CN115411345A

CN115411345A - Battery core manufacturing method and lithium battery manufacturing method

Info

Publication number: CN115411345A
Application number: CN202211073651.4A
Authority: CN
Inventors: 张传祥; 余连文
Original assignee: Chongqing Talent New Energy Co Ltd
Current assignee: Chongqing Talent New Energy Co Ltd
Priority date: 2022-09-02
Filing date: 2022-09-02
Publication date: 2022-11-29

Abstract

The invention relates to a method for manufacturing a battery cell and a method for manufacturing a lithium battery. The cell manufacturing method comprises the following steps: s1, injecting electrolyte on at least one of a diaphragm, a positive plate and a negative plate while winding or laminating the positive plate, the diaphragm and the negative plate so as to infiltrate the at least one of the diaphragm, the positive plate and the negative plate; and step S2, packaging the battery cell obtained after winding or lamination is finished. In the method for manufacturing the battery cell, the winding or lamination, the liquid injection and the encapsulation are integrated, and the electrolyte infiltration process is started from the winding or lamination process, so that the whole battery cell can uniformly and fully infiltrate the electrolyte, the standing time can be greatly reduced, the using amount of the electrolyte is reduced, the manufacturing process is reduced, the production efficiency can be improved, and the cost can be saved.

Description

Battery core manufacturing method and lithium battery manufacturing method

Technical Field

The invention relates to the field of lithium ion batteries, in particular to a battery core manufacturing method and a lithium battery manufacturing method.

Background

Lithium batteries are widely used in various industries due to their characteristics of high energy density, safety, mature technology, etc. However, in the preparation process of the battery, in order to enable the electrolyte to sufficiently infiltrate the positive electrode plate, the negative electrode plate and the diaphragm, a long waiting time is often needed, and the production efficiency of the battery is seriously affected. On the other hand, when the electrolyte is not sufficiently soaked, the interfacial resistance of the battery may be increased, and the rate performance, the discharge capacity and the service life of the lithium battery are affected.

Although there are techniques of spraying a part of the electrolyte on the pole piece before winding or laminating the pole piece or dropping the electrolyte on the separator in advance before packaging, these techniques additionally add a spraying or dropping process, and the production efficiency is not high, so that further improvement and enhancement are required.

Disclosure of Invention

Problems to be solved by the invention

As described above, insufficient electrolyte infiltration may affect the performance and even the service life of the battery, and in order to sufficiently infiltrate the electrolyte, the electrolyte is often left for a long time or a spraying or dropping process is additionally added, so that the production time or production process of the battery cell is increased, the production efficiency is low, and more storage space is occupied when the battery cell is left for a long time.

Means for solving the problems

In order to reduce the time for soaking the battery, improve the production efficiency and simultaneously improve the wettability of the electrolyte in the battery cell under the conditions of effectively reducing the using amount of the electrolyte and saving the production cost, the invention provides a winding or laminating, liquid injection and packaging integrated battery cell manufacturing method, wherein at least part of the electrolyte is injected in the winding and laminating stages to wet the battery cell in advance, so that the electrolyte fully soaks the whole battery cell, the time required by the subsequent battery cell soaking can be greatly reduced, and even the standing process can be omitted. The injection, the winding and the lamination processes are carried out simultaneously, and the standing time is saved, so the production efficiency can be greatly improved.

Specifically, the invention provides a method for manufacturing a battery cell, which comprises the following steps:

s1, injecting electrolyte on at least one of a diaphragm, a positive plate and a negative plate while winding or laminating the positive plate, the diaphragm and the negative plate so as to infiltrate the at least one of the diaphragm, the positive plate and the negative plate; and

and S2, packaging the battery cell obtained after winding or lamination is finished.

According to the above battery cell manufacturing method, in the step S1, the electrolyte is injected in a continuous injection manner and/or a batch injection manner.

The cell manufacturing method comprises the following steps of: the distance between the upper edge and the lower edge of the positive and negative pole pieces or the diaphragms is 0.3-2 mm, preferably 0.5-1.5 mm, and the distance between the left edge and the right edge of the positive and negative pole pieces or the diaphragms is 2-6 mm, preferably 3-5 mm.

According to the above-mentioned method for manufacturing a battery cell, in the step S1, the electrolyte is injected in the manner of intermittent injection; in the intermittent liquid injection, a plurality of sub-injection regions are formed, and the interval between the adjacent sub-injection regions is 1mm or more, preferably 2mm or more.

According to the above battery cell manufacturing method, in the step S1, when the electrolyte is injected while winding, the injection is performed by spraying through a nozzle or dropping through a dropping device, and during the spraying or dropping, the nozzle or the dropping device is not moved, and the pole piece and the diaphragm move through a belt.

According to the above-mentioned cell manufacturing method, the pole piece near the winding needle side is a first pole piece, the pole piece far from the winding needle side and near the horizontal line side is a second pole piece, and the diaphragm is located between the first pole piece and the second pole piece; the number of the spray heads or the dripping devices is more than 1, and more than 1 spray head or dripping device is positioned at any position selected from a first position between the first pole piece and the winding needle, a second position between the first pole piece and the diaphragm, a third position between the second pole piece and the diaphragm and a fourth position between the second pole piece and a horizontal line;

wherein the first pole piece is selected from one of a positive pole piece and a negative pole piece; the second pole piece is selected from the other of the positive pole piece and the negative pole piece.

According to the above battery cell manufacturing method, the spray head or the dropping device is arranged at the second position and the third position, and is used for spraying the electrolyte onto the pole piece and the diaphragm; or,

the first position and the third position are provided with the spray heads or the dripping devices for spraying electrolyte on the pole pieces and the diaphragms; or,

and the second position and the fourth position are provided with the spray head or the dripping device for spraying electrolyte on the pole piece and the diaphragm.

According to the above cell manufacturing method, an included angle between the spraying direction of the nozzle in the first position and the pole piece is 5-90 degrees, preferably 30-60 degrees;

the included angles between the spraying directions of the spray heads in the second position and the third position and the pole piece or the diaphragm are 5-175 degrees, preferably 30-120 degrees;

the included angle between the spraying direction of the nozzle in the fourth position and the pole piece is 5-90 degrees, and preferably 30-60 degrees.

According to the above battery cell manufacturing method, in the step S1, when the lamination is performed and the electrolyte is injected, the injection is performed by spraying through a nozzle or dropping through a dropping device, and during the spraying or dropping, the nozzle or the dropping device moves, and the pole piece and the diaphragm are not moved.

According to the above-mentioned method for manufacturing a battery cell, the nozzles or the dropping devices are located above the pole pieces or the diaphragms, the angle between the spraying direction of the nozzles and the pole pieces or the diaphragms is 30-150 degrees, preferably 60-120 degrees, and the number of the nozzles or the dropping devices is more than 1.

The battery cell manufacturing method according to the above, wherein when the amount of electrolyte injected in step S1 is L, L is less than or equal to the final injection amount.

The battery cell manufacturing method according to the above, wherein when L is smaller than the final electrolyte injection amount, the battery cell manufacturing method further includes step S3: and carrying out secondary liquid injection on the packaged battery cell to achieve the final liquid injection amount.

According to the above-mentioned battery cell manufacturing method, when there are more than 1 spray heads or dropping devices, the spraying amount of each spray head or the dropping amount of each dropping device is the same or different, and the total spraying amount of all spray heads or the total dropping amount of all dropping devices is L.

According to the above-described battery cell manufacturing method, when the electrolyte is injected while winding, the spraying rate or the dropping rate of the electrolyte is the spraying amount of the electrolyte per nozzle or the dropping amount of the electrolyte per dropping device divided by the winding completion time.

According to the above-described battery cell manufacturing method, when the electrolyte is injected while the lamination is performed, the spraying rate or the dropping rate of the electrolyte is the amount of the electrolyte injected in each layer divided by the time of a single movement of the shower head or the dropping device.

Further, the invention also provides a manufacturing method of the lithium battery, which comprises the following steps:

manufacturing the battery cell by the manufacturing method; and

and (3) optionally standing the battery core, and then carrying out formation and capacity division to obtain the lithium battery.

ADVANTAGEOUS EFFECTS OF INVENTION

The technical scheme of the invention has the following beneficial effects.

(1) In the cell manufacturing method, at least part of electrolyte is injected in advance in the winding or lamination process, and the injected electrolyte can be uniformly distributed in the whole naked cell, so that the cell can be uniformly and fully soaked with the electrolyte.

(2) The electrolyte infiltration process is started from the winding or lamination process, so that the electrolyte infiltration process is always performed from the winding or lamination process to the liquid injection process, the standing process can be omitted, the cell preparation time is shortened, and the production efficiency is improved.

(3) The traditional electrolyte injection method generally needs to inject excessive electrolyte to enable the electrolyte to fully infiltrate the pole piece and the diaphragm.

(4) In the cell manufacturing method, the winding or lamination, the liquid injection and the packaging are integrated, so that the manufacturing procedures are reduced, the time can be saved, and the production efficiency can be improved.

Drawings

FIG. 1 shows a flow chart of the electrode wetting method of the present invention.

Fig. 2 is a schematic view showing an electrolyte injection region in the case of continuous injection of electrolyte.

Fig. 3 is a schematic view showing an electrolyte injection region in the case of intermittently injecting the electrolyte.

Fig. 4 is a schematic view showing an example of the position of the head and the winding in the winding process in the present invention.

Detailed Description

The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining different embodiments and technical means disclosed in the embodiments are also included in the technical scope of the present invention. All documents described in this specification are incorporated herein by reference.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

In the present specification, the numerical range represented by "numerical value a to numerical value B" means a range including an end point numerical value A, B.

In the present specification, "plural" in "plural", and the like means a numerical value of 2 or more unless otherwise specified.

In this specification, the terms "substantially", "substantially" or "substantially" mean an error of less than 5%, or less than 3%, or less than 1% as compared to the relevant perfect or theoretical standard.

In the present specification, "%" denotes mass% unless otherwise specified.

In the present specification, if "room temperature" or "normal temperature" is mentioned, the temperature may be generally 10 to 37 ℃ or 15 to 35 ℃.

In the present specification, the meaning of "may" or "may" includes both the meaning of the presence or absence of both the aspect and the aspect of performing a certain treatment and the aspect of not performing a certain treatment.

In this specification, "optional" and "optionally" mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

The terms "comprises" and "comprising," and any variations thereof, in the description and claims of this invention and the above-described drawings are intended to cover non-exclusive inclusions. For example, a process, method, or system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

In the present specification, reference to "some/preferred embodiments", "embodiments", and the like, means that a particular element (e.g., feature, structure, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

< first aspect >

The invention provides a method for manufacturing a winding or laminating, liquid injection and packaging integrated battery cell. As shown in fig. 1, the method for manufacturing a battery cell of the present invention includes:

In some embodiments of the present invention, the split pole pieces may be dried before winding or laminating the pole pieces so that the moisture content of the pole pieces meets the process requirements.

The injection method and injection region of the present invention will be described below.

In the present invention, the method of injecting the electrolyte in step S1 includes continuous injection and/or intermittent injection. The continuous liquid injection is continuous and uninterrupted liquid injection in the liquid injection area, and the intermittent liquid injection is performed at regular intervals in the liquid injection area.

Fig. 2 shows a schematic view of the liquid injection region in the continuous liquid injection method, and fig. 3 shows a schematic view of the liquid injection region in the intermittent liquid injection method. Fig. 2 and 3 each show an example in which an electrolyte is injected into an active material coating on a current collector of a pole piece. The upper, lower, left and right in fig. 2 and 3 are merely for convenience in describing the position of the pole piece or diaphragm and do not refer to a specific orientation.

In the continuous liquid injection method, liquid is injected on the pole piece and/or the diaphragm uninterruptedly. In order to prevent the electrolyte from overflowing the pole piece to cause unmeasurable loss, the injection area of the electrolyte on the pole piece or the diaphragm needs to be controlled. Specifically, the area where the electrolyte is injected on the pole piece and/or the diaphragm is: a region which is 0.3 to 2mm, preferably 0.5 to 1.5mm from the upper and lower edges of the pole piece or the diaphragm, and 2 to 6mm, preferably 3 to 5mm from the left and right edges of the pole piece or the diaphragm.

Specifically, the distance of the electrolyte injection region from the upper and lower edges of the pole piece or the separator may be 0.3mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, or the like. The distance of the electrolyte injection area from the left and right edges of the pole piece or the diaphragm may be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, etc.

In compartmentalized injection, a plurality of sub-injection zones (e.g., injection zones as shown in fig. 3) are formed on the membrane and/or the pole piece. The sub-infusion region shown in fig. 3 is rectangular, but the present invention is not limited thereto. For example, the shape of the sub-injection regions may also be square, grid, circle, hexagon, or the like, or may even be irregular such as wave, and the intervals between adjacent sub-injection regions may be the same or different, preferably the intervals are the same.

The interval between adjacent sub-infusion regions, that is, the distance between the sides of adjacent sub-infusion regions that face each other (e.g., the interval shown in fig. 3), may be 1mm or more, preferably 2mm or more, and more preferably 3mm or more. For example, the interval may be 1 to 5mm, specifically 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm. When the sub-injection regions are in a shape such as a circle or a wave, the interval between the adjacent sub-injection regions is the shortest distance among the distances between the sides facing each other. The area of each sub-infusion region is not particularly limited, and can be designed according to specific battery cells. And, the area of each sub-infusion region may be the same or different.

In the intermittent liquid injection, the distance between the electrolyte and the upper edge, the lower edge, the left edge and the right edge of the pole piece or the diaphragm is the same as that in the continuous liquid injection mode.

When the intermittent liquid injection mode is used for the condition that the injection amount of the electrolyte is small, the uniformity of the electrolyte is easy to control, and when the intermittent liquid injection mode is used for the large amount of the electrolyte, the interval area can contain the flowing electrolyte to prevent overflow.

In the present invention, in order to prevent the electrolyte from being injected outside the pole piece or the separator, it is necessary to identify and determine the injection region. Before electrolyte is injected or in the electrolyte injection process, a coating area of an active material of the pole piece can be identified through CCD visual detection equipment, the area of injected electrolyte is judged, then a control system can adjust the area of injected electrolyte according to information fed back by the CCD visual detection equipment, and the electrolyte is prevented from being injected outside the pole piece.

In the present invention, when the amount of electrolyte injected in step S1 is L, L may be less than or equal to the final injection amount. When L is equal to the final liquid injection amount, the secondary liquid injection step after encapsulation will not be required, and the standing step can be omitted.

When L is smaller than the final injection amount, the method for manufacturing a battery cell of the present invention further includes step S3: and carrying out secondary liquid injection on the packaged battery cell to achieve the final liquid injection amount. After the secondary injection, a standing may be optionally performed.

Step S1

In some embodiments of the present invention, the step S1 is performed while the winding is performed while the electrolyte is injected.

Specifically, the electrolyte is injected on at least one of the separator, the positive electrode sheet, and the negative electrode sheet while the separator or the positive and negative electrode sheets are wound up to the last layer, and then the injection is finished. The electrolyte may be injected when each layer of the separator or the positive and negative electrode sheets is wound, or may be optionally injected to some of the layers. In order to achieve a better wetting effect, it is preferable to inject the electrolyte into each layer.

In the case of injecting the electrolyte while winding, the injection of the electrolyte may be performed by spraying through a spray head or by dropping through a dropping device. When spraying or dripping, the spray head or the dripping device is not moved, and the pole piece and the diaphragm move through the belt.

In the present invention, the nozzle or the dropping device is not particularly limited, and a general nozzle for spraying a liquid or a general dropping device for dropping a liquid may be used as long as the spraying rate or the dropping rate can be controlled.

In the present invention, the number of the heads or the dropping devices is 1 or more. For example, the number of the spray heads or the dropping device may be 1 to 8, preferably 1 to 5. Specifically, 1, 2, 3, 4, 5, 6, 7, 8, etc. may be provided, respectively.

In the invention, the pole piece close to the winding needle side is called a first pole piece, the pole piece far away from the winding needle side and close to the horizontal line side is called a second pole piece, and the diaphragm is positioned between the first pole piece and the second pole piece. Wherein, the first pole piece is selected from one of a positive pole piece and a negative pole piece; the second pole piece is selected from the other of the positive pole piece and the negative pole piece.

In the present invention, a position between the first pole piece and the winding needle is referred to as a first position, a position between the first pole piece and the diaphragm is referred to as a second position, a position between the second pole piece and the diaphragm is referred to as a third position, and a position between the second pole piece and a horizontal line is referred to as a fourth position. More than 1 shower head or dropping device may be located at any position selected from the first position, the second position, the third position and the fourth position. That is, the position of the head or the dropping device may be at any one position, any two positions, any three positions, or at all four positions among the first to fourth positions.

In some preferred embodiments of the present invention, a spray head or a dropping device is provided in the second position and the third position for spraying the electrolyte onto the pole piece and the separator; or the first position and the third position are provided with spray heads or dripping devices for spraying the electrolyte on the pole pieces and the diaphragms; or the second position and the fourth position are provided with spray heads or dripping devices for spraying the electrolyte onto the pole pieces and the diaphragms.

Fig. 4 is a schematic diagram showing an example of the position of the head and the winding in the winding process. As shown in fig. 4, a head 1 for injecting an electrolyte is provided at a position (i.e., a first position) between a pole piece 1 (i.e., a first pole piece) and a winding needle, and a head 2 for injecting an electrolyte is provided at a position (i.e., a third position) between a pole piece 2 (i.e., a second pole piece) and a separator.

Although the head 1 is shown in the first position and the head 2 is shown in the third position in fig. 4, as described above, a head or a dropping device may be provided in the second position and the fourth position. In addition, although a specific place of the head is shown in fig. 4 as being located at the lower portion of the pole piece, specific places of the head and the dropping device in the first to fourth positions are not particularly limited as long as they are in the liquid injection region.

In fig. 4, 1 head 1 and 1 head 2 are shown, but as described above, the number of the heads or the dropping devices of the present invention may be 1 or more. In order to be compatible with wider pole pieces, the number of the spray heads can be increased in the width direction of the pole pieces so as to ensure that the electrolyte can be uniformly injected into the whole pole piece. The electrolyte has fluidity, so that the whole pole piece can be soaked.

The spray head 2 is shown facing the pole piece 2 in fig. 4, but the spray head 2 may also face the diaphragm. When a plurality of spray heads are present in the second position and the third position, their spraying or dropping directions may be the same or different. That is, the second and third position spray heads or drip devices may spray or drip the electrolyte to one or both of the pole piece and the separator. The electrolyte is preferably sprayed or dripped on the pole piece, because the pole piece coating is rough, the electrolyte can permeate into active substances, and the electrolyte is not easy to flow out of the pole piece during spraying or dripping.

As shown in fig. 4, when winding the pole piece, the included angles a, b, and c in the horizontal direction of the pole piece 1, the separator, and the pole piece 2 and the winding needle may be respectively changed from 0 ° to 180 ° as the winding proceeds.

When the dropping is performed by using the dropping device, the angle between the dropping direction of the dropping device and the horizontal line is 90 ° at any position from the first position to the fourth position.

In the invention, the included angle between the injection direction of the nozzle in the first position and the pole piece 1 can be 5-90 degrees, preferably 30-60 degrees, and more preferably 35-45 degrees. Specifically, the included angle may be 5 °, 10 °, 20 °, 30 °, 35 °, 40 °, 45 °, 50 °, 60 °, 70 °, 80 °, 90 °, and so on. The included angles between the injection directions of the nozzles in the second position and the third position and the pole piece or the diaphragm can be respectively 5-175 degrees, preferably 30-120 degrees, more preferably 30-60 degrees, and still more preferably 35-45 degrees. Specifically, the included angles may be 5 °, 20 °, 30 °, 35 °, 40 °, 45 °, 50 °, 60 °, 70 °, 80 °, 90 °, 120 °, 150 °, 175 °, and the like, respectively. The included angle between the injection direction of the nozzle in the fourth position and the pole piece can be 5-90 degrees, preferably 30-60 degrees, more preferably 35-45 degrees, and specifically can be 5 degrees, 10 degrees, 20 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees and the like.

In the present invention, in the case where the electrolyte is injected while winding is performed, when there are more than 1 head or dropping device, the spraying amount of each head or the dropping amount of each dropping device may be the same or different as long as the total spraying amount of all heads or the total dropping amount of all dropping devices is controlled to be L. The electrolyte spraying rate or the dripping rate is the electrolyte spraying amount of each spray head or the electrolyte dripping amount of each dripping device divided by the winding completion time, wherein the winding completion time refers to the time required for completing winding of the pole piece. The time for completion of winding is usually 1 to 15 seconds, preferably 3 to 10 seconds, and more preferably 5 to 8 seconds.

For example, when the total number of the heads or the dropping devices is m and the spraying amount of each head or the dropping amount of each dropping device is the same, the spraying amount of the electrolyte of each head or the dropping amount of each dropping device is L/m, which is the amount L of the electrolyte to be injected in step S1 divided by the number m of the heads. When the spraying amount of each head or the dropping amount of each dropping device is different, calculation is required according to the specific spraying amount or dropping amount.

In the invention, the speed of the traveling of the pole piece or the diaphragm is not particularly limited and can be adjusted according to actual needs. The belt speed is usually 0.01 to 1m/s, preferably 0.2 to 0.8m/s.

In other embodiments of the present invention, the step S1 is performed while the lamination is performed while injecting the electrolyte.

Specifically, the electrolyte is injected into at least one of the diaphragm, the positive plate and the negative plate while the diaphragm or the positive and negative plate is laminated until the last layer, and then the liquid injection is finished. The electrolyte may be injected in each of the separator, the positive electrode sheet, and the negative electrode sheet stacked one on another, or some of the layers may be optionally injected with the electrolyte. In order to achieve a better wetting effect, it is preferable to inject the electrolyte into each layer.

In the case of injecting the electrolyte while performing lamination, the injection of the electrolyte may be performed by spraying through a spray head or by dropping through a dropping device. When spraying or dripping, the nozzle or the dripping device moves, and the pole piece and the diaphragm are not moved. As mentioned above, the electrolyte is preferably injected into the electrode sheet because the coating of the electrode sheet is rough, the electrolyte can permeate into the active material, and the electrolyte is not easy to flow out of the electrode sheet during spraying.

In the present invention, the head or the dropping device is not particularly limited, and a general head for spraying a liquid or a general dropping device for dropping a liquid may be used as long as the spraying rate or the dropping rate can be controlled.

In the case of laminating while injecting the electrolyte, the nozzle or the dropping device is located above the pole piece or the separator, and the angle between the injection direction of the nozzle and the pole piece or the separator is 30 to 150 ℃, preferably 60 to 120 ℃, for example, 30 to 150 °, preferably 60 to 120 °, and more preferably 80 to 100 °. In particular, the angle may be 30 °, 45 °, 60 °, 70 °, 80 °, 90 °, 100 °, 110 °, 120 °, 135 °, 150 °, etc. The angle between the dripping direction of the dripping device and the pole piece or the diaphragm is 90 degrees. The number of the nozzles or the dropping devices is not particularly limited, and may be appropriately adjusted according to the width of the pole piece. In the present invention, the number of the heads or the dropping devices may be 1 or more, for example, 1 to 8, preferably 1 to 5. Specifically, the number of the heads or the dropping devices may be 1, 2, 3, 4, 5, 6, 7, 8, or the like.

In the case of injecting the electrolyte while performing lamination, the spraying rate or dropping rate of the electrolyte is the amount of the electrolyte injected in each layer into which the electrolyte is injected divided by the time of a single movement of the head or dropping device. When the total number of the layers of the pole piece and the diaphragm injected with the electrolyte is n and the injected electrolyte amount of each layer is the same, the required injected electrolyte amount of each layer is L/n which is obtained by dividing the required injected electrolyte amount L in the step S1 by the total number of the layers n. The spraying rate or dropping rate of the electrolyte is the amount of electrolyte injected in each layer L/n divided by the time the dropping device or nozzle is moved. When the amount of electrolyte injected per layer is different, it is necessary to perform calculation according to the specific amount of electrolyte injected per layer.

In the present invention, the "time of a single movement" means a time required for each layer to be sprayed or dropped by the spray head or the dropping device. In the present invention, the time of the single movement of the dropping device or the shower head is not particularly limited, and can be adjusted according to actual needs. The time for a single movement is generally from 0.01 to 1s, preferably from 0.05 to 0.8s, more preferably from 0.1 to 0.2s.

Step S2 and step S3

In step S2, the battery cell obtained after winding or laminating the pole pieces is packaged. Namely, put naked electric core into electric core shell to weld the battery apron.

Step S3 is an optional step. As described above, when the amount of electrolyte L injected in step S1 is smaller than the final injection amount, step S3 is required: and carrying out secondary liquid injection on the packaged battery cell to achieve the final liquid injection amount. When the amount of electrolyte L injected in step S1 is equal to the final injection amount, step S3 will not be required.

In the invention, the equipment for preparing the battery core has good sealing performance, the dew point of the equipment area is strictly controlled to be lower than minus 45 ℃, and inert gases such as nitrogen, argon and the like are filled into the equipment, so as to isolate moisture in the air and prevent the volatilization of the electrolyte.

< second aspect >

A second aspect of the present invention provides a method for manufacturing a lithium battery, including: manufacturing the battery cell by the manufacturing method; and a step of optionally allowing the battery cell to stand, and then carrying out formation and capacity division, thereby obtaining the lithium battery.

The cell produced and impregnated by the method of the present invention may be left alone, or may be left alone for a period of 4 hours or less, preferably 3 hours or less, and more preferably 1 hour or less, if a secondary injection is performed.

The standing time of the traditional battery cell after soaking needs 8-72 hours, but the standing time can be shortened to 0-4 hours in the invention, so that the time is greatly saved, and the production efficiency is improved.

The method and conditions for chemical composition and volume separation are not particularly limited, and those conventional in the art can be used.

In the present invention, the type of battery is not particularly limited, and may be, for example, a cylindrical type, a square case, a pouch type, or the like.

Examples

The present invention will be described in detail below by way of examples. The examples of embodiments are intended to be illustrative of the invention and are not to be construed as limiting the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

In the embodiments, the electrolyte is injected by spraying through a spray head. The following is a detailed description.

In the embodiment of the invention, the equipment for preparing the battery cell has good sealing performance, the dew point of a working area of the equipment is-45 ℃, and nitrogen is filled into the equipment to isolate air, so that the electrolyte is prevented from volatilizing.

Example 1: continuous liquid injection method

(1) Drying the split pole piece to reduce the water content to less than 300ppm;

(2) Before and during the electrolyte spraying process, identifying a pole piece coating area through CCD visual detection equipment and judging the electrolyte spraying area, and then adjusting the electrolyte spraying area by a control system according to information fed back by the CCD visual detection equipment to prevent the electrolyte from being sprayed out of the pole piece;

(3) During winding, 1 sprayer 1 and 1 sprayer 2 shown in fig. 4 are used for continuously injecting electrolyte into at least one of the diaphragm, the positive plate and the negative plate in the process of the pole piece moving, wherein the sprayer 1 and the sprayer 2 are respectively arranged at the first position and the third position, the included angles between the spraying directions of the sprayer 1 and the sprayer 2 and the diaphragm and/or the positive and negative plates are 90 degrees, and the electrolyte spraying amounts of the sprayer 1 and the sprayer 2 are the same. When the amount of the electrolyte injected in this stage is L, the amount of the electrolyte sprayed by each nozzle is L/2.

The region into which the electrolyte is injected is continuous. The distance between the electrolyte injection area and the upper edge and the lower edge of the pole piece or the diaphragm is 1.5mm, and the distance between the electrolyte injection area and the left edge and the right edge of the pole piece or the diaphragm is 1.5mm;

(4) The electrolyte spraying rate is the electrolyte spraying amount L/2 of each of the spray heads 1 and 2 divided by the winding completion time, and the winding completion time is 8s in the embodiment;

(5) Packaging the wound battery cell;

(6) If the amount L of the electrolyte injected in the winding stage is less than the injection amount required by design, the rest electrolyte needs to be injected again;

(7) And standing the prepared battery cell for less than 4 hours, and then carrying out formation and capacity grading, thereby completing the preparation of the lithium battery.

Example 2: continuous liquid injection method

(2) Before or during the electrolyte spraying process, the coating area of the pole piece can be identified by CCD visual detection equipment and the area of the sprayed electrolyte can be judged, and then the control system can adjust the area of the sprayed electrolyte according to the information fed back by the CCD visual detection equipment to prevent the electrolyte from being sprayed out of the pole piece;

(3) When laminating, every layer of pole piece or diaphragm is placed, 1 sprayer is used for injecting electrolyte into at least one of the diaphragm, the positive pole piece and the negative pole piece, wherein the included angle between the spraying direction of the sprayer and the diaphragm or the positive and negative pole pieces is 90 degrees. When the amount of electrolyte injected in this stage is L and the number of layers of injected electrolyte is n, the amount of electrolyte injected per layer is L/n. The region into which the electrolyte is injected is continuous. The distance between the electrolyte injection area and the upper edge and the lower edge of the pole piece or the diaphragm is 0.5mm, and the distance between the electrolyte injection area and the left edge and the right edge of the pole piece or the diaphragm is 0.5mm;

(4) The electrolyte spraying speed is the electrolyte amount L/n injected into each layer divided by the time of single movement of the spray head, and the time of single movement of the spray head in the embodiment is 0.15s;

(5) Packaging the laminated battery core;

(6) If the amount L of the electrolyte injected in the lamination stage is less than the injection amount required by design, the rest electrolyte needs to be injected again;

(7) And standing the prepared battery cell for less than 4 hours, forming, and grading to finish the preparation of the lithium battery.

Example 3: intermittent liquid injection mode

(1) Drying the split pole piece to reduce the water content to be less than 300ppm;

(2) Before or in the process of spraying the electrolyte, the coating area of the pole piece can be identified by CCD visual detection equipment and the area of the sprayed electrolyte can be judged, and then the control system can adjust the area of the sprayed electrolyte according to the information fed back by the CCD visual detection equipment to prevent the electrolyte from being sprayed outside the pole piece;

(3) During winding, electrolyte is injected into at least one of the diaphragm, the positive plate and the negative plate at intervals by using 1 sprayer 1 and 1 sprayer 2 shown in fig. 4 in the process of the pole piece moving, wherein the sprayers 1 and 2 are respectively arranged at the first position and the third position, the included angles between the spraying directions of the sprayers 1 and 2 and the diaphragm and/or the positive and negative plates are 90 degrees, and the spraying amounts of the electrolyte of the sprayers 1 and 2 are the same. When the amount of the electrolyte injected in this stage is L, the amount of the electrolyte sprayed by each nozzle is L/2.

The region into which the electrolyte was injected (i.e., the sub-injection region) was rectangular in shape, and the interval between adjacent sub-injection regions was 2.5mm. The width of each sub-infusion region can be controlled according to the design of the battery cell. The distance between the electrolyte injection area and the upper edge and the lower edge of the pole piece or the diaphragm is 1mm, and the distance between the electrolyte injection area and the left edge and the right edge of the pole piece or the diaphragm is 1mm;

(5) Packaging the wound battery cell;

(6) If the amount of the electrolyte injected in the winding stage is less than the injection amount required by design, the rest electrolyte needs to be injected again;

Example 4: intermittent liquid injection method

(3) When laminating, every layer of pole piece or diaphragm is placed, 1 sprayer is used for injecting electrolyte into at least one of the diaphragm, the positive pole piece and the negative pole piece, wherein the included angle between the spraying direction and the diaphragm and/or the positive and negative pole pieces is 90 degrees. When the amount of electrolyte injected in this stage is L and the number of layers of injected electrolyte is n, the amount of electrolyte injected per layer is L/n. The region (i.e., the sub-injection region) into which the electrolyte is injected is rectangular, and the interval between adjacent sub-injection regions is 3mm. The width of each sub-infusion area can be controlled according to the design of the battery cell. The distance between the electrolyte injection area and the upper edge and the lower edge of the pole piece or the diaphragm is 1.5mm, and the distance between the electrolyte injection area and the left edge and the right edge of the pole piece or the diaphragm is 1.5mm;

(5) Packaging the laminated battery core;

(6) If the amount of the electrolyte injected in the lamination stage is less than the injection amount required by design, the rest electrolyte needs to be injected again;

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or technical improvements to the market, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Industrial applicability

In the invention, the winding or lamination, the liquid injection and the packaging are integrated, so that the electrolyte infiltration process is started from the winding or lamination process, the whole battery core can uniformly and fully infiltrate the electrolyte, the standing time can be greatly reduced, the using amount of the electrolyte is reduced, the manufacturing process is reduced, the production efficiency can be improved, and the cost is saved.

Claims

1. A method for manufacturing a battery cell is characterized by comprising the following steps:

2. The battery cell manufacturing method according to claim 1, wherein in the step S1, the electrolyte is injected in a continuous injection manner and/or a spaced injection manner.

3. The cell manufacturing method according to claim 1 or 2, wherein the region where the electrolyte is injected on at least one of the separator, the positive electrode tab and the negative electrode tab is: the distance between the upper edge and the lower edge of the positive and negative pole pieces or the diaphragm is 0.3-2 mm, preferably 0.5-1.5 mm, and the distance between the left edge and the right edge of the positive and negative pole pieces or the diaphragm is 2-6 mm, preferably 3-5 mm.

4. The battery cell manufacturing method according to claim 2 or 3, wherein in the step S1, the electrolyte is injected in a manner of intermittent injection; in the intermittent liquid injection, a plurality of sub-injection regions are formed, and the interval between the adjacent sub-injection regions is 1mm or more, preferably 2mm or more.

5. The battery core manufacturing method of any one of claims 1 to 4, wherein in the step S1, when the electrolyte is injected while winding, the injection is spraying through a spray head or dropping through a dropping device, and when the spraying or dropping is performed, the spray head or the dropping device is not moved, and the pole piece and the diaphragm move through a belt.

6. The method for manufacturing the electrical core according to claim 5, wherein the pole piece close to the winding needle side is a first pole piece, the pole piece away from the winding needle side and close to the horizontal line side is a second pole piece, and the diaphragm is located between the first pole piece and the second pole piece; the number of the spray heads or the dripping devices is more than 1, and more than 1 spray head or dripping device is positioned at any position selected from a first position between the first pole piece and the winding needle, a second position between the first pole piece and the diaphragm, a third position between the second pole piece and the diaphragm and a fourth position between the second pole piece and a horizontal line;

7. The method for manufacturing the battery core according to claim 6, wherein the spray head or the dropping device is arranged in the second position and the third position and used for spraying the electrolyte onto the pole piece and the diaphragm; or,

8. The electrical core manufacturing method of claim 6 or 7, wherein an included angle between the spraying direction of the nozzle in the first position and the pole piece is 5-90 degrees, preferably 30-60 degrees;

9. The battery core manufacturing method according to any one of claims 1 to 4, wherein in the step S1, when the lamination is performed while the electrolyte is injected, the injection is spraying through a spray head or dropping through a dropping device, and during the spraying or dropping, the spray head or the dropping device moves, and the pole piece and the diaphragm are not moved.

10. The battery core manufacturing method of claim 9, wherein the nozzles or the dropping devices are located above the pole pieces or the diaphragms, an angle between the spraying direction of the nozzles and the pole pieces or the diaphragms is 30-150 degrees, preferably 60-120 degrees, and the number of the nozzles or the dropping devices is more than 1.

11. The battery cell manufacturing method according to any one of claims 5 to 10, wherein when the amount of electrolyte injected in step S1 is L, L is less than or equal to the final injection amount.

12. The cell manufacturing method according to claim 11, wherein when L is smaller than the final shot size, the cell manufacturing method further comprises step S3: and carrying out secondary liquid injection on the packaged battery cell to achieve the final liquid injection amount.

13. The battery core manufacturing method according to claim 11 or 12, wherein when more than 1 spray head or dripping device is present, the spraying amount of each spray head or the dripping amount of each dripping device is the same or different, and the total spraying amount of all spray heads or the total dripping amount of all dripping devices is L.

14. The method for manufacturing the battery cell of claim 13, wherein when the electrolyte is injected while winding, the spraying rate or the dropping rate of the electrolyte is the spraying amount of the electrolyte per nozzle or the dropping amount of the electrolyte per dropping device divided by the winding completion time.

15. The method for manufacturing the battery cell according to claim 11 or 12, wherein when the electrolyte is injected while the lamination is performed, the spraying rate or the dropping rate of the electrolyte is the amount of the electrolyte injected in each layer divided by the time of a single movement of the spray head or the dropping device.

16. A method of making a lithium battery, comprising:

fabricating a cell by the cell fabrication method of any of claims 1-15; and