Battery shell and battery

Abstract

The utility model discloses a battery case and battery, the battery case is used for accommodating a laminated cell, two opposite outermost layers of the laminated cell are both single-sided pole pieces, the battery case comprises a first half shell and a second half shell which are in butt joint with each other, the first half shell and the second half shell are in butt joint to form an accommodating cavity for accommodating the laminated cell, and the first half shell and the second half shell are in butt joint with each other. Each of the first half shell and the second half shell comprises a side wall opposite to the single-sided pole piece, and at least one side wall is provided with a pressing part for pressing the side edge of the single-sided pole piece. According to the battery shell disclosed by the utility model, the side edge of the single-sided pole piece is correspondingly pressed through the pressing part arranged on the side wall of the first half shell and / or the side wall of the second half shell so as to tightly bind the laminated battery cell, so that the single-sided pole piece of the laminated battery cell can be kept in a flat state, and the periphery of the single-sided pole piece is tightly attached; therefore, lithium precipitation caused by warping of the single-sided pole piece in the later cycle process is prevented, and the cycle performance of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a battery shell and a battery. Background Art

[0002] Lithium battery refers to a battery containing lithium (including metallic lithium, lithium alloys, lithium ions, and lithium polymers) in the electrochemical system and is widely used in digital products and other fields.

[0003] The mainstream types of lithium batteries on the market include wound type and stacked type. Among them, stacked type batteries can better improve battery performance compared to wound type batteries, and have advantages in energy density, safety and other aspects.

[0004] At present, in a laminated battery, the battery cell is composed of multiple stacked pole pieces, and the outermost layer is a single-sided pole piece (that is, the current collector of the pole piece is coated with an active material layer on only one side), such as a cathode single-sided pole piece or an anode single-sided pole piece. Figure 1 As shown, the single-sided electrode will warp significantly after rolling, resulting in a loose fit between the single-sided electrode and the diaphragm and other electrode sheets. The loosely fitted area is prone to lithium deposition during the later cycle process, resulting in poor battery cell cycle performance. Utility Model Content

[0005] The main purpose of the utility model is to provide a battery shell, aiming to solve the technical problem that the single-sided pole pieces in the current laminated battery core are not tightly fitted due to warping and are prone to lithium deposition.

[0006] To achieve the above-mentioned purpose, the utility model proposes a battery casing for accommodating a stacked battery cell, wherein the two opposite outermost layers of the stacked battery cell are both single-sided pole pieces, wherein the battery casing includes a first half shell and a second half shell that are butt-jointed with each other, and the first half shell and the second half shell are butt-jointed to form a accommodating cavity for accommodating the stacked battery cell, and the first half shell and the second half shell both include side walls opposite to the single-sided pole pieces, and at least one of the side walls is provided with a pressing portion for pressing the side of the single-sided pole piece.

[0007] In some embodiments, the pressing portion is formed by bending the side wall inward.

[0008] In some embodiments, the side wall is square, and the holding portions are located on two opposite sides of the side wall.

[0009] In some embodiments, the bending width of the pressing portion is 5 mm to 10 mm.

[0010] In some embodiments, the bending depth of the pressing portion is 0.1 mm to 0.5 mm.

[0011] In some embodiments, the outer surface of the side wall is a horizontal plane, and the holding portion is protruding from the inner surface of the side wall.

[0012] In some embodiments, the holding portion is fixedly connected to the inner surface of the side wall.

[0013] In some embodiments, the pressing portion includes a first pressing portion and a second pressing portion in a strip shape, and the first pressing portion and the second pressing portion press the opposite two sides of the single-sided pole piece respectively.

[0014] In some embodiments, the first half shell and the second half shell further include a peripheral wall for butting against each other, wherein the peripheral wall is disposed along an edge of the side wall and has an angle with the side wall.

[0015] The utility model also provides a battery, which includes a battery casing and a laminated battery core arranged in the battery casing, wherein two opposite side surfaces of the laminated battery core respectively have single-sided pole pieces, wherein the battery casing is the battery casing as described above.

[0016] The battery shell of the technical solution of the utility model is used to accommodate the laminated battery cell, and the two opposite outermost layers of the laminated battery cell are both single-sided pole pieces. The first half shell and the second half shell of the battery shell are butted against each other, and a receiving cavity is formed after the butt is used to accommodate the laminated battery cell. When the laminated battery cell is accommodated in the receiving cavity, the side wall of the first half shell and the side wall of the second half shell are respectively opposite to the two opposite outermost single-sided pole pieces of the laminated battery cell. At the same time, the pressing part provided on at least one side wall corresponds to the side edge of the pressing single-sided pole piece to tightly bind the laminated battery cell, so that the single-sided pole piece of the laminated battery cell can be kept flat and tightly fitted on all sides, thereby preventing the single-sided pole piece from warping and causing lithium deposition in the later cycle process, thereby improving the battery cell cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure inside a battery in the prior art;

[0018] Figure 2 This is a schematic diagram of the internal structure of a battery in one embodiment of the utility model;

[0019] Figure 3 for Figure 2 A schematic diagram of the structure of the battery exterior in the embodiment;

[0020] Figure 4 This is a schematic diagram of the internal structure of a battery in another embodiment of the utility model;

[0021] Figure 5 This is a schematic diagram of the internal structure of a battery in another embodiment of the present utility model. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the scheme in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0024] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0025] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0026] like Figure 1 As shown, in a laminated battery, a laminated battery cell 200 is accommodated by a battery housing 100, and the outermost layer of the laminated battery cell 200 is a single-sided pole piece 210, and the current collector of the single-sided pole piece 210 is coated with an active material layer on only one side. Since the single-sided pole piece 210 will be warped significantly after rolling, it will not fit tightly in the laminated battery cell 200, and the loosely fitted area is prone to lithium deposition during the later cycle process, resulting in poor battery cell cycle performance. Based on the above problems currently existing, refer to Figure 2 The embodiment of the utility model provides a battery housing 100 for accommodating a laminated battery cell 200 to prevent the single-sided electrode 210 in the laminated battery cell 200 from warping and causing lithium deposition during the later cycle process, thereby improving the cycle performance of the battery cell.

[0027] The two outermost layers of the laminated battery cell 200 are both single-sided pole pieces 210. Specifically, Figure 2As shown, the laminated battery cell 200 includes two single-sided pole pieces 210, a diaphragm 220 and a double-sided pole piece group formed by stacking double-sided pole pieces 230. The two single-sided pole pieces 210 are respectively located at the two opposite outermost layers of the laminated battery cell 200, that is, the single-sided pole piece 210 is located at the outermost layer of the double-sided pole piece group, and a diaphragm 220 is provided between the single-sided pole piece 210 and the double-sided pole piece group. Optionally, the diaphragm 220 is folded in a Z-shape, and several double-sided pole pieces 230 of the double-sided pole piece group are inserted into the diaphragm 220 and are alternately stacked with the diaphragm 220. Among them, the double-sided pole pieces 230 involved are coated with active material layers on both sides of the current collector. The two opposite outermost sides of the double-sided pole piece group are provided with single-sided pole pieces 210 stacked therewith, and a diaphragm 220 is provided between the single-sided pole piece 210 and the double-sided pole pieces 230 in the double-sided pole piece group and adjacent to and opposite to it. Among them, the single-sided pole piece 210 is usually a square sheet, such as a rectangular sheet, and its length and width are not limited here. The single-sided pole piece 210 includes a current collector and an active material layer. The active material layer is arranged on one side of the current collector. In the laminated battery cell 200, the active material layer of the single-sided pole piece 210 faces the diaphragm 220. The single-sided pole piece 210 can be a positive single-sided pole piece 210 or a negative single-sided pole piece 210, and this embodiment does not limit this. When the single-sided pole piece 210 is a positive single-sided pole piece 210, the current collector can be made of aluminum foil, and the active material layer can be made of positive active coating materials, such as lithium cobalt oxide, etc.; when the single-sided pole piece 210 is a negative single-sided pole piece 210, the current collector can be made of copper foil, and the active material layer can be made of negative active coating materials, such as graphite, etc.

[0028] Reference Figures 2 to 5 The battery housing 100 of this embodiment includes a first half shell 110 and a second half shell 120 that are butt-jointed with each other. After the first half shell 110 and the second half shell 120 are butt-jointed, a receiving cavity R for receiving the laminated battery cell 200 is formed. The first half shell 110 and the second half shell 120 both include a side wall C opposite to the single-sided pole piece 210. At least one side wall C is provided with a pressing portion Y for pressing the side edge of the single-sided pole piece 210.

[0029] Among them, the battery shell 100 can be a square shell with a flat structure as a whole. The battery shell 100 is composed of a first half shell 110 and a second half shell 120. Optionally, in addition to this name, the battery shell 100 in this embodiment can also be named by other names such as battery packaging bag and battery packaging box. The first half shell 110 can be named by other names such as bottom shell and lower shell, and the second half shell 120 can be named by other names such as upper shell and upper cover. It should be noted that the naming of the first half shell 110 and the second half shell 120 does not limit the size of the shell, and the size of the first half shell 110 and the second half shell 120 can be set according to actual conditions. After the first half shell 110 and the second half shell 120 of the battery shell 100 are docked, a receiving cavity R is formed to accommodate the laminated battery cell 200. When the laminated battery 200 is placed in the accommodating cavity R, the side wall C of the first half shell 110 and the side wall C of the second half shell 120 are respectively opposite to the two outermost single-sided pole pieces 210 of the laminated battery 200, that is, the side wall C of the first half shell 110 is opposite to the single-sided pole piece 210 of the outermost layer of the laminated battery 200, and the side wall C of the second half shell 120 is opposite to the single-sided pole piece 210 of the other outermost layer of the laminated battery 200. Optionally, both the first half shell 110 and the second half shell 120 are made of aluminum-plastic film. During assembly, the laminated battery 200 can be placed in the first half shell 110 first, and then the second half shell 120 is docked with the first half shell 110 and hot-melt packaged. The docking direction of the first half shell 110 and the second half shell 120 is based on the stacking direction or thickness direction of the laminated battery 200 as a reference direction.

[0030] Further, at least one side wall C is provided with a pressing portion Y, and the pressing portion Y is used to press the side edge of the single-sided pole piece 210. Optionally, the side wall C of the first half shell 110 is provided with a pressing portion Y, and the pressing portion Y presses the single-sided pole piece 210 opposite to the side wall C of the first half shell 110, and the side wall C of the second half shell 120 is not provided with a pressing portion Y, and is closely attached to the single-sided pole piece 210 opposite thereto. Or, as Figure 2 As shown, the side wall C of the second half shell 120 is provided with a pressing portion Y, and the pressing portion Y is pressed against the single-sided pole piece 210 opposite to the side wall C of the second half shell 120. If the side wall C of the first half shell 110 is not provided with a pressing portion, it is closely attached to the single-sided pole piece 210 opposite to it. Alternatively, as Figure 4As shown, the side wall C of the first half shell 110 and the side wall C of the second half shell 120 are both provided with a pressing portion Y, and the pressing portion Y of the side wall C of the first half shell 110 is pressed on the single-sided pole piece 210 opposite to the side wall C of the first half shell 110, and the pressing portion Y of the side wall C of the second half shell 120 is pressed on the single-sided pole piece 210 opposite to the side wall C of the second half shell 120. The pressing portion Y can be used to press part of the side edge of the single-sided pole piece 210, or it can be used to press all the side edges of the single-sided pole piece 210. Exemplarily, the single-sided pole piece 210 includes a first side edge, a second side edge, a third side edge and a fourth side edge sequentially arranged along its circumference, wherein the first side edge is opposite to the third side edge, and the second side edge is opposite to the fourth side edge. When the pressing part Y presses part of the side edges of the single-sided pole piece 210, it may press the first side edge and the third side edge of the single-sided pole piece 210, or it may press the second side edge and the fourth side edge of the single-sided pole piece 210, or it may press the first side edge, the second side edge, and the third side edge of the single-sided pole piece 210, etc., according to actual conditions. When the pressing part Y presses all the side edges of the single-sided pole piece 210, it may press the first side edge, the second side edge, the third side edge, and the fourth side edge of the single-sided pole piece 210.

[0031] In the present embodiment, the battery casing 100 uses the pressing portion Y provided on the side wall C of the first half shell 110 and / or the side wall C of the second half shell 120 to press the side edge of the single-sided pole piece 210 to tightly restrain the laminated battery cell 200, so that the single-sided pole piece 210 of the laminated battery cell 200 can be kept flat and tightly fitted on all sides, thereby preventing the single-sided pole piece 210 from warping and causing lithium deposition in the later cycle process, thereby improving the battery cell cycle performance.

[0032] In some embodiments, reference Figures 2 to 4 , the pressing portion Y is formed by bending the side wall C inward. In this embodiment, the pressing portion Y is directly formed by the side wall C structure, and the side wall C is bent inward to form the pressing portion Y. Exemplarily, each side of the side wall C is bent inward to form the pressing portion Y, and the pressing portion Y can correspond to each side edge of the single-sided pole piece 210, so that the single-sided pole piece 210 remains in a flat state, and a tight fit is achieved on all sides in the laminated battery cell 200. Among them, the first half shell 110 and the second half shell 120 are formed by stamping. Taking the first half shell 110 as an example, if the side wall C of the first half shell 110 needs to be provided with a pressing portion Y, the side wall C of the first half shell 110 can be bent inward by stamping to form the pressing portion Y; if the side wall C of the second half shell 120 also needs to be provided with a pressing portion Y, the operation can refer to the side wall C of the first half shell 110, which is simple to manufacture and easy to operate. The stamping die head used for stamping can be prefabricated according to the side edge of the side wall C that needs to be bent.

[0033] In some embodiments, reference Figures 2 to 4, the side wall C is square, and the holding portion Y is located on the two opposite sides of the side wall C. In the present embodiment, the side wall C is square, and has four sides. The four sides of the side wall C correspond one by one to the four sides of the single-sided pole piece 210, respectively, and the holding portion Y is located on the two opposite sides of the side wall C. That is, when the side wall C is bent inward, the holding portion Y is formed on the two opposite sides thereof. Specifically, the cross-section of the side wall C is trapezoidal, and the holding portion Y corresponds to the waist of the trapezoid. When the laminated battery cell 200 is accommodated in the accommodation cavity R, the holding portions Y on the two opposite sides of the side wall C can correspond to the two opposite sides of the single-sided pole piece 210 to hold the single-sided pole piece 210, so as to keep the single-sided pole piece 210 in a flat state, and to achieve a tight fit on all sides in the laminated battery cell 200.

[0034] In some embodiments, the bending width of the pressing portion Y is 5 mm to 10 mm. In this embodiment, the bending width of the pressing portion Y can be set within the range of 5 mm to 10 mm. For example, the bending width of the pressing portion Y can be set to 5 mm, 7.5 mm or 10 mm. Optionally, the bending width of the pressing portion Y can be set with reference to the degree of warping of the single-sided pole piece 210. For example, when the degree of warping of the single-sided pole piece 210 is small, the bending width of the pressing portion Y can be set to 5 mm; when the degree of warping of the single-sided pole piece 210 is medium, the bending width of the pressing portion Y can be set to 7.5 mm; when the degree of warping of the single-sided pole piece 210 is large, the bending width of the pressing portion Y can be set to 10 mm.

[0035] In some embodiments, the bending depth of the pressing portion Y is 0.1 mm to 0.5 mm. In this embodiment, the bending depth of the pressing portion Y can be set within the range of 0.1 mm to 0.5 mm. For example, the bending depth of the pressing portion Y can be set to 0.1 mm, 0.3 mm or 0.5 mm. Optionally, the bending depth of the pressing portion Y can be set with reference to the degree of warping of the single-sided pole piece 210. For example, when the degree of warping of the single-sided pole piece 210 is small, the bending depth of the pressing portion Y can be set to 0.1 mm; when the degree of warping of the single-sided pole piece 210 is medium, the bending depth of the pressing portion Y can be set to 0.3 mm; when the degree of warping of the single-sided pole piece 210 is large, the bending depth of the pressing portion Y can be set to 0.5 mm.

[0036] In some embodiments, reference Figure 5, the outer surface of the side wall C is a horizontal plane, and the holding portion Y is convexly arranged on the inner surface of the side wall C. In this embodiment, a structural member may be arranged on the inner surface of the side wall C, so that the holding portion Y is formed by the structural member structure. When manufacturing the first half shell 110 or the second half shell 120, the structural member used to construct the holding portion Y is installed on the inner surface of the side wall C, so that it is convexly arranged on the inner surface of the side wall C. Optionally, the holding portion Y may be in the shape of a square frame and convexly arranged on the inner surface of the side wall C, the length of the holding portion Y is the same as the length of the single-sided pole piece 210, and the width of the holding portion Y is the same as the width of the single-sided pole piece 210. The thickness of the holding portion Y can be set according to actual conditions, and there is no limitation on this. In this way, the holding portion Y can hold each side of the single-sided pole piece 210, and can prevent the single-sided pole piece 210 from warping, so that the single-sided pole piece 210 can remain flat.

[0037] In some embodiments, the pressing portion Y is fixedly connected to the inner surface of the side wall C. Specifically, there are many ways to fix the pressing portion Y to the inner surface of the side wall C, such as welding fixation, adhesive fixation, etc., including but not limited to these. As an example, when the pressing portion Y is made of metal (such as aluminum metal), it can be welded and fixed to the inner surface of the side wall C. In this embodiment, by fixing the pressing portion Y to the inner surface of the side wall C, the pressing stability of the pressing portion Y on the single-sided pole piece 210 is ensured, thereby ensuring the flatness of the single-sided pole piece 210.

[0038] In some embodiments, reference Figure 5 , the pressing portion Y includes a first pressing portion Y and a second pressing portion Y in a strip shape, and the first pressing portion Y and the second pressing portion Y respectively press the opposite sides of the single-sided pole piece 210. In this embodiment, optionally, the length of the first pressing portion Y and the second pressing portion Y is the same as the side length of the opposite sides of the single-sided pole piece 210, and the width and thickness of the pressing portion Y can be set according to actual conditions, and there is no restriction on this. When the laminated battery cell 200 is placed in the accommodating cavity R, the first pressing portion Y and the second pressing portion Y protruding on the side wall C correspond to the opposite sides of the single-sided pole piece 210, which can prevent the single-sided pole piece 210 from warping, so that the single-sided pole piece 210 remains flat.

[0039] In some embodiments, reference Figure 2 , Figure 4 and Figure 5, the first half shell 110 and the second half shell 120 further include a peripheral wall Z for docking, the peripheral wall Z is arranged along the edge of the side wall C and has an angle with the side wall C. In this embodiment, in the first half shell 110 and the second half shell 120, the peripheral wall Z and the side wall C are integrally formed, and along the edge of the side wall C, the peripheral wall Z is arranged in the circumferential direction of the side wall C. Optionally, the angle between the peripheral wall Z and the side wall C is equal to or greater than 90°. The peripheral wall Z of the first half shell 110 and the peripheral wall Z of the second half shell 120 are adapted to each other, and the first half shell 110 and the second half shell 120 are docked to achieve the docking of the first half shell 110 and the second half shell 120. Optionally, after the peripheral wall Z of the first half shell 110 and the peripheral wall Z of the second half shell 120 are docked, they are hot-melt connected at the docking position to complete the packaging.

[0040] The utility model also provides a battery, referring to Figures 2 to 5 The battery comprises a battery housing 100 and a laminated battery cell 200 disposed in the battery housing 100. The laminated battery cell 200 has single-sided pole pieces 210 on two opposite sides thereof. The battery housing 100 is a battery housing as described in the above embodiment. The specific structure of the battery housing 100 is referred to the above embodiment. Since the battery adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0041] The above description is only a partial or preferred embodiment of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A battery casing for accommodating a laminated battery core, wherein the two opposite outermost layers of the laminated battery core are both single-sided pole pieces, characterized in that: The battery casing includes a first half shell and a second half shell that are butt-jointed with each other, and the first half shell and the second half shell are butt-jointed to form a housing cavity for accommodating the laminated battery cell, and the first half shell and the second half shell both include side walls opposite to the single-sided pole piece, and at least one of the side walls is provided with a pressing portion for pressing the side edge of the single-sided pole piece.

2. The battery housing according to claim 1, characterized in that: The pressing portion is formed by bending the side wall inwardly.

3. The battery housing according to claim 2, characterized in that: The side wall is square, and the pressing portions are located on two opposite sides of the side wall.

4. The battery casing according to claim 2 or 3, characterized in that: The bending width of the pressing portion is 5 mm to 10 mm.

5. The battery casing according to claim 2 or 3, characterized in that: The bending depth of the pressing portion is 0.1 mm to 0.5 mm.

6. The battery housing according to claim 1, characterized in that: The outer surface of the side wall is a horizontal plane, and the pressing portion is protruding from the inner surface of the side wall.

7. The battery housing according to claim 6, characterized in that: The pressing portion is fixedly connected to the inner surface of the side wall.

8. The battery casing according to claim 6 or 7, characterized in that: The pressing portion includes a first pressing portion and a second pressing portion in a strip shape, and the first pressing portion and the second pressing portion respectively press two opposite sides of the single-sided pole piece.

9. The battery housing according to claim 1, characterized in that: The first half shell and the second half shell further include a peripheral wall for butting against each other, wherein the peripheral wall is arranged along the edge of the side wall and has an angle with the side wall.

10. A battery, comprising a battery housing and a laminated battery core disposed in the battery housing, wherein two opposite sides of the laminated battery core respectively have single-sided pole pieces, characterized in that: The battery casing is the battery casing according to any one of claims 1 to 9.

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