WO2017113099A1

WO2017113099A1 - Secondary battery and preparation method therefor

Info

Publication number: WO2017113099A1
Application number: PCT/CN2015/099443
Authority: WO
Inventors: 李伟; 於洪将
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2015-12-29
Filing date: 2015-12-29
Publication date: 2017-07-06

Abstract

Provided are a secondary battery and a preparation method therefor. The secondary battery comprises: a shell having four side walls and a bottom wall together enclosing an internal space; and a bare battery cell accommodated in the internal space of the shell, wherein at least one side wall of the four side walls of the shell recesses towards the interior of the shell so as to enable an outer surface of the side wall recessing towards the interior of the shell to be concave, and enable an inner surface to protrude towards the interior of the shell and abut against a corresponding surface of the bare battery cell, thereby clamping and fixing the bare battery cell into the shell. In a secondary battery according to the present invention, after a side wall of a shell recesses towards the interior of the shell, an inner surface of the side wall abuts against a corresponding surface of a bare battery cell, and inner surfaces of various side walls and a bottom wall together clamp the bare battery cell and fix the bare battery cell into the shell. The movement of a bare battery cell can also be avoided by clamping and fixing the bare battery cell only by means of a shell itself without adding an additional component, and a manufacturing process is simple.

Description

Secondary battery and preparation method thereof

Technical field

The present invention relates to the field of batteries, and in particular to a secondary battery and a method of fabricating the same.

Background technique

In the prior art, the bare cell is fixed by embedding a three-dimensional shape pressure-sensitive adhesive between the bare cell and the casing, the process is complicated, and the pressure-sensitive adhesive tape needs to consume a part of the electrolyte, which requires Increasing the amount of liquid injected into the battery leads to a significant increase in manufacturing costs. At the same time, the energy density of the cell is reduced due to the weight gain of the electrolyte and the weight of the pressure-sensitive adhesive tape itself.

Summary of the invention

In view of the problems in the prior art, an object of the present invention is to provide a secondary battery and a method of fabricating the same that can prevent the bare cell from being moved by the housing itself without adding additional components. And the manufacturing process is simple.

In order to achieve the above object, in a first aspect, the present invention provides a secondary battery comprising: a case having four side walls and a bottom wall which together form an internal space; and a bare cell housed in the case Inside the body's interior space. Wherein at least one of the four side walls of the housing is recessed into the housing such that the outer surface of the concave side wall of the housing is concave and the inner surface protrudes into the housing and abuts against the bare cell. Corresponding surfaces to clamp and secure the bare cell within the housing.

In order to achieve the above object, in a second aspect, the present invention provides a method of fabricating a secondary battery, comprising the steps of: accommodating a bare cell in an internal space in a housing, the internal space being four by a housing The side wall and a bottom wall are enclosed together; the top cover is disposed on the top of the casing to enclose the bare cell in the inner space of the casing; before the liquid injection hole on the top cover of the secondary battery is closed, the injection is made The liquid hole evacuates the inner space of the casing to a predetermined degree of vacuum, and the constant pressure is allowed to stand for a period of time so that the outer surface of the concave side wall of the casing is concave and the inner surface protrudes into the casing and abuts against the bare electric The corresponding surface of the core, thereby holding and securing the bare cell within the housing.

In order to achieve the above object, in a third aspect, the present invention provides a preparation method of a secondary battery The method includes the steps of: accommodating the bare cell in an inner space in the casing, the inner space being surrounded by four side walls of the casing and a bottom wall; and placing the top cover on the top of the casing to The bare cell is enclosed in the inner space of the casing; after the liquid injection hole on the top cover of the secondary battery is closed, the secondary battery is placed in the positive pressure box, and the constant pressure is allowed to stand for a period of time to make The outer surface of the recessed side wall of the housing is concave and the inner surface projects into the housing and against the corresponding surface of the bare cell, thereby clamping and securing the bare cell within the housing.

In order to achieve the above object, in a fourth aspect, the present invention provides a method of fabricating a secondary battery, comprising the steps of: accommodating a bare cell in an internal space in a housing, the internal space being four by a housing The side wall and a bottom wall are enclosed together; the top cover is disposed on the top of the casing to enclose the bare cell in the inner space of the casing; after the liquid injection hole on the top cover of the secondary battery is closed, the convex is made The pressing plate is pressed against the corresponding side wall so that the corresponding side wall of the housing is recessed to a certain extent to the housing, and then remains stationary for a period of time, thereby being concave toward the outer surface of the concave side wall of the housing. The inner surface projects into the housing and abuts against a corresponding surface of the bare cell.

The beneficial effects of the present invention are as follows:

In the secondary battery according to the present invention, after the side walls of the casing are recessed into the casing, the inner surface of the side walls abut against the corresponding surfaces of the bare cells, and the inner surfaces of the side walls are held together with the bottom wall. The core and the bare cell are fixed in the housing. This kind of no additional component is only clamped and fixed to the bare cell through the housing itself, and the movement of the bare cell can be avoided, and the manufacturing process is simple.

In the method of producing a secondary battery according to the present invention, the internal space of the casing is evacuated by a liquid injection hole and a constant gas pressure is formed. During the vacuuming process, the air pressure outside the casing is greater than the air pressure inside the casing, and the corresponding side wall is convex in the casing under the action of the external air pressure to prepare the secondary battery according to the first aspect of the invention, The force on the side walls is uniform, so that the concave surface of the side walls is smoother and more uniform.

In the method for producing a secondary battery according to the present invention, the secondary battery is placed in a positive pressure tank, and the air pressure in the positive pressure tank is greater than the internal pressure of the casing of the secondary battery, under the action of the air pressure in the positive pressure tank The respective side walls are convex toward the inside of the casing to prepare the secondary battery of the first aspect of the invention, and since the force of the air pressure on the side wall is uniform, the concave surface of the side wall is more smooth and uniform.

DRAWINGS

Figure 1 is a plan view of a secondary battery according to the present invention;

Figure 2 is a front elevational view of a secondary battery in accordance with the present invention;

Figure 3 is a cross-sectional view taken along line A-A of Figure 1;

Figure 4 is a cross-sectional view taken along line B-B of Figure 1;

Figure 5 is a cross-sectional view taken along line C-C of Figure 2;

6 to 8 are process flow diagrams of an embodiment of a method of manufacturing a secondary battery according to the present invention.

Among them, the reference numerals are as follows:

1 housing S internal space

11 side wall 2 bare cell

111 outer surface 21 ear

112 inner surface 3 top cover

113 edge part 31 injection hole

114 concave C concavity value

P concave apex B plate

12 bottom wall W width

detailed description

The secondary battery of the present invention and a method of producing the same will be described in detail below with reference to the accompanying drawings.

First, a secondary battery according to the first aspect of the invention will be described.

1 to 5, a secondary battery according to the present invention includes: a casing 1 having four side walls 11 and a bottom wall 12 which together form an internal space S; and a bare cell 2 housed in the casing 1 The interior space S is inside. Wherein at least one of the four side walls 11 of the housing 1 is recessed toward the housing 1 such that the outer surface 111 of the recessed side wall 11 of the housing 1 is concave and the inner surface 112 is facing the housing. 1 protrudes and abuts against the corresponding surface of the bare cell 2, thereby holding and fixing the bare cell in the casing 1.

In the secondary battery according to the present invention, after the side wall 11 of the casing 1 is recessed toward the casing 1, the inner surface 112 of the side wall 11 abuts against the corresponding surface of the bare cell 2, and the inner surface 112 of each side wall 11 The bare cell is held together with the bottom wall 12, and the bare cell is fixed in the casing 1. This additional component is not clamped and fixed only by the housing 1 itself, and the movement of the bare cell can be avoided, and the manufacturing process is simple.

In an embodiment, referring to Figures 1, 2 and 5, the inwardly concave side wall 11 of the housing 1 has: The edge portion 113 is disposed around the outer surface 113 of the side wall 11; and the concave portion 114 is surrounded by the edge portion 113 from the periphery.

In an embodiment, referring to Fig. 5, the edge portion 113 is a shape having a constant width.

In an embodiment, the width W of the edge portion is 5 mm. In an embodiment, referring to FIGS. 1 through 5, the concave apex P of the side wall 11 recessed toward the housing 1 is located at the center of the recess 114 of the side wall 11. It is added here that the concave apex P is located at the center of the concave portion 114 of the side wall 11 is the most desirable concave effect of the present invention, but it is not limited to this, because the position of the concave apex P necessarily has a certain position based on the manufacturing process. change. It is additionally mentioned here that, for the convenience of the measurement, the corresponding concave side walls 11 are measured from the outside of the housing 1 to indirectly reflect the corresponding recess of the internal space S.

In an embodiment, referring to FIG. 5, the vertical distance from the concave apex P to the edge of the plane formed by the concave portion 114 and the edge portion 113 is a concavity value C, and the concavity value C may be 0.1 mm to 2 mm, which is preferred in the present invention. The range of the concavity value C is of course not limited to this, and the range of the concavity value C can be appropriately changed.

In an embodiment, referring to FIGS. 1 to 5, at least two of the four side walls 11 of the housing 1 are recessed toward the housing 1.

In an embodiment, the difference in the concavity values C of any two concave side walls 11 of the housing 1 may be less than 0.5 mm.

In an embodiment, the side wall 11 of the housing 1 may have a thickness of 0.05 mm to 3 mm.

In an embodiment, the bare cell 2 can be a wound cell, a laminated cell, or a wound plus laminated cell.

In an embodiment, two of the four opposite side walls 11 of the housing 1 are recessed toward the bare cell 2 such that the two sidewalls 11 are from the bare cell 2 The side abuts, clamps and fixes the bare cell 2 in the housing 1.

In an embodiment, two of the four side walls 11 of the housing 1 are oppositely recessed toward the bare cell 2 such that the two side walls 11 are from the bare cell 2 The side abuts, clamps and fixes the bare cell 2 in the housing 1.

In an embodiment, referring to FIG. 3, the bare cell 2 has a tab 21 . Referring to FIGS. 2 to 4, the secondary battery further includes a top cover 3 disposed at the top of the housing 1 to enclose the bare cell 2 in the internal space S of the housing 1 and with the bare cell 2 The tabs 21 are electrically connected.

In an embodiment, the housing 1 can be a hard shell. Further, the hard case may be a pure metal case or an alloy case. Further, the pure metal casing may be an aluminum casing or a steel casing.

In an embodiment, the housing 1 can be a single layer housing or a multilayer composite housing. When the housing 1 is a multilayer composite housing, at least one of the layers may be a pure metal or alloy.

In the secondary battery according to the present invention, in one embodiment, the coordinate data of each point on the outer surface 112 of the concave side wall 11 of the housing 1 is scanned by the flat measuring instrument, and the side wall is automatically removed. The data point of the edge portion 113 of 11 (the plane measuring instrument is set according to the width of the edge portion 113), and then the obtained data is fitted to a curved surface to obtain the height difference between the highest point and the lowest point of the curved surface, that is, the side wall 11 The concavity value and verify that the concavity value is within the range allowed by the qualified battery. The plane measuring instrument can use the core flatness tester of Zhengye Technology ASIDA-PM1000 model.

Next, a method of preparing a secondary battery according to a second aspect of the present invention will be described.

The method for producing a secondary battery according to the present invention is for use in the preparation of the secondary battery of the first aspect of the invention, comprising the steps of: accommodating the bare cell 2 in the internal space S in the casing 1, the internal space S The four side walls 11 of the casing 1 and the bottom wall 12 are enclosed together; the top cover 3 is placed on the top of the casing 1 to enclose the bare cell 2 in the internal space S of the casing 1; Before the liquid injection hole 31 on the top cover 3 of the battery is closed, the internal space S of the casing 1 is evacuated to a predetermined degree of vacuum through the liquid injection hole 31, and the constant pressure is allowed to stand for a certain period of time so as to be concave toward the casing 1. The outer surface 111 of the side wall 11 is concave and the inner surface 112 projects into the housing 1 and abuts against the corresponding surface of the bare cell 2, thereby clamping and fixing the bare cell 2 within the housing 1.

In the method of producing a secondary battery according to the present invention, the internal space S of the casing 1 is evacuated by the liquid injection hole 31 and a constant gas pressure is formed. During the vacuuming process, the external air pressure of the casing 1 is greater than the internal air pressure of the casing 1, and the corresponding side wall 11 is convex toward the casing 1 under the action of the external air pressure to prepare the secondary battery according to the first aspect of the invention. However, since the force of the air pressure on the side wall 11 is uniform, the concave surface of the side wall 11 is smoother and more uniform.

According to the method for producing a secondary battery of the present invention, in one embodiment, the prescribed degree of vacuum may be -100 kPa to -10 kPa, but not limited thereto, and may be appropriately adjusted as needed.

According to the method for producing a secondary battery of the present invention, in one embodiment, the time for standing at a constant pressure is 5 to 60 s, but not limited to this, the time for standing at a constant pressure can be appropriately lengthened or shortened depending on the specific case.

According to the method of manufacturing a secondary battery of the present invention, in an embodiment, when the corresponding side wall 11 of the housing 1 is recessed into the housing 1, the top cover 3 and the bottom wall 12 of the housing 1 and other side walls 11 is externally restricted without concave deformation. During the preparation of the secondary battery, when a part of the side wall 11 of the casing 1 is recessed into the casing 1, a flat jig can be used to abut against other side walls 11 and bottom which do not need to be recessed. The wall 12 and the top cover 3 are provided to limit deformation of the side wall 11, the bottom wall 12 and the top cover 3 which do not require recesses.

Next, a method of preparing a secondary battery according to a third aspect of the present invention will be described.

The method for producing a secondary battery according to the present invention is for use in the preparation of the secondary battery of the first aspect of the invention, comprising the steps of: accommodating the bare cell 2 in the internal space S in the casing 1, the internal space S The four side walls 11 of the casing 1 and the bottom wall 12 are enclosed together; the top cover 3 is placed on the top of the casing 1 to enclose the bare cell 2 in the internal space S of the casing 1; After the liquid injection hole 31 on the top cover 3 of the battery is closed, the secondary battery is placed in the positive pressure tank, and the constant pressure is allowed to stand for a period of time so that the outer surface 111 of the side wall 11 recessed toward the casing 1 is made. The inner surface 112 projects into the housing 1 and abuts against the corresponding surface of the bare cell 2, thereby clamping and fixing the bare cell 2 within the housing 1.

In the method for producing a secondary battery according to the present invention, the secondary battery is placed in a positive pressure tank, the air pressure in the positive pressure tank is greater than the internal pressure of the casing 1 of the secondary battery, and the air pressure in the positive pressure tank The lower corresponding side wall 11 is convex toward the casing 1 to prepare the secondary battery according to the first aspect of the present invention, and since the force of the air pressure on the side wall 11 is uniform, the concave surface of the side wall 11 is smoother. Evenly.

According to the method of producing a secondary battery of the present invention, in an embodiment, the relative pressure in the positive pressure tank may be 0.1 MPa to 0.3 MPa, but not limited thereto, and may be appropriately adjusted as needed.

According to the method for preparing a secondary battery of the present invention, in one embodiment, the constant voltage of the secondary battery is allowed to stand for 1 minute to 120 minutes, but not limited to this, the time for standing at a constant pressure may be appropriately determined according to specific conditions. Extend or shorten.

According to the method of manufacturing a secondary battery of the present invention, in an embodiment, when the corresponding side wall 11 of the housing 1 is recessed into the housing 1, the top cover 3 and the bottom wall 12 of the housing 1 and other side walls 11 is externally restricted without concave deformation. During the preparation of the secondary battery, when a part of the side wall 11 of the casing 1 is recessed into the casing 1, a flat jig can be used to abut against the other side walls 11, the bottom wall 12 and the top cover 3 which do not need to be recessed. In order to limit the deformation of the side wall 11, the bottom wall 12, and the top cover 3 that do not need to be recessed.

Finally, a method of producing a secondary battery according to a fourth aspect of the present invention will be described.

Referring to FIGS. 6 to 8, a method of manufacturing a secondary battery according to the present invention is for producing the secondary battery according to the first aspect of the present invention, comprising the steps of: accommodating the bare cell 2 in an internal space S in the casing 1. The inner space S is surrounded by the four side walls 11 of the casing 1 and one bottom wall 12; the top cover 3 is placed on the top of the casing 1 to enclose the bare cell 2 inside the casing 1. Space S; After the liquid injection hole 31 on the top cover 3 of the secondary battery is closed, the convex pressure plate B is pressed toward the corresponding side wall 11 so that the corresponding side wall 11 of the housing 1 is recessed toward the housing 1 to a certain extent. The extent is then left to rest for a period of time such that the outer surface 111 of the recessed side wall 11 of the housing 1 is concave and the inner surface 112 projects into the housing 1 and against the corresponding surface of the bare cell 2.

According to the method for producing a secondary battery of the present invention, in one embodiment, the standing time is from 0.5 min to 10 min, but not limited thereto, the time of standing at a constant pressure may be appropriately lengthened or shortened depending on the specific case.

Claims

A secondary battery comprising:

a housing (1) having four side walls (11) and a bottom wall (12) enclosed together as an internal space (S);

The bare cell (2) is housed in the inner space (S) of the casing (1);

It is characterized in that

At least one of the four side walls (11) of the casing (1) is recessed toward the casing (1) so as to be directed to the outer surface of the concave side wall (11) of the casing (1) ( 111) concave and the inner surface (112) protrudes into the housing (1) and abuts against a corresponding surface of the bare cell (2), thereby clamping and fixing the bare cell (2) to the housing (1) )Inside.
The secondary battery according to claim 1, wherein the inwardly concave side wall (11) of the casing (1) has:

An edge portion (113) located around the outer surface (113) of the side wall (11);

The recess (114) is surrounded by the edge portion (113) from the periphery.
The secondary battery according to claim 2, wherein the edge portion (113) is a shape having a constant width (W).
The secondary battery according to claim 3, wherein the width (W) of the edge portion is 5 mm.
The secondary battery according to claim 1, characterized in that the concave apex (P) of the side wall (11) recessed toward the casing (1) is located at the center of the concave portion (114) of the side wall (11).
The secondary battery according to claim 5, wherein a vertical distance from a concave apex (P) to a plane formed by an edge of the concave portion (114) and the edge portion (113) is a concave value (C), a concavity The value (C) is 0.1 mm to 2 mm.
A secondary battery according to claim 6, characterized in that at least two of the four side walls (11) of the casing (1) are recessed toward the casing (1).
The secondary battery according to claim 7, wherein the difference in the concavity value (C) of any two concave side walls (11) of the casing (1) is less than 0.5 mm.
The secondary battery according to claim 1, wherein the side wall (11) of the casing (1) has a thickness of 0.05 mm to 3 mm.
The secondary battery according to claim 1, wherein the bare cell (2) is a wound cell, a laminated cell or a wound plus laminated cell.
A secondary battery according to claim 1, wherein two of the four side walls (11) of the casing (1) are opposed to each other in the bare cell (2) The recesses are such that the two side walls (11) abut against, hold from, and secure the bare cells (2) in the housing (1) from both sides of the bare cell (2).
The secondary battery according to claim 1, wherein

The bare cell (2) has a tab (21);

The secondary battery further includes a top cover (3) disposed at the top of the casing (1) to enclose the bare cell (2) in the internal space (S) of the casing (1) and to be bare The tabs (21) of the core (2) are electrically connected.
The secondary battery according to claim 1, wherein the casing (1) is a hard shell.
The secondary battery according to claim 13, wherein the hard case is a pure metal case or an alloy case.
The secondary battery according to claim 14, wherein the pure metal casing is an aluminum casing or a steel casing.
The secondary battery according to claim 13, wherein the casing (1) is a single-layered casing or a multi-layered composite casing.
The secondary battery according to claim 13, wherein when the casing (1) is a multilayer composite casing, at least one of the plurality of layers is a pure metal or an alloy.
A method of producing a secondary battery for preparing the secondary battery according to any one of claims 1 to 17, comprising the steps of:

The bare cell (2) is housed in an inner space (S) in the casing (1), the inner space (S) being composed of four side walls (11) of the casing (1) and a bottom wall (12) ) together;

Providing a top cover (3) on the top of the casing (1) to enclose the bare cell (2) in the inner space (S) of the casing (1);

Before the liquid injection hole (31) on the top cover (3) of the secondary battery is closed, the internal space (S) of the casing (1) is evacuated to a prescribed vacuum degree through the liquid injection hole (31), and the constant pressure is static. The period of time is such that the outer surface (111) of the concave side wall (11) of the casing (1) is concave and the inner surface (112) protrudes into the casing (1) and abuts against the bare cell The corresponding surface of (2), thereby holding and fixing the bare cell (2) in the casing (1).
The method of producing a secondary battery according to claim 18, wherein the predetermined degree of vacuum is -100 kPa to -10 kPa.
The method of producing a secondary battery according to claim 18, wherein the time during which the constant pressure is allowed to stand is 5 to 60 s.
The method of manufacturing a secondary battery according to claim 18, wherein the top cover (3) and the bottom of the casing (1) are recessed when the respective side walls (11) of the casing (1) are recessed toward the casing (1) Both the wall (12) and the other side walls (11) are externally constrained without concave deformation.
A method of producing a secondary battery for preparing the secondary battery according to any one of claims 1 to 17, comprising the steps of:

The bare cell (2) is housed in an inner space (S) in the casing (1), the inner space (S) being composed of four side walls (11) of the casing (1) and a bottom wall (12) ) together;

Providing a top cover (3) on the top of the casing (1) to enclose the bare cell (2) in the inner space (S) of the casing (1);

After the liquid injection hole (31) on the top cover (3) of the secondary battery is closed, the secondary battery is placed in the positive pressure tank, and the constant pressure is allowed to stand for a period of time so as to be in the casing (1). The outer surface (111) of the concave sidewall (11) is concave and the inner surface (112) projects into the housing (1) and abuts against the corresponding surface of the bare cell (2), thereby burying the bare cell ( 2) Clamped and fixed in the housing (1).
The method of producing a secondary battery according to claim 22, wherein the relative pressure in the positive pressure tank is 0.1 MPa to 0.3 MPa.
The method of producing a secondary battery according to claim 22, wherein the secondary battery is allowed to stand at a constant pressure for 1 minute to 120 minutes.
The method of manufacturing a secondary battery according to claim 22, wherein when the corresponding side wall (11) of the casing (1) is recessed toward the casing (1), the top cover (3) and the casing ( The bottom wall (12) and the other side walls (11) of 1) are both externally constrained without concave deformation.
A method of producing a secondary battery for preparing the secondary battery according to any one of claims 1 to 17, comprising the steps of:

The bare cell (2) is housed in an inner space (S) in the casing (1), the inner space (S) being composed of four side walls (11) of the casing (1) and a bottom wall (12) ) together;

Providing a top cover (3) on the top of the casing (1) to enclose the bare cell (2) in the inner space (S) of the casing (1);

After the liquid injection hole (31) on the top cover (3) of the secondary battery is closed, the convex pressure plate (B) is pressed toward the corresponding side wall (11) to make the corresponding one of the housing (1) The side wall (11) is recessed to a certain extent to the casing (1) and then left to rest for a period of time so as to be concave toward the outer surface (111) of the concave side wall (11) of the casing (1). The surface (112) projects into the housing (1) and abuts against the corresponding surface of the bare cell (2).
The method of producing a secondary battery according to claim 26, wherein the standing time is from 0.5 min to 10 min.
The method of manufacturing a secondary battery according to claim 26, wherein when the corresponding side wall (11) of the casing (1) is recessed toward the casing (1), the top cover (3) and the casing ( The bottom wall (12) and the other side walls (11) of 1) are both externally constrained without concave deformation.