CN103531737A

CN103531737A - Positive plate diaphragm bag, laminated lithium ion battery, and preparation method of laminated lithium ion battery

Info

Publication number: CN103531737A
Application number: CN201310479172.7A
Authority: CN
Inventors: 周晓玲; 何安轩; 殷振国
Original assignee: Shenzhen Grepow Battery Co Ltd
Current assignee: Shenzhen Grepow Battery Co Ltd
Priority date: 2013-05-31
Filing date: 2013-10-14
Publication date: 2014-01-22
Also published as: CN203707224U; CN203503727U; CN103500808A

Abstract

The invention relates to the field of lithium ion batteries and discloses a positive plate diaphragm bag, a laminated lithium ion battery, and a preparation method of the laminated lithium ion battery. The positive plate diaphragm bag is characterized by comprising a first diaphragm layer, a second diaphragm layer and a positive plate, wherein the first diaphragm layer and the second diaphragm layer are aligned and located on the top and the bottom of the positive plate respectively; a heat-sealing opening is formed in at least one wide end part of the first diaphragm layer and the second diaphragm layer; the first diaphragm layer and the second diaphragm layer are connected in a heat melting manner at the heat-sealing opening. The application of the positive plate diaphragm bag is favorable for improving the appearance of a product and improving the electrochemical performance.

Description

Positive plate diaphragm bag, laminated lithium ion battery and preparation method

Technical Field

The invention relates to the field of lithium ion batteries, in particular to a positive plate diaphragm bag, a laminated lithium ion battery and a preparation method thereof.

Background

Lithium ion batteries are widely used because of their high energy density, high output voltage, high output power, and other advantages. The existing lithium ion battery is mainly in the shape of a cylinder, a square, a button and the like, but along with the continuous expansion of the application of the lithium ion battery to various fields, the lithium ion battery in other shapes is more and more concerned, for example, the lithium ion battery applied to a pedometer needs a bent lithium ion battery.

In the course of the research of the present invention, the inventors found that the prior art has at least the following problems:

at present, the bent lithium ion battery in the market is bent by using a jig after the battery is manufactured, so that a pole piece and a structure of the battery are damaged to a great extent, the electrochemical performance of the battery is reduced, and potential safety hazards also exist; in addition, the battery surface is wrinkled during the process of bending the battery, and the appearance is hard to look.

Disclosure of Invention

One of the objectives of the embodiment of the present invention is: the positive plate diaphragm bag is beneficial to improving the appearance of a product and improving the electrochemical performance by applying the technical scheme.

The second purpose of the embodiment of the invention is: the laminated lithium ion battery is beneficial to improving the appearance of a product and improving the electrochemical performance by applying the technical scheme.

The third purpose of the embodiment of the invention is that: the technical scheme is applied to improve the appearance of the product and improve the electrochemical performance.

The fourth purpose of the embodiment of the invention is that: the technical scheme is applied to the preparation method of the laminated lithium ion battery, and the appearance of the laminated lithium ion battery is favorably improved, and the electrochemical performance is improved.

In a first aspect, an embodiment of the present invention provides a positive plate separator bag, including: a first separator layer, a second separator layer, a positive plate,

the first diaphragm layer and the second diaphragm layer are respectively opposite to and cover the top surface and the bottom surface of the positive plate, and the tab welding of the positive plate extends out of the first width of the first diaphragm layer and the first width of the second diaphragm layer;

the first separator layer, the second separator layer, and the positive electrode sheet are bonded together face to face, respectively.

With reference to the first aspect, in a first implementation manner, a polyvinylidene fluoride layer is further disposed between the first separator layer and the positive electrode sheet, and between the second separator layer and the positive electrode sheet,

the first separator layer, the second separator layer and the positive plate are respectively bonded together through the polyvinylidene fluoride layers.

In a second aspect, the laminated lithium ion battery provided by the embodiment of the invention includes any one of the positive plate separator bags described above.

In a third aspect, an embodiment of the present invention provides a laminated lithium ion battery, including:

the arc-shaped laminated electric core body is composed of a negative plate and a positive plate which are laminated and naturally formed into an arc shape, a naturally formed arc diaphragm layer is respectively arranged between any positive plate and any negative plate,

the electric core body concave position is formed on the aluminum-plastic film shell, and the arc-shaped laminated electric core body is limited in the electric core body concave position and sealed by the aluminum-plastic film shell;

each positive plate is respectively limited in each diaphragm bag,

the first diaphragm layer and the second diaphragm layer of the diaphragm bag are respectively opposite to the top surface and the bottom surface of each positive plate;

the first diaphragm layer and the second diaphragm layer are respectively bonded with the positive plate in a face-to-face mode.

With reference to the third aspect, in a first implementation manner, polyvinylidene fluoride layers are further respectively disposed between the first separator layer and the positive electrode sheet, and between the second separator layer and the positive electrode sheet,

With reference to the third aspect, in a first implementation manner, the natural lengths of the positive plate and the negative plate are changed from short to long along the arc-shaped direction of the arc-shaped laminated electrical core body.

In a fourth aspect, an embodiment of the present invention provides a method for manufacturing a laminated lithium-ion battery, including:

a first diaphragm and a second diaphragm are respectively arranged on the top surface and the bottom surface of the positive plate, so that the positive plate is vertically and oppositely covered by the first diaphragm and the second diaphragm,

heat-sealing the first diaphragm, the positive plate and the second diaphragm face to face at a preset temperature and pressure to enable the surfaces of the first diaphragm, the positive plate and the second diaphragm to be bonded together up and down to obtain a positive plate diaphragm bag;

fixing the middle part of the laminated electric core body, naturally placing the laminated electric core body on the top of an arc-shaped support, and hot-pressing the laminated electric core body on the arc-shaped support for preset time to enable each diaphragm layer in the laminated electric core body to be mutually bonded with the positive plate and the negative plate adjacent to the diaphragm layer;

standing the laminated electric core body on the arc-shaped support until the laminated electric core body is shaped into an arc shape matched with the arc-shaped support, so as to obtain an arc-shaped laminated electric core body;

and placing the arc-shaped laminated electric core body into an electric core body concave position of the aluminum-plastic film shell, wherein the radian of the top surface of the electric core body concave position is matched with the radian of the arc-shaped laminated electric core body, so that the bottom surface of the arc-shaped laminated electric core body is attached to the top surface of the electric core body concave position face to face, the top surface of the arc-shaped laminated electric core body covers the top surface aluminum-plastic film layer of the aluminum-plastic film shell, and thermally sealing the aluminum-plastic film to encapsulate the arc-shaped laminated electric core body in the aluminum-plastic film shell, thereby obtaining the laminated lithium ion battery.

With reference to the fourth aspect, in a first implementation manner, a polyvinylidene fluoride layer is further disposed between the first separator layer and the positive electrode sheet, and between the second separator layer and the positive electrode sheet,

face-to-face heat sealing the first diaphragm, the positive plate and the second diaphragm, so that the surfaces of the first diaphragm, the positive plate and the second diaphragm are bonded together from top to bottom, specifically:

Therefore, by applying the technical scheme of the embodiment, after the laminated electric core body of the lithium ion battery is obtained, the middle of the laminated body is fixed, the laminated body is naturally placed on the top of the arc support to be naturally molded, then arc hot press molding and shaping are carried out on the arc, then the concave position of the arc electric core body of the aluminum-plastic film shell is assembled, and then aluminum-plastic film packaging is carried out to obtain the laminated electric core body.

Compared with the prior art, the following technical scheme is that: the method comprises the steps of firstly preparing a finished product of the aluminum-plastic film lithium ion battery with a flat and straight top surface and a flat bottom surface according to the prior art, then bending, pressing and shaping the flat and straight aluminum-plastic film lithium ion battery, wherein in the bending and pressing process, a pole piece and a diaphragm in the lithium ion battery limited in an aluminum-plastic film fixing space are buckled or stretched and deformed, so that the structure of the pole piece of the battery is easily damaged, the electrochemical performance of the battery is reduced, and in addition, in the bending and pressing process, the shell of the aluminum-plastic film is also buckled or stretched and deformed, so that the appearance is unqualified.

In addition, the technical scheme of the positive plate diaphragm bag can greatly improve the production efficiency, is favorable for improving the area of the positive plate in each diaphragm bag and improving the capacity of the battery, realizes the positioning of the positive plate in the diaphragm bag, and avoids the problems of poor electrical performance, even short circuit and potential safety hazard of the lithium ion battery caused by the displacement of the positive plate.

To sum up, use this embodiment technical scheme, because each pole piece, diaphragm and the plastic-aluminum membrane casing in this embodiment arc lithium ion battery all are in natural state and do not pass through deformation stretch forming, are favorable to guaranteeing lithium ion battery's electrochemical performance's stability and security, are favorable to reducing the defective rate of product.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:

fig. 1 is a schematic flow chart of a process for preparing a laminated lithium-ion battery provided in example 1 of the present invention;

FIG. 2 is a schematic flow chart of a preparation scheme of a positive plate diaphragm bag provided in example 1 of the present invention;

FIG. 3 is a schematic flow chart of a preparation scheme of a positive plate diaphragm bag provided in example 1 of the present invention;

FIG. 4 is a schematic diagram of a three-flow process of a preparation scheme of a positive plate diaphragm bag provided in example 1 of the present invention;

fig. 5 is a schematic structural diagram of a positive plate diaphragm bag manufactured in a process according to a preparation scheme of the positive plate diaphragm bag provided in embodiment 1 of the present invention;

fig. 6 is a schematic structural diagram of a positive plate diaphragm bag manufactured in two processes according to the positive plate diaphragm bag manufacturing scheme provided in embodiment 1 of the present invention;

FIG. 7 is a schematic structural diagram of a positive plate diaphragm bag prepared by a three-flow process according to a preparation scheme of the positive plate diaphragm bag provided in example 1 of the present invention;

fig. 8 is a schematic structural view of the devices for forming a lithium ion laminated body, on which the laminated electric core bodies naturally rest according to embodiments 1 and 2 of the present invention;

fig. 9 is a schematic structural diagram of another apparatus for forming a lithium ion laminated body according to embodiment 1 of the present invention;

fig. 10 is a schematic structural diagram of an aluminum-plastic film casing according to embodiment 1 of the present invention;

fig. 11 is a schematic structural view of another aluminum-plastic film casing provided in embodiment 1 of the present invention;

FIG. 12 is a schematic structural view of an arc-shaped laminated aluminum-plastic film lithium ion battery (the side where the liquid injection port is located is not heat-sealed) provided in embodiments 1 and 2 of the present invention;

fig. 13 is a schematic structural view of an aluminum-plastic film arc laminated lithium ion battery provided in embodiments 1 and 2 of the present invention;

fig. 14 is a schematic view of an arcuate laminated electrical core structure provided in embodiments 1 and 2 of the present invention;

fig. 15 is a schematic front view of a side sealing mold for bending an aluminum-plastic film shell according to embodiments 1 and 2 of the present invention;

fig. 16 is a schematic side view of a curved side sealing mold for an aluminum plastic film shell according to embodiments 1 and 2 of the present invention;

fig. 17 is a schematic top view of a curved side sealing mold for an aluminum-plastic film shell provided in embodiments 1 and 2 of the present invention;

fig. 18 is a schematic view of a flow structure of plastic package of an aluminum plastic film housing provided in embodiments 1 and 2 of the present invention.

Reference numerals:

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.

In a first aspect, an embodiment of the present invention provides a method for manufacturing a laminated lithium-ion battery, including:

laminating the negative electrode sheets and the positive electrode sheets to obtain a laminated battery core body, respectively spacing a diaphragm layer between any one of the positive electrode sheets and the negative electrode sheets in the laminated battery core body,

With reference to the first aspect, in a first implementation manner, a top surface and a bottom surface of each of the membrane layers are respectively coated with a polyvinylidene fluoride layer;

and bonding the positive plate and the negative plate adjacent to the diaphragm layer respectively on each diaphragm layer in the laminated cell body, specifically:

and at the hot pressing temperature, all polyvinylidene fluoride layers in the laminated cell body are bonded with the positive plate and the negative plate.

With reference to the first aspect, in a first implementation manner, a stacked electrical core body is obtained by stacking a negative electrode sheet and a positive electrode sheet, and a separator layer is respectively spaced between any one of the positive electrode sheet and the negative electrode sheet in the stacked electrical core body, specifically:

and laminating the negative electrode sheets and the positive electrode sheet diaphragm bags to obtain the laminated electric core body, wherein the positive electrode sheets are respectively arranged in the positive electrode sheet diaphragm bags made of the two diaphragm sheets.

With reference to the first aspect, in a first implementation manner, placing one positive plate in each positive plate separator bag made of two separator plates to obtain each positive plate separator bag includes:

respectively placing a first diaphragm and a second diaphragm on the top surface and the bottom surface of each positive plate to enable the positive plates to be covered by the first diaphragm and the second diaphragm in an up-down opposite manner, thermally sealing at least two longitudinal edges of the first diaphragm and the second diaphragm, respectively forming at least two non-continuous heat-sealing openings on the two longitudinal edges, and thermally connecting the first diaphragm and the second diaphragm at each heat-sealing opening to obtain the positive plate diaphragm bag.

With reference to the first aspect, in a first implementation manner, at least two longitudinal edges of the first membrane and the second membrane are heat-sealed, and at least two non-continuous heat-seal seals are formed on the two longitudinal edges, specifically:

and the peripheral edges of the first diaphragm and the second diaphragm are heat-sealed, and the heat-sealed seals are formed on the peripheral edges of the first diaphragm and the second diaphragm.

respectively placing a first diaphragm and a second diaphragm on the top surface and the bottom surface of each positive plate, so that the positive plates are covered by the first diaphragm and the second diaphragm in a vertically opposite manner, thermally sealing at least one width end part of the first diaphragm and the second diaphragm, forming a heat-sealing opening on the width end part, and thermally connecting the heat-sealing opening of the first diaphragm and the second diaphragm to obtain the positive plate diaphragm bag.

With reference to the first aspect, in a first implementation manner, heat-sealing at least one width end of the first diaphragm and the second diaphragm, specifically:

forming at least two of said heat-seal seals on at least one of said widthwise ends which are not continuous with each other, or,

forming a continuous said heat seal on at least one of said widthwise ends.

heat-sealing the first diaphragm, the second diaphragm and the first width end part of the tab welding part of the positive plate, wherein the tab welding part of the positive plate extends out of the first width end part;

or the second width end parts, opposite to the lug welding part of the positive plate, on the first diaphragm and the second diaphragm are subjected to heat sealing;

or the two width ends of the first diaphragm and the second diaphragm are heat sealed.

respectively placing a first diaphragm and a second diaphragm on the top surface and the bottom surface of each positive plate, so that the positive plates are covered by the first diaphragm and the second diaphragm in a vertically opposite manner, thermally sealing at least any two of four top angles of the first diaphragm and the second diaphragm to form a heat-sealing opening, and thermally connecting the first diaphragm and the second diaphragm at each heat-sealing opening to obtain the positive plate diaphragm bag.

With reference to the first aspect, in a first implementation manner, at least two of the four top corners of the first membrane and the second membrane are heat sealed, specifically;

heat-sealing the four top corners of the first diaphragm and the second diaphragm;

or any two opposite top corners of the first diaphragm and the second diaphragm are subjected to heat sealing.

and heat-sealing the first diaphragm, the positive plate and the second diaphragm face to face at a preset temperature and pressure to bond the surfaces of the first diaphragm, the positive plate and the second diaphragm together up and down to obtain the positive plate diaphragm bag.

and laser spot welding the first diaphragm and the second diaphragm which are laminated along the edges of the first diaphragm and the second diaphragm which exceed the positive plate, so that the first diaphragm and the second diaphragm are connected together, and the positive plate diaphragm bag is obtained.

In combination with the first aspect, in a first implementation manner, in the arc-shaped laminated electrical core body, the natural lengths of the positive plate and the negative plate change from short to long along the arc-shaped direction of the arc-shaped laminated electrical core body.

With reference to the first aspect, in a first implementation manner, top surfaces and bottom surfaces of the first diaphragm and the second diaphragm are respectively coated with a polyvinylidene fluoride layer;

and at the hot pressing temperature, all polyvinylidene fluoride layers in the laminated battery core body are bonded with the positive plate and the negative plate which are adjacent to the polyvinylidene fluoride layers.

With reference to the first aspect, in a first implementation manner, the arc-shaped bracket is in a convex arc shape or a concave arc shape;

the concave position of the electric core body is in a concave arc shape or a convex arc shape.

In a second aspect, the laminated lithium ion battery provided by the embodiment of the invention is obtained by any one of the above preparation methods.

In a third aspect, an embodiment of the present invention provides a method for packaging an aluminum-plastic film of an arc lithium ion battery, where the method includes:

placing an arc-shaped laminated electric core body in the electric core body concave position of the aluminum-plastic film shell, wherein the radian of the top surface of the electric core body concave position is matched with the radian of the arc-shaped laminated electric core body, so that the bottom surface of the arc-shaped laminated electric core body is attached to the top surface of the electric core body concave position face to face,

covering an aluminum-plastic film shell covering sheet on the top surface of the arc-shaped laminated electric core body in an interference manner, wherein the aluminum-plastic film shell covering sheet extends to a first arc-shaped end part of the concave position of the electric core body;

the first upper sealing part and the first lower sealing part which are opposite to each other in the horizontal plane are adopted to heat seal the aluminum plastic film of the second arc-shaped end part between the first upper sealing part and the first lower sealing part, so that the aluminum plastic film shell covering sheet at the second arc-shaped end part is sealed with the aluminum plastic film outside the concave position of the electric core body in a hot melting way, and the second arc-shaped end part is the end part opposite to the first arc-shaped end part;

adopt the second to go up sealing, the second is sealing heat-seal down and is located first arc side between the sealing, the second is sealing down, make first arc side department the plastic-aluminum membrane casing cover piece with the plastic-aluminum membrane hot melt outside the concave position of electric core is sealed together, the bottom of going up the sealing is first curved surface, the top of sealing down is the second curved surface respectively, the cooperation of hugging closely face to face each other of first curved surface, second curved surface, the bottom arc of first curved surface, second curved surface respectively with the top arc of the range upon range of electric core of arc is the same.

With reference to the third aspect, in a first implementation manner, the first curved surface protrudes towards the lower portion;

the second curved surface is recessed towards the lower part;

the top surface of the arc-shaped laminated electrical core is recessed downwards;

with reference to the third aspect, in a first implementation manner, at the step: adopt second upper seal portion, second lower seal portion heat-seal to be located after the first arc side between second upper seal portion, the second lower seal portion, still include:

vacuumizing and pouring electrolyte by taking a second arc-shaped side opening opposite to the first arc-shaped side as a liquid injection opening, so that the arc-shaped laminated electric core body is fully soaked in the electrolyte;

the edges outside the second arc-shaped side surface between the second upper sealing part and the second lower sealing part are heat-sealed by adopting the second upper sealing part and the second lower sealing part to form an air bag;

formation;

and vacuumizing, and thermally sealing the second arc-shaped side surface in the air bag by adopting a second upper sealing part and a second lower sealing part to ensure that the aluminum-plastic film shell covering sheet at the second arc-shaped side surface is sealed with the aluminum-plastic film outside the concave position of the electric core body through hot melting, thus obtaining the arc-shaped aluminum-plastic film laminated lithium ion battery.

In a fourth aspect, an embodiment of the present invention provides an apparatus for forming a lithium ion stacked plate, including:

the top surface of the arc-shaped bracket is arc-shaped;

and a second arc matched with the arc at the top of the arc support is formed at the bottom of the arc pressing die, and when the arc pressing die covers the top of the arc support, the second arc can be in face-to-face contact with the top of the top support.

With reference to the fourth aspect, in a first implementation manner, the top surface of the arc-shaped bracket is in a convex arc shape,

the second arc of the bottom surface of the arc pressing die is an inward concave arc.

With reference to the fourth aspect, in a first implementation manner, the top surface of the arc-shaped bracket is in a concave arc shape,

the second arc of the bottom surface of the arc pressing die is a downward convex arc.

In a fifth aspect, an embodiment of the present invention provides an aluminum-plastic film casing, which is characterized by including:

a concave position of the electric core body is formed on an aluminum plastic film,

the top surface of the concave position of the electric core body is arc-shaped,

a sheet-shaped aluminum-plastic film shell covering sheet extending outside the concave top surface of the electric core body,

the aluminum-plastic film shell covering sheet can cover the top of the concave position of the electric core body.

With reference to the fifth aspect, in a first implementation manner, the arc shape of the top surface of the concave portion of the electrical core body protrudes upwards; or, the arc shape is concave downward.

In a sixth aspect, an embodiment of the present invention provides a laminated lithium ion battery, which is characterized by including:

the arc-shaped laminated electric core body is composed of a negative plate and a positive plate which are laminated and naturally formed into an arc shape, a naturally formed arc-shaped diaphragm layer is respectively arranged between any positive plate and any negative plate,

the electric core body is limited in the electric core body concave position by the arc-shaped laminated electric core body, and the electric core body is sealed by the aluminum-plastic film shell.

With reference to the sixth aspect, in a first implementation manner, each of the separator layers is bonded to the positive electrode sheet and the negative electrode sheet adjacent to the separator layer.

With reference to the sixth aspect, in a first implementation manner, polyvinylidene fluoride layers are respectively coated on the top surface and the bottom surface of each separator layer, and the positive electrode sheet and the negative electrode sheet, which are adjacent to the polyvinylidene fluoride layers, of each polyvinylidene fluoride layer are bonded to each other.

With reference to the sixth aspect, in a first implementation manner, the natural lengths of the positive plate and the negative plate are changed from short to long along the arc-shaped direction of the arc-shaped laminated electrical core body.

With reference to the sixth aspect, in a first implementation manner, each positive electrode plate is respectively limited in each diaphragm bag,

the septum bag comprises: a first diaphragm, a second diaphragm,

the first diaphragm and the second diaphragm are respectively opposite to the top surface and the bottom surface of each positive plate.

With reference to the sixth aspect, in a first implementation manner, each positive electrode plate is respectively limited in each separator bag, specifically:

and at least two discontinuous heat-seal seals are respectively formed on at least two longitudinal edges of the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are in hot-melt connection at each heat-seal.

With reference to the sixth aspect, in a first implementation manner, the heat-seal seals are formed on the peripheral edges of the first diaphragm and the second diaphragm respectively.

the first diaphragm and the second diaphragm are respectively opposite to the top surface and the bottom surface of each positive plate;

and respectively forming heat-seal seals on at least one width end part of the first diaphragm and the second diaphragm, wherein the first diaphragm and the second diaphragm are in hot-melt connection at the heat-seal seals.

With reference to the sixth aspect, in a first mode of realization, at least two of the seals that are not continuous with each other are formed on the width end portions, or,

forming a continuous said heat seal on said widthwise ends; or,

and forming the heat-seal seals on the first width end parts of the first diaphragm and the second diaphragm, wherein the tab welding part of the positive plate extends out of the first width end part.

With reference to the sixth aspect, in a first implementation manner, each positive electrode plate is located in each separator bag,

each positive plate is respectively limited in each diaphragm bag, and the positive plate is specifically as follows:

and heat-seal seals are respectively formed on at least any two of the four top corners of the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are in hot-melt connection at the heat-seal seals.

With reference to the sixth aspect, in a first implementation manner, the heat-seal seals are formed on four top corners of the first diaphragm and the second diaphragm, respectively.

the first diaphragm and the second diaphragm are respectively bonded with the positive plate face to face.

the first diaphragm and the second diaphragm exceed the edges of the positive plates and are connected together through laser spot welding.

In a seventh aspect, an embodiment of the present invention provides an aluminum plastic film packaging mold, which includes an upper sealing portion and a lower sealing portion,

the bottom of the upper sealing part is a first curved surface, the top of the lower sealing part is a second curved surface, and the first curved surface and the second curved surface can be in close fit with each other face to face.

With reference to the seventh aspect, in a first implementation manner, the first curved surface is convex downward, and the second curved surface is concave downward;

or,

the first curved surface is concave upwards, and the second curved surface is convex upwards.

Example 1:

referring to fig. 1 to 18, this embodiment provides a process for manufacturing a laminated lithium-ion battery, which mainly includes the following steps:

step 101: the lamination is carried out to obtain a laminated body.

In this step, negative electrode sheet 1301 and positive electrode sheet 500 are laminated to obtain laminated power core 801. In the obtained laminated electric core 801, a separator layer is interposed between each of the positive electrode sheet 500 and the negative electrode sheet 1301. 1

The step can be realized by adopting a lamination process of a single positive plate 500, a single diaphragm plate and a single negative plate 1301 in the prior art.

As an implementation illustration of this step, the present inventors provide the following lamination solution:

and putting the positive plate 500 into a diaphragm bag to obtain the positive plate diaphragm bag, and respectively putting a positive plate 500 into each positive plate diaphragm bag, so that the active coating layers on the top surface and the bottom surface of the positive plate 500 are covered with diaphragm layers. After each positive electrode pouch is manufactured, each negative electrode sheet 1301 and each positive electrode pouch may be stacked on each other.

The manufacturing of the positive plate diaphragm bag can be realized according to the prior art, namely, the positive plate 500 is arranged in the diaphragm bag with three closed sides, and the lug welding part 5001 of the positive plate 500 extends out of the width end part of the positive plate diaphragm bag.

As an implementation schematic of the step, the inventor also provides the following technical scheme for preparing the positive plate diaphragm bag:

the preparation scheme I of the positive plate diaphragm bag comprises the following steps: the positive plate 500 is respectively filled into each diaphragm bag according to the following bag filling process, so as to obtain each positive plate diaphragm bag, and the bag filling process is as follows, referring to fig. 2 and 5:

step 201: a first separator and a second separator are respectively placed on the top surface and the bottom surface of each positive electrode plate 500.

The active component application region of the positive electrode sheet 500 is covered with the first separator and the second separator in a vertically opposed manner, and the tab welding portion 5001 extends from the first width end of the first separator and the second separator.

Step 202: and at least two longitudinal edges of the first diaphragm and the second diaphragm are heat-sealed, and a plurality of discontinuous heat-seal seals are respectively formed on the two longitudinal edges.

And the first diaphragm and the second diaphragm are in hot-melt connection at each heat-seal sealing position to obtain the positive plate diaphragm bag.

In the present step, the non-connected heat seal can be formed by performing spaced heat sealing only on the first longitudinal edge 501 and the second longitudinal edge 502 of the first membrane and the second membrane;

in this step, the first longitudinal edge 501, the second longitudinal edge 502, and the first width edge 601 of the first and second diaphragms may be heat-sealed at intervals to form heat seals that are not connected to each other;

in this step, the first longitudinal edge 501, the second longitudinal edge 502, the first width edge 601, and the second width edge 602 of the first and second diaphragms may be heat sealed at intervals to form heat seals that are not connected.

Compared with the prior art, the positive plate 500 bagging process shown in the scheme I is adopted, so that on one hand, the positive plate 500 in the diaphragm bag is positioned, and the problems of poor electrical performance, even short circuit and potential safety hazard of the lithium ion battery caused by the displacement of the positive plate 500 are avoided; on the other hand, in the first preparation scheme of the positive plate diaphragm bag, the diaphragm bag is packaged by adopting discontinuous interval heat sealing, so that the periphery of the diaphragm bag is provided with the openings communicated with the outside, and therefore, when liquid is injected, liquid can be better immersed into the positive plate 500 through the diaphragm bag, and the capacity and the electrical property of the laminated lithium ion battery are favorably improved compared with the prior art.

The second preparation scheme of the positive plate diaphragm bag: the positive plate 500 is respectively filled into each diaphragm bag according to the following bag filling process, so as to obtain each positive plate diaphragm bag, and the bag filling process is as follows, referring to fig. 3 and 6:

step 301: a first separator and a second separator are respectively placed on the top surface and the bottom surface of each positive electrode plate 500.

Step 302: and heat-sealing at least one width end of the first diaphragm and the second diaphragm.

In the step, at least one width end part of the first diaphragm and the second diaphragm is heat sealed, a heat seal is formed on the heat sealed width end part, and the first diaphragm and the second diaphragm are in hot melt connection at the heat seal position, so that the positive plate diaphragm bag is obtained.

In this step, the above-mentioned technical scheme of discontinuous interval heat sealing can be adopted, and the technical scheme of continuous heat sealing can also be adopted.

In this step, the heat sealing may be performed only at the first width end portion protruding from the tab welding site of the first separator and the second separator, but not limited to only at the second width end portion opposite to the tab welding site, and also not limited to both width end portions.

Compared with the prior art, by adopting the positive plate 500 bagging process shown in the second preparation scheme of the positive plate diaphragm bag, on one hand, the positioning of the positive plate 500 in the diaphragm bag is realized, and the problems of poor electrical performance, even short circuit and potential safety hazard of the lithium ion battery caused by the displacement of the positive plate 500 are avoided; on the other hand, in the second preparation scheme of the positive plate diaphragm bag, the diaphragm bag is packaged at any one of the two width end parts of the diaphragm or the two width end parts of the diaphragm in a heat sealing mode, so that at least two longitudinal edges of the diaphragm bag are communicated outwards, liquid can be better immersed into the positive plate 500 through the diaphragm bag during liquid injection, and the capacity and the electrical property of a large-size lithium ion battery are favorably improved compared with the prior art.

The third preparation scheme of the positive plate diaphragm bag is as follows: the positive plate 500 is respectively filled into each diaphragm bag according to the following bag filling process, so as to obtain each positive plate diaphragm bag, and the bag filling process is as follows, referring to fig. 4 and 7:

step 401: a first separator and a second separator are respectively placed on the top surface and the bottom surface of each positive electrode plate 500.

Step 402: and at least any two of the four top corners of the first diaphragm and the second diaphragm are heat sealed to form a heat-sealed seal.

In the step, the first diaphragm and the second diaphragm are connected at the heat-seal sealing opening in a hot-melting mode, and the positive plate diaphragm bag is obtained.

In this step, heat sealing may be performed only at any two vertex angles, any three vertex angles, or four vertex angles of the first vertex angle, the second vertex angle, the third vertex angle, and the fourth vertex angle of the first diaphragm and the second diaphragm, and the inventors found that, in the research process of the present invention, when heat sealing is performed only at two vertex angles, a process of heat sealing at a diagonal vertex angle is favorable for better positioning the positive electrode sheet 500; and the four vertex angles are adopted for heat sealing, so that the positive plate 500 can be completely positioned, and the displacement in any direction is avoided.

Compared with the prior art, by adopting the positive plate 500 bagging process shown in the second preparation scheme of the positive plate diaphragm bag, on one hand, the positioning of the positive plate 500 in the diaphragm bag is realized, and the problems of poor electrical performance, even short circuit and potential safety hazard of the lithium ion battery caused by the displacement of the positive plate 500 are avoided; on the other hand, this positive plate diaphragm bag preparation scheme is three because at least two of the diaphragm bag encapsulation at four apex angles of diaphragm carry out the heat-seal, make four edges at the diaphragm bag all communicate to the outside, like this when annotating the liquid, liquid can soak positive plate 500 through the diaphragm bag better, is favorable to improving lithium ion battery's capacity and electrical property greatly for prior art.

The preparation scheme of the positive plate diaphragm bag is four: filling each positive plate 500 into each diaphragm bag according to the following bag filling process to obtain each positive plate diaphragm bag, wherein the bag filling process is as follows:

step 1: a first separator and a second separator are disposed on the top surface and the bottom surface of the positive electrode sheet 500, respectively.

Wherein, the periphery of the diaphragm exceeds the positive plate by about 1-2 mm.

Step 2: and heat-sealing the first diaphragm, the second diaphragm and the pole piece in a face-to-face manner, so that the first diaphragm and the second diaphragm are respectively bonded on the top surface and the bottom surface of the positive pole piece.

In this step, without limitation, polyvinylidene fluoride layers may be coated on the surfaces of the first separator and the second separator, and the first separator and the second separator may be bonded to the positive electrode sheet through the polyvinylidene fluoride layers whose surfaces are semi-molten, respectively, under a hot press at a certain pressure and temperature.

In this embodiment, the single positive plates may be bagged according to the above scheme. Or covering the large first diaphragm and the large second diaphragm on the bottom surface and the top surface of the large positive plate, applying determined temperature and pressure to the laminated first diaphragm, the positive plate and the second diaphragm to enable the first diaphragm, the positive plate and the second diaphragm to be mutually bonded, and then cutting the plates to obtain small single positive plate bags.

By adopting the technical scheme, the production efficiency can be greatly improved, the area of the positive plate in each diaphragm bag is favorably improved, the capacity of the battery is favorably improved, the positioning of the positive plate 500 in the diaphragm bag is realized, and the problems of poor electrical property, even short circuit and potential safety hazard of the lithium ion battery caused by the displacement of the positive plate 500 are avoided.

The preparation scheme of the positive plate diaphragm bag is five: filling each positive plate 500 into each diaphragm bag according to the following bag filling process to obtain each positive plate diaphragm bag, wherein the bag filling process is as follows:

step 1': a first separator and a second separator are disposed on the top surface and the bottom surface of the positive electrode sheet 500, respectively.

Step 2': and thermally sealing the first diaphragm and the second diaphragm at the edges of the first diaphragm and the second diaphragm beyond the positive plate by laser spot welding according to a preset spot welding track, so that the first diaphragm and the second diaphragm are respectively connected together, and the positive plate is limited between the first diaphragm and the second diaphragm.

In this step, adopt laser spot welding to carry out the technical scheme who connects first diaphragm, second diaphragm, because laser spot welding can make its spot welding tie point little and accurate, be favorable to improving the volume of the positive plate in the diaphragm bag, be favorable to improving the capacity of battery, and adopt this technical scheme can improve production efficiency greatly, and realized the location to positive plate 500 in the diaphragm bag, avoid positive plate 500 to shift and lead to the problem of lithium ion battery electrical property not good short circuit even, initiation potential safety hazard.

It should be noted that the above-mentioned preparation schemes of the positive plate and the diaphragm bag are not only suitable for the bagging of the square positive plate, but also suitable for various possible shapes such as round, trapezoid, triangle, and "S" shapes.

Step 102: the laminated electrical core 801 is fixed in the middle.

After the laminated electrical core body 801 is obtained in step 101, the middle portion of the laminated electrical core body 801 may be fixed by, but not limited to, gluing with adhesive tape, so that the two end portions of the laminated electrical core body 801 may naturally sag or naturally roll up under the effect of other upward forces.

Step 103: the arc-shaped hot-press laminates electrical core 801.

Referring to fig. 8, the middle fixed laminated electric core body 801 naturally rests on the top of the arc support 802 of the device for forming the lithium ion laminated stack, and the laminated electric core body 801 naturally clings to and covers the top of the arc support 802 due to the gravity to form an arc shape identical to the top arc shape.

The arc pressing die 803 above the arc supporter 802 is activated to press the lamination stack on the top of the arc supporter 802 at a predetermined pressure with a predetermined temperature of the arc pressing die 803,

the bottom of the arc pressing die 803 is formed with a second arc shape matching the arc shape of the top of the arc support 802, and when the arc pressing die 803 is covered on the top of the arc support 802, it can be in face-to-face contact with the top of the arc support 802. When the laminated electric core 801 is pressed, the arc pressing die 803 is in face-to-face contact with the laminated electric core 801 positioned on the top of the arc support 802, a certain pressure and temperature are uniformly applied to the surface of the laminated electric core 801, and under the action of hot pressing, the positive electrode sheet 500 and the negative electrode sheet 1301, which are adjacent to each other, of each diaphragm layer in the laminated electric core 801 are bonded to each other, that is, the whole laminated electric core 801 is bonded to each other into a whole through bonding of each diaphragm layer.

In this embodiment, the surface of the separator layer or the positive electrode sheet 500 or the negative electrode sheet 1301 may be coated with various materials that can be bonded to each other at a high temperature to achieve the bonding of the separator layer and the adjacent positive electrode sheet 500 or negative electrode sheet 1301.

As an illustration of this embodiment, the present inventors provide that a Polyvinylidene Fluoride (PVDF) material is coated on the top surface and the bottom surface of each separator layer of each separator bag, the PVDF layers are formed on the top surface and the bottom surface of each separator layer, and the hot-pressing temperature is set to a predetermined temperature during the hot-pressing, so that each PVDF layer of each separator layer is softened by heat (softening temperature is 112 to 145 ℃) under the pressure and temperature of the arc-shaped pressing mold 803, and is bonded to the adjacent positive electrode sheet 500 and negative electrode sheet 1301, thereby achieving the mutual bonding of each separator layer to each positive electrode sheet 500 and negative electrode sheet 1301.

In this step, during hot pressing, either the arc pressing mold 803 or the arc support 802 may have a certain temperature, or both may have a certain temperature, so as to improve the hot pressing effect and reduce the hot pressing time.

It should be noted that the structure of the device for forming a lithium ion laminated body of the present embodiment may be configured such that the top of the arc support 802 is configured as an upward-protruding arc as shown in fig. 8, or may be configured such that the top of the arc support 902 is configured as a first arc that is concave toward the bottom as shown in fig. 9, and when the laminated body is placed on the first arc, an upward-protruding arc is formed under the load of the first arc. The bottom of the arc pressing die 903 is set to be a second arc which is matched with the first arc and protrudes towards the bottom, so that the laminated body is pressed face to face.

Step 104: and standing and shaping the laminated electric core body 801 to obtain the arc-shaped laminated electric core body.

And after the hot pressing is carried out for a certain time, the hot pressing is stopped, the laminated electric core body 801 is allowed to stand at the top of the arc-shaped support 802 for a certain time, and the arc-shaped laminated electric core body is obtained after the arc-shaped laminated electric core body is shaped.

In the standing process of the laminated electric core body 801, the laminated electric core body can be stood at normal temperature or cooled and stood; during standing, the arc pressing mold 803 may apply a certain force to the laminated electrical core 801, or may not apply a force to naturally attach the laminated electrical core 801 to the top of the arc support 802 for shaping and forming due to the gravity of the laminated electrical core 801.

Step 105: and packaging the aluminum-plastic film in a shell.

The present embodiment further provides an aluminum-plastic film casing, and referring to fig. 10, the aluminum-plastic film casing of the present embodiment includes an aluminum-plastic film casing covering sheet 1001 and an electrical core concave portion 1002 at a lower position relative to the aluminum-plastic film casing covering sheet 1001. The top surface of the concave position 1002 of the electric core body is arc-shaped, the aluminum-plastic film casing covering sheet 1001 extends to the top of the concave position 1002 of the electric core body, so that after the arc-shaped laminated electric core body is assembled on the concave position 1002 of the electric core body, the aluminum-plastic film casing covering sheet 1001 covers the top surface of the concave position 1002 of the electric core body, the aluminum-plastic film casing covering sheet 1001 and the top surface of the concave position 1002 of the electric core body are naturally attached to the top surface of the arc-shaped electric core body in the aluminum-plastic film casing covering sheet 1001 under the action of gravity, then aluminum-plastic film heat sealing is carried out to.

In this step, the top surface of the electrical core concave portion 1002 of the aluminum-plastic film casing of this embodiment may be designed to be an arc shape that is concave upward and bottom as shown in fig. 10, or the top surface of the electrical core concave portion 1102 may be designed to be an arc shape that is convex upward and top as shown in fig. 11.

In this embodiment, since the electrical core concave 1002 of the aluminum-plastic film casing is arc-shaped, after the electrical core concave 1002 is covered with the aluminum-plastic film casing covering sheet 1001, when plastic packaging is performed on any edge around the electrical core concave 1002, the arc-shaped plastic packaging mold is adopted to perform plastic packaging in cooperation with the arc-shaped electrical core concave 1002, so that the arc-shaped aluminum-plastic film laminated lithium ion battery shown in fig. 12 is obtained.

As an illustration of the present embodiment: when carrying out plastic-aluminum membrane casing heat-seal, can carry out the plastic-aluminum membrane heat-seal with top 1201 in fig. 12 earlier, then with the electrical core concave position 1002 side, carry out the plastic-aluminum membrane heat-seal with the adjacent arc side in plastic-aluminum membrane casing covering piece 1001 extension edge, reserve another arc edge and carry out electrolyte for the opening as annotating the liquid mouth and pour into, then should annotate the tip of liquid mouth place again and seal the gas pocket, become, carry out evacuation secondary heat-seal in the gasbag inboard, can obtain the plastic-aluminum membrane arc lamination electrical core lithium ion battery that fig. 13 shows.

In addition, as an illustration of the present embodiment, the present embodiment may be, but is not limited to, further as shown in fig. 13: the positive plate 500 and the negative plate 1301 with different lengths are selected, the arc-shaped bending degree of the arc-shaped laminated electric core body is matched, the natural lengths of the positive plate 500 and the negative plate 1301 are changed from short to long along the arc-shaped direction of the arc-shaped laminated electric core body, so that laminated bodies which are flat at two end portions of the arc-shaped laminated electric core body and good and tidy in appearance are obtained, and the specification consistency of the laminated lithium ion battery is further improved.

As one of implementation illustrations of this step, this embodiment provides an aluminum plastic film packaging mold particularly suitable for packaging the arc-shaped lithium ion battery of this embodiment, and this mold can be used to package the arc-shaped side of the arc-shaped lithium ion battery.

Referring to fig. 15, 16, and 17, the aluminum-plastic film package mold mainly includes an upper sealing portion 1401 and a lower sealing portion 1402. The bottom of the upper seal 1401 is a first curved surface, the top of the lower seal 1402 is a second curved surface, and the first curved surface and the second curved surface can be closely fitted with each other face to face. Therefore, the arc-shaped side face of the arc-shaped lithium ion battery can be matched with the arc-shaped packaging curved surface for packaging, the packaged aluminum-plastic film can be tightly attached to the arc-shaped electric core, the aluminum-plastic film is prevented from being stretched, and the aluminum-plastic film is prevented from being deformed to cause appearance defective products.

In this embodiment, as shown in fig. 15, 16, and 17, the first curved surface of the upper seal portion 1401 may be designed as a downwardly convex curved surface, and the second curved surface of the lower seal portion 1402 may be designed as a downwardly concave curved surface. The first curved surface of the upper seal 1401 may be designed as an upward concave curved surface, and the second curved surface of the lower seal 1402 may be designed as an upward convex curved surface. Specifically, the design is made according to the arc shape of the concave position 1002 of the electric core in the encapsulated aluminum-plastic film shell.

When the aluminum plastic film is sealed, the upper sealing part 1401 and the lower sealing part 1402 are moved by a cylinder or other propulsion power device, and the upper sealing part 1401 and the lower sealing part 1402 are respectively provided with a certain temperature, and when the aluminum plastic film is sealed by the upper sealing part 1401 and the lower sealing part 1402, the upper aluminum plastic film and the lower aluminum plastic film are thermally fused together under pressure and temperature to realize sealing connection.

As one of implementation illustrations of this step, this embodiment further provides a method for encapsulating an aluminum-plastic film of an arc lithium ion battery by using the above aluminum-plastic film mold, as shown in fig. 18, where the method mainly includes:

step 1801: and loading the arc-shaped laminated electric core.

In this step, the arc-shaped laminated electrical core is placed in the electrical core concave 1002 of the aluminum-plastic film shell, and the radian of the top surface of the electrical core concave 1002 is matched with that of the arc-shaped laminated electrical core, so that the bottom surface of the arc-shaped laminated electrical core is attached to the top surface of the electrical core concave 1002 face to face.

Further details may be found in, but are not limited to, fig. 10, 11, 12 and the corresponding descriptions above.

Step 1802: covers the aluminum plastic film case cover sheet 1001.

Referring to fig. 10 and 9, the aluminum-plastic film covering sheet is covered on the top surface of the arc-shaped laminated electrical core body in an interference manner, so that the aluminum-plastic film covering sheet covers the top surface of the concave portion 1002 of the electrical core body in the interference manner.

In this embodiment, the extending connection end of the aluminum-plastic film housing covering sheet 1001 at the electrical core recess 1002 is referred to as a first arc end, and the other arc end opposite to the first arc end is referred to as a second arc end.

Step 1803: a planar heat seal process encapsulates the second arcuate end portion.

This step can be, but not limited to, using the prior art to realize a planar heat sealing process to seal the first arc-shaped end portion, i.e. the end portion opposite to the extending connection end of the aluminum-plastic film covering sheet. Namely, a first upper sealing part 1401 and a first lower sealing part 1402 which are opposite to each other in a horizontal plane are adopted to heat seal the aluminum plastic film of the second arc-shaped end part between the first upper sealing part 1401 and the first lower sealing part 1402, so that the aluminum plastic film shell covering sheet 1001 at the second arc-shaped end part and the aluminum plastic film outside the electric core concave position 1002 are sealed together in a hot melting mode.

Step 1804: the arc-shaped curved surface is used for heat sealing an arc-shaped side surface.

The curved side surface enclosed here is referred to as the first curved side surface.

The first arc-shaped side surface between the second upper sealing portion 1401 and the second lower sealing portion 1402 is heat-sealed by using a mold shown in fig. 14, 15, and 16 (the upper sealing portion 1401 is referred to as the second upper sealing portion 1401, and the lower sealing portion 1402 is referred to as the second lower sealing portion 1402), and the aluminum plastic film housing covering sheet 1001 on the first arc-shaped side surface and the aluminum plastic film outside the electric core body concave portion 1002 are heat-sealed together.

Similarly, the aluminum plastic film on the second arc-shaped side surface can be heat-sealed by adopting the method of the step 1804, so that the arc-shaped aluminum plastic film lithium ion battery is obtained.

To further facilitate understanding of the present embodiment, the following further explanation is provided in connection with the preparation process of the lithium ion battery.

After step 1804, the following is also performed:

step 1805: and (5) baking at a high temperature.

And (4) baking at high temperature according to the preparation process of the lithium ion battery in the prior art to remove moisture.

Step 1806: and (6) injecting liquid.

With the second arc side that does not carry out the plastic-aluminum membrane heat-seal at present for annotating the liquid mouth, pour into electrolyte toward electric core body concave position 1002, make the range upon range of electric core of arc fill and soak in the electrolyte.

The formation is carried out after the injection, so that the specific injection process can be, but is not limited to, see the prior art.

Step 1807: sealing the air bag.

And (3) adopting an arc side sealing process which is the same as the principle of the step 1804, and packaging the airbag at a position which is a certain distance away from the concave position 1002 of the electric core body on the right side of the second arc side surface.

Step 1808: and (4) formation.

The step enables the electrolyte to fully react, and enables the moisture in the electrolyte and the gas generated in the reaction to be discharged from the air bag so as to be pumped out in vacuum in the following step.

Step 1809: and the vacuumizing cambered surface side seals the second cambered side.

And (3) sealing a second arc-shaped side surface of the concave position 1002 of the electric core body by adopting an arc-shaped side surface which is the same as the arc-shaped side surface of the concave position 1804 and is close to the concave position 1002 of the electric core body in the air bag, and cutting off redundant aluminum plastic films to obtain an arc-shaped lithium ion battery finished product.

As can be seen from the above, with the technical solution of the present embodiment, after the laminated electric core 801 of the lithium ion battery is obtained, by fixing the middle of the laminated sheet, the laminated sheet is naturally placed on the top of the arc support 802 for natural molding, and then arc hot press molding and shaping are performed on the arc, and then the arc electric core concave 1002 of the aluminum-plastic film casing is assembled, and then aluminum-plastic film packaging is performed to obtain the laminated electric core.

Example 2:

referring to fig. 13, the laminated lithium ion battery of the lithium ion battery provided in this embodiment includes: arc-shaped laminated electric core bodies and aluminum-plastic film shells. The structure and the connection relation of each part are as follows:

referring to fig. 14, the arc-shaped laminated electrical core body is composed of a negative plate 1301 and a positive plate 500 which are laminated and naturally formed into an arc shape, a naturally formed arc-shaped diaphragm layer is arranged between any one of the positive plate 500 and the negative plate 1301, and each diaphragm layer is bonded with the positive plate 500 and the negative plate 1301 which are adjacent to the diaphragm layer. Specific preparation processes can be, but are not limited to, those described in example 1.

Referring to fig. 10 or 9, an electrical core concave 1002 is formed on the aluminum-plastic film casing, and the arc-shaped laminated electrical core is limited in the electrical core concave 1002 and sealed by the aluminum-plastic film casing. Specific preparation processes can be, but are not limited to, those described in example 1.

Therefore, by applying the technical scheme of the embodiment, the pole pieces, the diaphragm and the aluminum-plastic film shell of the laminated electric core 801 of the lithium ion battery obtained by the embodiment are all in a natural state and are not subjected to deformation, stretching and molding.

Compared with the prior art, the following technical scheme is that: the method comprises the steps of firstly preparing a finished product of the aluminum-plastic film lithium ion battery with a flat and straight top surface and a flat bottom surface according to the prior art, then bending, pressing and shaping the flat and straight aluminum-plastic film lithium ion battery, wherein in the bending and pressing process, a pole piece and a diaphragm in the lithium ion battery limited in an aluminum-plastic film fixing space are buckled or stretched and deformed, so that the structure of the pole piece of the battery is easily damaged, the electrochemical performance of the battery is reduced, and in addition, in the bending and pressing process, the shell of the aluminum-plastic film is also buckled or stretched and deformed, so that the appearance is unqualified. Therefore, the technical scheme of the embodiment is favorable for ensuring the stability and the safety of the electrochemical performance of the lithium ion battery and reducing the reject ratio of products.

As a schematic one of this embodiment, referring to fig. 5, in the arc-shaped laminated battery core of this embodiment, each positive electrode sheet 500 may be respectively assembled in each separator bag, and each separator bag includes: a first diaphragm and a second diaphragm. Wherein the first diaphragm and the second diaphragm are respectively opposite to the top and the bottom of each positive plate 500; at least two discontinuous heat-seal seals are respectively formed on at least two longitudinal edges of the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are in hot-melt connection at each heat-seal. Further specific preparation processes and advantageous effects can be seen, but are not limited to, the corresponding descriptions in example 1.

Optionally, in the arc-shaped laminated electrical core body of the embodiment, in each positive plate separator bag, each discontinuous spaced heat-seal is respectively disposed on the peripheral edges of the first separator and the second separator. Further specific preparation processes and advantageous effects can be seen, but are not limited to, the corresponding descriptions in example 1.

As a second schematic diagram of the present embodiment, referring to fig. 6, in the arc-shaped laminated battery core of the present embodiment, each positive electrode sheet 500 may be respectively assembled in each separator bag, and each separator bag includes: a first diaphragm and a second diaphragm. Wherein the first diaphragm and the second diaphragm are respectively opposite to the top and the bottom of each positive plate 500; and respectively forming heat-seal seals on at least one width end part of the first diaphragm and the second diaphragm, wherein the first diaphragm and the second diaphragm are in hot-melt connection at the heat-seal seals.

Alternatively, in the arc-shaped laminated cell body of the embodiment, the heat seal formed at the end of the width may be a non-continuous heat seal at intervals, or may be a continuous heat seal.

Alternatively, in the arc-shaped laminated cell body of the present embodiment, the heat-seal seals described above may be provided on the first separator, the second separator, and the first width end portion of the positive electrode sheet 500 from which the tab welding portion 5001 extends, the heat-seal described above may be provided on the second width end portion of the positive electrode sheet 500 opposite to the tab welding portion 5001, and the heat-seal seals described above may be provided on both ends. Further specific preparation processes and advantageous effects can be seen, but are not limited to, the corresponding descriptions in example 1.

Referring to fig. 7 as a third schematic diagram of the present embodiment, in the arc-shaped laminated battery core of the present embodiment, each positive electrode sheet 500 may be respectively assembled in each separator bag, and each separator bag includes: a first diaphragm and a second diaphragm. Wherein the first diaphragm and the second diaphragm are respectively opposite to the top and the bottom of each positive plate 500; and heat-seal seals are respectively formed on at least any two of the four top corners of the first diaphragm and the second diaphragm, and the first diaphragm and the second diaphragm are in hot-melt connection at the heat-seal seals.

Optionally, in the arc-shaped laminated battery cell body in this embodiment, heat sealing may be performed only at any two vertex angles, any three vertex angles, or four vertex angles of the first vertex angle, the second vertex angle, the third vertex angle, and the fourth vertex angle of the first diaphragm and the second diaphragm, and the inventor of the present invention finds that, in the research process of the present invention, when heat sealing is performed only at two vertex angles, a process of heat sealing at diagonal vertex angles is favorable for better positioning the positive electrode sheet 500; and the four vertex angles are adopted for heat sealing, so that the positive plate 500 can be completely positioned, and the displacement in any direction is avoided. Further specific preparation processes and advantageous effects can be seen, but are not limited to, the corresponding descriptions in example 1.

Example 3:

the laminated lithium ion battery provided in this embodiment is different from embodiment 2 only in that, in this embodiment, the positive plate 500 and the negative plate 1301 with different lengths are selected, so that the arc camber of the arc-shaped laminated core body is matched, and the natural lengths of the positive plate 500 and the negative plate 1301 are changed from short to long along the arc-shaped direction of the arc-shaped laminated core body, so as to obtain a laminated body with flat two end portions of the arc-shaped laminated core body and good and tidy appearance, which is further beneficial to improving the specification consistency of the laminated lithium ion battery.

Test comparison analysis:

to further illustrate the technical effects of the present example, the following description is made by analyzing the comparative file test of the comparative example and the inventive example with the same model specification:

comparative example: the method comprises the following steps of directly bending and pressing aluminum plastic film lithium ion batteries on upper and lower planes by using the prior art to obtain an arc-shaped lithium ion battery;

example 1: by adopting the embodiment 1, the arc-shaped laminated electric core body formed by natural non-deformation is obtained, and the arc-shaped laminated electric core body is assembled in the concave position of the arc-shaped electric core body to be packaged by the aluminum plastic film, so that the arc-shaped lithium ion battery is obtained, wherein the pole piece bag adopts a first preparation scheme of a positive pole piece diaphragm bag;

example 2: by adopting the embodiment 1, the arc-shaped laminated electric core body formed by natural non-deformation is obtained, and the arc-shaped laminated electric core body is assembled in the concave position of the arc-shaped electric core body to be packaged by the aluminum plastic film, so that the arc-shaped lithium ion battery is obtained, wherein the pole piece bag adopts a second preparation scheme of a positive pole piece diaphragm bag;

example 3: by adopting the embodiment 1, the arc-shaped laminated electric core body formed by natural non-deformation is obtained, and the arc-shaped laminated electric core body is assembled in the concave position of the arc-shaped electric core body to be packaged by the aluminum plastic film, so that the arc-shaped lithium ion battery is obtained, wherein the pole piece bag adopts a third preparation scheme of a positive pole piece diaphragm bag;

the electrochemical performance of the lithium ion battery was tested on 1000 battery samples, respectively, to obtain the data shown in table one:

table one: data result comparison table for electrical property experiment

Therefore, the technical scheme of the embodiment is favorable for reducing the appearance reject ratio of the product and improving the electrochemical performance of the product.

The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.

Claims

1. A positive plate diaphragm bag is characterized by comprising: a first separator layer, a second separator layer, a positive plate,

2. The positive plate separator bag according to claim 1,

polyvinylidene fluoride layers are respectively arranged between the first diaphragm layer and the positive plate and between the second diaphragm layer and the positive plate,

3. A laminated lithium ion battery having the positive plate separator bag according to claim 1 or 2.

4. A laminated lithium ion battery, comprising:

each positive plate is respectively limited in each diaphragm bag,

5. The laminated lithium-ion battery of claim 4,

6. The laminated lithium-ion battery according to claim 4 or 5,

and the natural lengths of the positive plate and the negative plate are changed from short to long along the arc-shaped direction of the arc-shaped laminated electric core body.

7. A method for preparing a laminated lithium ion battery is characterized by comprising the following steps:

stacking the negative pole pieces and the positive pole piece diaphragm bags to obtain a stacked electric core body, wherein a diaphragm layer is respectively arranged between any one of the positive pole pieces and the negative pole pieces in the stacked electric core body,

8. The method of claim 7, wherein the laminated lithium ion battery is prepared by the method,

9. The method of claim 7 or 8, wherein the laminated lithium ion battery is prepared by the method,

the arc-shaped laminated battery core body is internally provided with an arc-shaped laminated battery core body, and the natural lengths of the positive plate and the negative plate are changed from short to long along the arc-shaped laminated battery core body from inside to outside.