CN212967961U

CN212967961U - Button cell

Info

Publication number: CN212967961U
Application number: CN202020978215.1U
Authority: CN
Inventors: 黄凯; 辛汉帅; 欧阳巍
Original assignee: Zhuhai Weiju Industrial Co ltd
Current assignee: Zhuhai Juneng New Energy Co ltd
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2021-04-13
Anticipated expiration: 2030-06-01

Abstract

The utility model relates to a button cell, which comprises a shell and an electric core arranged in the shell, wherein the electric core comprises at least one positive plate, at least one negative plate and at least one isolating plate arranged between the at least one positive plate and the at least one negative plate; at least one of the at least one positive plate and the at least one negative plate comprises a current collector, and a polymer PTC layer and an active substance layer which are sequentially arranged on at least one surface of the current collector, wherein the active substance layer comprises an electrode active substance, and the polymer PTC layer comprises a polymer matrix, and conductive particles embedded in the polymer matrix and the electrode active substance. The polymer PTC layer can reversibly change the resistivity of the battery core, and when the temperature of the battery is raised due to a local short circuit, the internal resistance of the battery can be improved, so that the short-circuit current is reduced, and the safety of the battery is improved; the polymer matrix is filled with a certain proportion of electrode active substances, which is beneficial to increasing the capacity of the button cell.

Description

Button cell

Technical Field

The utility model relates to a battery technology field, more specifically say, relate to a button cell.

Background

Button cells are small and high energy density cells that are widely used in various areas of life, particularly in small portable electronic devices such as electronic watches, bluetooth headsets, hearing aids, and the like. The capacity of the button cell is one of the important indexes of the button cell.

When the button cell is subjected to mechanical damage, liquid leakage and the like, dangerous short circuit and exothermic reaction can occur, so that the internal pressure and temperature of the cell are increased, and the cell is burnt and even has explosion accidents. Therefore, how to improve the safety of the button cell and ensure the battery capacity becomes a main technical problem faced by the button cell.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in that, to the above-mentioned defect of prior art, a modified button cell is provided.

The utility model provides a technical scheme that its technical problem adopted is: constructing a button battery, which comprises a shell and a battery cell arranged in the shell, wherein the battery cell comprises at least one positive pole piece, at least one negative pole piece and at least one isolating piece arranged between the at least one positive pole piece and the at least one negative pole piece; at least one of the at least one positive plate and the at least one negative plate comprises a current collector, and a polymer PTC layer and an active substance layer which are sequentially arranged on at least one surface of the current collector, wherein the active substance layer comprises an electrode active substance, and the polymer PTC layer comprises a polymer matrix, and conductive particles embedded in the polymer matrix and the electrode active substance.

In some embodiments, the cell is made by stacking or winding the at least one positive electrode tab, the at least one negative electrode tab, and the at least one separator tab.

In some embodiments, the polymeric PTC layer and the active material layer are coated on both opposing surfaces of the current collector.

In some embodiments, the current collector has a thickness of 2 to 15 μm, the polymer PTC layer has a thickness of 1 to 10 μm, and the active material layer has a thickness of 50 to 200 μm.

In some embodiments, the housing is provided with at least one lead-out hole, the button cell further comprises at least one conductor arranged in the at least one lead-out hole and at least one insulating seal arranged between the at least one lead-out hole and the at least one conductor and used for isolating the at least one conductor from the housing, and the at least one conductor is electrically connected with the at least one positive pole piece or the at least one negative pole piece.

In some embodiments, two ends of the insulating sealing body respectively extend out of the leading-out hole, and the cross-sectional dimensions of the two ends of the insulating sealing body are respectively larger than the cross-sectional dimension of the leading-out hole.

In some embodiments, the housing includes a wall portion and at least one protrusion protruding from a surface of the wall portion toward or away from the cell, and the at least one lead-out hole penetrates the wall portion and the at least one protrusion in a longitudinal direction.

In some embodiments, the housing includes a lower case having an opening at the top and a mating upper case, the wall portion is formed on the upper case, and the peripheral edge of the wall portion is hermetically joined to the opening edge of the lower case by laser welding.

In some embodiments, the upper case and the lower case are made of a metal conductive material, the upper case is electrically connected to one of the at least one positive electrode tab and the at least one negative electrode tab, and the at least one conductor is electrically connected to the other of the at least one positive electrode tab and the at least one negative electrode tab.

In some embodiments, the button cell comprises at least two electrical conductors and at least two insulating seals, wherein the at least two electrical conductors are electrically connected with the at least one positive plate and the at least one negative plate respectively.

Implement the utility model discloses following beneficial effect has at least: in the button battery of the utility model, the polymer PTC layer can reversibly change the resistivity of the battery cell, thereby reducing the local over-current or overheating in the battery; when the battery is short-circuited and heated, the internal resistance of the battery is improved, so that the short-circuit current is reduced, and the safety performance of the battery is improved; the polymer matrix is filled with a certain proportion of electrode active substances, which is beneficial to increasing the capacity of the button cell.

Drawings

The invention will be further explained with reference to the drawings and examples, wherein:

fig. 1 is a schematic cross-sectional view of a button cell in a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a positive plate of the button cell shown in FIG. 1;

fig. 3 is a schematic cross-sectional view of a button cell in a second embodiment of the present invention.

Detailed Description

In order to clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1-2, a button cell in a first embodiment of the present invention includes a sealed housing 1 and a cell 2 disposed in the housing 1. The battery core 2 includes at least one positive electrode tab 21, at least one negative electrode tab 22, and at least one spacer 23 disposed between the at least one positive electrode tab 21 and the at least one negative electrode tab 22. The core 2 can be made in the form of spiral winding or in the form of lamination.

The positive electrode sheet 21 may include a positive electrode collector 211 and positive electrode active material layers 213 coated on opposite surfaces of the positive electrode collector 211 in some embodiments. The positive electrode collector 211 may be a conductive metal foil such as an aluminum foil, and the positive electrode active material layer 213 may include a positive electrode active material, a conductive agent (e.g., acetylene black), and a binder (e.g., PVDF). In the case of a lithium ion battery, the positive electrode active material may be a semiconductor material such as lithium cobaltate.

In some embodiments, the positive electrode sheet 21 may further include a positive electrode polymer PTC layer 212 disposed between the positive electrode collector 211 and the positive electrode active material layer 213. The positive electrode polymer PTC layer 212 may include a polymer matrix and conductive particles filled in the polymer matrix. The conductive particles may be carbon black, graphite, or metal oxide, etc., which may provide excellent conductivity to the positive electrode polymer PTC layer 212. By coating the positive electrode current collector 211 with the positive electrode conductive polymer PTC layer 212 with Positive Temperature Coefficient (PTC), when the battery is short-circuited and heated, the internal resistance of the battery is improved, so that the short-circuit current is reduced, and the safety performance of the battery is improved; in addition, the coating mode enables the battery core to have higher temperature sensitivity, and can also ensure that the battery has higher safety when the battery core is locally short-circuited or heated. Furthermore, the polymer matrix can be filled with a certain proportion of positive active substances, and the positive active substances can provide a space for lithium ions and are beneficial to increasing the capacity of the button cell. The positive electrode active material mixed into the positive electrode polymer PTC layer 212 may be generally the same as the positive electrode active material in the positive electrode active material layer 213, and may be, for example, lithium cobaltate.

The negative electrode sheet 22 may include a negative electrode collector and a negative electrode active material layer coated on opposite surfaces of the negative electrode collector in some embodiments. The negative electrode current collector may be a conductive metal foil such as a copper foil, and the negative electrode active material layer may include a negative electrode active material (e.g., a conductive material such as graphite), a conductive agent (e.g., acetylene black), a thickener (e.g., CMC), and a binder (e.g., SBR). Similarly to the structure of the positive electrode sheet 21, a negative polymer PTC layer may be provided between the negative current collector and the negative active material layer. The negative electrode active material mixed in the negative electrode polymer PTC layer may be generally the same as the negative electrode active material in the negative electrode active material layer, and may be, for example, graphite. It is to be understood that in other embodiments, the polymeric PTC layer and the active material layer may be coated on only one surface of the current collector.

In some embodiments, the current collector may have a thickness of 2-15 μm, for example around 10 μm; the thickness of the polymeric PTC layer may be 1-10 μm; the thickness of the active material layer may be 50 to 200 μm, for example, about 100 μm.

In the embodiment shown in fig. 1, the cell 2 takes the form of a spiral winding, and the axis thereof coincides with the central axis of the housing 1. The battery cell 2 may further include an accommodating space 24 in some embodiments, and a central axis of the accommodating space 24 may coincide with a central axis of the battery cell 2. After the winding of the electric core 2 is completed, the winding core is drawn out to form an axial cavity, and the axial cavity forms an accommodating space 24.

The housing 1 is electrically conductive and electrically connectable to the positive electrode tab 21. The housing 1 may further have a lead-out hole 112, and the conductive body 4 and the insulating sealing body 3 are disposed in the lead-out hole 112 along the longitudinal direction. The conductor 4 is electrically connected to the negative electrode sheet 22, and the insulating seal body 3 is provided between the wall of the lead-out hole 112 and the conductor 4 to insulate and isolate the conductor 4 from the case 1. It is understood that in other embodiments, the negative electrode tab 22 may be electrically connected to the housing 1, and the positive electrode tab 21 may be electrically connected to the conductor 4. The number of the lead-out holes 112, the insulating sealing body 3, and the electric conductor 4 is not limited to one, and two or more may be applied.

The housing 1 may be substantially in the shape of an oblate cylinder in some embodiments, that is, the outer diameter of the button cell is larger than the height of the button cell, the thickness of the housing 1 may be 0.1-1mm, and the outer diameter of the housing 1 (the outer diameter of the button cell) may be more than 6 mm. The housing 1 may include a cylindrical lower case 12 having an opening at the top and an upper case 11 matched thereto. The upper case 11 may include a flat plate-shaped wall portion 111 and a protruding portion 113 extending from the wall portion 111 toward the battery cell 2, and the lead-out hole 112 penetrates the wall portion 111 and the protruding portion 113 in the longitudinal direction. Both the lower case 12 and the upper case 11 may be made of a metal conductive material, such as stainless steel, aluminum, iron, or other laser weldable material. The peripheral edge of the wall portion 111 may be hermetically joined to the opening edge of the lower case 12 by laser welding, and the protruding portion 113 may be formed by stretch-molding the wall portion 111 toward the side facing the battery cell 2.

In the present embodiment, the protruding portion 113 and the leading-out hole 112 are located at the middle position of the wall portion 111, and the central axis thereof may coincide with the central axis of the battery cell 2.The protruding part 113 is located in the accommodating space 24, which can improve the space utilization rate of the button cell. In other embodiments, the protruding portion 113 and the lead-out hole 112 may also be located at other positions of the wall portion 111, for example, near the periphery of the wall portion 111, and the central axes of the protruding portion 113 and the lead-out hole 112 may also be parallel to the central axis of the housing 1 or inclined at a certain angle, which may be designed according to actual requirements. Typically, the angle between the protrusion 113 and the wall 111 may be 30 degrees⁰-150⁰. The diameter of the extraction hole 112 may be 4mm or less. Preferably, the diameter of the lead-out hole 112 may be approximately 5% -35% of the outer diameter of the housing 1.

The insulating sealing body 3 is hermetically plugged in the lead-out hole 112 and can be made of flexible insulating materials such as silica gel and rubber. The insulating seal 3 may in some embodiments include a first end 31 at an upper portion, a second end 33 at a lower portion, and a body portion 32 between the first end 31 and the second end 33. The main body 32 is disposed in the lead-out hole 112, and the outer diameter of the main body 32 may be slightly larger than the aperture of the lead-out hole 112, so that the insulating sealing body 3 and the lead-out hole 112 are in interference fit, the sealing performance is better, and the insulating sealing body 3 may be fixed by the interference fit. The first end 31 and the second end 33 are exposed outside the lead-out hole 112, and the outer diameters thereof are larger than the outer diameter of the body portion 32. The lower end surface of the first end 31 abuts against the upper end surface of the wall portion 111, and the upper end surface of the second end 33 abuts against the lower end surface of the protrusion 113, so that the insulating sealing body 3 is clamped and fixed, and the insulating sealing body 3 is prevented from being removed from the lead-out hole 112. The insulating seal 3 can be inserted into the lead-out hole 112 through the second end 33. to facilitate insertion of the insulating seal 3, the second end 33 can have a pointed guide structure that facilitates insertion, for example, the second end 33 can be conical.

In addition, because the cohesion between insulating seal 3 and the epitheca 11 has certain intensity value, after battery internal pressure exceeded this intensity value, insulating seal 3 and epitheca 11 can break away, realize opening the pressure release to furthest reduces battery safety hazard degree, improves battery security.

The electric conductor 4 is longitudinally inserted into the insulating sealing body 3, and both ends thereof are exposed from both ends of the insulating sealing body 3, respectively. The conductor 4 can be made of rigid conductive material to enhance the pressure resistance; alternatively, the conductive body 4 may be made of a flexible conductive material, so that the conductive body 4 can be directly connected to an electronic component such as a circuit board or a load without an additional soldering lead. The conductor 4 may be longitudinally inserted into the receiving space 24, the lower end of the conductor 4 may extend to near the bottom of the receiving space 24 to be connected to the lower end of the negative electrode 22, and the lower end of the conductor 4 may be spaced apart from the bottom wall of the lower case 12 to be insulated from the lower case 12.

The upper case 11 may further be provided with a liquid injection hole 115 for injecting an electrolyte into the outer case 1. The button cell can also comprise a blocking piece 5 for blocking the liquid injection hole 115 after the liquid injection is finished.

When the button cell is manufactured, the following steps can be adopted:

s1, providing a lower shell 12 and a battery cell 2, and disposing the battery cell 2 in the lower shell 12;

s2, providing the upper shell 11 with the wall part 111, the projection 113, the drawing hole 112 and the liquid injection hole 115;

s3, providing the insulating sealing body 3 and the electric conductor 4, inserting the second end 33 of the insulating sealing body 3 into the lead-out hole 112, and penetrating the electric conductor 4 through the insulating sealing body 3;

s4, laser welding the peripheral edge of wall 111 to lower case 12 to form housing 1;

and S5, injecting the electrolyte into the shell 1 through the injection hole 115, and plugging the plugging piece 5 to plug and seal the injection hole 115 after the injection is finished.

Fig. 3 shows a button cell in a second embodiment of the present invention, which is different from the first embodiment in that: the button battery comprises two electric conductors 4 and two insulating sealing bodies 3, wherein the two electric conductors 4 are respectively and electrically connected with a positive plate 21 and a negative plate 22 of an electric core 2; further, the protruding portion 113 protrudes from the wall portion 111 in a direction away from the battery cell 2. It is to be understood that the number of the insulating sealing body 3 and the conductor 4 is not limited to two, and two or more may be applied.

In particular, in the present embodiment, the lower case 12 and the upper case 11 of the button cell can be made of a conductive or non-conductive material. The upper case 11 may include a wall portion 111, two protruding portions 113 formed by extending surfaces of the wall portion 111 away from the battery cell 2, and two lead-out holes 112 respectively penetrating the two protruding portions 113 and the wall portion 111. The two protruding portions 113 may be respectively located near the periphery of the wall portion 111, and further, the two protruding portions 113 may be respectively symmetrically disposed at two opposite sides of the wall portion 111. In other embodiments, the two protrusions 113 may be located at other positions of the wall portion 111, for example, one of the protrusions 113 is located near the periphery of the wall portion 111, and the other is located at the middle of the wall portion 111. In other embodiments, the two protruding parts 113 may also be respectively disposed on different sides of the housing 1, i.e., the two protruding parts 113 may also be respectively formed on the upper shell 11 and the lower shell 12.

The end of the protrusion 113 facing away from the wall 111 may be provided with an inwardly extending pressing portion 114 to lockingly secure the insulating sealing body 3. The protruding portion 113 may be in a vertical cylindrical shape, the pressing portion 114 may be in a circular truncated cone shape, and an included angle between the pressing portion 114 and the protruding portion 113 may be an obtuse angle, i.e., 90 degrees⁰<α<180⁰. Preferably, the included angle α between the pressing portion 114 and the protrusion 113 may be 120⁰-160⁰Within the range, the good locking effect can be ensured.

The lead-out hole 112 penetrates the wall 111, the protrusion 113 and the pressing part 114 in sequence along the longitudinal direction, and the insulating sealing body 3 is hermetically plugged in the lead-out hole 112 along the longitudinal direction and is in interference fit with the lead-out hole 112. Both ends of the insulating sealing body 3 can be extended out of the lead-out holes 112, respectively. Because the outer diameter of the insulating sealing body 3 is larger than the aperture of the leading-out hole 112, the part of the insulating sealing body 3 positioned in the leading-out hole 112 is extruded and contracted, and the parts of the two ends of the insulating sealing body 3 extending out of the leading-out hole 112 are expanded and reset, so that the sizes of the extending parts of the two ends are larger than the size of the leading-out hole 112, and the sealing effect and the locking effect are further improved. In addition, one end of the insulating sealing body 3 corresponding to the extruding part 114 extends out of the extruding part 114, so that the extruding part 114 can be embedded into the insulating sealing body 3, and the locking effect is better. The end of the insulating sealing body 3 opposite to the battery cell 2 extends out of the wall part 111, and has a certain gap with the battery cell 2, so as to provide a space for temperature deformation of the battery cell 2, and also avoid short circuit caused by contact between the battery cell 2 and the upper shell 11, and the safety is higher.

The lower case 12 and the upper case 11 may be made of a metal material that can be welded by laser, such as stainless steel, aluminum, iron, and the like, in this case, the protruding portion 113 may be formed by stretching the wall portion 111 to a side away from the electric core 2, and the pressing portion 114 may be formed by inwardly spinning an end of the protruding portion 113 away from the wall portion 111, which is convenient for manufacturing. After the pressing portion 114 is spun inward, the insulating sealing body 3 is pressed to be elastically deformed, so that the insulating sealing body 3 is more firmly locked and fixed in the leading-out hole 112, and is prevented from falling off. The locking and fixing mode has the advantages of simple structure, reliable locking, simple process and manufacture and the like, and an additional fixing piece is not required to be arranged to fix the insulating sealing body 3, so that the space utilization rate of the button cell is improved. In other embodiments, the lower case 12 and the upper case 11 may be made of laser-weldable plastic such as Peek, and the pressing portion 114, the protruding portion 113, and the wall portion 111 may be integrally injection-molded.

The lead-out hole 112 can also be used for injecting electrolyte into the shell 1, and after the electrolyte injection is completed through the lead-out hole 112, the insulating sealing body 3 is plugged in for sealing, so that the electrolyte injection hole does not need to be additionally formed. In another embodiment, a single liquid injection hole may be formed in the wall 111 for injecting the electrolyte into the casing 1. The button cell can also comprise a plugging piece for plugging the liquid injection hole after the liquid injection is finished.

When this external circuit board of button cell, can correspond protruding portion 113 on the circuit board and seted up and dodge the hole, peg graft each other with protruding portion 113 through this dodging the hole to effectively combine with the circuit board space, promote electric core energy density, in addition, still can be convenient for the installation and the location of circuit board.

When the button cell is manufactured, the following steps can be adopted:

s2, providing the upper case 11 formed with the wall portion 111, the protruding portion 113, and the lead-out hole 112;

s3, laser welding the peripheral edge of wall 111 to lower case 12 to form housing 1;

s4, injecting an electrolyte into the case 1 through the lead-out hole 112;

s5, providing the insulating sealing body 3 and the electric conductor 4, plugging the insulating sealing body 3 into the lead-out hole 112, and penetrating the electric conductor 4 through the insulating sealing body 3;

s6, the end of the protruding part 113 away from the wall part 111 is spun inward to form a pressing part 114 to lock the insulating sealing body 3.

It is to be understood that the above-described respective technical features may be used in any combination without limitation.

The above examples only represent the preferred embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention; it should be noted that, for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention; therefore, all changes and modifications that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A button battery comprises a shell (1) and a battery cell (2) arranged in the shell (1), wherein the battery cell (2) comprises at least one positive pole piece (21), at least one negative pole piece (22) and at least one isolating piece (23) arranged between the at least one positive pole piece (21) and the at least one negative pole piece (22); characterized in that at least one of the at least one positive electrode tab (21) and the at least one negative electrode tab (22) comprises a current collector and a polymer PTC layer and an active material layer sequentially disposed on at least one surface of the current collector, the active material layer comprises an electrode active material, and the polymer PTC layer comprises a polymer matrix and conductive particles and the electrode active material embedded in the polymer matrix.

2. Button cell according to claim 1, characterized in that the electrical core (2) is made by laminating or winding the at least one positive plate (21), the at least one negative plate (22) and the at least one separator plate (23).

3. The button cell according to claim 1, wherein the current collector is coated with the polymeric PTC layer and the active material layer on both opposing surfaces.

4. The button cell according to claim 1, wherein the current collector has a thickness of 2-15 μm, the polymer PTC layer has a thickness of 1-10 μm, and the active material layer has a thickness of 50-200 μm.

5. The button cell according to any one of claims 1 to 4, characterized in that at least one lead-out hole (112) is provided on the housing (1), the button cell further comprises at least one conductor (4) disposed in the at least one lead-out hole (112) and at least one insulating seal (3) disposed between the at least one lead-out hole (112) and the at least one conductor (4) for isolating the at least one conductor (4) from the housing (1), and the at least one conductor (4) is electrically connected to the at least one positive electrode plate (21) or the at least one negative electrode plate (22).

6. The button cell according to claim 5, characterized in that both ends of the insulating sealing body (3) respectively extend out of the lead-out hole (112), and the cross-sectional dimensions of both ends of the insulating sealing body (3) are respectively larger than the cross-sectional dimensions of the lead-out hole (112).

7. Button cell according to claim 5, wherein the housing (1) comprises a wall (111) and at least one protrusion (113) protruding from a surface of the wall (111) towards or away from the cell (2), the at least one lead-out opening (112) extending through the wall (111) and the at least one protrusion (113) in the longitudinal direction.

8. The button cell according to claim 7, wherein the outer case (1) comprises a lower case (12) having an opening at the top and a mating upper case (11), the wall portion (111) is formed on the upper case (11), and the periphery of the wall portion (111) is hermetically bonded to the opening edge of the lower case (12) by laser welding.

9. The button cell according to claim 8, wherein the upper case (11) and the lower case (12) are made of a metal conductive material, the upper case (11) is electrically connected to one of the at least one positive electrode plate (21) and the at least one negative electrode plate (22), and the at least one conductor (4) is electrically connected to the other of the at least one positive electrode plate (21) and the at least one negative electrode plate (22).

10. The button cell according to claim 5, characterized in that it comprises at least two electrical conductors (4) and at least two insulation seals (3), at least two electrical conductors (4) being electrically connected to the at least one positive electrode tab (21) and the at least one negative electrode tab (22), respectively.