WO2021218188A1

WO2021218188A1 - Manufacturing method for cell of energy storage apparatus, and cell

Info

Publication number: WO2021218188A1
Application number: PCT/CN2020/136754
Authority: WO
Inventors: 陈志勇
Original assignee: 广东微电新能源有限公司
Priority date: 2020-04-29
Filing date: 2020-12-16
Publication date: 2021-11-04
Also published as: CN111446480A

Abstract

Disclosed are a manufacturing method for a cell of an energy storage apparatus and a cell, the method comprising: sandwiching one of either a positive electrode plate or a negative electrode plate between two isolation membranes; arranging the other of the positive electrode plate or the negative electrode plate on the outer side of one of the isolation membranes; starting winding from the same end of the positive electrode plate, the negative electrode plate and the two isolation membranes and onto a winding spindle to form a spiral-shaped winding structure; at least one of the isolation membranes has an extension portion that protrudes from an end of the positive electrode plate and an end of the negative electrode plate, the extension portion being fixed on the side wall of the winding structure; and retracting the spindle from the winding structure so as to form a through hole in the middle part of the winding structure. In an embodiment of the present invention, an electric connecting part is welded to a housing body in the space inside the through hole. An excessively long electric connecting part is not required, avoiding the problem of a bent electric connecting part affecting the safety of the energy storage apparatus.

Description

Method for preparing battery of energy storage device and battery

Technical field

The present invention relates to the technical field of energy storage, and more specifically, to a method for preparing a battery core of an energy storage device and a battery core.

Background technique

Existing energy storage equipment generally includes a casing and a battery core arranged inside the casing. In the case of installing the battery core inside the casing, it is necessary to weld the electrical connection part on the battery core to the casing. Welding the electrical connection at the bottom requires that the electrical connection is set to be longer than the length of the casing, and when the battery core is placed outside the casing, the electrical connection and the casing are welded together. Putting the battery core into the shell will cause the welded electrical connection to bend, which will affect the structural strength of the electrical connection, and cause the problem of conduction and short-circuit between the bent part of the electrical connection and other structures. . As a result, in the energy storage device of the prior art, there is a problem that the electrical connection part is bent, which affects the safety of the energy storage device.

Therefore, it is necessary to provide a new technical solution to solve the above technical problems.

Summary of the invention

An object of the present invention is to provide a new technical solution for the preparation method of the battery cell of the energy storage device.

According to the first aspect of the present invention, there is provided a method for manufacturing a battery cell of an energy storage device,

Clamp either the positive electrode sheet or the negative electrode sheet between the two separators;

Disposing the other of the positive electrode sheet and the negative electrode sheet on the outside of one of the isolation membranes;

Start winding from the same end of the positive electrode sheet, the negative electrode sheet and the two separators, and wind them on the winding needle to form a spiral winding structure;

At least one of the isolation membranes has an extension part protruding from the end of the positive electrode sheet and the end of the negative electrode sheet, and the extension part is fixed on the side wall of the winding structure;

The winding needle is drawn away from the winding structure to form a through hole in the middle of the winding structure.

Optionally, along the axial direction of the winding structure, the size of the negative electrode sheet is greater than the size of the positive electrode sheet by at least 0.1 mm.

Optionally, along the axial direction of the winding structure, the sizes of the two isolation films are both greater than the size of the negative electrode sheet by at least 0.5 mm.

Optionally, along the axial direction of the winding structure, a part of the separator that is larger than the size of the negative electrode sheet forms protrusions at both ends of the winding structure, and the protrusions are tilted , To cover the positive electrode sheet and the negative electrode sheet at both ends.

Optionally, along the circumferential direction of the winding structure, the size of the negative electrode sheet is at least 3 mm larger than the size of the positive electrode sheet.

Optionally, the aperture of the through hole is 0.5 mm-3.0 mm.

Optionally, the positive electrode sheet and the negative electrode sheet are respectively provided with electrical connection portions, one of the electrical connection portions protruding from one end portion of the winding structure in the axial direction, and the other electrical connection portion Protruding from the other end portion of the winding structure, an insulating layer is provided between the electrical connection portion and the corresponding end portion.

Optionally, after the winding needle is drawn out, a cylindrical core is arranged in the through hole, and the cylindrical core has an inner hole.

Optionally, before winding the laminated structure along the winding needle, a cylindrical cylindrical core is sleeved on the winding needle.

Optionally, the winding needle has a cylindrical shape, an elliptical cylindrical shape, a prismatic shape or a rectangular parallelepiped shape.

Optionally, at least one of the two isolation films protrudes from the positive electrode sheet and the negative electrode sheet at the beginning of the winding structure.

According to a second aspect of the present invention, there is provided a battery cell of an energy storage device, comprising a positive electrode sheet, a negative electrode sheet and two separators, one of the positive electrode sheet and the negative electrode sheet is located between the two separators , The other is located outside one of the isolation films, the positive electrode sheet, the negative electrode sheet and the two isolation films form a spiral winding structure, and a through hole is formed in the middle of the winding structure.

According to an embodiment of the present disclosure, the electrical connection portion and the housing are welded through the space in the through hole, and there is no need to provide an excessively long electrical connection portion, which can avoid the problem that the electrical connection portion is bent and affects the safety of the energy storage device.

Through the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear.

Description of the drawings

The drawings incorporated in the specification and constituting a part of the specification illustrate the embodiments of the present invention, and together with the description are used to explain the principle of the present invention.

FIG. 1 is a schematic diagram of a structure before winding in a method for preparing a battery cell of an energy storage device in an embodiment of the present disclosure.

FIG. 2 is a schematic diagram of the end surface of the winding structure formed after the battery core of the energy storage device is wound in an embodiment of the present disclosure, and the winding structure is not drawn away from the winding needle.

Fig. 3 is a structural schematic diagram of the end surface of the winding structure of the cell after the winding needle is pulled out in an embodiment of the present disclosure.

Fig. 4 is a partial schematic diagram of the A-A sectional view in Fig. 3.

Fig. 5 is a structural schematic diagram of an energy storage device in an embodiment of the present disclosure with insulating tape wrapped around the battery core.

In the figure, 1 is a positive electrode sheet, 2 is a negative electrode sheet, 3 is a separator, 31 is an extension, 32 is a protrusion, 4 is a winding needle, 5 is a through hole, and 6 is an insulating tape.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless specifically stated otherwise, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation to the present invention and its application or use.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings.

In an embodiment of the present disclosure, there is provided a method for manufacturing a battery cell of an energy storage device,

Clip any one of the positive electrode sheet 1 or the negative electrode sheet 2 between the two separators 3;

Placing the other of the positive electrode sheet 1 and the negative electrode sheet 2 on the outside of one of the isolation films 3;

Start the winding from the same end of the positive electrode sheet 1, the negative electrode sheet 2 and the two isolation films 3, and wind it on the winding needle 4 to form a spiral winding structure;

At least one of the isolation films 3 has an extension portion 31 protruding from the end of the positive electrode sheet 1 and the end of the negative electrode sheet 2, and the extension portion 31 is fixed on the side wall of the winding structure;

The winding needle 4 is drawn away from the winding structure to form a through hole 5 in the middle of the winding structure.

In this embodiment, as shown in FIG. 1, the positive electrode sheet 1, the negative electrode sheet 2 and the separator 3 may be arranged in a laminated structure before winding, and then the winding may be performed. The end of the wound structure after winding has the structure shown in FIG. 2. As shown in Fig. 3, the through hole 5 is formed after the winding needle 4 is drawn out.

A through hole 5 is formed in the middle of the battery core of the energy storage device prepared by the preparation method. In the process of arranging the cell in the casing of the energy storage device, the cell is first placed in the casing, and the electrical connection part of the cell and the casing are welded through the through hole 5. The welding process may be to extend the welding position into the through hole 5 and move it along the through hole 5 to the welding target position of the electrical connection part and the housing for welding. This kind of cell structure and welding method does not need to have an excessively long electrical connection part, and an electrical connection part structure that fits the welding position can be directly set, and the electrical connection part will not bend after welding and other problems that affect the welding quality. The connection part is stronger, thereby avoiding the impact on the safety of the energy storage device.

In the process of welding the electrical connection part, the point bottom resistance welding can be used, and the single-pin resistance welding can be used, and the single-pin resistance welding is easier to extend into the through hole 5 for welding.

The extension part 31 is fixed on the side wall of the winding structure, which can protect the winding structure on the side wall, and avoid the positive electrode sheet 1 or the negative electrode sheet 2 on the side wall of the winding structure and the casing of the energy storage device. Pass. One isolation film 3 may extend out of the extension portion 31, or both isolation films 3 may extend out of the extension portion 31, and the extension portion 31 surrounds the side wall at least once.

In an example, the isolation film 3 may be an insulating material capable of passing lithium ions. Insulation is formed between the positive electrode sheet 1 and the negative electrode sheet 2, and insulation is formed between the winding structure and the case.

In an example, the two isolation films 3 may be formed by bending one isolation film 3. For example, after a part of the separator 3 is placed between the positive electrode sheet 1 and the negative electrode sheet 2, the other part is bent to the outside of the positive electrode sheet 1 or the negative electrode sheet 2. Thus, a structure in which the positive electrode sheet 1 or the negative electrode sheet 2 is sandwiched in the folded separator 3 is formed.

In one embodiment, along the axial direction of the winding structure, the size of the negative electrode sheet 2 is greater than the size of the positive electrode sheet 1 by at least 0.1 mm.

When the battery cell works in the energy storage device, the negative electrode material on the negative electrode sheet 2 and the positive electrode material on the positive electrode sheet 1 act to release or store electrical energy. In the axial direction of the winding structure, when the size of the negative electrode sheet 2 is greater than or equal to that of the positive electrode sheet 1, sufficient negative electrode material can be ensured to enable the positive electrode material to fully exert its charge and discharge capabilities, and the utilization rate of the positive electrode sheet 1 can be improved. The positive electrode material in the positive electrode sheet 1 is generally copper, and the negative electrode material in the negative electrode sheet 2 is generally aluminum, and the cost of the positive electrode sheet 1 is higher. The utilization rate of the positive electrode sheet 1 in the battery is improved, so that the material with a higher cost ratio in the battery is effectively used. Indirectly reduces the waste of battery cost. The size of the negative electrode sheet 2 is greater than the size of the positive electrode sheet 1 by at least 0.1 mm, which can satisfy the amount of the negative electrode sheet 2 required to fully utilize the positive electrode sheet 1.

For example, in the battery cell of an energy storage device, the positive electrode active material provided on the positive electrode sheet 1 is lithium. During the charging and discharging process of the battery cell of the energy storage device, the positive electrode sheet 1 releases lithium ions through the isolation membrane 3 to reach and embed in the negative electrode sheet 2. In this process, if the space on the negative electrode sheet 2 for receiving lithium ions is not enough, the problem of lithium ion accumulation will occur, which will cause the energy storage device to explode, and in severe cases, it will explode directly. In this embodiment, the size of the negative electrode sheet 2 is greater than the size of the positive electrode sheet 1 by at least 0.1 mm in the axial direction of the winding structure. It can provide enough space to receive lithium ions, and avoid the potential explosion hazard of the energy storage device caused by the accumulation of lithium ions.

In an example, along the axial direction of the winding structure, the size of the negative electrode sheet 2 is greater than the size of the positive electrode sheet 1 by 0.1 mm-0.5 mm.

Within this size difference, the negative electrode sheet 2 not only satisfies the full charge and discharge requirements of the positive electrode sheet 1, but also does not increase the volume of the negative electrode sheet 2 too much. Under the same energy density, the negative electrode sheet 2 avoids the excessive volume of the battery cell. The problem.

In one embodiment, along the circumferential direction of the winding structure, the size of the negative electrode sheet 2 is greater than the size of the positive electrode sheet 1 by at least 3 mm.

In this embodiment, similarly, the size of the negative electrode sheet 2 in the circumferential direction of the winding structure is greater than the size of the positive electrode sheet 1 by 3 mm or more to ensure that the positive electrode sheet 1 fully exerts its charge and discharge capabilities. The utilization rate of the positive electrode sheet 1 is improved, and the waste of the battery cell cost is reduced.

In one embodiment, along the axial direction of the winding structure, the sizes of the two isolation films 3 are both larger than the size of the negative electrode sheet 2 by at least 0.5 mm.

In this embodiment, the axial dimension of the separator 3 in the winding structure is larger than that of the negative electrode sheet 2, so that in the winding structure, the separator film 3 must be sandwiched between the positive electrode sheet 1 and the negative electrode sheet 2. In such a structure, a short circuit between the positive electrode sheet 1 and the negative electrode sheet 2 can be avoided, and the safety of the battery cell is improved. The size of the isolation film 3 is greater than the size of the negative electrode sheet 2 by at least 0.5 mm, which can effectively provide an insulation effect between the positive electrode sheet 1 and the negative electrode sheet 2.

In one embodiment, as shown in FIG. 4, along the axial direction of the winding structure, the part of the separator 3 larger than the size of the negative electrode sheet 2 is formed at both ends of the winding structure The protruding portion 32 is tilted to cover the positive electrode sheet 1 and the negative electrode sheet 2 at both ends.

In this embodiment, the protruding portion 32 is tilted to cover the positive electrode sheet 1 and the negative electrode sheet 2 at the end of the winding structure. The insulation performance of the end of the covered winding structure improves the safety performance of the battery core.

In an embodiment, the aperture of the through hole 5 is 0.5 mm-3.0 mm.

The through hole can facilitate the welding of the electrical connection part on the battery cell and the housing. The through hole 5 within the aperture range of this embodiment can meet the space requirement of the welding process without causing the battery core to occupy too much space.

In order to ensure that the size of the through hole 5 is within this range, the radial size of the winding needle can be set to 0.5 mm-3.0 mm. The size of the through hole 5 after winding can meet the range requirement in this embodiment.

In one embodiment, the positive electrode sheet 1 and the negative electrode sheet 2 are respectively provided with electrical connection parts, wherein one of the electrical connection parts protrudes from one end of the winding structure in the axial direction, and the other is The electrical connection portion protrudes from the other end portion of the winding structure, and an insulating layer is provided between the electrical connection portion and the corresponding end portion.

In this embodiment, an insulating layer is provided between the electrical connection portion and the corresponding end portion, which can prevent the electrical connection portion from contacting and conducting short circuits with different electrodes in the positive electrode sheet 1 and the negative electrode sheet 2, thereby improving the electrical connection. The safety of the core.

In one embodiment, after the winding needle 4 is drawn out, a cylindrical core is arranged in the through hole 5, and the cylindrical core has an inner hole.

In this embodiment, the cylindrical core column is arranged in the through hole 5 to support the through hole 5 in the middle of the winding structure, which can prevent the winding structure from loosening into the through hole after the winding needle 4 is drawn out, thereby improving The robustness of the winding structure. And in the process of welding the electric connection part on the electric core, the welding needle can be inserted through the inner hole of the cylindrical core column for welding, thereby avoiding the need to place the electric core in the shell for welding electric connection parts in the prior art. Outside the body, the electrical connection part is bent when the battery is put into the shell after the welding is completed.

In one embodiment, before winding the laminated structure along the winding needle 4, a cylindrical cylindrical core is sleeved on the winding needle 4.

In this embodiment, the cylindrical core column is sleeved on the winding needle 4 before the winding, and the winding needle only needs to be taken out after the winding is completed. In such a step, it is easier to leave the cylindrical core column in the through hole 5 in the middle of the winding structure, which saves the step of inserting the cylindrical core column after being drawn out.

In one embodiment, the winding needle 4 has a cylindrical shape, an elliptical cylindrical shape, a prismatic shape, or a rectangular parallelepiped shape. The function of the winding needle 4 includes winding the battery core, and the winding needle 4 can wind the battery core into a winding structure. In the shape of the winding needle 4 in this embodiment, all can be effectively wound to form a spiral winding structure, and the through hole 5 is formed after the winding needle 4 is drawn out. The shape of the winding needle 4 determines the shape of the wound winding structure. For example, the winding structure wound by a cylindrical winding needle is a cylinder.

In one example, the winding needle 4 can be made of tungsten steel material, which has high strength, and the prepared winding needle 4 will not deform during the winding process, which can avoid the deformation of the winding structure caused by the deformation of the winding needle. To ensure that the coaxiality of the battery core will not be reduced. In addition, the winding part of the winding needle 4 can be prepared to a diameter range of 0.5 mm-3.0 mm, so that the energy density of the battery core will not be affected under the condition that the formed through hole 5 meets the welding conditions.

The winding needle 4 can be set as a progressive stepped shaft structure, and the structure used for winding meets the size requirement, and the progressive stepped shaft can provide sufficient structural strength.

In one example, two winding needles 4 are used to wind the battery core to form a winding structure. The two winding needles 4 are arranged opposite to each other, the part of the winding needle 4 for winding the battery is set in a semi-cylindrical shape, and the semi-cylindrical shapes on the two winding needles 4 cooperate to form a cylindrical shape. After the winding is successful, the two winding needles 4 are pulled away from the two ends of the winding structure respectively, which can avoid the problem of the winding core being taken out caused by the single winding needle 4 being pulled away from one direction.

The ends of the two winding needles 4 can be formed with a chamfered surface, and the chamfered surface plays a guiding role in the process of the two winding needles 4 cooperate to form a cylindrical structure.

In one embodiment, at least one of the two isolation films 3 protrudes from the positive electrode sheet 1 and the negative electrode sheet 2 at the beginning of the winding structure. The starting end of the winding structure is located in the through hole 5 after the winding structure is formed, and the separator 3 protrudes from the positive electrode sheet 1 and the negative electrode sheet 2 at the beginning to form insulation at the beginning, avoiding the positive electrode sheet 1 and the negative electrode sheet in the through hole 5 The beginning of 2 is connected to other structures, which improves the safety of the battery cell.

In one embodiment, as shown in FIG. 5, an insulating adhesive paper 6 is fixed on the side wall of the winding structure, and the insulating adhesive paper 6 fixes the extension portion 31. After the insulating tape 6 is fixed to the extension portion 31 on the side wall of the winding structure, the problem of exposed battery core caused by the separation of the isolation film 3 can be avoided. The insulating effect of the insulating layer formed by the isolation film 3 is reinforced. In addition, the insulating tape 6 itself also has insulating properties, which can provide an extra layer of insulating layer for the battery core to improve the insulating performance of the battery core. The insulating tape 6 may be fixed only at the end of the extension portion 31, or it may be arranged at least one circle around the side wall to surround the isolation film 3.

In one embodiment of the present invention, a battery cell of an energy storage device is provided, which includes a positive electrode sheet 1, a negative electrode sheet 2 and two separators 3, and one of the positive electrode sheet 1 and the negative electrode sheet 2 is located in two Between the separators 3, the other is located outside one of the separators 3. The positive electrode sheet 1, the negative electrode sheet 2 and the two separator films 3 form a spiral winding structure, and the winding structure A through hole 5 is formed in the middle of the structure.

In this embodiment, as shown in FIG. 2 and FIG. 3, the positive electrode sheet 1, the negative electrode sheet 2 and the separator 3 are wound to form a spiral winding structure. A through hole 5 is formed at the position where the winding needle 4 is located. During the process of arranging the battery core into the shell of the energy storage device, the electrical connection portion provided on the battery core is welded through the through hole 5, and there is no need to set an excessively long electrical connection portion, which avoids the electrical connection portion in the energy storage device There is a problem that bending affects the structural strength of the electrical connection part. In addition, it is not necessary to install the electric core in the housing after welding the electrical connection part, which simplifies the steps of assembling the energy storage device.

The above embodiment focuses on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the conciseness of the text, it will not be omitted here. Go into details.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims

A method for preparing a battery cell of an energy storage device, which is characterized in that:

Clamp either the positive electrode sheet or the negative electrode sheet between the two separators;

Disposing the other of the positive electrode sheet and the negative electrode sheet on the outside of one of the isolation membranes;

Start winding from the same end of the positive electrode sheet, the negative electrode sheet and the two separators, and wind them on the winding needle to form a spiral winding structure;

At least one of the isolation membranes has an extension part protruding from the end of the positive electrode sheet and the end of the negative electrode sheet, and the extension part is fixed on the side wall of the winding structure;

The winding needle is drawn away from the winding structure to form a through hole in the middle of the winding structure.
The preparation method according to claim 1, wherein along the axial direction of the winding structure, the size of the negative electrode sheet is greater than the size of the positive electrode sheet by at least 0.1 mm.
The preparation method according to claim 1 or 2, characterized in that, along the axial direction of the winding structure, the sizes of the two separators are both larger than the size of the negative electrode sheet by at least 0.5 mm.
The preparation method according to any one of claims 1 to 3, wherein, along the axial direction of the winding structure, the part of the separator that is larger than the size of the negative electrode sheet is wound in the winding structure. The two ends of the structure form protrusions, and the protrusions are tilted to cover the positive electrode sheet and the negative electrode sheet at both ends.
The preparation method according to any one of claims 1 to 4, wherein along the circumferential direction of the winding structure, the size of the negative electrode sheet is greater than the size of the positive electrode sheet by at least 3 mm.
The preparation method according to any one of claims 1 to 5, wherein the aperture of the through hole is 0.5 mm-3.0 mm.
The preparation method according to any one of claims 1-6, wherein the positive electrode sheet and the negative electrode sheet are respectively provided with electrical connection parts, and one of the electrical connection parts protrudes from the coil. Around one end of the structure in the axial direction, the other electrical connection portion protrudes from the other end of the winding structure, and an insulating layer is provided between the electrical connection portion and the corresponding end portion.
The preparation method according to any one of claims 1-7, wherein after the winding needle is drawn out, a cylindrical core is arranged in the through hole, and the cylindrical core has an inner hole .
The preparation method according to any one of claims 1-8, characterized in that, before winding the laminated structure along the winding needle, a cylindrical cylindrical core is sleeved on the winding needle.
The preparation method according to any one of claims 1-9, wherein the winding needle has a cylindrical shape, an elliptical cylindrical shape, a prismatic shape, or a rectangular parallelepiped shape.
The preparation method according to any one of claims 1-10, wherein at least one of the two isolation films protrudes from the positive electrode sheet and the negative electrode sheet at the beginning of the winding structure.
A battery cell of an energy storage device, which is characterized by comprising a positive electrode sheet, a negative electrode sheet, and two separators, one of the positive electrode sheet and the negative electrode sheet is located between the two separators, and the other is located on one of the separators. Outside the separator, the positive electrode sheet, the negative electrode sheet, and the two separator films form a spiral winding structure, and a through hole is formed in the middle of the winding structure.