Cylindrical battery and electric device

Abstract

The embodiment of the present application provides a cylindrical battery and an electric device, the cylindrical battery comprising: a shell, the shell comprising a first end plate at one end of the axial direction, the first end plate being provided with a pressure relief valve; an electric core, the electric core being arranged in the shell, a middle part of the electric core being formed with a winding core hole, the winding core hole extending along the axial direction of the shell, the electric core comprising a body part and a tab part, at least one tab part being led out from the body part towards one end of the first end plate; a current collector, the current collector being arranged between the first end plate and the electric core, the current collector being electrically connected with the tab part of the electric core and the electrode of the cylindrical battery respectively, the current collector being provided with a first through hole; the projection of the winding core hole and the current collector on the plane of the first end plate at least partially coincides with the pressure relief valve; wherein the sum of the areas of the first through hole S1, the end surface area of the electric core S0 and the cross-sectional area of the winding core hole S2 satisfy: 0.06*10 ‑3 ≤ (S1*S2) / (S0*S0) ≤ 11.25*10 ‑3 . The cylindrical battery can timely release pressure, and can ensure the current overcurrent area of the current collector.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a cylindrical battery and electrical equipment. Background Technology

[0002] Cylindrical batteries have a higher energy density and greater utilization of internal space compared to prismatic batteries, and are therefore widely used in the new energy field.

[0003] In related technologies, because the wound battery cells occupy most of the effective volume inside the cylindrical casing, gas generated inside the battery tends to accumulate at the cell ends. Furthermore, the current collector, located between the cell end face and the casing end wall, can obstruct the pressure relief valve. In the event of a short circuit and thermal runaway, delayed pressure relief may occur. If the pressure relief valve opens, an open flame may appear, potentially causing rapid thermal runaway in adjacent batteries and compromising the overall safety of the battery pack. Summary of the Invention

[0004] This application provides a cylindrical battery and an electrical device to improve the overall venting efficiency of the cylindrical battery, so that the cylindrical battery can be depressurized in a timely manner during thermal runaway.

[0005] In a first aspect, embodiments of this application provide a cylindrical battery, comprising: a housing, the housing including a first end plate located at one end along its own axial direction, the first end plate being provided with a pressure relief valve; a battery cell disposed within the housing, the battery cell having a winding hole formed in its middle portion, the winding hole extending along the axial direction of the housing, the battery cell including a body portion and a tab portion, at least one of the tab portions extending from the body portion toward the first end plate; a current collector disposed between the first end plate and the battery cell, the current collector being electrically connected to the tab portion of the battery cell and the electrode of the cylindrical battery respectively, the current collector having a first through hole, the first through hole penetrating the current collector in a direction parallel to the axial direction of the housing; the projections of the winding hole and the current collector on the plane of the first end plate at least partially coincide with the pressure relief valve; wherein, the sum of the areas of the first through holes S1, the end face area of ​​the battery cell S0, and the cross-sectional area of ​​the winding hole S2 satisfy: 0.06 × 10⁻⁶. -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3 .

[0006] Secondly, embodiments of this application provide an electrical device, including the cylindrical battery described above.

[0007] This application provides a cylindrical battery and electrical device. By providing a first through hole in the current collector located between the battery cell and the first end plate equipped with a pressure relief valve, the flow area of ​​the gas passage from the core hole to the pressure relief valve is increased, and the gas diffusion path is shortened. This improves the overall venting efficiency of the cylindrical battery, achieving timely pressure relief. Furthermore, by optimizing the size of the battery cell and the size of the first through hole, the cylindrical battery meets the requirement of 0.06 × 10⁻⁶ mm. -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3 To prevent the current collector from blocking the end face of the cell facing the pressure relief valve, the pressure relief path of the cell end face is increased, ensuring that the high-temperature and high-pressure gas in the cylindrical battery can quickly reach the pressure relief valve area in the event of thermal runaway, so that the pressure relief valve can open in time to release pressure. At the same time, to avoid reducing the current flow area of ​​the current collector after setting the first through hole on the current collector, which would increase the resistance of the current collector and cause the heat generated by the current collector to be concentrated during charging and discharging, resulting in an excessively fast battery temperature rise rate, affecting the battery charging and discharging performance, or even causing the current collector to melt. This also avoids the problem of the cell charging and discharging speed being too slow and the current between the inside and outside of the cell being cut off due to this problem. Attached Figure Description

[0008] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0009] Figure 1 This is a schematic diagram of the structure of a cylindrical battery provided in some embodiments of this application.

[0010] Figure 2 This is a schematic diagram of the current collector provided in an embodiment of this application.

[0011] Figure 3 This is a schematic diagram from another perspective of the current collector provided in the embodiments of this application.

[0012] Figure 4 This is a schematic cross-sectional view of a cylindrical battery along section AA, provided in some embodiments of this application.

[0013] Figure 5 This is a schematic cross-sectional view of a cylindrical battery along section BB, provided in some embodiments of this application.

[0014] Figure 6 for Figure 5 The circled portion C is a magnified view of a part of the image.

[0015] Figure 7 This is a schematic diagram of the structure of the insulating connector and current collector provided in the embodiments of this application.

[0016] Figure 8 This is a schematic diagram from another perspective of the insulating connector and current collector provided in the embodiments of the application.

[0017] Figure 9 This is a schematic diagram of the structure of the insulating connector provided in the embodiment of this application.

[0018] Figure 10 This is a schematic diagram of the current collector and battery cell provided in the embodiments of this application.

[0019] Figure 11 This is a schematic diagram of the battery cell structure provided in an embodiment of this application.

[0020] Figure 12 This is a schematic diagram of the structure of a cylindrical battery provided in some of the second embodiments of this application.

[0021] Figure 13 This is a partial schematic diagram of a cylindrical battery according to an embodiment of this application.

[0022] Explanation of reference numerals in the attached drawings: 10-Cylindrical battery; 100-Casing; 101-Casing body; 110-First end plate; 111-Pressure relief valve; 1111-Weak section; 112-First recess; 1121-Bottom wall; 120-Second end plate; 200-Cell; 201-Exposed area; 202-Exposed area; 210-Core hole; 220-Taper portion; 220a-Positive tab; 220b-Negative tab; 221-First tab portion; 230 - Body; 300- Current collector; 300a- Positive current collector; 300b- Negative current collector; 301- First through hole; 302- First welding area; 303- Second welding area; 304- Non-welding area; 400- Electrode; 410- Terminal post; 500- Insulating component; 510- First insulating ring; 520- Second insulating ring; 600- Insulating connector; 610- Second through hole; 601- First slot; 602- Second slot.

[0023] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0025] Cylindrical batteries have a higher energy density and greater utilization of internal space compared to prismatic batteries, and are therefore widely used in the new energy field.

[0026] In related technologies, cylindrical batteries offer greater space utilization. The wound cells occupy a large portion of the effective volume within the cylindrical casing, resulting in less space for gas to accumulate at the cell ends. Simultaneously, to ensure the battery's overcurrent performance and improve its charge / discharge rate, improvements in overcurrent control are necessary, particularly in the current collector, which acts as the intermediary between the cells and the battery electrodes. Therefore, the current collector needs a larger overcurrent area. However, the current collector is located between the cell end face and the end wall of the casing where the pressure relief valve is located. In the event of a short circuit and thermal runaway, an excessively large current collector can obstruct the pressure relief valve, blocking the pressure relief path for high-temperature, high-pressure gas inside the battery, potentially leading to delayed pressure relief. Furthermore, slow pressure relief can cause temperature buildup inside the battery, increasing the likelihood of flames erupting after the pressure relief valve opens. The high-temperature gas can also cause adjacent cells to heat up rapidly, potentially triggering a chain reaction of thermal runaway and compromising the overall safety of the battery pack.

[0027] For example, research has found that in cylindrical batteries, the electrodes are too tightly packed after the cells are wound, causing the cells to expand circumferentially after charging and discharging. The gap between the cells and the casing is small, and the gas transmission channels of the battery are concentrated in the axial direction of the cells to exhaust gas, causing gas to accumulate on the end face. In addition, the end face size is limited by the size of the wound core, and the pressure relief valve is blocked by the current collector, resulting in untimely pressure relief and excessive burst pressure, causing open flames to appear on the outside of the cylindrical battery.

[0028] This application provides a cylindrical battery and an electrical device to improve the overall venting efficiency of the cylindrical battery, so that the cylindrical battery can be depressurized in a timely manner during thermal runaway.

[0029] The cylindrical battery and electrical device provided in this application embodiment improve the overall venting efficiency of the cylindrical battery by providing a first through hole in the current collector located between the battery cell and the first end plate equipped with a pressure relief valve. This increases the flow area of ​​the gas passage from the core hole to the pressure relief valve and shortens the gas diffusion path, thereby achieving the technical effect of timely pressure relief of the cylindrical battery. Furthermore, by optimizing the size of the battery cell and the size of the first through hole, the cylindrical battery meets the requirement of 0.06 × 10⁻⁶ mm. -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3To prevent the current collector from blocking the end face of the cell facing the pressure relief valve, the pressure relief path of the cell end face is increased, ensuring that the high-temperature and high-pressure gas in the cylindrical battery can quickly reach the pressure relief valve area in the event of thermal runaway, so that the pressure relief valve can open in time to release pressure. At the same time, to avoid reducing the current flow area of ​​the current collector after setting the first through hole on the current collector, which would increase the resistance of the current collector and cause the heat generated by the current collector to be concentrated during charging and discharging, resulting in an excessively fast battery temperature rise rate, affecting the battery charging and discharging performance, or even causing the current collector to melt. This also avoids the problem of the cell charging and discharging speed being too slow and the current between the inside and outside of the cell being cut off due to this problem.

[0030] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 12 and Figure 13 As shown, the cylindrical battery 10 (hereinafter referred to as the battery) provided in this application embodiment may include a casing 100, a cell 200 and a current collector 300.

[0031] The housing 100 includes a first end plate 110 located at one end of its own axial direction, and the first end plate 110 is provided with a pressure relief valve 111.

[0032] Understandably, the housing 100 is cylindrical. The housing 100 is a component used to provide a space to house the battery cell 200 and other components and to isolate them from the outside world.

[0033] For example, the material of the housing 100 includes, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0034] For example, the housing 100 may also include a housing body 101, a first end plate 110 and a second end plate 120; the housing body 101 is cylindrical and the second end plate 120 is located at the end of the housing body 101 opposite to the first end plate 110 in the axial direction.

[0035] The battery cell 200 is disposed inside the housing 100. A winding hole 210 is formed in the middle of the battery cell 200. The winding hole 210 extends along the axial direction of the housing 100. The battery cell 200 includes a body portion 230 and a tab portion 220. At least one tab portion 220 is led out from one end of the body portion 230 toward the first end plate 110.

[0036] It should be noted that the main body 230 is the component in the cylindrical battery 10 where electrochemical reactions occur, and the main body 230 is the smallest unit in the cylindrical battery 10 capable of performing electrochemical reactions such as charging or discharging. The tab 220 is used to transmit current between the main body 230 and the outside world.

[0037] For example, the body portion 230 is formed by winding a positive electrode, a negative electrode, and a separator disposed between them. Lithium-ion battery cells mainly rely on the insertion and extraction movement of lithium ions between the positive and negative electrode plates to operate.

[0038] For example, a positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive active materials for batteries. These positive active materials can be used alone or in combination. The lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2, which can also be abbreviated as NCM333, and LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0039] The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene and carbon nanofibers.

[0040] For example, during battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through an external circuit to maintain charge balance; during discharge, the active ions (such as Li) previously embedded in the negative electrode can be released, while electrons from the negative electrode are transferred to the negative electrode through an external circuit to maintain charge balance; thus achieving energy storage and release.

[0041] For example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector is a conductive metal foil, which may be made of stainless steel, copper, aluminum, nickel, carbon electrode, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The negative electrode active layer includes a negative electrode active material, a conductive agent, a binder, etc.

[0042] For example, the negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-nitrogen composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0043] A current collector 300 is disposed between the first end plate 110 and the cell 200; the current collector 300 is electrically connected to the tab portion 220 of the cell 200, and the current collector 300 is also electrically connected to the electrode 400 of the cylindrical battery 10. It should be noted that the electrode 400 at this location may include both the positive and negative terminals of the cylindrical battery 10; or, the electrode 400 at this location may include only one of the positive and negative terminals of the cylindrical battery 10.

[0044] For example, the current collector 300 may include two parts that are insulated from each other. In this scenario, one part of the current collector 300 may be electrically connected to the positive terminal of the cylindrical battery 10, and the other part of the current collector 300 may be electrically connected to the negative terminal of the cylindrical battery 10. That is, in this scenario, the current collector 300 is also electrically connected to the electrode 400 of the cylindrical battery 10, where the electrode 400 includes both the positive and negative terminals of the cylindrical battery 10.

[0045] Alternatively, the current collector 300 may be electrically connected to only one of the positive and negative terminals of the cylindrical battery. That is, in this scenario, the current collector 300 may also be electrically connected to the electrode 400 of the cylindrical battery 10, where the electrode 400 includes only one of the positive and negative terminals of the cylindrical battery 10.

[0046] The current collector 300 is provided with a first through hole 301. For example, there may be multiple first through holes 301. The shapes of the multiple first through holes 301 may be the same or different. The areas of the multiple first through holes 301 may be the same or different.

[0047] For example, in this embodiment, most of the first through holes 301 are circular, and a small portion of the first through holes 301 are circular.

[0048] For example, in some possible embodiments, the first through hole 301 may be elliptical, rectangular, trapezoidal or other irregular shapes.

[0049] It should be noted that the current collector 300 of the cylindrical battery 10 may include a positive current collector 300a and a negative current collector 300b.

[0050] In this embodiment: the current collector 300 being disposed between the first end plate 110 and the cell 200 means that both the positive current collector 300a and the negative current collector 300b are disposed between the first end plate 110 and the cell 200, that is, the positive current collector 300a and the negative current collector 300b are located at the same end of the axial direction of the cylindrical battery 10; the current collector 300 being provided with a first through hole 301 means that the first through hole 301 can be provided only on the positive current collector 300a, or only on the negative current collector 300b, or both the positive current collector 300a and the negative current collector 300b can be provided with the first through hole 301.

[0051] In some possible embodiments: the current collector 300 being disposed between the first end plate 110 and the cell 200 means that one of the positive current collector 300a and the negative current collector 300b is disposed between the first end plate 110 and the cell 200, that is, one of the positive current collector 300a and the negative current collector 300b is located at one end of the cylindrical battery 10 along the axial direction, and the other of the positive current collector 300a and the negative current collector 300b is located at the other end of the cylindrical battery 10 along the axial direction. It can be understood that, at this time, the current collector 300 having a first through hole 301 means that the current collector 300 disposed between the first end plate 110 and the cell 200 has a first through hole 301, and the first through hole 301 penetrates the current collector 300 in an axial direction parallel to the housing 100.

[0052] The projections of the core hole 210 and the current collector 300 onto the plane of the first end plate 110 are at least partially located inside the pressure relief valve 111. In other words, the projections of the core hole 210 and the current collector 300 onto the first end plate 110 coincide at least partially with the pressure relief valve 111. It can be understood that the projection plane at this location is approximately perpendicular to the axial direction of the cylindrical battery 10. The sum of the areas S1 of the first through holes 301, the end face area S0 of the cell 200, and the cross-sectional area S2 of the core hole 210 satisfy: 0.06 × 10⁻⁶. -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3 .

[0053] For example, (S1×S2) / (S0×S0) can be 0.06×10 -3 0.11×10 -3 0.12×10 -3 0.44×10 -3 0.89×10 -3 1.41×10 -3 2.25×10 -3 2.69×10 -3 3.70×10 -3 5.27×10 -3 6.81×10 -3 9.49×10 -3 9.57×10 -3 Or 11.25×10 -3 Of course, the embodiments in this application do not impose limitations on this, and reasonable choices can be made within the above-mentioned range.

[0054] The cylindrical battery 10 provided in this application embodiment improves the overall venting efficiency of the cylindrical battery 10 by providing a first through hole 301 on the current collector 300 located between the cell 200 and the first end plate 110 equipped with a pressure relief valve 111. This increases the flow area of ​​the gas passage from the winding hole 210 to the pressure relief valve 111 and shortens the gas diffusion path, thereby achieving the technical effect of timely pressure relief of the cylindrical battery 10. Furthermore, by optimizing the size of the cell 200 and the size of the first through hole 301, the cylindrical battery 10 meets the requirement of 0.06 × 10⁻⁶ mm. -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3To prevent the current collector 300 from blocking the end face of the cell 200 facing the pressure relief valve 111, the pressure relief path of the cell 200 end face is increased, ensuring that the high-temperature and high-pressure gas in the cylindrical battery 10 can quickly reach the pressure relief valve 111 area in the event of thermal runaway, so that the pressure relief valve 111 can open in time to release pressure. At the same time, to avoid reducing the current flow area of ​​the current collector 300 after setting the first through hole 301 on the current collector 300, which would increase the resistance of the current collector 300 and cause the current collector 300 to concentrate heat during charging and discharging, resulting in an excessively fast battery temperature rise rate, affecting the battery charging and discharging performance, or even causing the current collector 300 to melt. This also avoids the problem of the cell 200 charging and discharging speed being too slow, and prevents the current between the inside and outside of the cell 200 from being cut off due to this problem.

[0055] It should be noted that when (S1×S2) / (S0×S0) is relatively small (e.g., less than 0.06×10), -3 When (S1×S2) / (S0×S0) is too small, the current collector 300 severely obstructs the pressure relief channel of the cylindrical battery 10, which is not conducive to the pressure relief of the cylindrical battery 10.

[0056] When (S1×S2) / (S0×S0) is too large (e.g., greater than 11.25×10), -3 When (S1×S2) / (S0×S0) is too large, it can easily cause serious heat generation in the battery. Understandably, when (S1×S2) / (S0×S0) is too large, it can easily cause the resistance of the current collector 300 to increase. The increased resistance of the current collector 300 leads to concentrated heat generation, and the temperature rise further increases the resistance, creating a vicious cycle that can lead to the risk of the current collector 300 melting.

[0057] When the diameter of the first through hole 301 is enlarged (directly affecting the total area of ​​the first through hole 301), the electron conduction path changes from a short radial path to a long-stroke bypass, and the contact resistance between the corresponding electrode 400 of the cylindrical battery 10 and the corresponding current collector 300 increases.

[0058] In some embodiments, the end face area S0 of the battery cell 200 ranges from 314 mm. 2 -3017.54 mm 2 For example, the end face area S0 of cell 200 can be 314 mm². 2 500 mm 2 1000 mm 2 1500 mm 2 2000 mm 2 2500mm 2 3000 mm 2 Or 3017.54 mm 2This is to ensure that the cell 200 has sufficient volume, thereby maintaining sufficient capacity.

[0059] The sum of the areas S1 of the first through hole 301 is within the range of 3.14 mm. 2 -603.51mm 2 For example, the sum of the areas S1 of the first through holes 301 can be 3.14 mm. 2 50 mm 2 100 mm 2 200 mm 2 300 mm 2 400 mm 2 500 mm 2 600 mm 2 Or 603.51 mm 2 To balance flow capacity and gas throughput efficiency.

[0060] The cross-sectional area S2 of the core hole 210 ranges from 3.14 mm. 2 -78.5mm 2 The cross-sectional area S2 of the core hole 210 can be 3.14 mm. 2 10 mm 2 31.4 mm 2 50 mm 2 or 78.5mm 2 .

[0061] The value range of S1 / S0 is 0.01-0.2. For example, S1 / S0 can be 0.01, 0.03, 0.05, 0.08, 0.1, 0.12, 0.15, 0.17, or 0.2. This serves two purposes: firstly, it prevents the current-carrying area of ​​the current collector 300 from decreasing due to an excessively large area, leading to increased resistance and severe overheating; secondly, it prevents the exhaust from being obstructed and pressure relief from being delayed due to an excessively small area of ​​the first through-hole 301.

[0062] The value range of S2 / S0 is 0.004-0.063. For example, S2 / S0 can be 0.004, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, or 0.063. This avoids the effective volume of the cell 200 being reduced due to an excessively large cross-sectional area of ​​the winding hole 210, thus leading to a decrease in energy density. It also avoids the situation where the gas migration efficiency inside the battery is reduced due to an excessively small cross-sectional area of ​​the winding hole 210, resulting in increased local gas pressure and untimely pressure relief.

[0063] Reference Figure 1 and Figure 4As shown, in some embodiments, the projection of the winding core hole 210 on the first end plate 110 is located inside the pressure relief valve 111. In this way, the flow path of the gas flowing from the winding core hole 210 to the pressure relief valve 111 can be further reduced, so as to facilitate further and timely pressure relief of the cylindrical battery 10.

[0064] For example, the first end plate 110 includes a first recess 112, which can be annular, fan-shaped, arc-shaped, elliptical, or any other arbitrary shape. The area on the first end plate 110 surrounded by the first recess 112 is the main body of the pressure relief valve 111, which is the pressure relief area of ​​the pressure relief valve 111. This part opens to relieve pressure when the internal pressure of the cylindrical battery 10 abnormally increases. The projection of the core hole 210 on the first end plate 110 is inside the pressure relief valve 111, and can be regarded as the portion of the projection of the core hole 210 on the first end plate 110 located within the annular inner circle of the first recess 112.

[0065] Reference Figure 1 , Figure 5 and Figure 6 As shown, in some embodiments, the pressure relief valve 111 includes a weak portion 1111, the projection of which does not coincide with the projection of the core hole 210 on the first end plate 110. In this embodiment, by ensuring that the projections of the weak portion 1111 and the core hole 210 on the first end plate 110 do not coincide, the purpose of preventing the weak portion 1111 and the core hole 210 from being directly opposite each other in the axial direction of the cylindrical battery 10 is achieved. Thus, the problem of abnormal opening of the pressure relief valve 111 can be avoided.

[0066] It should be noted that non-overlap means that the projection of the weak part 1111 of the pressure relief valve 111 and the projection of the core hole 210 are completely misaligned in the vertical direction.

[0067] It should be noted that when the internal pressure of the cylindrical battery 10 rises abnormally, the weak part 1111 can be torn, so that the pressure relief area of ​​the pressure relief valve 111 can be opened to relieve the pressure of the cylindrical battery 10.

[0068] When the weak part 1111 of the pressure relief valve 111 does not coincide with the projection of the core hole 210, the gas must bypass the edge of the weak part 1111 when it is axially transmitted through the core hole 210 to the pressure relief area of ​​the pressure relief valve 111. This design makes the gas distribution in the pressure relief area of ​​the pressure relief valve 111 more uniform, avoids local pressure concentration, and thus avoids abnormal opening of the pressure relief valve 111.

[0069] Reference Figure 1 , Figure 5 and Figure 6As shown, in some embodiments, when the pressure relief valve 111 includes a weak portion 1111, and the projection of the weak portion 1111 onto the first end plate 110 does not coincide with the projection of the core hole 210 onto the first end plate 110, the distance between the projection of the core hole 210 onto the first end plate 110 and the weak portion 1111 is further 2mm-15mm. For example, the distance between the projection of the core hole 210 onto the first end plate 110 and the weak portion 1111 is D1, where the two boundaries of D1 are the sides of the core hole 210 and the weak portion 1111 facing each other radially along the cylindrical battery 10, respectively.

[0070] In this embodiment, by designing the distance between the projection of the core hole 210 on the first end plate 110 and the weak part 1111 to be 2mm-15mm, firstly, it is beneficial for the timely pressure relief of the cylindrical battery; secondly, it is beneficial for controlling the pressure relief rate of the cylindrical battery within a reasonable and safe range, so as to avoid the problem of thermal runaway propagation.

[0071] For example, D1 can be 2mm, 3mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm or 15mm; of course, the embodiments of this application do not limit this, and can be reasonably selected within the above range.

[0072] It should be noted that when the D1 value is too small (e.g., less than 2 mm), it is not conducive to timely pressure relief. When the D1 value is too large (e.g., greater than 15 mm), firstly, it is easy to cause insufficient mechanical strength of the first end plate 110; secondly, when the D1 value is too large, in the later stage of pressure relief of the cylindrical battery 10, it is easy to cause external oxygen to enter the interior of the cylindrical battery 10, which may easily cause secondary combustion or even explosion of the cell 200 residue inside the cylindrical battery 10.

[0073] Reference Figure 2 , Figure 4 and Figure 5 As shown, in some embodiments, the core hole 210 is misaligned with at least one first through hole 301 of the current collector 300. It should be noted that this misalignment refers to the misalignment of the projections of the core hole 210 and the first through hole 301 in the cross-section of the cylindrical battery 10 (the section perpendicular to the axis of the cylindrical battery 10). This misalignment is complete.

[0074] In this embodiment, the core hole 210 and at least one first through hole 301 of the current collector 300 are misaligned to disperse the airflow flowing through the corresponding current collector 300 during the pressure relief process. This prevents the pressure relief airflow from flowing entirely through the area of ​​the current collector 300 that overlaps with the projection of the core hole 210 (understandably, the pressure relief airflow usually has a large amount of heat). This helps to avoid the problem of local overheating of the corresponding current collector 300, thus preventing abnormal melting of the current collector 300 at the position opposite to the core hole 210, and ensuring the current transmission of the cylindrical battery 10.

[0075] Reference Figure 2 , Figure 4 and Figure 5 As shown, in some embodiments, when the core hole 210 and at least one first through hole 301 of the current collector 300 are misaligned, the distance between the core hole 210 and the first through hole 301 is further 2mm-30mm. For example, the distance between the core hole 210 and the first through hole 301 is D2, where the two boundaries of D2 are the sides of the core hole 210 and the first through hole 301 facing each other radially along the cylindrical battery 10; D2 can be understood as the misalignment distance.

[0076] In this embodiment, when D2 is within the above range, it is beneficial to reasonably disperse the airflow flowing through the corresponding current collector 300 to avoid the problem of abnormal melting of the corresponding current collector 300; it can also avoid the flow path of the pressure relief airflow being too large, so as to facilitate timely pressure relief of the cylindrical battery 10.

[0077] For example, the value of D2 can be 2mm, 6mm, 10mm, 14mm, 18mm, 22mm, 26mm or 30mm. Of course, the embodiments of this application do not limit this, and it can be reasonably selected within the above range.

[0078] It should be noted that when the D2 value is too large (i.e., greater than 30mm), it is easy to cause the pressure relief path to be too long, which is not conducive to timely pressure relief; when the D2 value is too small (i.e., less than 2mm), it is easy to cause the heat to concentrate in the central area of ​​the corresponding manifold 300, which is easy to cause the manifold 300 to melt abnormally.

[0079] Reference Figure 2 , Figure 7 , Figure 8 , Figure 9 and Figure 10As shown, in some embodiments, the end face of the battery cell 200 has an exposed area 201, which is not blocked by the current collector 300, and the exposed area 201 is connected to the core hole 210. In other words, the projection of the exposed area 201 on the first end plate 110 is offset from the projection of the current collector 300 on the first end plate 110, and the projection of the exposed area 201 on the first end plate 110 at least partially coincides with the projection of the core hole 210 on the first end plate 110.

[0080] In this embodiment, by providing an exposed area 201, a larger gas flow area can be provided when the cylindrical battery 10 is depressurized, so as to further improve the depressurization rate.

[0081] Understandably, the exposed area 201 can be the area where the battery cell 200 is exposed through the corresponding first through hole 301; or, the exposed area 201 can be the area where the battery cell 200 is not covered by the current collector 300 located between the first end plate 110 and the battery cell 200.

[0082] For example, when the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery 10 along the axial direction, the positive current collector 300a and the negative current collector 300b can be connected by the insulating connector 600, and the aforementioned exposed area 201 can be opposite to the insulating connector 600 along the axial direction of the cylindrical battery 10. It should be noted that the insulating connector 600 is made of a material that can be melted or burned through at high temperatures. During the depressurization process of the cylindrical battery 10, heat is released, and the heat released by the cylindrical battery 10 can burn through or melt the portion of the insulating connector 600 opposite to the corresponding exposed area 201, thus forming a channel for gas flow. It should also be noted that during the welding production operation of the cylindrical battery 10, active heat dissipation (e.g., liquid cooling measures are provided at the corresponding positions of the tooling fixture) can be used to prevent heat from flowing to the insulating connector 600, thereby maintaining the shape of the insulating connector 600 during the production stage of the cylindrical battery 10.

[0083] For example, the insulating connector 600 includes a first slot 601 and a second slot 602. At least a portion of the circumferential edge of the positive current collector 300a is adapted to be inserted into the first slot 601 for mounting in the insulating connector 600. At least a portion of the circumferential edge of the negative current collector 300b is adapted to be inserted into the second slot 602 for mounting in the insulating connector 600. A portion of the first through hole 301 may be located in either the first slot 601 or the second slot 602.

[0084] For example, the insulating connector 600 may have a second through hole 610, which can serve as a channel for pressure relief gas to pass through the insulating connector 600 before the insulating connector 600 melts.

[0085] It should be noted that the exposed area 201 is located outside the area formed between the current collector 300 and the electrode 400. In the exposed area 201, the cell 200 and the corresponding current collector 300 have a gap along the opposite end faces of the cylindrical battery 10, which is used to connect the exposed area 201 with the core hole 210.

[0086] Reference Figure 3 and Figure 4 As shown, in some embodiments, the diameter of the cross-section of the core hole 210 (the cross-section perpendicular to the axial direction of the cylindrical battery 10) is 2mm-10mm. In this way, (S1×S2) / (S0×S0) can be reasonably optimized, so that the cylindrical battery 10 can have the technical effect of timely pressure relief while maintaining the advantage of the energy density of the cylindrical battery 10.

[0087] For example, the diameter of the cross-section of the core hole 210 can be 2mm, 4mm, 6mm, 8mm or 10mm; of course, the embodiments of this application do not limit this, and can be reasonably selected within the above range according to the needs.

[0088] It should be noted that when the diameter of the cross-section of the core hole 210 is too large (for example, greater than 10mm), it is easy to cause a waste of internal space in the cylindrical battery 10, which is not conducive to maintaining the energy density advantage of the cylindrical battery 10; when the diameter of the cross-section of the core hole 210 is too small (for example, less than 2mm), it is not conducive to timely discharge of gas generated by the cell 200, which is easy to cause untimely pressure relief.

[0089] In some embodiments, the cross-sectional area (perpendicular to the axial direction of the cylindrical battery 10) of the winding hole 210 is 3.14 mm². 2 -78.5 mm 2 In this way, (S1×S2) / (S0×S0) can be reasonably optimized, enabling the cylindrical battery 10 to have the technical effect of timely pressure relief while maintaining the advantage of the cylindrical battery 10's energy density.

[0090] For example, the cross-sectional area of ​​the core hole 210 is 3.14 mm². 2 -78.5mm 2 It can be 3.14mm 2 12.56mm 2 28.26 mm 2 50.24 mm 2 Or 78.5mm 2 Of course, the embodiments of this application do not limit this, and can be reasonably selected within the above range according to needs.

[0091] It should be noted that when the diameter of the cross-section of the core hole 210 is too large (e.g., greater than 78.5mm), 2 When the diameter of the core hole 210 is too small (e.g., less than 3.14 mm), it can easily lead to wasted internal space in the cylindrical battery 10, which is detrimental to maintaining the energy density advantage of the cylindrical battery 10. 2 This makes it difficult to release the gas produced by the battery cell 200 in a timely manner, which can easily lead to problems with untimely pressure relief.

[0092] Reference Figure 1 , Figure 11 , Figure 12 and Figure 13 As shown, in some embodiments, the battery cell 200 includes a first tab 221 extending from one end of the battery cell 200 toward the first end plate 110. The distance between the core hole 210 and the free end of the first tab 221 along the radial direction of the housing 100 is 0.5mm-10mm. For example, this distance is D3, where the two boundaries of D3 are the sides along the radial direction of the housing 100 where the core hole 210 and the first tab 221 face each other. It should be noted that the free end of the first tab 221 refers to the end of the first tab 221 that is away from the main body of the battery cell (i.e., the main structure of the battery cell 200 excluding the tab).

[0093] In this embodiment, by setting the distance of D3, the corresponding end face of the cell 200 is exposed in the area near the winding hole 210 to the first electrode tab 221. It can be understood that the gas generated in the cell 200 can flow out from the exposed part, so as to further improve the pressure relief capability of the cylindrical battery 10.

[0094] For example, the value of D3 can be 0.5mm, 1mm, 3mm, 4mm, 6mm, 8mm or 10mm; of course, the embodiments of this application do not limit this, and the setting can be reasonably selected within the above range.

[0095] It should be noted that when the D3 value is too large (e.g., greater than 10mm), the area for interconnection between the first electrode tab 221 and the cell 200 will be sacrificed, which can easily lead to a problem of insufficient current-carrying area, which can further lead to an excessively high resistance value at that point, and an excessively high amount of heat generated at that point. When the D3 value is too small (e.g., less than 0.5mm), it can easily lead to a problem of untimely venting on the corresponding side of the cell 200.

[0096] It should be noted that when the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery along the axial direction, the first electrode tab 221 includes both a positive electrode tab (which can be used to connect the positive current collector 300a) and a negative electrode tab (which can be used to connect the negative current collector 300b). Understandably, at this time, the distance between the free end of the positive electrode tab and the core hole 210 is 0.5mm-10mm; and the distance between the free end of the negative electrode tab and the core hole 210 is 0.5mm-10mm.

[0097] It should be noted that when the positive current collector 300a and the negative current collector 300b are located at both ends of the cylindrical battery, the first tab 221 mentioned above refers only to the corresponding tab (either the positive tab or the negative tab) provided on the end of the cylindrical battery where the pressure relief valve 111 is installed.

[0098] It should be noted that the first electrode ear 221 is used to connect with the corresponding current collector 300.

[0099] Reference Figure 2 , Figure 12 and Figure 13 As shown, in some embodiments, when the battery cell 200 includes a first tab 221, and the first tab 221 extends from one end of the battery cell 200 toward the first end plate 110, the root of the first tab 221 is further spaced apart from the outer edge of the end face of the battery cell 200. The radial distance between the root of the first tab 221 and the outer edge of the end face of the battery cell 200 in the housing 100 is 0.1mm-4mm. For example, this distance is D4. It should be noted that the root of the first tab 221 refers to the end of the first tab 221 that is connected to the battery cell body.

[0100] In this embodiment, by setting the distance of D4, the corresponding end face of the cell 200 is exposed in the area near the housing 100 to the first tab 221. It can be understood that the gas generated in the cell 200 can flow out from the exposed part, so as to further improve the pressure relief capability of the cylindrical battery 10.

[0101] For example, the value of D4 can be 0.1mm, 0.5mm, 1mm, 2mm, 3mm or 4mm. Of course, the embodiments of this application do not limit this, and it can be reasonably selected within the above range.

[0102] It should be noted that when the D4 value is too large (e.g., greater than 4mm), the area where the first electrode tab 221 connects to the cell 200 will be sacrificed, which can easily lead to a problem of insufficient current-carrying area, which can further lead to an excessively high resistance value at that point, and an excessively high amount of heat generated at that point. When the D4 value is too small (e.g., less than 0.1mm), it can easily lead to a problem of untimely venting on the corresponding side of the cell 200.

[0103] Reference Figure 1 , Figure 12 and Figure 13 As shown, in some embodiments, the distance between the end of the core hole 210 and the weak portion 1111 of the pressure relief valve 111 along the axial direction of the housing 100 is 1mm-5mm. For example, this distance can be referenced to D5, where the two boundaries of D5 are the weak portion 1111 and the end of the core hole 210 facing each other in the axial direction of the housing 100, respectively.

[0104] In this embodiment, by designing D5 to be between 1mm and 5mm, firstly, it facilitates the compactness of the internal space layout of the cylindrical battery 10, so as to fully utilize the high energy density of the cylindrical battery 10; secondly, it optimizes the flow path of the airflow from the core hole 210 to the pressure relief area of ​​the pressure relief valve 111, so as to facilitate the timely pressure relief of the cylindrical battery 10.

[0105] For example, the value of D5 can be 1mm, 2mm, 3mm, 4mm or 5mm; of course, the embodiments of this application do not limit this, and can be reasonably selected within the above range.

[0106] It should be noted that when D5 is too large (e.g., greater than 5mm), it can easily lead to a waste of the internal space of the cylindrical battery 10, which is not conducive to the cylindrical battery 10 fully utilizing its high energy density advantage; when D5 is too small (e.g., less than 1mm), it can easily cause excessive resistance when the airflow flows from the cell 200 to the pressure relief valve 111, which is not conducive to the timely pressure relief of the cylindrical battery 10.

[0107] Reference Figure 1 , Figure 5 , Figure 10 and Figure 11 As shown, in some embodiments, the battery cell 200 further includes a first tab 221, which extends from one end of the battery cell 200 toward the first end plate 110 and is welded to the current collector 300. The projection of the winding hole 210 and the first tab 221 onto the first end plate 110 does not coincide. It should be noted that this non-coincidence refers to their complete misalignment.

[0108] In this embodiment, the design of not coinciding the projection of the winding hole 210 and the first tab 221 on the first end plate 110 avoids the first tab 221 from blocking the winding hole 210, so as to facilitate the timely pressure relief of the cylindrical battery 10.

[0109] It should be noted that when the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery along the axial direction, the first electrode tab 221 includes both a positive electrode tab (which can be used to connect the positive current collector 300a) and a negative electrode tab (which can be used to connect the negative current collector 300b). Understandably, at this time, the distance between the free end of the positive electrode tab and the core hole 210 is 1mm-5mm; and the distance between the free end of the negative electrode tab and the core hole 210 is 1mm-5mm.

[0110] It should be noted that when the positive current collector 300a and the negative current collector 300b are located at both ends of the cylindrical battery, the first tab 221 mentioned above refers only to the corresponding tab (either the positive tab or the negative tab) provided on the end of the cylindrical battery where the pressure relief valve 111 is installed.

[0111] Reference Figure 2 , Figure 4 , Figure 5 , Figure 7 , Figure 10 and Figure 11 As shown, in some embodiments, the current collector 300 includes a first welding area 302 and a second welding area 303. The first welding area 302 is welded to the tab portion 220 of the cell 200, and the second welding area 303 is welded to the electrode 400 of the cylindrical battery 10. A first through hole 301 is disposed between the first welding area 302 and the second welding area 303.

[0112] It should be noted that the first welding area 302 is suitable for connection with the corresponding tab 220, and the second welding area 303 is connected with the electrode 400 of the cylindrical battery 10. The first welding area 302 and the second welding area 303 need to be connected to the corresponding positions, so it is difficult for the first welding area 302 and the second welding area 303 to form the gap mentioned above for gas to flow through. However, by setting the first through hole 301 between the first welding area 302 and the second welding area 303, it is convenient to form the gap mentioned above for depressurized gas to flow through in the corresponding area, so as to achieve the effect of timely depressurization.

[0113] For example, when the positive current collector 300a and the negative current collector 300b are located at the same end of the axial direction of the cylindrical battery 10, both the positive current collector 300a and the negative current collector 300b may have a first welding area 302. Accordingly, the first welding area is adapted to be welded to the corresponding tab portion 220 (the positive current collector 300a is connected to the positive tab, and the negative current collector 300b is connected to the negative tab).

[0114] For example, when the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery 10 along the axial direction, the second welding area 303 of the negative current collector 300b can be a stamped protrusion formed on the negative current collector 300b, which is located approximately at the axial center of the cylindrical battery 10, and the stamped protrusion faces the terminal post protrusion and is welded to the terminal post 410; the second welding area 303 of the positive current collector 300a can be its annular protrusion, which is located approximately near the edge of the housing body 101; the annular protrusion faces the first end plate 110 along the axial direction of the cylindrical battery 10, and the annular protrusion is welded to the first end plate 110 of the cylindrical battery 10.

[0115] Reference Figure 2 , Figure 4 , Figure 5 , Figure 7 , Figure 10 and Figure 11 As shown, in some embodiments, when the current collector 300 includes a first welding area 302 and a second welding area 303, the first welding area 302 is welded to the tab portion 220 of the cell 200, and the second welding area 303 is welded to the electrode 400 of the cylindrical battery 10; and a first through hole 301 is disposed between the first welding area 302 and the second welding area 303, further, the sum of the areas of the first through holes 301 is 3.14 mm. 2 ≤S1≤452.63mm 2 .

[0116] In this embodiment, by using 3.14mm 2 ≤S1≤452.63mm 2 On the one hand, this helps to ensure the mechanical strength of the current collector 300 located outside the first welding area 302 and the second welding area 303; on the other hand, it helps to ensure that there is a sufficient current flow area between the first welding area 302 and the second welding area 303, so as to avoid excessive resistance between the first welding area 302 and the second welding area 303 and avoid abnormal heating of the current collector 300.

[0117] It should be noted that during the conduction process of the current collector 300, the current needs to flow from the area between the first welding area 302 and the second welding area 303. When S1 is too large (for example, greater than 452.63 mm), 2 When S1 is too small (e.g., less than 3.14 mm), it can easily cause excessive resistance in the area between the first welding area 302 and the second welding area 303, which can easily lead to abnormal heat generation in the current collector 300. 2 (At this time), it can easily cause problems with untimely pressure relief.

[0118] For example, the value of S1 can be 3.14 mm. 212.56 mm 2 15.7 mm 2 28.26 mm 2 50.24mm 2 62.8mm 2 78.5 mm 2 141.3 mm 2 204.1 mm 2 304.58 mm 2 383.08 mm 2 Or 452.63mm 2 Of course, the embodiments in this application do not impose any limitations on this, and reasonable choices can be made within the above-mentioned range.

[0119] Reference Figure 2 , Figure 4 , Figure 5 , Figure 7 , Figure 10 and Figure 11 As shown, in some embodiments, the current collector 300 includes a first welding area 302, which is welded to the tab portion 220 of the battery cell 200; the first through hole 301 and the first welding area 302 are arranged circumferentially around the housing 100.

[0120] In this embodiment, the above-mentioned scheme can stagger the first through hole 301 and the first welding area 302 of the corresponding current collector 300 where the first through hole 301 is located, which is beneficial to ensure the welding effect and welding strength of the first welding area 302.

[0121] For example, when the positive current collector 300a and the negative current collector 300b are located at the same end of the axial direction of the cylindrical battery 10, both the positive current collector 300a and the negative current collector 300b may have a first welding area 302. Accordingly, the first welding area is adapted to be welded to the corresponding tab portion 220 (the positive current collector 300a is connected to the positive tab, and the negative current collector 300b is connected to the negative tab).

[0122] For example, when the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery 10 along the axial direction, the second welding area 303 of the negative current collector 300b can be a stamped protrusion formed on the negative current collector 300b, which is located approximately at the axial center of the cylindrical battery 10. The stamped protrusion includes a protrusion facing the terminal post 410 and is welded to the terminal post 410. The second welding area 303 of the positive current collector 300a can be an annular protrusion, which is located approximately near the edge of the housing body 101. The annular protrusion is located facing the first end plate 110 along the axial direction of the cylindrical battery 10 and is welded to the first end plate 110 of the cylindrical battery 10.

[0123] Reference Figure 2 , Figure 4 , Figure 5 , Figure 7 and Figure 10 As shown, in some embodiments, when the current collector 300 includes a first welding area 302, the first welding area 302 is welded to the tab portion 220 of the battery cell 200; and the first through hole 301 and the first welding area 302 are spaced apart along the circumference of the housing 100, further, there are at least two first through holes 301, and the at least two first through holes 301 are respectively provided on opposite sides of the first welding area 302 along the circumference of the housing 100.

[0124] In this embodiment, on the one hand, the airflow flowing through the corresponding current collector 300 can be dispersed on both sides of the corresponding first welding area 302 to disperse the heat of the depressurized airflow borne by the current collector 300, thus avoiding heat concentration that could damage the corresponding welding position; on the other hand, it helps to reduce the resistance difference between the corresponding current collector 300 on both sides of the first welding area 302, so as to avoid the problem of deformation of the first welding area 302 due to uneven heating of the current collector 300.

[0125] It should be noted that when the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery 10 along the axial direction, and when the first through hole 301 is provided only in the positive current collector 300a, the at least two first through holes 301 provided on the positive current collector 300a are located on both sides of the first welding area 302 of the positive current collector 300a.

[0126] When the positive current collector 300a and the negative current collector 300b are located at the same end of the axial direction of the cylindrical battery 10, and when the first through hole 301 is provided only in the negative current collector 300b, at least two first through holes 301 provided on the negative current collector 300b are located on both sides of the first welding area 302 of the negative current collector 300b.

[0127] When the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery 10 along its axial direction, and when both the positive current collector 300a and the negative current collector 300b are provided with a first through hole 301; the number of first through holes 301 on the positive current collector 300a is at least two, and these first through holes 301 on the positive current collector 300a are distributed on both sides of the first welding area 302 of the positive current collector 300a. The number of first through holes 301 on the negative current collector 300b is at least two, and these first through holes 301 on the negative current collector 300b are distributed on both sides of the first welding area 302 of the negative current collector 300b.

[0128] Reference Figure 1 , Figure 2 , Figure 5and Figure 6 As shown, in some embodiments, the pressure relief valve 111 includes a weak portion 1111, and the projection of the first through hole 301 on the first end plate 110 at least partially coincides with the weak portion 1111.

[0129] In this embodiment, through the first through hole 301 whose projection on the first end plate 110 coincides with the weak part 1111, the cylindrical battery 10 can be quickly vented through the first through hole 301 in the early stage of the pressure relief valve 111 tearing, so as to further relieve the pressure of the cylindrical battery 10 in a timely manner.

[0130] Reference Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, in some embodiments, the pressure relief valve 111 includes a weak portion 1111, the projection of the first through hole 301 on the first end plate 110 is offset from the weak portion 1111, and the area of ​​the core hole 210 is 4.52 mm². 2 ≤S2≤78.5mm 2 .

[0131] In this embodiment, by designing the projection of the first through hole 301 on the first end plate 110 to be misaligned with the weak part 1111, the gas pressure acting on the first end plate 110 is more likely to generate a torque effect on the weak part 1111, so that the weak part 1111 is torn in time when the pressure reaches the set value, so as to release the pressure of the cylindrical battery in time.

[0132] For example, in this embodiment, S2 can be 4.52mm. 2 12.56 mm 2 28.26 mm 2 50.24 mm 2 Or 78.5 mm 2 Of course, this application does not limit this, and you can make reasonable choices within the above range according to your needs.

[0133] Reference Figure 2 , Figure 10 and Figure 11 As shown, in some embodiments, the end face of the battery cell 200 includes an exposed area 202 not covered by the tab portion 220, and the first through hole 301 is disposed opposite to the exposed area 202.

[0134] Understandably, the exposed area 202 can be used for the cell 200 to vent in the direction of the first end plate 110, so as to improve the venting efficiency of the cell 200. The exposed area 202 is set opposite to the first through hole 301 to further improve the timeliness of the cylindrical battery 10 to depressurize.

[0135] Reference Figure 2 , Figure 5 , Figure 7 and Figure 10 As shown, in some embodiments, the current collector 300 includes a first welding area 302 and a non-welding area 304. The first welding area 302 is welded to the tab portion 220 of the battery cell 200, and the thickness of the first welding area 302 is less than the thickness of the non-welding area 304.

[0136] In this embodiment, by reducing the thickness of the first welding area 302 corresponding to the current collector 300, when the pressure relief valve 111 tears and flips, the side of the first welding area 302 adjacent to the pressure relief valve 111 in the radial direction of the cylindrical battery 10 can be torn apart relative to the non-welded area 304. In this way, on the one hand, it can reduce the flipping resistance of the corresponding part of the pressure relief valve 111 during the pressure relief process, which is conducive to the timely reversal of the corresponding part of the pressure relief valve 111; on the other hand, when the cylindrical battery is depressurized, it can prevent the first welding area 302 from detaching from the corresponding tab 220, and reduce the large displacement of the non-welded area 304 relative to the pressure relief valve 111 when it flips. Thus, the risk of short circuit of the corresponding current collector 300 can be avoided during the pressure relief process of the cylindrical battery 10.

[0137] For example, when the positive current collector 300a and the negative current collector 300b are located at the same end of the axial direction of the cylindrical battery 10: the thickness of the first welding area 302 on the positive current collector 300a can be set to be less than the thickness of the non-welded area 304 of the positive current collector 300a; or, the thickness of the first welding area 302 on the negative current collector 300b can be set to be less than the thickness of the non-welded area 304 of the negative current collector 300b; or, both the thickness of the first welding area 302 on the positive current collector 300a and the thickness of the first welding area 302 on the negative current collector 300b can be set to be less than the thickness of the non-welded area 304 of the positive current collector 300a.

[0138] Reference Figure 2 , Figure 5 , Figure 7 , Figure 10 and Figure 11 As shown, in some embodiments, when the current collector 300 includes a first welding area 302 and a non-welding area 304, the first welding area 302 is welded to the tab portion 220 of the battery cell 200, and the thickness of the first welding area 302 is less than the thickness of the non-welding area 304, a first through hole 301 is further provided in the non-welding area 304.

[0139] Understandably, in this embodiment, by placing the first through hole 301 in the non-welding area 304, the first through hole 301 is avoided from affecting the area of ​​the first welding area 302, so as to ensure that there is sufficient contact area between the first welding area 302 and the corresponding electrode tab 220, so as to avoid the electrothermal problem caused by the reduction of the first welding area 302.

[0140] Reference Figure 2 As shown, in some embodiments, the melting point of the current collector 300 is less than or equal to 670°C. It is understood that in this embodiment, by employing a current collector 300 with a melting point within the aforementioned range, the electrical connection between the cylindrical battery 10 and the external environment (e.g., other batteries) can be promptly severed when a short circuit or localized overheating occurs, thereby achieving the technical effect of isolating the corresponding cylindrical battery 10 and preventing damage to other batteries connected to it by the short-circuit current.

[0141] For example, the melting point of the current collector can be 670°C, 500°C, 400°C or 300°C, etc. Of course, the embodiments of this application do not limit this, as long as it is within the above range and can meet the usage requirements of the corresponding battery.

[0142] Reference Figure 1 As shown, in some embodiments, the pressure relief valve 111 includes a weak portion 1111; the weak portion 1111 is formed as an annular groove. It should be noted that the annulus can be approximately centered on the axis of the cylindrical battery 10. It can be understood that the annular groove is continuous in the circumferential direction.

[0143] Or, refer to Figure 12 The weak part 1111 is formed as a discontinuous groove, and the distance between the two ends of the weak part 1111 is 2mm-20mm, where the distance between the two ends of the weak part 1111 refers to the straight-line distance. This ensures the opening degree of the pressure relief valve 111 while preventing it from flying out after opening. For example, this distance is D6, which can be 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, or 20mm; of course, it can be reasonably selected within the above range. When D6 is too small (e.g., less than 2mm), the pressure relief valve 111 is prone to flying out after opening (which can easily cause a short circuit to other batteries or circuits); when D6 is too large (e.g., greater than 20mm), it can easily cause insufficient opening degree of the pressure relief valve 111.

[0144] In this embodiment, when the pressure reaches the set value, the weak part 1111 of the pressure relief valve 111 is torn apart to achieve the effect of pressure relief.

[0145] Reference Figure 5 and Figure 6As shown, in some embodiments, the first end plate 110 includes a first recess 112, which has a bottom wall 1121. The pressure relief valve 111 includes a weak portion 1111, which is disposed on the bottom wall 1121. In this embodiment, by disposing the weak portion 1111 on the bottom wall 1121 of the first recess 112, the mechanical strength of the corresponding area of ​​the first end plate 110 (such as the non-pressure relief area and the area that does not need to be torn) is ensured, while the weak portion 1111 has the lowest possible thickness. This allows the gas pressure inside the cylindrical battery 10 to push the pressure relief valve 111 to tear the weak portion 1111 in time to relieve pressure when the cylindrical battery 10 needs to be depressurized.

[0146] Reference Figure 2 , Figure 7 , Figure 8 , Figure 10 , Figure 11 and Figure 12 As shown, in some embodiments, the tab portion 220 includes a positive tab 220a and a negative tab 220b, which are located at the same end of the battery cell 200. The ratio of the sum of the areas of the first through holes 301 to the area of ​​the current collector 300 is 0.01-0.2; for example, this ratio can be 0.01, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18 or 0.2. Of course, the embodiments of this application do not limit this, and reasonable selections can be made within the above range. It is understood that when the ratio is too large (for example, greater than 0.2), it is easy to cause the resistance of the corresponding current collector 300 to be too large, which can easily lead to the problem of excessive heating of the corresponding current collector 300; when the ratio is too small (for example, less than 0.01), the gas flow resistance is large during depressurization, which is not conducive to timely depressurization.

[0147] Understandably, in this embodiment, the positive tab 220a and the negative tab 220b, the positive current collector 300a and the negative current collector 300b are located at the same end of the cylindrical battery 10 along its axial direction.

[0148] In this embodiment, the positive electrode tab 220a and negative electrode tab 220b, the positive electrode current collector 300a and the negative electrode current collector 300b are located at the same end of the cylindrical battery 10 along the axial direction, which facilitates timely pressure relief of the cylindrical battery 10 and avoids unreasonable heating problems.

[0149] In some embodiments, the tab portion 220 includes a positive tab 220a and a negative tab 220b, which are located at both ends of the cell 200 along the axial direction of the housing 100.

[0150] In this embodiment, the positive electrode tab 220a and the negative electrode tab 220b are located at both ends of the axial direction of the cylindrical battery 10; and the positive current collector 300a and the negative current collector 300b are located at both ends of the axial direction of the cylindrical battery 10, so that the cylindrical battery 10 can release pressure in a timely manner and avoid unreasonable heating problems.

[0151] Understandably, in this embodiment, the positive electrode tab 220a and the negative electrode tab 220b are located at both ends of the cylindrical battery 10 along the axial direction. Correspondingly, the positive current collector 300a and the negative current collector 300b are located at both ends of the cylindrical battery 10 along the axial direction. In this case, the first through hole 301 is provided on the corresponding current collector 300 at the corresponding end of the cylindrical battery 10 with the pressure relief valve 111.

[0152] Reference Figure 2 and Figure 7 As shown, in some embodiments, the sum of the areas S1 of the first through holes 301 is 3.14 mm. 2 -603.51mm 2 .

[0153] Understandably, S1 is 3.14 mm. 2 -603.51mm 2 This ensures timely pressure relief while avoiding unreasonable heating issues.

[0154] For example, in this embodiment, S1 can be 3.14 mm. 2 12.56 mm 2 15.7 mm 2 28.26 mm 2 50.24mm 2 62.8 mm 2 78.5 mm 2 141.3 mm 2 204.1 mm 2 304.58 mm 2 383.08 mm 2 452.63mm 2 502.87 mm 2 581.37 mm 2 Or 603.51mm 2 Of course, this embodiment does not impose any restrictions on this, and reasonable choices can be made within the above range.

[0155] It should be noted that when S1 is too small (e.g., less than 3.14), the gas flow resistance is high during the depressurization process, which is not conducive to timely depressurization. When S2 is too large (e.g., greater than 603.51 mm), the gas flow resistance is high. 2When the current is too high, it can easily cause the resistance of the corresponding current collector 300 to be too high, which can easily lead to unreasonable heating problems.

[0156] Reference Figure 10 As shown, in some embodiments, the area S0 of the end face of the battery cell 200 is 314 mm. 2 -3017.54mm 2 Understandably, this is suitable for the size of mainstream cylindrical batteries 10. For example, S0 could be 314 mm. 2 530.66mm 2 803.84 mm 2 1133.54 mm 2 1519.76 mm 2 1962.5 mm 2 2461.76 mm 2 Or 3017.54 mm 2 Of course, the embodiments of this application do not limit this, and reasonable choices can be made within the above range.

[0157] Reference Figure 10 As shown, in some embodiments, the cross-sectional area S2 of the core hole 210 is 3.14 mm. 2 -78.5mm 2 Thus, the size is suitable for mainstream cylindrical batteries 10. An exemplary S2 could be 3.14 mm. 2 12.56 mm 2 28.26mm 2 50.24 mm 2 Or 78.5mm 2 Of course, this application does not limit this, and reasonable choices can be made within the above range.

[0158] Reference Figure 1 , Figure 4 , Figure 5 and Figure 10 As shown, in some embodiments, when the diameter of the cylindrical battery 10 is greater than or equal to 40 mm or the axial height of the cylindrical battery 10 is greater than or equal to 70 mm, and the diameter of the cylindrical battery 10 is greater than or equal to 40 mm or the axial height of the cylindrical battery 10 is greater than or equal to 70 mm, 0.44 × 10 -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3 Here, (S1×S2) / (S0×S0) can be 0.44×10 -3 0.89×10 -3 1.41×10 -3 2.25×10-3 2.69×10 -3 3.70×10 -3 5.27×10 -3 6.81×10 -3 Or 11.25×10 -3 Of course, this application example does not impose any restrictions on this, and reasonable choices can be made within the above range.

[0159] In this embodiment, (S1×S2) / (S0×S0) is set to 0.44×10 -3 Up to 11.25×10 -3 This facilitates timely pressure release of the cylindrical battery 10 that meets the above size range and avoids unreasonable heating problems.

[0160] Reference Figure 1 , Figure 2 , Figure 4 , Figure 5 and 7 As shown, in some embodiments, the projection of the first through hole 301 or the core hole 210 on the first end plate 110 is completely located in the area surrounded by the pressure relief valve 111; or, the projections of both the first through hole 301 and the core hole 210 on the first end plate 110 are completely located in the area surrounded by the pressure relief valve 111.

[0161] Reference Figure 1 , Figure 2 , Figure 4 , Figure 5 and 7 In this embodiment, during the depressurization process, it is beneficial for the depressurized gas to flow outward in a timely manner through the first through hole 301 or the core hole 210 that is opposite to the depressurization valve 111 along the axial direction of the cylindrical battery 10, so as to further reduce the flow path of the depressurized gas and further ensure the timeliness of depressurization of the cylindrical battery 10.

[0162] Reference Figure 1 , Figure 4 and Figure 5 As shown, in some embodiments, the cylindrical battery 10 may further include a terminal post 410 and an insulating assembly 500. The terminal post 410 passes through the first end plate 110. The insulating assembly 500 is disposed between the terminal post 410 and the first end plate 110. It is understood that the insulating assembly 500 is used to insulatingly separate the terminal post 410 from the first end plate 110, preventing a short circuit between the terminal post 410 and the first end plate 110. For example, the insulating assembly 500 may include a first insulating ring 510 and a second insulating ring 520. For example, a portion of the area between the terminal post 410 and the first end plate 110 may also be insulated and separated by a portion of the insulating connector 600 mentioned above.

[0163] The current collector 300 includes a positive current collector 300a and a negative current collector 300b. One of the terminal post 410 and the first end plate 110 is connected to the positive current collector 300a to serve as the positive electrode of the cylindrical battery 10; the other of the terminal post 410 and the first end plate 110 is connected to the negative current collector 300b to serve as the negative electrode of the cylindrical battery 10. The electrode 400 includes the terminal post 410 and the first end plate 110.

[0164] It is understood that in this embodiment, the positive current collector 300a and the negative current collector 300b of the cylindrical battery 10 are located at the same end of the cylindrical battery 10 along the axial direction.

[0165] In this embodiment, the technical effect of timely pressure relief can be achieved for the positive current collector 300a and the negative current collector 300b located at the same end of the cylindrical battery 10 along the axial direction of the cylindrical battery 10.

[0166] For example, in this embodiment, the terminal 410 is the negative electrode of the cylindrical battery, and the first end plate 110 is the positive electrode of the cylindrical battery 10. Alternatively, in some possible embodiments, the terminal 410 is the positive electrode of the cylindrical battery, and the first end plate 110 is the negative electrode of the cylindrical battery 10.

[0167] Reference Figures 1 to 13 As shown, the following describes the preparation method of a cylindrical battery 10 as a lithium-ion battery, and provides some embodiments and comparative examples of the cylindrical battery 10.

[0168] (1) Preparation of positive electrode sheet: The prepared positive electrode active material, conductive agent (e.g., acetylene black), binder (e.g., PVDF) are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheet is then obtained by rolling and slitting.

[0169] The mass ratio of positive electrode active material: conductive agent: binder satisfies (92-98): (4-1): (4-1).

[0170] (2) Preparation of negative electrode sheet: The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (SBR)) are mixed and deionized water is added as solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector foil, dried at room temperature, and then transferred to an oven for further drying. The negative electrode sheet is then obtained by rolling and slitting.

[0171] (3) Preparation of electrolyte: Ethyl carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0172] (4) Preparation of diaphragm: Polyethylene film is used as diaphragm.

[0173] (5) Preparation of cylindrical battery 10: The above-mentioned positive electrode sheet, separator, and negative electrode sheet are stacked in sequence. The first end formed by the stacking of the positive electrode sheet, separator, and negative electrode sheet is grasped by a winding needle, and the positive electrode sheet, separator, and negative electrode sheet are wound into an electrode roll. After completion, the winding needle is pulled out to form a bare cell. The area where the winding needle is pulled out forms a core hole. The bare cell is placed in the casing 100 of cylindrical battery 10, and the tab is welded to the current collector 300. The current collector 300 is electrically connected to the casing 100 or the electrode post of cylindrical battery 10. The cylindrical battery 10 is dried, electrolyte is injected, and after encapsulation, standing, formation, and volume determination, a lithium-ion cylindrical battery 10 is obtained.

[0174] In the selection of materials for the cylindrical battery 10, this application may also select other materials, not limited to the materials limited by the above preparation method. The positive electrode active material may be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt and manganese, and lithium manganese iron phosphate; the negative electrode active material may be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0175] Conductive agents include, but are not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene, and carbon nanofibers.

[0176] The adhesive includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0177] The solvent can be deionized water, NMP (N-methylpyrrolidone), alcohol, ether, ketone or other types of pyrrolidone, etc.

[0178] The positive electrode current collector foil can be a metal foil or a composite current collector. For example, as a metal foil, it can be made of stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0179] The negative electrode current collector foil can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium, and can be surface-plated with silver. Composite current collectors may include a polymer base layer and a metal layer. Composite current collectors can be formed by forming metal materials (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer base material (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0180] The cylindrical battery 10 prepared by the above method was subjected to the following tests:

[0181] (1) Method for measuring the dimensions and area of ​​the components of the cylindrical battery 10: Use measuring instruments such as micrometers or calipers to measure parameters such as length, width, distance, thickness, and diameter. The area is calculated from the measured parameters such as length, width, distance, thickness, and diameter.

[0182] (2) Test method for the damage ratio of the casing 100 of the cylindrical battery 10:

[0183] Following the above method for preparing the cylindrical battery 10, 150 cylindrical batteries 10 were prepared for each embodiment and comparative example. These prepared cylindrical batteries 10 were used as samples, and all other test conditions remained consistent. The cylindrical batteries 10 were charged at a current of 1C until the upper voltage limit was reached, and then charged at a constant voltage until the current dropped to 0.05C.

[0184] A heating element is placed on the circumference of the casing 100 of the cylindrical battery 10, and the triggering object is heated at the maximum power of the heating device. When thermal runaway occurs or the temperature at the monitoring point reaches 300°C, triggering is stopped and the heating device is turned off. The thermal runaway determination criteria are: the triggering object generates a voltage drop, and the drop value exceeds 25% of the initial voltage; or the temperature rise rate at the monitoring point dT / dt ≥ 1 T / d, and lasts for more than 3 seconds, then thermal runaway is determined to have occurred.

[0185] Record the number N1 of cylindrical batteries 10 that experienced thermal runaway. After the pressure relief is completed, observe the casing 100 of the thermally runaway cylindrical batteries 10 to see if the casing 100 ruptures in an area outside the pressure relief mechanism. Record the number N2 of cylindrical batteries 10 with ruptured casing 100. The percentage of casing 100 damaged during thermal runaway of cylindrical batteries 10 is calculated as (N2 / N1) × 100%. If the percentage of casing 100 damaged during thermal runaway of cylindrical batteries 10 is greater than 4%, it is considered unqualified; if the percentage of casing 100 damaged during thermal runaway of cylindrical batteries 10 is greater than 2% and less than or equal to 4%, it is considered qualified; if the percentage of casing 100 damaged during thermal runaway of cylindrical batteries 10 is less than or equal to 2%, it is considered good.

[0186] The upper and lower voltage limits of cylindrical batteries 10 vary depending on their system: Lithium iron phosphate (LFP) - upper limit 3.65V, lower limit 2.5V; Nickel-cobalt-manganese ternary NCM - upper limit 4.25V, lower limit 2.5V; Lithium manganese iron phosphate (LFMP) - upper limit 4.25V, lower limit 2.5V; Lithium nickel manganese oxide (LiMO) - upper limit 4.8V, lower limit 3.5V.

[0187] The positive electrode active material of the cylindrical battery 10 in this test is selected from nickel-cobalt-manganese ternary LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0188] (3) Test method for the temperature rise rate of cylindrical battery 10:

[0189] Following the above-described method for preparing the cylindrical battery 10, cylindrical batteries 10 were prepared for each embodiment and comparative example. The prepared cylindrical batteries 10 were used as samples, and all other testing conditions remained consistent. At room temperature (20°C), the first end plate 110 of the casing 100 of the cylindrical battery 10 was connected to a temperature sensor.

[0190] Cylindrical battery 10 was discharged at a constant current of 0.33C to the lower limit voltage of 2.5V, and then left to stand for 60 minutes. After standing, the temperature measured by the temperature sensor at this time was recorded as t1. Then, cylindrical battery 10 was charged at 1C to the upper limit voltage of 4.25V, and the time was recorded as T. The temperature measured by the temperature sensor at this time was measured as t2. The temperature rise rate was calculated using the formula: temperature rise rate = (t2 - t1) / T. If the temperature rise rate is greater than 0.9℃ / min, it is unqualified; if the temperature rise rate is less than or equal to 0.9℃ / min and greater than 0.7℃ / min, it is qualified; if the temperature rise rate is less than or equal to 0.7℃ / min, it is good.

[0191] The upper and lower voltage limits of cylindrical batteries 10 vary depending on their system: Lithium iron phosphate (LFP) - upper limit 3.65V, lower limit 2.5V; Nickel-cobalt-manganese ternary NCM - upper limit 4.25V, lower limit 2.5V; Lithium manganese iron phosphate (LFMP) - upper limit 4.25V, lower limit 2.5V; Lithium nickel manganese oxide (LiMO) - upper limit 4.8V, lower limit 3.5V.

[0192] In this test, the positive electrode active material of the cylindrical battery 10 was selected from nickel-cobalt-manganese ternary LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0193] The following table is a statistical table of parameters and performance test results for various embodiments and comparative examples of this application:

[0194]

[0195] Combining Example 1 and Comparative Example 2 in the table above, it can be seen that when the manifold 300 is provided with a first through hole, by controlling (S1×S2) / (S0×S0) to be greater than or equal to 0.06×10 -3 It can better control the proportion of casing 100 rupture under battery thermal runaway, that is, it can improve the venting efficiency under thermal runaway and prevent excessive pressure from causing the casing 100 outside the pressure relief valve 111 to rupture due to excessive pressure.

[0196] Combining Example 11 and Comparative Example 1 in the table above, it can be seen that when the manifold 300 is provided with a first through hole, by controlling (S1×S2) / (S0×S0) to be less than or equal to 11.25×10 -3 It can better control the heating rate at the first end plate 110 of the battery in the working state, that is, it can avoid the situation where the resistance at the current collector 300 is too large and the heat generation is too severe due to the opening of the first through hole.

[0197] As can be seen from Examples 1-14 in the table above, by controlling (S1×S2) / (S0×S0) to be greater than or equal to 0.06×10 -3 And less than or equal to 11.25 × 10 -3In the event of battery thermal runaway, the proportion of casing 100 rupture and the heating rate at the first end plate 110 of the battery in the working state are significantly improved. This ensures timely pressure relief during battery thermal runaway and avoids unnecessary resistance heat generation caused by the first through hole in the current collector 300, thereby improving the overall stability and reliability of the battery.

[0198] The electrical equipment provided in the second aspect of this application includes the battery 10 described above. By incorporating the battery 10, the electrical equipment provided in this application facilitates timely pressure relief of the battery 10, reducing the possibility of thermal runaway or explosion, and promoting the safe operation of the electrical equipment.

[0199] For example, electrical equipment can include: energy storage devices, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace and many other technical fields.

[0200] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A cylindrical battery, characterized in that, include: The housing (100) includes a first end plate (110) located at one end of its own axial direction, and the first end plate (110) is provided with a pressure relief valve (111). A battery cell (200) is disposed inside the housing (100). A winding hole (210) is formed in the middle of the battery cell (200). The winding hole (210) extends along the axial direction of the housing (100). The battery cell (200) includes a body portion (230) and a tab portion (220). At least one tab portion (220) extends from one end of the body portion (230) toward the first end plate (110). A current collector (300) is disposed between the first end plate (110) and the battery cell (200). The current collector (300) is electrically connected to the tab portion (220) and the electrode (400) of the cylindrical battery. The current collector (300) is provided with a first through hole (301), which penetrates the current collector (300) in an axial direction parallel to the housing (100). The projections of the core hole (210) on the plane of the first end plate (110) are at least partially coincident with the pressure relief valve (111); Among them, the sum of the areas of the first through holes (301) S1, the end face area of ​​the battery cell (200) S0, and the cross-sectional area of ​​the winding hole (210) S2 satisfy: 0.06 × 10 -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3 .

2. The cylindrical battery according to claim 1, characterized in that, The projection of the core hole (210) on the first end plate (110) is located inside the pressure relief valve (111).

3. The cylindrical battery according to claim 1, characterized in that, The pressure relief valve (111) includes a weak part (1111) that does not coincide with the projection of the core hole (210) on the first end plate (110).

4. The cylindrical battery according to claim 3, characterized in that, The distance between the projection of the core hole (210) on the first end plate (110) and the weak part (1111) is 2mm-15mm.

5. The cylindrical battery according to claim 1, characterized in that, The core hole (210) and the first through hole (301) are both offset.

6. The cylindrical battery according to claim 5, characterized in that, The closest distance between the core hole (210) and the first through hole (301) is 2mm-30mm.

7. The cylindrical battery according to claim 1, characterized in that, The end face of the cell (200) has an exposed area (201), the projection of the exposed area (201) on the first end plate (110) is offset from the projection of the current collector (300) on the first end plate (110), and the projection of the exposed area (201) on the first end plate (110) at least partially coincides with the projection of the core hole (210) on the first end plate (110).

8. The cylindrical battery according to claim 1, characterized in that, The diameter of the cross-section of the core hole (210) is 2mm-10mm; and / or, the cross-sectional area of ​​the core hole (210) is 3.14mm². 2 -78.5 mm 2 .

9. The cylindrical battery according to claim 1, characterized in that, The battery cell (200) includes a first tab (221) extending from one end of the battery cell (200) toward the first end plate (110). Along the radial direction of the housing (100), the distance between the core hole (210) and the free end of the first pole lug (221) is 0.5mm-10mm.

10. The cylindrical battery according to claim 9, characterized in that, The root of the first electrode tab (221) is spaced apart from the outer edge of the end face of the battery cell (200), and the radial distance between the root of the first electrode tab (221) and the outer edge of the end face of the battery cell (200) in the housing (100) is 0.1mm-4mm.

11. The cylindrical battery according to claim 1, characterized in that, Along the axial direction of the housing (100), the distance between the end of the core hole (210) and the weak part (1111) of the pressure relief valve (111) is 1mm-5mm.

12. The cylindrical battery according to claim 1, characterized in that, The battery cell (200) further includes a first tab (221), which extends from one end of the battery cell (200) toward the first end plate (110) and is welded to the current collector (300). The core hole (210) does not coincide with the projection of the first pole lug (221) on the first end plate (110).

13. The cylindrical battery according to any one of claims 1-12, characterized in that, The current collector (300) includes a first welding area (302) and a second welding area (303). The first welding area (302) is welded to the tab (220) of the cell (200), and the second welding area (303) is welded to the electrode (400) of the cylindrical battery. The first through hole (301) is disposed between the first welding area (302) and the second welding area (303).

14. The cylindrical battery according to claim 13, characterized in that, The sum of the areas of the first through holes (301) is 3.14 mm. 2 ≤S1≤452.63mm 2 .

15. The cylindrical battery according to any one of claims 1-12, characterized in that, The current collector (300) includes a first welding area (302), which is welded to the tab (220) of the battery cell (200); The projections of the first through hole (301) and the first welding area (302) on the first end plate (110) are spaced apart along the circumferential direction of the housing (100).

16. The cylindrical battery according to claim 15, characterized in that, There are at least two first through holes (301), and at least two first through holes (301) are respectively provided on both sides of the first welding area (302) along the circumference of the shell (100).

17. The cylindrical battery according to any one of claims 1-12, characterized in that, The pressure relief valve (111) includes a weak portion (1111), and the projection of the first through hole (301) on the first end plate (110) at least partially coincides with the weak portion (1111).

18. The cylindrical battery according to any one of claims 1-12, characterized in that, The pressure relief valve (111) includes a weak part (1111), and the projection of the first through hole (301) on the first end plate (110) is offset from the weak part (1111). The area of ​​the core hole (210) is 4.52 mm². 2 ≤S2≤78.5mm 2 .

19. The cylindrical battery according to any one of claims 1-12, characterized in that, The end face of the battery cell (200) includes an exposed area (202) not covered by the tab (220), and the first through hole (301) is disposed opposite to the exposed area (202).

20. The cylindrical battery according to any one of claims 1-12, characterized in that, The current collector (300) includes a first welded area (302) and a non-welded area (304). The first welded area (302) is welded to the tab (220) of the battery cell (200). The thickness of the first welded area (302) is less than the thickness of the non-welded area (304).

21. The cylindrical battery according to claim 20, characterized in that, The first through hole (301) is located in the non-welded area (304).

22. The cylindrical battery according to any one of claims 1-12, characterized in that, The melting point of the current collector (300) is less than or equal to 670°C.

23. The cylindrical battery according to any one of claims 1-12, characterized in that, The pressure relief valve (111) includes a weak part (1111). The weak portion (1111) is formed as an annular groove; or, the weak portion (1111) is formed as a discontinuous groove, and the distance between the two ends of the weak portion (1111) is 2mm-20mm.

24. The cylindrical battery according to any one of claims 1-12, characterized in that, The first end plate (110) includes a first recess (112) having a bottom wall (1121). The pressure relief valve (111) includes a weak part (1111), which is disposed on the bottom wall (1121).

25. The cylindrical battery according to any one of claims 1-12, characterized in that, The electrode portion (220) includes a positive electrode (220a) and a negative electrode (220b), the positive electrode (220a) and the negative electrode (220b) are located at the same end of the battery cell (200), and the ratio of the sum of the areas of the first through hole (301) to the area of ​​the projection of the current collector (300) on the first end plate (110) is 0.01-0.

2.

26. The cylindrical battery according to any one of claims 1-12, characterized in that, The electrode portion (220) includes a positive electrode (220a) and a negative electrode (220b), which are located at both ends of the cell (200) along the axial direction of the housing (100).

27. The cylindrical battery according to any one of claims 1-12, characterized in that, The sum of the areas S1 of the first through holes (301) is 3.14 mm. 2 -603.51mm 2 ; And / or, the area S0 of the end face of the battery cell (200) is 314 mm. 2 -3017.54 mm 2 ; Alternatively, the cross-sectional area S2 of the core hole (210) is 3.14 mm. 2 -78.5 mm 2 .

28. The cylindrical battery according to any one of claims 1-12, characterized in that, When the diameter of the cylindrical battery is greater than or equal to 40 mm and / or the axial height of the cylindrical battery is greater than or equal to 70 mm, 0.44 × 10 -3 ≤ (S1×S2) / (S0×S0) ≤ 11.25×10 -3 .

29. The cylindrical battery according to any one of claims 1-12, characterized in that, The projections of the first through hole (301) and / or the core hole (210) onto the first end plate (110) are entirely located within the area enclosed by the pressure relief valve (111).

30. The cylindrical battery according to any one of claims 1-12, characterized in that, Also includes: A pole post (410) is inserted through the first end plate (110). An insulating component (500) is disposed between the pole post (410) and the first end plate (110); The current collector (300) includes a positive current collector (300a) and a negative current collector (300b). One of the terminal post (410) and the first end plate (110) is connected to the positive current collector (300a) and the other is connected to the negative current collector (300b). The electrode (400) includes the terminal post (410) and the first end plate (110).

31. An electrical appliance, characterized in that, include: The cylindrical battery according to any one of claims 1-30.

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