CN111162210A

CN111162210A - Secondary lithium ion bean type battery and manufacturing method thereof

Info

Publication number: CN111162210A
Application number: CN202010180910.8A
Authority: CN
Inventors: 李桂平; 葛辉明; 李碧梅; 李念; 袁中直; 祝媛; 刘金成
Original assignee: Eve Energy Co Ltd
Current assignee: Eve Energy Co Ltd
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-05-15

Abstract

The invention discloses a secondary lithium ion bean type battery and a manufacturing method thereof, wherein the secondary lithium ion bean type battery comprises a shell and a battery cell arranged in the shell, the shell comprises a bottom shell and a cover cap, the bottom shell and the cover cap are both metal pieces, the bottom shell comprises a bottom plate and a first surrounding wall annularly arranged on one side surface of the bottom plate, the cover cap comprises a top plate and a second surrounding wall annularly arranged on one side surface of the top plate, the second surrounding wall is sleeved outside the first surrounding wall, a first arc-shaped part is arranged on the first surrounding wall, a second arc-shaped part matched with the first arc-shaped part is arranged on the second surrounding wall, a first insulating sealing film is adhered to the outer surface of the first surrounding wall, a second insulating sealing film is adhered to the inner surface of the second surrounding wall, and the first insulating sealing film is solidified into an integrated sealing layer after being. The secondary lithium ion bean type battery has the advantages of simple structure, good sealing effect, high space utilization rate and high energy density.

Description

Secondary lithium ion bean type battery and manufacturing method thereof

Technical Field

The invention relates to the technical field of batteries, in particular to a secondary lithium ion bean type battery and a manufacturing method thereof.

Background

A bean cell is a very small size cell, also known as a button cell or button cell. The bean type battery generally comprises a bottom shell, a cover cap and an electric core arranged in a containing cavity formed by the bottom shell and the cover cap, and the sealing difficulty of the bean type battery is very large due to the very small size of the bean type battery. The conventional assembly process for a bean cell is as follows: and (4) sleeving the sealing ring on the bottom shell, placing the battery cell and the like, and covering the cap on the bottom shell for sealing treatment. The bean-type battery thus prepared has the following drawbacks: 1. the upper end of the sealing ring is generally provided with a hook structure to be hung on the top of the bottom shell, the structure and the assembly sealing process of the sealing ring are complex, the manufacturing cost is high, the online production time of the bean type battery can be prolonged, and the capacity can be reduced; 2. the sealing ring part is positioned on the inner wall of the bottom shell, so that the space inside the bottom shell is occupied, and the space utilization rate and the energy density of a battery are reduced; 3. the bean type battery is small in size, so that the thickness of the sealing ring needs to be very thin, the manufacturing difficulty of the sealing ring is increased, meanwhile, the consistency of the thickness and the size of the thin sealing ring is difficult to guarantee, and the sealing performance of the assembled battery is poor.

Disclosure of Invention

One object of an embodiment of the present invention is to: the secondary lithium ion bean type battery is simple in structure, good in sealing effect, high in space utilization rate and high in energy density.

Another object of an embodiment of the present invention is to: the manufacturing method of the secondary lithium ion bean type battery is simple to operate, high in production efficiency and low in production cost.

To achieve the purpose, the embodiment of the invention adopts the following technical scheme:

the first aspect provides a secondary lithium ion bean type battery, is in including shell and setting electric core in the shell, the shell includes drain pan and block, the drain pan with the block is the metalwork, the drain pan includes that bottom plate and ring are established the first leg of a side of bottom plate, the block includes that roof and ring establish the second leg of a side of roof, the second leg cover is established outside the first leg, be provided with first arc portion on the first leg, be provided with on the second leg with first arc portion complex second arc portion, the surface paste of first leg has first insulation seal membrane, the internal surface paste of second leg has second insulation seal membrane, first insulation seal membrane with solidify as an organic whole after the second insulation seal membrane butt and form the sealing layer.

As a preferable mode of the secondary lithium ion bean type battery, the first wall is provided with a plurality of continuous first arc-shaped portions along an axial direction thereof, and the second wall is provided with a plurality of second arc-shaped portions matched with the first arc-shaped portions along the axial direction thereof.

As a secondary lithium ion beans formula battery's an preferred scheme, the surface of drain pan all sets up first insulation seal membrane, the bottom plate surface be provided with the first hole of dodging on the first insulation seal membrane, the internal surface of block all sets up second insulation seal membrane, the roof internal surface be provided with the second on the second insulation seal membrane and dodge the hole, one of them utmost point ear of electricity core passes the second dodge the hole with roof internal surface welds, another utmost point ear of electricity core with the internal surface welds of bottom plate.

As a preferable mode of the secondary lithium ion bean type battery, the first arc-shaped part is annularly arranged on the first surrounding wall, and a plurality of the first arc-shaped parts are parallel along the axial direction of the first surrounding wall; or the like, or, alternatively,

a plurality of first arc-shaped parts are spirally wound on the first surrounding wall along the axial direction of the first surrounding wall; or the like, or, alternatively,

the first arc-shaped part comprises a plurality of sub arc-shaped parts which are arranged along the circumferential direction of the first surrounding wall at intervals.

As a preferable mode of the secondary lithium ion bean type battery, the first arc-shaped part is formed by punching or rolling the first surrounding wall, and the second arc-shaped part is formed by punching or rolling the second surrounding wall.

As a preferable mode of the secondary lithium ion bean type battery, all of the first arc-shaped parts are convexly arranged toward the center of the first surrounding wall, and all of the second arc-shaped parts are convexly arranged toward the center of the second surrounding wall; or the like, or, alternatively,

all the first arc-shaped parts are arranged in a protruding mode towards the center, which is far away from the first surrounding wall, and all the second arc-shaped parts are arranged in a protruding mode towards the center, which is far away from the second surrounding wall; or the like, or, alternatively,

the protruding directions of two adjacent first arc-shaped parts on the first surrounding wall are opposite, the first arc-shaped parts form a first wavy structure on the first surrounding wall, and the second arc-shaped parts on the second surrounding wall form a second wavy structure matched with the first wavy structure.

As a preferable aspect of the secondary lithium ion bean type battery, the cell is a winding type cell or a laminated type cell.

As a preferable scheme of the secondary lithium ion bean battery, the battery cell is a winding battery cell, and a pole piece of the winding battery cell comprises a current collector and an active material coated on the current collector;

the current collector is provided with an extension part which extends to the outside of the active material along the radial direction of the winding type battery cell, the extension part is folded and then partially overlapped, the extension part and the pole piece are arranged in an included angle, and the extension part forms a pole lug; or, the part of the current collector extending to the outside of the active material along the axial direction of the winding type battery cell forms the tab; or, the current collector of the winding type battery cell is provided with an empty foil area, one end of the tab is welded in the empty foil area, and the other end of the tab is connected with the shell.

As a preferable scheme of the secondary lithium ion bean battery, the battery cell is a winding battery cell, and the winding battery cell includes a positive plate, a negative plate and a diaphragm arranged between the positive plate and the negative plate;

the diaphragm is provided with an isolation part extending to two ends of the negative plate along the axial direction of the winding type battery cell, and the isolation part is used for isolating a lug of the winding type battery cell from the end surface of the winding type battery cell; or, two terminal surfaces of coiling formula electricity core all are provided with the insulating piece, the insulating piece is used for keeping apart the utmost point ear of coiling formula electricity core with the terminal surface of coiling formula electricity core.

As a preferable aspect of the secondary lithium ion bean battery, all of the separators are inclined toward the center of the wound cell.

As a preferable scheme of the secondary lithium ion bean battery, a necking part is formed at one end of the second surrounding wall, which is far away from the top plate, and the end part of the necking part abuts against the outer wall of the first surrounding wall or the outer wall of the bottom plate; or the like, or, alternatively,

one end of the second surrounding wall, which is far away from the top plate, is abutted against the outer wall of the first surrounding wall.

As a preferred scheme of the secondary lithium ion bean battery, the battery cell is a winding battery cell, the secondary lithium ion bean battery further includes an auxiliary component, the auxiliary component is a cylinder structure with openings at two ends, and has a first end and a second end which are arranged oppositely, one end of the winding battery cell, which is far away from the bottom plate, is inserted into the first end, and the second end is located above the winding battery cell.

As a preferable mode of the secondary lithium ion bean type battery, the auxiliary member is formed by winding a gummed paper, and the first end of the auxiliary member is adhered to the outer peripheral part of the winding type battery cell; or the like, or, alternatively,

the material of the auxiliary piece is consistent with that of a diaphragm of the winding type battery cell, and the auxiliary piece is wrapped on the peripheral part of the winding type battery cell; or the like, or, alternatively,

the auxiliary part and the winding type battery cell are of an integrated structure.

In a preferred embodiment of the secondary lithium ion bean battery, the insulating sealing film is any one of a CPP film, a PPA film, a modified PP film, and a composite film layer of PPA and PP.

In a second aspect, a method for manufacturing a secondary lithium ion bean battery is provided, in which a battery cell is placed in a bottom case, tabs of the battery cell are respectively welded with the bottom case and a cap, then liquid is injected, the cap is assembled with the bottom case after the liquid is injected, and a first insulating sealing film and a second insulating sealing film between the bottom case and the cap are cured to form a sealing layer after the assembly.

The embodiment of the invention has the beneficial effects that: the insulating sealing films are respectively stuck to the contact positions of the first surrounding wall and the second surrounding wall, so that the thickness consistency of the insulating sealing films stuck to the two surrounding walls is good, the sealing effect can be improved, the insulating sealing films can be very thin, the space utilization rate in the shell can be further increased, and the energy density of the battery can be improved; the two layers of insulating sealing films are solidified into the sealing layer, primary sealing is realized when the two layers of insulating sealing films are abutted, secondary sealing is realized when the two layers of insulating sealing films are solidified into the sealing layer, and the sealing property between the bottom shell and the cover cap is greatly improved by twice sealing; through being provided with corresponding arc portion on first leg and second leg, the setting of arc portion can compress tightly the sealing layer between first leg and second leg, is showing and has promoted the leakproofness between drain pan and the block, and the setting of arc portion can also protect the sealing layer, prevents that the sealing layer from taking place the damage when the block banding, prolongs the life of sealing layer, also guarantees simultaneously that the sealing between drain pan and the block does not become invalid.

Drawings

The invention is explained in more detail below with reference to the figures and examples.

Fig. 1 is a schematic sectional view of a secondary lithium ion bean battery according to a first embodiment of the present invention.

Fig. 2 is an exploded view of fig. 1.

Fig. 3 is a schematic sectional view of a secondary lithium ion bean battery according to a second embodiment of the present invention.

Fig. 4 is an exploded view of fig. 3.

Fig. 5 is a schematic sectional view of a secondary lithium ion bean battery according to a third embodiment of the present invention.

Fig. 6 is an exploded view of fig. 5.

Fig. 7 is a schematic sectional view of a secondary lithium ion bean battery according to a fourth embodiment of the present invention.

Fig. 8 is a schematic sectional view of a secondary lithium ion bean battery according to a fifth embodiment of the present invention.

Fig. 9 is a schematic sectional view of a secondary lithium ion bean battery according to a sixth embodiment of the present invention.

Fig. 10 is a schematic structural diagram of a pole piece and a tab according to an embodiment of the invention.

Fig. 11 is a schematic structural view of a pole piece and a tab according to another embodiment of the present invention.

In the figure:

1. an electric core; 11. a tab; 111. a positive tab; 112. a negative tab; 12. pole pieces; 121. a positive plate; 122. a negative plate; 13. a diaphragm; 131. an isolation section; 14. an extension portion; 15. a reinforcement;

2. a bottom case; 21. a base plate; 22. a first enclosure wall; 23. a first arcuate portion;

3. capping; 31. a top plate; 32. a second enclosure wall; 33. a second arcuate portion; 34. necking part

4. A first insulating sealing film; 41. a first avoidance hole;

5. a second insulating sealing film; 51. a second avoidance hole;

6. an auxiliary member.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Referring to fig. 1 and 2, a secondary lithium ion bean type battery according to an embodiment of the present invention includes a case and a battery cell 1 disposed in the case, the shell comprises a bottom shell 2 and a cap 3, the bottom shell 2 and the cap 3 are both metal pieces, the bottom case 2 comprises a bottom plate 21 and a first surrounding wall 22 annularly arranged on one side surface of the bottom plate 21, the cap 3 comprises a top plate 31 and a second surrounding wall 32 surrounding one side of the top plate 31, the second surrounding wall 32 is sleeved outside the first surrounding wall 22, the first surrounding wall 22 is provided with a first arc-shaped part 23, the second wall 32 is provided with a second arc-shaped part 33 which is matched with the first arc-shaped part 23, a first insulating sealing film 4 is adhered to the outer surface of the first surrounding wall 22, a second insulating sealing film 5 is adhered to the inner surface of the second surrounding wall 32, the first insulating sealing film 4 is cured to form an integral sealing layer after being abutted against the second insulating sealing film 5. By respectively sticking a layer of insulating sealing film at the contact positions of the first surrounding wall 22 and the second surrounding wall 32, the thickness consistency of the insulating sealing films stuck on the two surrounding walls is good, the sealing effect can be improved, the insulating sealing films can be very thin, the space utilization rate in the shell can be further increased, and the energy density of the battery can be improved; the two layers of insulating sealing films are solidified into the sealing layer, primary sealing is realized when the two layers of insulating sealing films are abutted, secondary sealing is realized when the two layers of insulating sealing films are solidified into the sealing layer, and the sealing performance between the bottom shell 2 and the cover cap 3 is greatly improved by the two times of sealing; through being provided with corresponding arc portion on first leg 22 and second leg 32, the setting of arc portion can compress tightly the sealing layer between first leg 22 and second leg 32, show the leakproofness that has promoted between drain pan 2 and the block 3, and the setting of arc portion can also protect the sealing layer, prevent that the sealing layer from taking place the damage when the block 3 banding, the life of extension sealing layer, also guarantee simultaneously that the sealed of drain pan 2 and block 3 between does not become invalid.

The first insulating sealing film 4 adhered to the outer surface of the first surrounding wall 22 may be specifically: the outer surface of the first surrounding wall 22 is entirely covered with the first insulating sealing film 4, or the outer surface portion of the first surrounding wall 22 is covered with the first insulating sealing film 4.

Similarly, the second insulating sealing film 5 adhered to the outer surface of the second surrounding wall 32 may be: the outer surface of the second surrounding wall 32 is entirely covered with the second insulating sealing film 5, or the outer surface portion of the second surrounding wall 32 is covered with the second insulating sealing film 5.

The first insulating sealing film 4 and the first surrounding wall 22 may be formed by: firstly, sticking a first insulating sealing film 4 on the surface of a metal piece, then forming a hole at a corresponding position, then cutting and stamping to form a bottom shell 2, and arranging the first insulating sealing film 4 on the outer surface of a first surrounding wall 22 of the bottom shell 2; secondly, forming holes in the corresponding positions of the first insulating sealing film 4, then adhering the holes to the surface of a metal piece, and then cutting and stamping the metal piece to form the bottom shell 2, wherein the first insulating sealing film 4 is arranged on the outer surface of the first surrounding wall 22 of the bottom shell 2; thirdly, the metal member is cut and punched to form the bottom case 2, and then the first insulating sealing film 4 is attached to the outer surface of the first surrounding wall 22 of the bottom case 2. The second insulating sealing film 5 and the second surrounding wall 32 are formed in the manner described above.

Preferably, referring to fig. 1, 2 and 7, the surface of drain pan 2 all sets up first insulating sealing film 4, bottom plate 21 surface be provided with first dodge hole 41 on the first insulating sealing film 4, the internal surface of block 3 all sets up second insulating sealing film 5, roof 31 internal surface be provided with second dodge hole 51 on the second insulating sealing film 5, preferably, with the size of first dodge hole 41 unanimous with the size of bottom plate 21 for the surface of whole bottom plate 21 can expose. One tab 11 of the battery cell 1 penetrates through the second avoidance hole 51 to be welded to the inner surface of the top plate 31, and the other tab 11 of the battery cell 1 is welded to the inner surface of the bottom plate 21. Insulating seal membrane is pasted entirely to one of them side of drain pan 2 and block 3, the drain pan 2 and the first insulating seal membrane 4 of metal, the block 3 and the second insulating seal membrane 5 of metal all form metal plastic film spare, make whole shell adopt metal plastic film spare to make, need not to set up the sealing washer alone and seal the junction of drain pan 2 and block 3, make fashioned drain pan 2 and block 3 from taking seal structure (being insulating seal membrane) after the metal plastic film spare supplied materials, this process of installation sealing washer has been saved, the production efficiency is promoted, the production cost is reduced. In addition, the arrangement of the first avoidance hole 41 facilitates the conduction of the bottom case 2 and the outside, and the arrangement of the second avoidance hole 51 facilitates the electric connection of the tab 11 and the cap 3. The second avoiding hole 51 is formed in the position, corresponding to the tab 11 to be welded, of the second insulating sealing film 5 on the inner surface of the cap 3, and when the second avoiding hole 51 is formed, attention is paid to the fact that the second insulating sealing film cannot penetrate through the top plate 31 of the cap 3, the first avoiding hole 41 is formed in the first insulating sealing film 4 on the outer surface of the bottom shell 2, and attention is paid to the fact that the first avoiding hole 41 cannot penetrate through the bottom plate 21.

The shell is made of a metal plastic film piece, the hardness of the shell is high, the appearance form of the whole secondary lithium ion bean type battery can be guaranteed to be unchanged, and the situation that the shell deforms due to air expansion in the secondary lithium ion bean type battery can be effectively prevented.

The bottom case 2 and the cap 3 may be a single metal or an alloy material. In the present embodiment, both the bottom case 2 and the cap 3 are stainless steel. In addition, under the premise of ensuring the mechanical strength, metal foil materials can be further adopted, such as: steel foil, and thus, the weight of the battery can be further reduced.

The secondary lithium ion bean type battery is small in size, for example: the diameter is 10mm-13mm, the height is 3mm-6mm, correspondingly, the thickness of the first insulating sealing film 4 and the second insulating sealing film 5 needs to be 0.02mm-0.06mm, the insulating sealing films are directly adhered to metal parts in an outsourcing factory to form metal plastic film parts, after metal plastic film parts are purchased, the metal plastic film parts are cut, stamped and the like to form a shell, the inner surface and the outer surface of the bottom shell 2 and the outer surface of the cover cap 3 need to be clearly distinguished during stamping, so that the first insulating sealing film 4 on the bottom shell 2 after manufacturing and forming is ensured to be located on the outer surface of the bottom shell 2, and the second insulating sealing film 5 on the cover cap 3 is located on the inner surface of the cover cap 3. In other embodiments, the manufactured shell can be purchased directly, that is, when the bottom shell 2 and the cap 3 are purchased back to be finished products, the shape is already formed, and the insulating sealing film is pasted at the corresponding position.

The first insulating sealing film 4 and the second insulating sealing film 5 are both CPP films, PPA films, modified PP films, or composite film layers of PPA and PP.

Compared with other films such as LLDPE, LDPE, HDPE, PET, PVG and the like, the CPP film (namely the casting polypropylene film) has the advantages of lower cost, higher yield, higher stiffness than the PE film, excellent moisture and peculiar smell barrier property, can be used as a base film of a composite material, and can be subjected to metallization treatment.

The PPA film (i.e., polyphthalamide film) is a semi-aromatic polyamide made from terephthalic acid or phthalic acid, and PPA has a semi-crystalline state and a non-crystalline state, has a glass transition temperature of about 255 ℃, and is excellent in heat resistance. In addition, PPA also has better chemical resistance, relatively lower moisture absorption rate, and is stronger and harder than fatty polyamides such as nylon and the like.

Polypropylene (PP) is a semi-crystalline thermoplastic plastic with high impact resistance, high mechanical properties and resistance to corrosion by various organic solvents and acids and bases.

The modified PP film, namely the modified polypropylene film, is also called as a calcium plastic film, has good dimensional stability, low price, higher rigidity, heat resistance and the like compared with pure PP to a certain extent.

Further, the first surrounding wall 22 is provided with a plurality of continuous first arc-shaped portions 23 along the axial direction thereof, and the second surrounding wall 32 is provided with a plurality of second arc-shaped portions 33 matched with the first arc-shaped portions 23 along the axial direction thereof. The tightness of the combination of the bottom shell 2 and the cap 3 can be enhanced by the aid of the plurality of continuously arranged arc-shaped parts, and sealing effect is improved.

As shown in fig. 1 and fig. 2, in this embodiment, the first arc portion 23 is annularly disposed on the first surrounding wall 22, and correspondingly, the second arc portion 33 is also annularly disposed on the second surrounding wall 32, so that the annular arc portion can ensure a good sealing effect, effectively prevent liquid leakage, reduce manufacturing difficulty, and improve production efficiency.

In other embodiments, the arc-shaped portions are not limited to be arranged in an integral annular structure, and each arc-shaped portion may be arranged in an annular interval structure, where the first arc-shaped portion 23 includes a plurality of sub-arc-shaped portions arranged at intervals in the circumferential direction of the first surrounding wall 22, the positions of the sub-arc-shaped portions of two adjacent first arc-shaped portions 23 correspond to each other one by one, correspondingly, the second arc-shaped portion 33 also includes a plurality of sub-arc-shaped portions arranged at intervals in the circumferential direction of the second surrounding wall 32, and the positions of the sub-arc-shaped portions of two adjacent second arc-shaped portions 33 correspond to each other one by one, so that the positions of the first arc-shaped portions 23 and the second arc-shaped portions 33 can be correspondingly fitted.

The sub-arc parts of each first arc part 23 are symmetrically arranged along the central axis of the battery cell 1, and the positions of the sub-arc parts of two adjacent first arc parts 23 are in one-to-one correspondence.

The one-to-one setting means that: in a top view, the sub-arc portions of the uppermost first arc portion 23 completely block the sub-arc portions of the remaining first arc portions 23. Further, a plurality of the first arc-shaped portions 23 may be spirally wound around the first wall 22 in the axial direction of the first wall 22, and correspondingly, a plurality of the second arc-shaped portions 33 may be spirally wound around the second wall 32 in the axial direction of the second wall 32. The spiral winding structure can lead the cap 3 to be screwed on the bottom shell 2, so that the sealing performance is stronger, the abrasion to the sealing layer can be reduced by utilizing the spiral installation, and the service life of the sealing layer is effectively prolonged.

In the present embodiment, the first arc portion 23 is formed by punching or rolling the first surrounding wall 22, and the second arc portion 33 is formed by punching or rolling the second surrounding wall 32. Punching press or roll-in shaping arc portion not only can reduce the manufacturing degree of difficulty, forms the recess that corresponds at the protruding dorsal part of establishing of arc portion, utilizes this recess to hold the arc portion rather than the laminating, realizes closely cooperating.

In a particular embodiment of the invention, as shown in fig. 1 and 2, all of said first arc-shaped portions 23 are set projecting towards the centre of said first peripheral wall 22, and all of said second arc-shaped portions 33 are set projecting towards the centre of said second peripheral wall 32.

In another particular embodiment of the invention, as shown in fig. 3 and 4, all of said first arc-shaped portions 23 are arranged projecting towards the centre facing away from said first peripheral wall 22, and all of said second arc-shaped portions 33 are arranged projecting towards the centre facing away from said second peripheral wall 32.

In another specific embodiment of the present invention, as shown in fig. 5 and 6, the protruding directions of two adjacent first arc-shaped portions 23 on the first wall 22 are opposite, a plurality of first arc-shaped portions 23 form a first wavy structure on the first wall 22, and a plurality of second arc-shaped portions 33 on the second wall 32 form a second wavy structure matching with the first wavy structure. The wave-shaped structure can make the first surrounding wall 22 and the second surrounding wall 32 fit tightly, and the sealing performance is better.

In order to ensure that the bean type battery is not deformed during assembling and edge sealing, the hardness of the first surrounding wall 22 is set to be greater than that of the second surrounding wall 32, the first surrounding wall 22 has greater hardness, and can be used as a supporting substrate, and the deformation of the first surrounding wall 22 (namely the bottom case 2) or the deformation of the first surrounding wall 22 is far less than that of the second surrounding wall 32 in the steps of assembling a sealing layer, the cap 3, sealing the cap 3 and the like, so that the appearance shape and the sealing of the bean type battery are ensured not to fail.

In one embodiment, as shown in fig. 7, a necking portion 34 is formed at an end of the second wall 32 away from the top plate 31, and an end of the necking portion 34 abuts against an outer wall of the first wall 22. The provision of the notch portion 34 can effectively prevent the cap 3 from being detached from the bottom case 2, and can further improve the sealability between the bottom case 2 and the cap 3.

Of course, the end of the necking portion 34 is not limited to abut against the outer wall of the first surrounding wall 22, and as shown in fig. 1 and 2, the second surrounding wall 32 of the cap 3 may be set long enough to extend to the side of the bottom plate 21 away from the first surrounding wall 22 after the cap 3 is assembled on the bottom shell 2, and then the necking portion 34 of the second surrounding wall 32 is subjected to necking, in which the necking portion 34 abuts against the outer wall of the bottom plate 21.

Alternatively, instead of forming the notch 34, as shown in fig. 1, 3 and 5, the end of the second wall 32 may be directly abutted against the outer wall of the first wall 22.

The battery cell 1 of the secondary lithium ion bean battery may be a winding type battery cell 1 (as shown in fig. 1 to 6, 8 and 9) or a laminated type battery cell 1 (as shown in fig. 7), and the winding type battery cell 1 is exemplified as follows.

The winding type battery cell 1 can be in a cylindrical shape, a square column shape, an elliptic column shape and the like.

The winding type battery cell 1 comprises a pole piece 12, a diaphragm 13 and a pole lug 11, wherein the pole piece 12 comprises a positive pole piece 121 and a negative pole piece 122, the pole lug 11 comprises a positive pole lug 111 and a negative pole lug 112, the positive pole lug 111 is connected with the positive pole piece 121, the negative pole lug 112 is connected with the negative pole piece 122, and the positive pole piece 121, the diaphragm 13 and the negative pole piece 122 are sequentially overlapped and then wound to form the winding type battery cell 1.

A positive tab 111 is arranged on a positive plate 121 of the winding type battery cell 1, a negative tab 112 is arranged on a negative plate 122, the positive tab 111 and the negative tab 112 are respectively led out from two ends of the winding type battery cell 1, wherein the positive tab 111 is welded with the cap 3, and the negative tab 112 is welded with the bottom case 2. The positive tab 111 is not limited to be led out from the upper end of the winding type cell 1, and the negative tab 112 is led out from the lower end of the winding type cell 1, but the leading positions of the positive tab 111 and the negative tab 112 may be interchanged, that is, the positive tab 111 is led out from the lower end of the winding type cell 1 to be welded with the bottom case 2, and the negative tab 112 is led out from the upper end of the winding type cell 1 to be welded with the cap 3.

The positive electrode tab 111 and the negative electrode tab 112 are not limited to being disposed at both ends of the wound cell 1, and may be disposed at the same end of the wound cell 1.

In an embodiment, as shown in fig. 10 and 11 (and referring to fig. 1 to 6), the positive electrode tab 121 and the negative electrode tab 122 are similar in shape, each of the electrode tabs 12 includes a current collector and an active material coated on the current collector, the current collector has an extension portion 14 extending to the outside of the active material along a radial direction of the wound battery cell 1, the extension portion 14 is folded and then partially overlapped, the extension portion 14 is disposed at an angle with the electrode tab 12, and the extension portion 14 forms a tab 11. Extension 14 through the mass flow body with pole piece 12 extends to the outside of active material and directly forms utmost point ear 11 after buckling, has saved utmost point ear 11 welded process, has promoted production efficiency, has reduced the internal resistance of coiling formula electricity core 1, and integrated into one piece's utmost point ear 11 and pole piece 12 intensity are higher simultaneously, are difficult for breaking away from.

Of course, as shown in fig. 10 or fig. 11, the current collector has an extension portion 14 extending to the outside of the active material along the axial direction of the wound battery cell 1, the extension portion 14 is directly formed into the tab 11 without bending, specifically, the extension portion 14 is provided in the longitudinal direction of the positive electrode sheet 121 or the negative electrode sheet 122 having a long shape, when the positive electrode sheet 121 or the negative electrode sheet 122 having a long shape is wound along the longitudinal direction, the extension portion 14 is directly formed at both ends of the axial direction of the wound battery cell 1, and then the extension portion 14 of the positive electrode sheet 121 is formed into the positive tab 111, and the extension portion 14 of the negative electrode sheet 122 is formed into the negative tab 112.

Preferably, the superimposed position of the extension 14 is provided with a reinforcement 15. Through set up extra reinforcement 15 in extension 14's coincide position, reinforcement 15 can strengthen the intensity of folding coincide position, is prevented effectively that extension 14 from being broken after bending, protects the integrality of utmost point ear 11, has also strengthened the bulk strength of utmost point ear 11 simultaneously.

The bending angle of the extension portion 14 is flexibly adjusted according to the requirement of the winding type battery cell 1 during packaging, specifically, the extension portion 14 is bent by using the position connected with the end of the pole piece 12 as a pivot, and is bent by using a first included angle α, where the first included angle α is 90 °, and this angle can enable the extension portion 14 to be conveniently led out from two ends of the winding type battery cell 1, shorten the length of the tab 11, and reduce the manufacturing cost.

In a preferred embodiment of the present invention, as shown in fig. 10, the reinforcement member 15 is an adhesive tape wrapped around the outside of the overlapping position of the extension portion 14. Set up the reinforcement 15 into the sticky tape, on the one hand can cushion extension 14 in the coincide position after buckling, can slow down the stress of extension 14 in the department of buckling to a certain extent, effectively reduce the fracture of extension 14 in the coincide position and lead to the phenomenon that utmost point ear 11 and pole piece 12 separate, on the other hand, utilize the sticky tape to play the effect of protection and design to the structure of the coincide position of extension 14, prevent utmost point ear 11 after long-time use, extension 14 takes place to warp and influence the normal use of coiling formula electricity core 1 in the coincide position after buckling. To further enhance the protective effect of the tape on extension 14, multiple layers of tape may be wrapped in an overlapping position.

In another preferred embodiment of the present invention, as shown in fig. 11, the reinforcing member 15 is a double-sided adhesive tape, the extending portion 14 is provided with a first laminating surface and a second laminating surface which are attached to each other at a laminating position, and the double-sided adhesive tape is disposed between the first laminating surface and the second laminating surface. The setting of double faced adhesive tape can prevent effectively that first coincide face and second coincide face from separating to avoid utmost point ear 11 to occupy the space between drain pan 2 and the lid 3.

In addition, the extension part 14 can be bent for multiple times at the same position, so that the thickness of the superposed position is increased, and the strength of the pole piece 12 is further improved.

Certainly, the tab 11 is not limited to be integrally formed with the current collector of the pole piece 12, but may be formed separately, an empty foil area is formed at a reserved position on the current collector of the pole piece 12 without coating an active material, one end of the tab 11 is welded with the empty foil area, and the other end is welded with the bottom case 2 or the cap 3.

In one embodiment, as shown in fig. 8, the separator 13 has a separation part 131 extending to both ends of the negative electrode sheet 122 along the axial direction of the winding type cell 1, and the separation part 131 is used to separate the tab 11 of the winding type cell 1 from the end surface of the winding type cell 1. The setting of isolation 131 can prevent effectively that utmost point ear 11 from taking place the electrical contact with the both ends of the vertical direction of coiling formula electricity core 1, and this isolation 131 and coiling formula electricity core 1 structure as an organic whole need not to set up insulating gasket in addition on the terminal surface of coiling formula electricity core 1, has reduced beans formula battery's the preparation degree of difficulty and cost, has promoted production efficiency, need not to change current beans formula battery's preparation technology and equipment simultaneously, is favorable to beans formula battery's large-scale production, and insulating nature is good.

In this embodiment, the length of the isolation portion 131 extending beyond the end face of the winding type battery cell 1 is not less than 0.75 mm. The design can ensure that the end face of the winding type battery cell 1 formed after the positive plate 121, the negative plate 122 and the diaphragm 13 are wound has the isolating part 131 with enough length so as to insulate and isolate the tab 11 and ensure the insulation effect.

Of course, the isolating part 131 is not limited to be provided to isolate the tab 11 from the end surface of the winding type cell 1, and additional insulating sheets may be provided at the two ends of the winding type cell 1 to isolate the tab 11 from the end surface of the winding type cell 1.

In general, the current collector of the positive electrode tab 121 is an aluminum foil, and the current collector of the negative electrode tab 122 is a copper foil, so the material of the positive electrode tab 111 is an aluminum foil, and the material of the negative electrode tab 112 is a copper foil. The aluminum foil and the copper foil are both softer than an aluminum sheet (tape) or a nickel sheet (tape) which is a material of the conventional tab 11, so that the separator 131 is not easily pierced by the tab 11 when being attached to the end surface of the winding type cell 1.

In order to further improve the safety of the bean cell, a separator 13 having high temperature resistance (130-: an aramid fiber membrane 13.

As shown in fig. 9, the secondary lithium ion bean battery further includes an auxiliary member 6, where the auxiliary member 6 is a cylindrical structure with two open ends and has a first end and a second end that are opposite to each other, one end of the winding type battery cell 1, which is far away from the bottom plate 21, is inserted into the first end, and the second end is located above the winding type battery cell 1. Through setting up auxiliary member 6 in coiling formula electricity core 1's top, this auxiliary member 6 can store electrolyte temporarily, annotate the liquid operation time, annotate liquid equipment and pour into the inside of auxiliary member 6 with electrolyte, electrolyte enters into coiling formula electricity core 1's gap slowly again to absorbed by coiling formula electricity core 1, can prevent effectively that electrolyte from overflowing, can once only pour into sufficient electrolyte into simultaneously, greatly promoted production efficiency, reduced manufacturing cost.

The first end is connected with the end of the winding type battery core 1 far away from the bottom plate 21, and the design can reduce the occupation of the bottom shell 2 and even the inner space of the shell of the whole bean type battery by the auxiliary part 6 as much as possible. Preferably, the first end of the auxiliary element 6 is connected to the outer periphery of the winding type battery cell 1, so that the space for storing the electrolyte in the auxiliary element 6 can be enlarged, and the connection between the auxiliary element 6 and the winding type battery cell 1 is facilitated.

Preferably, the auxiliary member 6 is a cylinder structure, that is, the size of the first end is equal to the size of the second end, and this design can make the diameters of the inner cavity of the auxiliary member 6 consistent everywhere, and during liquid injection, the pressure of the electrolyte in the inner cavity directly acts on the end of the winding type battery cell 1, so that the pressure of the electrolyte in the inner cavity to the winding type battery cell 1 is increased, the absorption of the winding type battery cell 1 to the electrolyte is more facilitated, and the production efficiency of the bean type battery is improved. Of course, in other embodiments, the auxiliary member 6 may also be set to be a horn structure, and the size of the first end is smaller than that of the second end, so that the electrolyte injection can be facilitated by the design, and the precision requirement on the electrolyte injection device is reduced.

In order to provide reference for the injection amount of the electrolyte in the auxiliary part 6, a liquid level height line is arranged in an inner cavity of the auxiliary part 6, the specific height of the electrolyte needing to be temporarily stored in the inner cavity can be calculated before the electrolyte is injected, and then in the actual electrolyte injection process, the electrolyte can be accurately injected only by controlling the electrolyte on the height, so that the accurate control of the injection amount of the electrolyte is facilitated.

In the present embodiment, the auxiliary 6 is formed by winding a tape, and the first end of the auxiliary 6 is attached to the outer peripheral portion of the wound battery cell 1. Because the adhesive tape is thinner and has certain design effect, with adhesive tape wound into auxiliary member 6, annotating the liquid and accomplish the back, need not dismantle auxiliary member 6 from coiling formula electricity core 1, can directly encapsulate the adhesive tape in the shell that drain pan 2 and block 3 are constituteed, hardly occupy the inner space of shell, be convenient for improve battery energy density, reduce the encapsulation degree of difficulty for bean type battery's production efficiency is high. Specifically, the gummed paper may be made of polypropylene (PP) or polyethylene terephthalate (PET) or Polyimide (PI).

It can also act as a tail-out glue when using gummed paper as auxiliary 6, which can further reduce costs.

In other embodiments, the auxiliary member 6 is not limited to being wound with adhesive tape, and may be wound with other materials that do not affect the performance of the battery, such as the same material as the separator 13.

Or the auxiliary member 6 directly forms an integral structure with the winding type battery cell 1, the size of the diaphragm 13 adjacent to the outer ring can be made large, so that the wound diaphragm 13 forms a circle of structure protruding outward from the end face of the winding type battery cell 1 at the end departing from the bottom plate 21 at the periphery of the winding type battery cell 1, and the structure at least surrounds the periphery of the winding type battery cell 1 by a circle to form the auxiliary member 6. This design makes it possible to dispense with the additional production and installation of the auxiliary element 6, so that the auxiliary element 6 is formed after winding of the wound electrical core 1.

The embodiment of the invention also provides a manufacturing method of the secondary lithium ion bean type battery, which comprises the steps of placing the battery core 1 in the bottom case 2, respectively welding the lug 11 of the battery core 1 with the bottom case 2 and the cap 3, then injecting liquid, assembling the cap 3 with the bottom case 2 after the liquid is injected, and solidifying the first insulating sealing film 4 and the second insulating sealing film 5 between the bottom case 2 and the cap 3 to form a sealing layer after the assembly. The manufacturing method is simple to operate, the step of installing the sealing ring is omitted, the production efficiency is greatly improved, in addition, the thickness consistency of the insulating sealing films on the bottom shell 2 and the cover cap 3 is good, secondary sealing is realized by adopting a curing mode, and the sealing effect is greatly improved.

The first insulating sealing film 4 and the second insulating sealing film 5 are cured by heating or radiation.

The specific preparation method comprises the following steps:

s100, providing a metal piece, and cleaning, drying and passivating the surface of the metal piece;

step S200, adhering an insulating sealing film to one side surface of the metal piece by using an adhesive, and performing hot press molding to form a metal plastic film piece (the metal plastic film piece can also be purchased as a finished product);

step S300, forming a hole in a position corresponding to an insulating sealing film of the metal plastic film piece;

step S400, cutting a metal plastic film piece, and stamping to form a bottom shell 2 and a cap 3, wherein a first insulating sealing film 4 of the bottom shell 2 is positioned on the outer surface of the bottom shell, a second insulating sealing film 5 of the cap 3 is positioned on the inner surface of the bottom shell, a first avoidance hole 41 is formed in the first insulating sealing film 4 of the outer wall of the bottom shell 2, and a second avoidance hole 51 is formed in the second insulating sealing film 5 of the inner wall of the cap 3;

step S500, assembling the battery cell 1 in the bottom case 2, and injecting liquid;

step S600, assembling the bottom shell 2 and the cap 3, heating and fusing the joint of the bottom shell 2 and the cap 3, controlling the heating temperature to be 100-1000 ℃, controlling the heating time to be 1-60S, fusing the first insulating sealing film 4 and the second insulating sealing film 5 into a sealing layer, and enabling no gap to exist between the bottom shell 2 and the cap 3 so as to achieve the effect of complete sealing.

Preferably, the heating temperature may be 150 ℃, 160 ℃, 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃.

Preferably, the heating time may be 2s, 3s, 5s, 8s, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55 s.

The forming of dodging the hole is not limited to be set before bottom shell 2 and block 3 stamping forming, can also directly set up well before making metal plastic film spare, is about to insulating seal membrane corresponds the position trompil, pastes the insulating seal membrane after the trompil on the surface of metalwork. Or, after the bottom shell 2 and the cover cap 3 are punched and formed, the avoidance holes are formed at the corresponding positions.

In this embodiment, the thickness of the metal plastic film member is 100 μm to 300 μm.

The adhesive is polyolefin, polyethyleneimine or polyurethane adhesive resin.

In the description herein, it is to be understood that the terms "upper" and the like are based on the orientation or positional relationship shown in the drawings, which are for convenience of description and simplicity of operation, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present invention.

In the description herein, references to the term "an embodiment" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be appropriately combined to form other embodiments as will be appreciated by those skilled in the art.

The technical principle of the present invention is described above in connection with specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive effort, which would fall within the scope of the present invention.

Claims

1. The utility model provides a secondary lithium ion beans formula battery, is in including shell and setting electric core in the shell, a serial communication port, the shell includes drain pan and block, the drain pan with the block is the metalwork, the drain pan includes that bottom plate and ring are established the first leg of a side of bottom plate, the block includes that roof and ring establish the second leg of a side of roof, second leg cover is established outside the first leg, be provided with first arc portion on the first leg, be provided with on the second leg with first arc portion complex second arc portion, the outer surface paste of first leg has first insulation seal membrane, the inner surface paste of second leg has second insulation seal membrane, first insulation seal membrane with solidify as an organic whole after the second insulation seal membrane butt and form the sealing layer.

2. The secondary lithium ion bean-type battery according to claim 1, wherein the first wall is provided with a plurality of consecutive first arc-shaped portions along an axial direction thereof, and the second wall is provided with a plurality of second arc-shaped portions along an axial direction thereof, the second arc-shaped portions being engaged with the first arc-shaped portions.

3. The secondary lithium ion bean type battery of claim 1, wherein the outer surface of the bottom shell is provided with the first insulating sealing film, the outer surface of the bottom plate is provided with a first avoidance hole, the inner surface of the cap is provided with the second insulating sealing film, the inner surface of the top plate is provided with a second avoidance hole, one tab of the battery core passes through the second avoidance hole and is welded to the inner surface of the top plate, and the other tab of the battery core is welded to the inner surface of the bottom plate.

4. The bean-type battery according to claim 2, wherein the first arc-shaped part is annularly arranged on the first surrounding wall, and a plurality of the first arc-shaped parts are parallel along the axial direction of the first surrounding wall; or the like, or, alternatively,

5. The bean battery of claim 2, wherein the first arc is stamped or rolled from the first perimeter wall and the second arc is stamped or rolled from the second perimeter wall.

6. The bean-type battery according to claim 5, wherein all of the first arc-shaped portions are convexly disposed toward a center of the first surrounding wall, and all of the second arc-shaped portions are convexly disposed toward a center of the second surrounding wall; or the like, or, alternatively,

7. The secondary lithium ion bean battery of claim 1, wherein the cell is a wound cell or a laminated cell.

8. The secondary lithium ion bean battery of claim 1, wherein the cell is a wound cell, and the pole piece of the wound cell comprises a current collector and an active material coated on the current collector;

9. The secondary lithium ion bean battery of claim 1, wherein the cell is a wound cell comprising a positive plate, a negative plate, and a separator disposed between the positive plate and the negative plate;

10. The secondary lithium ion bean battery of claim 9, wherein all of the separators are inclined toward the center of the wound cells.

11. The secondary lithium ion bean-type battery according to claim 1, wherein a necking portion is formed at one end of the second surrounding wall, which is far away from the top plate, and the end of the necking portion abuts against the outer wall of the first surrounding wall or the outer wall of the bottom plate; or the like, or, alternatively,

12. The secondary lithium ion bean battery of claim 1, wherein the battery cell is a wound battery cell, and the secondary lithium ion bean battery further comprises an auxiliary member, the auxiliary member is a two-end-opened cylinder structure and has a first end and a second end that are oppositely arranged, one end of the wound battery cell, which is far away from the bottom plate, is inserted into the first end, and the second end is located above the wound battery cell.

13. The secondary lithium-ion bean battery of claim 12, wherein the auxiliary member is formed by winding a gummed paper, and the first end of the auxiliary member is adhered to an outer circumferential portion of the wound battery cell; or the like, or, alternatively,

14. The secondary lithium ion bean-type battery according to claim 1, wherein the insulating sealing film is any one of a CPP film, a PPA film, a modified PP film, and a composite film layer of PPA and PP.

15. A method for manufacturing a secondary lithium ion bean-type battery as claimed in any one of claims 1 to 14, wherein a battery cell is placed in a bottom case, tabs of the battery cell are respectively welded with the bottom case and a cap, then liquid is injected, the cap is assembled with the bottom case after liquid injection, and a first insulating sealing film and a second insulating sealing film between the bottom case and the cap are solidified to form a sealing layer after assembly.