WO2023272437A1

WO2023272437A1 - Cylindrical battery cell and battery

Info

Publication number: WO2023272437A1
Application number: PCT/CN2021/102764
Authority: WO
Inventors: Azad Darbandi; Tobias Schmieg; Qian CHENG; Chen Li
Original assignee: Hefei Gotion High-Tech Power Energy Co., Ltd.
Priority date: 2021-06-28
Filing date: 2021-06-28
Publication date: 2023-01-05
Also published as: DE212021000568U1; CN221041292U

Abstract

A cylindrical battery cell and a battery are provided. In the cylindrical cell, a cell housing is formed by a bi-metal structure, a copper layer being configured as an inside layer of the bi-metal structure and a steel layer being configured as an outside layer of the bi-metal structure. Therefore, the thickness of the cell housing can be decreased and an energy gravimetric and volumetric density of the cell can be increased.

Description

CYLINDRICAL BATTERY CELL AND BATTERY

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field of battery, and more particularly, to a cylindrical battery cell and a battery.

BACKGROUND

A battery (such as an automotive battery) in general includes a plurality of battery cell. As a kind of battery cell, a cylindrical battery cell is used recently. For example, formfactors of the cylindrical battery cell may be from 21700 (diameter is 21mm and height is 70mm) to 50120 (diameter is 50mm and height is 120mm) , and the cylindrical battery cell may at least include a cell housing and a jellyroll structure.

In general, the cylindrical battery cell needs to have a special current path within a cell design in order to ensure enough ampacity. Hence it is required a sophisticated current path design and special care of joints with enough ampacity. For example, compared to 4680 cells, large cells (e.g. 46120) have over 3 times higher energy loss in the current path through the cell housing, in case a thickness of the cell housing has not been changed.

This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

SUMMARY

However, the inventors found that in order to avoid this effect, the thickness of the cell housing has to be increased accordingly. This considerably reduces an energy gravimetric and volumetric density of the cell, that is, there are less energy and more weight per cell.

In order to solve at least part of the above problems, methods and devices are provided in the present disclosure. Features and advantages of embodiments of the present disclosure will also be understood from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the present disclosure.

In general, embodiments of the present disclosure provide a cylindrical battery cell and a battery. It is expected to decrease the thickness of the cell housing and increase an energy gravimetric and volumetric density of the cell.

In a first aspect, a cylindrical battery cell is provided. The cylindrical battery cell at least includes: a cell housing having a lateral side and a bottom side; and a jellyroll structure which is arranged inside the cell housing; wherein the cell housing is formed by a bi-metal structure, a copper layer being configured as an inside layer of the bi-metal structure and a steel layer being configured as an outside layer of the bi-metal structure.

In some embodiments, a thickness of the steel layer is from 0.2 mm to 0.25 mm and/or a thickness of the copper layer is from 0.1 mm to 0.2 mm.

In some embodiments, a ratio of a thickness of the steel layer to a thickness of the copper layer is determined by a height of the cylindrical battery cell and/or a required thermal parameter.

In some embodiments, one or more flattened tabs of the jellyroll structure are pre-welded with a copper current collector on a bottom side of the jellyroll structure, and the copper layer on the bottom side of the cell housing is welded with the copper current collector by using a laser after the jellyroll structure is inserted into the cell housing.

In some embodiments, one or more flattened tabs of the jellyroll structure are welded with the copper layer on the bottom side of the cell housing by using a laser after the jellyroll structure is inserted into the cell housing.

In some embodiments, the cylindrical battery cell further comprises: a cap component which is arranged on an upper side of the cell housing, wherein the cap component comprises an aluminum terminal and a cap plate, and the cap plate is supported by a crimped neck of the cell housing, the cap plate having a hole in which the aluminum terminal is arranged.

In some embodiments, the cap plate is welded with the copper layer at the crimped neck by using a laser to form a copper-steel joint.

In a second aspect, a battery is provided, the battery comprises a plurality of the cylindrical battery cell according to the first aspect of the embodiments.

According to various embodiments of the present disclosure, the cell housing is formed by a bi-metal structure, a copper layer being configured as an inside layer of the bi-metal structure and a steel layer being configured as an outside layer of the bi-metal structure. Therefore, the thickness of the cell housing can be decreased and an energy gravimetric and volumetric density of the cell can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and benefits of various embodiments of the disclosure will become more fully apparent, by way of example, from the following detailed description with reference to the accompanying drawings, in which like reference numerals or letters are used to designate like or equivalent elements. The drawings are illustrated for facilitating better understanding of the embodiments of the disclosure and not necessarily drawn to scale, in which:

Fig. 1 is a diagram which shows a cylindrical battery cell in accordance with an embodiment of the present disclosure;

Fig. 2 is another diagram which shows a section view of the cylindrical battery cell in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure will now be described with reference to several example embodiments. It should be understood that these embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the present disclosure, rather than suggesting any limitations on the scope of the present disclosure.

It should be understood that when an element is referred to as being “connected” or “coupled” or “contacted” to another element, it may be directly connected or coupled or contacted to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” or “directly contacted” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between” , “adjacent” versus “directly adjacent” , etc. ) .

As used herein, the terms “first” and “second” refer to different elements. The singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises, ” “comprising, ” “has, ” “having, ” “includes” and/or “including” as used herein, specify the presence of stated features, elements, and/or components and the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

The term “based on” is to be read as “based at least in part on” . The term “cover” is to be read as “at least in part cover” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

In this disclosure, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

A first aspect of embodiments

A cylindrical battery cell is provided in the embodiments.

Fig. 1 is a diagram which shows a cylindrical battery cell 100 in accordance with an embodiment of the present disclosure. Fig. 2 is another diagram which shows a section view of the cylindrical battery cell 100 in accordance with an embodiment of the present disclosure.

As shown in Fig. 1 and Fig. 2, a cylindrical battery cell 100 at least includes: a cell housing 101 and a jellyroll structure 102. The cell housing 101 has a lateral side and a bottom side. The jellyroll structure 102 is arranged inside the cell housing 101.

For example, the jellyroll structure 102 includes a rolled anode foil, a rolled cathode foil and a rolled separator between the rolled anode foil and the rolled cathode foil. As for the detail of the jellyroll structure, please refer to relevant art.

As shown in Fig. 2, the cell housing 101 is formed by a bi-metal structure; a copper layer 201 is configured as an inside layer of the bi-metal structure and a steel layer 202 is configured as an outside layer of the bi-metal structure.

It should be appreciated that some components or elements are illustrated only as examples in Fig. 1 and Fig. 2. However, it is not limited thereto, for example, connections or positions of the components or elements may be adjusted, and/or, some components or elements may be omitted. Other elements such as sealing, current collector, please refer to relevant art.

Therefore, the thickness of the cell housing can be decreased and an energy gravimetric and volumetric density of the cell can be increased. Furthermore, scalability of cell height is enabled without unproportionally loss of energy efficiency and performance. There is higher volumetric energy density in the cylindrical battery cell 100, that is, there are more energy and less weight per cell. In addition, there are enhanced cooling capability and lean module integration.

In this disclosure, a laser may be used to weld the copper layer 201 with the jellyroll structure 102 at the bottom side of the cell housing 101, and/or, weld a cap component 203 with the copper layer 201 at the upper side of the cell housing 101, but it is not limited thereto. For example, other ways such as an ultrasonic may be used in the welding process.

In some embodiments, as shown in Fig. 2, an opening may be configured on the bottom side of cell housing 101, and the copper layer 201 may be configured in the opening. Therefore, the laser may be used to weld the copper layer 201 and the jellyroll structure 102 via the opening.

In this disclosure, the copper layer 201 is configured as an inside layer of the bi-metal structure and the steel layer 202 is configured as an outside layer of the bi-metal structure. Therefore, the copper is as close as possible to a source of the heat generation (the jellyroll structure) , and it is beneficial for the thermal management.

In some embodiments, the steel layer 202 may not need to be Ni-plated since it is on the outside of the cell housing 101. Therefore, costs are reduced while risk of corrosion of cell housing is not introduced.

In some embodiments, for example, a thickness of the steel layer is from 0.2 mm to 0.25 mm, and/or, a thickness of the copper layer is from 0.1 mm to 0.2 mm (such as about 0.15 mm) . Therefore, the total thickness of the cell housing can be reduced.

In some embodiments, a ratio of a thickness of the steel layer to a thickness of the copper layer may be determined by a height of the cylindrical battery cell and/or a required thermal parameter.

For example, for a give height (such as 50 mm) and/or a required temperature (such as 20 degrees) , the ratio of the thickness of the steel layer to the thickness of the copper layer is determined according to some experimental data.

Therefore, by adjusting the thickness ratio of copper to steel, cell performance can be tailored according to specific requirements.

For example, as shown in Fig. 2, a copper current collector 204 is provided on the bottom side of the jellyroll structure 102. Furthermore, there are one or more flattened tabs in the jellyroll structure 102. The flattened tabs of the jellyroll structure 102 are pre-welded with the copper current collector 204 on the bottom of the jellyroll structure 102 (some dots in Fig. 2 are used to demonstrate laser welding footprints) .

As shown in Fig. 2, the copper layer 201 on the bottom side of the cell housing 101 is welded with the copper current collector 204 by using a laser after the jellyroll structure 102 is inserted into the cell housing 101.

Therefore, the copper current collector is pre-welded to the flattened copper tabs. The cell housing (Cu) will be laser welded to the cu current collector (Cu) afterwards, such that there is not difference in melting point when welding.

In some embodiments, one or more flattened tabs of the jellyroll structure are welded with the copper layer on the bottom side of the cell housing 101 by using a laser after the jellyroll structure is inserted into the cell housing. For example, there is not a pre-welded copper current collector.

For example, there are one or more flattened tabs in the jellyroll structure 102. The flattened tabs of the jellyroll structure 102 are welded with the copper layer 201 by using a laser after the jellyroll structure 102 is inserted into the cell housing 101.

Therefore, the copper current collector is intendedly not considered in this example. The cell housing will be directly laser welded to the flattened copper tabs of the jellyroll structure. Consequently, one manufacturing process, welding current collector (Cu) to tabs is skipped, which reduces manufacturing costs.

In some embodiments, on an upper side of the jellyroll structure, the cylindrical battery cell 100 further comprises: a cap component 203 which is arranged on an upper side of the cell housing 101. The cap component 203 may be formed by using a plastic injection mold.

As shown in Fig. 2, the cap component 203 at least includes an aluminum terminal 2031 and a cap plate 2032, and the cap plate 2032 is supported by a crimped neck 1011 of the cell housing 101, the cap plate 2032 having a hole in which the aluminum terminal 2031 is arranged. Furthermore, other elements (such as insulation element) may be used.

As shown in Fig. 2, the cap plate 2032 is arranged on the upper side of the cell housing 101, and the cap plate 2032 is supported by the crimped neck 1011 of the cell housing 101. The crimped neck 1011 may be formed by crimping/bending the cell housing 101.

In some embodiments, as shown in Fig. 2, the cap plate 2032 is welded with the copper layer 201 at the crimped neck 1011 by using a laser to form a copper-steel joint. Therefore, an electrical contact resistance of the copper-steel joint is less than a steel-steel joint, electrical conduction of cell housing can be further increased.

In this disclosure, a bi-metal (copper-steel) structure is used for the cell housing. Therefore, electrical conduction of the cell housing is increased significantly, while the total thickness of the cell housing is reduced and a volumetric filling ratio is increased. Furthermore, the technique solution of this disclosure can maximize a space usage at the bottom of the cell (higher volumetric filling ratio, higher energy content per cell, lower cost per cell mechanic) .

In addition, the technical solution enhances substantially a thermal conduction path at the cell bottom. Concurrently, high in-plane thermal conduction of jellyroll structure (in vertical axis) is achieved, this enables implementation of bottom cooling at module/pack level.

For example, implementation of bottom cooling increases volumetric filling ratio at module/pack level by minimize 5%. Implementation of bottom cooling resolves many technical challenges in integration and reduces manufacturing costs.

It is to be understood that, the above examples or embodiments are discussed for illustration, rather than limitation. Those skilled in the art would appreciate that there may be many other embodiments or examples within the scope of the present disclosure.

It can be seen from the above embodiments, the cell housing is formed by a bi-metal structure, a copper layer being configured as an inside layer of the bi-metal structure and a steel layer being configured as an outside layer of the bi-metal structure. Therefore, the thickness of the cell housing can be decreased and an energy gravimetric and volumetric density of the cell can be increased.

A second aspect of embodiments

A battery is provided in the embodiments. The corresponding devices and the method are illustrated in the first and second aspects of embodiments, and the same contents as those in the first and second aspects of embodiments are omitted.

In some embodiments, the battery includes a plurality of the cylindrical battery cell according to the first aspects of embodiments.

Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and integrated circuits (ICs) with minimal experimentation.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device.

While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous.

Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A cylindrical battery cell, at least comprising:

a cell housing having a lateral side and a bottom side; and

a jellyroll structure which is arranged inside the cell housing;

wherein the cell housing is formed by a bi-metal structure, a copper layer being configured as an inside layer of the bi-metal structure and a steel layer being configured as an outside layer of the bi-metal structure.
The cylindrical battery cell according to claim 1, wherein a thickness of the steel layer is from 0.2 mm to 0.25 mm and/or a thickness of the copper layer is from 0.1 mm to 0.2 mm.
The cylindrical battery cell according to claim 1, wherein a ratio of a thickness of the steel layer to a thickness of the copper layer is determined by a height of the cylindrical battery cell and/or a required thermal parameter.
The cylindrical battery cell according to claim 1, wherein one or more flattened tabs of the jellyroll structure are pre-welded with a copper current collector on a bottom side of the jellyroll structure, and the copper layer on the bottom side of the cell housing is welded with the copper current collector by using a laser after the jellyroll structure is inserted into the cell housing.
The cylindrical battery cell according to claim 1, wherein one or more flattened tabs of the jellyroll structure are welded with the copper layer on the bottom side of the cell housing by using a laser after the jellyroll structure is inserted into the cell housing.
The cylindrical battery cell according to claim 1, wherein the cylindrical battery cell further comprises:

a cap component which is arranged on an upper side of the cell housing, wherein the cap component comprises an aluminum terminal and a cap plate, and the cap plate is supported by a crimped neck of the cell housing, the cap plate having a hole in which the aluminum terminal is arranged.
The cylindrical battery cell according to claim 6, wherein the cap plate is welded with the copper layer at the crimped neck by using a laser to form a copper-steel joint.
A battery, comprising a plurality of cylindrical battery cells according to any one of claims 1-7.