WO2024022130A1

WO2024022130A1 - Jelly roll, prismatic battery, and energy storage device

Info

Publication number: WO2024022130A1
Application number: PCT/CN2023/107400
Authority: WO
Inventors: 黄汉川
Original assignee: 厦门海辰储能科技股份有限公司
Priority date: 2022-07-29
Filing date: 2023-07-14
Publication date: 2024-02-01
Also published as: CN217768481U

Abstract

A jelly roll (100), a prismatic battery, and an energy storage device. The jelly roll (100) comprises winding portions (10), wherein n winding portions (10) are provided, n is greater than or equal to 2, and n is a positive integer; each winding portion (10) comprises a separator portion (11) and two electrode sheet portions (12) which are positioned on two sides of the separator portion (11) and have opposite polarities; each winding portion (10) is wound along the axis of the jelly roll (100) or the length direction of the jelly roll (100); the plurality of winding portions (10) are wound in sequence; and the lengths of the electrode sheet portions (12) of different winding portions (10) are different.

Description

Roll cores, prismatic batteries and energy storage devices

priority information

This application requests the priority and rights of the patent application with patent application number 202221996199.4, which was submitted to the State Intellectual Property Office of China on July 29, 2022, and its full text is incorporated herein by reference.

Technical field

The present application relates to the field of battery technology, and in particular to a roll core, a prismatic battery and an energy storage device.

Background technique

In the related art, lithium-ion batteries are generally prepared by lamination or winding.

However, during the battery cycle of lithium-ion batteries prepared by the winding method, the positive electrode sheet, separator and negative electrode sheet form the electrode sheet layer. The expansion stress of the electrode sheet layer is difficult to release outward and will be released into the core, causing the electrode Wrinkles at the sheet interface, and wrinkles will cause lithium deposition in the battery, reduce cycle life, and pose high safety risks. The wrinkle problem can be optimized by coating the separator, but the cost is higher. The wrinkle problem can also be optimized by using lamination processing, but the production efficiency is low. .

Contents of the invention

This application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of this application is to propose a winding core that can optimize the wrinkle problem at the pole piece interface, reduce the risk of lithium precipitation, improve cycle life, and reduce safety risks, while taking into account both cost and production efficiency.

This application further proposes a prismatic battery using the above-mentioned roll core.

This application also proposes an energy storage device using the above-mentioned square battery.

The winding core according to the first embodiment of the present application includes: a winding part, the number of the winding parts is n, n≥2, n is a positive integer, the winding part includes: a diaphragm part and a Two pole pieces with opposite polarities on both sides of the separator, the winding part is extended and wound along the axis of the winding core or the length direction of the winding core, a plurality of the winding parts are wound in sequence, and The lengths of the pole piece portions of different winding portions are different from each other.

According to the winding core according to the embodiment of the present application, by arranging multiple winding parts and winding the multiple winding parts in sequence to form the winding core, at least one layer of pole pieces can be reduced on the bending areas at both ends of the winding core. layer to optimize the group margin, improve the wrinkles at the interface of the pole pieces, reduce the risk of lithium precipitation, extend the cycle life, and reduce safety risks. There is no need to set up a coating separator, which can reduce costs, and the non-laminated solution can improve production efficiency.

According to some embodiments of the present application, the winding core is in a quadrangular shape, and the end of the winding portion where the winding starts is the head end, and the end where the winding ends is the tail end, and during the winding process from the head end to the tail end, at least One bend. Therefore, compared with the lamination method This solution can effectively improve production efficiency and achieve faster core processing.

Furthermore, the number of bends is an odd number, and the head end and the tail end of the same winding part are located at the same end of the length direction of the square battery, so as to reduce the polarity at least at one end in the length direction. The number of layers can be increased to improve the problem of pole piece wrinkles.

Furthermore, if the number of bends is an even number, the head end and the tail end of the same winding part are located at both ends of the prismatic battery in the length direction, and can be reduced at both ends of the length direction at the same time. The number of pole piece layers in the bending area improves the problem of pole piece wrinkles at both ends in the length direction.

Further, the winding part includes: a first winding part to an n-th winding part wound sequentially from inside to outside, n≥2, n is a positive integer, and the tail end of the n-1th winding part is connected to the n-th winding part. The first end of the n winding part is located at the end on the same side in the length direction of the winding core. In this way, the winding direction and direction of the winding part can be reasonably set to effectively improve the wrinkles at the electrode piece interface and reduce the probability of lithium precipitation.

Further, the tail end of the n-1th winding part and the head end of the n-th winding part are arranged away from each other in the width direction of the winding core. This application is set up in such a way that the head ends a and tail ends b of the multiple winding parts are only separated by a layer of pole sheets. The size is reasonable, and the pressure can be effectively released while taking into account the prismatic battery. energy density.

According to some embodiments of the present application, the winding core further includes: a separation membrane, which is disposed between adjacent winding parts. The separation membrane separates adjacent winding parts, which can improve The working stability and reliability of the core.

Furthermore, the plurality of winding parts are all wound in the counterclockwise direction or are all wound in the clockwise direction, which can make the polarity of the multiple winding parts the same, thereby improving the working stability and use safety of the winding core.

The prismatic battery according to the second embodiment of the present application includes: a winding core and a battery case, the winding core is arranged in the battery case, and the winding portion extends along the length direction of the battery case And the ends are bent for coiling.

According to the prismatic battery according to the embodiment of the present application, using the above-mentioned roll core, the roll core has a longer cycle life, lower safety hazards, low cost, and high production efficiency, which can improve the working stability and use safety of the prismatic battery, and make Prismatic batteries cost less.

An energy storage device according to a third embodiment of the present application includes: the prismatic battery described in the above embodiment.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

Figure 1 is a schematic diagram of a winding core according to an embodiment of the present application;

Figure 2 is a schematic diagram of the first winding part according to an embodiment of the present application;

Figure 3 is a schematic diagram of the second winding part according to an embodiment of the present application.

Reference signs:
Core 100,
The winding part 10, the first winding part 10a, the second winding part 10b, the diaphragm part 11, the first diaphragm 111, the separation diaphragm 112,
The pole piece part 12, the first positive pole piece 121, the first negative pole piece 122, the second positive pole piece 123, the second negative pole piece 124,
Separating diaphragm 20,
Head end a, tail end b, release area c.

Detailed ways

The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application and cannot be understood as limiting the present application.

The following describes the winding core 100, the prismatic battery and the energy storage device according to the embodiment of the present application with reference to FIGS. 1-3.

As shown in Figures 1, 2 and 3, the winding core 100 according to the first embodiment of the present application includes: winding parts 10. There are n number of winding parts 10, n≥, n is a positive integer, and the number of winding parts 10 is n. The part 10 includes: a diaphragm part 11 and pole piece parts 12 located on both sides of the diaphragm part 11 and having opposite polarity. Each winding part 10 is wound along the axis of the winding core 100 or the length direction of the winding core 100. The winding parts 10 are wound in sequence, and the lengths of the pole piece parts 12 of different winding parts 10 are different.

The winding part 10 includes a pole piece part 12, a diaphragm part 11 and another pole piece part 12 that are stacked in sequence. The two pole piece parts 12 and the diaphragm part 11 of the same winding part 10 form a pole piece layer. The pole piece layer After laying it along the length direction of the winding core 100 and bending it at the end, lay it again along the length direction of the square battery and repeat it several times to complete the winding setting of a single winding part 10, or wind it along the axis of the winding core 100. .

In order to facilitate those skilled in the art to understand the technical solution of the present application, the winding part 10 can be defined according to the internal and external settings after winding, including: the first winding part 10a to the nth winding part, n≥2, n is a positive integer, where , the lengths of the pole piece layers of the multiple winding parts 10 are different from the outside to the inside, that is, the length of the pole piece 12 of the first winding part 10a is the shortest, and the length of the pole piece 12 of the nth winding part is the longest, and based on The pole piece layers are laid along the length direction, and are bent in the width direction to be rolled. After the adjacent winding portion 10 is rolled, the number of pole piece layers on at least one end of the length direction can be reduced by one layer. Formed as a release area c; or the axis of the winding core 100 is rolled and laid, and adjacent winding parts 10 are at least partially spaced to form a release area, which can optimize the group margin (referring to the actual internal cross-sectional area of the cylindrical battery and the maximum The ratio of the internal cross-sectional area; or the ratio of the size of the core 100 of the square battery to the size of the internal space of the battery case), so that the expansion stress of the pole piece layer can be released into the release area c, avoiding direct or reduced release into the inside of the core 100 pressure to alleviate or improve the wrinkles at the pole piece interface to improve the wrinkle problem at the pole piece interface, increase cycle life, and effectively reduce safety hazards.

Illustratively, as shown in Figure 1, the winding part 10 includes: a first winding part 10a and a second winding part 10b. After the winding part 10a is completed, the second winding part 10b is wound on the outside thereof, and the inner pole sheet layer and the outer pole sheet layer are spaced apart on the left end, so that the poles on the bent edge area of the left end of the winding core 100 are The number of layers can be reduced by one layer (i.e., the area where the inner electrode layer and the outer electrode layer are disconnected), effectively reducing the number of electrode layers on at least one end of the bent edge area to optimize the group margin and improve the electrode layer Wrinkle problem.

Of course, if the winding part 10 includes the first winding part 10a, the second winding part 10b and the third winding part, then one layer can be reduced on the two bending edge areas at the left and right ends shown in Figure 1 The number of pole piece layers, if the winding part 10 includes an inner winding part (first winding part 10a), an outer winding part (nth winding part) and a plurality of intermediate winding parts (second winding part 10b to the n-1th winding part), you can reduce the number of pole pieces by at least one layer on each of the left and right bending edge areas shown in Figure 1 to optimize the group margin and improve the pole pieces. folds.

It should be pointed out that the winding core 100 of the present application includes a plurality of winding parts 10 and is wound into the winding core 100 through the multiple winding parts 10. Compared with the existing technology of winding one pole sheet layer into the winding core 100 This solution can effectively optimize the group margin and improve the wrinkles of the pole sheets. It does not require the installation of coating separators, which can reduce costs. Compared with the lamination technology solution, the production efficiency is higher.

According to the winding core 100 of the embodiment of the present application, by providing multiple winding parts 10 and winding the multiple winding parts 10 in sequence to form the winding core 100, the bending areas at both ends of the winding core 100 can be reduced. At least one electrode layer is used to optimize group margin, improve electrode interface wrinkles, reduce the risk of lithium precipitation, extend cycle life, and reduce safety risks. There is no need to set up a coating separator, which can reduce costs. The non-laminated solution can improve Productivity.

It should be noted that if the number of winding parts 10 is n (n≥2), the number of pole piece layers reduced in the bending area is n-1, or n-1 gaps are formed for stress relief, and each The two pole piece portions 12 of each winding portion are configured as positive pole pieces and negative pole pieces respectively. The lengths of the two pole piece portions 12 of the same winding portion can be the same or different. In order to facilitate those skilled in the art to identify the present application In the structure of the winding core 100, the outer winding part in the drawings of this application is defined as the second winding part 10b, the inner winding part is defined as the first winding part 10a, and the diaphragm part 11 of the first winding part 10a is defined as the second winding part 10a. A separator 111, the pole piece part 12 includes a first positive pole piece 121 and a first negative pole piece 122, the separator part 11 of the second winding part 10b is defined as a second separator 112, the pole piece part 12 includes: a second positive pole piece 123 and the second negative electrode piece 124.

As shown in Figures 2 and 3, according to some embodiments of the present application, the winding core 100 is in a quadrangular shape, and the end of the winding portion 10 from which the winding starts is the head end a, and the end where the winding ends is the tail end b, and from the head end Make at least one bend during the winding process of a to the tail end b.

That is to say, the winding part 10 can be configured as a U-shape (one bend), an N-shape (two bends), an M-shape (three bends) or more bends, rather than a straight-shaped laminated pole piece. , compared with the lamination scheme, after the winding part 10 of the present application is bent and wound at least once, multiple winding parts 10 are wound in sequence. Compared with the lamination scheme, the production efficiency can be effectively improved and a faster winding core can be achieved 100 processing.

It can be understood that when the number of bends is an odd number, the head end a and the tail end b of the same winding part 10 are located at the same end of the square battery in the length direction (U-shaped, M-shaped); The number of times is an even number, and the same winding part 10 The head end a and the tail end b are located at both ends of the rectangular battery in the length direction (N shape).

Furthermore, the plurality of winding parts 10 can be bent an odd number of times, and the first ends a of two adjacent winding parts 10 are staggered in the length direction, or they can be bent an even number. In the second solution, the head ends a and the tail ends b of two adjacent winding parts 10 are arranged sequentially in the length direction, so as to simultaneously reduce the number of pole piece layers in the bending area at both ends in the length direction and improve both ends in the length direction. The end pole piece wrinkle problem.

As shown in Figure 1, the winding part 10 includes: a first winding part 10a to an n-th winding part wound sequentially from the inside to the outside, n≥2, n is a positive integer, and the tail of the n-1th winding part The end and the first end of the n-th winding part (that is, the adjacent winding core part 10 ) are located at the same end in the length direction of the winding core 100 .

For example, the inner winding part (the first winding part 10a) is laid out from right to left, and the tail end b is located at the left end, while the outer winding part (the second winding part 10b) is laid out from left to right. , and the first end a is located at the left end, so that the adjacent winding parts 10 are spaced apart on the bending area at the left end, so as to reduce a layer of pole pieces in this area. Correspondingly, the inner winding part can also be moved from right to left laying, and the outer winding part is laid from left to right, so as to reduce a layer of pole pieces on the bending area at the right end, so as to effectively improve the wrinkles of the pole piece interface through the reasonable setting of the winding direction and direction of the winding part 10 , reduce the probability of lithium precipitation.

Furthermore, the tail end a of the n-1th winding portion and the leading end b of the n-th winding portion are arranged away from each other in the width direction of the winding core 100 .

That is to say, the first end a of the n-1th winding part and the tail end b of the nth winding part are spaced apart (that is, adjacent winding parts), that is, the two are in the width direction of the winding core 100 spaced apart to make the space occupation of the release area c defined by the inner winding part and the outer winding part more reasonable. The release area c is too small to effectively release the pressure, and too large will reduce the energy density of the prismatic battery, and This application is configured in such a way that the head ends a and tail ends b of the multiple winding parts 10 are only separated by a layer of pole pieces. The size is reasonable, and the square shape can be taken into account while effectively releasing the pressure. Battery energy density.

As shown in FIG. 1 , according to some embodiments of the present application, the winding core 100 further includes: a separation membrane 20 , and the separation membrane 20 is disposed between adjacent winding parts 10 . Therefore, the adjacent winding parts 10 are separated by the separation diaphragm 20, thereby improving the working stability and reliability of the winding core 100.

Furthermore, the plurality of winding parts 10 are all wound counterclockwise or clockwise, so that the polarities of the plurality of winding parts 10 are the same, thereby improving the working stability and use safety of the winding core 100 .

The prismatic battery according to the second embodiment of the present application includes: a winding core 100 and a battery case. The winding core 100 is disposed in the battery case, and the winding portion 10 extends along the length direction of the battery case and is bent at its end. for winding.

According to the prismatic battery according to the embodiment of the present application, the above-mentioned roll core 100 is used. The roll core 100 has a longer cycle life, lower safety hazards, low cost and high production efficiency, which can improve the working stability and use safety of the prismatic battery. And make prismatic batteries cheaper.

An energy storage device according to a third embodiment of the present application includes: the prismatic battery in the above embodiment.

It should be pointed out that the energy storage device can be a battery pack, battery module, etc. composed of multiple above-mentioned prismatic batteries connected in series or parallel, or it can be a single prismatic battery. The technical effects are consistent with the above-mentioned prismatic batteries and will not be discussed here. Repeat.

In the description of this application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axis" The orientation or positional relationship indicated by "radial direction", "circumferential direction", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply the device or device referred to. Elements must have a specific orientation, be constructed and operate in a specific orientation and therefore are not to be construed as limitations on the application.

In the description of this application, "first feature" and "second feature" may include one or more of these features.

In the description of this application, "plurality" means two or more than two.

In the description of this application, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in direct contact with each other. additional characteristic contacts between.

In the description of this application, the terms "above", "above" and "above" a first feature on a second feature include the first feature being directly above and diagonally above the second feature, or simply mean that the first feature is horizontally higher than Second characteristic.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" or the like is intended to be incorporated into the description of the implementation. An example or example describes a specific feature, structure, material, or characteristic that is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present application have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principles and purposes of the present application. The scope of the application is defined by the claims and their equivalents.

Claims

A roll core, which is characterized in that it includes:

The winding part, the number of the winding parts is n, n≥2, n is a positive integer, the winding part includes: a diaphragm part and two pole piece parts located on both sides of the diaphragm part and having opposite polarity, Each of the winding parts is wound along the axis of the winding core or the length direction of the winding core, a plurality of the winding parts are wound in sequence, and the different winding parts of each other are The lengths of the pole pieces are different.
The winding core according to claim 1, characterized in that the winding core is in the shape of a quadrilateral, the end of the winding portion where the winding starts is the head end, and the end where the winding ends is the tail end, and the direction from the head end to the tail end is Make at least one bend during the winding process.
The winding core according to claim 2, characterized in that the number of bends is an odd number, and the first end and the tail end of the same winding part are located on the same side in the length direction of the winding core. One end.
The winding core according to claim 2, characterized in that the number of bends is an even number, and the first end and the tail end of the same winding part are located at both ends in the length direction of the winding core. .
The winding core according to any one of claims 2 to 4, characterized in that the winding part includes: a first winding part to an nth winding part wound sequentially from the inside to the outside, n≥2, n is a positive integer, and the tail end of the n-1th winding part and the first end of the n-th winding part are located at one end on the same side in the length direction of the winding core.
The winding core according to claim 5, wherein the tail end of the n-1th winding portion and the first end of the n-th winding portion are arranged away from each other in the width direction of the winding core.
The winding core according to any one of claims 1 to 6, further comprising: a separation diaphragm, the separation diaphragm being disposed between adjacent winding parts.
The winding core according to any one of claims 1 to 7, characterized in that the plurality of winding parts are all wound in a counterclockwise direction or are all wound in a clockwise direction.
A prismatic battery, characterized by including:

The core according to any one of claims 1-8;

An electric core case, the winding core is arranged in the electric core case, and the winding part extends along the length direction of the electric core case and the end is bent for winding.
An energy storage device, characterized by comprising: at least one prismatic battery according to claim 9.