Cylindrical battery, battery pack and electronic device

Abstract

The utility model provides a cylindrical battery, a battery pack and an electronic device, the cylindrical battery comprises: a housing, one end of the housing in the height direction of the cylindrical battery is provided with an opening; an electrode assembly in the case and having a winding center hole; the cover plate covers the opening of the shell and is provided with an anti-explosion valve area defined by the anti-explosion valve, and the winding center hole is located in the orthographic projection range of the anti-explosion valve area of the cover plate in the height direction; wherein the winding center hole has a diameter D1, a partial region of the cover plate has a diameter D2, and 35% > = D1 / D2 > = 10%. According to the technical scheme, the safety of the cylindrical battery can be improved at least.

Description

Technical Field

[0001] The utility model relates to a cylindrical battery, a battery pack and an electronic device. Background Art

[0002] In the field of new energy power batteries, secondary batteries refer to rechargeable batteries, also known as renewable batteries or storage batteries. Unlike primary batteries, secondary batteries can undergo multiple charge and discharge cycles through reverse charging for reuse. Secondary batteries generally include electrode assemblies, shells, cover plates, etc. Secondary batteries include cylindrical batteries and square batteries. Cylindrical batteries refer to cylindrical wound core batteries, which include a shell and an electrode assembly. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet. These positive electrode sheets, negative electrode sheets, and separators are stacked on each other and wound into an electrode assembly, which is then encapsulated in a shell. At present, square batteries cannot ensure that the main body is not destroyed in the event of thermal runaway, so the safety of square batteries is not high. Cylindrical batteries have high safety characteristics. However, the safety of cylindrical batteries still needs to be improved. Utility Model Content

[0003] In view of the problems existing in the related art, the purpose of the present invention is to provide a cylindrical battery, a battery pack and an electronic device, so as to at least improve the safety of the cylindrical battery.

[0004] To achieve the above-mentioned objectives, the present invention provides a cylindrical battery, comprising: a shell having an opening at one end in the height direction of the cylindrical battery; an electrode assembly located in the shell and having a winding center hole; a cover plate covering the opening of the shell and having an explosion-proof valve area surrounded by an explosion-proof valve, wherein the winding center hole is located within the range of the orthographic projection of the explosion-proof valve area of ​​the cover plate in the height direction; wherein the winding center hole has a diameter D1, a partial area of ​​the cover plate has a diameter D2, and 35% ≥ D1 / D2 ≥ 10%.

[0005] In some embodiments, the housing has an outer diameter D3, 50%≤D2 / D3≤90%.

[0006] In some embodiments, the cylindrical battery has a height H, D2 > D1 ≥ 3% H.

[0007] In some embodiments, D3>D2≥20%H.

[0008] In some embodiments, D1 ranges from 4 mm to 8 mm.

[0009] In some embodiments, D2 ranges from 27 mm to 31 mm, and H ranges from 80 mm to 160 mm.

[0010] In some embodiments, the explosion-proof valve is a notch on the surface of the cover plate facing the electrode assembly, and H ranges from 95 mm to 120 mm.

[0011] In some embodiments, a crimping portion protruding inward is provided on the side wall of the shell adjacent to the opening, and the side wall has an inward extending curling portion on the side of the peripheral side wall facing away from the electrode assembly, and the cover plate is clamped between the crimping portion and the curling portion in the height direction.

[0012] According to an embodiment of the present application, a battery pack is also provided, which may include any of the above cylindrical batteries.

[0013] According to an embodiment of the present application, an electronic device is further provided, which may include the above-mentioned battery pack.

[0014] The beneficial technical effects of the utility model include:

[0015] The present application designs the ratio of the diameter D1 of the winding center hole to the diameter D2 corresponding to the weak part of the cover plate, so that the diameter D1 of the winding center hole can be made large enough, thereby providing a sufficiently large pressure relief channel to facilitate exhaust. When the battery suffers from thermal runaway, the pressure can be better relieved and the integrity of the battery body can be ensured, thereby improving the safety of the cylindrical battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A schematic diagram showing an electronic device according to an embodiment of the present application is a vehicle.

[0018] Figure 2 A three-dimensional view of a cylindrical battery according to an embodiment of the present application is shown.

[0019] Figure 3 A cross-sectional view of a cylindrical battery according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] In order to better understand the spirit of the embodiments of the present application, some preferred embodiments of the present application are further described below.

[0021] The embodiments of the present application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are represented by similar reference numerals. The embodiments described herein with respect to the accompanying drawings are illustrative and diagrammatic and are intended to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0022] As used herein, the terms "substantially," "substantially," "essentially," and "about" are used to describe and account for small variations, such as variations within the margin of error for manufacturing processes. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred precisely as well as instances where the event or circumstance occurred very approximately.

[0023] In this specification, unless otherwise specified or limited, relative terms such as "central", "longitudinal", "lateral", "front", "rear", "right", "left", "inner", "outer", "lower", "higher", "horizontal", "vertical", "above", "below", "above", "below", "top", "bottom" and their derivatives (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are only used for convenience of description and do not require that the present application be constructed or operated in a specific orientation.

[0024] For ease of description, “first,” “second,” “third,” etc. may be used herein to distinguish different components in a figure or a series of figures. “First,” “second,” “third,” etc. are not intended to describe the corresponding components.

[0025] The present application provides an electronic device 1000. For the convenience of description, the following embodiments are described by taking the electronic device 1000 as a vehicle as an example. Figure 1The vehicle is equipped with a battery pack 1002 inside. Battery pack 1002 can be located at the bottom, front, or rear of the vehicle body 1001. Battery pack 1002 can be used to power the vehicle, for example, as the vehicle's operating power source. The working portion of the electronic device 1000 is electrically connected to battery pack 1002 to obtain electrical energy. The vehicle can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, among others, but is not limited thereto. The working portion is the vehicle body, with battery pack 1002 located at the bottom of the vehicle body and providing electrical energy for the vehicle's operation and for the operation of its electrical components. However, in other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, or electric tool, among others. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, among others. The working portion can draw electrical energy from battery pack 1002 and perform corresponding operations, such as the blade rotation unit of a fan or the dust collection unit of a vacuum cleaner. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys; electric tools include metal cutting tools, grinding tools, assembly tools, and railway tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The present embodiment of the present application does not impose any particular limitation on the electronic device 1000.

[0026] Figure 2 1 shows a perspective view of a cylindrical battery 100 according to an embodiment of the present application, Figure 3 FIG. 1 shows a cross-sectional view of a cylindrical battery 100 according to an embodiment of the present application.

[0027] In one example of the cylindrical battery of the present invention, Figures 2 to 3As shown, the cylindrical battery 100 includes a shell 200, which includes a side wall 109 and an end wall 111 connected to one end of the side wall 109. The other end of the side wall 109 opposite to the end wall 111 is provided with an opening 205. The cover plate 220 covers the opening 205 of the shell 200 to be used to encapsulate the electrode assembly 120 and the electrolyte together with the shell 200. The material of the shell 200 can be any one of a variety of available materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The shell 200 can be cylindrical and define a accommodating cavity, and the electrode assembly 120 is arranged in the accommodating cavity. The outer diameter of the shell 200 can be determined according to the specific diameter size of the electrode assembly 120, such as 18 mm, 21 mm, 46 mm, etc. In some embodiments, the cylindrical battery 100 may be a 4680 cylindrical battery (outer diameter 46 mm, height 80 mm), or the cylindrical battery 100 may be a 4695 cylindrical battery (outer diameter 46 mm, height 95 mm), or the cylindrical battery 100 may be a 46120 cylindrical battery (outer diameter 46 mm, height 120 mm).

[0028] The electrode assembly 120 is primarily formed by stacking and winding a first electrode sheet, a second electrode sheet, and a separator positioned between the first and second electrode sheets. In some embodiments of the present application, the first electrode sheet may be a positive electrode sheet, and the second electrode sheet may be a negative electrode sheet. The wound electrode assembly 120 has a winding center hole 120c. The electrode assembly 120 has a first electrode tab 121 and a second electrode tab 122 on opposite sides of its height direction Hd. The second electrode tab 122 faces the opening 205, and the first electrode tab 121 faces the end wall 111 opposite the opening 205. The direction from the second electrode tab 122 toward the first electrode tab 121 is the height direction Hd of the electrode assembly 120. In some embodiments of the present application, the first electrode tab 121 may be a positive electrode tab, and the second electrode tab 122 may be a negative electrode tab. In some embodiments, the electrode assembly 120 may further include an insulating layer, such as insulating tape, bonded to the outer ring of the wound first electrode sheet, the second electrode sheet, and the separator.

[0029] In some embodiments, the positive electrode sheet (first electrode sheet) may include a positive electrode current collector and a positive electrode coating region, wherein the positive electrode coating region is coated on a portion of the surface of the positive electrode current collector. The positive electrode coating region is a positive electrode active material layer formed by coating the positive electrode active material. The portion of the positive electrode current collector not covered by the positive electrode coating region constitutes a positive electrode tab (first electrode tab 121). The negative electrode sheet (second electrode sheet) may include a negative electrode current collector and a negative electrode coating region, wherein the negative electrode coating region is coated on a portion of the surface of the negative electrode current collector. The negative electrode coating region is a negative electrode active material layer formed by coating the negative electrode active material. The portion of the negative electrode current collector not covered by the negative electrode coating region constitutes a negative electrode tab (second electrode tab 122).

[0030] Taking lithium-ion batteries as an example, the positive electrode current collector can be made of aluminum, and the positive electrode coating can include a positive electrode active material such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode current collector can be made of copper. The negative electrode coating can include a negative electrode active material such as carbon or silicon. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene).

[0031] An inwardly protruding crimping portion 113 (also referred to as a rolling groove) may be provided on the side wall of the housing 200 adjacent to the opening 205. The electrode assembly 120 is provided between the end wall 111 and the crimping portion 113, and the crimping portion 113 is capable of limiting the movement of the electrode assembly 120 in the height direction Hd and the opposite direction between the end wall 111 and the crimping portion 113. The end of the side wall 109 of the housing 200 on the side of the opening 205 may be configured as a crimping portion 32, which extends radially inwardly of the housing 200. The crimping portion 32 and the crimping portion 113 are spaced apart in the height direction Hd, and the crimping portion 113 and the crimping portion 32 may jointly clamp the cover plate 220. An insulating component 242 may be provided between the cover plate 220 and the housing 200 to electrically insulate the cover plate 220 from the housing 200.

[0032] The cylindrical battery 100 may further include a post 160, which passes through the end wall 111 and is insulated from the end wall 111. The post 160 may be electrically connected to the first tab 121 of the electrode assembly 120 via a first current collecting plate 301, thereby causing the post 160 to be charged, for example, positively charged. The second tab 122 may be electrically connected to the housing 200 via a second current collecting plate 302, thereby causing the housing 200 to be charged, for example, negatively charged. An insulating member 244 is provided between the post 160 and the housing 200 to electrically insulate the post 160 from the housing 200.

[0033] In an example of the cylindrical battery 100 of the present invention, the manufacturing method of the cylindrical battery 100 of the present invention includes the following steps:

[0034] Winding: The first electrode sheet, separator, and second electrode sheet are stacked and wound to form a wound structure. The uncoated portions of the positive electrode collector of the first electrode sheet and the negative electrode collector of the second electrode sheet constitute the first electrode tab 121 and the second electrode tab 122. The first electrode tab 121 and the second electrode tab 122 are bent along the radial direction of the electrode assembly 120.

[0035] The current collecting plates are welded to the electrode assembly: specifically, the first current collecting plates 301 and the second current collecting plates 302 are welded to the surface areas of the bent first electrode tab 121 and the second electrode tab 122 , respectively.

[0036] Inserting into the shell: The electrode assembly 120 welded to the first collecting plate 301 and the second collecting plate 302 is installed into the shell 200 through the opening 205. The method of installing the electrode assembly 120 in this step is not limited, for example, it can be installed manually or by a robot.

[0037] Install pole 160.

[0038] Injecting electrolyte: There is no limitation on the method of injecting the electrolyte. The electrolyte can be injected through the opening 205 or through an injection hole provided on the end wall 111. Preferably, in this embodiment, the electrolyte is injected through the opening 205, which reduces the process of providing an injection hole on the end wall 111 and allows the electrolyte to be directly injected through the existing opening 205, thereby simplifying the process and reducing costs.

[0039] Sealing: The cover plate 220 is sealed against the opening 205. Various sealing methods are available, and are not intended to be limiting. In some embodiments, the outer periphery of the housing 200 is first rolled to form a crimping portion 113 recessed toward the center of the housing 200 to restrict movement of the electrode assembly 120 in the height direction Hd. A mechanical sealing process is then used to seal the cover plate 220 to form a crimping portion 32, thereby sealing the cover plate 220 against the opening 205 of the housing 200. This step is a mature, low-cost, and highly efficient process.

[0040] Currently, prismatic batteries cannot protect their components from damage during thermal runaway, which means they cannot guarantee sufficient evacuation time for drivers and passengers in the event of an accident. Cylindrical batteries, as the earliest battery shape, offer superior safety features. The inventors of this application have discovered that the safety of cylindrical batteries can be improved by designing some unique structural proportions.

[0041] Continue to refer Figure 3 As shown, the cover plate 220 has an explosion-proof valve 350, and the portion of the cover plate 220 surrounded by the explosion-proof valve forms an explosion-proof valve area 222. In some embodiments, the explosion-proof valve 350 may have a circular ring shape in a top view. In some embodiments, the explosion-proof valve 350 is a notch on the surface of the cover plate 220 facing the electrode assembly 120. The material of the cover plate 220 can preferably be steel, or other usable metal materials. The surface of the cover plate 220 is pre-nickel-plated to prevent rust or corrosion. However, the pre-nickel plating at the notch may be damaged, so the notch is more susceptible to rust or corrosion. If the notch is set on the side of the cover plate 220 facing away from the electrode assembly 120 (i.e., facing the outside of the secondary battery), the notch will be exposed to air, thereby corroding the cover plate 220. Therefore, setting the notch on the surface of the cover plate 300 facing the electrode assembly 120 can prevent the cover plate from being corroded.

[0042] The winding center hole 120c is located within the orthographic projection of the explosion-proof valve region 222 of the cover plate 220 in the height direction Hd. Compared to other areas of the cover plate 220, the explosion-proof valve 350 is weaker and more susceptible to rupture. When the battery experiences thermal runaway, high-temperature, high-pressure emissions from the battery can break through the explosion-proof valve 350 on the cover plate 220 and be discharged to the outside of the battery through the explosion-proof valve region 222 of the cover plate 220, thereby effectively discharging the emissions. When thermal runaway causes the explosion-proof valve 350 to rupture and release pressure, a certain amount of gas thrust is required to push the explosion-proof valve region 222 of the explosion-proof valve 350 out. The winding center hole 120c serves as a pressure relief channel during battery decompression. Because the winding center hole 120c is located within the orthographic projection of the explosion-proof valve region 222, gas can provide thrust to the explosion-proof valve region 222 through the winding center hole 120c.

[0043] The diameter of the winding center hole 120c is D1. The diameter of the explosion-proof valve area 222 of the cover plate 220 surrounded by the explosion-proof valve 350 is D2. D2 can be the diameter measured at the point where the thickness of the cover plate 220 is the smallest at the explosion-proof valve 350. In some embodiments, 35% ≥ D1 / D2 ≥ 10%. This ratio design of D1 / D2 can make the proportion of the diameter D1 of the winding center hole 120c large enough, thereby providing a sufficiently large pressure relief channel to facilitate exhaust. When the battery experiences thermal runaway, it can better relieve pressure and ensure the integrity of the battery body, thereby improving the safety of the cylindrical battery 100.

[0044] The housing 200 has an outer diameter D3. In some embodiments, 50% ≤ D2 / D3 ≤ 90%. If ≤ D2 / D3 is greater than 90%, it is difficult to achieve in the processing process. Therefore, in order to ensure the processing and manufacturability of the battery, D2 / D3 ≤ 90% should be satisfied. If D2 / D3 is less than 50%, D2 may be too small, making the area of ​​the explosion-proof valve area 222 surrounded by the explosion-proof valve 350 too small, which is not conducive to pressure relief in the event of thermal runaway. By designing the D2 / D3 ratio in combination with the D1 / D2 ratio, the pressure relief channel of the cylindrical battery is optimized, which can simultaneously ensure better pressure relief and processing and manufacturability.

[0045] The height of the cylindrical battery 100 is H. Height H refers to the distance from the end wall 111 of the housing 200 to the maximum point on the opposite side of the housing 200 (in this embodiment, to the curling portion 32) in the height direction Hd, that is, the height of the housing 200 (excluding the height of the terminal 160). In some embodiments, D2>D1≥3%H. By setting the lower limit of the diameter D1 of the winding center hole 120c to 3%H and D2 being greater than D1, a winding center hole 120c with a sufficiently large diameter can be provided according to the battery height to serve as a pressure relief channel, thereby relieving pressure in the event of thermal runaway.

[0046] In some embodiments, D3>D2≥20%H. By setting the lower limit of the diameter D2 of the explosion-proof valve region 222 to 20%H and D3 being greater than D2, an area of ​​the explosion-proof valve region 222 having a sufficiently large diameter can be provided according to the battery height. This allows the explosion-proof valve region 222 to be more easily pushed out when thermal runaway occurs in the battery, thereby providing better pressure relief.

[0047] In some embodiments, the diameter D1 of the winding center hole 120c ranges from 4 mm to 8 mm. This value range of D1 can provide a sufficiently large winding center hole 120c for various types of cylindrical batteries to serve as a pressure relief channel to relieve pressure when the battery experiences thermal runaway.

[0048] In some embodiments, the diameter D2 of the explosion-proof valve region 222 ranges from 27 mm to 31 mm. In embodiments where the cover plate 220 is clamped by the crimping portion 113 and the crimping portion 32, this range of D2 represents the maximum achievable diameter range based on the configuration of the crimping portion 113 and the crimping portion 32.

[0049] The technical solution of the present application can match a variety of cylindrical batteries. In some embodiments, the cylindrical battery 100 is a 46 series cylindrical battery, that is, the outer diameter D3 of the shell 200 is 46 mm, such as the above-mentioned 4680, 4695, and 46120 cylindrical batteries. In some embodiments, the height H of the cylindrical battery 100 ranges from 80 mm to 160 mm. For example, the height H can be 120 mm, 95 mm, or 80 mm. The technical solution of the present application can provide a sufficiently large pressure relief channel for a variety of cylindrical batteries. When the battery has thermal runaway, the pressure can be better relieved, thereby improving the safety of the cylindrical battery 100, for example, when the height H is 120 mm.

[0050] In some embodiments, the height H can be in the range of 95 mm to 120 mm. Within this height range, a more suitable diameter D2 of the explosion-proof valve region 222 can be matched to a range of 27 mm to 31 mm, and the diameter D1 can be increased accordingly. As described above, this helps to relieve pressure and ensure the safety of the cylindrical battery 100.

[0051] The embodiment of the present application also provides a battery pack 1002 (see Figure 1 ), including any one of the cylindrical batteries 100 described above, and the battery pack 1002 can have the beneficial effects described above with respect to the cylindrical battery 100.

[0052] The embodiment of the present application also provides an electronic device 1000 (see Figure 1 ), including the above-mentioned battery pack 1002, and the electronic device 1000 can have the beneficial effects described above with respect to the cylindrical battery 100 and / or the battery pack 1002.

[0053] In some embodiments, the electronic device 1000 is a vehicle, such as Figure 1 As shown above. Figure 3 As described, the cylindrical battery 100 provided in the embodiment of the present application can ensure that the battery body is not damaged when the battery undergoes thermal runaway, thereby ensuring that sufficient time is left for the driver and passengers to evacuate when a safety accident occurs.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A cylindrical battery, characterized in that: include: a housing having an opening at one end in a height direction of the cylindrical battery; an electrode assembly located in the housing and having a winding center hole; a cover plate, covering the opening of the housing and having an explosion-proof valve area surrounded by an explosion-proof valve, wherein the winding center hole is located within the orthographic projection range of the explosion-proof valve area of ​​the cover plate in the height direction; The winding center hole has a diameter D1, the explosion-proof valve area of ​​the cover plate has a diameter D2, and 35%≥D1 / D2≥10%.

2. The cylindrical battery according to claim 1, characterized in that: The housing has an outer diameter D3, 50%≤D2 / D3≤90%.

3. The cylindrical battery according to claim 1, characterized in that: The cylindrical battery has a height H, D2>D1≥3%H.

4. The cylindrical battery according to claim 2, characterized in that: The cylindrical battery has a height H, D3>D2≥20%H.

5. The cylindrical battery according to claim 1, characterized in that: The range of D1 is 4mm-8mm.

6. The cylindrical battery according to claim 3 or 4, characterized in that: The range of D2 is 27mm-31mm, The range of H is 80mm-160mm.

7. The cylindrical battery according to claim 1, characterized in that: The explosion-proof valve is a notch on the surface of the cover plate facing the electrode assembly; The range of H is 95mm-120mm.

8. The cylindrical battery according to claim 1, characterized in that: A crimping portion protruding inward is provided at the side wall of the shell adjacent to the opening, and the side wall has a curling portion extending inward on the side of the crimping portion facing away from the electrode assembly, and the cover plate is clamped between the crimping portion and the curling portion in the height direction.

9. A battery pack, characterized in that: The cylindrical battery comprises the cylindrical battery according to any one of claims 1 to 8.

10. An electronic device, characterized in that: Comprising the battery pack as claimed in claim 9.

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