Laminated battery cell, winding type battery cell and single battery

Abstract

The utility model belongs to the field of secondary batteries, and particularly relates to a laminated battery cell, a winding type battery cell and a single battery. In order to solve the technical problem that the cost is high due to the fact that a mylar film and a bottom support need to be adopted when a single battery is manufactured, the utility model provides a laminated battery cell, and at least one end of at least one diaphragm of the laminated battery cell extends out of a positive plate and a negative plate to form a film wrapping area wrapping non-tab areas of all the plates by at least one circle. The utility model further provides a winding type battery cell, wherein one end of a winding type battery cell diaphragm extends out of the positive pole piece and the negative pole piece to form a film wrapping area wrapping the non-tab areas of all the pole pieces for at least one circle. The utility model further provides a single battery with the film coating area. The size of the diaphragm is increased, the diaphragm is utilized to realize insulation between the battery cell and the shell, and meanwhile, one part of the diaphragm is fixed by the positive plate and the negative plate, so that a bottom support is not required to be additionally arranged to fix the diaphragm, a mylar film and the bottom support can be omitted, and the cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the field of secondary batteries, and in particular relates to a laminated battery core, a wound battery core and a single battery. Background Art

[0002] In most existing single cells (such as the single cells in the background technology section of the Chinese utility model patent with the authorization announcement number CN218919142U and the authorization announcement date of 2023.04.25), it is necessary to use Mylar film to package the battery cell (including wound battery cells and laminated battery cells), and use a bottom bracket to fix the Mylar film. Among them, the Mylar film is an insulating film, which is mainly divided into Kapton film, polypropylene film, polyester film and other types. The Mylar film is arranged between the battery shell and the battery cell to avoid short circuit between the positive and negative electrodes of the battery; the top surface of the bottom bracket is used to support the battery cell, and the bottom surface is hot-melt connected to the Mylar film, and part of the Mylar film is squeezed between the bottom bracket and the battery shell to fix the Mylar film.

[0003] In a single cell, the price of Mylar film and base is high, which leads to a high cost of the single cell. At the same time, the Mylar film and base need to be installed through a hot melt process. During the hot melt process, the Mylar film, base and plastic parts under the cover will produce additional products such as plastic drawing, plastic debris, and sharp plastic corners, which will affect the quality of the single cell. In addition, the hot melt process is technically complex and the equipment is expensive. Utility Model Content

[0004] The utility model aims to provide a laminated battery core to solve the technical problem of high cost caused by the need to use Mylar film and bottom bracket when manufacturing single battery.

[0005] The utility model also aims to provide a wound battery cell to solve the same technical problem as above.

[0006] The utility model also aims to provide a single battery to solve the same technical problem as above.

[0007] In order to achieve the above-mentioned purpose, the technical solution of the laminated battery cell provided by the utility model is:

[0008] A laminated battery cell comprises at least one positive electrode sheet and at least one negative electrode sheet, wherein a diaphragm is arranged between adjacent positive electrode sheets and negative electrode sheets, each electrode sheet has a tab and a non-tab area, and each diaphragm has an isolation portion located between the positive and negative electrode sheets to separate the non-tab areas of the positive and negative electrode sheets; at least one end of at least one diaphragm extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-tab areas of all electrode sheets for at least one circle.

[0009] Furthermore, there are more than two positive and negative electrode sheets, and the coating area is formed by one end of one of the separators.

[0010] Furthermore, there are more than two positive and negative electrode sheets, and the coating area is formed by two ends of one of the separators.

[0011] Furthermore, the ends of the ends of each separator extending outside the positive and negative electrode sheets are fixed by bonding or hot pressing.

[0012] The beneficial effects of the laminated battery cell of the utility model are as follows: the utility model is an invention that changes the relationship between elements. In the prior art, the diaphragm is entirely located between the positive electrode sheet and the negative electrode sheet; in the present battery cell, the size of at least one diaphragm is increased, and the corresponding diaphragm includes a portion extending from between the positive electrode sheet and the negative electrode sheet in addition to the isolation portion fixed between the positive electrode sheet and the negative electrode sheet. At the same time, after the diaphragm extends from between the positive electrode sheet and the negative electrode sheet, it wraps around all the electrode sheets at least once and forms an insulating layer (i.e., the coating area). When manufacturing a single cell, the portion of the diaphragm extending from between the positive electrode sheet and the negative electrode sheet can be used to insulate the battery cell from the shell, and at the same time, the isolation portion of the diaphragm is fixed by the positive electrode sheet and the negative electrode sheet, and there is no need to set up an additional bottom bracket to fix the diaphragm, thereby eliminating the Mylar film and the bottom bracket, and correspondingly eliminating the hot melt process, which can effectively reduce the cost of the single cell.

[0013] To achieve the above purpose, the technical solution of the wound battery cell provided by the utility model is:

[0014] A wound battery cell comprises a positive electrode sheet, a negative electrode sheet and a separator located between the positive electrode sheet and the negative electrode sheet, each electrode sheet has a tab and a non-tab area, the separator has an isolation part located between the positive and negative electrode sheets to separate the non-tab areas of the positive and negative electrode sheets, and one end of the separator extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-tab areas of all electrode sheets for at least one circle.

[0015] Furthermore, the end of the separator extending outside the positive and negative electrode sheets is fixed by bonding or hot pressing.

[0016] The beneficial effects of the wound battery cell of the utility model are as follows: the utility model is an invention that changes the relationship between elements. In the prior art, the diaphragm is entirely located between the positive electrode sheet and the negative electrode sheet; in the present battery cell, the size of the diaphragm is increased, and the diaphragm includes a package portion extending from between the positive electrode sheet and the negative electrode sheet in addition to the isolation portion fixed between the positive electrode sheet and the negative electrode sheet. At the same time, the diaphragm extends from between the positive electrode sheet and the negative electrode sheet and wraps around all the electrode sheets for at least one cycle to form an insulating layer. When manufacturing a single cell, the package portion of the diaphragm extending from between the positive electrode sheet and the negative electrode sheet can be used to achieve insulation between the battery cell and the shell, and at the same time, the isolation portion of the diaphragm is fixed by the positive electrode sheet and the negative electrode sheet, and there is no need to set up an additional bottom bracket to fix the diaphragm, thereby eliminating the Mylar film and the bottom bracket, and correspondingly eliminating the hot melt process, which can effectively reduce the cost of the single cell.

[0017] In order to achieve the above-mentioned purpose, the technical solution of the single cell provided by the utility model is:

[0018] A single cell battery comprises at least one battery cell and a shell, wherein all the battery cells are installed in the shell, the battery cell is a laminated battery cell, the laminated battery cell comprises at least one positive electrode sheet and at least one negative electrode sheet, a diaphragm is arranged between adjacent positive and negative electrode sheets, each electrode sheet has a tab and a non-tab area, each diaphragm has an isolating portion located between the positive and negative electrode sheets to separate the non-tab areas of the positive and negative electrode sheets; at least one end of at least one diaphragm extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-tab areas of all electrode sheets for at least one circle; or, the battery cell is a wound battery cell, the wound battery cell comprises a positive electrode sheet, a negative electrode sheet and a diaphragm located between the positive and negative electrode sheets, each electrode sheet has a tab and a non-tab area, the diaphragm has an isolating portion located between the positive and negative electrode sheets to separate the non-tab areas of the positive and negative electrode sheets, and one end of the diaphragm extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-tab areas of all electrode sheets for at least one circle.

[0019] Furthermore, when the battery cell is a laminated battery cell, there are more than two positive and negative electrode sheets, and the coating area is formed by one end of one of the separators.

[0020] Furthermore, when the battery cell is a laminated battery cell, there are more than two positive and negative electrode sheets, and the coating area is formed by two ends of one of the diaphragms.

[0021] Furthermore, when the battery cell is a laminated battery cell, the ends of each diaphragm extending outside the positive and negative electrode sheets are fixed by bonding or hot pressing.

[0022] Furthermore, when the battery cell is a wound battery cell, the end of the separator extending outside the positive and negative electrode sheets is fixed by bonding or hot pressing.

[0023] Furthermore, the single cell battery further includes a cover plate, the number of the battery cells is at least two, and the tabs of each battery cell are respectively fixedly connected to the cover plate.

[0024] Furthermore, the upper end of the shell is open, the cross-section of the shell is rectangular, the cover plate is welded and fixed to the shell, and the inner surfaces of the opposite side walls of the shell are provided with supporting steps for supporting the cover plate, and the outer peripheral surface of the cover plate is limitedly matched with the inner wall surface of the shell.

[0025] Furthermore, the number of the battery cells is at least two, and the battery cells are fixed as a whole by insulating tape.

[0026] The beneficial effects of the single cell battery of the utility model are as follows: the utility model is an improved invention. In the prior art, the diaphragm is entirely located between the positive electrode sheet and the negative electrode sheet; in the present single cell battery, the length dimension of at least one diaphragm is increased, and the diaphragm includes a coating area in addition to the portion located between the positive electrode sheet and the negative electrode sheet, and at the same time, the diaphragm extends from between the positive electrode sheet and the negative electrode sheet and wraps around all the electrode sheets for at least one cycle to form an insulating layer. When manufacturing a single cell battery, the coating area of ​​the diaphragm extending from between the positive electrode sheet and the negative electrode sheet can be used to achieve insulation between the battery cell and the shell, and at the same time, the isolation portion of the diaphragm is fixed between the positive electrode sheet and the negative electrode sheet, and there is no need to set up an additional base to fix the diaphragm, thereby eliminating the Mylar film and the base, which can effectively reduce the cost of the single cell battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a single battery of the utility model;

[0028] Figure 2 It is a structural schematic diagram of a wound-type battery cell of the utility model;

[0029] Figure 3 for Figure 2 Schematic diagram of the structure of the battery cell when it is not wound;

[0030] Figure 4 It is a structural schematic diagram of a laminated cell of a single cell of the utility model;

[0031] Figure 5 for Figure 4 The middle diaphragm is a schematic diagram of the structure when it is wound on the pole piece.

[0032] Description of reference numerals:

[0033] 1. Cover plate; 11. Negative pole; 12. Positive pole; 21. Negative electrode adapter; 22. Positive electrode adapter; 3. Wound battery cell; 31. Pure diaphragm area; 32. Diaphragm and pole piece mixed area; 4. Insulating tape; 5. Shell. DETAILED DESCRIPTION

[0034] In order to solve the problems in the background technology, the core inventive concept of the utility model is: since the diaphragm is also an insulating film (the diaphragm is an insulating film made of polyethylene, polypropylene and other materials), the diaphragm can be used instead of the Mylar film, thereby omitting the Mylar film. At the same time, a part of the diaphragm is fixed between the positive electrode sheet and the negative electrode sheet, so there is no need to set up an additional fixing structure, and the base for fixing the Mylar film can be omitted, thereby reducing the cost of the single battery.

[0035] The present invention is further described in detail below in conjunction with the embodiments.

[0036] The specific embodiment of the single battery provided by the utility model is as follows:

[0037] like Figure 1-5 As shown, the single cell is a square cell, and the single cell specifically includes a cover plate 1 (aluminum cover or stainless steel cover), a negative electrode adapter 21, a positive electrode adapter 22, at least one battery cell and a shell 5 (aluminum shell or stainless steel shell). Each battery cell includes a positive electrode sheet, a negative electrode sheet and a separator.

[0038] Among them, the battery cell is a laminated battery cell or a wound battery cell.

[0039] As a specific implementation method, refer to Figure 1-3 As shown, the battery cell is a wound battery cell 3, which includes a positive electrode sheet, a negative electrode sheet and a separator located between the positive electrode sheet and the negative electrode sheet, each electrode sheet has a pole ear and a non-pole ear area, the separator has an isolation part located between the positive and negative electrode sheets to separate the non-pole ear areas of the positive and negative electrode sheets, and one end of the separator extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-pole ear areas of all electrode sheets for at least one circle.

[0040] like Figure 2-3 As shown, the wound battery cell 3 includes a mixed area 32 of diaphragm and pole piece and a pure diaphragm area 31 (i.e., a coating area) consisting only of diaphragm. When manufacturing a single battery, the pure diaphragm area 31 serves as an insulating layer to achieve insulation between the battery cell and the housing 5.

[0041] Specifically, the end of the diaphragm of the wound battery cell that extends beyond the positive and negative electrode sheets can be fixed to itself by bonding with insulating tape or by hot pressing. Only the end of the diaphragm that extends beyond the positive and negative electrode sheets can be fixed, or the entire portion of the diaphragm that extends beyond the positive and negative electrode sheets can be fixed. The structure is simple. Of course, the end of the diaphragm that extends beyond the positive and negative electrode sheets can also be fixed to itself by hot melt adhesive bonding or the like. In this embodiment, there is no restriction on the specific fixing method.

[0042] In the prior art, the diaphragm is entirely located between the positive electrode sheet and the negative electrode sheet; in the present wound battery cell 3, the size of the diaphragm is increased, and in addition to the isolating portion fixed between the positive electrode sheet and the negative electrode sheet, the diaphragm also includes a wrapping portion extending from between the positive electrode sheet and the negative electrode sheet, and at the same time, after the diaphragm extends from between the positive electrode sheet and the negative electrode sheet, it wraps around all the electrode sheets for at least one cycle and forms an insulating layer. When manufacturing a single cell, the wrapping portion of the diaphragm extending from between the positive electrode sheet and the negative electrode sheet can be used to achieve insulation between the cell and the housing 5, and at the same time, the isolating portion of the diaphragm is fixed by the positive electrode sheet and the negative electrode sheet, and there is no need to set up an additional bottom bracket to fix the diaphragm, thereby eliminating the Mylar film and the bottom bracket, and correspondingly eliminating the hot melt process, which can effectively reduce the cost of the single cell.

[0043] In another specific embodiment, Figure 4-5As shown, each battery cell is a stacked battery cell, which includes at least one positive electrode sheet and at least one negative electrode sheet, and a separator is provided between adjacent positive and negative electrode sheets, each electrode sheet has a pole ear and a non-pole ear area, and each separator has an isolation portion located between the positive and negative electrode sheets to separate the non-pole ear areas of the positive and negative electrode sheets; at least one end of at least one separator extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-pole ear areas of all electrode sheets for at least one circle.

[0044] In the same laminated cell, only one end or both ends of one diaphragm may extend out of the positive and negative electrode sheets to form a membrane area; or one end or both ends of two diaphragms may extend out of the positive and negative electrode sheets to form a membrane area. Of course, there may also be a greater number of diaphragms extending out of the positive and negative electrode sheets. Of course, in a laminated cell, a common diaphragm having the same length as the non-ear area of ​​the electrode sheet may also be included. In this case, all the common diaphragms are located between the corresponding adjacent two electrode sheets.

[0045] like Figure 4-5 As shown, the laminated battery cell includes a mixed area 32 of diaphragm and electrode sheet and a pure diaphragm area 31. The pure diaphragm area 31 is formed by the diaphragm extending from between the positive electrode sheet and the negative electrode sheet. When manufacturing a single battery, the pure diaphragm area 31 is used as an insulating layer to achieve insulation between the battery cell and the housing 5.

[0046] Specifically, the portion of the diaphragm of the stacked battery cell that extends beyond the positive and negative electrode sheets can be fixed to itself, the remaining portion of the diaphragm that extends beyond the positive and negative electrode sheets, or to the electrode sheets by means of insulating tape, hot melt adhesive bonding process, or hot pressing process. Only the ends of the ends of the diaphragm that extend beyond the positive and negative electrode sheets can be fixed, or all of the portions of the diaphragm that extend beyond the positive and negative electrode sheets can be fixed. The structure is simple.

[0047] Of course, in different specific embodiments, in the laminated battery cell and the wound battery cell 3, the diaphragm can specifically wrap around all the pole pieces for one week, one and a half weeks, two weeks or other number of weeks. In this embodiment, there is no limitation on the number of battery cells and the number of weeks the diaphragm is wrapped around.

[0048] In order to simplify the structure, as a specific implementation method, Figure 5 As shown, in the laminated battery cell, there are more than two positive and negative electrode sheets, and the coating area is formed by one end of one of the diaphragms, and the structure is simple.

[0049] However, in other specific embodiments, refer to Figure 5 As shown, both ends of one of the diaphragms can extend from between the corresponding positive electrode sheet and the negative electrode sheet, and be fixed on itself after being wrapped around all the electrode sheets at least half a circle, so that all the diaphragms are wrapped around all the electrode sheets at least once and form an insulating layer (i.e., the coating area).

[0050] Of course, in other specific embodiments, one end or both ends of two, three or more separators may be extended from between the corresponding positive electrode sheet and the negative electrode sheet. In this embodiment, the number of separators and the length of each separator are not limited, as long as it can be ensured that all separators are wrapped around all the electrode sheets at least once to form a Figure 4 The pure diaphragm area 31 (ie, the insulating layer or the envelope area) shown in FIG.

[0051] In the prior art, the diaphragms are all located between the positive and negative electrodes; in the present laminated battery cell, the size of at least one diaphragm is increased, and the corresponding diaphragm includes a portion extending from between the positive and negative electrodes in addition to the isolation portion fixed between the positive and negative electrodes. At the same time, all corresponding diaphragms extend from between the positive and negative electrodes and wrap around all the electrodes for at least one cycle to form an insulating layer (i.e., a coating area). When manufacturing a single cell, the insulation between the cell and the housing 5 can be achieved by using part of the diaphragm, and at the same time, the isolation portion of the diaphragm is fixed by the positive and negative electrodes, and there is no need to set up an additional base to fix the diaphragm, thereby eliminating the Mylar film and the base, and correspondingly eliminating the hot melt process, which can effectively reduce the cost of the single cell.

[0052] In a single battery, the cover plate 1 is provided with structures such as a negative electrode column 11, a positive electrode column 12, an injection hole and an explosion-proof valve. The injection hole is used to inject electrolyte, the explosion-proof valve is used to prevent the battery from exploding, and the column is used to be electrically connected to the corresponding adapter. At the same time, the column needs to be tested for airtightness to ensure the airtightness of the cover plate 1.

[0053] In order to increase the total power of the single battery, as a specific implementation method, refer to Figure 1-3 As shown, the number of battery cells is at least two, and the pole ears of each battery cell are fixedly connected to the cover plate 1, so as to increase the total power of the single battery by increasing the number of battery cells. At this time, adjacent battery cells are insulated by a diaphragm extending from between the positive electrode sheet and the negative electrode sheet (i.e., the pure diaphragm area 31).

[0054] Of course, in other specific embodiments, the number of battery cells may also be one, three or more.

[0055] In order to facilitate processing and manufacturing, as a specific implementation method, refer to Figure 1 As shown, each pole ear is welded to the corresponding adapter, and each adapter is welded to the cover plate 1, which is convenient for processing and manufacturing. Specifically, the pole ear and the adapter are fixedly connected by ultrasonic welding or a composite process of ultrasonic welding and laser welding, and the adapter is fixedly connected to the pole on the housing 5 by laser welding.

[0056] However, in other specific implementations, the tabs, the corresponding adapter sheets and the cover plate 1 may also be bonded and fixed by conductive adhesive.

[0057] In order to improve the sealing performance of the single cell, as a specific implementation method, refer to Figure 1 As shown, the upper end of the shell 5 is open, and the cross section of the shell 5 is rectangular. Support steps for supporting the cover plate 1 are provided on the inner surfaces of the two opposite side walls of the shell 5, and the cover plate 1 is fixed to the shell 5 by laser welding process.

[0058] Specifically, the side wall of the shell 5 is divided into a large side wall with a larger area and a small side wall with a smaller area. The small side wall is thicker than the large side wall. The support step is set on the small side wall. After the cover plate 1 is installed on the support step, the outer peripheral surface of the cover plate 1 and the inner wall surface of the shell 5 are limited and matched. The cover plate 1 and the shell 5 are welded and connected by laser, thereby improving the sealing of the single battery. On the basis of omitting the Mylar film and the base, when the cover plate 1 and the shell 5 are welded and fixed, the Mylar film or the base can also be prevented from melting and producing plastic wire drawing, reducing the factors that need to be considered when welding the cover plate 1 and the shell 5, and improving the welding yield.

[0059] However, in other specific implementations, the supporting step may not be provided, but the lower surface of the cover plate 1 may be directly welded and fixed to the upper surface of the shell 5 .

[0060] In order to facilitate the assembly of single cells, as a specific implementation method, Figure 1 As shown, each battery cell is fixed as a whole by an insulating tape 4, so as to facilitate the assembly of single battery cells.

[0061] Specifically, when assembling a single battery, the following steps can be performed:

[0062] Step S1, welding and fixing each battery cell, the corresponding adapter sheet and the cover plate 1;

[0063] Step S2, using insulating tape 4 to fix the cells into a whole;

[0064] Step S3, putting all the battery cells together into the housing 5;

[0065] Step S4, welding and fixing the housing 5 and the cover plate 1.

[0066] It should be specially noted that, since the single cell battery in this embodiment has eliminated the bottom support, the battery cell actually lacks the support of the bottom support, so when the single cell battery in this embodiment is used in an environment with large vibration, the life of the single cell battery will be reduced, but it will not affect the normal use of the single cell battery, and it is only necessary to replace the single cell battery regularly; at the same time, it is recommended to use the single cell battery in this embodiment in a static, vibration-free or low-vibration environment.

[0067] Specific embodiments of the wound battery provided by the utility model:

[0068] The specific structure of the wound battery cell in this embodiment is the same as the structure of the wound battery cell in any specific implementation manner of the specific embodiment of the single battery embodiment of the utility model, and will not be repeated here.

[0069] The specific embodiment of the laminated battery provided by the utility model is as follows:

[0070] The specific structure of the laminated battery cell in this embodiment is the same as the structure of the laminated battery cell in any specific implementation manner of the specific embodiments of the single battery embodiment of the utility model, and will not be repeated here.

[0071] Finally, it should be noted that the above are only preferred embodiments of the utility model and are not intended to limit the utility model. Although the utility model is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A laminated battery cell, characterized in that: It includes at least one positive electrode sheet and at least one negative electrode sheet, and a diaphragm is arranged between adjacent positive electrode sheets and negative electrode sheets, each electrode sheet has a tab and a non-tab area, and each diaphragm has an isolation part located between the positive and negative electrode sheets to separate the non-tab areas of the positive and negative electrode sheets; at least one end of at least one diaphragm extends out of the positive and negative electrode sheets to form a coating area that surrounds the non-tab areas of all electrode sheets for at least one circle.

2. The laminated battery cell according to claim 1, characterized in that: There are more than two positive and negative electrode sheets, and the coating area is formed by one end of one of the separators.

3. The laminated battery cell according to claim 1, characterized in that: There are more than two positive and negative electrode sheets, and the coating area is composed of two ends of one of the diaphragms.

4. The laminated battery cell according to any one of claims 1 to 3, characterized in that: The ends of each separator extending outside the positive and negative electrode sheets are fixed by bonding or hot pressing.

5. A wound battery cell, characterized in that: The invention comprises a positive electrode sheet, a negative electrode sheet and a diaphragm located between the positive electrode sheet and the negative electrode sheet, each electrode sheet has a tab and a non-tab area, the diaphragm has an isolating portion located between the positive electrode sheet and the negative electrode sheet to separate the non-tab areas of the positive electrode sheet and the negative electrode sheet, and one end of the diaphragm extends out of the positive electrode sheet and the negative electrode sheet to form a coating area that surrounds the non-tab areas of all electrode sheets for at least one circle.

6. The wound battery cell according to claim 5, characterized in that: The end of the diaphragm extending outside the positive and negative electrode sheets is fixed by bonding or hot pressing.

7. A single battery, comprising at least one battery cell and a housing, wherein all the battery cells are installed in the housing, characterized in that: The battery cell is the battery cell described in any one of claims 1 to 6.

8. The single cell according to claim 7, characterized in that: The single cell battery also includes a cover plate. The number of the battery cells is at least two, and the tabs of each battery cell are respectively fixedly connected to the cover plate.

9. The single cell according to claim 8, characterized in that: The upper end of the shell is open, and the cross-section of the shell is rectangular. The cover plate is welded and fixed to the shell, and supporting steps for supporting the cover plate are provided on the inner surfaces of the opposite side walls of the shell, and the outer peripheral surface of the cover plate is limitedly matched with the inner wall surface of the shell.

10. The single cell according to claim 7, characterized in that: The number of the battery cells is at least two, and each battery cell is fixed as a whole by an insulating tape.

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