CN212967848U

CN212967848U - Button cell

Info

Publication number: CN212967848U
Application number: CN202020978163.8U
Authority: CN
Inventors: 辛汉帅; 黄凯; 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; the button cell further comprises at least one sealing element arranged in the at least one through hole and at least one low-temperature tin for hermetically fixing the at least one sealing element in the at least one through hole. When the battery is short-circuited and heated, the temperature and the pressure inside the battery are increased, when the temperature is increased to the melting point of the low-temperature tin, the low-temperature tin is melted, the sealing element is ejected out under the action of the pressure inside the battery, the pressure relief is realized, and the safety performance of the battery is improved.

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.

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 becomes a major technical problem for the button cell.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in, to the above-mentioned defect of prior art, provide a modified button cell, this button cell can open the pressure release when taking place the short circuit intensification, improves the battery security.

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; the button cell further comprises at least one sealing element arranged in the at least one through hole and at least one low-temperature tin for hermetically fixing the at least one sealing element in the at least one through hole.

In some embodiments, the periphery of the outer surface of the sealing member includes an arc surface or a slope surface, so that a filling space is formed between the periphery of the outer surface of the sealing member and the wall of the through hole, and the low temperature tin is deposited on the outer surface of the sealing member and filled in the filling space.

In some embodiments, the seal is spherical and the seal has an interference of 0-20% with respect to the through hole.

In some embodiments, the button cell is a lithium ion cell, and the melting point of the low temperature tin is 100-200 ℃.

In some embodiments, the wall portion is further provided with at least one lead-out hole, the button cell further comprises at least one conductor penetrating the at least one lead-out hole and at least one insulating sealing body 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 one of the at least one positive pole piece and the at least one negative pole piece.

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 includes the wall portion and at least one protrusion protruding from a surface of the wall portion toward or away from the battery cell, and the at least one lead-out hole longitudinally penetrates through the wall portion and the at least one protrusion.

In some embodiments, the insulating seal includes a first end, a second end, and a body portion between the first end and the second end, the body portion being interference fit in the exit aperture, the first end and the second end both being exposed outside the exit aperture.

In some embodiments, the wall portion is electrically conductive, and the wall portion 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 insulation 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: when the button cell is short-circuited and heated, the temperature and the pressure inside the cell are raised, when the temperature is raised to the melting point of the low-temperature tin, the low-temperature tin is melted, the sealing element is ejected out under the action of the pressure inside the cell, the pressure relief is realized, and the safety performance of the cell is improved.

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 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.

Fig. 1 shows a button cell according to a first embodiment of the present invention, which may be a solid-state battery, a semi-solid-state battery, or a liquid-state battery, and may include a sealed housing 1 and a battery cell 2 disposed in the housing 1.

The battery cell 2 comprises at least one positive electrode sheet 21, at least one negative electrode sheet 22 and at least one separator sheet 23 arranged between the at least one positive electrode sheet 21 and the at least one negative electrode sheet 22. The positive electrode sheet 21 may include a positive electrode collector and a positive electrode active material layer coated on at least one surface of the positive electrode collector. In some embodiments, the positive electrode current collector may be a conductive metal foil such as an aluminum foil, and the positive electrode active material layer may include a positive electrode active material, a conductive agent, and a binder. Taking a lithium ion battery as an example, the positive electrode active material may be a semiconductor material such as lithium cobaltate, the conductive agent may be acetylene black, and the binder may be PVDF. The negative electrode sheet 22 may include a negative electrode collector and a negative electrode active material layer coated on 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 layer (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).

The core 2 can be made in the form of spiral winding or in the form of lamination. In the present embodiment, the battery cell 2 is made in the form of a spiral winding, and the central 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. After the at least one positive plate 21, the at least one negative plate 22 and the at least one spacer 23 are wound around a winding core, the winding core is pulled out, an axial cavity with a central axis coinciding with that of the electric core 2 is formed, and the axial cavity forms an accommodating space 24.

The housing 1 may be substantially in the form of an oblate cylinder, i.e. the outer diameter of the housing 1 is larger than its height. The thickness of the shell 1 can be 0.1-1mm, and the outer diameter of the shell 1 (the outer diameter of the button cell) can 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. In some embodiments, the upper case 11 is provided with a through hole 115, and the button cell further includes a sealing member 5 provided in the through hole 115 and low temperature tin 6 for sealingly fixing the sealing member 5 in the through hole 115. The melting point of the low-temperature tin 6 is less than the autoignition temperature of the button cell, for example, for a lithium ion battery, the melting point of the low-temperature tin 6 may be 100-200 ℃. When button cell took place the short circuit and heaied up, the inside temperature of battery and pressure all can rise, and after the temperature rose to low temperature tin 6's melting point, low temperature tin 6 can melt, and sealing member 5 can be ejecting under the effect of battery internal pressure, realizes opening the pressure release to furthest reduces battery safety hazard degree, improves battery security. It is understood that in other embodiments, the through hole 115 and the sealing member 5 may be disposed on the lower shell 12; the number of the through holes 115 and the sealing members 5 is not limited to one, and two or more may be used.

The sealing element 5 can be made of metal materials such as steel, copper, aluminum and the like; alternatively, the sealing member 5 may be made of plastic, rubber, thermoplastic elastomer TPE/TPR, etc. In some embodiments, the periphery of the outer surface (the side facing away from the battery cell 2) of the sealing member 5 is a slope or a cambered surface, so that a filling space is formed between the periphery and the wall of the through hole 115, and thus the low-temperature tin 6 can be filled into the filling space during welding, and the bonding force between the sealing member 5 and the through hole 115 is improved. In the present embodiment, the sealing member 5 is spherical, and the diameter of the sealing member 5 may be 0.5-2 mm. The diameter of the sealing member 5 is equivalent to the hole diameter of the through hole 115, for example, the diameter of the sealing member 5 may be equal to or slightly larger than the hole diameter of the through hole 115. Typically, the sealing member 5 may be interfered with 0 to 20% with respect to the through-hole 115, i.e., the original size of the sealing member 5 (the size when not inserted into the through-hole 115) is 1 to 1.2 times the hole diameter of the through-hole 115. The spherical seal member 5 is such that the seal member 5 has an upper surface (outer surface) in the shape of a circular arc, and the low-temperature tin 6 is weld-deposited on the upper surface of the seal member 5.

In the present embodiment, the housing 1 is electrically conductive and can be electrically connected 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 hole wall of the lead-out hole 112 and the outer wall of the conductor 4, and insulates and separates 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 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. The through hole 115 penetrates the wall portion 111 in the longitudinal direction, 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. It is understood that in other embodiments, the through hole 115 and the lead-out hole 112 may be disposed on different sides of the housing 1.

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 protrusion 113 and the lead-out hole 112 may be located at other positions of the wall 111, for example, near the periphery of the wall 111, and the central axes of the protrusion 113 and the lead-out hole 112 may be parallel to or inclined with a certain included angle with the central axis of the housing 1The inclined arrangement can be designed according to actual requirements. Typically, the angle between the protrusion 113 and the wall 111 may be 30 degrees⁰-150⁰. The aperture of the extraction hole 112 may be 4mm or less, and in some embodiments, the aperture of the extraction hole 112 may be larger than the aperture of the through hole 115. 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 sealing element 5 and the insulating sealing body 3 can be opened for pressure relief at the same time or can be opened for pressure relief successively, for example, when the temperature in the battery is raised to melt the low-temperature tin 6, the sealing element 5 is opened for pressure relief, so that the internal pressure of the battery is reduced; if accident or battery internal pressure sharply increase, sealing member 5 pressure release is not enough, when leading to battery internal pressure further to rise, and insulating seal body 3 is opened and is realized quick pressure release to further improve 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 through hole 115 can also be used for injecting electrolyte into the shell 1, and after the injection is completed through the through hole 115, the sealing element 5 is plugged and sealed through low-temperature tin welding, so that an 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.

Fig. 2 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.

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); the button cell is characterized in that the shell (1) comprises a wall part (111), at least one through hole (115) is formed in the wall part (111), at least one sealing element (5) arranged in the at least one through hole (115) and at least one low-temperature tin (6) for hermetically fixing the at least one sealing element (5) in the at least one through hole (115) are further included.

2. The button cell according to claim 1, wherein the periphery of the outer surface of the sealing member (5) comprises an arc or a slope, so that a filling space is formed between the periphery of the outer surface of the sealing member (5) and the wall of the through hole (115), and the low-temperature tin (6) is deposited on the outer surface of the sealing member (5) and filled in the filling space.

3. Button cell according to claim 1, characterised in that the seal (5) is spherical, the seal (5) interfering by 0-20% with respect to the through hole (115).

4. The button cell as claimed in claim 1, wherein the button cell is a lithium ion cell, and the melting point of the low temperature tin (6) is 100-200 ℃.

5. A button cell according to any one of claims 1-4, characterized in that the wall (111) is further provided with at least one lead-out hole (112), the button cell further comprises at least one conductor (4) inserted into the at least one lead-out hole (112) and at least one insulating seal (3) arranged 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 with one of the at least one positive electrode sheet (21) and the at least one negative electrode sheet (22).

6. Button cell according to claim 5, 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.

7. Button cell according to claim 6, wherein the upper shell (11) comprises the 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 hole (112) extending longitudinally through the wall (111) and the at least one protrusion (113).

8. The button cell according to claim 7, wherein the insulating sealing body (3) comprises a first end (31), a second end (33) and a body portion (32) located between the first end (31) and the second end (33), the body portion (32) is in interference fit in the lead-out hole (112), and the first end (31) and the second end (33) are exposed out of the lead-out hole (112).

9. Button cell according to claim 5, wherein said wall (111) is electrically conductive, said wall (111) being electrically connected to the other of said at least one positive plate (21) and said at least one negative 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), said at least two electrical conductors (4) being electrically connected to said at least one positive electrode tab (21) and said at least one negative electrode tab (22), respectively.