CN106207068B - Preparation method of buried lug type pole piece - Google Patents

Abstract

The invention discloses a method for preparing a buried lug type electrode piece, which comprises the following steps: 1) pre-applying a foam tape on a predetermined position of a current collector; foam tape on the current collector, and then send it to the oven for drying. After reaching the predetermined temperature, the foam tape will thermally debond and expand and curl. 3) Remove the curled foam tape to obtain a pole piece with a reserved blank area. ; 4) Rolling and cutting the pole piece, after cutting, the reserved blank area is at the edge of one side of the pole piece; 5) Welding the tabs in the reserved blank area. In the present invention, the foam tape is used to cover part of the area to fully coat the pole powder and reduce the empty foil at the welding place of the tab. The foam tape expands, curls and falls off at a predetermined temperature, so that the pole tab can be welded inside the pole piece, so that the pole can be freely designed. Process conception of ear position and size is possible.

Description

Preparation method of buried lug type pole piece

technical field

The invention relates to the technical field of lithium-ion battery preparation, in particular to a method for preparing a buried ear-type pole piece.

Background technique

At present, lithium-ion batteries are divided into round batteries, square batteries, and polymer batteries. In the pole group structure, the tabs are basically on the current collector (copper foil or aluminum foil) on one side of the pole piece. Such a structure has the following disadvantages:

1. Since there is no pole powder on the current collector of the welding tab, it is an empty foil. The empty foil in the battery pole piece structure reduces the energy density of the battery because it is not coated with pole powder.

2. On the other hand, for polymer batteries, the hollow foil of the pole piece structure and the lugs on the empty foil are wound inside the pole group, which increases the thickness of the entire pole group itself, which in turn increases the battery life. Thickness, while polymer batteries have very strict requirements on thickness, thickened batteries will have the risk of being unqualified.

Contents of the invention

The object of the present invention is to provide a method for preparing a buried lug type pole piece aiming at the technical defects existing in the prior art.

The technical scheme adopted for realizing the purpose of the present invention is:

A method for preparing a buried lug type pole piece, comprising the following steps,

1) The foam tape is pre-applied on the predetermined position of the current collector, the foam tape includes a tape base layer, an adhesive film layer and an isolation layer arranged from top to bottom, and the adhesive film layer includes 20% -70% by mass of high molecular polymer glue and 30%-80% by mass of heat-expandable microcapsules, the high molecular polymer glue includes 50%-100% by mass of Polysaccharide polymers and 0%-50% by mass fraction of multifunctional olefin polymers;

2) Coat the slurry on the current collector pre-coated with foam tape, and then send it to the oven for drying. After reaching the predetermined temperature, the foam tape will thermally debond and expand and curl.

3) Remove the curled foam tape to obtain a pole piece with a reserved blank area;

4) Rolling and cutting the pole piece, after cutting, the reserved blank area is at the edge of one side of the pole piece;

5) Solder the tabs in the reserved blank area.

The adhesive tape base layer and the adhesive film layer described in the step 1) correspond up and down and form a rectangular die-cut block and are pasted on the isolation layer at intervals, and the cuts are formed on the rectangular die-cut block.

The incision includes four straight lines enclosing a square shape, and intervals are kept between adjacent straight lines.

The incision is a plurality of linear marks arranged at intervals in the transverse direction.

The lengths of the straight line marks alternate with each other.

The foam tape corresponding to the negative plate is treated by plasma surface grafting to improve its hydrophilicity.

In the step 4), the reserved blank area obtained in the step 3) is centered and cut so that two small reserved blank areas are respectively located on the edge of one side of the respective pole piece to weld and connect the tabs respectively.

In step 1), foam tapes are pasted on the front and rear sides of the current collector correspondingly.

The polysaccharide polymer is one or more of chitosan, lactose, maltose and cellulose, and the multifunctional olefin polymer is one of acrylic acid, polyacrylate, polyacrylamide or polyacrylonitrile. species or several.

Compared with prior art, the beneficial effect of the present invention is:

The present invention uses foam tape to cover part of the area to fully coat the pole powder, reducing the empty foil at the welding place of the tab, and the foam tape expands, curls and falls off at a predetermined temperature, so that the pole lug can be welded inside the pole piece, so that the pole can be freely designed The technological conception of the position and size of the ear becomes possible, and the hollow foil of the pole group is less, so that the energy density of the battery is improved, the thickness of the battery is reduced, and the internal resistance of the battery is reduced, and the number of cycles is increased. It paved the way for the research of a new generation of high-volume energy density and high-performance lithium-ion batteries. At the same time, because it can be fully coated and the waiting time for the blank section can be reduced, it can make lithium-ion batteries, especially power batteries, achieve rapid production. The pole piece coating speed can reach 60m/min or higher, which cannot be achieved by conventional methods.

Description of drawings

Fig. 1 shows the top view structure diagram of the buried lug type pole piece of the present invention;

Figure 2 is a schematic diagram of the cross-sectional structure shown in Figure 1;

Figure 3 shows a schematic structural view of the foam tape;

Figure 4 shows a schematic cross-sectional structure of the foam tape;

FIG. 5 is a schematic diagram of another cut structure.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The preparation method of the buried lug type pole piece of the present invention comprises the following steps,

1) Pre-apply the foam tape on the predetermined position of the current collector, such as copper foil or aluminum foil. Among them, multiple ones can be applied on one side, or they can be applied on the front and rear sides of the current collector correspondingly. foam tape,

2) Coat the slurry on the current collector pre-attached with the foam tape, and apply it as double-sided continuous coating or interval coating, or reserve a single-sided area at the end, but the foam tape and the surrounding The current collector at the place is fully coated, and then it is sent to the oven for drying, and at the same time the foam tape starts to thermally detackify and expand and curl, that is, the thermal detackification temperature and the expansion and curling temperature of the foam tape should be the same as those of the slurry That is, the drying temperature of the powder corresponds to the drying time. For the foam tape, the corresponding microcapsules and glue components can be selected, and no further description will be given here.

3) Blow off the curled foam tape at the outlet at the end of the oven to obtain a pole piece with a reserved blank area;

4) Rolling and cutting the pole piece, after cutting, the reserved blank area is at the edge of one side of the pole piece;

5) Solder tabs in the reserved blank area, and paste protective tape, etc., to complete the production of pole pieces.

The present invention uses foam tape to cover part of the area to fully coat the pole powder, reducing the empty foil at the welding place of the tab, and the foam tape expands, curls and falls off at a predetermined temperature, so that the pole lug can be welded inside the pole piece, so that the pole can be freely designed The technological conception of the position and size of the ear becomes possible, and the hollow foil of the pole group is less, so that the energy density of the battery is improved, the thickness of the battery is reduced, and the internal resistance of the battery is reduced, and the number of cycles is increased. It paved the way for the research of a new generation of high-volume energy density and high-performance lithium-ion batteries. At the same time, because it can be fully coated and the waiting time for the blank section can be reduced, it can make lithium-ion batteries, especially power batteries, achieve rapid production. The pole piece coating speed can reach 60m/min or higher, which cannot be achieved by conventional methods.

Specifically, as shown in Figures 3-5, the foam tape includes a tape base layer 1, an adhesive film layer 2 and an isolation layer 3 arranged from top to bottom, and a plurality of cut-through layers are formed on the foam tape. The above-mentioned tape base layer and the cutout of the film layer. The thickness of the foaming tape is 40-65mm, and the thickness of the base layer of the tape is 5-30mm. Among them, the base layer of the tape and the film layer are rectangular die-cut blocks corresponding to the upper and lower sides and pasted on the isolation layer. The rectangular die-cut area of the die-cut is used to limit the size of the single block, which is convenient for high-precision pasting. Each individual die-cut rectangular area is provided with a cutout, which changes the stress of the base layer of the tape and the film layer, making it easier to curl, and improves the regularity of curling, improves the degree of curling, and effectively improves the adaptability of automated production equipment sex.

Preferably, the incision is a plurality of linear marks 4 arranged at intervals in the transverse direction. In terms of specific design, various forms can be adopted. For example, the length of the linear marks is 70%-90% of the length of the corresponding side of the die-cutting area. %, or the lengths of the straight line marks are set alternately and alternately. Or the two straight lines are formed into a group, and the distance between two groups is larger than the distance between two straight lines in one group.

Of course, the cutouts can also be arranged obliquely, that is, not parallel to or perpendicular to the sides of the square area, and the above effects can also be achieved.

As another embodiment, the incision includes four straight lines 5 enclosing a square shape, and intervals are kept between adjacent straight lines. The square cut design with intervals at the four corners makes the adhesive film layer curl towards the center, reduces the attachment points, controls the residual adhesive force, and makes it easy to detach.

The film layer includes 20%-70% by mass of high-molecular polymer glue and 30%-80% by mass of microcapsules, and the high-molecular polymer glue includes 50%-100% The polysaccharide polymer in parts by mass and the multifunctional olefin polymer in 0%-50% by mass.

Specifically, the polysaccharide polymer is one or more of chitosan, lactose, maltose and cellulose, and the multifunctional olefin polymer is acrylic acid, polyacrylonitrile, polyacrylamide or polyacrylic acid One or more acrylates.

That is, the film layer can be directly composed of polysaccharide polymers, such as chitosan and microcapsules mixed in proportion. It can be obtained after drying.

Using polysaccharide polymers such as chitosan as the base material of the adhesive film layer has high viscosity and strong adhesion ability, and the viscosity decays rapidly with the increase of temperature and does not hang glue, which can meet the subsequent welding treatment.

In above-mentioned embodiment, increased the content of microcapsule, film layer all showed good adhesiveness, because high molecular polymer type glue, as chitosan, has the characteristic that heating up cohesiveness reduces simultaneously, both Cooperate with each other, first of all, the foam tape is easy to curl due to the expansion of the microcapsules, and at the same time, the reduction of the viscosity of chitosan can increase the removal rate and avoid surface adhesion. The removal rate of the foam tape increases from 95% to 99%. Improve production efficiency and increase product yield.

The foaming tape of the present invention can be used to be pasted on the foil, and then the slurry is continuously coated, and when the foaming tape is curled off, a relatively clean blank area for electrode piece welding is left on the current collector. When the foamed tape of the present invention is used for water-based slurry coating, because the surface of the foamed tape is hydrophobic, the water-based negative electrode slurry will slide to the edge of the slurry to accumulate, resulting in uneven local thickness of the pole piece coating. Unevenness destroys the pole piece.

In order to improve this problem, it is necessary to increase the hydrophilicity of the foam tape. The foam tape is subjected to plasma surface grafting treatment to graft hydrophilic functional groups such as hydroxyl, carboxyl, and carbonyl. The surface hydrophilicity of the grafted foam tape is significantly improved, and the slurry can be uniformly covered on the surface of the foam tape.

The specific operation steps are as follows:

Put the foam tape in the plasma equipment, adjust the discharge power of the plasma equipment to 12W, adjust the flow rate of the acrylic acid gas so that the discharge vacuum is 30Pa, the discharge time is 1 minute, and the acrylic acid gas is introduced at a speed of 500mL/min. Plasma discharge reaction, after the discharge, continue to feed the reaction gas at the same speed as above for subsequent chemical polymerization, adjust the vacuum degree to 80Pa, and the polymerization time to 0.5 hours. Grafting reaction is carried out on the surface of the heat-pressed PET film to obtain a PET film containing acrylic acid long-chain functional groups.

As shown in Figures 1 and 2, the buried tab pole piece prepared by the preparation method of the present invention includes a pole piece 11 and a pole piece 13, and the pole piece 11 is coated with pole powder except for the reserved blank area. 12. The reserved blank area is located on one side edge of the pole piece and corresponds to the size of the tab 13, and the tab is welded in the reserved blank area. At the same time, stick protective tape 14 on the front and back of the tab to prevent burrs. The current collector is aluminum foil or copper foil, and the electrode powder is the corresponding lithium-ion battery coating material, which is similar to the prior art, and will not be described in detail here.

In the pole piece of the present invention, only a local blank area corresponding to the size of the tab is left on the pole piece and the tab is welded, so that the hollow foil area of the pole piece is reduced, the energy density of the battery is improved, and the effective area of the pole piece is increased. The thickness of the battery is reduced, so that the preparation of a new generation of lithium-ion batteries with high energy density and high performance opens up a new direction.

Specifically, the reserved blank areas are correspondingly formed on the front and rear sides of the pole piece, and a plurality of coated blank areas are arranged on one side of the pole piece. Wherein, in order to facilitate the welding of the pole piece, the width of the coating blank area is 1-4mm wider than the width of the tab, such as 3mm. The width of the protective tape is 1-4mm wider than the width of the coating blank area, such as 3mm.

Example 1

(1) Design buried lugs:

Carry out battery design according to the size requirements of the battery model. Taking the positive plate of polymer battery 405582 as an example, the length of the long powder side of the pole piece is 674mm, the length of the short powder side of the pole piece is 565mm, and the width is 74.8mm. mm, a series of pole piece parameters such as pole piece coating amount 41.70mg/cm2, rolling thickness 112μm, number of cut strips 2;

(2) Design parameters such as the size of the foam tape, the temperature of the foam tape and make the foam tape:

Using foam tape containing foamable microcapsules and chitosan polymer glue, according to the requirements of battery technology and welding tab technology, the size of the empty foil reserved for welding tabs is designed to be 22mm*10mm, that is The size of the foam tape is 22mm*10mm; according to the tape speed of 30m/min, the size of the coating oven is 8m, the maximum temperature for coating and drying is 125°C, and the design temperature of the foam tape is 120°C. Generally, the temperature of the foam tape is lower than the maximum temperature However, it is higher than the sub-high temperature to achieve curling and detachment in the final stage of the oven, and the tape is die-cut, and a designed incision is made on the surface of the tape to achieve the purpose that the tape can expand, curl and detach at the foaming temperature.

(3) Pre-attach the foam tape on the current collector:

According to the design size of the pole piece, the foam tape is evenly pasted on the current collector at equidistant intervals by manual or machine taping.

(4) Electrode coating, rolling, shearing:

Adjust the start-up position by sensing the foam tape, so that the distance from the start-coat position to the foam tape meets the design size, use a coating machine to continuously coat the uniform slurry on the current collector with the foam tape pre-attached, and test the coating The size, coating amount and other parameters are correct, blow off the curled foam tape at the outlet of the pole piece at the end of the oven, and obtain the buried tab pole piece with a reserved blank area in the middle of the pole piece, and roll the pole piece, When cutting, adjust the cutting width and cutting position so that the reserved blank area is at the edge of the pole piece.

(5) Carry out film production and winding;

Carry out the sheet production process: dry the cut pole piece under vacuum drying at 130°C for 4 hours, cut the dried pole piece according to the designed size, and then place it in the reserved Solder the tabs in the blank area, and stick protective tape on the front and back of the tabs to prevent problems such as burrs. After the film production is completed, wind the positive and negative electrodes and the diaphragm together, and make sure the position of the tabs is correct after winding.

(6) Carry out battery liquid injection, packaging, hot pressing, formation, post-treatment and other processes to complete the battery production.

Compared with traditional batteries, the new battery has a 2% increase in energy density, a 1% reduction in battery thickness, and improved internal resistance, rate, and low-temperature performance.

Example 2

(1) Design buried lugs:

Carry out battery design according to the size requirements of the battery model. Taking the positive plate of polymer battery 405582 as an example, the length of the long powder side of the pole piece is 674mm, the length of the short powder side of the pole piece is 565mm, and the width is 74.8mm. mm, a series of pole piece parameters such as pole piece coating amount 41.70mg/cm2, rolling thickness 112μm, number of cut strips 2;

(2) Design parameters such as the size of the foam tape, the temperature of the foam tape and make the foam tape:

Using foam tape containing foamable microcapsules and chitosan glue, according to the requirements of battery technology and welding tab technology, the size of the reserved blank area for welding tabs is designed to be 15mm*15mm, which is the size of the foam tape It is 15mm*15mm; according to the tape speed of 40m/min, the size of the coating oven is 8m, the maximum temperature of coating and drying is 125°C, the design temperature of the foam tape is 120°C, and the tape is die-cut and designed on the surface of the tape In order to achieve the goal that the tape can expand and curl off at the foaming temperature.

(3) Pre-attach the foam tape on the current collector:

According to the design size of the pole piece, the foam tape is evenly pasted on the current collector at equidistant intervals by manual or machine taping.

(4) Electrode coating, rolling, shearing:

Adjust the start-up position by sensing the foam tape, so that the distance from the start-coat position to the foam tape meets the design size, use a coating machine to coat the uniform slurry on the current collector with the foam tape pre-attached, and detect the coating size , Coating amount and other parameters are correct, blow off the curled foam tape at the outlet of the pole piece at the end of the oven, and obtain the buried tab ear piece with a reserved blank area in the middle of the pole piece, and roll and cut the pole piece When cutting, adjust the cutting width and cutting position so that the reserved blank area is at the edge of the pole piece.

(5) Carry out film production and winding;

Carry out the sheet production process: dry the cut pole piece under vacuum drying at 130°C for 4 hours, cut the dried pole piece according to the designed size, and then place it in the reserved Solder the tabs in the blank area, and stick protective tape on the front and back of the tabs to prevent problems such as burrs. After the film production is completed, the positive and negative electrode sheets and the separator are wound together, and the position of the tabs is confirmed to be correct after winding.

(6) Carry out battery liquid injection, packaging, hot pressing, formation, post-treatment and other processes to complete the battery production.

Compared with traditional batteries, the new battery has a 2% increase in energy density, a 1% reduction in battery thickness, and improved internal resistance, rate, and low-temperature performance.

Example 3

(1) Design the electrode piece size of the buried tab, the size of the tab and the related manufacturing process:

Carry out battery design according to the size requirements of the battery model. Taking the positive plate of polymer battery 405582 as an example, the length of the long powder side of the pole piece is 674mm, the length of the short powder side of the pole piece is 565mm, and the width is 74.8mm. mm, a series of pole piece parameters such as pole piece coating amount 41.70mg/cm2, rolling thickness 112μm, number of cut strips 2;

(2) Design parameters such as the size of the foam tape, the temperature of the foam tape and make the foam tape:

Using foam tape containing foamable microcapsules and chitosan glue, according to the requirements of battery technology and welding tab technology, the size of the reserved blank area for welding tabs is designed to be 15mm*15mm, which is the size of the foam tape It is 15mm*15mm; according to the tape speed of 55m/min, the size of the coating oven is 8m, the maximum temperature of coating and drying is 125°C, the design temperature of the foam tape is 120°C, and the tape is die-cut and designed on the surface of the tape In order to achieve the goal that the adhesive tape can expand, curl and detach at the foaming temperature.

(3) Pre-attach the foam tape on the current collector:

According to the design size of the pole piece, the foam tape is evenly pasted on the current collector at equidistant intervals by manual or machine taping.

(4) Electrode coating, rolling, shearing:

Adjust the start-up position by sensing the foam tape, so that the distance from the start-coat position to the foam tape meets the design size, use a coating machine to coat the uniform slurry on the current collector with the foam tape pre-attached, and detect the coating size , coating amount and other parameters are correct, blow off the curled foam tape at the outlet of the pole piece at the end of the oven, and obtain the buried tab electrode piece with a reserved blank area in the middle of the pole piece. The pole piece is rolled and cut, and the cutting width and cutting position are adjusted so that the reserved blank area is at the edge of the pole piece.

(5) Carry out film production and winding;

Carry out the sheet production process: dry the cut pole pieces under vacuum drying at 100°C for 12 hours, cut the dried pole pieces according to the designed size, and then place them in the reserved Solder the tabs in the blank area, and stick protective tape on the front and back of the tabs to prevent problems such as burrs. After the film production is completed, the positive and negative electrode sheets and the separator are wound together, and the position of the tabs is confirmed to be correct after winding.

(6) Carry out battery liquid injection, packaging, hot pressing, formation, post-treatment and other processes to complete the battery production.

Compared with traditional batteries, the new battery has a 2% increase in energy density, a 1% reduction in battery thickness, and improved internal resistance, rate, and low-temperature performance.

Example 4

(1) Design the electrode piece size of the buried tab, the size of the tab and the related manufacturing process:

Carry out battery design according to the size requirements of the battery model. Taking the positive plate of polymer battery 405582 as an example, the length of the long powder side of the pole piece is 674mm, the length of the short powder side of the pole piece is 565mm, and the width is 74.8mm. mm, a series of pole piece parameters such as pole piece coating amount 41.70mg/cm2, rolling thickness 112μm, number of cut strips 2;

(2) Design parameters such as the size of the foam tape, the temperature of the foam tape and make the foam tape:

Using foam tape containing foamable microcapsules and chitosan glue, according to the requirements of battery technology and welding tab technology, the size of the reserved blank area for welding tabs is designed to be 22mm*10mm, which is the size of the foam tape It is 22mm*10mm; according to the tape speed of 3m/min, the size of the coating oven is 8m, the maximum temperature of coating and drying is 125°C, the design temperature of the foam tape is 105°C, and the tape is die-cut, and the design is made on the surface of the tape The transverse cut, as shown in Figure 2, is used to achieve the purpose that the adhesive tape can expand, curl and detach at the foaming temperature.

(3) Pre-attach the foam tape on the current collector:

According to the design size of the pole piece, the foam tape is evenly pasted on the current collector at equidistant intervals by manual or machine taping.

(4) Electrode coating, rolling, shearing:

Adjust the start-up position by sensing the foam tape, so that the distance from the start-coat position to the foam tape meets the design size, use a coating machine to coat the uniform slurry on the current collector with the foam tape pre-attached, and detect the coating size , coating amount and other parameters are correct, blow off the curled foam tape at the outlet of the pole piece at the end of the oven, and obtain the buried tab electrode piece with a reserved blank area in the middle of the pole piece. The pole piece is rolled and cut, and the cutting width and cutting position are adjusted so that the reserved blank area is at the edge of the pole piece.

(5) Carry out film production and winding;

Carry out the sheet production process: dry the cut pole piece under vacuum drying at 130°C for 4 hours, cut the dried pole piece according to the designed size, and then place it in the reserved Solder the tabs in the blank area, and stick protective tape on the front and back of the tabs to prevent problems such as burrs. After the film production is completed, the positive and negative electrode sheets and the separator are wound together, and the position of the tabs is confirmed to be correct after winding.

(6) Carry out battery liquid injection, packaging, hot pressing, formation, post-treatment and other processes to complete the battery production.

Compared with traditional batteries, the new battery has a 2% increase in energy density, a 1% reduction in battery thickness, and improved internal resistance, rate, and low-temperature performance.

Example 5

(1) Design the electrode piece size of the buried tab, the size of the tab and the related manufacturing process:

Carry out battery design according to the size requirements of the battery model. Taking the positive plate of polymer battery 405582 as an example, the length of the long powder side of the pole piece is 674mm, the length of the short powder side of the pole piece is 565mm, and the width is 74.8mm. mm, a series of pole piece parameters such as pole piece coating amount 41.70mg/cm2, rolling thickness 112μm, number of cut strips 2;

(2) Design parameters such as the size of the foam tape, the temperature of the foam tape and make the foam tape:

Using foam tape containing foamable microcapsules and chitosan glue, according to the requirements of battery technology and welding tab technology, the size of the reserved blank area for welding tabs is designed to be 22mm*10mm, which is the size of the foam tape It is 22mm*10mm; according to the tape speed of 60m/min, the size of the coating oven is 8m, the maximum temperature of coating and drying is 125°C, the design temperature of the foam tape is 120°C, and the tape is die-cut and designed on the surface of the tape In order to achieve the goal that the adhesive tape can expand, curl and detach at the foaming temperature.

(3) Pre-attach the foam tape on the current collector:

According to the design size of the pole piece, the foam tape is evenly pasted on the current collector at equidistant intervals by manual or machine tape, and the foam tape is pasted in the middle of the two pre-cut pole pieces, which is convenient for cutting Divide in two when cut.

(4) Electrode coating, rolling, shearing:

Use a coating machine to coat the uniform slurry on the current collector pre-attached with foam tape, check that the coating size, coating amount and other parameters are correct, and blow off the curled hair at the outlet of the pole piece at the end of the oven. Bubble tape to obtain the buried tab electrode sheet with a reserved blank area in the middle of the electrode sheet. The pole piece is rolled and cut. When cutting, the middle cutting process is used to cut the reserved blank area reserved by the foam tape into two halves. Each of the two pole pieces uses half of the reserved blank area for welding. extremely ear.

(5) Carry out film production and winding;

Carry out the sheet production process: dry the cut pole piece under vacuum drying at 130°C for 4 hours, cut the dried pole piece according to the designed size, and then place it in the reserved Solder the tabs in the blank area, and stick protective tape on the front and back of the tabs to prevent problems such as burrs. After the film production is completed, the positive and negative electrode sheets and the separator are wound together, and the position of the tabs is confirmed to be correct after winding.

(5) Carry out battery liquid injection, packaging, hot pressing, formation, post-treatment and other processes to complete the battery production.

Compared with traditional batteries, the new battery has a 2% increase in energy density, a 1% reduction in battery thickness, and improved internal resistance, rate, and low-temperature performance.

Example 6

(1) Design the electrode piece size of the buried tab, the size of the tab and the related manufacturing process:

Carry out battery design according to the size requirements of the battery model. Taking the positive plate of polymer battery 405582 as an example, the length of the long powder side of the pole piece is 674mm, the length of the short powder side of the pole piece is 565mm, and the width is 74.8mm. mm, a series of pole piece parameters such as pole piece coating amount 41.70mg/cm2, rolling thickness 112μm, number of cut strips 2;

(2) Design parameters such as the size of the foam tape, the temperature of the foam tape and make the foam tape:

Using foam tape containing foamable microcapsules and chitosan glue, according to the requirements of battery technology and welding tab technology, the size of the reserved blank area for welding tabs is designed to be 15mm*15mm, which is the size of the foam tape It is 15mm*15mm; according to the tape speed of 50m/min, the size of the coating oven is 8m, the maximum temperature of coating and drying is 125°C, the design temperature of the foam tape is 120°C, and the tape is die-cut and designed on the surface of the tape The transverse cut, as shown in Figure 2, is used to achieve the purpose that the adhesive tape can expand, curl and detach at the foaming temperature.

(3) Pre-attach the foam tape on the current collector:

Two (or more) foam tapes are pasted on one pole piece to weld two (or more) tabs in the middle of the pole piece. According to the design size of the pole piece, the foam tape is pasted by hand or by machine. Attach it evenly to the current collector at equidistant intervals.

(4) Electrode coating, rolling, shearing:

Adjust the start-up position by sensing the foam tape, so that the distance from the start-coat position to the foam tape meets the design size, use a coating machine to coat the uniform slurry on the current collector with the foam tape pre-attached, and detect the coating size , coating amount and other parameters are correct, blow off the curled foam tape at the outlet of the pole piece at the end of the oven, and obtain the buried tab electrode piece with a reserved blank area in the middle of the pole piece. The pole piece is rolled and cut, and the cutting width and cutting position are adjusted so that the reserved blank area is at the edge of the pole piece.

(5) Carry out film production and winding;

Carry out the sheet production process: dry the cut pole piece under vacuum drying at 130°C for 4 hours, cut the dried pole piece according to the designed size, and then place it in the reserved Solder the tabs in the blank area, and stick protective tape on the front and back of the tabs to prevent problems such as burrs. After the film production is completed, the positive and negative electrode sheets and the separator are wound together, and the position of the tabs is confirmed to be correct after winding.

(6) Carry out battery liquid injection, packaging, hot pressing, formation, post-treatment and other processes to complete the battery production.

Compared with traditional batteries, the new battery has a 2% increase in energy density, a 1% reduction in battery thickness, and improved internal resistance, rate, and low-temperature performance.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the protection scope of the present invention.

Claims (7)

1. A method for preparing a buried lug type pole piece, characterized in that, comprising the following steps, 1) The foam tape is pre-applied on the predetermined position of the current collector, and the foam tape includes a tape base layer, an adhesive film layer and an isolation layer arranged from top to bottom, and the foam tape is formed on the foam tape. A plurality of slits that cut through the adhesive tape base layer and the film layer, and the film layer includes 20-70% by mass of high molecular polymer glue and 30-80% by mass of heat-expandable microcapsules, the high molecular polymer glue includes 50-100% by mass of polysaccharide polymer and 0%-50% by mass of multifunctional olefin polymer; 2) Coat the slurry on the current collector pre-coated with foam tape, and then send it to the oven for drying. After reaching the predetermined temperature, the foam tape will thermally debond and expand and curl. 3) Remove the curled foam tape to obtain a pole piece with a reserved blank area; 4) Rolling and cutting the pole piece, after cutting, the reserved blank area is at the edge of one side of the pole piece; 4) Solder the lugs in the reserved blank area; The adhesive tape base layer and the adhesive film layer described in the step 1) correspond up and down and form a rectangular die-cut block and are attached to the isolation layer at intervals, and the otch is formed on the rectangular die-cut block; The foam tape corresponding to the negative plate is treated by plasma surface grafting to improve its hydrophilicity. 2 . The preparation method according to claim 1 , wherein the incision includes four straight lines enclosing a square shape, and intervals are kept between adjacent straight lines. 3 . 3. The preparation method according to claim 1, characterized in that, the cuts are a plurality of linear marks arranged at intervals in the transverse direction. 4. The preparation method according to claim 3, characterized in that, the lengths of the straight line marks alternate with each other. 5. The preparation method according to claim 1, characterized in that, in said step 4), the reserved blank area obtained in step 3) is centered and cut so that two small reserved blank areas are respectively located at The edges on one side of each pole piece are respectively welded to connect the tabs. 6 . The preparation method according to claim 1 , characterized in that, in step 1), foam tapes are correspondingly pasted on the front and rear sides of the current collector. 7 . 7. preparation method as claimed in claim 1 is characterized in that, described polysaccharide polymer is one or more of chitosan, lactose, maltose and cellulose, and described polyfunctional group olefin polymer It is one or more of acrylic acid, polyacrylate ester, polyacrylamide or polyacrylonitrile.