Internal-string battery cell and internal-string battery

Abstract

The utility model discloses an internal series battery cell and an internal series battery, and relates to the technical field of series batteries. The inner-string battery cell comprises N bare battery cells and N-1 partition plates, and N is greater than or equal to 2; the naked battery cells and the partition plates are sequentially and alternately stacked, the adjacent naked battery cells and partition plates are connected through adhesive layers, and the two adjacent adhesive layers are distributed in a staggered manner. According to the inner-string battery cell, the adhesive layers are arranged between the adjacent naked battery cells and the partition plates for connection, so that the two adjacent naked battery cells are relatively fixed, the naked battery cells are prevented from sliding, the qualification rate of the packaged inner-string battery cell can be improved, and the falling performance can also be improved; meanwhile, the two adjacent adhesive layers are distributed in a staggered manner, and the thickness of only one adhesive layer needs to be calculated in thickness calculation, so that the thickness of the inner-string battery cell is reduced, the energy density is improved, the thickness difference of the inner-string battery cell is reduced, and the flatness is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of series-connected battery cells, and in particular to an inner-series battery cell and an inner-series battery. Background Art

[0002] Existing chemical power sources, due to inherent chemical system limitations, often have difficulty breaking through the 5V voltage limit. However, many electrical devices require higher voltage support in practical applications, so connecting batteries in series has become an effective way to increase voltage.

[0003] At present, there are two main forms of bare battery cell series connection: external series battery and internal series battery. External series battery is realized by welding multiple batteries together. Although this method is simple and easy, multiple welding is prone to cause poor welding problems. At the same time, multiple batteries in series may also lead to mismatched electrical properties, thus affecting the overall performance of the battery.

[0004] Relatively speaking, the internal series battery performs better in reducing the number of welding times and improving battery consistency. However, in the internal series battery, the fixation of adjacent bare cells is crucial to prevent the bare cells from moving in the aluminum-plastic film. The commonly used fixation method at present is to stick a glue layer on the deep pit surface of the bare cell, and stick the bare cell to the aluminum-plastic film through the glue layer to achieve fixation, but the effect is not ideal. There is still a possibility of movement between the bare cells, which undoubtedly poses a potential threat to the safety performance of the battery. Utility Model Content

[0005] In view of the deficiencies of the prior art, the utility model provides an inner series cell and an inner series battery.

[0006] The utility model discloses an inner series battery cell, comprising a bare battery cell and a partition, wherein the number of the bare battery cells is N, and the number of the partitions is N-1, wherein N≥2; the bare battery cells and the partitions are alternately stacked in sequence, adjacent bare battery cells and partitions are connected by an adhesive layer, and two adjacent adhesive layers are staggered.

[0007] According to one embodiment of the present invention, the adhesive layer is rectangular.

[0008] According to one embodiment of the present invention, the glue layer is arranged along the length direction of the bare battery core.

[0009] According to one embodiment of the present invention, the positional relationship between two adjacent adhesive layers satisfies the following relationship: D1+W2<D2, wherein D1 is the distance between one of the two adjacent adhesive layers and the first side edge of the bare battery cell along the width direction, D2 is the distance between the other of the two adjacent adhesive layers and the first side edge of the bare battery cell along the width direction, and W2 is the width of the adhesive layer.

[0010] According to an embodiment of the present invention, the length of the glue layer satisfies the following relationship: 0.2L1<L2<L1, wherein L1 is the length of the bare battery cell, and L2 is the length of the glue layer.

[0011] According to one embodiment of the present invention, the width of the glue layer satisfies the following relationship: 0.1W1<W2<0.5W1, wherein W1 is the width of the bare cell, and W2 is the width of the glue layer.

[0012] According to one embodiment of the present invention, the bonding area of ​​the adhesive layer satisfies the following relationship: S2 / S1≥0.1, wherein S1 is the area of ​​the bonded surface of the bare battery cell, and S2 is the area of ​​the bonding surface of the adhesive layer.

[0013] According to an embodiment of the present invention, the thickness of the adhesive layer is 20 to 120 μm.

[0014] According to one embodiment of the utility model, the number of adhesive layers disposed between adjacent bare battery cells and separators is one layer.

[0015] The utility model discloses an inner-series battery, comprising the inner-series battery core as mentioned above, wherein the inner-series battery core is packaged in an outer shell.

[0016] Compared with the prior art, the internal series battery and the internal series battery of the utility model have the following advantages:

[0017] The inner series battery cell of the utility model is connected by setting a glue layer between adjacent bare battery cells and the partition, so as to relatively fix the two adjacent bare battery cells and prevent sliding between the bare battery cells, which can not only improve the qualified rate of the packaged inner series battery cells, but also improve the drop performance; at the same time, the two adjacent glue layers are staggered, and only the thickness of one glue layer needs to be calculated in the thickness calculation, thereby reducing the thickness of the inner series battery cell, improving the energy density, and thus reducing the thickness difference of the inner series battery cell and improving the flatness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0019] Figure 1 This is a structural exploded view of the inner series battery cells in Example 1;

[0020] Figure 2 This is a schematic diagram of the structure of the inner series battery cells in Example 1;

[0021] Figure 3 It is a cross-sectional view of the structure of the inner-series battery cells in Example 1.

[0022] Description of reference numerals:

[0023] 1. Bare battery cell; 11. First side; 2. Partition plate; 3. Glue layer. DETAILED DESCRIPTION

[0024] The following will disclose multiple embodiments of the present invention with diagrams. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the diagram, some conventional structures and components will be depicted in a simple schematic manner in the diagram.

[0025] In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present utility model. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0026] Embodiment 1

[0027] The present embodiment provides an inner-series cell for manufacturing an inner-series battery.

[0028] See also Figure 1 and 2 , the inner series battery cell includes a bare battery cell 1 and a partition 2. The number of bare battery cells 1 is N, and the number of partitions 2 is N-1, where N≥2. The bare battery cells 1 and the partitions 2 are stacked alternately in sequence, two adjacent bare battery cells 1 overlap, and the tabs of two adjacent bare battery cells 1 are flipped symmetrically. In this embodiment, the number of bare battery cells 1 is 2, the number of partitions 2 is 1, and the bare battery cell 1, the partition 2, and the bare battery cell 1 are stacked in sequence.

[0029] Review Figures 1 to 3 , the adjacent bare cells 1 and the separators 2 are connected by the adhesive layer 3, and the two adjacent adhesive layers 3 are staggered. Among them, only one adhesive layer 3 is arranged between the adjacent bare cells 1 and the separators 2.

[0030] Furthermore, the adhesive layer 3 is a hot melt adhesive layer 3. The adhesive layer 3 is rectangular, and the adhesive layer 3 is arranged along the length direction of the bare battery cell 1. The positional relationship between two adjacent adhesive layers 3 satisfies the following relationship: D1+W2<D2. Among them, D1 is the distance between one of the two adjacent adhesive layers 3 and the first side 11 of the bare battery cell 1 along the width direction, D2 is the distance between the other of the two adjacent adhesive layers 3 and the first side 11 of the bare battery cell 1 along the width direction, and W2 is the width of the adhesive layer 3.

[0031] Furthermore, the length of the glue layer 3 satisfies the following relationship: 0.2L1<L2<L1, wherein L1 is the length of the bare battery cell 1, and L2 is the length of the glue layer 3.

[0032] Furthermore, the width of the adhesive layer 3 satisfies the following relationship: 0.1W1<W2<0.5W1, wherein W1 is the width of the bare battery cell 1, and W2 is the width of the adhesive layer 3.

[0033] Furthermore, the bonding area of ​​the adhesive layer 3 satisfies the following relationship: S2 / S1≥0.1, wherein S1 is the area of ​​the bonded surface of the bare cell 1, which is obtained by multiplying the length and width of the bare cell 1; S2 is the area of ​​the bonding surface of the adhesive layer 3, which is obtained by multiplying the length and width of the adhesive layer 3.

[0034] Furthermore, the thickness of the adhesive layer 3 is 20-120 μm.

[0035] It should be noted that the above-mentioned length is the side length dimension in the Y-axis direction shown in the figure, the above-mentioned width is the side length dimension in the X-axis direction described in the figure, and the above-mentioned thickness is the side length dimension in the Z-axis direction described in the figure. In addition, in the length direction, one side edge of the bare battery cell 1 is selected as the above-mentioned first side edge 11, and the first side edges 11 of all bare battery cells 1 are on the same side.

[0036] To summarize, the inner series battery cells are connected by setting a glue layer between adjacent bare batteries and the partition, so as to relatively fix the two adjacent bare batteries and prevent sliding between the bare batteries, which can not only improve the qualified rate of the packaged inner series batteries, but also improve the drop performance; at the same time, the two adjacent glue layers are staggered, and only the thickness of one glue layer needs to be calculated in the thickness calculation, which reduces the thickness of the inner series battery cells and improves the energy density. Therefore, the thickness difference of the inner series batteries is reduced and the flatness is improved.

[0037] Embodiment 2

[0038] This embodiment provides an inner-series battery, which includes the inner-series battery cell described in the first embodiment, and the inner-series battery cell is encapsulated in a shell.

[0039] In this embodiment, the outer shell is an aluminum-plastic film, and no glue layer is provided between the inner series battery cells and the outer shell.

[0040] In order to better illustrate the influence of the inner-series battery cells of the present application on the performance of the inner-series battery, multiple samples of the inner-series battery are provided below for detailed description.

[0041] Sample 1

[0042] The inner-series battery provided by Sample 1 includes an inner-series battery cell and an outer shell, wherein the inner-series battery cell is encapsulated in the outer shell.

[0043] Among them, the inner series battery cell includes 2 bare battery cells and 1 partition, the bare battery cell, the partition, and the bare battery cell are stacked in sequence, the two bare battery cells overlap, and the pole ears of the two bare battery cells are flipped symmetrically. Among them, a single layer of glue is provided between adjacent bare battery cells and the partition to connect the bare battery cells and the partition, and no glue layer is provided between the bare battery cells and the outer shell. That is, the inner series battery cell includes two layers of glue, and the adjacent two layers of glue are staggered.

[0044] The length L1 of the bare cell is 80mm, and the width W1 is 65mm. The adhesive layer is rectangular, with a length L2 of 52mm, a width W2 of 10mm, and a thickness of 28μm. The distance D1 between one adhesive layer and the first side of the bare cell along the width direction is 15mm, and the distance D2 between the other adhesive layer and the first side of the bare cell along the width direction is 45mm. By calculation, it can be seen that the area S1 of the bonded surface of the bare cell is 5200mm 2 The adhesive surface area S2 is 520 mm 2 , the ratio of S2 to S1 is 0.1.

[0045] Sample 2

[0046] Compared with Sample 1, in the inner-series battery provided by Sample 2, a single layer of glue is provided between the bare cell and the outer shell, that is, the inner-series cell includes a total of four layers of glue, and the two adjacent layers of glue are staggered.

[0047] Sample 3

[0048] Compared with Sample 1, in the inner-series battery provided by Sample 3, no glue layer is arranged between adjacent bare cells and the partition, and a single glue layer is arranged between the bare cells and the outer shell, that is, the inner-series cells include two glue layers in total, and the two adjacent glue layers are staggered.

[0049] Sample 4

[0050] Compared with Sample 1, in the inner-series battery provided by Sample 4, no adhesive layer is provided between adjacent bare cells and partitions, and between the bare cells and the outer casing.

[0051] Sample 5

[0052] Compared with sample 1, the length L2 of the glue layer in the inner series battery provided by sample 5 is 31.22mm and the width W2 is 5mm. Through calculation, it can be known that the area S2 of the adhesive surface of the glue layer is 156mm 2 , the ratio of S2 to S1 is 0.03.

[0053] Sample 6

[0054] Compared with sample 1, the length L2 of the glue layer in the inner series battery provided by sample 6 is 32.5mm and the width W2 is 8mm. Through calculation, it can be known that the area S2 of the adhesive surface of the glue layer is 260mm 2 , the ratio of S2 to S1 is 0.05.

[0055] Sample 7

[0056] Compared with sample 1, the length L2 of the glue layer in the inner series battery provided by sample 7 is 78mm and the width W2 is 10mm. Through calculation, it can be known that the area S2 of the adhesive surface of the glue layer is 364mm 2 , the ratio of S2 to S1 is 0.07.

[0057] Sample 8

[0058] Compared with sample 1, the length L2 of the glue layer in the inner series battery provided by sample 8 is 31.2mm and the width W2 is 5mm. Through calculation, it can be known that the area S2 of the adhesive surface of the glue layer is 780mm 2 , the ratio of S2 to S1 is 0.15.

[0059] Sample nine

[0060] Compared with sample 1, the inner series battery provided by sample 9 has a length L2 of 20 mm and a width W2 of 20 mm. Through calculation, it can be known that the area S2 of the adhesive surface of the adhesive layer is 10400 mm 2 , the ratio of S2 to S1 is 0.2.

[0061] Sample 10

[0062] Compared with sample one, in the inner series battery provided by sample ten, the two adjacent layers of glue are overlapped.

[0063] The internal series batteries of samples 1 to 4 above were subjected to directional drop tests (dropped from the six sides and four corners of the battery cell respectively). The test results are as follows:

[0064]

[0065] Comparing samples 1 to 4, the difference lies in the different locations of the adhesive layer. Combined with the test results, sample 1 has the highest test pass rate and the best drop performance, indicating that the location of the adhesive layer of sample 1 is optimal.

[0066] Compared with Sample 1, Sample 2 adds a layer of glue between the bare cell and the outer shell. Since the bare cell and the outer shell are not completely bonded, the outer shell is easily damaged when the bare cell moves, thus affecting the drop performance and safety performance.

[0067] Compared with Sample 1, Sample 3 has the glue layer set between the bare battery cell and the shell. Since the bare battery cells are not relatively fixed, they are very likely to move, thus affecting the drop performance and safety performance.

[0068] Compared with sample 1, sample 4 does not have a glue layer, and the two bare cells are very likely to move around, thus affecting the drop performance and safety performance.

[0069] In addition, the internal series batteries of sample 1 and samples 5 to 9 were subjected to directional drop tests (dropped from the six sides and four corners of the battery cell respectively). The test results are as follows:

[0070]

[0071] Comparing sample 1 and samples 5 to 9, the difference lies in the different areas of the adhesive surface of the adhesive layer. Combined with the test results, as the area of ​​the adhesive surface of the adhesive layer increases, the greater the ratio of the area of ​​the adhesive surface to the area of ​​the bare cell, the higher the test pass rate. When the ratio of the area of ​​the adhesive surface of the adhesive layer to the area of ​​the bare cell is above 0.1, the test pass rate is as high as 100%, indicating that the ratio of the area of ​​the adhesive surface of the adhesive layer to the area of ​​the bare cell must be above 0.1.

[0072] Take the inner series batteries of sample 1 and sample 10, disassemble the batteries after battery formation, and observe the interface. The observation results are as follows:

[0073]

[0074]

[0075] Comparing sample one and sample ten, the difference lies in the different arrangements of the two adjacent layers of glue, that is, whether the two adjacent layers of glue overlap. Combined with the test results, the glue layers in the inner series battery of sample one are staggered, and the thickness calculation only needs to calculate the thickness of one layer of glue, so that the thickness difference of the inner series battery cells is small, the flatness is high, the energy density is improved, and there will be no lithium precipitation black spots. On the contrary, the glue layers in the inner series battery of sample ten overlap, resulting in a large thickness at this position, and a large difference in thickness with other positions, poor flatness of the battery cell, uneven pressure during battery formation, resulting in a decrease in energy density, and obvious black spots appearing at the glue sticking position.

[0076] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. An internal series battery cell, characterized in that: The invention comprises a bare battery cell (1) and a partition (2), wherein the number of the bare battery cells (1) is N, and the number of the partitions (2) is N-1, wherein N≥2; the bare battery cells (1) and the partitions (2) are alternately stacked in sequence, and adjacent bare battery cells (1) and partitions (2) are connected via an adhesive layer (3), and two adjacent layers of the adhesive layer (3) are staggered.

2. The inner series battery cell according to claim 1, characterized in that: The adhesive layer (3) is rectangular in shape.

3. The inner series battery cell according to claim 2, characterized in that: The adhesive layer (3) is arranged along the length direction of the bare battery core (1).

4. The inner series battery cell according to claim 2, characterized in that: The positional relationship between two adjacent layers of the adhesive layer (3) satisfies the following relationship: D1+W2<D2, wherein D1 is the distance between one of the two adjacent layers of the adhesive layer (3) and the first side edge (11) of the bare battery cell (1) along the width direction, D2 is the distance between the other of the two adjacent layers of the adhesive layer (3) and the first side edge (11) of the bare battery cell (1) along the width direction, and W2 is the width of the adhesive layer (3).

5. The inner series battery cell according to claim 2, characterized in that: The length of the adhesive layer (3) satisfies the following relationship: 0.2L1<L2<L1, wherein L1 is the length of the bare battery cell (1), and L2 is the length of the adhesive layer (3).

6. The inner series battery cell according to claim 2, characterized in that: The width of the adhesive layer (3) satisfies the following relationship: 0.1W1<W2<0.5W1, wherein W1 is the width of the bare battery cell (1), and W2 is the width of the adhesive layer (3).

7. The inner series battery cell according to any one of claims 1 to 6, characterized in that: The bonding area of ​​the adhesive layer (3) satisfies the following relationship: S2 / S1≥0.1, wherein S1 is the area of ​​the bonded surface of the bare battery cell (1), and S2 is the area of ​​the bonding surface of the adhesive layer (3).

8. The inner series battery cell according to any one of claims 1 to 6, characterized in that: The thickness of the adhesive layer (3) is 20 to 120 μm.

9. The inner series battery cell according to any one of claims 1 to 6, characterized in that: The number of the adhesive layers (3) arranged between the adjacent bare cells (1) and the partitions (2) is one layer.

10. An internal series battery, characterized in that: It comprises an inner-series battery cell as described in any one of claims 1 to 9, wherein the inner-series battery cell is encapsulated in a shell.

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