CN111774195A - A negative electrode pole piece lithium powder supplementing lithium device - Google Patents

Abstract

The invention provides a lithium supplementing device for lithium powder of a negative pole piece, which comprises an electrostatic lithium supplementing mechanism, wherein the electrostatic lithium supplementing mechanism comprises an electrostatic generating assembly, a plurality of spraying needle tubes, a slurry pump, an electrostatic collecting roller and a lithium powder slurry supplying assembly, the electrostatic collecting roller and the spraying assembly are oppositely arranged and are respectively positioned on two sides of the pole piece in the conveying direction, the electrostatic collecting roller is grounded, the electrostatic generating assembly is used for enabling lithium powder sprayed to the pole piece by the spraying needle tubes to be negatively charged, the spraying assembly comprises a plurality of spraying needle tubes, the spraying needle tubes are arranged at intervals in the width direction of the pole piece, the spraying needle tubes are all vertically directed to the pole piece, the lithium powder slurry supplying assembly and the slurry pump are communicated through a pipeline, and the slurry pump is respectively communicated with the spraying needle tubes through a pipeline. According to the invention, the pole piece can be subjected to pre-lithiation through the matching of the static electricity generation assembly, the static electricity collection roller and the injection assembly, and the number of the injection needle tubes is adjusted according to the actual width of the pole piece, so that the pre-lithiation is more uniform.

Description

A negative electrode pole piece lithium powder supplementing lithium device

technical field

The invention relates to the technical field of lithium batteries, in particular to a lithium powder supplementing device for a negative electrode pole piece.

Background technique

At present, lithium-ion secondary batteries are widely used in the market due to their high single energy density and recyclable times. When used as a power battery, energy density is an important performance requirement that people pursue. At present, the use of high-nickel ternary cathode materials and silicon anode materials is an important development direction for lithium-ion battery developers to improve battery energy density. Compared with the graphite anode material, the silicon anode material consumes a large amount of lithium ions for the formation of the SEI film during the first charging process of the battery, which is equivalent to the content of lithium ions in the consumed cathode material, thereby reducing the battery capacity. Therefore, lithium supplementation of silicon anode or Si-C anode material containing silicon in advance plays an important role in improving the capacity of the battery.

Lithium supplementation of the negative electrode is the pre-lithiation of the negative electrode. The lack of mature equipment and high production costs are the main problems that limit the difficulty of the pre-lithium process to achieve industrial production. There are many methods for replenishing lithium in the negative electrode, which mainly include several methods such as electrochemical lithium replenishment, rolling lithium foil replenishment, vacuum lithium plating and metal lithium powder. Stable lithium powder supplementation is one of the earliest methods of lithium supplementation. It is often used in the manufacture of pre-lab and miniaturized experimental batteries. The operation is simple and the effect is obvious. Just sprinkle lithium powder on the surface of the pole piece to complete the pre-lithiation. However, in industrial application, the direct use of lithium powder is prone to flying, and it is very easy to cause safety problems. Therefore, it is necessary to use specific methods and equipment to supplement lithium. For example, the patent application No. 201210237240.4 discloses a method for directly depositing lithium powder using an electric field to supplement lithium in the negative electrode sheet. Although this method can complete lithium supplementation, the lithium powder inlet The uniformity of only one in the electric field environment is very difficult, the deposition of lithium powder takes a long time to reach the negative electrode sheet, and the efficiency is poor, and the floating lithium powder is more prone to the danger of fire and explosion.

Another example is the patent of Application No. 201811193753.3, which discloses a separator for lithium supplementation of silicon carbon negative electrode. The separator is composed of metal lithium powder, a binder and a lithium ion battery separator. The thickness of the separator is usually very thin, and the lithium powder directly deposited on the separator can easily penetrate the separator and cause the risk of battery short circuit, and the excess lithium powder in the edge area cannot be fully utilized.

SUMMARY OF THE INVENTION

In order to solve the technical problems existing in the background art, the present invention proposes a lithium powder supplementing device for a negative electrode pole piece.

A negative electrode pole piece lithium powder replenishing device provided by the present invention includes an electrostatic lithium replenishing mechanism, and the electrostatic lithium replenishing mechanism includes an electrostatic generating component, a plurality of jet needles, a slurry pump, an electrostatic collecting roller and a lithium powder slurry supply component;

The electrostatic collecting roller and the spraying assembly are oppositely arranged and located on both sides of the pole piece conveying direction, the electrostatic collecting roller is grounded, and the static electricity generating assembly is used to negatively charge the lithium powder sprayed by the spraying needle to the pole piece;

The jetting assembly includes a plurality of jetting needles, the plurality of jetting needles are arranged at intervals along the width direction of the pole piece, and the plurality of jetting needles are all directed vertically to the pole piece, the lithium powder slurry supply assembly and the slurry pump are communicated through pipes, and the slurry pump is connected to the A plurality of injection needles are communicated through pipes.

Preferably, the slurry pump is a variable frequency pump.

Preferably, a flow meter is provided on the pipeline between the variable frequency pump and each injection needle.

Preferably, it also includes two limit baffles and an adjustment and fixing assembly, the two limit baffles are arranged on the side of the electrostatic collection roller facing the pole piece along the axial interval of the electrostatic collection roller, the two limit baffles and the electrostatic collection roller The collection rollers are slidably matched, and there are adjustment and fixing components between the two limit baffles and the electrostatic collection roller. The adjustment and fixing components are used to make the corresponding limit plates move along the axial direction of the electrostatic collection rollers. A space for the passage of the pole pieces is formed therebetween.

Preferably, the adjusting and fixing assembly includes a roller frame and two locking and fixing parts, the electrostatic collecting roller is rotatably arranged on the roller frame, the roller frame is provided with a guide rod parallel to the axis of the electrostatic collecting roller, and the two limit baffles are respectively It is fixed on the guide rod by locking the fixing piece, and the connection between the limit baffle plate and the guide rod can be adjusted along the length direction of the guide rod.

Preferably, there are two electrostatic lithium replenishing devices, the two electrostatic lithium replenishing devices are arranged at intervals along the conveying direction of the pole piece, and the two electrostatic lithium replenishing devices are respectively used to replenish lithium on both sides of the pole piece.

Preferably, two drying mechanisms are also included, and the two drying mechanisms are disposed downstream of the two electrostatic lithium supplementing mechanisms in a one-to-one correspondence.

Preferably, the drying mechanism is a hot air drying mechanism.

Preferably, it also includes an unwinding mechanism, a rolling mechanism and a winding mechanism, an unwinding mechanism, an electrostatic lithium replenishing mechanism, a drying mechanism, an electrostatic lithium replenishing mechanism, a drying mechanism, a rolling mechanism and a winding mechanism along the conveying direction of the pole piece Sequentially set the interval.

The negative electrode pole piece lithium powder lithium supplementing device proposed by the present invention has the following beneficial effects:

(1) The lithium powder is adsorbed on the pole piece through the cooperation of the static electricity generating component and the electrostatic collecting roller, and the lithium is replenished evenly, and the pole piece is grounded by contacting the pole piece with the electrostatic collecting roller. workload, more convenient to use.

(2) The pole piece is supplemented with lithium through a plurality of injection needles arranged at intervals along the width direction of the pole piece. The injection needle makes the injection range and injection speed more accurate, and can improve the uniformity of lithium replenishment.

(3) It can be applied to the pre-lithium of the pole pieces of different battery types by adjusting the number of injection needles.

Description of drawings

FIG. 1 is a schematic structural diagram of a lithium powder supplementing device for a negative electrode pole piece proposed by the present invention.

FIG. 2 is a schematic view of the structure of the electrostatic collecting roller in the present invention.

Description of reference numbers:

1-unwinding mechanism 2-winding mechanism 3-static collecting roller 4-jet needle 5-drying mechanism

6-Rolling mechanism 7-Limit baffle

Detailed ways

Hereinafter, the technical solutions of the present invention will be described in detail through specific embodiments.

Referring to FIG. 1 , a negative electrode pole piece lithium powder replenishing device for lithium proposed by the present invention includes an electrostatic lithium replenishing mechanism, and the electrostatic lithium replenishing mechanism includes an electrostatic generating assembly, a plurality of injection needles 4, a slurry pump, an electrostatic collection roller 3 and a lithium Powder slurry supply component;

The electrostatic collecting roller 3 and the spraying assembly are arranged opposite to each other and are located on both sides of the pole piece conveying direction, the electrostatic collecting roller 3 is grounded, and the electrostatic generating assembly is used to negatively charge the lithium powder sprayed by the spraying needle 4 to the pole piece, so that the negatively charged lithium powder is charged. Lithium powder is adsorbed on the pole piece due to electrostatic force;

The jetting assembly includes a plurality of jetting needle tubes 4, the plurality of jetting needle tubes 4 are arranged at intervals along the width direction of the pole piece, and the plurality of jetting needle tubes 4 are vertically directed to the pole piece, the lithium powder slurry supply assembly and the slurry pump are communicated through pipes, and the slurry The pumps are respectively communicated with the plurality of injection needles 4 through pipes.

When replenishing lithium in the present invention, the electrostatic collecting roller 3 contacts the pole piece, and the grounding of the electrostatic collecting roller 3 can make the pole piece grounded, and the grounding piece does not need to be fixed with the pole lug of the pole piece, which reduces the workload and is more convenient to use. The lithium powder sprayed by the injection needle 4 to the pole piece is negatively charged, so that the negatively charged lithium powder is adsorbed on the pole piece due to the action of electrostatic force to complete the lithium replenishment; secondly, through a plurality of spray needles arranged at intervals along the width direction of the pole piece 4. The pole pieces are supplemented with lithium, and the injection needle 4 makes the injection range and injection speed more accurate, which can improve the uniformity of lithium supplementation, and can be applied to the pre-lithium of different battery models by adjusting the number of injection needles 4.

In order to easily adjust the supply speed of the lithium powder slurry and thus to control the thickness of the coating layer of the lithium powder slurry, in this embodiment, the slurry pump is a variable frequency pump.

In order to further precisely control the injection flow rate of the injection needle 4, so as to facilitate the control of the thickness of the coating layer of the lithium powder slurry and to make the pre-lithium uniform, in this embodiment, a flow meter is provided on the pipeline between the variable frequency pump and each injection needle 4 .

Referring to FIG. 2 , in order to prevent lithium powder from sticking to the foils on both sides of the pole piece, in this embodiment, two limit baffles 7 and adjustment fixing components are also included. The axial interval is arranged on the side of the electrostatic collection roller 3 facing the pole piece, the two limit baffles 7 are slidingly matched with the electrostatic collection roller 3, and the two limit baffles 7 and the electrostatic collection roller 3 are both provided with adjustment and fixing The adjusting and fixing components are used to move the corresponding limit plates along the axial direction of the electrostatic collecting roller 3 , and a space for the pole pieces to pass through is formed between the two limit baffles 7 . Moreover, the position between the two limiting baffles 7 can be adjusted for pole pieces of different widths by adjusting the fixing assembly.

In order to easily adjust the positions of the two limit baffles 7, so as to be suitable for pole pieces of different widths, and to avoid lithium powder sticking to the foils on both sides of the pole pieces, in this embodiment, the adjustment and fixing components include a roller frame and two locks. Tighten the fixing parts, the electrostatic collecting roller 3 is rotatably arranged on the roller frame, the roller frame is provided with a guide rod parallel to the axis of the electrostatic collecting roller 3, and the two limit baffles 7 are respectively fixed on the guide rod by locking the fixing parts , the connection between the limit baffle 7 and the guide rod can be adjusted along the length of the guide rod.

Specifically, the locking and fixing member is a clamp.

In order to supplement lithium on both sides of the pole piece, in this embodiment, there are two electrostatic lithium supplementing devices, the two electrostatic lithium supplementing devices are arranged at intervals along the conveying direction of the pole piece, and the two electrostatic lithium supplementing devices are respectively used for Lithium is supplemented on both sides of the pole piece.

In order to volatilize the solvent in the lithium powder slurry on the pole piece without affecting the subsequent steps and ensure the uniformity of the pre-lithium, in this embodiment, two drying mechanisms 5 are also included, and the two drying mechanisms 5 are in one-to-one correspondence. The ground is arranged downstream of the two electrostatic lithium replenishment mechanisms.

In a further embodiment, the drying mechanism 5 is a hot air drying mechanism. The hot air drying mechanism can further soften the lithium powder while ensuring that the solvent on the pole piece is completely volatilized, so that the lithium powder in the rolling process can crush the surface of the lithium powder to complete the activation, and contact the negative piece more closely to complete the pre-lithium without destroying the pole piece. surface of the sheet.

In order to ensure the continuity of lithium supplementation, in this embodiment, it also includes an unwinding mechanism 1, a rolling mechanism 6 and a winding mechanism 2, an unwinding mechanism 1, an electrostatic lithium replenishing mechanism, a drying mechanism 5, an electrostatic lithium replenishing mechanism, The drying mechanism 5 , the rolling mechanism 6 and the winding mechanism 2 are arranged at intervals along the conveying direction of the pole piece.

The pole piece is unwound by the unwinding mechanism. First, the pre-lithium is sprayed through the electrostatic lithium replenishing mechanism on one side of the pole piece, and then dried by the drying mechanism 5. After the electrostatic lithium replenishing mechanism on the other side of the pole piece, the pre-lithium is sprayed. After drying by the drying mechanism 5, the metal lithium powder is activated by the method of compound rolling, and finally is wound by the winding mechanism to complete the pre-lithiation of the negative pole piece.

Of course, in this embodiment, the tension of the pole piece and the pole piece buffer mechanism for adjusting the operation of the pole piece between the various mechanisms are also included.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (9)

1. a negative pole piece lithium powder supplementing lithium device, it is characterized in that, comprise electrostatic supplementary lithium mechanism, and static electricity supplementary lithium mechanism comprises static electricity generating assembly, a plurality of jet needles (4), slurry pump, electrostatic collecting roller (3) and lithium powder slurry supply components; The electrostatic collecting roller (3) and the spraying assembly are oppositely arranged and located on both sides of the pole piece conveying direction, the electrostatic collecting roller (3) is grounded, and the static electricity generating assembly is used to negatively charge the lithium powder sprayed by the spraying needle (4) to the pole piece ; The jetting assembly includes a plurality of jetting needle tubes (4), the plurality of jetting needle tubes (4) are arranged at intervals along the width direction of the pole piece, and the plurality of jetting needle tubes (4) are vertically directed to the pole piece, a lithium powder slurry supply assembly and a slurry pump The slurry pump is communicated with the plurality of injection needle tubes (4) through the pipeline respectively. 2 . The device for supplementing lithium with lithium powder of a negative electrode pole piece according to claim 1 , wherein the slurry pump is a variable frequency pump. 3 . 3 . The lithium powder supplementing device for the negative pole piece according to claim 2 , wherein a flow meter is provided on the pipeline between the variable frequency pump and each injection needle tube ( 4 ). 4 . 4. The device for replenishing lithium with negative pole piece lithium powder according to claim 1, characterized in that it further comprises two limit baffles (7) and an adjustment and fixing assembly, and the two limit baffles (7) collect along the static electricity The axial interval of the roller (3) is arranged on the side of the electrostatic collecting roller (3) facing the pole piece, the two limit baffles (7) and the electrostatic collecting roller (3) are slidably matched, and the two limit baffles (7) ) and the electrostatic collecting roller (3) are provided with an adjusting and fixing assembly, which is used to make the corresponding limit plate move along the axial direction of the electrostatic collecting roller (3). A space for the passage of the pole pieces is formed between them. 5. The lithium powder supplementing device for negative pole piece according to claim 4, characterized in that, the adjusting and fixing assembly comprises a roller frame and two locking fixing parts, and the electrostatic collecting roller (3) is rotatably arranged on the roller frame, and the roller The frame is provided with a guide rod parallel to the axis of the electrostatic collecting roller (3). The connection can be adjusted along the length of the guide rod. 6. The negative electrode pole piece lithium powder lithium supplementing device according to any one of claims 1-5, wherein the number of electrostatic lithium supplementing devices is two, and the two electrostatic lithium supplementing devices are arranged at intervals along the conveying direction of the pole piece, Two electrostatic lithium replenishment devices are respectively used to replenish lithium on both sides of the pole piece. 7. The device for supplementing lithium with negative pole piece lithium powder according to claim 6, characterized in that it further comprises two drying mechanisms (5), and the two drying mechanisms (5) are arranged one-to-one corresponding to two electrostatic lithium supplements downstream of the institution. 8 . The lithium powder supplementing device for the negative electrode pole piece according to claim 7 , wherein the drying mechanism ( 5 ) is a hot air drying mechanism. 9 . 9. The device for replenishing lithium with negative pole piece lithium powder according to claim 7 or 8, characterized in that it also comprises an unwinding mechanism (1), a rolling mechanism (6) and a winding mechanism (2), and the unwinding mechanism (1) The electrostatic lithium replenishing mechanism, the drying mechanism (5), the electrostatic lithium replenishing mechanism, the drying mechanism (5), the rolling mechanism (6) and the winding mechanism (2) are arranged at intervals along the conveying direction of the pole piece.

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