An irregularly shaped battery having a neck structure

Abstract

The utility model discloses a kind of special-shaped batteries with neck structure, it is related to lithium ion battery field.The special-shaped battery of the utility model includes outer package body, laminated electric core body and tab, there is a current collector non-coating area in the positive sheet and negative sheet of electric core body respectively, and there is coating on the both sides of current collector non-coating area respectively, two coating areas of each positive sheet and negative sheet form two electric core monomers after stacking, current collector non-coating area between two battery monomers has gap after stacking, can be mutually close, and form neck structure between two electric core monomers, to adapt to battery product with double-cavity structure communicated by through hole.The current collector non-coating area is separated by diaphragm, not easy to short-circuit under the collision of through hole, make the neck structure of battery have good security, two electric core monomers relative displacement, also not easy to breakage and damage, even adapt to double-cavity structure needing relative displacement.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion batteries, and in particular to an irregularly shaped battery with a neck structure. Background Technology

[0002] Currently, lithium-ion batteries, as energy storage components, are widely used in various electronic products. With the differentiated development across different application scenarios, electronic products have evolved into different types. These different application scenarios also place differentiated demands on the lithium-ion batteries used in these electronic products.

[0003] As people's demands for portability and battery life in electronic products continue to increase, there is a need for batteries with larger capacities, while the space available for battery design within electronic products is limited. Current lithium-ion batteries are generally rectangular; to fully utilize the space within electronic products, batteries need to be designed with irregular shapes to balance maximizing capacity and space constraints. For example, the battery design space inside an electronic product could be two cavities connected by a through-hole.

[0004] Therefore, existing technology typically places two independent batteries within the aforementioned dual-chamber configuration, and then connects the two batteries and the internal circuitry of the electronic product via wires. However, this approach increases the complexity of wiring and limits the utilization of product space.

[0005] Existing irregularly shaped batteries primarily employ a stacked structure, varying the width of the battery by altering the dimensions of the stacked electrodes. While these irregularly shaped batteries can be designed to pass through a through-hole and fill both cavities, the battery is relatively weak at the through-hole location, making the electrodes prone to misalignment during use, thus posing a risk of short circuits and damage. In particular, the dual-cavity structure of the aforementioned electronic products may require relative displacement during use, a requirement that existing irregularly shaped battery structures cannot meet.

[0006] Therefore, it is evident that the current irregular battery structure cannot be adapted to battery products with a dual-cavity structure connected by through holes. Utility Model Content

[0007] To address the problems existing in the prior art, the main objective of this utility model is to provide an irregularly shaped battery with a neck structure, which can be adapted to battery products with a dual-cavity structure connected by through holes, and the neck structure of the battery has good safety, and can even be adapted to dual-cavity structures that require relative displacement.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A non-circular battery with a neck structure includes an outer packaging body, a stacked cell body disposed within the outer packaging body, and tabs connected to the cell body and extending out of the outer packaging body. The cell body includes a positive electrode, a negative electrode, and a separator, wherein the positive and negative electrode sheets are alternately stacked with spacing between them by the separator. The positive electrode sheet includes a positive current collector, a first positive electrode coating, and a second positive electrode coating. The positive current collector has an uncoated area. The first positive electrode coating and the second positive electrode coating are respectively disposed on both sides of the uncoated area on the positive current collector. The negative electrode sheet includes a negative electrode current collector, a first negative electrode coating, and a second negative electrode coating. The negative electrode current collector has an uncoated negative electrode area, and the first negative electrode coating and the second negative electrode coating are respectively disposed on both sides of the uncoated negative electrode area on the negative electrode current collector. In the stacking direction of the positive and negative electrode sheets, the first positive electrode coating and the first negative electrode coating are stacked alternately, and the second positive electrode coating and the second negative electrode coating are stacked alternately. The diaphragm is also spaced between the uncoated positive electrode area and the uncoated negative electrode area, which are close to each other to form a neck structure with the cell body.

[0009] As an improvement, the outlines of each of the first negative electrode coatings form similar shapes, each of the first negative electrode coatings is reduced in size along a stacking direction by a preset ratio, the outline of the first positive electrode coating is similar to the outline of the first negative electrode coating, and the outline ratio of the first positive electrode coating is less than or equal to the outline ratio of the upper first negative electrode coating. The outlines of each of the second negative electrode coatings form similar shapes, and each of the second negative electrode coatings is reduced in size according to a preset ratio along a stacking direction. The outlines of the second positive electrode coating and the second negative electrode coating form similar shapes, and the outline ratio of the second positive electrode coating is less than or equal to the outline ratio of the upper second negative electrode coating.

[0010] As an improvement, each of the first negative electrode coatings is reduced in size by a preset ratio above the stacking direction, and each of the first negative electrode coatings is reduced in size by a preset ratio below the stacking direction; each of the second negative electrode coatings is reduced in size by a preset ratio above the stacking direction, and each of the second negative electrode coatings is reduced in size by a preset ratio below the stacking direction.

[0011] As an improved embodiment, each of the first negative electrode coating and the first positive electrode coating has a circular outline and is alternately stacked in a spherical shape under the separator spacing; each of the second negative electrode coating and the second positive electrode coating has a circular outline and is alternately stacked in a spherical shape under the separator spacing.

[0012] As an improvement, the outline dimension of the first negative electrode coating in each negative electrode sheet is smaller than the outline dimension of the second negative electrode coating in the same negative electrode sheet, and the outline dimension of the first positive electrode coating in each positive electrode sheet is smaller than the outline dimension of the second positive electrode coating in the same positive electrode sheet.

[0013] As an improvement, the uncoated positive electrode areas facing the first positive electrode coating and the second positive electrode coating are respectively configured as expansion structures, and the uncoated negative electrode areas facing the first negative electrode coating and the second negative electrode coating are respectively configured as expansion structures.

[0014] As an improved solution, the positive electrode sheet is wrapped between two separators, and the two separators are connected by their edges to form a separator bag. The first positive electrode coating and the second positive electrode coating are respectively coated on both sides of the positive electrode current collector.

[0015] As an improvement, there are two or more positive and negative electrodes, with the number of negative electrodes being one more layer than the number of positive electrodes.

[0016] As an improvement, the first and second negative electrode coatings in the topmost and bottommost negative electrode sheets are coated on one side, while the first and second negative electrode coatings in the remaining negative electrode sheets are coated on both sides.

[0017] As an improvement, each of the positive electrode plates has a positive electrode handle on its positive electrode current collector, and each positive electrode handle is welded to an electrode tab; each of the negative electrode plates has a negative electrode handle on its negative electrode current collector, and each negative electrode handle is welded to an electrode tab.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: In this invention, an uncoated current collector area is provided on both the positive and negative electrode plates of the battery cell body, and a coating is provided on both sides of the uncoated current collector area. The two coated areas of each positive and negative electrode plate are stacked to form two battery cells. The uncoated current collector areas between the two battery cells have a gap after stacking, allowing them to approach each other and forming a neck structure between the two battery cells. This adapts to battery products with a dual-cavity structure connected by through-holes. The uncoated current collector areas are separated by a separator, making them less prone to short circuits due to collisions with the through-holes. This provides good safety for the battery's neck structure. The relative displacement of the two battery cells also makes them less prone to breakage and damage, even adapting to dual-cavity structures requiring relative displacement.

[0019] The present invention will be further described below with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 A three-dimensional structural diagram of an irregularly shaped battery according to an embodiment of the present invention; Figure 2 A schematic diagram of the front view structure of the negative electrode sheet of the irregularly shaped battery according to an embodiment of the present invention; Figure 3 A schematic diagram of the front structure of the positive electrode sheet of the irregularly shaped battery according to an embodiment of the present invention; Figure 4 A schematic diagram of the main structure of the positive electrode bag of the irregularly shaped battery according to an embodiment of the present invention; Figure 5 A three-dimensional structural diagram of the stacking method of the irregularly shaped battery cell body according to an embodiment of the present invention; Figure 6 A cross-sectional schematic diagram of the stacked structure of the cell body of the irregularly shaped battery according to an embodiment of the present invention. Figure 7 A cross-sectional schematic diagram of an irregularly shaped battery according to an embodiment of the present invention.

[0021] Reference numerals: 10, outer packaging; 20, cell body; 21, neck structure; 30, tab; 40, positive electrode plate; 41, positive current collector; 42, first positive electrode coating; 43, second positive electrode coating; 44, uncoated area of ​​positive electrode; 45, positive electrode handle; 50, negative electrode plate; 51, negative electrode current collector; 52, first negative electrode coating; 53, second negative electrode coating; 54, uncoated area of ​​negative electrode; 55, negative electrode handle; 61, diaphragm bag. Detailed Implementation

[0022] To better illustrate the purpose, technical solution, and advantages of this utility model, the specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0023] It should be noted that when a component / part is referred to as being "set on" another component / part, it can be directly set on the other component / part or there may be an intervening component / part. When a component / part is referred to as being "connected / linked" to another component / part, it can be directly connected / linked to the other component / part or there may be an intervening component / part. The term "connected / linked" as used herein can include electrical and / or mechanical physical connections / links. The term "including / comprises" as used herein means the presence of a feature, step, or component / part, but does not exclude the presence or addition of one or more other features, steps, or components / parts. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. Furthermore, in the description of this application, the terms "first," "second," etc., are used for descriptive purposes and to distinguish similar objects only; there is no order between them, nor should they be construed as indicating or implying relative importance. Additionally, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0025] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0026] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0027] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0028] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0029] like Figures 1 to 7 As shown, an irregularly shaped battery with a neck structure includes an outer packaging body 10, a stacked cell body 20 disposed within the outer packaging body 10, and tabs 30 connected to the cell body 20 and extending outside the outer packaging body 10. The cell body 20 includes a positive electrode 40, a negative electrode 50, and a separator. (Reference) Figure 3 and Figure 4 The positive electrode 40 is wrapped between two separators, which are connected by their edges to form a separator bag 61. The positive electrode 40 and the negative electrode 50 wrapped in the separator bag 61 are stacked alternately, so that each positive electrode 40 is stacked between two negative electrode 50 after being separated by the separators.

[0030] For the purposes of this application, reference is made to Figure 3 and Figure 4The positive electrode 40 includes a positive current collector 41, a first positive electrode coating 42, and a second positive electrode coating 43. The positive current collector 41 has an uncoated positive electrode region 44. The first positive electrode coating 42 and the second positive electrode coating 43 are respectively disposed on both sides of the uncoated positive electrode region 44 on the positive current collector 41. (Reference) Figure 2 The negative electrode sheet 50 includes a negative electrode current collector 51, a first negative electrode coating 52, and a second negative electrode coating 53. The negative electrode current collector 51 has an uncoated negative electrode area 54. The first negative electrode coating 52 and the second negative electrode coating 53 are respectively disposed on both sides of the uncoated negative electrode area 54 on the negative electrode current collector 51. (Reference) Figures 5 to 7 In the stacking direction of the positive electrode 40 and the negative electrode 50, the first positive electrode coating 42 and the first negative electrode coating 52 are stacked alternately, and the second positive electrode coating 43 and the second negative electrode coating 53 are stacked alternately. The separator bag 61 also includes an uncoated positive electrode region 44. Thus, the uncoated positive electrode region 44 and the uncoated negative electrode region 54 are also separated by a separator. The uncoated positive electrode region 44 and the uncoated negative electrode region 54 are brought close together to form a neck structure 21 with the cell body 20.

[0031] Thus, each positive electrode 40 has a positive uncoated region 44 on its positive current collector 41, and a first positive coating 42 and a second positive coating 43 separated by the positive uncoated region 44. Each negative electrode 50 has a negative uncoated region 54 on its negative current collector 51, and a first negative coating 52 and a second negative coating 53 separated by the negative uncoated region 54. The first positive coating 42, the second positive coating 43, and the positive uncoated region 44 of each positive electrode 40 are all enclosed within a separator bag 61. After the positive electrode 40 and negative electrode 50 are alternately stacked, the alternating first positive coating 42 and first negative coating 52 will form one battery cell, and the alternating second positive coating 43 and second negative coating 53 will form another battery cell. The two battery cells are connected through the alternating positive uncoated region 44 and negative uncoated region 54. Since the positive electrode uncoated area 44 and the negative electrode uncoated area 54 have no coating, their thickness is thinner than that of the positive electrode coating or the negative electrode coating. There is a gap between the positive electrode uncoated area 44 and the negative electrode uncoated area 54, which can be compressed and brought closer together in the stacking direction, thereby forming a neck structure 21 that is thinner than the two individual cells after hot pressing and packaging.

[0032] Therefore, the irregularly shaped battery of this application can form a neck structure 21 between two individual cells, thus adapting to battery products with a dual-cavity structure connected by through holes. The uncoated area of ​​the current collector is separated by a separator, making it less prone to short circuits due to collisions with the through holes. This gives the battery's neck structure 21 good safety. The relative displacement of the two individual cells is also less likely to cause breakage or damage, and it is even suitable for dual-cavity structures that require relative displacement.

[0033] refer to Figure 6 and Figure 7 Specifically, in this embodiment, the outlines of each first negative electrode coating 52 are similar in shape, and each first negative electrode coating 52 is reduced in size along a stacking direction by a preset ratio. The outline of the first positive electrode coating 42 is similar in shape to the outline of the first negative electrode coating 52, and the outline ratio of the first positive electrode coating 42 is less than or equal to the outline ratio of the upper first negative electrode coating 52. The outlines of each second negative electrode coating 53 are similar in shape, and each second negative electrode coating 53 is reduced in size along a stacking direction by a preset ratio. The outline of the second positive electrode coating 43 is similar in shape to the outline of the second negative electrode coating 53, and the outline ratio of the second positive electrode coating 43 is less than or equal to the outline ratio of the upper second negative electrode coating 53.

[0034] refer to Figure 6 and Figure 7 Furthermore, each first negative electrode coating 52 is reduced in size by a preset ratio along the upper part of the stacking direction, and each first negative electrode coating 52 is reduced in size by a preset ratio along the lower part of the stacking direction. Similarly, each second negative electrode coating 53 is reduced in size by a preset ratio along the upper part of the stacking direction, and each second negative electrode coating 53 is reduced in size by a preset ratio along the lower part of the stacking direction. Thus, the two individual battery cells formed by the battery cell body 20 are each of irregularly shaped structures, adapting to the power supply installation space of irregularly shaped electronic products.

[0035] refer to Figure 6 and Figure 7 Specifically, in this embodiment, each of the first negative electrode coatings 52 and the first positive electrode coating 42 has a circular outline and is alternately stacked in a spherical shape under the separator spacing. Each of the second negative electrode coatings 53 and the second positive electrode coating 43 has a circular outline and is alternately stacked in a spherical shape under the separator spacing. Therefore, the proportions of the first negative electrode coating 52 and the first positive electrode coating 42 near the center are close to those of the largest first negative electrode coating 52 and the first positive electrode coating 42 in the center, while the proportions of the first negative electrode coating 52 and the first positive electrode coating 42 farther from the center are significantly different from those of the largest first negative electrode coating 52 and the first positive electrode coating 42 in the center. Thus, the cell body 20 will form two approximately spherical cell units, adapting to the double-spherical power supply mounting space of electronic products.

[0036] refer to Figure 6 and Figure 7 Furthermore, the outline dimension of the first negative electrode coating 52 in each negative electrode 50 is smaller than the outline dimension of the second negative electrode coating 53 of the same negative electrode 50, and the outline dimension of the first positive electrode coating 42 in each positive electrode 40 is smaller than the outline dimension of the second positive electrode coating 43 of the same positive electrode 40. Thus, the cell body 20 will form a large single cell and a smaller single cell, adaptable to the power supply installation space of a gourd-shaped electronic product.

[0037] refer to Figures 2 to 4Specifically, in this embodiment, the uncoated positive electrode areas 44 facing the first positive electrode coating 42 and the second positive electrode coating 43 are respectively configured as expansion structures, and the uncoated negative electrode areas 54 facing the first negative electrode coating 52 and the second negative electrode coating 53 are respectively configured as expansion structures. Thus, by expanding the structures to both sides, a narrower shape is formed in the middle, so that the irregular battery has a neck structure 21 not only in the stacking direction, but also in the vertical direction of the stacking, forming an annular neck mechanism as a whole.

[0038] refer to Figure 6 and Figure 7 In this embodiment, specifically, there are two or more positive electrode sheets 40 and negative electrode sheets 50, with one more negative electrode sheet 50 than positive electrode sheets 40. The first negative electrode coating 52 and the second negative electrode coating 53 in the uppermost and lowermost negative electrode sheets 50 are single-sided coated, while the first negative electrode coating 52 and the second negative electrode coating 53 in the remaining negative electrode sheets 50 are double-sided coated. The first positive electrode coating 42 and the second positive electrode coating 43 are coated on both sides of the positive current collector 41. Thus, both the uppermost and lowermost negative electrode sheets 50 have a single-sided negative electrode coating structure, effectively reducing the thickness of the cell body 20. The double-sided coated positive electrode sheet 40 and the middle double-sided negative electrode sheet 50 form a symmetrical conductive network, alleviating the problem of edge current concentration, while the outer single-sided negative electrode sheet 50 can suppress local polarization at the coating-current collector interface.

[0039] Specifically, in this embodiment, each positive electrode sheet 40 has a positive electrode handle 45 on the side of its positive electrode current collector 41 near the first positive electrode coating 42. The projections of each positive electrode handle 45 in the stacking direction coincide, allowing them to be welded together and connected to a tab 30. Similarly, each negative electrode sheet 50 has a negative electrode handle 55 on the side of its negative electrode current collector 51 near the first negative electrode coating 52. The projections of each negative electrode handle 55 in the stacking direction coincide, allowing them to be welded together and connected to a tab 30. Thus, the two tabs 30 can lead out the positive and negative electrodes of the cell body 20, which has two individual cells.

[0040] The above embodiments mainly describe the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A non-circular battery with a neck structure, comprising an outer packaging body (10), a stacked cell body (20) disposed within the outer packaging body (10), and tabs (30) connected to the cell body (20) and extending outside the outer packaging body (10), wherein the cell body (20) comprises a positive electrode (40), a negative electrode (50), and a separator, wherein the positive electrode (40) and the negative electrode (50) are alternately stacked at intervals between the separator, characterized in that: The positive electrode sheet (40) includes a positive electrode current collector (41), a first positive electrode coating (42), and a second positive electrode coating (43). The positive electrode current collector (41) has an uncoated positive electrode area (44). The first positive electrode coating (42) and the second positive electrode coating (43) are respectively disposed on both sides of the uncoated positive electrode area (44) on the positive electrode current collector (41). The negative electrode sheet (50) includes a negative electrode current collector (51), a first negative electrode coating (52), and a second negative electrode coating (53). The negative electrode current collector (51) has an uncoated negative electrode area (54). The first negative electrode coating (52) and the second negative electrode coating (53) are respectively disposed on both sides of the uncoated negative electrode area (54) on the negative electrode current collector (51). In the stacking direction of the positive electrode (40) and the negative electrode (50), the first positive electrode coating (42) and the first negative electrode coating (52) are stacked alternately, and the second positive electrode coating (43) and the second negative electrode coating (53) are stacked alternately. The diaphragm is also spaced between the uncoated positive electrode area (44) and the uncoated negative electrode area (54), and the uncoated positive electrode area (44) and the uncoated negative electrode area (54) are close to each other to form a neck structure (21) with the cell body (20).

2. The irregularly shaped battery with a neck structure according to claim 1, characterized in that: The outlines of each of the first negative electrode coatings (52) form similar shapes. Each of the first negative electrode coatings (52) is reduced in a preset ratio along a stacking direction. The outlines of the first positive electrode coating (42) and the first negative electrode coating (52) form similar shapes. The outline ratio of the first positive electrode coating (42) is less than or equal to the outline ratio of the upper first negative electrode coating (52). The outlines of each of the second negative electrode coatings (53) form similar shapes. Each of the second negative electrode coatings (53) is reduced in a preset ratio along a stacking direction. The outline of the second positive electrode coating (43) forms similar shapes to the outline of the second negative electrode coating (53). The outline ratio of the second positive electrode coating (43) is less than or equal to the outline ratio of the upper second negative electrode coating (53).

3. The irregularly shaped battery with a neck structure according to claim 1, characterized in that: Each of the first negative electrode coatings (52) is reduced in size by a preset ratio along the upper part of the stacking direction, and each of the first negative electrode coatings (52) is reduced in size by a preset ratio along the lower part of the stacking direction; Each of the second negative electrode coatings (53) is reduced in size by a preset ratio along the upper part of the stacking direction, and each of the second negative electrode coatings (53) is reduced in size by a preset ratio along the lower part of the stacking direction.

4. The irregularly shaped battery with a neck structure according to claim 1, characterized in that: Each of the first negative electrode coating (52) and the first positive electrode coating (42) has a circular outline and is stacked alternately in a spherical shape under the membrane spacing; each of the second negative electrode coating (53) and the second positive electrode coating (43) has a circular outline and is stacked alternately in a spherical shape under the membrane spacing.

5. A non-circular battery with a neck structure according to claim 1, characterized in that: The outline size of the first negative electrode coating (52) in each negative electrode (50) is smaller than the outline size of the second negative electrode coating (53) of the negative electrode (50), and the outline size of the first positive electrode coating (42) in each positive electrode (40) is smaller than the outline size of the second positive electrode coating (43) of the positive electrode (40).

6. A non-circular battery with a neck structure according to claim 1, characterized in that: The uncoated positive electrode regions (44) facing the first positive electrode coating (42) and the second positive electrode coating (43) are respectively configured as expansion structures, and the uncoated negative electrode regions (54) facing the first negative electrode coating (52) and the second negative electrode coating (53) are respectively configured as expansion structures.

7. A non-circular battery with a neck structure according to claim 1, characterized in that: The positive electrode sheet (40) is wrapped between two separators, and the two separators are connected by their edges to form a separator bag (61). The first positive electrode coating (42) and the second positive electrode coating (43) are respectively coated on both sides of the positive electrode current collector (41).

8. A non-circular battery with a neck structure according to claim 1, characterized in that: The positive electrode (40) and the negative electrode (50) are provided in more than two forms, and the number of negative electrode (50) is one more layer than the number of positive electrode (40).

9. A non-circular battery with a neck structure according to claim 1, characterized in that: The first negative electrode coating (52) and the second negative electrode coating (53) in the topmost negative electrode sheet (50) and the bottommost negative electrode sheet (50) are coated on one side, while the first negative electrode coating (52) and the second negative electrode coating (53) in the remaining negative electrode sheets (50) are coated on both sides.

10. A non-circular battery with a neck structure according to claim 1, characterized in that: Each of the positive electrode plates (40) has a positive electrode handle (45) on its positive electrode current collector (41), and each positive electrode handle (45) is welded to a tab (30); each of the negative electrode plates (50) has a negative electrode handle (55) on its negative electrode current collector (51), and each negative electrode handle (55) is welded to a tab (30).

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