Battery cell assembly, battery comprising battery cell assembly and electric equipment

Abstract

The utility model discloses a battery cell assembly, a battery comprising the battery cell assembly and electric equipment, the battery cell assembly comprises positive plates and negative plates which are alternately stacked; the positive plate comprises a positive active layer and an insulating layer surrounding the periphery of the positive active layer; the negative plate comprises a negative active layer; wherein the orthographic projection of the positive electrode active layer on the projection surface is located in the orthographic projection of the negative electrode active layer on the projection surface, and the orthographic projections of the peripheral edges of the negative electrode active layer on the projection surface are all located in the orthographic projection of the insulating layer on the projection surface, and the projection plane is perpendicular to the stacking direction of the positive plate and the negative plate. The insulating layer in the positive plate is designed to exceed the active material layer in the negative plate, so that the positive plate and the negative plate can be isolated, burrs on the edge of the positive plate are prevented from puncturing the diaphragm, the stability of the battery performance is ensured, and the safety performance of the battery is improved.

Description

Technical Field

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

[0002] After decades of development, lithium-ion batteries have been widely used in digital, power tools, aerospace, energy storage and other fields. While improving energy density, how to ensure safety has always been a hot topic for professionals in this field.

[0003] When designing lithium-ion batteries, it is considered that if the negative electrode has no position to receive lithium ions, lithium ions will precipitate on the surface of the negative electrode to form lithium dendrites and pierce the diaphragm, causing a short circuit in the battery and thermal runaway. Existing laminated lithium-ion batteries are usually designed with the edge of the negative electrode extending beyond the edge of the positive electrode (i.e., overhang). However, when cutting the positive electrode sheet, lithium-ion batteries with this structure are prone to burrs on the cut surface of the positive electrode sheet, which may pierce the diaphragm and cause a short circuit between the positive and negative electrodes. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a battery cell assembly, a battery comprising the battery cell assembly and an electrical device, which solves the problem in the prior art that the burrs on the cut surface of the positive electrode sheet of the lithium-ion battery easily pierce the diaphragm, causing a short circuit between the positive and negative electrodes.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A battery cell assembly, the battery cell assembly comprising alternately stacked positive electrode sheets and negative electrode sheets; adjacent positive electrode sheets and negative electrode sheets are separated by a separator;

[0007] The positive electrode sheet comprises a positive electrode current collector, and both sides of the positive electrode current collector are provided with a positive electrode active layer and an insulating layer arranged around the periphery of the positive electrode active layer;

[0008] The negative electrode sheet comprises a negative electrode current collector, and negative electrode active layers are arranged on both sides of the negative electrode current collector;

[0009] The orthographic projection of the positive electrode active layer on the projection plane is located within the orthographic projection of the negative electrode active layer on the projection plane, and the orthographic projections of the four edges of the negative electrode active layer on the projection plane are all located within the orthographic projection of the insulating layer on the projection plane, wherein the projection plane is perpendicular to the stacking direction of the positive electrode sheet and the negative electrode sheet.

[0010] Optionally, on the projection surface, the negative electrode active layer has a first edge and a second edge arranged opposite to each other along a first direction; the insulating layer has a first outer edge and a second outer edge arranged opposite to each other along the first direction, and the first outer edge is arranged closer to the first edge than the second outer edge; wherein the distance between the first outer edge of the insulating layer and the first edge of the negative electrode active layer and the distance between the second outer edge of the insulating layer and the second edge of the negative electrode active layer are both G1, and the width of the negative electrode active layer in the first direction is W1, G1

[0011] / W1 = 0.25% to 1.5%; the first direction is perpendicular to the stacking direction of the positive electrode sheet and the negative electrode sheet.

[0012] Optionally, on the projection surface, the negative electrode active layer has a third edge and a fourth edge arranged opposite to each other along the second direction; the insulating layer has a third outer edge and a fourth outer edge arranged opposite to each other along the second direction, and the third outer edge is arranged closer to the third edge than the fourth outer edge; wherein the distance between the third outer edge of the insulating layer and the third edge of the negative electrode active layer and the distance between the fourth outer edge of the insulating layer and the fourth edge of the negative electrode active layer are both G2, and the length of the negative electrode active layer in the second direction is L1, G2

[0013] / L1 = 0.25% to 1.5%; the second direction is perpendicular to the stacking direction of the positive electrode sheet and the negative electrode sheet, and the first direction and the second direction are perpendicular to each other.

[0014] Optionally, in the stacking direction of the positive electrode sheet and the negative electrode sheet, the thickness of the insulating layer is 30% to 100% of the thickness of the positive electrode active layer.

[0015] Optionally, one end of the negative electrode current collector in the second direction is connected to a negative electrode ear; in the first direction, the width of the negative electrode current collector is equal to the width of the negative electrode active layer; in the second direction, the length of the negative electrode current collector is equal to the length of the negative electrode active layer.

[0016] Optionally, a positive electrode ear is connected to one end of the positive electrode collector in the second direction; in the first direction, the width of the positive electrode collector is equal to the distance between the first outer edge and the second outer edge of the insulating layer; in the second direction, the length of the positive electrode collector is equal to the distance between the third outer edge and the fourth outer edge of the insulating layer.

[0017] Optionally, the positive electrode tab is provided with a first detection hole; and the negative electrode tab is provided with a second detection hole.

[0018] Optionally, in the first direction, both ends of the positive electrode active layer are connected to the insulating layer; in the second direction, both ends of the positive electrode active layer are connected to the insulating layer.

[0019] The utility model also provides a battery, comprising the battery core assembly as described in any one of the above items.

[0020] The utility model also provides an electrical device, comprising the battery as described in any one of the above items.

[0021] Compared with the prior art, the utility model has the following beneficial effects:

[0022] The utility model provides a battery cell assembly, a battery including the battery cell assembly, and an electrical device. By designing the insulating layer in the positive electrode sheet to extend beyond the active material layer in the negative electrode sheet, on the one hand, the risk of short circuit caused by the burrs on the edge of the positive electrode sheet piercing the diaphragm and contacting the negative electrode sheet can be avoided; on the other hand, it can ensure that the edge of the negative electrode sheet is always located between the insulating layers of two adjacent positive electrode sheets during the charge and discharge process of the battery, thereby ensuring that the edge of the negative electrode sheet is always supported during the charge and discharge process of the battery to avoid cracking and powdering. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the related technologies, the drawings required for use in the specific implementation methods or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A schematic diagram of the structure of a battery core assembly provided by the utility model;

[0025] Figure 2 A schematic diagram of the structure of a negative electrode sheet in a battery cell assembly provided by the utility model;

[0026] Figure 3 A schematic diagram of the structure of a positive electrode sheet in a battery core assembly provided by the utility model;

[0027] Figure 4 A cross-sectional view of a battery core assembly provided by the utility model;

[0028] Figure 5 This is another cross-sectional view of a battery core assembly provided by the utility model.

[0029] In the above figure: 1, positive electrode sheet; 11, positive electrode ear; 12, positive electrode active layer; 13, insulating layer; 131, first outer edge; 132, second outer edge; 133, third outer edge; 134, fourth outer edge; 2, negative electrode sheet; 21, negative electrode ear; 22, negative electrode active layer; 221, first edge; 222, second edge; 223, third edge; 224, fourth edge. DETAILED DESCRIPTION

[0030] In order to make the purpose, features and advantages of the utility model more obvious and easy to understand, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the embodiment described below is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] In the description of the present utility model, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a centrally arranged component at the same time.

[0032] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0033] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0034] In a laminated battery, when the edge of the negative electrode exceeds the edge of the positive electrode, on the one hand, when cutting the positive electrode sheet, burrs are easily generated on the cut surface of the positive electrode sheet, and the burrs may pierce the separator between the positive and negative electrodes, causing a short circuit between the positive and negative electrodes. On the other hand, due to the material characteristics of the negative electrode, most of the expansion of the battery cell is contributed by the negative electrode material (such as graphite, silicon carbon, silicon oxygen, etc.). Due to the overhang setting, the difference in expansion stress between the negative electrode material and the body may cause the edge of the electrode sheet to crack and shed powder during the charge and discharge process.

[0035] The utility model aims to provide a battery core assembly to solve the problem in the prior art that lithium-ion batteries are prone to piercing the diaphragm due to burrs on the cut surface of the positive electrode plate, causing a short circuit between the positive and negative electrodes, and cracking and powdering of the edge of the plate during charging and discharging.

[0036] Please refer to Figures 1 to 3 To achieve the above purpose, the utility model provides the following technical solutions:

[0037] A battery cell assembly comprises alternately stacked positive electrode sheets 1 and negative electrode sheets 2, wherein adjacent positive electrode sheets 1 and negative electrode sheets 2 are separated by a separator.

[0038] In this embodiment, the positive electrode sheet 1 includes a positive electrode collector, both sides of which are provided with a positive electrode active layer 12, and an insulating layer 13 arranged around the outer periphery of the positive electrode active layer 12; wherein one end of the positive electrode collector in the second direction is connected to a positive electrode ear 11.

[0039] The negative electrode sheet 2 includes a negative electrode current collector, and negative electrode active layers 22 are disposed on both sides of the negative electrode current collector; wherein, one end of the negative electrode current collector in the second direction is connected to a negative electrode ear.

[0040] It can be understood that the positive electrode active layer 12 , the insulating layer 13 and the negative electrode active layer 22 are all coating layers formed by coating.

[0041] Please refer to Figure 4 , Figure 5 Specifically, the orthographic projection of the positive electrode active layer 12 on the projection plane is located within the orthographic projection of the negative electrode active layer 22 on the projection plane, and the orthographic projections of the four edges of the negative electrode active layer 22 on the projection plane are all located within the orthographic projection of the insulating layer 13 on the projection plane, wherein the projection plane is perpendicular to the stacking direction of the positive electrode sheet 1 and the negative electrode sheet 2.

[0042] In the present embodiment, by making the insulating layer 13 of the positive electrode sheet 1 extend beyond the edges of the negative electrode active layer 22, on the one hand, it is possible to avoid the situation where burrs are generated on the edge of the positive electrode active layer 12 and pierce the diaphragm, thereby preventing the positive and negative electrodes from short-circuiting; on the other hand, although the negative electrode active layer 22 expands and contracts in the first direction and the second direction during the charge and discharge process of the battery, the edge of the negative electrode sheet is always located between the insulating layers of the two adjacent positive electrode sheets during the charge and discharge process of the battery, that is, during the charge and discharge process of the battery, the edge of the negative electrode sheet is always supported, thereby avoiding the problem of cracking and powdering caused by the suspended design of the negative electrode active layer 22 and the expansion and contraction of the negative electrode active layer 22 during the charge and discharge process of the battery, thereby improving the safety of the battery cell.

[0043] In addition, since the orthographic projection of the positive electrode active layer 12 on the plane where the insulating layer 13 is located is located within the range of the orthographic projection of the negative electrode active layer 22 on the plane where the insulating layer 13 is located, the edge of the negative electrode active layer 22 is designed to exceed the edge of the positive electrode active layer 12, so that all positive electrode active materials have corresponding negative electrode active materials relative to each other, thereby avoiding waste of positive electrode active materials.

[0044] Further, in this embodiment, on the projection plane, the negative electrode active layer 22 has a first edge 221 and a second edge 222 arranged opposite to each other along the first direction; the insulating layer 13 has a first outer edge 131 and a second outer edge 132 arranged opposite to each other along the first direction, and the first outer edge 131 is arranged closer to the first edge 221 than the second outer edge 132; wherein the distance between the first outer edge 131 of the insulating layer 13 and the first edge 221 of the negative electrode active layer 22 and the distance between the second outer edge 132 of the insulating layer 13 and the second edge 222 of the negative electrode active layer 22 are both G1, and the width of the negative electrode active layer 22 in the first direction is W1, G1 / W1=0.25%-1.5%; the first direction is perpendicular to the stacking direction of the positive electrode sheet 1 and the negative electrode sheet 2;

[0045] The negative electrode active layer 22 has a third edge 223 and a fourth edge 224 that are arranged opposite to each other along the second direction; the insulating layer 13 has a third outer edge 133 and a fourth outer edge 134 that are arranged opposite to each other along the second direction, and the third outer edge 133 is arranged closer to the third edge 223 than the fourth outer edge 134; wherein the distance between the third outer edge 133 of the insulating layer 13 and the third edge 223 of the negative electrode active layer 22 and the distance between the fourth outer edge 134 of the insulating layer 13 and the fourth edge 224 of the negative electrode active layer 22 are both G2, and the length of the negative electrode active layer 22 in the second direction is L1, G2 / L1=0.25%-1.5%; the second direction is perpendicular to the stacking direction of the positive electrode sheet 1 and the negative electrode sheet 2;

[0046] The first direction and the second direction are perpendicular to each other.

[0047] In this embodiment, the following effects can be achieved through the above-mentioned structure: since the negative electrode sheet 2 will expand and shrink in the first direction and the second direction during the battery charging and discharging process, when G1 / W1 and G2 / L1 are both greater than and equal to 0.25%, it can be ensured that the insulating layer 13 plays a good supporting role during the battery charging and discharging process; and when G1 / W1 and G2 / L1 are both less than and equal to 1.5%, it can not only avoid the risk of short circuit caused by the burrs on the edge of the positive electrode sheet 1 piercing the diaphragm and contacting the negative electrode sheet, but also avoid the problem of cracking and powdering caused by the suspended design of the negative electrode active layer 22 and the expansion and contraction of the negative electrode active layer 22 during the battery charging and discharging process; and it can also avoid the waste of space caused by the insulating layer 13 exceeding the edges of the negative electrode sheet 2 too much.

[0048] It should be noted that G1 / W1 can be 0.3% or 0.35% or 0.4% or 0.45% or 0.5% or 0.55% or 0.6% or 0.65% or 0.7% or 0.8% or 0.9% or 1.1% or 1.3% or 1.4%; G2 / L1 can be 0.33% or 0.46% or 0.57% or 0.62% or 0.68% or 0.73% or 0.79% or 0.84% ​​or 0.89% or 0.99% or 1.14% or 1.23% or 1.36% or 1.49%; in addition, in order to facilitate coating, G1 / W1=G2 / L1 can be designed.

[0049] Furthermore, in this embodiment, in the stacking direction of the positive electrode sheet 1 and the negative electrode sheet 2, the thickness of the insulating layer 13 is 30% to 100% of the thickness of the positive electrode active layer 12. When the thickness of the insulating layer 13 meets the aforementioned conditions, it can play a supporting role while ensuring the insulation effect, thereby reducing the influence of the negative electrode expansion stress.

[0050] Specifically in this embodiment, the insulating layer 13 and the positive electrode active layer 12 have a flat surface in the third direction perpendicular to the first direction, that is, the thickness of the insulating layer 13 is equal to the thickness of the positive electrode active layer 12, so that the insulating layer 13 can better constrain the edge of the negative electrode active layer 22 and prevent the edge of the negative electrode active layer 22 from cracking and powdering.

[0051] Further, in this embodiment, in the first direction, the width of the negative electrode current collector is equal to the width of the negative electrode active layer 22; in the second direction, the length of the negative electrode current collector is equal to the length of the negative electrode active layer 22;

[0052] In the first direction, the width of the positive electrode collector is equal to the distance between the first outer edge 131 and the second outer edge 132 of the insulating layer 13 ; in the second direction, the length of the positive electrode collector is equal to the distance between the third outer edge 133 and the fourth outer edge 134 of the insulating layer 13 .

[0053] In this embodiment, the edges of the negative electrode current collector except the negative electrode tab are designed not to exceed the negative electrode active layer 22, and the edges of the positive electrode current collector except the positive electrode tab are designed not to exceed the insulating layer 13, which can avoid space waste.

[0054] Furthermore, in this embodiment, in the first direction, both ends of the positive electrode active layer 12 are connected to the insulating layer 13; in the second direction, both ends of the positive electrode active layer 12 are connected to the insulating layer 13, which can further avoid space waste.

[0055] Furthermore, in this embodiment, the positive electrode ear is provided with a first detection hole; the negative electrode ear is provided with a second detection hole, and the first detection hole and the second detection hole are used to check whether the stacking is misaligned after the laminated battery is manufactured. If the first detection holes of the stacked positive electrode ears and the first detection holes of the stacked negative electrode ears are arranged opposite to each other, it is qualified.

[0056] Furthermore, both edges of the positive electrode active layer 12 in the third direction are provided with rounded corners. The design of the rounded corners can further prevent the positive electrode sheet 1 from piercing the separator, thereby improving the reliability of the battery.

[0057] Based on the aforementioned embodiments, an embodiment of the utility model further provides a battery, comprising a battery cell assembly as described in any one of the above items.

[0058] Based on the above embodiments, the present invention further provides an electrical device, comprising the battery as described in the above embodiments.

[0059] As described above, the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A battery cell assembly, characterized in that: The battery cell assembly comprises positive electrode sheets (1) and negative electrode sheets (2) stacked alternately; adjacent positive electrode sheets (1) and negative electrode sheets (2) are separated by a separator; The positive electrode sheet (1) comprises a positive electrode current collector, and both sides of the positive electrode current collector are provided with a positive electrode active layer (12) and an insulating layer (13) arranged around the outer periphery of the positive electrode active layer (12); The negative electrode sheet (2) comprises a negative electrode current collector, and negative electrode active layers (22) are arranged on both sides of the negative electrode current collector; The orthographic projection of the positive electrode active layer (12) on the projection plane is located within the orthographic projection of the negative electrode active layer (22) on the projection plane, and the orthographic projections of the four edges of the negative electrode active layer (22) on the projection plane are all located within the orthographic projection of the insulating layer (13) on the projection plane, wherein the projection plane is perpendicular to the stacking direction of the positive electrode sheet (1) and the negative electrode sheet (2).

2. The battery cell assembly according to claim 1, characterized in that: On the projection surface, the negative electrode active layer (22) has a first edge and a second edge arranged opposite to each other along a first direction; the insulating layer (13) has a first outer edge and a second outer edge arranged opposite to each other along the first direction, and the first outer edge is arranged closer to the first edge than the second outer edge; wherein the distance between the first outer edge of the insulating layer (13) and the first edge of the negative electrode active layer (22) and the distance between the second outer edge of the insulating layer (13) and the second edge of the negative electrode active layer (22) are both G1, the width of the negative electrode active layer (22) in the first direction is W1, and G1 / W1=0.25% to 1.5%; the first direction is perpendicular to the stacking direction of the positive electrode sheet (1) and the negative electrode sheet (2).

3. The battery cell assembly according to claim 2, characterized in that: On the projection surface, the negative electrode active layer (22) has a third edge and a fourth edge arranged opposite to each other along a second direction; the insulating layer (13) has a third outer edge and a fourth outer edge arranged opposite to each other along the second direction, and the third outer edge is arranged closer to the third edge than the fourth outer edge; wherein the distance between the third outer edge of the insulating layer (13) and the third edge of the negative electrode active layer (22) and the distance between the fourth outer edge of the insulating layer (13) and the fourth edge of the negative electrode active layer (22) are both G2, the length of the negative electrode active layer (22) in the second direction is L1, and G2 / L1=0.25%-1.5%; the second direction is perpendicular to the stacking direction of the positive electrode sheet (1) and the negative electrode sheet (2), and the first direction and the second direction are perpendicular to each other.

4. The battery cell assembly according to claim 3, characterized in that: In the stacking direction of the positive electrode sheet (1) and the negative electrode sheet (2), the thickness of the insulating layer (13) is 30% to 100% of the thickness of the positive electrode active layer (12).

5. The battery core assembly according to any one of claims 2 to 4, characterized in that: One end of the negative electrode current collector in the second direction is connected to a negative electrode ear; in the first direction, the width of the negative electrode current collector is equal to the width of the negative electrode active layer (22); in the second direction, the length of the negative electrode current collector is equal to the length of the negative electrode active layer (22).

6. The battery cell assembly according to claim 5, characterized in that: One end of the positive electrode collector in the second direction is connected to a positive electrode ear; in the first direction, the width of the positive electrode collector is equal to the distance between the first outer edge and the second outer edge of the insulating layer (13); in the second direction, the length of the positive electrode collector is equal to the distance between the third outer edge and the fourth outer edge of the insulating layer (13).

7. The battery cell assembly according to claim 6, characterized in that: The positive electrode tab is provided with a first detection hole; the negative electrode tab is provided with a second detection hole.

8. The battery core assembly according to claim 3 or 4, characterized in that: In the first direction, both ends of the positive electrode active layer (12) are connected to the insulating layer (13); in the second direction, both ends of the positive electrode active layer (12) are connected to the insulating layer (13).

9. A battery, characterized in that: Comprising the battery core assembly as described in any one of claims 1 to 8.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

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