Sealing assembly, single battery shell component and single battery

Abstract

The utility model belongs to the field of batteries, and particularly relates to a sealing assembly, a single battery shell component and a single battery. The sealing assembly comprises a protective cap and a dissolving film layer; the protective cap comprises an annular side wall and a bottom plate; the annular side wall is used for being fixed to a single battery shell component area on the periphery of the open hole, the bottom plate is located in an inner cavity of the single battery shell, and a cavity of the protective cap serves as a dissolving film layer containing cavity; the dissolving film layer is fixed in the dissolving film layer accommodating cavity, so that the dissolving film layer accommodating cavity is expanded, the annular side wall of the protective cover cap is extruded to be attached to the single battery shell component area on the periphery of the open hole, and the open hole is sealed; the protective cap is made of an elastic electrolyte-insoluble material, and the dissolving film layer is made of an electrolyte-soluble material. And before the dissolving film layer is dissolved, the protective cap is not easy to fall off, so that the installation reliability of the whole sealing assembly is relatively high. In the unpacking process, under the action of the electrolyte, the dissolving film layer is dissolved, the protective cap falls off, and the unpacking process is simple and reliable.

Description

Technical Field

[0001] The utility model belongs to the field of batteries, in particular to a sealing component, a single battery shell component and a single battery. Background Art

[0002] Currently, many single cells are connected in parallel or in series on the market to form large-capacity batteries (also called battery modules or battery packs).

[0003] However, the individual cells in existing large-capacity batteries are different from each other. Due to the existence of the barrel effect, they are often affected by the cell with the worst performance, which greatly limits the capacity limit and cycle times of the entire large-capacity battery. Therefore, how to improve the uniformity of each cell in a large-capacity battery has become the focus and difficulty of research in this field.

[0004] In order to solve the above problems, Chinese patent CN220324596U discloses a large-capacity battery, the structure of which is as follows Figure 1 As shown, such a large-capacity battery includes a housing 01 and a plurality of single cells 001, wherein the plurality of single cells 001 are connected in parallel in sequence and arranged in the inner cavity of the housing 01; the housing 01 is provided with a shared chamber (the shared chamber described here is an electrolyte shared chamber 02 and / or a gas shared chamber 03), and the shared chamber is connected to the inner cavities of each single cell. The electrolyte and / or gas in the inner cavities of each single cell are connected through the electrolyte shared chamber and / or the gas shared chamber, so that the electrolyte and / or gas of all single cells are in the same system, reducing the differences between the single cells, and improving the consistency between the single cells to a certain extent, thereby improving the cycle life of the large-capacity battery to a certain extent.

[0005] Usually, the shared chamber can be connected to the inner cavities of all the single cells by opening the sealing component sealed at the opening of the single cell housing. Specifically, the sealing component can be opened by external force or the electrolyte itself to complete the unpacking. The sealing component can be a sealing film that is soluble in electrolyte as disclosed in Chinese patent CN218525645U.

[0006] Although the above patent discloses that the sealing assembly is composed of a dissolving film and a protective film, and the protective film is located on the side of the dissolving film facing the inside of the single cell housing; when the dissolving film is dissolved in the electrolyte, the protective film falls off. However, there is no detailed introduction to the dissolving film and the protective film and the specific installation method of the dissolving film and the protective film and the single cell housing. Therefore, how to ensure the reliable installation, sealing performance and smooth opening of the sealing assembly is a technical problem that needs to be solved urgently. Utility Model Content

[0007] The utility model aims to provide a sealing assembly, a single cell housing component and a single cell. The sealing assembly and the single cell housing can be reliably installed and have good sealing performance, and can be opened smoothly by using electrolyte.

[0008] The technical solution of the utility model is to provide a sealing assembly, which is special in that it is used to seal the opening on the shell component of the single battery, and comprises a protective cap and a dissolving film layer;

[0009] The protective cap includes an annular side wall and a bottom plate; the annular side wall is used to be fixed to the single cell housing component area around the opening, the bottom plate is located in the inner cavity of the single cell housing, and the cavity of the protective cap serves as a dissolving film layer accommodating cavity;

[0010] The dissolving film layer is fixed in the dissolving film layer containing cavity, so that the dissolving film layer containing cavity is expanded, and the annular side wall of the extruded protective cap is fitted with the single cell housing component area around the opening, thereby sealing the opening;

[0011] The material of the protective cap is an elastic material that is insoluble in electrolyte, and the material of the dissolving film layer is an electrolyte soluble material.

[0012] The utility model fixes an elastic protective cap to a region of a single cell shell component around an opening, and fills a dissolving film layer in a cavity of the protective cap. Based on the support of the dissolving film layer, the protective cap is deformed and tightly fits with a region of a single cell shell component around the opening to seal the opening. At the same time, the electrolyte in the inner cavity of the single cell shell is in direct contact with the protective cap, but cannot be in contact with the dissolving film located in the cavity of the protective cap. Therefore, during the assembly process of large-capacity batteries (before unpacking), the openings of each single cell have better sealing performance. Before the dissolving film layer is dissolved, the protective cap is not easy to fall off, so that the installation reliability of the entire sealing assembly is higher. During the unpacking process, electrolyte is injected into the shared chamber. Under the action of the electrolyte, the dissolving film layer is dissolved, and the protective cap falls off from the single battery shell component, thereby connecting the inner cavity of each single battery shell with the inner cavity of the shared chamber, and the unpacking process is simple and reliable. In addition, the utility model uses the dissolving film layer as a mechanism for fixing the protective cap, and there is no need to introduce an additional fixing mechanism for the sealing component, so that the overall structure of the sealing component is simple and the manufacturing cost is low.

[0013] Furthermore, a first annular groove is formed on the outer surface of the annular side wall of the protective cap along its circumference. The first annular groove cooperates with the single cell housing component area around the opening, which can further improve the sealing performance of the protective cap on the opening.

[0014] Furthermore, a second annular groove is provided along its circumference on the inner surface of the annular side wall of the protective cap; the dissolving film layer is provided with an annular protrusion embedded in the second annular groove, and based on the cooperation between the second annular groove and the annular protrusion, the dissolving film layer can be stably fixed in the inner cavity of the protective cap.

[0015] Furthermore, the material of the dissolving film layer is PS, PMMA, SMMA, TPU, ABS, POM, PA6, PA12 or PVC.

[0016] Furthermore, the material of the protective cap is PP or EPDM rubber.

[0017] The utility model also provides a single cell housing component, which is special in that an opening penetrating the inner cavity of the single cell housing is provided on the single cell housing component, and the sealing component is fixed to the single cell housing component area around the opening.

[0018] The utility model also provides a single cell battery, which is special in that it comprises the above-mentioned single cell battery shell component.

[0019] The beneficial effects of the utility model are:

[0020] 1. The sealing components have high installation reliability and good sealing performance;

[0021] The utility model fixes an elastic protective cap to a region of a single cell shell component around an opening, and fills a dissolving film layer in a cavity of the protective cap. Based on the support of the dissolving film layer, the protective cap is deformed and tightly fits with a region of a single cell shell component around the opening to seal the opening. At the same time, the electrolyte in the inner cavity of the single cell shell is in direct contact with the protective cap, but cannot be in contact with the dissolving film located in the cavity of the protective cap. Therefore, during the assembly process of large-capacity batteries (before unpacking), the openings of each single cell have better sealing performance. Before the dissolving film layer is dissolved, the protective cap is not easy to fall off, so that the installation reliability of the entire sealing assembly is higher.

[0022] 2. The sealing component is easy to open;

[0023] During the unpacking process, electrolyte is injected into the shared chamber. Under the action of the electrolyte, the dissolving film layer is dissolved, and the protective cap falls off from the single battery shell component, thereby connecting the inner cavity of each single battery shell with the inner cavity of the shared chamber, and the unpacking process is simple and reliable;

[0024] 3. Simple structure;

[0025] The utility model uses the dissolving film layer as a mechanism for fixing the protective cap, and does not need to introduce an additional fixing mechanism of the sealing component, so that the overall structure of the sealing component is simple and the manufacturing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a large-capacity battery in the background technology;

[0027] Figure 2 This is a schematic diagram of the structure of the lower cover plate of the single cell in Example 1;

[0028] Figure 3 It is a schematic diagram of the partial structure of the lower cover plate of the single cell in Example 1;

[0029] Figure 4 It is a partial cross-sectional view of the lower cover plate of the single cell in Example 1 (without the sealing assembly fixed);

[0030] Figure 5 This is an exploded view of the lower cover plate of the single cell in Example 1;

[0031] Figure 6 This is a schematic diagram of the structure of the protective cap in Example 1;

[0032] Figure 7 is a cross-sectional view of the protective cap in Example 1;

[0033] Figure 8 It is a partial cross-sectional view of the cooperation between the protective cap and the lower cover plate of the single cell in Example 1;

[0034] Fig. 9 It is a partial cross-sectional view of the lower cover plate of the single cell in Example 1;

[0035] Fig.10 is a schematic diagram of the structure of a single cell in Example 1;

[0036] Fig.11 This is a schematic diagram of the structure of a single cell after the dissolving film layer in Example 1 is dissolved;

[0037] Fig.12 It is a partial cross-sectional view of a single cell after the dissolving film layer in Example 1 is dissolved;

[0038] Fig.13 It is a partial cross-sectional view of the upper cover plate of the single cell in Example 2;

[0039] Fig.14 is a schematic diagram of the structure of a single cell in Example 2;

[0040] The accompanying drawings in the figure are marked as follows:

[0041] 01. Shell; 02. Electrolyte shared chamber; 03. Gas shared chamber; 001. Single cell;

[0042] 1. Cover plate body; 11. Opening; 2. Sealing assembly; 21. Protective cap; 211. Annular side wall; 212. Bottom plate; 213. First annular groove; 214. Second annular groove; 215. Dissolving film layer accommodating cavity; 22. Dissolving film layer; 3. Pole. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary persons in the field without creative work should fall within the scope of protection of the utility model.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper, lower" etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second, etc." are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0046] The utility model provides a sealing component, wherein the sealing component is used to be fixed on a single cell shell component to seal an opening on the single cell shell component and communicated with the inner cavity of the single cell shell. At the same time, the sealing component can also fall off from the single cell shell component under the action of external electrolyte to open the opening.

[0047] It should be noted that:

[0048] 1. The single cell battery described here is a square shell battery, including an upper cover plate, a lower cover plate, a cylinder, a battery cell assembly and an electrolyte; the upper cover plate or the lower cover plate and the cylinder can be formed in one piece. The battery cell assembly described here can be called an electrode assembly, which is arranged in sequence by a positive electrode, a diaphragm, and a negative electrode, and is assembled by a lamination or winding process. The upper cover plate, the cylinder, and the lower cover plate constitute the shell of the single cell battery, and the battery cell assembly and the electrolyte are located in the shell of the single cell battery.

[0049] 2. In the present invention, the battery cell assembly described herein may also be a commercially available square shell battery with through holes.

[0050] 3. The single cell housing member described herein may be a single cell housing, or may be a partial structure of a single cell housing, such as at least one of a single cell upper cover plate, a single cell lower cover plate, or a single cell cylinder.

[0051] 4. The external electrolyte mentioned above refers to the electrolyte outside the shell of the single cell, not the electrolyte in the inner cavity of the single cell. That is to say, the sealing component cannot be opened through the electrolyte in the inner cavity of the single cell.

[0052] The utility model also provides a single battery housing component having the sealing assembly.

[0053] The utility model also discloses a single cell battery having the above-mentioned single cell battery shell component, wherein an opening penetrating the inner cavity of the single cell battery shell is provided on the single cell battery shell component, and a sealing component is fixed at the opening to seal the opening; under the action of an external electrolyte (an electrolyte located outside the single cell battery shell), a part of the structure of the sealing component is dissolved, causing it to fall off from the single cell battery shell component, thereby opening the opening.

[0054] It should be noted here that:

[0055] If the battery cell assembly is a commercially available square-shell battery with a through hole, the opening is connected to the through hole on the commercially available square-shell battery.

[0056] The single cell provided by the utility model is mainly used to construct a large-capacity battery, such as the large-capacity battery described in the background technology Chinese patent CN220324596U, and can also be used to construct a large-capacity battery disclosed in Chinese patents CN117477063A, CN117477186A, and CN115275453A.

[0057] Such a large-capacity battery comprises at least a plurality of single cells and at least one shared chamber;

[0058] The shared chamber described here is the shared chamber described in CN220324596U, the hollow component described in CN117477063A, the first hollow component and the second hollow component described in CN117477186A, and the electrolyte shared channel described in CN115275453A.

[0059] When the single cell shell component is the single cell lower cover, the shared chamber can be used as an electrolyte shared chamber. An external electrolyte (which can be understood as the electrolyte in the electrolyte sharing chamber) is used to dissolve part of the structure of the sealing component to form an opening in the lower cover. The electrolytes in the inner cavities of each single cell are connected through the electrolyte sharing chamber, so that the electrolytes of all single cells are in the same system, reducing the differences between the electrolytes of each single cell and improving the consistency between the single cells to a certain extent, thereby improving the cycle life of large-capacity batteries to a certain extent.

[0060] When the single cell shell component is the single cell upper cover plate, the shared chamber can also be used as a gas sharing chamber. An external electrolyte (which can be understood as the electrolyte in the gas sharing chamber) is used to dissolve part of the structure of the sealing component to form an opening in the upper cover plate. The gases in the inner cavities of each single cell are connected through the gas sharing chamber, so that the gas in the entire large-capacity battery cavity is balanced, which improves the cycle life of the large-capacity battery to a certain extent.

[0061] When the single cell shell component is a single cell cylinder, the shared chamber can be used as a gas-liquid shared chamber. The external electrolyte (which can be understood as the electrolyte in the gas-liquid sharing chamber) is used to dissolve part of the structure of the sealing component to form an opening on the side wall of the cylinder. The electrolyte and gas in the inner cavity of each single cell can be connected through the gas-liquid sharing chamber, so that the electrolyte and gas of all single cells are in the same system, reducing the differences between the single cells, improving the consistency between the single cells to a certain extent, and thus improving the cycle life of large-capacity batteries to a certain extent.

[0062] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0063] Example 1

[0064] This embodiment is mainly described by taking the single cell housing component as a single cell lower cover plate as an example.

[0065] like Figure 2 As shown in FIG. 1 , it is a schematic structural diagram of the lower cover plate of the single cell in this embodiment. As can be seen from the figure, the lower cover plate of the single cell in this embodiment comprises a cover plate body 1 and a sealing assembly 2 fixed on the cover plate body 1 .

[0066] like Figure 3As shown, the cover body 1 of this embodiment is a rectangular plate, and its area can be slightly larger than the area of ​​the open end of the cylinder, and it is fixed to the open end of the cylinder by welding; it can also be fixed by setting a first step structure around the cover body 1 by welding, and the step surface of the first step structure can also be used as a positioning surface, which can be used to first position the cover at the open end of the cylinder, and then fix it by welding. The area of ​​the cover body 1 can also be slightly smaller than the area of ​​the open end of the cylinder, and it can be fixed to the open end of the cylinder by embedding welding. In some other embodiments, the cover body 1 and the cylinder are an integral part.

[0067] An opening 11 is provided on the cover body 1 , and the position of the opening 11 should correspond to the shared cavity in the large-capacity battery. Generally, the opening 11 can be placed in the exact center of the cover body 1 .

[0068] The size of the opening 11 needs to meet the following conditions:

[0069] 1. The opening 11 cannot be too large to ensure that the entire cover body 1 has a certain strength, so as to avoid the cover body 1 being scrapped due to poor strength before the sealing component 2 at the opening 11 is opened;

[0070] 2. The opening 11 cannot be too small to ensure that after the sealing assembly 2 at the opening 11 is opened, the electrolyte area of ​​each single battery cavity and the inner cavity of the shared chamber are smoothly connected to ensure a good sharing effect.

[0071] In some other embodiments, two openings 11 may be provided on the cover body 1. Generally, the two openings 11 are arranged along the length direction of the cover body and are symmetrical to each other. When the electrode assembly inside the single cell adopts a winding core formed by winding, there is a large space between the side wall of the single cell shell in the width direction and the winding core. When the through hole is opened close to the edge of the cover body 1 in the width direction, firstly, when the through hole is opened, the internal battery cell structure is not affected. Secondly, after opening the sealing assembly 2 at this part, the electrolyte in the inner cavity of the shared chamber can better enter the inner cavity of the single cell.

[0072] The utility model does not limit the shape of the opening 11. Figure 4 It can be seen that the opening 11 in this embodiment is a circular straight through hole. In other embodiments, the shape of the opening 11 can be adjusted according to actual needs, such as a rectangular hole, an elliptical hole, etc.

[0073] like Figure 5 As shown, the sealing assembly 2 of this embodiment includes a protective cap 21 and a dissolving film layer 22 .

[0074] The structure of the protective cap 21 is as follows: Figure 6 and Figure 7As shown, it includes an annular side wall 211 and a bottom plate 212 fixed to one end of the annular side wall 211 and sealing the open end; its shape is adapted to the shape of the opening 11, and a first annular groove 213 is provided along its circumference on the outer surface of the annular side wall 211. Based on the first annular groove 213, the protective cap 21 can be fixed on the cover body 1. The specific fixing method is as follows Figure 8 As shown, the area of ​​the cover body 1 around the opening 11 is embedded in the first annular groove 213, and the open end of the protection cap 21 is located outside the inner cavity of the single battery housing, and the bottom plate 212 of the protection cap 21 is located inside the inner cavity of the single battery housing.

[0075] In this embodiment, the material of the protective cap 21 is an electrolyte-insoluble material and has a certain strength to prevent the protective cap 21 from being damaged due to the pressure of the electrolyte inside the single cell due to poor strength before the sealing component 2 at the opening 11 is opened, thereby causing the single cell to be scrapped.

[0076] At the same time, the protective cap 21 of this embodiment also needs to have a certain degree of elasticity. On the one hand, it can be easily fixed to the opening of the cover body 1. On the other hand, when the inner cavity of the protective cap 21 is filled with the dissolving film layer 22, the protective cap 21 can be squeezed and deformed, so that its annular side wall 211 fits tightly with the cover body 1, ensuring the sealing performance of the sealing component to the opening.

[0077] Therefore, in this embodiment, the protective cap 21 can generally be made of PP or rubber (such as EPDM rubber) with a certain elasticity.

[0078] As mentioned above, the utility model uses the inner cavity of the protective cap 21 as the dissolving film layer accommodating cavity 215; Fig. 9 , fix the dissolving film layer 22 in the dissolving film layer accommodating cavity 215, expand the dissolving film layer accommodating cavity 215, squeeze the annular side wall 211 of the protective cap 21 to fit tightly with the cover body 1, fix the protective cap 21 on the cover body 1, and seal the opening 11 at the same time.

[0079] In this embodiment, the dissolving film layer 22 is a material soluble in electrolyte. Generally, the block-shaped dissolving film layer 22 can be inserted into the dissolving film layer accommodating cavity 215 to expand the dissolving film layer accommodating cavity 215. The material of the dissolving film layer 22 is at least one of PS, PMMA, SMMA, TPU, ABS, POM, PA6, PA12, and PVC.

[0080] In order to improve the bonding strength between the dissolving film layer 22 and the protective cap 21, as Figure 8 and Fig. 9 As shown, in this embodiment, a second annular groove 214 is provided on the inner surface of the annular side wall 211 of the protection cap 21 along the circumference thereof. The dissolving film layer 22 forms an annular protrusion embedded in the second annular groove 214 at this position.

[0081] like Fig.10 As shown, it is a single cell with the above-mentioned lower cover plate of this embodiment;

[0082] In this embodiment, the sealing assembly 2 can be fixed on the cover plate body 1 by the following process:

[0083] First, fix the protective cap 21 to the opening 11 of the cover body 1 so that the edge of the opening 11 is embedded in the first annular groove 213 of the protective cap 21;

[0084] Secondly, hot melt material is poured into the dissolving film layer accommodating cavity 215 to expand the dissolving film layer accommodating cavity 215, and the annular side wall 211 of the extruded protective cap 21 is tightly fitted with the cover plate body 1 to seal the opening 11; after the hot melt material is cooled, a dissolving film layer 22 is formed.

[0085] The liquid circuit can be opened through the following process:

[0086] After the assembly of the large-capacity battery is completed, the electrolyte is injected into the electrolyte sharing chamber to make the dissolving film layer 22 automatically dissolve from the outside. Since the protective cap 21 has a certain elasticity and is assembled with the cover body 1 in a manner similar to a stopper, when the dissolving film layer 22 dissolves, the protective cap 21 will shrink to its original size and automatically fall off from the cover body 1 (see Fig.11 and Fig.12 ), so that the electrolyte shared chamber is connected with the inner cavity of the single battery, so that the electrolyte of all single batteries is in the same system.

[0087] Example 2

[0088] This embodiment is described by taking the single cell housing component as a single cell upper cover plate as an example.

[0089] like Fig.13 and Fig.14 As shown, the opening 11 of this embodiment is located between the two poles 3. The opening 11 can be a round hole, a square hole or other polygonal hole, which can be selected according to actual needs. In some other embodiments, there can be two openings 11, which are located on both sides of the two poles 3 respectively.

[0090] The size of the opening 11 needs to ensure that the gas in the inner cavity of the single battery housing can escape and allow external electrolyte to enter the inner cavity of the single battery housing through the opening 11.

[0091] The sealing assembly 2 can be fixed on the cover plate body 1 by the same method as in Example 1.

[0092] The gas line can be opened through the following process:

[0093] After the assembly of the large-capacity battery is completed, the electrolyte is injected into the gas sharing chamber to allow the dissolving film layer 22 to automatically dissolve from the outside. Since the protective cap 21 has a certain elasticity and is assembled with the cover body 1 only in a manner similar to a stopper, when the dissolving film layer 22 dissolves, the protective cap 21 will shrink to its original size and automatically fall off from the cover body 1, thereby allowing the gas sharing chamber to communicate with the inner cavity of the single battery, thereby achieving the effect of gas balance in all single batteries.

Claims

1. A sealing assembly, characterized in that: Used to seal the opening on the housing member of the single cell, including a protective cap and a dissolving film layer; The protective cap includes an annular side wall and a bottom plate; the annular side wall is used to be fixed to the single cell housing component area around the opening, the bottom plate is located in the inner cavity of the single cell housing, and the cavity of the protective cap serves as a dissolving film layer accommodating cavity; The dissolving film layer is fixed in the dissolving film layer containing cavity, so that the dissolving film layer containing cavity is expanded, and the annular side wall of the extruded protective cap is fitted with the single cell housing component area around the opening, thereby sealing the opening; The material of the protective cap is an elastic material that is insoluble in electrolyte, and the material of the dissolving film layer is an electrolyte soluble material.

2. The sealing assembly according to claim 1, characterized in that: A first annular groove is formed on the outer surface of the annular side wall of the protection cap along the circumference thereof.

3. The sealing assembly according to claim 1 or 2, characterized in that: A second annular groove is provided on the inner surface of the annular side wall of the protective cap along its circumference; and the dissolving film layer is provided with an annular protrusion embedded in the second annular groove.

4. The sealing assembly according to claim 1, characterized in that: The material of the dissolving film layer is PS, PMMA, SMMA, TPU, ABS, POM, PA6, PA12 or PVC.

5. The sealing assembly according to claim 1, characterized in that: The material of the protective cap is PP or EPDM rubber.

6. A single cell battery housing component, characterized in that: An opening penetrating the inner cavity of the single cell housing is provided on the single cell housing component, and a sealing assembly according to any one of claims 1 to 5 is fixed to the single cell housing component region around the opening.

7. A single cell battery, characterized in that: The invention comprises the single cell casing member as claimed in claim 6.

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