Linden D., Reddy T.B. (eds.) Handbook of batteries

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RECHARGEABLE LITHIUM BATTERIES (AMBIENT TEMPERATURE) 34.31

Lithium/ Niobium Selenide (Li/ NbSe

) Batteries. This cathode material is attractive be-

cause it can accept (intercalate) three lithium ions per molecule. The cathode can also be

made without any binder and conducting diluent because of its soft, ﬁbrous nature and high

electronic conductivity. A AA-size cylindrical battery can deliver about 1.1 Ah with an

average voltage of 2.0 V. Figure 34.18 shows the discharge characteristics of a Li/NbSe

battery at various discharge rates and temperatures.

The battery has a mildly canted dis-

charge proﬁle. An important characteristic of this system is its high-rate discharge capability

(up to the 2C rate). A typical discharge and charge cycle is shown in Fig. 34.18c. More than

200 cycles were obtained at 75% depth of discharge.

The development of this system was terminated despite its technical promise.

FIGURE 34.18 Discharge characteristics of the Li / NbSe

AA-size battery. (a) Discharge curves

at 20⬚C (mA). (b) Discharge curves at different temperatures (⬚C) at 200 mA. (c) Typical discharge

and charge curve for the Li/ NbSe

AA-size battery. Discharge: 400 mA; charge: 80 mA.

34.32 CHAPTER THIRTY-FOUR

Lithium/ Lithiated Cobalt Dioxide (Lu/ Li

CoO

) and Lithium/ Lithiated Nickel Dioxide

(Li/Li

NiO

) Batteries. These batteries are characterized by a high cell voltage, high en-

ergy density, good low-temperature performance, relatively high charge-discharge rates, and

moderate cycle life. The net charge and discharge reactions of the Li /Li

CoO

cell can be

represented by the cell reaction:

discharge

⫹

—— —



xLi ⫹ L CoO LiCoO

———

⫺

x 2



charge

The Li /Li

CoO

battery is manufactured in a fully discharged state and thus requires a charge

prior to its usage. When used in combination with oxidation-resistant ester-based solvents

(methyl formate or methyl acetate), the battery can reach full charge at 4.2 to 4.3 V de-

pending on the cycle history of the cell.

A Li/Li

CoO

battery that utilizes an ester-based electrolyte displays a ﬂat discharge at

3.85 to 3.95 V in a cathode compositional range of between x

⫽ 0.5 and x ⫽ 1.0, depending

on the discharge rate conditions.

Batteries have been built in cylindrical spirally wound conﬁgurations in AA (300 to 600

mAh), D (4–6 Ah), and larger sizes. The electrolyte consists of LiAsF

/LiBF

in methyl

formate, methyl acetate, or a mixture of both. Figure 34.19a shows the discharge character-

istics of a 5-Ah D-size battery. The effect of various charging procedures on the discharge

performance is illustrated in Fig. 34.19b for a 30-Ah battery. Figure 34.19c shows the cycle

life characteristics of a D-size battery. The battery also has good storage capability. The

effects of storage on both initial capacity after storage and permanent capacity loss are

summarized in Table 34.14. Capacity losses of batteries stored at temperatures up to 35

⬚C

in the charged state can be fully recovered on the ﬁrst charge.

The charge and discharge reactions of the Li/ Li

NiO

battery are similar to those of the

lithiated cobalt oxide system:

discharge

⫹

—— —



xLi ⫹ Li NiO LiNiO

———

⫺

x 2



charge

Batteries have been build in a spirally wound cylindrical D size. Table 34.15 lists the design

parameters. This D-cell battery employed an alloy anode of 85% Li-15% Al. Figure 34.20a

shows the discharge characteristics of the battery at several discharge rates and Fig. 34.20b

shows the cycle life characteristics. The declining capacity of the cell with cycling is attrib-

uted to increasing impedance of the cathode.

While there is currently no commercial production, the Li /Li

CoO

and Li/Ni

CoO

sys-

tems continue to receive attention for military applications because of their high speciﬁc

energy and energy density.

RECHARGEABLE LITHIUM BATTERIES (AMBIENT TEMPERATURE) 34.33

FIGURE 34.19 (a) Discharge characteristics of a 5-Ah Li /Li

CoO

D-

size battery at 20⬚C. (Delivered speciﬁc energy at 1.0 A, 70 Wh/ lb.) (b)

Effect of charging rates on discharge performance of 30-Ah Li / Li

CoO

battery at 20⬚C. - - -, constant potential at 4.20 V [current limit at 5.0

mA/cm

(C / 2)]. ——, constant current at 1.0 mA / cm

(C / 10). Discharge

rate at C /6. (c) Cycle life characteristics of a Li/ Li

CoO

D-size battery.

Charge at 300 mA, 4.3 V. Discharge at 3 A, 3.0 V. (From Alliant Tech-

systems.).

34.34 CHAPTER THIRTY-FOUR

TABLE 34.14 Effect of Storage at 20⬚C on Capacity Retention of Charged Li/ Li

CoO

D-Size Batteries

Charge and

prestorage

test conditions

Average

capacity

of ﬁrst

5 cycles, Ah

Discharge

capacity

after 15-day

(360-h)

storage, Ah

Capacity

loss

during

storage

period, %

Average

capacity of

next 5

cycles

after storage,

Permanent

capacity

loss due to

storage, %

4.3 V charge 5.1 4.6 9.8 5.2 0

(0.5 F / M)

4.1 V charge 4.05 3.65 9.9 4.0 1

(0.4 F / M)

4.1 V ﬂoat charging 4.05 4.2 0 4.0 1

TABLE 34.15 Design Features of Li/ LiNiO

D-Size Batteries

Positive electrode (supported on aluminum grid):

89.5% LiNiO

, 2% graphite, 5% EC600 carbon,

0.015 in (0.38 mm)

Porosity 40%

Loading 75 mg /cm

Negative electrode (four copper wires running length of electrode):

15% Al-85% Li

0.004 in (0.10 mm)

Electrode capacity ratio:

Li anode

⫽ 3

LiNiO cathode

Electrolyte:

1.2M LiAsF

in PC /EC /DMC

18 ml

Separator:

Celgard 2400 (1 ply)

Polyethylene (2 ply)

General:

Working area 900 cm

Allowance for expansion 5%

Nickel-plated steel hardware

Molybdenum pin and TA-23 glass-to-metal seal

RECHARGEABLE LITHIUM BATTERIES (AMBIENT TEMPERATURE) 34.35

FIGURE 34.20 (a) Discharge characteristics of a Li / Li

NiO

D-size battery. Charge at 0.3 A

to 4.1 V. (b) Cycle life characteristics of a Li/ Li

NiO

D-size battery. Discharge at 2 A to 2.8 V.

Charge at 0.4 A to 4.1 V. Taper to 0.1 mA. (From Ref. 42.)

34.36 CHAPTER THIRTY-FOUR

34.4.2 Polymer Electrolyte Cells

The polymer electrolyte lithium batteries contain all solid-state components: lithium as the

anode material, a thin polymer ﬁlm as a solid electrolyte and separator, and a transition metal

chalcogenide or oxide, or a sulfur-based polymer as the cathode material. These features

offer the potential for improved safety because of the reduced activity of lithium with the

solid electrolyte, ﬂexibility in design as the cell can be fabricated in various sizes and shapes,

and high energy density.

Figure 34.9 shows a schematic cross section of a solid polymer electrolyte cell. The

cathode and electrolyte are coated onto a current collector to form a thin sheet, called the

cathode laminate. The lithium metal foil is applied to the cathode laminate to form a layered

structure, with the solid polymer separating the lithium from the cathode. These cells are

designed in extremely thin components with high surface areas to minimize the internal

resistance and compensate for the lower conductivity of the polymer electrolyte. The thick-

ness depends on the speciﬁc cell design and required capacity. A thicker laminate delivers

a higher capacity per unit area of electrode, but with lower efﬁciency at the higher current

drains.

The early batteries used polyethylene oxide (PEO)-based electrolytes containing a lithium

salt, which have an appreciable conductivity at about 100

⬚C but low conductivity at room

temperature. Later new polymeric electrolyte materials, such as PEO copolymers, PEO

blends, plasticized PEO electrolytes, and gelled electrolytes, with better conductivity were

developed. Some of the cathode materials investigated for these batteries are TiS

,VO

,Li

CoO

and sulfur-based polymers.

The solid polymer electrolyte (SPE) battery has been considered for a wide range of

applications, from small portable electronics up to and including electric vehicles.

34.4.3 Lithium Batteries Using PEO-based Electrolytes

In the late 1970s, polymer electrolyte materials were proposed for use in solid-state battery

designs.

A considerable development effort has resulted in a number of review arti-

cles

45–47

describing the status of such batteries in some detail. The unique aspect of these

batteries is that the electrolyte is a solid ﬂexible ﬁlm comprised of a polymer matrix and an

ionic salt complexed into the matrix. Thin-ﬁlm solid-polymer electrolyte batteries offer the

possibility of an intrinsically safe battery design in combination with good high-rate capa-

bility.

Polyethylene oxide was the ﬁrst material utilized as the matrix material. Initially, it was

necessary to operate the cells at elevated temperatures (100

⬚C) to obtain adequate conduc-

tivities (10

⫺

S/ cm), but a variety of polymeric electrolytes that may be useful at normal

ambient temperatures were subsequently developed. This polymer electrolyte battery is based

on thin-ﬁlm components that incorporate large area electrolyte and electrode layers. A gen-

eral cell can be schematized as:

⫹

Li 具A典/Li ion-conductor /Li 具B典

where Li

具A典 is a metallic lithium anode or a low-voltage lithium-intercalation anode (neg-

ative electrode), the Li

⫹

ion conductor is a lithium salt-polymer complex, and Li

具B典 is a

high-voltage lithium-intercalation cathode (positive electrode). Usually, the polymer com-

ponent of the electrolyte layer is also the binder for the electrode layers. In addition, the

RECHARGEABLE LITHIUM BATTERIES (AMBIENT TEMPERATURE) 34.37

polymer component may be gelled by the addition of low molecular weight (liquid) solvents

to enhance its ionic conductivity. Such a battery system shows two major advantages with

respect to standard batteries that use inert porous separators:

1. The electrode and electrolyte layers are laminated (usually by heating and pressing the

layers), thus allowing various battery shapes without loss of contact.

2. Even if a low molecular weight (liquid) plasticizer is added to obtain high conductivity

at ambient and sub-ambient temperatures, there is no free liquid present in the battery

thus preventing any leakage problems.

Examples of the battery systems under development or available on the marketplace are

indicated in Table 34.16. They can be conveniently classiﬁed into three categories:

1. Positive and negative intercalation electrodes (lithium-ion) with a gelled polymer electro-

lyte (PEO-based).

2. Positive and negative intercalation electrodes (lithium-ion) with a porous polymer sepa-

rator layer ﬁlled with a liquid electrolyte (PVDF-based).

3. Positive intercalation electrode-lithium anode (lithium-metal) with a dry polymer electro-

lyte layer.

The ﬁrst and the second categories, the latter of which (PVDF-based systems) does not

properly belong to the class of polymer electrolyte batteries, are covered in Chap. 35. In this

chapter, the attention is focused on the lithium metal, dry polymer electrolyte systems.

The search for high energy density batteries, especially for electric vehicle applications,

has led to the consideration of the use of lithium metal anodes. No other anode can attain

the same electrochemical performance in terms of speciﬁc energy as metallic lithium. How-

ever, safety issues as well as poor cycle life performance have prevented the commercial

success of lithium-metal batteries with the exception of primary batteries. At the present

time, there are three major programs aimed at the development of lithium-anode, dry-polymer

electrolyte batteries for electric vehicles (Table 34.17). Within these R&D programs, sub-

stantial successes have been obtained in terms of cyclability of the lithium-polymer electro-

lyte interface

as well as the whole battery system.

However, Argotech’s battery NPS-

24V80 (Table 34.18) appears to be the only system close to commercialization. This battery,

designed for telecommunication applications (especially for outside plants), is a fall-out of

the EV battery module developed within the USABC program.

Figure 34.21 illustrates the internal design of the lithium polymer cell. The cell is made

by laminating ﬁve thin layers including an insulating layer, a lithium foil anode, a solid

polymeric electrolyte, a transition metal oxide cathode (VO

) and a current collector. The

unit cell is made by winding the laminated ﬁlm into a jelly roll (as in Fig. 34.21) or a ﬂat

roll (preferred for multiple cell battery assembly) structure. These cells are then assembled

in series and in parallel arrangements to form modules of different sizes and shapes for

numerous applications. As an example, Fig. 34.22 illustrates the design of a lithium-polymer

battery module for electric vehicle applications. Unit laminated cells are packaged into a

stack of ﬂat cells to create a module. The cells can be connected in parallel and /or series

arrays within a single container to build the desired module capacity and voltage. The pack-

aging also provides the mechanical, electrical, and thermal controls required for operation.

Each module is a fully functional battery system, including intelligent control and monitoring

electronics that interface with the battery pack controller.

34.38

TABLE 34.16 Status of Lithium and Lithium-Ion Polymer Battery Development (

from Ref. 48;

from Ref. 49)

Manufacturer Country Cathode Anode Electrolyte

Voltage

Energy Specific

density energy

Wh/ L Wh / kg Application

Matsushita Battery

Japan LiCoO

Graphite PVDF gel 3.7 250/ 125 Cellular

Sony

Japan LiCoO

Graphite PVDF gel 3.7 245/ 125 Cellular, PC

Japan Storage

Battery

Japan LiCoO

Graphite PVDF gel 3.6 210/ 125 Cellular, MiniDisc

Hitachi Maxell

Japan LiCoO

Graphite PEO gel 3.6 130 / 90 Cellular, PC

Sanyo

Japan LiCoO

Graphite PEO gel? 3.6 200/ 120 Cellular

Toshiba

Japan LiCoO

Graphite PVDF gel 3.6 245/ 115 Cellular, PC

Yuasa Corp.

Japan LiCoO

Coke PEO gel 3.6 165 / 95 Cellular, MiniDisc

Hirion/ Mitsubishi

Chem.

Japan LiCoO

Graphite PEO gel 3.7 280 / 130 Cellular, PC

Ultralife

US LiMn

Graphite PVDF gel 3.7 185/ 105 Cellular, PC

Valence

US LiMn

Graphite PVDF gel 3.7 220/ 110 PC

Thomas & Betts

(HET)

US LiCoO

Graphite PVDF gel 3.7 220/ 120 Cellular

Lithium

Technology

US LiCoO

Graphite PVDF gel 3.6 240/ 125 PC

ElectroFuel

Canada LiCoO

Graphite PVDF gel 3.6 435/ 175 PC

Argotech

(HydroQuebec/ 3M)

Canada VO

Li-metal Dry PEO 24 (2.6) 110 / 97 Telecommunications

facilities

Shubila

Malaysia LiCoO

Graphite PVDF gel 3.6 215/ 120 Cellular

RECHARGEABLE LITHIUM BATTERIES (AMBIENT TEMPERATURE) 34.39

TABLE 34.17 Major Lithium Metal Anode, Dry Polymer Electrolyte (PEO-based), Battery

Technology Development Projects (from Ref. 50)

Sponsor Project leaders Cathode Application Status

USABC (USA) IREQ-3M-ANL VO

EV 2.4 kWh

prototypes

Bollore´ Tech.

EDF (France)

CEREM VO

,Li

MnO

EV Prototypes

MICA-MURST

(Italy)

ENEA VO

,Li

MnO

EV Scaling-up to

1 kWh

prototypes

TABLE 34.18 Speciﬁcations of Argo-Tech’s Batteries from Ref. 49

NPS-24V80 EV module

Nominal voltage

24 V /Module

2.65 V /Cell

20 V

Rated capacity 80 Ah (@ C /8) 119 Ah (@ C / 3)

Rated energy 1.9 kWh (@ C /8) 2.4 kWh @ C / 3)

Maximum discharge current 20 A 365 A

Float voltage

27.9 V /Module

3.1 V /Cell

N/A

Energy density 110 WhL

⫺

220 WhL

⫺

Speciﬁc energy 97 Whkg

⫺

155 Whkg

⫺

Length 394 mm Application speciﬁc

Width 176 mm Application speciﬁc

Height 251 mm Application speciﬁc

Volume 17.4 dm

ca.11dm

Weight 19.9 kg 15.7 kg

Ambient operating temperature

⫺40 to 65⬚C N/A

Storage temperature

⫺40 to 65⬚C N/A

Float life at 40

⬚C Over 10 years N /A

Cycle life at 60

⬚C (80%

DOD)

200 cycles 600 cycles

FIGURE 34.21 Laminated lithium-polymer electrolyte cell assembly. (From the Proceedings of EVS 16,

reprinted by permission of the publisher, EVAAP.)

34.40 CHAPTER THIRTY-FOUR

FIGURE 34.22 Design of a Lithium Polymer Battery (LPB) module for EV applications. The module

includes an enclosure which provides mechanical support and thermal insulation along with control hardware

and vehicle interfaces. (From the Proceedings of EVS 16, reprinted by permission of the publisher, EVAAP.)

The speciﬁcation given for the stationary application NPS-24V80 battery are given in

Table 34.18 and compared with the parent EV-module. A typical discharge curve is depicted

in Figure 34.23. The battery is able to deliver 80 Ah capacity at a 10 A discharge rate in a

⬚C temperature environment. The excellent performance at high ambient temperature is

one of the major advantages of this system. The unit cells operate at 40 to 60

⬚C, and do not

contain any liquid: The battery is designed to have no degradation in non-ventilated and

warm environments (for example: telecommunication centers). It contains no liquid, thus it

is hermetically sealed, and dry-out during operation and liquid leakage are impossible, and

therefore no maintenance is required. In addition, the battery shows very good safety char-

acteristics. Overcharging tests showed no gas generation.

Once more, no liquid leakage is

possible even when the module is accidentally crushed. Finally and most important, water

immersion tests on entire crushed cells showed only a very slow reaction.