Laminated cell and lithium battery

Abstract

The utility model discloses a laminated battery cell, which comprises a battery cell main body and a tab group, the battery cell main body is formed by laminating a plurality of pole pieces, the edge of each pole piece is provided with a notch, a plurality of notches are laminated to form an avoiding groove, and the two side parts of the avoiding groove are configured as expansion areas; and the tab group is connected with the battery cell main body and comprises a bent part which is accommodated in the avoiding groove. The utility model further discloses a lithium battery which comprises the laminated battery cell. According to the technical scheme of the utility model, one edge of the battery cell main body is provided with the avoiding groove, and the avoiding groove is used for accommodating the bending part of the tab group, so that the packaging space occupied by the tab group is reduced, and a larger space is reserved for the expansion of a pole piece. And meanwhile, the two side parts of the avoiding groove are configured to be expansion areas, so that the area of the pole piece coated with the active substance is enlarged, and the energy density of the laminated battery cell is further improved.

Description

Technical Field

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

[0002] The laminated cell is a commonly used lithium-ion battery structure, which is composed of multiple layers of positive and negative electrodes and separators. The lamination process of the laminated cell mainly includes two types: single-pole lamination and multi-pole lamination. Among them, multi-pole lamination means that each cell has multiple positive ears and multiple negative ears. Multiple positive ears or multiple negative ears are welded on the same conductive sheet, and then the conductive sheet is connected to the external circuit. The advantage of multi-pole lamination is that the internal resistance of the cell is low and the conductivity is good, which is suitable for high-power and large-capacity applications.

[0003] The volume of the battery cell has a great influence on the volume energy density of the battery cell. The volume energy density refers to the energy stored per unit volume of the battery cell. The higher the energy density, the longer the battery life. The energy density of the battery cell mainly depends on the area of ​​the pole piece and the content of active material. The larger the area of ​​the pole piece, the more active material is coated on the pole piece, and the greater the energy density.

[0004] At present, in order to save battery cell packaging space and improve the energy density of the battery cell, in the multi-electrode tab stacking process, multiple tabs are usually bent and brought closer to the battery cell body before packaging. However, the bent tab method still occupies part of the packaging space, limiting the expansion of the pole sheet area, thereby affecting the overall energy density of the battery cell. Utility Model Content

[0005] The main purpose of the utility model is to provide a laminated battery core, which can increase the area of ​​the pole piece, thereby improving the energy density of the battery core.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0007] A laminated battery cell, comprising:

[0008] The battery cell body is formed by a plurality of electrode sheets, each electrode sheet has a notch at its edge, and a plurality of notches are stacked to form an avoidance groove, and both sides of the avoidance groove are configured as expansion areas;

[0009] The tab group is connected to the battery body, and the tab group includes a bending portion, and the bending portion is accommodated in the avoidance groove.

[0010] In some embodiments, the tab group is provided with an adhesive sheet, and the adhesive sheet protrudes from the edge of the tab group.

[0011] In some embodiments, the distance from the adhesive sheet to the bottom of the avoidance groove is greater than the depth of the avoidance groove.

[0012] In some embodiments, the notch of the avoidance groove is arranged in a flared shape; and / or, the angle formed by the bottom edge and the side edge of the avoidance groove is 110°-160°.

[0013] In some embodiments, the tab group includes a plurality of stacked tab sheets, and each of the tab sheets is connected to a corresponding pole sheet.

[0014] In some embodiments, the pole tab and the pole piece are an integrally formed structure, or the pole tab is welded to the pole piece.

[0015] In some embodiments, the tab group further includes a conductive sheet connected to the plurality of tab sheets.

[0016] In some embodiments, the conductive sheet is welded to the plurality of tab sheets.

[0017] In some embodiments, the electrode tab group includes a positive electrode tab group and a negative electrode tab group, and the positive electrode tab group and the negative electrode tab group are spaced apart and distributed at the bottom of the avoidance groove.

[0018] The embodiment of the utility model further provides a lithium battery, which includes the laminated battery core as described in the above embodiment.

[0019] In the technical solution of the utility model, an edge of the battery body is configured with a relief groove, which is used to accommodate the bent portion of the tab group, thereby reducing the packaging space occupied by the tab group and reserving more space for the expansion of the pole piece. At the same time, the two sides of the relief groove are configured as expansion areas, thereby increasing the area where the pole piece is coated with active materials, thereby improving the energy density of the laminated battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of a laminated battery cell in the prior art;

[0021] Figure 2 This is a schematic diagram of the structure of a laminated battery cell in one embodiment of the utility model;

[0022] Figure 3 for Figure 2 The enlarged view of point A in the middle;

[0023] Figure 4 for Figure 2 Cross-sectional view at BB in the middle.

[0024] Description of Figure Numbers

[0025] Label name Label name 1 Battery body 11 Pole piece 100 Avoid groove 2 Tab Group 3 Adhesive sheet 21 Tab 22 Conductive sheet 211 Bending part 20 Tab 200 Expanded area

[0026] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] In the present invention, the terms "disposed", "provided with", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in this utility model can be understood according to specific circumstances.

[0031] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0032] Laminated cells are a commonly used lithium-ion battery structure, which consists of multiple positive and negative electrodes and separators. Laminated cells are widely used in soft-pack batteries and square batteries because of their high energy density, stable internal structure and high safety.

[0033] In the prior art, such as Figure 1 As shown, in order to save the packaging space of the laminated battery cell and improve the energy density of the laminated battery cell, in the process of manufacturing the laminated battery cell, a plurality of tabs 20 are usually bent and brought close to the battery cell body 1 before packaging. Although the space occupied by the bent tabs 20 is reduced to a certain extent, the bent tabs 20 still occupy part of the packaging space, limiting the expansion of the pole sheet area, thereby affecting the energy density of the overall battery cell. At the same time, since there is no structural support on both sides of the tabs 20, after packaging with aluminum-plastic film, the edge of the battery cell body 1 close to the tabs 20 is prone to soft collapse, and the packaging stability is poor.

[0034] In this regard, the present invention provides a laminated battery cell, which can increase the electrode area and thus improve the energy density of the battery cell. Figure 2 , Figure 3 and Figure 4 , Figure 2 This is a schematic diagram of the structure of the laminated battery cell in this embodiment; Figure 3 for Figure 2 The enlarged view of point A in the middle; Figure 4 for Figure 2 Cross-sectional view at BB in the middle.

[0035] The laminated battery cell of the present embodiment includes a battery cell body 1 and a pole tab group 2. The battery cell body 1 is formed by stacking a plurality of pole pieces 11. The edge of each pole piece 11 is configured with a notch. The plurality of notches are stacked to form an avoidance groove 100. Both sides of the avoidance groove 100 are configured as expansion areas 200. The pole tab group 2 is connected to the battery cell body 1. The pole tab group 2 includes a bending portion 211, and the bending portion 211 is accommodated in the avoidance groove 100.

[0036] In this embodiment, the battery cell body 1 includes a plurality of electrode sheets 11 and a separator, the electrode sheets 11 include a positive electrode sheet and a negative electrode sheet, and the electrode sheets 11 are metal foil sheets, for example, the positive electrode sheet may be an aluminum foil sheet, and the negative electrode sheet may be a copper foil sheet. A plurality of positive electrode sheets, separators, and negative electrode sheets are stacked in sequence to form the battery cell body 1.

[0037] Since the energy density of the battery cell mainly depends on the content of the active material on the pole piece 11, the area of ​​the pole piece 11 has a great influence on the energy density of the battery cell. The larger the area of ​​the pole piece 11, the more active material is coated on the pole piece 11, and the greater the energy density. Therefore, in order to increase the area of ​​the pole piece 11, the pole tab group 2 of this embodiment includes a bending portion 211, shortens the length of the pole tab group 2, and reduces the packaging space occupied by the pole tab group 2, so as to ensure that more space can be reserved for the pole piece 11 when the volume of the battery cell is certain.

[0038] In order to further reduce the packaging space occupied by the tab group 2, a side edge of the battery body 1 of the present embodiment is constructed with an avoidance groove 100, and the avoidance groove 100 is used to accommodate the bent portion 211 of the tab group 2. Specifically, an edge of each pole piece 11 is cut out with an inwardly recessed notch, and a plurality of notches are stacked to form the avoidance groove 100. In the present embodiment, since the bent portion of the tab group 2 is accommodated in the avoidance groove 100 of the battery body 1, the packaging space occupied by the tab group 2 is further reduced, and more space is reserved for the expansion of the pole piece 11. At the same time, the two sides of the avoidance groove 100 are configured as the expansion area 200 of the pole piece 11. Compared with the pole piece with four straight sides in the prior art, the pole piece 11 of the present embodiment adds the expansion area 200 to coat more active materials, thereby improving the energy density of the laminated battery cell. At the same time, since the pole piece 11 of this embodiment adds the expanded area 200 on both sides of the avoidance groove 100, the pole piece 11 is supported on both sides of the pole lug group 2. After being packaged with aluminum-plastic film, the overall thickness of the laminated battery cell is more uniform, thereby improving the packaging stability of the battery cell.

[0039] In some embodiments, Figure 3 As shown, the tab group 2 is provided with an adhesive sheet 3 , and the adhesive sheet 3 protrudes from the edge of the tab group 2 .

[0040] In this embodiment, the adhesive sheet 3 is applied to the packaging process of the laminated battery. Specifically, the laminated battery also includes a packaging film, which covers the battery body 1. The adhesive sheet 3 of this embodiment is arranged on the tab group 2 and protrudes from the edge of the tab group 2 to increase the contact area between the adhesive sheet 3 and the packaging film and improve the stability of the packaging. Optionally, the adhesive sheet 3 of this embodiment is a hot melt adhesive, and the tab group 2 is bonded to the packaging film by hot melting.

[0041] In some embodiments, Figure 3 As shown, the distance h1 from the adhesive sheet 3 to the bottom of the avoidance groove 100 is greater than the groove depth h2 of the avoidance groove 100 .

[0042] In the present embodiment, since the adhesive sheet 3 protrudes out of the edge of the tab group 2, in order to avoid interference between the adhesive sheet 3 and the groove wall of the avoidance groove 100, the distance h1 from the adhesive sheet 3 to the bottom of the avoidance groove 100 of the present embodiment is slightly larger than the groove depth h2 of the avoidance groove 100, so that the compactness of the package can be maintained as much as possible without interfering with the groove wall of the avoidance groove 100.

[0043] In some embodiments, the notch of the avoidance groove 100 is arranged in a flared shape; and / or, the angle formed by the bottom edge and the side edge of the avoidance groove 100 is 110°-160°.

[0044] In this embodiment, the groove walls of the avoidance groove 100 are inclined, specifically, the groove walls of the two sides are inclined outwards and are flared, so as to further expand the avoidance space of the battery body 1 and avoid interference between the adhesive sheet 3 and the groove wall of the avoidance groove 100.

[0045] Taking into account the area of ​​the expansion region 200 and the mechanical properties at the expansion region 200, the angle formed by the bottom edge and the side edge of the avoidance groove 100 in this embodiment is set to 110°-160°. In this way, the area of ​​the expansion region 200 is guaranteed to a large extent to improve the energy density of the battery cell, and the strength of the pole piece 11 at the expansion region 200 is guaranteed to avoid the pole piece from breaking.

[0046] In some embodiments, Figure 4 As shown, the pole tab group 2 includes a plurality of pole tab sheets 21 arranged in layers, and each pole tab sheet 21 is connected to a corresponding pole sheet 11 .

[0047] The tab group 2 in this embodiment includes a plurality of tab sheets 21, which may be metal foils, such as aluminum foil, copper foil, etc. The plurality of tab sheets 21 are stacked, and each tab sheet 21 is connected to a pole sheet 11. The plurality of tab sheets 21 are stacked and bent to form a bent portion 211 of the tab group 2.

[0048] In some embodiments, the pole tab 21 and the pole piece 11 are an integrally formed structure, or the pole tab 21 is welded to the pole piece 11 .

[0049] In this embodiment, the connection method between the pole piece 21 and the pole piece 11 can be an integrally formed structure. For example, the pole piece 21 can be formed by cutting the pole piece 11. The connection method between the pole piece 21 and the pole piece 11 can also be welding, such as ultrasonic welding.

[0050] In some embodiments, the tab group 2 further includes a conductive sheet 22 , and the conductive sheet 22 is connected to the plurality of tab sheets 21 .

[0051] The conductive sheet 22 of this embodiment is used to connect the multiple pole tabs 21 to achieve conduction between the laminated battery cell and an external electrical device. Specifically, after the multiple pole tabs 21 are stacked and bent, the conductive sheet 22 is connected to the end of the pole sheet 11 away from the battery cell body 1, and is electrically connected to the multiple pole tabs 21. Exemplarily, the conductive sheet 22 is welded to the multiple pole tabs 21, and the welding method can be ultrasonic welding.

[0052] In some embodiments, the electrode tab group 2 includes a positive electrode tab group and a negative electrode tab group, and the positive electrode tab group and the negative electrode tab group are spaced apart and distributed at the bottom of the avoidance groove 100 .

[0053] The tab group 2 of this embodiment includes a positive tab group and a negative tab group. The positive tab group includes a plurality of stacked positive tab sheets, which may be aluminum foil sheets, and each positive tab sheet is connected to a positive tab sheet. The negative tab group includes a plurality of stacked negative tab sheets, which may be copper foil sheets, and each negative tab sheet is connected to a negative tab sheet. The positive tab group and the negative tab group are spaced apart, and the bending portions 211 of both are accommodated in the limiting groove.

[0054] The utility model also provides a lithium battery in an embodiment. The lithium battery includes the laminated battery core as described in the above embodiment.

[0055] The specific structure of the laminated battery core refers to the above embodiments. Since the lithium battery adopts all the technical solutions of all the above embodiments, it at least has all the technical effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0056] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A laminated battery cell, characterized in that: include The battery cell body is formed by a plurality of electrode sheets, each electrode sheet has a notch at its edge, and a plurality of notches are stacked to form an avoidance groove, and both sides of the avoidance groove are configured as expansion areas; The tab group is connected to the battery body, and the tab group includes a bending portion, and the bending portion is accommodated in the avoidance groove.

2. The laminated battery cell according to claim 1, characterized in that: The tab group is provided with an adhesive sheet, and the adhesive sheet protrudes from the edge of the tab group.

3. The laminated battery cell according to claim 2, characterized in that: The distance from the adhesive sheet to the bottom of the avoidance groove is greater than the groove depth of the avoidance groove.

4. The laminated battery cell according to claim 2, characterized in that: The notch of the avoidance groove is arranged in a flared shape; and / or the angle formed by the bottom edge and the side edge of the avoidance groove is 110°-160°.

5. The laminated battery cell according to claim 1, characterized in that: The pole tab group includes a plurality of pole tab sheets stacked together, and each of the pole tab sheets is connected to a corresponding pole sheet.

6. The laminated battery cell according to claim 5, characterized in that: The pole tab and the pole piece are an integrally formed structure, or the pole tab is welded to the pole piece.

7. The laminated battery cell according to claim 5, characterized in that: The tab group further includes a conductive sheet connected to the plurality of tab sheets.

8. The laminated battery cell according to claim 7, characterized in that: The conductive sheet is welded to the plurality of tab sheets.

9. The laminated battery cell according to claim 1, characterized in that: The electrode tab group includes a positive electrode tab group and a negative electrode tab group, and the positive electrode tab group and the negative electrode tab group are spaced apart and distributed at the bottom of the avoidance groove.

10. A lithium battery, characterized in that: It comprises a laminated battery core as described in any one of claims 1 to 9.

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