Electrode assembly and electrochemical device

An electrode assembly and negative electrode technology, applied in the field of electrochemical devices, can solve the problems of undervoltage in the cell area, poor surface consistency of the pole piece, thermal runaway of internal short circuit, etc., so as to improve the undervoltage problem, prevent the short circuit, reduce the Effects of Risk of Lithium Precipitation Problems

Pending Publication Date: 2021-12-21
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in this structure, there is a large local thickness difference at the groove position, which makes the consistency of the surface of the pole piece worse, resulting in undervoltage in some areas during the cell and formation process, and poor interfacial infiltration in the defect area in the later stage of the cell cycle. Lithium analysis problem, prone to thermal runaway caused by internal short circuit

Method used

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  • Electrode assembly and electrochemical device
  • Electrode assembly and electrochemical device
  • Electrode assembly and electrochemical device

Examples

Experimental program
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Effect test

Embodiment 1

[0076] see figure 1 , figure 2 with image 3 , the electrode assembly 100 includes a positive electrode sheet 10 , a negative electrode sheet 20 , a separator 30 , a positive electrode tab 41 and a negative electrode tab 42 . The positive electrode sheet 10 and the negative electrode sheet 20 are stacked and wound, and the separator 30 is disposed between the positive electrode sheet 10 and the negative electrode sheet 20 . The positive tab 41 is electrically connected to the positive tab 10 , and the negative tab 42 is electrically connected to the negative tab 20 .

[0077] Specifically, see figure 2 , the positive electrode sheet 10 includes a positive electrode current collector 11 and a positive electrode active material layer 12 disposed on the surface of the positive electrode current collector 11 . In this embodiment, the positive electrode active material layers 12 are respectively provided on opposite sides of the positive electrode current collector 11 . The ...

no. 2 example

[0092] see Figure 4 , Figure 5 with Image 6 , the electrode assembly 200 of the second embodiment is substantially the same as the electrode assembly 100 of the first embodiment, the difference is that the negative electrode sheet 20 of the electrode assembly 200 is not provided with a second insulation covering the second groove 23 and the fourth groove 24 70 pieces. Since the second insulating member 70 is omitted, the size of the first insulating member 60 can be reduced correspondingly, which is beneficial to improve the energy density of the electrode assembly 200 .

[0093] In the second embodiment, the dimensional relationship between the second groove 23 and the first protective glue 50 satisfies: 1mm≤L2-L1≤5mm, 1mm≤W2-W1≤5mm, 0μm≤T2-T1≤20μm.

[0094] The dimensional relationship between the first insulating member 60 and the second groove 23 satisfies 1mm≤L4-L2≤10mm, 1mm≤W4-W2≤10mm.

no. 3 example

[0096] see Figure 7 , Figure 8 with Figure 9 The electrode assembly 300 of the third embodiment is substantially the same as the electrode assembly 100 of the first embodiment, the difference is that in the electrode assembly 300, the first protective glue 50 fills the second groove 23 and the fourth groove 24 in an equal area, The peripheral side of the first protective glue 50 is in contact with the negative electrode active material layer 22 to eliminate the gap between the first protective glue 50 and the periphery of the second groove 23 or the fourth groove 24 . The first protective glue 50 will not produce fluidity after curing, and eliminating the gap in the groove is beneficial to avoid the overflow of the active material when the subsequent electrode assembly 300 is under pressure, and improve the pressure resistance and service life of the electrode assembly 300 .

[0097] see again Figure 8 with Figure 9 , the width of the first protective glue 50 is W1, a...

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Abstract

The invention provides an electrode assembly. The electrode assembly comprises a positive plate, a negative plate, an isolating membrane and a positive tab, the positive plate comprises a positive current collector and a positive active material layer arranged on the surface of the positive current collector, the negative plate comprises a negative current collector and a negative active material layer arranged on the surface of the negative current collector, and the isolating membrane is arranged between the positive plate and the negative plate. A first groove is formed in the positive electrode active material layer, and one end of the positive electrode tab is arranged in the first groove and is electrically connected with the positive electrode current collector. The negative active material layer is provided with a second groove, the second groove corresponds to the first groove, the second groove extends to the negative current collector along the thickness direction of the electrode assembly, and first protection glue is arranged in the second groove, so that the thickness consistency of the groove and the pole piece main body area is ensured; the under-voltage problem at the tab position is improved, and the short-circuit risk is reduced. The invention further provides an electrochemical device with the electrode assembly.

Description

technical field [0001] The present application relates to the field of batteries, in particular to an electrode assembly and an electrochemical device with the electrode assembly. Background technique [0002] Lithium-ion batteries are now widely used in convenient application scenarios such as consumer electronics and power tools, and batteries with fast-charging designs account for an increasing proportion of market applications. In recent years, with the development of fast-charging batteries, a battery structure with lower internal resistance is required. On this basis, the structure of slotting in the middle of the pole piece is developed and applied, so that the tab is centered and welded in the middle of the pole piece. This structure can significantly reduce the internal resistance of the battery cell and increase the charging and discharging speed. However, in this structure, there is a large local thickness difference at the groove position, which makes the consis...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M10/058H01M10/0525H01M10/42H01M50/586
CPCH01M4/13H01M10/058H01M10/0525H01M10/4235H01M50/586Y02P70/50Y02E60/10H01M10/0587H01M50/531H01M50/59H01M50/474H01M50/489
Inventor 吴华赵义彭业军郭培培
Owner NINGDE AMPEREX TECH
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