Laminated cell structure and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a laminated cell structure and a battery. The laminated battery cell structure is formed by a composite pole piece belt through Z-shaped lamination, the composite pole piece belt comprises a first pole piece, a second pole piece, diaphragm belts and a connecting adhesive layer, and the two diaphragm belts are arranged in parallel at an interval; the plurality of first pole pieces are arranged between the two diaphragm belts at intervals along the length direction of the diaphragm belts; the polarity of the second pole pieces is opposite to that of the first pole pieces, and the multiple second pole pieces are sequentially arranged on the sides, deviating from the first pole pieces, of the two diaphragm belts in a staggered mode and directly face one first pole piece; the first pole piece and the second pole piece are connected with the corresponding diaphragm belts through connecting glue layers, each connecting glue layer comprises a first connecting layer and a second connecting layer which are sequentially arranged in the thickness direction of the diaphragm belts, and at least one of the first connecting layer and the second connecting layer is a PVDF glue layer. The laminated battery cell structure can avoid dislocation of the positive plate and the negative plate in the lamination process, and is relatively high in safety and stability.

Description

Technical Field

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

[0002] With the rapid development of science and technology, lithium-ion batteries, as an efficient and environmentally friendly energy storage device, have been widely used in the fields of mobile communication, electric vehicles, energy storage systems, etc. Among them, square lithium-ion batteries have become one of the mainstream products in the market due to their compact structure, large capacity, high safety, etc.

[0003] The manufacturing processes of battery cells in square lithium-ion batteries usually include winding and laminating. Compared with the winding process, the laminating process is superior in terms of energy density, cycle life, and safety. Among them, the laminating process usually includes the following three methods: 1) Thermal composite lamination. After cutting the positive electrode sheet, separator, and negative electrode sheet, they are thermally combined to form independent units, and then several such units are overlapped to form an electrode core. This lamination method has low production efficiency, and since the separator is cut into small-sized sheets, there is no binding force on both sides of the separator, and when the battery cell is heated, the separator is prone to shrinkage, which may cause the positive electrode sheet and the negative electrode sheet to contact and cause a short circuit; 2) Bag-making lamination. The positive electrode sheet is wrapped with a separator, and then the four sides of the separator are heat-sealed, and then laminated alternately with the negative electrode sheet. In this lamination method, the separator is prone to rupture during the heat-sealing operation, and the position of the positive electrode sheet in the bag-type separator is not fixed, and it is easy to deviate and misalign, affecting the quality of the finished product; 3) Z-type lamination. During the Z-shaped reciprocating process of the separator, the positive and negative electrode sheets are cross-inserted. In this lamination method, the impedance of the battery cell is small, but the electrode sheets are prone to misalignment and cause a short circuit, and the safety is poor.

[0004] Therefore, it is urgent to propose a laminated battery cell structure to solve the above problems. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a laminated battery cell structure and a battery, which can avoid the misalignment of the positive and negative electrode sheets during the lamination process, and can improve the stability and safety of the laminated battery cell structure.

[0006] Based on the above concept, the technical solution adopted by the utility model is as follows:

[0007] A laminated battery cell structure is formed by Z-type lamination of a composite electrode strip, and the composite electrode strip includes:

[0008] Separator strips, two of the separator strips are arranged in parallel and at intervals;

[0009] First electrode sheets, a plurality of the first electrode sheets are arranged at intervals between the two separator strips along the length direction of the separator strips;

[0010] The second pole piece, which has a polarity opposite to that of the first pole piece, and a plurality of the second pole pieces are sequentially arranged in an interleaved manner on one side of each of the two separator tapes facing away from the first pole piece, and all face one first pole piece;

[0011] A connecting adhesive layer, both the first pole piece and the second pole piece are connected to the corresponding separator tape through the connecting adhesive layer, the connecting adhesive layer includes a first connecting layer and a second connecting layer sequentially arranged along the thickness direction of the separator tape, and at least one of the first connecting layer and the second connecting layer is a PVDF adhesive layer.

[0012] As a preferred solution of the stacked battery cell structure provided by the present invention, the first connecting layer is a ceramic layer, the second connecting layer is a PVDF adhesive layer, and the first connecting layer is arranged close to the separator tape.

[0013] As a preferred solution of the stacked battery cell structure provided by the present invention, the coating amount of the first connecting layer on each separator tape is 0.1 g / m 2 ~10 g / m 2 。

[0014] As a preferred solution of the stacked battery cell structure provided by the present invention, the coating amount of the second connecting layer on each separator tape is 0.1 g / m 2 ~2 g / m 2 。

[0015] As a preferred solution of the stacked battery cell structure provided by the present invention, the number of the connecting adhesive layers is multiple, and the multiple connecting adhesive layers are sequentially stacked along the thickness direction of the separator tape.

[0016] As a preferred solution of the stacked battery cell structure provided by the present invention, both the first connecting layer and the second connecting layer are PVDF adhesive layers.

[0017] As a preferred solution of the stacked battery cell structure provided by the present invention, the first pole piece is a negative electrode piece, and the second pole piece is a positive electrode piece.

[0018] As a preferred solution of the stacked battery cell structure provided by the present invention, the length of the negative electrode piece is greater than the length of the positive electrode piece; and / or the width of the negative electrode piece is greater than the width of the positive electrode piece.

[0019] As a preferred solution of the stacked battery cell structure provided by the present invention, the length L1 of the negative electrode piece is greater than the length L2 of the positive electrode piece; and / or the width M1 of the negative electrode piece is greater than the width M2 of the positive electrode piece.

[0020] The present utility model also provides a battery, which includes a housing and the laminated cell structure as described above, and the laminated cell structure is disposed within the housing.

[0021] The beneficial effects of the present utility model are as follows:

[0022] The present utility model provides a laminated cell structure. By forming the composite pole piece tape in a Z-shaped lamination, the internal structure of the battery can be made more compact, with a higher energy density, better internal structure stability, higher safety, and a longer cycle life. By providing a connecting adhesive layer, both the first pole piece and the second pole piece are connected to the corresponding separator tape through the connecting adhesive layer, and at least one of the first connecting layer and the second connecting layer is a PVDF adhesive layer, which can firmly adhere the first pole piece to the separator tape and the second pole piece to the separator tape, so as to prevent the first pole piece or the second pole piece from being misaligned during the lamination process, thereby improving the stability and safety of the laminated cell structure.

[0023] The present utility model provides a battery. By applying the above-mentioned laminated cell structure, misalignment of the positive and negative pole pieces during the lamination process can be avoided, and both the safety and stability are relatively high. Description of the Drawings

[0024] Figure 1 is a schematic structural view of the laminated cell structure (without showing the connecting adhesive layer) provided by the present utility model;

[0025] Figure 2 is a schematic structural view of the composite pole piece tape provided in Embodiment 1 of the present utility model;

[0026] Figure 3 is a schematic structural view of the composite pole piece tape provided in Embodiment 2 of the present utility model.

[0027] In the figure:

[0028] 100, the first pole piece;

[0029] 200, the second pole piece;

[0030] 300, the separator tape;

[0031] 400, the connecting adhesive layer; 410, the first connecting layer; 420, the second connecting layer. Detailed Embodiments

[0032] The present utility model will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than to limit the present utility model. Additionally, it should be noted that for the sake of description, only the parts related to the present utility model rather than all the structures are shown in the drawings.

[0033] In the description of the present utility model, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0034] In the present utility model, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0035] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "left", and "right" are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0036] Embodiment 1

[0037] Figure 1 The structural schematic diagram of the stacked battery cell structure (the connection adhesive layer 400 is not shown) provided by this embodiment is shown. Figure 2 The structural schematic diagram of the composite pole piece tape provided by this embodiment is shown. As Figure 1 - Figure 2 shown, this embodiment provides a stacked battery cell structure, and this stacked battery cell structure is composed of Figure 2The shown composite pole piece tape is formed by Z-shaped lamination. The composite pole piece tape includes a first pole piece 100, a second pole piece 200, a separator tape 300, and a connecting adhesive layer 400. Among them, two separator tapes 300 are arranged in parallel and at intervals; a plurality of first pole pieces 100 are arranged at intervals between the two separator tapes 300 along the length direction of the separator tape 300; the second pole piece 200 has the opposite polarity to the first pole piece 100, and a plurality of second pole pieces 200 are arranged in a staggered manner in turn on the sides of the two separator tapes 300 facing away from the first pole piece 100 respectively, and all are opposite to one first pole piece 100; both the first pole piece 100 and the second pole piece 200 are connected to the corresponding separator tape 300 through the connecting adhesive layer 400. The connecting adhesive layer 400 includes a first connecting layer 410 and a second connecting layer 420 arranged in sequence along the thickness direction of the separator tape 300, and at least one of the first connecting layer 410 and the second connecting layer 420 is a PVDF (polyvinylidene fluoride) adhesive layer.

[0038] It should be noted that Figure 1 the cross-hatching marked on the first pole piece 100 and the second pole piece 200 only indicates that the two are two pole pieces with opposite polarities.

[0039] For the laminated battery cell structure provided in this embodiment, by forming the composite pole piece tape by Z-shaped lamination, the internal structure of the battery can be made more compact, the energy density can be higher, the internal structure stability can be better, the safety can be higher, and the cycle life can be longer; by setting the connecting adhesive layer 400, both the first pole piece 100 and the second pole piece 200 are connected to the corresponding separator tape 300 through the connecting adhesive layer 400, and at least one of the first connecting layer 410 and the second connecting layer 420 is a PVDF adhesive layer, which can firmly adhere the first pole piece 100 to the separator tape 300 and the second pole piece 200 to the separator tape 300 together to prevent the first pole piece 100 or the second pole piece 200 from being misaligned during the lamination process, thereby improving the stability and safety of the laminated battery cell structure.

[0040] As Figure 2 shown, in this embodiment, both the first connecting layer 410 and the second connecting layer 420 are PVDF adhesive layers, with a simple structure, convenient processing, and can reduce the processing procedures and costs.

[0041] Optionally, the coating amount of the first connecting layer 410 and the second connecting layer 420 on each separator tape 300 is 0.1 g / m 2 ~2 g / m 2 . Exemplarily, the coating amount of the first connecting layer 410 and the second connecting layer 420 on each separator tape 300 can be 0.2 g / m 2 , 0.3 g / m 2 , 0.4 g / m 2 , 0.5 g / m 2 , 0.6 g / m2 , 0.7 g / m 2 , 0.8 g / m 2 , 0.9 g / m 2 , 1.0 g / m 2 , 1.1 g / m 2 , 1.2 g / m 2 , 1.3 g / m 2 , 1.4 g / m 2 , 1.5 g / m 2 , 1.6 g / m 2 , 1.7 g / m 2 , 1.8 g / m 2 , 1.9 g / m 2 etc. It should be noted that the coating amount of the first connection layer 410 on each separator tape 300 may be the same as or different from the coating amount of the second connection layer 420, and this embodiment does not make any limitation in this regard.

[0042] Continue as Figure 1 - Figure 2 shown. The first electrode tab 100 is a negative electrode tab, and the second electrode tab 200 is a positive electrode tab. To ensure the safety of the stacked battery cell structure, in this embodiment, the length of the negative electrode tab is greater than the length of the positive electrode tab; the width of the negative electrode tab is greater than the width of the positive electrode tab. Optionally, the length L1 of the negative electrode tab and the length L2 of the positive electrode tab satisfy: 1.5 mm < L1 - L2 < 3.5 mm; the width M1 of the negative electrode tab and the width M2 of the positive electrode tab satisfy: 1.5 mm < M1 - M2 < 3.5 mm. Exemplarily, the value of L1 - L2 can be 1.6 mm, 1.8 mm, 2.0 mm, 2.5 mm, 2.8 mm, 3.0 mm, 3.2 mm, etc.; the value of M1 - M2 can be 1.6 mm, 1.8 mm, 2.0 mm, 2.5 mm, 2.8 mm, 3.0 mm, 3.2 mm, etc. It should be noted that the value of L1 - L2 and the value of M1 - M2 may be equal or unequal, and this embodiment does not make any limitation in this regard.

[0043] Embodiment 2

[0044] This embodiment provides a stacked battery cell structure. The specific structure of this stacked battery cell structure is substantially the same as the specific structure of the stacked battery cell structure in Embodiment 1, except that: the structure of the connection adhesive layer 400 is different.

[0045] Figure 3 shows a schematic structural diagram of the composite electrode tab strip provided in this embodiment. As Figure 3 and in combination with Figure 1As shown, in this embodiment, the first connection layer 410 is a ceramic layer, the second connection layer 420 is a PVDF adhesive layer, and the first connection layer 410 is disposed close to the separator tape 300. By coating the ceramic layer on the separator tape 300, the heat resistance of the separator tape 300 can be improved, preventing it from shrinking during hot pressing and further ensuring the safety of the laminated battery cell structure.

[0046] Optionally, the coating amount of the first connection layer 410 on each separator tape 300 is 0.1 g / m 2 ~10 g / m 2 . Exemplarily, the coating amount of the first connection layer 410 on each separator tape 300 can be 0.2 g / m 2 、0.5 g / m 2 、0.8 g / m 2 、1.0 g / m 2 、1.2 g / m 2 、1.5 g / m 2 、1.8 g / m 2 、2.0 g / m 2 、2.2 g / m 2 、2.5 g / m 2 、3.0 g / m 2 、3.2 g / m 2 、3.5 g / m 2 、3.8 g / m 2 、4.0 g / m 2 、4.2 g / m 2 、4.5 g / m 2 、4.8 g / m 2 、5.0 g / m 2 、5.2 g / m 2 、5.5 g / m 2 、6.0 g / m 2 、6.2 g / m 2 、6.5 g / m 2 、6.8 g / m 2 、7.0 g / m 2 、7.2 g / m 2 、7.5 g / m 2 、7.8 g / m 2 、8.0 g / m 2 、8.2 g / m 2 、8.5 g / m 2 、9.0 g / m 2 、9.2 g / m 2 、9.5 g / m 2 、9.8 g / m 2 etc.

[0047] Optionally, the coating amount of the second connection layer 420 on each separator tape 300 is 0.1 g / m 2 ~2 g / m 2 Exemplarily, the coating amount of the second connection layer 420 on each separator tape 300 can be 0.2 g / m 2 、0.3 g / m 2 、0.4 g / m 2 、0.5 g / m 2 、0.6 g / m 2 、0.7 g / m 2 、0.8 g / m 2 、0.9 g / m 2 、1.0 g / m 2 、1.1 g / m 2 、1.2 g / m 2 、1.3 g / m 2 、1.4 g / m 2 、1.5 g / m 2 、1.6 g / m 2 、1.7 g / m 2 、1.8 g / m 2 、1.9 g / m 2 etc.

[0048] It should be noted that the coating amount of the first connection layer 410 on each separator tape 300 and the coating amount of the second connection layer 420 can be the same or different, and this embodiment does not limit this.

[0049] Optionally, the number of the connection adhesive layers 400 is multiple, and the multiple connection adhesive layers 400 are sequentially stacked along the thickness direction of the separator tape 300 to further improve the stability of the adhesion between the first electrode sheet 100 and the separator tape 300 and between the second electrode sheet 200 and the separator tape 300. In this embodiment, the number of the connection adhesive layers 400 is one layer. On the premise of ensuring the stable adhesion between the first electrode sheet 100 and the separator tape 300 and between the second electrode sheet 200 and the separator tape 300, the number of the connection adhesive layers 400 is reduced to reduce the processing procedures and lower the processing cost. Of course, in other embodiments, the number of the connection adhesive layers 400 can also be two layers, three layers, four layers, five layers, or even more layers, and this embodiment does not limit this.

[0050] Embodiment III

[0051] This embodiment provides a battery, which includes a housing and a stacked cell structure disposed within the housing. Among them, the stacked cell structure can adopt the stacked cell structure in Embodiment 1 or Embodiment 2. Since the stacked cell structure is formed by Z-shaped stacking of the composite pole piece tape, the battery has the following advantages: 1) The internal structure of the battery is compact, reducing the ineffective space and improving the energy density. Under the same volume and weight, the battery can store more energy; 2) Compared with the winding process, the Z-shaped stacking process can make the contact between the positive electrode sheet, the negative electrode sheet and the separator more uniform, reducing the internal stress concentration and deformation, thereby improving the stability of the internal structure of the battery; 3) The internal resistance of the battery is lower, the expansion force is more stable, the attenuation speed of the battery is slower, and the cycle life of the battery can be extended; 4) It has good thermal stability and mechanical stability, which can reduce the safety risk of the battery under extreme conditions. In addition, the first pole piece 100 and the second pole piece 200 are both connected to the corresponding separator tape 300 through the connecting adhesive layer 400, which can ensure the stability of their connection, avoid misalignment during the stacking process, and further improve the stability and safety of the battery.

[0052] The above embodiments only illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, there are various changes and modifications to the present invention, and these changes and modifications all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laminated battery core structure, formed by Z-shaped lamination of composite electrode strips, characterized in that: The composite pole piece strip comprises: A diaphragm belt (300), wherein two diaphragm belts (300) are arranged in parallel and at intervals; A first pole piece (100), wherein a plurality of the first pole pieces (100) are arranged between two of the diaphragm strips (300) at intervals along the length direction of the diaphragm strip (300); A second pole piece (200) having a polarity opposite to that of the first pole piece (100), a plurality of the second pole pieces (200) being alternately arranged in sequence on a side of the two diaphragm strips (300) respectively facing away from the first pole piece (100), and each of the second pole pieces (200) is directly opposite to one of the first pole pieces (100); A connecting adhesive layer (400), wherein the first pole piece (100) and the second pole piece (200) are both connected to the corresponding diaphragm tape (300) through the connecting adhesive layer (400), and the connecting adhesive layer (400) includes a first connecting layer (410) and a second connecting layer (420) sequentially arranged along the thickness direction of the diaphragm tape (300), and at least one of the first connecting layer (410) and the second connecting layer (420) is a PVDF adhesive layer.

2. The laminated battery core structure according to claim 1, characterized in that: The first connecting layer (410) is a ceramic layer, the second connecting layer (420) is a PVDF adhesive layer, and the first connecting layer (410) is arranged close to the diaphragm belt (300).

3. The laminated battery core structure according to claim 2, characterized in that: The coating amount of the first connecting layer (410) on each of the diaphragm tapes (300) is 0.1 g / m 2 ~10g / m 2 .

4. The laminated battery core structure according to claim 2, characterized in that: The coating amount of the second connecting layer (420) on each of the diaphragm tapes (300) is 0.1 g / m 2 ~2g / m 2 .

5. The laminated battery core structure according to claim 2, characterized in that: The number of the connecting adhesive layers (400) is plural, and the plural connecting adhesive layers (400) are stacked in sequence along the thickness direction of the diaphragm belt (300).

6. The laminated battery core structure according to claim 1, characterized in that: The first connecting layer (410) and the second connecting layer (420) are both PVDF adhesive layers.

7. The laminated battery core structure according to any one of claims 1 to 6, characterized in that: The first pole piece (100) is a negative pole piece, and the second pole piece (200) is a positive pole piece.

8. The laminated battery core structure according to claim 7, characterized in that: The length of the negative electrode sheet is greater than the length of the positive electrode sheet; and / or the width of the negative electrode sheet is greater than the width of the positive electrode sheet.

9. The laminated battery core structure according to claim 8, characterized in that: The length L1 of the negative electrode sheet is greater than the length L2 of the positive electrode sheet; and / or the width M1 of the negative electrode sheet is greater than the width M2 of the positive electrode sheet.

10. A battery, characterized in that: The invention comprises a shell and a laminated battery core structure as claimed in any one of claims 1 to 9, wherein the laminated battery core structure is arranged in the shell.

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