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Polyamide-imide coated separators for high energy rechargeable lithium batteries

A rechargeable lithium battery, polyamide technology, applied in the field of polyamide coating separator, polyamide-imide coating film, polyamide-imide battery separator, can solve the problem of thermal runaway of lithium battery

Pending Publication Date: 2021-12-31
CELGARD LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Other shorts, such as hard shorts, can cause thermal runaway in lithium batteries, which is a serious safety concern for lithium rechargeable batteries

Method used

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  • Polyamide-imide coated separators for high energy rechargeable lithium batteries
  • Polyamide-imide coated separators for high energy rechargeable lithium batteries
  • Polyamide-imide coated separators for high energy rechargeable lithium batteries

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1 and 2

[0120] As a first step, a coating solution was prepared by mixing PVDF-HFP with less than 20% HFP and polyamide-imide (Solvay Torlon) in NMP. The solution was amber but clear, which was surprising since, as demonstrated in Comparative Example 2, polyimide and PVDF are generally immiscible.

[0121] Next, the coating solution is applied to one side of the porous polymer base membrane. In this example, using 2500PP base film. After coating, there are two methods to remove NMP. One is oven drying, and the other is extracting NMP in a water bath, followed by air drying. The latter method is preferred because it is faster, more efficient and better film-forming. figure 2 The entire laboratory coating process using the water extraction process is shown.

[0122] Two separate samples were produced using different NMP removal methods. The resulting separator thickness (base film + coating) and Gurley value (seconds) were measured and appearance was determined visually at 15X m...

Embodiment 3-5

[0124] Coating solutions were prepared in the same manner as in Examples 1 and 2. In Examples 3 and 4, the ratio of PAI / PVDF is as follows Figure 4 shown in the table. In Examples 3-5, the coating was applied on the base film 2500 on. In each of Examples 3-5, the solvent (NMP) was removed by overnight air drying using water chase. Dipping times vary between 2 and 5 minutes. Such as Figure 4 As shown in the table, a longer immersion time of 5 minutes resulted in a lower Gurley's coating. It is believed that the ER of Example 4 would also be lower than that of Example 3, but was not measured. Figure 4 The table in also shows that higher PAI / PVDF ratios result in lower ER membranes (compare Examples 3 and 5 with the same water immersion time). Comparative Example 1 shows the shrinkage and ER of an uncoated 2500 base film. The ER of the coated films was measured by soaking the coated films in electrolyte for 1 h to expand the PVDF. Figure 5A and 5B SEMs of the base ...

Embodiment 6 and 7 and comparative example 2

[0127] Refer to Examples 6-8 and Comparative Example 2 similarly to Examples 1 and 2, except that in Comparative Example 2, polyimide (PI) was used instead of polyamide-imide (PAI). as follows Figure 7 As shown in the table in , solvent removal or substantial removal was achieved. SEM of these examples shows that the water immersion process produces the smoothest coating, which is more preferred for battery separators. Compare Examples 6 and 7. It also shows that the films formed by substituting PI for PAI do not work. PI is not miscible with PVDF at all. This is even evidenced by the naked eye appearance of the coating. Compare Comparative Example 2 and Example 6. See Figure 7 .

[0128] Description of non-limiting example lithium batteries:

[0129] Cylindrical lithium iron disulfide batteries use lithium as the anode, iron disulfide as the cathode, and a lithium salt in an organic solvent mixture as the electrolyte. The figure below shows the cross-section of a t...

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Abstract

The instant disclosure or invention is preferably directed to a polyamide-imide coated membrane, separator membrane, or separator for a lithium battery such as a high energy or high voltage rechargeable lithium battery and the corresponding battery. The separator preferably includes a porous or microporous polyamide-imide coating or layer on at least one side of a polymeric microporous layer, membrane or film. The polyamide-imide coating or layer may include other polymers, additives, fillers, or the like. The polyamide-imide coating may be adapted, for example, to provide oxidation resistance, to block dendrite growth, to add dimensional and / or mechanical stability, to reduce shrinkage, to add high temperature performance (HTMI function), to prevent electronic shorting at temperatures above 200 deg C, and / or the like. The microporous polymeric base layer may be adapted, at least, to hold liquid, gel, or polymer electrolyte, to conduct ions, and / or to block ionic flow between the anode and the cathode in the event of thermal runaway (shutdown function). The polyamide-imide coated separator may be adapted, for example, to keep the electrodes apart at high temperatures, to provide oxidation resistance, to block dendrite growth, to add dimensional stability, to reduce shrinkage, to add high temperature performance (HTMI function), to prevent electronic shorting at temperatures above 200 deg C, to increase puncture strength, and / or to block ionic flow between the anode and the cathode in the event of thermal runaway (shutdown function). Although secondary lithium battery usage may be preferred, the instant polyamide-imide coated membrane may be used in a battery, cell, primary battery, capacitor, fuel cell, textile, filter, and / or composite, and / or as a layer or component in other applications, devices, and / or the like.

Description

technical field [0001] The present disclosure or invention is preferably directed to polyamide-imide coated films, separator films or separators for lithium batteries, such as high energy or high voltage rechargeable lithium batteries, and corresponding batteries. The separator preferably comprises a porous or microporous polyamide-imide coating or layer on at least one side of the polymeric microporous layer, membrane or film. The polyamide-imide coating or layer may include other polymers, additives, fillers, or the like. Polyamide-imide coatings can be adapted, for example, to provide oxidation resistance, prevent dendrite growth, increase dimensional and / or mechanical stability, reduce shrinkage, increase high temperature performance (HTMI functionality), prevent temperature at which electrical shorts and / or the like occur. The microporous polymeric substrate can be adapted at least to accommodate liquid, gel, or polymer electrolytes, to conduct ions, and / or to prevent i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/423H01M50/449H01M50/457H01M50/417H01M4/13H01M10/052H01M10/0562H01M10/0565H01M50/403H01M50/426H01M50/451H01M50/489H01M50/491H01M50/497
CPCY02E60/10H01M50/403H01M50/449H01M50/417H01M50/451H01M50/457H01M50/491H01M50/489H01M50/426H01M50/423H01M50/497H01M50/429H01M10/0525H01M50/414H01M10/052
Inventor 张正铭长青·王·亚当斯斯蒂芬·雷纳兹
Owner CELGARD LLC