Battery cell, battery and electric equipment

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell, a battery and electric equipment, the battery cell comprises a first pole piece, a second pole piece and a diaphragm, the first pole piece, the diaphragm and the second pole piece are sequentially stacked and wound to form the battery cell, the battery cell is provided with a central hole, a conductive piece is arranged in the central hole, and the conductive piece is arranged in the central hole. The conductive part corresponds to the shape of the center hole, one end of the conductive part is provided with a first end face, the first end face protrudes out of the upper end face of the battery cell, the inner ring of the battery cell, the first pole piece or the second pole piece is provided with an empty foil part, and the empty foil part is electrically connected with the conductive part; the pole pieces near the central hole can still be tightly attached after the battery cell is charged, cyclically and expanded, so that the normal embedding and separation of lithium ions are ensured, the lithium separation is improved, and the service life of the battery is prolonged; the conductive part can serve as a tab of the first pole piece or the second pole piece, so that the cost of a winding needle and the tab of the battery cell is saved.

Description

Technical Field

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

[0002] As a new type of secondary battery, lithium-ion batteries have the advantages of high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and green environmental protection. They have broad application prospects in portable appliances, power tools, large-scale energy storage, electric transportation power supply, etc.

[0003] In the prior art, after a battery undergoes multiple charging cycles, its cell will expand in volume. Because the winding design of the battery cell includes a central hole, this expansion phenomenon causes the pole pieces to squeeze each other. Specifically, the pole pieces near the central hole are subjected to pressure from the peripheral expansion portion and will shrink toward the central hole, thereby significantly increasing the gap between the pole pieces near the central hole. This increase in gap causes separation between the pole pieces that should have been tightly fitted, forming the so-called "broken bridge" phenomenon. This phenomenon hinders the normal insertion and extraction process of lithium ions between the electrodes, causing lithium plating problems, which in turn affects the life of the battery. Utility Model Content

[0004] The purpose of the utility model is to provide a battery cell, a battery and an electrical device to address the deficiencies of the prior art, thereby solving the technical problem in the prior art that after multiple charging cycles, a "broken bridge" is easily formed near the center hole of the battery cell, which hinders the normal insertion and extraction of lithium ions, causes lithium plating, and shortens the battery life.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] In the first aspect, the utility model provides a battery cell, comprising a first electrode piece, a second electrode piece and a diaphragm, wherein the first electrode piece, the diaphragm and the second electrode piece are stacked and wound in sequence to form a battery cell, wherein the battery cell has a central hole, a conductive member is arranged in the central hole, and the conductive member corresponds to the shape of the central hole, and one end of the conductive member has a first end face, and the first end face protrudes from the upper end face of the battery cell, and in the inner ring of the battery cell, the first electrode piece or the second electrode piece has a hollow foil portion, and the hollow foil portion is electrically connected to the conductive member.

[0007] Preferably, when the first pole piece, the separator and the second pole piece are stacked in sequence, along the winding direction of the battery cell, the hollow foil portion at least partially protrudes from the winding starting end of the separator.

[0008] Preferably, along the winding direction of the battery core, the number of turns of the hollow foil portion on the conductive member is 0.1 to 2 turns.

[0009] Preferably, along the height direction of the battery core, the other end of the conductive member has a second end surface, and the second end surface is flush with the edge of the lower end of the hollow foil portion.

[0010] Preferably, the second end surface is provided with an insulating layer, and the insulating layer covers the second end surface.

[0011] Preferably, the diameter of the conductive member is 0.5-3 mm.

[0012] Preferably, the conductive member is a solid structure or a hollow structure.

[0013] Preferably, the conductive member is made of aluminum, nickel, copper or copper-nickel alloy.

[0014] In a second aspect, the utility model provides a battery, comprising a shell, a top cover and the battery cell of the above-mentioned embodiment, wherein the shell has a accommodating cavity, one end of the shell has an opening, the top cover is arranged to cover the opening of the shell, the battery cell is arranged in the accommodating cavity, and the conductive member is electrically connected to the top cover or the shell through the first end face.

[0015] In a third aspect, the present invention provides an electrical device comprising the battery of the above embodiment.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0017] The battery cell of the embodiment of the present invention, through the coordinated use of the first electrode piece, the second electrode piece, the diaphragm and the conductive member, by arranging the conductive member in the center hole of the battery cell, and the conductive member corresponds to the shape of the center hole, effectively enables the conductive member to fill the center hole of the battery cell, so that the electrode piece near the center hole can be supported by the conductive member when it shrinks toward the center hole, thereby effectively making the electrode pieces near the center hole still tightly fit after the battery cell expands during the charging cycle, thereby ensuring the normal insertion and extraction of lithium ions, improving lithium plating, and extending the life of the battery. In addition, in the inner ring of the battery cell, the first electrode piece or the second electrode piece has a hollow foil portion, the hollow foil portion is electrically connected to the conductive member, one end of the conductive member has a first end face, the first end face protrudes from the upper end face of the battery cell, and the conductive member is electrically connected to the top cover or shell through the first end face, effectively enabling the conductive member to act as a tab of the first electrode piece or the second electrode piece, thereby saving the cost of the winding needle and tab of the battery cell.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 This is a schematic structural diagram of the battery of the present utility model.

[0021] Figure 2 This is a schematic diagram of the structure of the conductive part cut after winding is completed in the present invention.

[0022] Figure 3 This is a schematic diagram of the process of making the battery cell of the utility model.

[0023] Figure 4 This is a structural schematic diagram of the connection between the conductive member of the utility model and the hollow foil portion of the first pole piece.

[0024] The description of the accompanying drawings is as follows:

[0025] 100. Battery;

[0026] 10. Battery cell; 11. First pole piece; 12. Second pole piece; 13. Diaphragm; 14. Conductive member; 141. First end surface; 142. Second end surface; 15. Center hole; 16. Hollow foil portion; 17. Insulation layer;

[0027] 20. Top cover; 21. First cover; 22. Second cover; 221. Raised portion; 23. Insulating seal;

[0028] 30. Shell;

[0029] a. Winding direction of the battery cell; b. Height direction of the battery cell. DETAILED DESCRIPTION

[0030] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0031] Furthermore, the terms “first,” “second,” etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0032] In this utility model, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0033] The following will be combined with the Figures 1 to 4 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] The electrical equipment of the embodiment of the present invention includes a battery 100. The electrical equipment may be a car, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The car may be a fuel car, a gas car, or a new energy car, and the new energy car may be a pure electric car, a hybrid car, or an extended-range car, and the like; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiment of the present application does not impose any special restrictions on the above-mentioned electrical equipment.

[0035] See also Figure 1 The battery 100 of an embodiment of the present invention includes a shell 30, a top cover 20 and the battery cell 10 of the above embodiment. The shell 30 has a accommodating cavity, one end of the shell 30 has an opening, the top cover 20 is arranged to cover the opening of the shell 30, and the battery cell 10 is arranged in the accommodating cavity.

[0036] See also Figures 1 to 4The battery cell 10 of an embodiment of the present invention includes a first electrode piece 11, a second electrode piece 12 and a diaphragm 13. The first electrode piece 11, the diaphragm 13 and the second electrode piece 12 are stacked and wound in sequence to form the battery cell 10. The battery cell 10 has a central hole 15. A conductive member 14 is arranged in the central hole 15. The conductive member 14 corresponds to the shape of the central hole 15. One end of the conductive member 14 has a first end face 141. The first end face 141 protrudes from the upper end face of the battery cell 10. In the inner circle of the battery cell 10, the first electrode piece 11 or the second electrode piece 12 has a hollow foil portion 16, and the hollow foil portion 16 is electrically connected to the conductive member 14.

[0037] Compared with the prior art, the battery cell 10 of the embodiment of the present invention, through the coordinated use of the first electrode 11, the second electrode 12, the diaphragm 13 and the conductive member 14, by arranging the conductive member 14 in the center hole 15 of the battery cell 10, and the conductive member 14 corresponds to the shape of the center hole 15, effectively enables the conductive member 14 to fill the center hole 15 of the battery cell 10, so that the electrode pieces near the center hole 15 can be supported by the conductive member 14 when they shrink toward the center hole 15, thereby effectively making the electrode pieces near the center hole 15 still tightly fit after the battery cell 10 expands during the charging cycle, thereby ensuring the normal insertion and extraction of lithium ions, improving lithium plating, and extending the life of the battery 100. In addition, in the inner circle of the battery cell 10, the first pole piece 11 or the second pole piece 12 has a hollow foil portion 16, and the hollow foil portion 16 is electrically connected to the conductive member 14. One end of the conductive member 14 has a first end face 141, and the first end face 141 protrudes from the upper end face of the battery cell 10. The conductive member 14 is electrically connected to the top cover 20 or the shell 30 through the first end face 141, which effectively enables the conductive member 14 to act as the pole ear of the first pole piece 11 or the second pole piece 12, thereby saving the cost of the winding needle and pole ear of the battery cell 10.

[0038] It is understood that the polarities of the first electrode 11 and the second electrode 12 are opposite, and one of the first electrode 11 and the second electrode 12 is a positive electrode, and one of the first electrode 11 and the second electrode 12 is a negative electrode. When the first electrode 11 or the second electrode 12 is a positive electrode, the conductive member 14 is a positive electrode tab; when the first electrode 11 or the second electrode 12 is a negative electrode, the conductive member 14 is a negative electrode tab.

[0039] It is understandable that when the conductive member 14 is electrically connected to the hollow foil portion 16 , the conductive member 14 and the hollow foil portion 16 may be welded, or the conductive member 14 and the hollow foil portion 16 may be connected via a conductive adhesive.

[0040] See also Figures 2-3In some embodiments, when the first electrode sheet 11, the separator 13, and the second electrode sheet 12 are stacked in sequence, the hollow foil portion 16 at least partially protrudes from the winding starting end of the separator 13 along the winding direction a of the battery cell 10. Due to the provision of the hollow foil portion 16, when the first electrode sheet 11, the separator 13, and the second electrode sheet 12 are stacked, the hollow foil portion 16 at least partially protrudes from the winding starting end of the separator 13 along the winding direction a of the battery cell 10. This effectively enables the hollow foil portion 16 to be wound around the conductive member 14 first during winding, thereby ensuring good contact between the conductive member 14 and the hollow foil portion 16. This avoids the problem of misalignment or poor contact between the hollow foil portion 16 and the conductive member 14 that may occur during the winding process, thereby improving the overall performance and stability of the battery cell 10.

[0041] In some embodiments, along the winding direction a of the battery cell 10, the number of turns of the hollow foil portion 16 on the conductive member 14 is 0.1 to 2. By setting the number of turns of the hollow foil portion 16 on the conductive member 14, the number of turns of the hollow foil portion 16 on the conductive member 14 cannot be too many or too few. When the number of turns of the hollow foil portion 16 on the conductive member 14 is too few, that is, the number of turns of the hollow foil portion 16 on the conductive member 14 is less than 0.1, the contact area between the hollow foil portion 16 and the conductive member 14 is small, which can easily lead to poor contact between the conductive member 14 and the hollow foil portion 16, thereby affecting the electrical connection between the conductive member 14 and the hollow foil portion 16. When the number of turns of the hollow foil portion 16 on the conductive member 14 is too large, that is, the number of turns of the hollow foil portion 16 on the conductive member 14 is greater than 2, the hollow foil portion 16 will occupy part of the space of the battery cell 10, increase the weight of the battery cell 10, and thus affect the energy density of the battery 100.

[0042] Therefore, when the number of turns of the blank foil portion 16 on the conductive member 14 is 0.1 to 2, the electrical connection between the blank foil portion 16 and the conductive member 14 can be ensured while ensuring the energy density of the battery 100 .

[0043] Furthermore, the number of turns of the hollow foil portion 16 on the conductive member 14 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2. However, the present invention is not limited to the values ​​listed above, and other values ​​within the numerical range are also applicable.

[0044] In some embodiments, along the height direction b of the battery cell 10, the other end of the conductive member 14 has a second end surface 142, which is flush with the edge of the lower end of the hollow foil portion 16. The arrangement of the second end surface 142, located at the other end of the conductive member 14 and aligned with the edge of the lower end of the hollow foil portion 16, facilitates precise positioning during assembly and reduces assembly issues caused by positional deviation. Furthermore, the precise alignment of the conductive member 14 with the hollow foil portion 16 reduces the risk of short circuits caused by poor contact or misalignment, thereby improving the safety of the battery 100.

[0045] See also Figure 1 In some embodiments, the second end surface 142 is provided with an insulating layer 17, and the insulating layer 17 covers the second end surface 142. By providing the insulating layer 17, the insulating layer 17 covers the second end surface 142 of the conductive member 14, which can effectively prevent the second end surface 142 from accidentally contacting the opposite electrode and causing a short circuit in the battery cell 10.

[0046] In some embodiments, the diameter of the conductive part 14 is 0.5 to 3 mm. By setting the diameter of the conductive part 14, the diameter of the conductive part 14 cannot be too large or too small. When the diameter of the conductive part 14 is too small, that is, the diameter of the conductive part 14 is less than 0.5 mm, the conductive part 14 is thin, resulting in insufficient structural strength of the conductive part 14, and it is easy to break due to winding tension or mechanical vibration during the winding process of the battery cell 10, thereby affecting the conductive performance and safety of the battery cell 10. When the diameter of the conductive part 14 is too large, that is, the diameter of the conductive part 14 is greater than 3 mm, the conductive part 14 will occupy more space in the battery cell 10, reduce the active material content of the battery cell 10, and further affect the energy density and overall performance of the battery cell 10.

[0047] Therefore, setting the diameter of the conductive member 14 to 0.5 to 3 mm can effectively ensure the energy density of the battery 100 while guaranteeing the structural strength of the conductive member 14 and preventing the conductive member 14 from breaking during the winding process of the battery cell 10 .

[0048] Furthermore, the diameter of the conductive member 14 is 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.3 mm, 1.5 mm, 1.7 mm, 1.9 mm, 2 mm, 2.1 mm, 2.3 mm, 2.5 mm, 2.6 mm, 2.9 mm, or 3 mm, but is not limited to the values ​​listed above, and other values ​​within the numerical range are also applicable.

[0049] In some embodiments, the conductive member 14 is a solid structure or a hollow structure. When the conductive member 14 is a solid structure, the solid structure conductive member 14 has a better conductive effect, can ensure smooth current transmission, and reduce energy loss. The solid structure conductive member 14 has better structural strength, can withstand large external forces and pressures, and is not prone to deformation or breakage. When the conductive member 14 is a hollow structure, the hollow structure conductive member 14 has a lower weight than the solid structure, which can effectively reduce the weight of the battery cell 10 and increase the energy density of the battery 100.

[0050] In some embodiments, the conductive member 14 is made of aluminum, nickel, copper, or a copper-nickel alloy. When the conductive member 14 serves as a positive electrode tab, the conductive member 14 is aluminum. When the conductive member 14 serves as a negative electrode tab, the conductive member 14 is nickel, copper, or a copper-nickel alloy.

[0051] In summary, please refer to Figures 1 to 4 The method for manufacturing the battery cell 10 according to the embodiment of the present invention comprises at least the following steps:

[0052] Prepare the first pole piece 11, the second pole piece 12, the diaphragm 13 and the conductive member 14;

[0053] Align the second end surface 142 of the conductive member 14 with the edge of the lower end of the hollow foil portion 16 of the first electrode piece 11 or the second electrode piece 12, and electrically connect the conductive member 14 to the hollow foil portion 16;

[0054] The conductive member 14 is rotated, and after the hollow foil portion 16 is at least partially wound on the conductive member 14 , the diaphragm 13 and the remaining first electrode piece 11 or second electrode piece 12 are gradually inserted, and the first electrode piece 11 , the second electrode piece 12 and the diaphragm 13 are wound;

[0055] After the winding is completed, the conductive member 14 is cut off at a position where one end of the conductive member 14 is flush with the edge of the upper end of the diaphragm 13 .

[0056] It is understandable that after the conductive member 14 is cut off, the portion of the conductive member 14 located in the central hole 15 of the battery cell 10 becomes the tab of the first electrode piece 11 or the second electrode piece 12 , and the remaining portion of the conductive member 14 is used to make the next battery cell 10 .

[0057] It is understood that the cut surface of one end of the conductive member 14 at the cut position forms a first end surface 141, and the first end surface 141 is flush with the edge of the upper end of the diaphragm 13. Because the upper end of the diaphragm 13 is flattened against the upper end surface of the battery cell 10 during the manufacturing process of the battery cell 10, the first end surface 141 protrudes from the upper end surface of the battery cell 10 after the upper end of the diaphragm 13 is flattened.

[0058] See also Figure 1The top cover 20 of the embodiment of the utility model includes a first cover body 21, a second cover body 22 and an insulating seal 23. The first cover body 21 is arranged around the second cover body 22. The first cover body 21 is insulated and connected to the second cover body 22 through the insulating seal 23. The first cover body 21 is connected to the opening of the shell 30, and the conductive member 14 is electrically connected to the second cover body 22 or the shell 30 through the first end face 141.

[0059] Furthermore, when the conductive member 14 is electrically connected to the second cover 22 via the first end surface 141, a raised portion 221 is provided on the second cover 22, and the conductive member 14 is electrically connected to the raised portion 221 via the first end surface 141. This effectively ensures the connection between the second cover 22 and the conductive member 14. Furthermore, the raised portion 221 increases the thickness of the connecting region between the second cover 22 and the conductive member 14, ensuring the structural strength of this region and preventing the second cover 22 from being welded through when the conductive member 14 and the second cover 22 are welded.

[0060] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced within the present invention.

Claims

1. A battery cell, characterized in that: The invention comprises a first pole piece (11), a second pole piece (12) and a diaphragm (13); the first pole piece (11), the diaphragm (13) and the second pole piece (12) are stacked and wound in sequence to form a battery core (10); the battery core (10) has a central hole (15); a conductive member (14) is arranged in the central hole (15); the conductive member (14) corresponds to the shape of the central hole (15); one end of the conductive member (14) has a first end face (141); the first end face (141) protrudes from the upper end face of the battery core (10); in the inner circle of the battery core (10), the first pole piece (11) or the second pole piece (12) has a hollow foil portion (16); the hollow foil portion (16) is electrically connected to the conductive member (14).

2. The battery cell according to claim 1, wherein: When the first pole piece (11), the diaphragm (13) and the second pole piece (12) are stacked in sequence, along the winding direction (a) of the battery cell (10), the hollow foil portion (16) at least partially protrudes from the winding starting end of the diaphragm (13).

3. The battery cell according to claim 2, wherein: Along the winding direction (a) of the battery core (10), the number of turns of the hollow foil portion (16) on the conductive member (14) is 0.1 to 2 turns.

4. The battery cell according to claim 1, wherein: Along the height direction (b) of the battery core (10), the other end of the conductive member (14) has a second end surface (142), and the second end surface (142) is flush with the edge of the lower end of the hollow foil portion (16).

5. The battery cell according to claim 4, wherein: The second end surface (142) is provided with an insulating layer (17), and the insulating layer (17) covers the second end surface (142).

6. The battery cell according to claim 1, wherein: The diameter of the conductive member (14) is 0.5 to 3 mm.

7. The battery cell according to claim 1, wherein: The conductive member (14) is a solid structure or a hollow structure.

8. The battery cell according to claim 1, wherein: The conductive member (14) is made of aluminum, nickel, copper or a copper-nickel alloy.

9. A battery, characterized in that: The invention comprises a shell (30), a top cover (20) and a battery cell according to any one of claims 1 to 8, wherein the shell (30) has a receiving cavity, one end of the shell (30) has an opening, the top cover (20) is arranged to cover the opening of the shell (30), the battery cell (10) is arranged in the receiving cavity, and the conductive member (14) is electrically connected to the top cover (20) or the shell (30) through the first end face (141).

10. An electrical device, characterized in that: A battery comprising the battery of claim 9.

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