Battery cell, energy storage device and electric equipment

Abstract

According to the battery cell, the energy storage device and the electric equipment provided by the invention, in the working process of the energy storage device, when gas is generated by circular reaction in the battery cell, the gas in the battery cell can be smoothly discharged through the tab flattening layer, so that the thermal runaway risk of the energy storage device is reduced. The battery cell comprises a pole piece winding body and a tab rubbing layer, the tab rubbing layer is located on one side of the pole piece winding body in the height direction and connected to the pole piece winding body, the tab rubbing layer is provided with a first exhaust channel, and the first exhaust channel penetrates through the tab rubbing layer in the thickness direction of the tab rubbing layer. The distance between at least part of the first exhaust channel and the central axis of the battery cell is R / 2, and R is the radius of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a battery cell, an energy storage device and an electrical equipment. Background Art

[0002] In the prior art, after the electrode sheet of the battery cell is wound, the pole ear is often flattened to form a pole ear flattening layer, and the pole ear flattening layer has a high density. During the operation of the energy storage device, the gas generated by the internal circulation reaction of the battery cell cannot be discharged smoothly from the inside of the battery cell, causing the internal pressure of the battery cell to continue to increase, affecting the pressure of the explosion-proof valve to open the valve to release pressure, resulting in safety risks for the energy storage device. Utility Model Content

[0003] The present application provides a battery cell, an energy storage device, and an electrical device. During the operation of the energy storage device, the gas inside the battery cell can be smoothly discharged from the inside of the battery cell, thereby reducing the safety risk of the energy storage device.

[0004] In a first aspect, the present application provides a battery cell, comprising a pole piece winding body and a pole tab flattening layer, wherein the pole tab flattening layer is located on one side in the height direction of the pole piece winding body and is connected to the pole piece winding body, and the pole tab flattening layer is provided with a first exhaust channel, wherein at least a portion of the first exhaust channel penetrates the pole tab flattening layer along the height direction of the battery cell, wherein a distance between at least a portion of the first exhaust channel and a central axis of the battery cell is R / 2, wherein R is a radius of the battery cell.

[0005] Among them, the pole piece winding body includes a pole piece, the pole ear flattening layer includes a pole ear, the pole ear is located on one side in the width direction of the pole piece, the pole ear includes a connecting portion and a flattening portion, the connecting portion is connected to the pole piece, the flattening portion is connected to the surface of the connecting portion away from the pole piece, the flattening portion is provided with a plurality of first cutting notches, and the plurality of first cutting notches all penetrate the flattening portion along the thickness direction of the flattening portion, and along the winding direction of the pole piece, the plurality of first cutting notches are arranged in sequence at intervals, and the plurality of first cutting notches enclose to form the first exhaust channel.

[0006] Among them, the first exhaust channel has a first side surface and a second side surface, the minimum distance between the first side surface and the central axis of the battery cell is a first distance, and the first distance is less than or equal to R / 2, the second side surface is located on the side of the first side surface away from the central axis of the battery cell, and is spaced and opposite to the first side surface, the distance between the second side surface and the central axis of the battery cell is a second distance, and the second distance is greater than the first distance and greater than or equal to R / 2.

[0007] The first exhaust channel includes a plurality of first sub-exhaust channels, and the plurality of first sub-exhaust channels are spaced apart around the central axis of the battery cell, and the distance between at least a portion of each first sub-exhaust channel and the central axis of the battery cell is R / 2.

[0008] Each of the first exhaust sub-channels is in an arc ring shape, and each of the first exhaust sub-channels is arranged around the central axis of the battery cell.

[0009] Each of the first exhaust sub-channels is in a hole shape, and the distance between the central axis of each of the first exhaust sub-channels and the central axis of the battery cell is R / 2.

[0010] Among them, the tab flattening layer is also provided with a second exhaust channel, which is located on the side of the first exhaust channel away from the central axis of the battery cell and is spaced apart from the first exhaust channel. At least a portion of the second exhaust channel passes through the tab flattening layer along the height direction of the battery cell.

[0011] Among them, the tab flattening layer is also provided with a third exhaust channel, which is located on the side of the first exhaust channel facing the central axis of the battery cell and is spaced apart from the first exhaust channel. At least a portion of the third exhaust channel passes through the tab flattening layer along the height direction of the battery cell.

[0012] In the second aspect, the present application provides an energy storage device, comprising a shell, any one of the above-mentioned battery cells, a current collecting plate and a pole assembly, the shell being provided with a pole hole, the pole hole connecting the inner side and the outer side of the shell, the battery cell, the current collecting plate and the pole assembly being all arranged on the inner side of the shell, the current collecting plate being located on the side of the pole tab flattening layer away from the pole sheet winding body, and being electrically connected to the pole tab flattening layer, the current collecting plate being provided with an exhaust hole, the exhaust hole penetrating the current collecting plate along the thickness direction of the current collecting plate, and being connected to the first exhaust channel, and part of the pole assembly extending through the pole hole to the outer side of the shell.

[0013] In a third aspect, the present application provides an electrical device, comprising the energy storage device described above, wherein the energy storage device supplies power to the electrical device.

[0014] In the energy storage device described in the present application, the first exhaust channel is provided on the tab flattening layer. When the energy storage device is in operation, the internal circulation reaction of the battery cell generates gas, the gas inside the battery cell can be discharged from the first exhaust channel of the tab flattening layer, which can avoid the increase of internal pressure inside the battery cell and the explosion caused by the failure of the explosion-proof valve to open the valve to release pressure in time, thereby reducing the risk of thermal runaway of the energy storage device. In addition, during the operation of the energy storage device, when the internal circulation reaction of the battery cell generates gas, the maximum pressure position inside the battery cell is the position of R / 2 of the battery cell, and at least part of the first exhaust channel is at the position of R / 2 of the battery cell, so the gas at the maximum pressure position inside the battery cell can be discharged smoothly through the tab flattening layer in time, thereby reducing the risk of thermal runaway of the energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0016] Figure 1 is a schematic diagram of the structure of an energy storage system applied by the energy storage device provided in an embodiment of the present application;

[0017] Figure 2 is a schematic diagram of the structure of the energy storage device provided in an embodiment of the present application;

[0018] Figure 3 yes Figure 2 A schematic diagram of the exploded structure of the energy storage device shown;

[0019] Figure 4 yes Figure 3 A schematic diagram of the structure of a battery cell in the energy storage device shown;

[0020] Figure 5 yes Figure 4 The schematic diagram of the planar structure of the battery cell in the first embodiment is shown;

[0021] Figure 6 yes Figure 4 The schematic diagram of the planar structure of the battery cell in the second embodiment is shown;

[0022] Figure 7 yes Figure 6 A schematic diagram of the flattened structure of the battery cell shown;

[0023] Figure 8 yes Figure 4 The schematic diagram of the planar structure of the battery cell in the third embodiment is shown;

[0024] Fig. 9 yes Figure 4 The schematic diagram of the planar structure of the battery cell in the fourth embodiment;

[0025] Fig.10 yes Figure 4 The schematic diagram of the planar structure of the battery cell in the fifth embodiment is shown;

[0026] Fig.11 yes Figure 3 Schematic diagram of the partial exploded structure of the energy storage device shown.

[0027] The names corresponding to the reference numerals in the figure are: photovoltaic panel 2000, wind turbine 3000, power grid 4000, energy storage device 1000, housing 100, battery cell 200, current collecting plate 300, pole column assembly 400, main housing 110, end cover 120, first end cover 120a, second end cover 120b, first current collecting plate 300a, first pole column assembly 400a, pole piece winding body 210, pole ear flattening layer 220, first pole ear flattening layer 220a, second pole ear flattening layer 220b, center through hole 20 1, central axis O, central plane S, first exhaust channel 221, first side surface 2211, second side surface 2212, pole ear 222, pole piece 211, connecting portion 2221, flattened portion 2222, first cutting notch 2223, first sub-exhaust channel 223, first sub-side surface 2231, second sub-side surface 2232, second exhaust channel 224, third exhaust channel 225, second sub-exhaust channel 226, third sub-exhaust channel 227, explosion-proof hole 121, explosion-proof valve 500 and exhaust hole 301. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0029] Since the energy people need is highly temporal and spatial, in order to rationally utilize 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, the main way to generate green electricity is to develop green energy such as photovoltaics and wind power to replace fossil energy. At present, the generation of green electricity generally relies on photovoltaics, wind power, water potential, etc., while wind and solar energy generally have problems of strong intermittency and large volatility, which will cause instability of the power grid, insufficient electricity during peak hours, too much electricity during low hours, and unstable voltage will also cause damage to electricity. Therefore, it may cause "wind and light abandonment" problems due to insufficient electricity demand or insufficient grid acceptance capacity. To solve these problems, energy storage must be relied on. That is, electrical energy is converted into other forms of energy by physical or chemical means and stored, and energy is converted into electrical energy and released when needed. In simple terms, energy storage is similar to a large "power bank". When photovoltaic and wind energy are sufficient, electrical energy is stored and the stored electricity is released when needed.

[0030] Taking electrochemical energy storage as an example, this solution provides an energy storage device, which has a group of chemical batteries in it. The chemical elements in the chemical batteries are mainly used as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage media. Simply put, the electricity generated by wind and solar energy is stored in chemical batteries. When the use of external electricity reaches its peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0031] At present, energy storage (i.e. energy storage) has a wide range of application scenarios, including (wind and solar) power generation side energy storage, grid side energy storage, base station side energy storage and user side energy storage. The corresponding types of energy storage devices include:

[0032] (1) 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 electricity in time and space, enhance the ability to absorb renewable energy, and are of great significance in grid system backup, alleviating peak load power supply pressure, and peak and frequency regulation.

[0033] (2) Small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side mainly operate in the "peak shaving and valley filling" mode. Since there is a large price difference in electricity prices 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 to achieve the purpose of saving electricity bills.

[0034] Please refer to Figure 1 , Figure 1 It is a structural schematic diagram of an energy storage system applied to the energy storage device provided in an embodiment of the present application.

[0035] The energy storage device provided in the embodiment of the present application is applied to an energy storage system, which includes an electric energy conversion device (photovoltaic panel 2000), a wind energy conversion device (wind turbine 3000), a power grid 4000 and an energy storage device 1000. The energy storage device 1000 can be used as an energy storage cabinet and can be installed outdoors. Specifically, the photovoltaic panel 2000 can convert solar energy into electric energy during the period of low electricity prices. The energy storage device 1000 is used to store the electric energy and supply it to the power grid 4000 during peak power consumption, or to supply power when the power grid 4000 is powered off / out of power. The wind energy conversion device (wind turbine 3000) can convert wind energy into electric energy. The energy storage device 1000 is used to store the electric energy and supply it to the power grid 4000 during peak power consumption, or to supply power when the power grid 4000 is powered off / out of power. Among them, the transmission of electric energy can be transmitted using high-voltage cables.

[0036] The number of energy storage devices 1000 can be several, and several energy storage devices 1000 are connected in series or in parallel. Several energy storage devices 1000 are supported and electrically connected by isolation plates (not shown). In this embodiment, "several" refers to two or more. An energy storage box can also be provided outside the energy storage device 1000 to accommodate the energy storage device 1000.

[0037] It is understandable that the energy storage device 1000 may include but is not limited to a single cell, a battery module, a battery pack, a battery system, etc. The actual application form of the energy storage device provided in the embodiment of the present application may be but is not limited to the listed products, and may also be other application forms. The embodiment of the present application does not strictly limit the application form of the energy storage device 1000. The embodiment of the present application only takes the energy storage device 1000 as a multi-core battery as an example for explanation.

[0038] The embodiment of the present application is described by taking the energy storage device 1000 as a single battery as an example.

[0039] See also Figure 2 and Figure 3 , Figure 2 is a schematic diagram of the structure of the energy storage device 1000 provided in an embodiment of the present application, Figure 3 yes Figure 2 The schematic diagram of the exploded structure of the energy storage device is shown in FIG.

[0040] In this embodiment, the energy storage device 1000 is a cylindrical battery. The energy storage device 1000 includes a housing 100, a battery cell 200, a current collecting plate 300 and a pole assembly 400. The housing 100 is provided with a pole hole (not shown in the figure), and the pole hole connects the inner side and the outer side of the housing 100. Among them, there are two pole holes, and the two pole holes are arranged opposite to each other along the height direction of the housing 100 (Z-axis direction shown in the figure). Among them, the housing 100 includes a main housing 110 and an end cover 120. The main housing 110 has a receiving cavity (not shown in the figure) and an opening (not shown in the figure). The receiving cavity is located inside the housing 100 and contains electrolyte. There are two openings, and along the height direction of the housing 100 (Z-axis direction shown in the figure), the two openings are respectively located at opposite ends of the housing 100, and both are connected to the receiving cavity. There are two end covers 120, and along the height direction of the housing 100, the two end covers 120 are respectively installed at opposite ends of the housing 100, and the two openings are respectively closed. Each end cap 120 is provided with a pole hole. Exemplarily, the two end caps 120 are respectively a first end cap 120a and a second end cap 120b, the first end cap 120a is used as an end cap on the positive electrode side, and the second end cap 120b is used as an end cap on the negative electrode side. In some other embodiments, the energy storage device 1000 can also be a square battery or a battery of other shapes.

[0041] The battery cell 200, the current collecting plate 300 and the pole assembly 400 are all arranged on the inner side of the shell 100. Specifically, the battery cell 200 is accommodated in the accommodating cavity and immersed in the electrolyte. There are two current collecting plates 300. Along the height direction of the battery cell 200 (Z-axis direction shown in the figure), the two current collecting plates 300 are respectively located on opposite sides of the battery cell 200, and are both electrically connected to the battery cell 200. Among them, the two current collecting plates 300 are respectively the first current collecting plate 300a and the second current collecting plate (not shown in the figure). The first current collecting plate 300a is located between the first end cover 120a and the battery cell 200, and is electrically connected to the positive pole ear of the battery cell 200. The second current collecting plate is located between the second end cover 120b and the battery cell 200, and is electrically connected to the negative pole ear of the battery cell 200.

[0042] At least part of the pole assembly 400 extends to the outside of the housing 100 through the pole hole. There are two pole assemblies 400, the two pole assemblies 400 are the first pole assembly 400a and the second pole assembly (not shown). Among them, the first pole assembly 400a is used as the pole assembly on the positive side, and at least part of the first pole assembly 400a extends to the outside of the housing 100 through the pole hole of the first end cover 120a, and is electrically connected to the first current collecting disk 300a. The second pole assembly is used as the pole assembly on the negative side, and at least part of the second pole assembly extends to the outside of the housing 100 through the pole hole of the second end cover 120b, and is electrically connected to the second current collecting disk.

[0043] See also Figure 4 , Figure 4 yes Figure 3 A schematic structural diagram of a battery cell 200 in an energy storage device 1000 is shown.

[0044] The battery cell 200 includes a pole piece winding body 210 and a pole ear flattening layer 220. The pole piece winding body 210 includes two pole pieces (not shown) and a diaphragm (not shown), the two pole pieces are spaced and arranged opposite to each other, and the diaphragm is located between the two pole pieces. The two pole pieces and the diaphragm are wound along the length direction of the pole pieces to form the pole piece winding body 210. The two pole pieces are respectively a first pole piece and a second pole piece, the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

[0045] There are two tab flattening layers 220, which are located on opposite sides of the pole piece winding body 210 in the height direction (Z-axis direction in the figure), and are both connected to the pole piece winding body 210. The two tab flattening layers 220 are respectively the first tab flattening layer 220a and the second tab flattening layer 220b, the first tab flattening layer 220a is connected to the first pole piece, and the second tab flattening layer 220b is connected to the second pole piece.

[0046] The battery cell 200 is provided with a central through hole 201, which is located at the center of the battery cell 200 and penetrates the pole piece winding body 210 and the pole ear flattening layer 220 along the height direction of the battery cell 200. Exemplarily, the central through hole 201 is a circular hole. In addition, the battery cell 200 has a central axis O and a central plane S. The central axis O coincides with the axis of the central through hole 201. The central plane S is located between the central axis O and the peripheral surface of the battery cell 200, and is spaced from the central axis O and the peripheral surface of the battery cell 200. Among them, the distance between the central plane S and the central axis O is equal to the distance between the central plane S and the peripheral surface of the battery cell 200.

[0047] In this embodiment, the battery cell 200 is cylindrical, and the radius of the battery cell 200 is R. At this time, the center plane S of the battery cell 200 is at the R / 2 position of the battery cell 200, that is, the distance between the center plane S and the central axis O, and the distance between the center plane S and the peripheral surface of the battery cell 200 are both R / 2. It should be noted that the structures of the first tab flattening layer 220a and the second tab flattening layer 220b are the same. Next, the structure of the tab flattening layer 220 is described by taking the first tab flattening layer 220a as an example.

[0048] See also Figure 5 , Figure 5 yes Figure 4 The illustrated schematic diagram of the planar structure of the battery cell 200 in the first embodiment.

[0049] The tab flattening layer 220 is provided with a first exhaust channel 221, which is arranged around the central through hole 201 and the central axis O, and is spaced from the central through hole 201. Specifically, at least a portion of the first exhaust channel 221 passes through the tab flattening layer 220 along the height direction of the battery cell 200, and the pole piece winding body 210 is exposed. Exemplarily, the first exhaust channel 221 passes through the tab flattening layer 220 along the height direction of the battery cell 200. Among them, the first exhaust channel 221 is annular. Exemplarily, the first exhaust channel 221 is annular, and the axis of the first exhaust channel 221 coincides with the central axis O.

[0050] The first exhaust channel 221 has a first side surface 2211 and a second side surface 2212. The second side surface 2212 is located on a side of the first side surface 2211 away from the central axis O, and is spaced apart from and arranged opposite to the first side surface 2211. Exemplarily, the first side surface 2211 and the second side surface 2212 are parallel to each other, and the axes of the first side surface 2211 and the second side surface 2212 coincide with the central axis O. The minimum distance between the first side surface 2211 and the central axis O is a first distance D 1 The maximum distance between the second side surface 2212 and the central axis O is the second distance D 2 , D 1 Less than or equal to R / 2, D 2 Greater than D1 , and is greater than or equal to R / 2. That is, at least a portion of the first exhaust channel 221 is located at the position where the center plane S of the battery cell 200 is located.

[0051] In this embodiment, D 1 Less than R / 2, D 2 At this time, the center plane S of the battery cell 200 is located between the first side surface 2211 and the second side surface 2212, and is spaced apart from the first side surface 2211 and the second side surface 2212. That is, the first exhaust channel 221 is located at the position where the center plane S of the battery cell 200 is located, that is, the first exhaust channel 221 is located in the middle of the tab flattening layer 220.

[0052] In the energy storage device 1000 shown in the embodiment of the present application, a first exhaust channel 221 is provided on the tab flattening layer 220. When the energy storage device 1000 is in operation, the internal circulation reaction of the battery cell 200 generates gas, and the gas inside the battery cell 200 can be discharged from the first exhaust channel 221 of the tab flattening layer 220, which can avoid the problem of the internal pressure inside the battery cell 200 increasing, and the explosion caused by the failure of the explosion-proof valve to open the valve to release the pressure in time, thereby reducing the risk of thermal runaway of the energy storage device 1000. In addition, during the operation of the energy storage device 1000, when the internal circulation reaction of the battery cell 200 generates gas, the maximum pressure position inside the battery cell 200 is the position of R / 2 of the battery cell 200 (that is, the position of the central plane S of the battery cell 200), and at least part of the first exhaust channel 221 is at the position of R / 2 of the battery cell 200, and the gas at the maximum pressure position inside the battery cell 200 can be discharged smoothly through the tab flattening layer 220 in time, thereby reducing the risk of thermal runaway of the energy storage device 1000.

[0053] See also Figure 6 , Figure 6 yes Figure 4 The illustrated schematic diagram of the planar structure of the battery cell 200 in the second embodiment.

[0054] The battery cell 200 shown in this embodiment is different from the battery cell 200 shown in the first embodiment in that the first exhaust channel 221 includes a plurality of first sub-exhaust channels 223, and the plurality of first sub-exhaust channels 223 are arranged at intervals around the central through hole 201 and the central axis O. Exemplarily, the first exhaust channel 221 includes three first sub-exhaust channels 223. Specifically, at least a portion of each first sub-exhaust channel 223 passes through the tab flattening layer 220 along the height direction of the battery cell 200, and exposes the pole piece winding body 210. Exemplarily, each first sub-exhaust channel 223 is in an arc ring shape, each first sub-exhaust channel 223 is arranged around the central axis O of the battery cell 200, and the axis of each first sub-exhaust channel 223 coincides with the central axis O. It can be understood that each first sub-exhaust channel 223 is in an arc ring shape, which can increase the area of ​​the first exhaust channel 221 and help increase the exhaust speed of the first exhaust channel 221.

[0055] Each first sub-exhaust channel 223 includes a first sub-side surface 2231 and a second sub-side surface 2232. The second sub-side surface 2232 is located on a side of the first sub-side surface 2231 away from the central axis O, and is spaced apart from and arranged opposite to the first sub-side surface 2231. Exemplarily, the first sub-side surface 2231 and the second sub-side surface 2232 are parallel to each other, and the axes of the first sub-side surface 2231 and the second sub-side surface 2232 coincide with the central axis O. The minimum distance between the first sub-side surface 2231 and the central axis O is the third distance D 3 The maximum distance between the second side surface 2212 and the central axis O is the fourth distance D 4 , D 3 Less than or equal to R / 2, D 4 Greater than D 3 , and is greater than or equal to R / 2. That is, at least a portion of each first exhaust sub-channel 223 is located at the position where the center plane S of the battery cell 200 is located.

[0056] In this embodiment, D 3 Less than R / 2, D 4 At this time, the center plane S of the battery cell 200 is located between the first sub-side surface 2231 and the second sub-side surface 2232, and is spaced apart from the first sub-side surface 2231 and the second sub-side surface 2232. That is, the first sub-exhaust channel 223 is located at the position where the center plane S of the battery cell 200 is located, that is, the first sub-exhaust channel 223 is located in the middle of the tab flattening layer 220.

[0057] See also Figure 7 , Figure 7 yes Figure 6 A schematic diagram of the flattened structure of the battery cell 200 is shown.

[0058] The pole ear flattening layer 220 includes a pole ear 222, which is located on one side of the pole piece 211 in the width direction (Z-axis direction shown in the figure) and is connected to the pole piece 211. The pole ear 222 includes a connecting portion 2221 and a flattening portion 2222, and the connecting portion 2221 is located on one side of the pole piece 211 in the width direction and is connected to the pole piece 211. The flattening portion 2222 is connected to the surface of the connecting portion 2221 away from the pole piece 211. The flattening portion 2222 is provided with a plurality of first cutting notches 2223, and the plurality of first cutting notches 2223 all penetrate the flattening portion 2222 along the thickness direction of the flattening portion 2222 (Z-axis direction shown in the figure). Along the winding direction of the pole piece 211 (i.e., the length direction of the pole piece 211), the plurality of first cutting notches 2223 are arranged in sequence at intervals. Exemplarily, the first cutting notches 2223 can be formed by laser cutting. It should be noted that after the two pole pieces 211 and the diaphragm are wound along the length direction of the pole piece 211 to form the pole piece winding body 210, the pole ear 222 can be mechanically rolled by a flattening wheel to form a pole ear flattening layer 220. Among them, the first cutting notches 2223 of the flattening part 2222 enclose the first exhaust channel 221.

[0059] In the energy storage device 1000 shown in the embodiment of the present application, a plurality of first sub-exhaust channels 223 are provided on the tab flattening layer 220. When the energy storage device 1000 is in operation, when the internal circulation reaction of the battery cell 200 generates gas, the gas inside the battery cell 200 can be discharged from the plurality of first sub-exhaust channels 223 of the tab flattening layer 220, which can avoid the problem of the internal pressure inside the battery cell 200 increasing and the explosion caused by the failure to open the explosion-proof valve to release the pressure in time, thereby reducing the risk of thermal runaway of the energy storage device 1000. In addition, when the energy storage device 1000 is heated and produces gas, the maximum pressure position inside the battery cell 200 is the position of R / 2 of the battery cell 200, and the plurality of first sub-exhaust channels 223 are all at the position of R / 2 of the battery cell 200, so that the gas at the maximum pressure position inside the battery cell 200 can be discharged smoothly through the tab flattening layer 220 in time, thereby reducing the risk of thermal runaway of the energy storage device 1000.

[0060] See also Figure 8 , Figure 8 yes Figure 4 The illustrated schematic diagram of the planar structure of the battery cell 200 in the third embodiment.

[0061] The battery cell 200 shown in this embodiment is different from the battery cell 200 shown in the first embodiment in that the tab flattening layer 220 is further provided with a second exhaust channel 224 and a third exhaust channel 225, and at least part of the second exhaust channel 224 and at least part of the third exhaust channel 225 penetrate the tab flattening layer 220 along the height direction of the battery cell 200, and expose the pole piece winding body 210. Specifically, the second exhaust channel 224 is located on the side of the first exhaust channel 221 away from the central axis O, and is arranged around the first exhaust channel 221, and is spaced apart from the first exhaust channel 221. The third exhaust channel 225 is located on the side of the first exhaust channel 221 facing the central axis O, and is spaced apart from the first exhaust channel 221, and is connected to the central through hole 201. Exemplarily, the second exhaust channel 224 and the third exhaust channel 225 are both annular, and the second exhaust channel 224 and the third exhaust channel 225 are both parallel to the central plane S, and the axes of the second exhaust channel 224 and the third exhaust channel 225 coincide with the central axis O.

[0062] It should be noted that the second exhaust channel 224 and the third exhaust channel 225 can be formed in the same manner as the first exhaust channel 221. For example, the flattening portion 2222 is also provided with a plurality of second cutting notches and a plurality of third cutting notches, and the plurality of second cutting notches and the plurality of third cutting notches all penetrate the flattening portion 2222 along the thickness direction of the flattening portion 2222. Along the winding direction of the pole piece 211, the plurality of second cutting notches and the plurality of third cutting notches are respectively located on opposite sides of the plurality of first cutting notches 2223, and are arranged in sequence. Exemplarily, the second cutting notches and the third cutting notches can be formed by laser cutting. It should be noted that after the two pole pieces 211 and the diaphragm are wound along the length direction of the pole piece 211 to form the pole piece winding body 210, the pole ear 222 can be mechanically rolled by a flattening wheel to form a pole ear flattening layer 220. Among them, the plurality of second cutting notches enclose the second exhaust channel 224, and the plurality of third cutting notches enclose the third exhaust channel 225.

[0063] In some other embodiments, the tab flattening layer 220 may also be provided with only the first exhaust channel 221 and the second exhaust channel 224, or the tab flattening layer 220 may also be provided with only the first exhaust channel 221 and the third exhaust channel 225, and the present application does not impose any specific limitation on this.

[0064] In the present embodiment, a first exhaust channel 221, a second exhaust channel 224 and a third exhaust channel 225 are provided on the tab flattening layer 220. When the energy storage device 1000 is working and the internal circulation reaction of the battery cell 200 generates gas, the gas inside the battery cell 200 can be discharged from the first exhaust channel 221, the second exhaust channel 224 and the third exhaust channel 225 of the tab flattening layer 220, thereby avoiding the problem of increase in the internal pressure inside the battery cell 200 and explosion caused by failure to open the explosion-proof valve to release pressure in time, and effectively reducing the risk of thermal runaway of the energy storage device 1000.

[0065] See also Fig. 9 , Fig. 9 yes Figure 4 The illustrated schematic diagram of the planar structure of the battery cell 200 in the fourth embodiment.

[0066] The battery cell 200 shown in this embodiment is different from the battery cell 200 shown in the second embodiment in that the tab flattening layer 220 is further provided with a second exhaust channel 224 and a third exhaust channel 225, and at least a portion of the second exhaust channel 224 and at least a portion of the third exhaust channel 225 penetrate the tab flattening layer 220 along the height direction of the battery cell 200, and expose the pole piece winding body 210. Exemplarily, the entire second exhaust channel 224 and the entire third exhaust channel 225 penetrate the tab flattening layer 220 along the height direction of the battery cell 200.

[0067] Specifically, the second exhaust channel 224 is located on the side of the first exhaust channel 221 away from the central axis O, and is arranged around the first exhaust channel 221, and is spaced apart from the first exhaust channel 221. Among them, the second exhaust channel 224 includes a plurality of second sub-exhaust channels 226, and the plurality of second sub-exhaust channels 226 are spaced apart around the first exhaust channel 221. Exemplarily, the second exhaust channel 224 includes three second sub-exhaust channels 226. Specifically, at least a portion of each second sub-exhaust channel 226 passes through the tab flattening layer 220 along the height direction of the battery cell 200, and exposes the pole piece winding body 210. Exemplarily, each second sub-exhaust channel 226 is in an arc ring shape, each second sub-exhaust channel 226 is parallel to the center plane S, and the axis of each second sub-exhaust channel 226 coincides with the central axis O.

[0068] The third exhaust channel 225 is located on the side of the first exhaust channel 221 facing the central axis O, and is spaced apart from the first exhaust channel 221, and is connected to the central through hole 201. Among them, the third exhaust channel 225 includes a plurality of third sub-exhaust channels 227, and the plurality of third sub-exhaust channels 227 are spaced apart around the central through hole 201 and the central axis O. Exemplarily, the third exhaust channel 225 includes three third sub-exhaust channels 227. Specifically, at least a portion of each third sub-exhaust channel 227 passes through the tab flattening layer 220 along the height direction of the battery cell 200, and exposes the pole piece winding body 210, and is connected to the central through hole 201. Exemplarily, each third sub-exhaust channel 227 is in an arc ring shape, each third sub-exhaust channel 227 is parallel to the central plane S, and the axis of each third sub-exhaust channel 227 coincides with the central axis O.

[0069] In the present embodiment, a plurality of first sub-exhaust channels 223, a plurality of second sub-exhaust channels 226 and a plurality of third sub-exhaust channels 227 are provided on the tab flattening layer 220. When the energy storage device 1000 is in operation and the internal circulation reaction of the battery cell 200 generates gas, the gas inside the battery cell 200 can be discharged from the plurality of first sub-exhaust channels 223, the plurality of second sub-exhaust channels 226 and the plurality of third sub-exhaust channels 227 of the tab flattening layer 220. This can avoid the problem of increase in internal pressure inside the battery cell 200 and explosion caused by failure to open the explosion-proof valve to release pressure in time, and can effectively reduce the risk of thermal runaway of the energy storage device 1000.

[0070] See also Fig.10 , Fig.10 yes Figure 4 The schematic diagram of the planar structure of the battery cell 200 in the fifth embodiment is shown.

[0071] The battery cell 200 shown in this embodiment is different from the battery cell 200 shown in the second embodiment described above in that each first sub-exhaust channel 223 is in the shape of a hole. A plurality of first sub-exhaust channels 223 are randomly arranged in the circumferential direction of the center plane S. The distance between the center axis of each first sub-exhaust channel 223 and the center axis of the battery cell 200 is R / 2. That is, the center axis of each first sub-exhaust channel 223 is located on the center plane S of the battery cell 200. It should be understood that the shape of the first sub-exhaust channel 223 is not limited to Fig.10 The circle shown may also be a triangle, a square or other special shapes.

[0072] In addition, the tab flattening layer 220 is also provided with a third exhaust channel 225, at least part of which penetrates the tab flattening layer 220 along the height direction of the battery cell 200 and exposes the pole piece winding body 210. Specifically, the third exhaust channel 225 is located on the side of the first exhaust channel 221 facing the central axis O, and is spaced apart from the first exhaust channel 221, and is connected to the central through hole 201. Exemplarily, the third exhaust channel 225 is in a circular shape, the third exhaust channel 225 is parallel to the central plane S, and the axis of the third exhaust channel 225 coincides with the central axis O.

[0073] In the energy storage device 1000 shown in the embodiment of the present application, a plurality of first sub-exhaust channels 223 and a third exhaust channel 225 are provided on the tab flattening layer 220. When the energy storage device 1000 is in operation and the internal circulation reaction of the battery cell 200 generates gas, the gas inside the battery cell 200 can be discharged from the plurality of first sub-exhaust channels 223 and the third exhaust channel 225 of the tab flattening layer 220, thereby avoiding the problem of increase in the internal pressure inside the battery cell 200 and explosion caused by failure to open the explosion-proof valve to release pressure in time, thereby reducing the risk of thermal runaway of the energy storage device 1000.

[0074] See also Figure 4 and Fig.11 , Fig.11 yes Figure 3 A schematic diagram of a partial exploded structure of the energy storage device 1000 is shown.

[0075] The end cover 120 is provided with an explosion-proof hole 121, which penetrates the end cover 121 along the thickness direction of the end cover 120 (Z-axis direction in the figure). The energy storage device 1000 also includes an explosion-proof valve 500, which is installed on the end cover 120 and covers the explosion-proof hole 121. The collector plate 300 is located on the side of the end cover 120 facing the battery cell 200, and is electrically connected to the tab flattening layer 220. The collector plate 300 is provided with an exhaust hole 301, which penetrates the collector plate 300 along the thickness direction of the collector plate 300 (Z-axis direction in the figure), and is connected to the first exhaust channel 221. There are multiple exhaust holes 301, and the multiple exhaust holes 301 are arranged at intervals from each other.

[0076] In the embodiment of the present application, a first exhaust channel 221 is provided on the tab flattening layer 220. When the energy storage device 1000 generates gas due to heat, the gas inside the battery cell 200 can be discharged from the first exhaust channel 221 of the tab flattening layer 220, and then impact the explosion-proof valve 500 through the exhaust hole 301 of the collecting plate 300. The explosion-proof valve 500 can open the valve to release pressure to discharge the gas to the outside of the energy storage device 1000, thereby avoiding the problem of explosion caused by the increase of the internal pressure inside the battery cell 200 and the failure of the explosion-proof valve 500 to open the valve to release pressure in time, thereby reducing the risk of thermal runaway of the energy storage device 1000.

[0077] The embodiment of the present application also provides an electric device, which includes the energy storage device 1000, and the energy storage device 1000 supplies power to the electric device. The electric device may be a new energy vehicle, a power storage station, a server, or other equipment that requires electricity.

[0078] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application; in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A battery cell, characterized in that: It includes a pole piece winding body and a pole lug flattening layer, wherein the pole lug flattening layer is located on one side of the pole piece winding body in the height direction and is connected to the pole piece winding body, and the pole lug flattening layer is provided with a first exhaust channel, wherein at least a portion of the first exhaust channel penetrates the pole lug flattening layer along the height direction of the battery cell, wherein the distance between at least a portion of the first exhaust channel and the central axis of the battery cell is R / 2, wherein R is the radius of the battery cell.

2. The battery cell according to claim 1, characterized in that: The pole piece winding body includes a pole piece, and the pole ear flattening layer includes a pole ear, and the pole ear is located on one side of the pole piece in the width direction, and the pole ear includes a connecting portion and a flattening portion, the connecting portion is connected to the pole piece, and the flattening portion is connected to the surface of the connecting portion away from the pole piece, and the flattening portion is provided with a plurality of first cutting notches, and the plurality of first cutting notches all penetrate the flattening portion along the thickness direction of the flattening portion, and along the winding direction of the pole piece, the plurality of first cutting notches are arranged in sequence at intervals, and the plurality of first cutting notches enclose to form the first exhaust channel.

3. The battery cell according to claim 1 or 2, characterized in that: The first exhaust channel has a first side surface and a second side surface, the minimum distance between the first side surface and the central axis (O) of the battery cell is a first distance, the first distance is less than or equal to R / 2, the second side surface is located on the side of the first side surface away from the central axis of the battery cell, and is spaced apart and opposite to the first side surface, the distance between the second side surface and the central axis of the battery cell is a second distance, the second distance is greater than the first distance, and greater than or equal to R / 2.

4. The battery cell according to claim 1 or 2, characterized in that: The first exhaust channel includes a plurality of first sub-exhaust channels, and the plurality of first sub-exhaust channels are spaced around the central axis of the battery cell, and the distance between at least a portion of each first sub-exhaust channel and the central axis of the battery cell is R / 2.

5. The battery cell according to claim 4, characterized in that: Each of the first exhaust sub-channels is in an arc ring shape, and each of the first exhaust sub-channels is arranged around the central axis of the battery core.

6. The battery cell according to claim 4, characterized in that: Each of the first exhaust sub-channels is in a hole shape, and a distance between a central axis of each of the first exhaust sub-channels and a central axis of the battery cell is R / 2.

7. The battery cell according to claim 1 or 2, characterized in that: The tab flattening layer is also provided with a second exhaust channel, which is located on the side of the first exhaust channel away from the central axis of the battery cell and is spaced apart from the first exhaust channel. At least a portion of the second exhaust channel passes through the tab flattening layer along the height direction of the battery cell.

8. The battery cell according to claim 1 or 2, characterized in that: The tab flattening layer is also provided with a third exhaust channel, which is located on the side of the first exhaust channel facing the central axis of the battery cell and is spaced apart from the first exhaust channel. At least a portion of the third exhaust channel passes through the tab flattening layer along the height direction of the battery cell.

9. An energy storage device, characterized in that: It comprises a shell, a battery cell, a current collecting disk and a pole assembly as described in any one of claims 1 to 8, the shell is provided with a pole hole, the pole hole connects the inner side and the outer side of the shell, the battery cell, the current collecting disk and the pole assembly are all arranged on the inner side of the shell, the current collecting disk is located on the side of the pole tab flattening layer away from the pole piece winding body, and is electrically connected to the pole tab flattening layer, the current collecting disk is provided with an exhaust hole, the exhaust hole penetrates the current collecting disk along the thickness direction of the current collecting disk, and is connected to the first exhaust channel, and at least part of the pole assembly extends to the outside of the shell through the pole hole.

10. An electrical device, characterized in that: It includes the energy storage device as described in claim 9, and the energy storage device supplies power to the electrical equipment.

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