the heat dissipation is easier after the battery cell 20 is expanded, so that the support 26 with smaller size can be arranged, and the overall design of the battery cell 20 is more reasonable.

[0070] Figure 2 For Figure 7 partial cross-sectional view of the battery cell 20 in the embodiment; Figure 6 For Figure 8 partial enlarged view of B in the embodiment; Figure 6 For Figures 6-8 structure diagram of the support 26 in the embodiment.

[0071] Referring to Figure 3 In some embodiments, the support 26 has a long strip shape structure, the support 26 has a length direction and a winding direction, the length direction of the support 26 is consistent with the height direction Z of the battery cell 20, and the winding direction of the support 26 is consistent with the winding direction R of the battery cell 20.

[0072] The size of the support 26 in the winding direction R of the battery cell 20 is usually much smaller than the size of the support 26 in the length direction. Moreover, the size of the support 26 in the radial direction of the battery cell 20 is smaller than the size of the support 26 in the winding direction R of the battery cell 20.

[0073] In some embodiments, the dimension of the positive electrode sheet 23 at the corner 22 in the winding direction R of the battery cell 20 is greater than the dimension of the support 26 in the winding direction R of the battery cell 20. Thus, by providing the support 26, a gap 201 can be formed at the corner 22 to improve the heat dissipation capacity at the corner 22. Since the support 26 has a sheet structure, the support 26 can be easily bonded with the separator 25 or the positive electrode sheet 23, thus reducing the process difficulty.

[0074] It can be understood that, in the present embodiment, the position of the support 26 can be referred to the position of the corner 22 in the winding direction R of the battery cell 20. Figure 4 or ​ Embodiments, which will not be described herein again.

[0075] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A battery, characterized by, The battery comprises a shell, a positive electrode sheet, a negative electrode sheet and a diaphragm between the positive electrode sheet and the negative electrode sheet accommodated in the shell, the positive electrode sheet, the diaphragm and the negative electrode sheet are wound to form an electric core, and a height direction of the battery is perpendicular to a winding direction of the electric core. The battery further comprises a support arranged at a corner of the electric core, the support is between the positive electrode sheet and the diaphragm or between the negative electrode sheet and the diaphragm, an extension direction of the support is consistent with the height direction of the battery, along the winding direction of the electric core, both sides of the support are provided with a gap, and the gap extends to a top surface or a bottom surface of the electric core in the height direction of the battery.

2. The battery of claim 1, wherein, In the height direction of the battery, both ends of the support extend to both ends of the electric core, and the gap penetrates the top surface and the bottom surface of the electric core in the height direction of the battery.

3. The battery according to claim 1 or 2, characterized in that, The electric core comprises a square main body and the corner on both sides of the main body in the width direction of the battery, curvatures of the positive electrode sheet, the diaphragm and the negative electrode sheet at the corner are greater than curvatures of the positive electrode sheet, the diaphragm and the negative electrode sheet at the main body, and the support is arranged at a middle position of the corner in the winding direction of the electric core.

4. The battery according to any one of claims 1 to 3, characterized in that, The positive electrode sheet and the diaphragm at the corner are both multilayered, and the support is arranged between the multilayered positive electrode sheet and the adjacent diaphragm.

5. The battery according to any one of claims 1 to 4, characterized in that, The support has a cylindrical structure, an axial direction of the support is consistent with the height direction of the battery, and an axial dimension of the support is consistent with the electric core in the height direction of the battery.

6. The battery of claim 5, wherein, Along the winding direction of the electric core, a plurality of supports are arranged between the positive electrode sheet and the diaphragm.

7. The battery according to any one of claims 1 to 4, wherein The support has a long strip sheet structure, and a size of the positive electrode sheet at the corner in the winding direction of the electric core is greater than a size of the support in the winding direction of the electric core.

8. The battery according to any one of claims 1 to 7, characterized in that, The support has the same material as the diaphragm.

9. The battery of claim 8, wherein, The support and the diaphragm are integrally formed.

10. The battery of claim 1, wherein, A size of the support in a stacking direction of the positive electrode sheet, the diaphragm and the negative electrode sheet is 1 μm-50 μm.

11. An energy storage device, characterized by, The energy storage device comprises a shell and the battery according to any one of claims 1-10, and the battery is arranged in the shell.

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