WO2022037127A1

WO2022037127A1 - Battery case, secondary battery, and battery pack

Info

Publication number: WO2022037127A1
Application number: PCT/CN2021/091538
Authority: WO
Inventors: 王有生; 远浩; 吴清泉; 李华
Original assignee: 常州瑞德丰精密技术有限公司
Priority date: 2020-08-21
Filing date: 2021-04-30
Publication date: 2022-02-24
Also published as: CN112018277A

Abstract

The present application provides a battery case, a secondary battery, and a battery pack. The battery case comprises: a housing, the housing being U-shaped and integrally provided; and a cover plate, the cover plate being fitted to the housing, the cover plate comprising a cover plate body covering the housing and a step portion provided around the peripheral edge of the cover plate body, and the step portion comprising a first step surface abutted against an outer edge surface of the housing and a second step surface abutted against an inner surface of the housing, wherein a weld seam for welding is formed between the first step surface and the outer edge surface of the housing, an opening of the weld seam is located on one side of an outer surface of the housing, and the weld seam extends to the second step surface. The cover plate of the battery case provided in the present application is provided with the step portion, and when the weld seam formed between the top cover and the housing is sealed by welding, the thickness of the step portion formed can prevent laser from breaking through the battery housing, thereby reducing the risk of breaking through a battery cell and thus improving the product yield.

Description

A battery case, a secondary battery and a battery pack

technical field

The present application relates to the technical field of new energy batteries, in particular to a battery casing, a secondary battery and a battery pack.

Background technique

In modern society, more and more power tools and new energy vehicles drive power supply towards high capacity and high safety. Batteries are widely used in power tools and new energy vehicles due to their high capacity and other excellent characteristics. In addition to high capacity, these batteries should also have good safety in order to meet the standard of use and meet people's needs.

In general secondary batteries, in order to facilitate the assembly of the cells, the top cover and the casing are made into a "U"-shaped structure. into the casing and encapsulate the casing. When encapsulating, the top cover of the battery is covered on the casing, and then the welding seam between the top cover and the casing is sealed by welding, so as to realize the encapsulation of the battery.

technical problem

However, in the prior art, due to the large welding seam between the top cover and the casing of the battery case, and the thin casing, during laser welding, the laser is easy to break down the cell inside the casing through the welding seam. The yield rate of defective welding products will also increase.

technical solutions

The present application provides a battery case, a secondary battery and a battery pack, which aims to solve the technical problem that the top cover of the battery case and the case are welded to the battery cell in the prior art, resulting in poor welding.

In one aspect, the present application provides a battery casing, comprising:

a casing, the casing is U-shaped and integrally arranged; and a cover plate, the cover plate is matched with the casing, the cover plate comprises a cover plate body covered on the casing and a cover plate. a stepped portion extending around the cover plate body, the stepped portion comprising a first stepped surface abutting on the outer edge surface of the casing and a second stepped surface abutting on the inner surface of the casing;

Wherein, a welding seam for welding is formed between the first step surface and the outer peripheral surface of the casing, the welding seam opening is located on one side of the outer surface of the casing, and the welding seam extends to the first Two steps.

In a possible implementation manner of the present application, the first stepped surface is vertically connected to the second stepped surface.

In a possible implementation manner of the present application, the housing includes: a bottom plate and a side plate, and two sides of the bottom plate are bent to form two opposite side plates;

The cover plate further includes a top plate and an end plate, and two ends of the top plate are bent to form two opposite end plates.

In a possible implementation manner of the present application, the inner wall of the side plate and the inner wall of the bottom plate are in contact with the first stepped surface, and the end surface of the side plate and the end surface of the bottom plate are in contact with the first step surface. The two steps meet.

In a possible implementation manner of the present application, both the casing and the top cover are made of aluminum alloy.

In a possible implementation manner of the present application, the bottom plate and the side plate are connected in an arc transition, and the top plate and the end plate are connected in an arc transition.

In a possible implementation manner of the present application, poles are provided on the top plate and/or the end plate.

In a possible implementation manner of the present application, a connecting piece is connected to the pole, and the connecting piece is provided on the inner side surface of the top plate and/or the end plate.

In a possible implementation manner of the present application, the connecting piece includes a first connecting piece and a second connecting piece, the first connecting piece is welded with the pole, and an end of the first connecting piece is bent extending to form the second connecting piece.

In a possible implementation manner of the present application, the battery casing formed by the cover plate covering the casing is a rectangular casing, and the top plate is disposed along the length or width direction of the rectangular casing.

In a possible implementation manner of the present application, the casing has a length, a width and a thickness, the length is greater than the width, the width is greater than the thickness, and the length is less than 600 mm.

In a possible implementation manner of the present application, the length is greater than or equal to 500 mm and less than 600 mm.

In a possible implementation manner of the present application, the length is greater than or equal to 400 mm and less than 500 mm.

beneficial effect

A secondary battery includes a casing and a battery cell, the battery core is accommodated inside the casing, and the casing is the battery casing.

A battery pack includes a plurality of single cells connected in series and/or in parallel with each other, the single cells being the secondary battery. A cover plate of a battery case provided in the present application is provided with a step portion. Since the step portion is provided on the outer edges of the inner side walls of the top plate and the end plate, the top cover can be positioned more accurately by the step portion. The cover is attached to the case, which is easy to assemble, and when the welding seam formed on the cover plate and the case is welded and sealed, the thickness formed by the step portion can prevent the laser from penetrating the battery case, thereby reducing the risk of the battery cell being broken down. , thereby improving the yield of the product.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic structural diagram of a secondary battery provided by an embodiment of the present application;

Fig. 2 is the exploded schematic diagram of the secondary battery provided in the embodiment of the present application;

3 is a schematic structural diagram of an embodiment of the battery case provided in the embodiment of the present application;

Fig. 4 is a partial enlarged view of A in Fig. 3 in the embodiment of the present application;

5 is a schematic cross-sectional view of the battery case provided in FIG. 1 in an embodiment of the present application;

Fig. 6 is a partial enlarged view of the step portion of Fig. 5 in the embodiment of the present application;

FIG. 7 is a schematic structural diagram of an embodiment of the stepped portion provided in FIG. 5 in the embodiment of the present application;

FIG. 8 is a schematic structural diagram of yet another embodiment of the battery case provided in the embodiment of the present application.

BEST MODE FOR CARRYING OUT THE INVENTION

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " The orientation or positional relationship indicated by "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation shown in the drawings Or the positional relationship is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features delimited with "first", "second" may expressly or implicitly include one or more of said features. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is presented to enable any person skilled in the art to make and use the present invention. In the following description, details are set forth for the purpose of explanation. It will be understood that one of ordinary skill in the art will realize that the present invention may be practiced without the use of these specific details. In other instances, well-known structures and procedures have not been described in detail so as not to obscure the description of the present invention with unnecessary detail. Thus, the present invention is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Embodiments of the present application provide a battery casing, a secondary battery, and a battery pack, which will be described in detail below.

On the one hand, as shown in FIG. 1 and FIG. 2 , an embodiment of the present application provides a secondary battery, including a casing 10 and a battery cell 20 , the battery cell 20 is accommodated inside the casing 10 , the casing 10 is a battery casing, and the battery casing 10 The structure is as follows:

As shown in FIG. 3 and FIG. 4 , the battery case 10 provided by the embodiment of the present application includes: a cover plate 100 and a casing 200 .

The casing 200 is U-shaped and integrally arranged;

The cover plate 100 is matched with the casing 200 , and the cover plate 100 is covered with the casing 200 to form a battery shell. The stepped portion 130 includes a first stepped surface 131 abutting on the outer peripheral surface of the casing 200 and a second stepped surface 132 abutting on the inner surface of the casing 200 .

The welding seam 101 for welding is formed between the first stepped surface 131 and the outer surface of the casing 200 .

In the embodiment of the present application, since the stepped portion 130 is provided on the outer edges of the inner side walls of the top plate 110 and the end plate 120, the top plate 110 can be more accurately covered on the casing 200 by the positioning of the stepped portion 130, which is easy to assemble, and When the welding seam 101 is formed on the cover plate 100 and the casing 200 for welding and sealing, the thickness of the step portion 130 can prevent the laser from penetrating the battery casing, thereby reducing the risk of the battery being broken down, thereby improving the quality of the product Rate.

The stepped portion may have various forms, such as a first-step stepped portion. As shown in FIG. 5 and FIG. 6 , the stepped portion 130 is disposed on the side of the top plate 110 facing the bottom plate, and is disposed on both sides of the top plate 110. 130 includes a first stepped surface 131 and a second stepped surface 132, the first stepped surface 131 is vertically connected with the second stepped surface 132, the inner wall of the side plate 220 and the inner wall of the bottom plate 210 are in contact with the second stepped surface 132, and the side plate The end surface of 220 and the end surface of the bottom plate 210 are in contact with the first stepped surface 131, and through the arrangement of the first stepped surface 131 and the second stepped surface 132, the end surfaces of the first stepped surface 131 and the side plate 220 facing the cover plate 100 are formed. When the welding seam is welded and sealed, since the direction of the laser is parallel to the plane of the water 131 on the first step surface during welding, the thickness formed by the step can prevent the laser from penetrating the battery case, thereby reducing the breakdown of the battery cell. risk, thereby increasing the yield of the product.

As shown in FIG. 7 , the stepped portion 130 may also be a second-step stepped portion, and the stepped portion 130 includes a first stepped surface 131 and a second stepped surface 132, a third stepped surface 133 and a fourth stepped surface 134, which are connected in sequence. The stepped surface 131 is vertically connected with the second stepped surface 132 , the third stepped surface 133 and the fourth stepped surface 134 have the same structure, and the third stepped surface 133 and the first stepped surface 131 are arranged parallel to and opposite to the first stepped surface 131 . Extending in the direction of the side plate and the bottom plate corresponding to the edge of the step portion is correspondingly provided with a second-step step portion, the second-step step portion and the shell step portion can also prevent laser welding from penetrating the battery case, and through the setting of the second-step step portion When the welding seam 101 formed on the first step surface 131 and the end face of the side plate 220 facing the cover plate 100 is welded and sealed, since the laser is along the horizontal direction parallel to the first step surface 131, and the second step portion is formed The thickness is thicker than that of the first-step stepped portion, which can better prevent the laser from penetrating the battery case.

The cover plate body 11 further includes a top plate 110 and an end plate 120. The number of end plates 120 is two, including a first end 121 and a second end plate 122, wherein two ends of the top plate 110 are bent to form opposite first end plates 121 and the second end plate 122, the step portion 130 is provided on the outer edges of the top plate 110, the first end plate 121 and the second end plate 122, the top plate 110, the first end plate 121 and the second end plate 122 The U-shaped cover plate 100 is formed by processing.

The housing 200 includes: a bottom plate 210 and side plates 220, wherein the number of side plates 220 is two, including a first side plate 221 and a second side plate 222, and two sides of the bottom plate 210 are bent to form opposite first side plates 221 and the second side plate 222, a accommodating cavity 230 is formed between the bottom plate 210, the first side plate 221 and the second side plate 222 for accommodating the battery cell 20, and the casing 200 can be formed by integral molding U-shaped shell. In the assembling process of the single battery, the arrangement of the U-shaped cover plate 100 and the U-shaped casing makes it easy to install the battery cell 20 into the casing, and the assembly process is simpler. The U-shaped cover plate is closed on the U-shaped casing 200 to form a rectangular battery casing.

The casing 200 and the cover plate 100 are both made of aluminum alloy. Since aluminum alloy has the characteristics of high strength and low density, the battery casing made of aluminum alloy also has the characteristics of high strength and light weight, and is easier to weld. forming.

In some embodiments, the casing has a length, a width and a thickness, the length is greater than the width, and the width is greater than the thickness, and the length of the casing 200 is less than 600 mm, which not only ensures that the assembled single battery has a certain heat dissipation area, but also ensures that The strength of the single cell itself.

Further, the length of the casing 200 is greater than or equal to 500mm and less than 600mm, or the length of the casing is greater than or equal to 400mm and less than 500mm, which is the preferred length data obtained by experience in the actual production of the present application. The casing makes it easier for the single cells to be arranged in multiple rows when assembled in the battery pack.

It should be noted that, since the battery casing is formed by covering the matched casing and the cover plate, the battery casing of this embodiment has the same beneficial effects as the length of the casing, which will not be repeated here.

Due to the relatively conventional processing methods currently used, in order to improve the energy density of the secondary battery and reduce the processing difficulty and cost, the casing is generally made of profiles with relatively small thickness, and the top cover is provided with poles, Pole holes and other structures have relatively large thickness and structural strength, and it is relatively difficult to form explosion-proof holes on a shell with a relatively small thickness, and the installation process of explosion-proof valves is also difficult to connect. Therefore, , in the embodiment of the present application, both the cover plate 100 and the casing 200 may be formed of metal materials, such as metal aluminum or aluminum alloy, and both are processed into a U-shaped structure, which is conducive to reducing the processing difficulty, and has a lightweight structure and is easy to weld. Features.

In some embodiments, the top plate 110 and the two end plates 120 are respectively connected by arc transition, and the cover plate 100 can be formed by a bending process or a stamping process. The arc transition makes the cover plate 100 easy to process.

In some embodiments, the cover plate is further provided with a pole 140, the pole 100 and 140 are arranged on the top plate and/or the end plate, and the pole 140 includes two poles, a positive pole 141 and a negative pole 142, for example, it can be a positive pole The pole 141 and the negative pole 142 are simultaneously arranged on the top plate 110, and the positive pole 141 and the negative pole 142 can also be arranged on the first end plate 111 or the second end plate 112 at the same time, or the positive pole 141 and The negative poles 142 are respectively disposed on the first end plate 111 and the second end plate 112 . The arrangement of different poles can satisfy different connection methods between the single cells in the battery pack, such as series or parallel, and is also easy to cooperate with the battery pack structures of different structures, making the assembly method of the single cells in the battery pack more flexible.

As shown in FIG. 3 , the pole 140 is provided with a connecting piece 150 . Since the connecting piece 150 is connected to the pole 141 , the connecting piece 150 will also be installed with the different positions of the pole 140 on the cover body 11 . In different positions, the connecting piece 150 can be disposed on the side of the top plate 110 facing the bottom plate, and can be disposed on the inner side surfaces of the two end plates 120 . The connecting piece 150 facilitates the connection between the positive pole 141 and the negative pole 142 and the tab of the battery cell, and can also play a role of fastening connection to ensure the connection strength between the tab and the pole 140 .

In some embodiments, the connecting piece 150 includes a first connecting piece 151 and a second connecting piece 152 , the first connecting piece 151 is welded to the pole, and the end of the first connecting piece 151 is bent and extended to form the second connecting piece 152 , During welding, place the tab 11 of the cell on the first connecting piece 151, and then bend the second connecting piece 152 to the first connecting piece 151, so that the second connecting piece 152 presses the tab 11 tightly. On the first connecting piece 151 , the first connecting piece 151 can not only prevent the positive pole 141 or the negative pole 142 from falling off the cover plate 100 , but also play a role of fastening connection, ensuring the connection between the pole 140 and the tab 11 of the battery cell. The connection strength between the positive poles 141 or the negative poles 142 is also convenient to connect with the tabs 11 .

In some embodiments, as shown in FIG. 1 and FIG. 3 , the cover body 11 is further provided with an explosion-proof valve 160, and the explosion-proof valve 160 may be disposed on at least one end plate 120. For example, the number of explosion-proof valves is one, It is arranged on the first end plate 121 or the second end plate 122 . When the poles 140 are all disposed on the top plate 110 , the explosion-proof valve 160 can be disposed on the end plate 120 to avoid too many structures on the top plate, which is beneficial to increase the strength of the top plate 110 .

Of course, the number of explosion-proof valves 160 can be set in multiples. For example, the number of explosion-proof valves 160 is 2, which are respectively disposed on the first end plate 121 and the second end plate 122 to prevent the failure of a single explosion-proof valve 160. When the secondary battery is thermally out of control, the gas cannot be pushed up and discharged from the explosion-proof valve 160 in time, causing the secondary battery to explode. It should be noted that the explosion-proof valve 160 can also achieve explosion-proof effect when the explosion-proof valve 160 is arranged on the top plate 110 . No restrictions apply.

In some embodiments, as shown in FIG. 3 and FIG. 8 , the battery casing formed by covering the cover plate 100 with the casing 200 is a rectangular casing, and the top plate 110 is disposed along the length or width direction of the rectangular casing. As shown in FIG. 3 , the top plate 110 can be arranged along the length direction of the rectangular casing. As shown in FIG. 8 , the top plate 110 can also be arranged along the width direction of the rectangular casing. The top plate 110 can be arranged along the length direction or the width direction. To achieve the same effect, it is also easy to install the battery cell 20 . The matching relationship between the cover plate 100 and the casing 200 can be referred to the previous embodiment, and details are not repeated here.

On the other hand, an embodiment of the present application further provides a battery pack, which includes a plurality of single cells connected in series and/or in parallel with each other, and the single cells are the aforementioned secondary batteries. Since the cover plate of the battery case is provided with a stepped portion, and since the stepped portion is provided on the outer edges of the inner side walls of the top plate and the end plate, the top cover can be more accurately covered on the casing by the positioning of the stepped portion, which is easy to assemble, and When welding and sealing the welding seam between the cover plate and the casing, the thickness of the step portion can prevent the laser from penetrating the battery casing, thereby reducing the risk of the battery cell being broken down, thereby improving the yield of the product. The secondary battery in this embodiment can have the same structure and achieve the same effect as the battery case of the above-mentioned embodiment, and will not be repeated in this embodiment.

A battery casing, a secondary battery and a battery pack provided by the embodiments of the present application have been described in detail above. The principles and implementations of the present invention are described with specific examples in this paper. The descriptions of the above embodiments are only used for Help to understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In conclusion, the content of this description should not be understood to limit the present invention.

Claims

A battery casing, characterized in that, comprising:

a casing, the casing is U-shaped and integrally arranged; and a cover plate, the cover plate is matched with the casing, the cover plate comprises a cover plate body covered on the casing and a cover plate. a stepped portion extending around the cover plate body, the stepped portion comprising a first stepped surface abutting on the outer edge surface of the casing and a second stepped surface abutting on the inner surface of the casing;

Wherein, a welding seam for welding is formed between the first step surface and the outer peripheral surface of the casing, the welding seam opening is located on one side of the outer surface of the casing, and the welding seam extends to the first Two steps.
The battery case according to claim 1, wherein the first stepped surface is vertically connected to the second stepped surface.
The battery casing according to claim 1, wherein the casing comprises: a bottom plate and a side plate, two sides of the bottom plate are bent to form two opposite side plates; the cover plate further comprises: A top plate and an end plate, two ends of the top plate are bent to form two opposite end plates.
The battery case according to claim 3, wherein the inner wall of the side plate and the inner wall of the bottom plate are in contact with the first stepped surface, and the end surface of the side plate and the end surface of the bottom plate are in contact with the first step surface. The second step surface is in contact with each other.
The battery casing according to claim 1, wherein the casing and the cover plate are both made of aluminum alloy.
The battery case according to claim 1, wherein the bottom plate and the side plate are connected by arc transition, and the top plate and the end plate are connected by arc transition.
The battery case according to claim 1, wherein a pole is provided on the top plate and/or the end plate.
The battery case according to claim 7, wherein a connecting piece is connected to the pole, and the connecting piece is arranged on the inner side surface of the top plate and/or the end plate.
The battery case according to claim 8, wherein the connecting piece comprises a first connecting piece and a second connecting piece, the first connecting piece is welded with the pole, and the end of the first connecting piece is welded. The part is bent and extended to form the second connecting piece.
The battery case according to any one of claims 1-9, wherein the battery case formed by the cover plate covering the casing is a rectangular case, and the top plate is along the length of the rectangular case or Width direction setting.
The battery casing of claim 10, wherein the casing has a length, a width and a thickness, the length being greater than the width, the width being greater than the thickness, and the length being less than 600 mm.
The battery case of claim 11, wherein the length is greater than or equal to 500 mm and less than 600 mm.
The battery case of claim 11, wherein the length is greater than or equal to 400 mm and less than 500 mm.
A secondary battery is characterized in that it comprises a casing and a battery cell, the battery core is accommodated inside the casing, and the casing is the battery casing according to any one of claims 1-13.
A battery pack, characterized in that it includes a plurality of single cells connected in series and/or in parallel with each other, the single cells being the secondary battery according to claim 14 .