Electrolyte for lithium batteries

Information

  • Patent Grant
  • 8883356
  • Patent Number
    8,883,356
  • Date Filed
    Thursday, June 11, 2009
    14 years ago
  • Date Issued
    Tuesday, November 11, 2014
    9 years ago
Abstract
Electrolyte and lithium secondary batteries containing the same are disclosed. In one instance, the electrolyte includes a lithium salt, a solvent and an additive. In some examples, the additive includes substances A, B and C, wherein substance A is vinylene carbonate, substance B includes at least one of fluorinated or chlorinated ethylene carbonate or diethylene carbonate, and substance C includes at least one of ethylene sulfite, 1,3-propanesultone and propenyl sulfite.
Description
CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 200810142212.8, filed Jul. 30, 2008.


BACKGROUND

Because of its high voltage and high energy density, lithium secondary batteries are widely used in various mobile electronic devices and electric tools. However, with rapidly demanding performance of portable devices on the rise, lithium-ion batteries having higher capacity, longer life and higher energy density remain challenging. Furthermore, the increasing demand places additional requirement on safety, security and performance of these batteries.


SUMMARY

Electrolytes and lithium secondary batteries containing the same are disclosed. One embodiment discloses an electrolyte having a lithium salt, a solvent, and an additive. In one embodiment, the additive includes substances A, B and C. In one embodiment, substance A has the following chemical structure:




embedded image



with R1 representing a straight-chain alkane having the general formula CnH2n+1 (0≦n≦3). In one embodiment, substance B has the chemical structure of at least one of




embedded image



with R2 representing a straight-chain alkane having the general formula CnH2n+1 (0≦n≦3), with R3 representing a straight-chain alkane having the general formula CnH2n(1≦n≦4), with R4 representing a straight-chain alkane having the general formula CnH2n+1−aYa (0≦n≦4), with R5 representing a straight-chain alkane having the general formula CnH2n+1−bZb (0≦n≦3), where X, Y and Z is selected from at least one of F and Cl, and where a and b is greater than or equal to 0, but not equal to 0 at the same time. In one embodiment, substance C includes at least one of ethylene sulfite, 1,3-propane sultone and propenyl sulfite.


In one embodiment, the solvent includes at least two members selected from the group consisting essentially of ethylene carbonate, propylene carbonate, diethylene carbonate and γ-butyrolactone. In one embodiment, the amount of additive can be from about 5% to about 40% of the electrolyte by weight. In some embodiments, the amount of substance A can be from about 0.1% to about 10% of the electrolyte by weight, the amount of substance B can be from about 0.5% to about 25% of the electrolyte by weight, and the amount of substance C can be from about 1% to about 15% of the electrolyte by weight.


In some embodiments, substance A is vinylene carbonate and R1=H, substance B is at least one of fluorinated ethylene carbonate, chloro-substituted ethylene carbonate, fluorinated diethylene carbonate and chloro-substituted diethylene carbonate, and where R2H, R3=CH2, R4=CH3 and R5=C2H4Z. In one embodiment, substance A is vinylene carbonate and R1=H, substance B is fluorinated ethylene carbonate, and substance C is propenyl sulfite. In some embodiments, the lithium salt includes at least one of lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium hexafluorophosphate (LiPF6).


One embodiment discloses a lithium battery having a shell, a battery core disposed within the shell, and an electrolyte. In this embodiment, the battery core includes an anode, a cathode and a separator disposed between the anode and the cathode. In some embodiments, the electrolyte may include the electrolyte embodiments disclosed herein.


Methods of producing an electrolyte and lithium secondary batteries containing the same are disclosed, where the electrolyte can be produced by mixing lithium salt and an additive to a solvent. In some embodiments, the additive includes the additive embodiments disclosed herein. In other embodiments, the electrolyte includes the electrolyte embodiments disclosed herein. Additionally, a lithium secondary battery can be produced by situating a separator film between a cathode and an anode to form a battery core, which can be disposed within a shell. An electrolyte may be injected within the shell, wherein the electrolyte can be produced using the methods disclosed herein. The electrolyte and the battery core may be sealed within the shell to form the lithium secondary battery.


Other variations, embodiments and features of the present disclosure will become evident from the following detailed description, drawings and claims.







DETAILED DESCRIPTION

It will be appreciated by those of ordinary skill in the art that the disclosure can be embodied in other specific forms without departing from the spirit or essential character thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive.


One embodiment discloses an electrolyte for lithium batteries having a lithium salt, a solvent, and an additive. In one embodiment, the additive includes substances A, B and C. In one example, substance A has the chemical structure




embedded image



In one example, substance B has the chemical structure of at least one of




embedded image



In one example, substance C includes at least one of ethylene sulfite (ES), 1,3-propane sultone (1,3-PS) and propenyl sulfite (PS).


In one embodiment, R1 is a straight-chain alkane having the general formula CnH2n+1, wherein 0≦n≦3. In one embodiment, R2 is a straight-chain alkane having the general formula CnH2n+1, wherein 0≦n≦3. In one embodiment, R3 is a straight-chain alkane having the general formula CnH2n, wherein 1≦n≦4. In one embodiment, R4 is a straight-chain alkane having the general formula CnH2n+1−aYa, wherein 0≦n≦4. In one embodiment, R5 is a straight-chain alkane having the general formula CnH2n+1−bZb, wherein 0≦n≦3. In some embodiments, X, Y and Z is selected from at least one of F and Cl, and a and b is greater than or equal to 0, but not equal to 0 at the same time.


In one embodiment, the amount of additives can be from about 5% to about 40% of the electrolyte by weight. In another embodiment, the amount of additives can be from about 8% to about 25% of the electrolyte by weight.


In one embodiment, the amount of substance A can be from about 0.1% to about 10% of the electrolyte by weight. In the alternative, the amount of substance A can be from about 0.5% to about 8% of the electrolyte by weight. In one embodiment, the amount of substance B can be from about 0.5% to about 25% of the electrolyte by weight. In the alternative, the amount of substance B can be from about 3% to about 15% of the electrolyte by weight. In one embodiment, the amount of substance C can be from about 1% to about 15% of the electrolyte by weight. In the alternative, the amount of substance C can be from about 3% to about 10% of the electrolyte by weight.


In some embodiments, substance A is vinylene carbonate (VC) and R1=H, substance B is at least one of fluorinated ethylene carbonate (F-EC), chloro-substituted ethylene carbonate (Cl-EC), fluorinated diethylene carbonate (F-DEC) and chloro-substituted diethylene carbonate (Cl-DEC), and R2=H, R3=CH2, R4=CH3 and R5=C2H4Z. In one embodiment, substance B is fluorinated ethylene carbonate (F-EC) and substance C is propenyl sulfite (PS).


In some embodiments, the solvent includes at least two members selected from the group consisting essentially of ethylene carbonate (EC), propylene carbonate (PC), diethylene carbonate (DEC) and γ-butyrolactone (GBL).


In one example, the solvent is a single chemical compound having the following properties: boiling point ≧120° C., flash point ≧25° C., electrochemical oxidation potential: Φox>3.0 V with respect to saturated calomel electrode (SCE), and electrochemical reduction potential: Φred<2.8 V (vs. SCE). In another example, the solvent includes a combination of EC, DEC and GBL, wherein the weight ratio of EC:DEC:GBL is about 2:2:1.


In one embodiment, the lithium salt includes at least one of lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium hexafluorophosphate (LiPF6). In one example, the lithium salt is LiPF6 having a concentration of from about 0.7 mol/L to about 1.3 mol/L.


One embodiment discloses a lithium secondary battery having a shell and a battery core disposed therein, and an electrolyte. In one embodiment, the battery core includes cathode, anode, a separator between the anode and the cathode, among other components. In some instances, the separator has the ability to insulate and maintain liquids within, the types of separator including without limitation polypropylene (PP), polyethylene (PE), polypolyolefin microporous membrane, polyethylene felt, fiberglass felt and ultra-fine fiberglass paper. In one example, the shell includes an anti-exploding indentation. In some embodiments, the electrolyte includes the electrolyte embodiments disclosed herein, among others. There are no limitations other parts and structures of the lithium secondary battery.


In one example, the cathode includes a cathode material, a conductive agent, and an adhesive. In some embodiments, the types of cathode material include without limitation at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide and lithium iron phosphate. In some embodiments, the types of conductive agent include without limitation at least one of carbon nano-tube, nano-silver powder, acetylene black, graphite powder and carbon black. In one embodiment, the amount of conductive agent can be from about 0.1% to about 10% of the cathode material by weight. In some embodiments, the types of adhesive include without limitation at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), hydroxymethyl cellulose (CMC), methylcellulose (MC) and styrene-butadiene rubber (SBR). In one embodiment, the amount of adhesive can be from about 0.1% to about 5% of the cathode material by weight.


In one example, the anode includes a conductive agent and an adhesive. In some embodiments, the types of conductive agent include without limitation at least one of carbon nano-tube, nano-silver powder, acetylene black, graphite powder and carbon black. In some embodiments, the types of adhesive include without limitation at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), hydroxymethyl cellulose (CMC), methylcellulose (MC) and styrene-butadiene rubber (SBR).


In some embodiments, the solvent for preparing the slurry for the cathode and the anode includes without limitation at least one of N-methyl pyrrolidone (NMP), dimethylformamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), water, alcohol and mixtures thereof. In one example, the amount of solvent to be used can be enough for coating the slurry onto the base and collector. In other examples, the amount of solvent can be from about 100% to about 150% by weight of the cathode or anode active materials.


One embodiment discloses a method of preparing a lithium-ion secondary battery including situating the separator between the cathode and the anode to form a battery core, which can be housed within a shell. The electrolyte can be injected within the shell and sealed to form the lithium-ion secondary battery. In one embodiment, a method of preparing the cathode includes mixing a slurry coating of cathode material, adhesive and conductive agent on a current collector, drying, pressing or rolling, and slicing to form the cathode. In some embodiments, the types of current collector include without limitation aluminum foil, copper foil and steel strip with nickel plating, among others. In one embodiment, a method of preparing the anode is substantially similar in all respect to that of preparing the cathode with the exception that conductive agents and adhesives for anodes are utilized.


The following examples provide additional details of the electrolyte embodiments of the present disclosure.


EXAMPLE 1

(1) Preparation of the Electrolyte


Prepare a mixture containing about 87.5 grams of EC, DEC and GBL at a weight ratio of about 2:2:1. Add about 12.5 grams of LiPF6 to the mixture. Mix an additive containing about 1.5 grams of VC, about 3 grams of F-EC and about 3.5 grams of PS to the mixture, process the mixture through granular molecular sieve (microporous pores) for absorbing water content. Allow the mixture to stand for about 24 hours and filter out the molecular sieve. In this electrolyte, the amount of VC is about 1.5% of the electrolyte by weight, the amount of F-EC is about 3% of the electrolyte by weight, and the amount of PS is about 3.5% of the electrolyte by weight.


(2) Preparation of the Cathode


Mix about 8.7 grams of NMP, about 1000 grams of acetylene black and about 300 grams of PVDF powder, stir for about 5 minutes to obtain a slurry. Add about 3 kilograms of NMP and about 5 kilograms of lithium cobalt oxide (Hunan Ruixiang New Materials Co., LTD, China) to about 2 kilograms of the slurry, and stir for about 200 minutes to obtain a cathode material. Coat the cathode material on an aluminum foil current collector, the thickness of the aluminum foil being about 20 microns. Dry, press and cut the aluminum foil to obtain a cathode plate having a dimension of about 360 mm by about 44 mm by about 0.15 mm. Apply about 5.4 grams to about 5.6 grams of the lithium cobalt cathode material on the cathode plate.


(3) Preparation of the Anode


Mix about 3 kilograms of natural graphite, about 90 grams of SBR, about 90 grams of CMC and about 3 kilograms of water, stir to obtain an anode slurry. Coat the anode slurry on a copper foil, the thickness of the copper foil being about 20 microns. Dry at about 120° C., press and cut the copper foil to obtain an anode plate having a dimension of about 410 mm by about 45 mm by about 0.18 mm. Apply about 2.7 grams to about 2.8 grams of the natural graphite anode material on the anode plate.


(4) Preparation of the Battery


Take the cathode and anode produced herein, together with a PP or PE separator film, and wind the cathode, anode and separator film to form a square-shaped lithium-ion battery core, which can be housed within a shell. The electrolyte (about 3 grams) produced herein may be injected into the shell and air-sealed to provide a lithium-ion battery. The lithium-ion battery produced is labeled A1.


In some embodiments, the lithium-ion battery may be an LP053450A or OEM compatible type battery. In other embodiments, the cathode, anode and separator film may be wounded and housed within a shell. The electrolyte may be injected into the shell and air-sealed to provide an ISO 9001, RoHS or CE certified lithium-ion battery, among other standards, certifications and compliances. In one embodiment, the design capacity of the battery has about 1 C equal to about 720 mAh. In another embodiment, the design capacity of the battery is about 3.7 V and about 750 mAh.


EXAMPLE 2

Substantially similar in all respect to that of EXAMPLE 1 except that the mixture additive in the electrolyte includes about 2 grams of VC, about 7 grams of F-EC and about 4 grams of PS. In this example, the amount of VC is about 2% of the electrolyte by weight, the amount of F-EC is about 7% of the electrolyte by weight, and the amount of PS is about 4% of the electrolyte by weight. The lithium-ion battery produced is labeled A2.


EXAMPLE 3

Substantially similar in all respect to that of EXAMPLE 1 except that the mixture additive in the electrolyte includes about 0.3 gram of VC, about 1.5 grams of F-EC and about 1.2 grams of PS. In this example, the amount of VC is about 0.3% of the electrolyte by weight, the amount of F-EC is about 1.5% of the electrolyte by weight, and the amount of PS is about 1.2% of the electrolyte by weight. The lithium-ion battery produced is labeled A3.


EXAMPLE 4

Substantially similar in all respect to that of EXAMPLE 1 except that the mixture additive in the electrolyte includes about 8 grams of VC, about 0.5 gram of F-EC and about 3 grams of 1,3-PS. In this example, the amount of VC is about 8% of the electrolyte by weight, the amount of F-EC is about 0.5% of the electrolyte by weight, and the amount of 1,3-PS is about 3% of the electrolyte by weight. The lithium-ion battery produced is labeled A4.


EXAMPLE 5

Substantially similar in all respect to that of EXAMPLE 1 except that the mixture additive in the electrolyte includes about 4 grams of VC, about 6 grams of F-EC and about 2 grams of PS. In this example, the amount of VC is about 4% of the electrolyte by weight, the amount of F-EC is about 6% of the electrolyte by weight, and the amount of PS is about 2% of the electrolyte by weight. The lithium-ion battery produced is labeled A5.


EXAMPLE 6

Substantially similar in all respect to that of EXAMPLE 1 except that the mixture additive in the electrolyte includes about 8 grams of VC, about 10 grams of F-EC and about 6 grams of 1,3-PS. In this example, the amount of VC is about 8% of the electrolyte by weight, the amount of F-EC is about 10% of the electrolyte by weight, and the amount of 1,3-PS is about 6% of the electrolyte by weight. The lithium-ion battery produced is labeled A6.


EXAMPLE 7

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 5 grams of VC, 3 grams of F-DEC and 10 grams of PS. In this example, the amount of VC is about 5% of the electrolyte by weight, the amount of F-DEC is about 3% of the electrolyte by weight, and the amount of PS is about 10% of the electrolyte by weight. The lithium-ion battery produced is labeled A7.


EXAMPLE 8

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 5 grams of VC, about 22 grams of F-EC and about 13 grams of 1,3-PS. In this example, the amount of VC is about 5% of the electrolyte by weight, the amount of F-EC is about 22% of the electrolyte by weight, and the amount of 1,3-PS is about 13% of the electrolyte by weight. The lithium-ion battery produced is labeled A8.


EXAMPLE 9

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 0.5 gram of VC, about 8 grams of F-EC and about 1.5 grams of ES. In this example, the amount of VC is about 0.5% of the electrolyte by weight, the amount of F-EC is about 8% of the electrolyte by weight, and the amount of ES is about 1.5% of the electrolyte by weight. The lithium-ion battery produced is labeled A9.


EXAMPLE 10

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 6 grams of VC, about 10 grams of F-DEC and about 5 grams of 1,3-PS. In this example, the amount of VC is about 6% of the electrolyte by weight, the amount of F-DEC is about 10% of the electrolyte by weight, and the amount of 1,3-PS is about 5% of the electrolyte by weight. The lithium-ion battery produced is labeled A10.


REFERENCE 1

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 3 grams of VC and about 2 grams of PS. In this reference sample, the amount of VC is about 3% of the electrolyte by weight and the amount of PS is about 2% of the electrolyte by weight. The lithium-ion battery produced is labeled B1.


REFERENCE 2

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 2 grams of VC and about 4 grams of F-DEC. In this reference sample, the amount of VC about is 2% of the electrolyte by weight and the amount of F-DEC is about 4% of the electrolyte by weight. The lithium-ion battery produced is labeled B2.


REFERENCE 3

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 3 grams of VC and about 4 grams of 1,3-PS. In this reference sample, the amount of VC is about 3% of the electrolyte by weight and the amount of 1,3-PS is about 4% of the electrolyte by weight. The lithium-ion battery produced is labeled B3.


REFERENCE 4

Substantially similar in all respect to that of Example 1 except that the mixture additive in the electrolyte includes about 3 grams of F-DEC and about 4 grams of 1,3-PS. In this reference sample, the amount of F-DEC is about 3% of the electrolyte by weight and the amount of 1,3-PS is about 4% of the electrolyte by weight. The lithium-ion battery produced is labeled B4.


The components and contents of the mixture additives (e.g., percentages of substances A, B and C) in the electrolytes of batteries A1-A10 (EXAMPLES 1-10) and batteries B1-B4 (REFERENCES 1-4) are summarized in Table 1.









TABLE 1







The components and contents of mixture additives in the electrolyte.












Total amount of
Substance A
Substance B
Substance C















additives
VC
F-EC
F-DEC
PS
1, 3-PS
ES


















EXAMPLE 1
8
1.5
3

3.5




EXAMPLE 2
13
2
7

4


EXAMPLE 3
3
0.3
1.5

1.2


EXAMPLE 4
11.5
8
0.5


3


EXAMPLE 5
12
4
6

2


EXAMPLE 6
24
8
10


6


EXAMPLE 7
18
5

3
10


EXAMPLE 8
40
5
22


13


EXAMPLE 9
10
0.5
8



1.5


EXAMPLE 10
21
6

10


5


REFERENCE 1

3


2


REFERENCE 2

2

4


REFERENCE 3

3



4


REFERENCE 4



3

4









Testing


1. Capacity Testing


At room temperature, batteries A1-A10 and B1-B4 are charged at 360 mA (0.5 C) to 4.2 V, charged at constant voltage of 4.2 V to cut-off current of 36 mA (0.05 C), and discharged at 360 mA to cut-off voltage of 3.0 V. The initial thicknesses and discharge capacities of the batteries are recorded in Table 2.









TABLE 2







Initial thicknesses and discharge capacities


at about 360 mA (0.5 C).












Thickness/mm
Capacity/mAh







A1
5.30
731



A2
5.30
730



A3
5.36
725



A4
5.36
723



A5
5.33
729



A6
5.48
710



A7
5.39
712



A8
5.53
706



A9
5.42
716



A10
5.41
708



B1
5.46
715



B2
5.36
715



B3
5.38
712



B4
5.39
710










2. High Temperature Storage Performance Testing


At room temperature, batteries A1-A10 and B1-B4 are charged at 360 mA (0.5 C) to 4.2 V, charged at constant voltage to cut-off current of 36 mA (0.05 C), and discharged at 360 mA (0.5 C) to cut-off voltage of 3.0 V. The initial thickness and initial capacity of each battery are noted. The batteries are maintained at about 85° C. in an oven for about 48 hours, removed, whereupon the thicknesses of the batteries are again noted. The change in thickness of each battery is recorded in Table 3.


The restoration capacity of each battery can be tested as follows: at room temperature, batteries A1-A10 and B1-B4 are charged at 360 mA (0.5 C) to 4.2 V, charged at constant voltage to cut-off current of 36 mA (0.05 C), and discharged at 360 mA (0.5 C) to cut-off voltage of 3.0 V. The charging/discharging steps are repeated three times whereby the third discharge capacity is the restoration capacity.


The calculations may be made using the following equations:

Capacity restoration rate(%)=(Restoration capacity/Initial capacity)×100%.
Changes in thickness (mm)=(Thickness after high temperature storage−Initial thickness)×100%.









TABLE 3







High temperature storage performance.












Capacity
Changes in




restoration rate (%)
thickness (mm)







A1
98%
0.09



A2
97%
0.10



A3
88%
0.30



A4
89%
0.18



A5
93%
0.14



A6
87%
0.32



A7
93%
0.16



A8
83%
0.40



A9
90%
0.12



A10
90%
0.28



B1
80%
0.67



B2
86%
0.45



B3
87%
0.43



B4
83%
0.46










Based on the results of Table 3, the capacity restoration rates of batteries A1-A10 (EXAMPLES 1-10) were generally at about 90%, with the highest being at about 98% (battery A1), while the capacity restoration rates of batteries B1-B4 (REFERENCES 1-4) varied from about 80 to 87%, indicating that batteries incorporating presently disclosed electrolyte embodiments are more rugged and better able to return to its initial state than reference samples. In addition, the change in thicknesses of batteries A1-A10 (generally about 0.2 mm) were also smaller than those of batteries B1-B4 (generally about 0.5 mm) indicating the ability of these batteries to withstand thermal treatment without compromising physical structure.


3. Safety Performance Testing


(a) Overcharging Performance


At room temperature, batteries A1-A10 and B1-B4 are overcharged at constant voltage and constant current to 12 V. The physical appearances of the batteries are recorded in Table 4.









TABLE 4







Overcharging performance.









State














A1
Inflated and Anti-Exploding Indentation Activated



A2
Inflated and Anti-Exploding Indentation Activated



A3
Inflated and Anti-Exploding Indentation Activated



A4
Inflated and Anti-Exploding Indentation Activated



A5
Inflated and Anti-Exploding Indentation Activated



A6
Inflated and Anti-Exploding Indentation Activated



A7
Inflated and Anti-Exploding Indentation Activated



A8
Inflated and Anti-Exploding Indentation Activated



A9
Inflated and Anti-Exploding Indentation Activated



A10
Inflated and Anti-Exploding Indentation Activated



B1
Exploded and burnt



B2
Exploded and burnt



B3
Exploded and burnt



B4
Exploded and burnt










(b) Boiler Thermal Performance


At room temperature, batteries A1-A10 and B1-B4 are charged at 360 mA (0.5 C) to 4.2 V, charged at constant voltage of 4.2 V to cut-off current of 36 mA (0.05 C), the voltage being maintained at about 4.20 V±0.02 V. The batteries are subsequently placed in an oven with the temperature of the oven rising from room temperature up to about 150° C. at heating rates of about 3-7° C./min. The batteries are maintained in the oven for 10 minutes at about 150° C. if no anomalies are observed. The physical appearances of the batteries are recorded in Table 5.









TABLE 5







Boiler thermal performance.









State














A1
Inflated and Anti-Exploding Indentation Activated



A2
Inflated and Anti-Exploding Indentation Activated



A3
Inflated and Anti-Exploding Indentation Activated



A4
Inflated and Anti-Exploding Indentation Activated



A5
Inflated and Anti-Exploding Indentation Activated



A6
Inflated and Anti-Exploding Indentation Activated



A7
Inflated and Anti-Exploding Indentation Activated



A8
Inflated and Anti-Exploding Indentation Activated



A9
Inflated and Anti-Exploding Indentation Activated



A10
Inflated and Anti-Exploding Indentation Activated



B1
Exploded and burnt



B2
Exploded and burnt



B3
Exploded and burnt



B4
Exploded and burnt










(c) Hotplate Thermal Performance


At room temperature, batteries A1-A10 and B1-B4 are charged at 360 mA (0.5 C) to 4.2 V, and charged at constant voltage of 4.2 V to cut-off current of 36 mA (0.05 C). The batteries are subsequently heated on a hot plate at about 250° C. The physical appearances of the batteries are recorded in Table 6.









TABLE 6







Hotplate thermal performance.









State














A1
Inflated and Anti-Exploding Indentation Activated



A2
Inflated and Anti-Exploding Indentation Activated



A3
Inflated and Anti-Exploding Indentation Activated



A4
Inflated and Anti-Exploding Indentation Activated



A5
Inflated and Anti-Exploding Indentation Activated



A6
Inflated and Anti-Exploding Indentation Activated



A7
Inflated and Anti-Exploding Indentation Activated



A8
Inflated and Anti-Exploding Indentation Activated



A9
Inflated and Anti-Exploding Indentation Activated



A10
Inflated and Anti-Exploding Indentation Activated



B1
Leaking and Exploded and burnt



B2
Exploded and burnt



B3
Exploded and burnt



B4
Exploded and burnt










Based on the results of Table 4-6, batteries A1-A10 exhibited better overcharge and thermal performances, while batteries B1-B4 generally exploded and burned. As such, the lithium secondary batteries containing the electrolyte embodiments of the present disclosure have better thermal performance and ruggedness, and are in general safer than reference samples.


Although the disclosure has been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit of the disclosure as described and defined in the following claims.

Claims
  • 1. An electrolyte comprising: a lithium salt;a solvent; andan additive, wherein the additive comprises substances A, B and C, wherein substance A is vinylene carbonate,wherein substance B has the chemical structure of at least one of
  • 2. The electrolyte of claim 1, wherein the solvent includes at least two members selected from the group consisting essentially of ethylene carbonate, propylene carbonate, diethylene carbonate and γ-butyrolactone.
  • 3. The electrolyte of claim 1, wherein the amount of additive can be from about 5% to about 40% of the electrolyte by weight.
  • 4. The electrolyte of claim 1, wherein substance B is at least one of fluorinated ethylene carbonate, chloro-substituted ethylene carbonate, fluorinated diethylene carbonate and chloro-substituted diethylene carbonate, and wherein R2=H, R3=CH2, R4=CH3 and R5=C2H4Z.
  • 5. The electrolyte of claim 1, substance B is fluorinated ethylene carbonate.
  • 6. The electrolyte of claim 1, wherein the lithium salt includes at least one of lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium hexafluorophosphate (LiPF6).
  • 7. A lithium battery comprising: a shell;a battery core disposed within the shell, wherein the battery core includes an anode, a cathode, and a separator disposed between the anode and the cathode; andan electrolyte, wherein the electrolyte comprises: a lithium salt;a solvent; andan additive, wherein the additive comprises substances A, B and C, wherein substance A is vinylene carbonate,wherein substance B has the chemical structure of at least one of
  • 8. The battery of claim 7, wherein the solvent includes at least two members selected from the group consisting essentially of ethylene carbonate, propylene carbonate, diethylene carbonate and γ-butyrolactone.
  • 9. The battery of claim 7, wherein the amount of additive can be from about 5% to about 40% of the electrolyte by weight.
  • 10. The battery of claim 7, wherein substance B is at least one of fluorinated ethylene carbonate, chloro-substituted ethylene carbonate, fluorinated diethylene carbonate and chloro-substituted diethylene carbonate, and wherein R2=H, R3=CH2, R4=CH3 and R5=C2H4Z.
  • 11. The battery of claim 7, substance B is fluorinated ethylene carbonate.
  • 12. The battery of claim 7, wherein the lithium salt includes at least one of lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium hexafluorophosphate (LiPF6).
  • 13. A method comprising: producing an electrolyte for lithium-ion batteries by mixing a lithium salt and an additive to a solvent, wherein the additive comprises substances A, B and C, wherein substance A is vinylene carbonate,wherein substance B has the chemical structure of at least one of
  • 14. The method of claim 13, wherein the solvent includes at least two members selected from the group consisting essentially of ethylene carbonate, propylene carbonate, diethylene carbonate and γ-butyrolactone.
  • 15. The method of claim 13, substance B is fluorinated ethylene carbonate.
  • 16. The method of claim 13, wherein the lithium salt includes at least one of lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium hexafluorophosphate (LiPF6).
  • 17. A method comprising: producing a lithium secondary battery by: situating a separator film between a cathode and an anode to form a battery core;disposing the battery core within a shell;injecting an electrolyte within the shell, wherein the electrolyte can be produced using the method of claim 15; andsealing the electrolyte and the battery core within the shell.
Priority Claims (1)
Number Date Country Kind
2008 1 0142212 Jul 2008 CN national
US Referenced Citations (49)
Number Name Date Kind
3778307 Beer et al. Dec 1973 A
4394280 von Alpen et al. Jul 1983 A
5910382 Goodenough et al. Jun 1999 A
6010806 Yokoyama et al. Jan 2000 A
6180800 Yokoyama et al. Jan 2001 B1
6514640 Armand et al. Feb 2003 B1
6558844 Howard, Jr. et al. May 2003 B2
6645452 Barker et al. Nov 2003 B1
6702961 Barket et al. Mar 2004 B2
6835500 Masquelier et al. Dec 2004 B2
6960331 Barket et al. Nov 2005 B2
6964830 Takahashi Nov 2005 B2
7025907 Kahzaki et al. Apr 2006 B2
7172834 Jow et al. Feb 2007 B1
7189475 Sasaki et al. Mar 2007 B2
7255965 Xu et al. Aug 2007 B2
7261979 Gozdz et al. Aug 2007 B2
7338734 Chian et al. Mar 2008 B2
7695863 Abe et al. Apr 2010 B2
7722848 Dai et al. May 2010 B2
20020047112 Hosoya et al. Apr 2002 A1
20020102459 Hosoya et al. Aug 2002 A1
20040151649 Hemmer et al. Aug 2004 A1
20060078801 Yamaguchi et al. Apr 2006 A1
20060083990 Adamson et al. Apr 2006 A1
20060228626 Kawashima et al. Oct 2006 A1
20060236528 Xu et al. Oct 2006 A1
20070160752 Mao Jul 2007 A1
20070166609 Lee et al. Jul 2007 A1
20070178370 Amine et al. Aug 2007 A1
20070184352 Donoue et al. Aug 2007 A1
20070207080 Yang Sep 2007 A1
20070212606 Chang Sep 2007 A1
20080286657 Hasegawa et al. Nov 2008 A1
20090081102 Dai Mar 2009 A1
20090106970 Fan Apr 2009 A1
20090142663 Takeuchi et al. Jun 2009 A1
20090148765 Cao et al. Jun 2009 A1
20090169984 Liang et al. Jul 2009 A1
20090191455 Gao et al. Jul 2009 A1
20090217512 Tian et al. Sep 2009 A1
20090217513 Xi et al. Sep 2009 A1
20090220856 Tian et al. Sep 2009 A1
20090220858 Cheng Sep 2009 A1
20090220860 Xi et al. Sep 2009 A1
20090302283 Xia et al. Dec 2009 A1
20100059706 Dai et al. Mar 2010 A1
20100062339 Pan et al. Mar 2010 A1
20100167121 Arai et al. Jul 2010 A1
Foreign Referenced Citations (38)
Number Date Country
1259773 Jul 2000 CN
1401559 Mar 2003 CN
1410349 Apr 2003 CN
1424980 Jun 2003 CN
1559889 Jan 2005 CN
1641912 Jul 2005 CN
1648036 Aug 2005 CN
1677718 Oct 2005 CN
1762798 Apr 2006 CN
1773754 May 2006 CN
1775665 May 2006 CN
1797823 Jul 2006 CN
1925206 Mar 2007 CN
1964125 May 2007 CN
1986395 Jun 2007 CN
1989649 Jun 2007 CN
101047268 Oct 2007 CN
101087021 Dec 2007 CN
101106189 Jan 2008 CN
101128950 Feb 2008 CN
101207197 Jun 2008 CN
101209827 Jul 2008 CN
101212048 Jul 2008 CN
101399343 Apr 2009 CN
101420048 Apr 2009 CN
101453019 Jun 2009 CN
101471432 Jul 2009 CN
101478041 Jul 2009 CN
101478042 Jul 2009 CN
101494305 Jul 2009 CN
1146586 Oct 2001 EP
1553647 Jul 2005 EP
1855334 Nov 2007 EP
9740541 Oct 1997 WO
2005076936 Aug 2005 WO
2006066470 Jun 2006 WO
2006112674 Oct 2006 WO
2008109734 Sep 2008 WO
Non-Patent Literature Citations (38)
Entry
Related U.S. Appl. No. 12/035,978, entitled “Lithium Iron Phosphate Cathode Material,” Final Office Action (mailed Dec. 7, 2009).
USPTO Transaction History of related U.S. Appl. No. 12/035,978, filed Feb. 22, 2008, entitled “Lithium Iron Phosphate Cathode Material.”
USPTO Transaction History of related U.S. Appl. No. 12/040,773, filed Feb. 29, 2008, entitled “Composite Compound with Mixed Crystalline Structure.”
USPTO Transaction History of related U.S. Appl. No. 12/053,308, filed Mar. 21, 2008, entitled “Cathode Materials for Lithium Batteries.”
USPTO Transaction History of related U.S. Appl. No. 12/127,431, filed May 27, 2008, entitled “Lithium Iron Phosphate Cathode Material.”
USPTO Transaction History of related U.S. Appl. No. 12/198,087, filed Aug. 25, 2008, entitled “Lithium-Ion Rechargeable Battery Preparation.”
USPTO Transaction History of related U.S. Appl. No. 12/254,537, filed Oct. 20, 2008, entitled “Lithium Iron(II) Phosphate Cathode Active Material.”
USPTO Composite Transaction History of related U.S. Appl. No. 12/273,649, filed Nov. 19, 2008, entitled “Composite Separator Films for Lithium-Ion Batteries.”
USPTO Transaction History of related U.S. Appl. No. 12/316,165, filed Dec. 9, 2008, entitled “Composite Compound with Mixed Crystalline Structure.”
USPTO Transaction History of related U.S. Appl. No. 12/316,173, filed Dec. 9, 2008, entitled “Composite Compound with Mixed Crystalline Structure.”
USPTO Transaction History of related U.S. Appl. No. 12/316,180, filed Dec. 9, 2008, entitled “Composite Compound with Mixed Crystalline Structure.”
USPTO Transaction History of related U.S. Appl. No. 12/316,234, filed Dec. 9, 2008, entitled “Composite Compound with Mixed Crystalline Structure.”
USPTO Transaction History of related U.S. Appl. No. 12/352,981, filed Jan. 13, 2009, entitled “Electrolyte for Batteries and Battery Packs.”
USPTO Transaction History of related U.S. Appl. No. 12/436,347, filed May 6, 2009, entitled “Transition Metal Hydroxide and Oxide, Method of Producing the Same, and Cathode Material Containing the Same.”
European Search Report for EP09400001 (mailed Apr. 14, 2009).
Hu, Huan-yu et al., “Influenece of the Mg-substitution on electrochemical performances of LiFePO4,” China Academic Journal Electronic Publishing House, pp. 18-20, vol. 30, No. 1, 2006.
International Patent Application Serial No. PCT/CN08/70391, International Search Report and Written Opinion (mailed Jul. 17, 2008).
Pei, Su-hua et al., “Sensitivity of TiO2 : NB2O5 composite crystalliod to trimethylamine”, Journal of Functional Materials and Devices, vol. 12, No. 3, Jun. 2006.
Related U.S. Appl. No. 12/035,978, entitled “Lithium Iron Phosphate Cathode Material ,” Non-Final Office Action (mailed Apr. 27, 2009).
Related U.S. Appl. No. 12/035,978, entitled “Lithium Iron Phosphate Cathode Material ,” Non-Final Office Action (mailed Oct. 2, 2008).
Related U.S. Appl. No. 12/035,978, entitled “Lithium Iron Phosphate Cathode Material,” Final Office Action (mailed Jan. 9, 2009).
Related U.S. Appl. No. 12/127,431, entitled “Lithium Iron-Phosphate Cathode Material,” Final Office Action (mailed Jun. 26, 2009).
Related U.S. Appl. No. 12/127,431, entitled “Lithium Iron-Phosphate Cathode Material,” Non-Final Office Action (mailed Jan. 30, 2009).
Yun et al., “Synthesis and electrochemcial properties of olivine-type LiFe PO4/C composite cathode material prepared from a poly(vinyl alcohol)-containg precursor.” Journal of Power Sources vol. 160, issue 2, Oct. 2006, pp. 1361-1368 (Available online May 9, 2006).
Related U.S. Appl. No. 12/127,431, entitled “Lithium Iron-Phosphate Cathode Material,” Non-Final Office Action (mailed Oct. 20, 2009).
Patent Cooperation Treaty; PCT International Search Report; Sep. 17, 2009; 4 pages; China.
Abstract Translation of WO2007043624; Apr. 19, 2007; 1 page.
Abstract Translation of JP2007194037; 1 page; Japan.
Abstract Translation of JP2006294519; 1 page; Japan.
Abstract Translation of JP2006004649; 1 page; Japan.
Abstract Translation of JP2004158213; Jun. 3, 2004; 1 page; Japan.
Abstract Translation of CN101394007; 1 page; China.
Abstract Translation of CN101213703; 1 page; China.
Abstract Translation of CN101138125; 1 page; China.
Abstract Translation of CN101093901; 1 page; China.
Abstract Translation of CN101093900; 1 page; China.
Abstract Translation of CN1925206; 1 page; China.
Abstract Translation of CN1161036; 1 page; China.
Related Publications (1)
Number Date Country
20100028771 A1 Feb 2010 US