Lithium Batteries for Implantable Biomedical
Devices – Chemistry and Applications
Presented at Indiana University
March 23, 2010
Curtis F. Holmes, PhD.
Greatbatch, Incorporated
Greatbatch, Incorporated
The company was founded in 1970 by Mr. Wilson Greatbatch,
an electrical engineer and the co-inventor of the cardiac
pacemaker,
Mr. Greatbatch believed in 1970 that the remaining
problem to be solved for the pacemaker was the battery.
He licensed the lithium/iodine technology, hired
experienced battery scientists, and marketed the
lithium/iodine battery to the pacemaker industry.
By 1977, virtually all pacemakers were powered by
lithium batteries.
The company has grown through acquisition and market growth.
Sales in 2006 were > $270 million. There are ~2200 employees
at present. There are facilities in Western New York, Mexico,
Minneapolis, Pennsylvania, Switzerland, and China.
2
Critical Component Supplier
Batteries
Capacitors
Enclosures
Feedthroughs
Engineered Components
EMI Filters
Value Add Assembly
Coated Electrodes
Commercial Batteries
3
What is a battery (electrochemical cell)?
“Battery” means a device consisting of one or more
electrically connected electrochemical cells which is
designed to receive, store, and deliver electric energy.
An electrochemical cell is a self-contained system
consisting of an anode, cathode, and an electrolyte,
plus such connections (electrical and mechanical) as
may be needed to allow the cell to deliver or receive
electrical energy.
- Federal Government Definition
4
Basic Cell
5
The Baghdad Battery
A 2,200-year-old clay
jar found near
Baghdad, Iraq in
1936, has been
described as the
oldest known electric
battery in existence.
The clay jar and
others like it have
been attributed to
the Parthian Empire
— an ancient Asian
culture that ruled
most of the Middle
East from 247 B.C. to
A.D. 228. It is thought
that the “battery”
was used to
electroplate jewelry
objects with gold
The nondescript earthen
jar is only 5½ inches high
by 3 inches across. The
opening was sealed with
an asphalt plug, which
held in place a copper
sheet, rolled into a
tube. This tube was
capped at the bottom
with a copper disc held
in place by more asphalt.
A narrow iron rod was
stuck through the upper
asphalt plug and hung
down into the center of
the copper tube — not
touching any part of it.
6
The Voltaic pile
In 1799, Alessandro Volta (1745 –
1827) arranged a vertical pile of metal
discs (zinc with copper or silver) and
separated them from each other with
paperboard discs that had been
soaked in saline solution. This stack
became known as the voltaic pile and
was the progenitor for modern
batteries. The French word for
battery is “la pile.”
7
Cell Chemistry and Thermodynamics
• Cell Voltage
– Cathode materials and anode materials have different
electrochemical potentials, determined by thermodynamics
– The cell open circuit voltage (OCV) represents the difference
of cathode and anode electrochemical potentials. The OCV
of the battery is determined by the Gibbs Free Energy of the
battery reaction, according the following equation:
G = -nF Eº = H - T  S
where G is the Gibbs Free Energy, n is the number of
moles transferred in the cell reaction, F is the Faraday
Constant (96,500 coul/mole), and Eº is the OCV.
∆S = (nF) ∂ Eº
∂T
8
Cell Chemistry and Thermodynamics
• Important Battery Properties
t
– Capacity (Ampere hours) = ∫0 Idt
– Energy (Watt hours) = ∫0 E.Idt
– Power (Watts) = E.I
t
where I is current, E is voltage, and t is time.
9
Implantable Battery Applications
• Pacemaker
• Neurostimulator
• Drug Delivery
• Implantable Cardiac Defibrillator
• Implantable Hearing Devices
• Left Ventricular Assist Device/Totally Artificial Heart
10
Types of Lithium Implantable Medical
Batteries
•
•
•
•
•
Lithium/Iodine
Lithium/CFx
Lithium/Silver Vanadium Oxide (SVO)
Lithium/Manganese Dioxide
Q Technologies
High Rate – QHR
Medium Rate QMR
• Lithium/Hybrid (CFx and SVO Mixture)
• Lithium Ion Rechargeable
11
Types of Lithium Implantable Medical
Batteries
• Two Battery Systems will be
discussed in detail in this
presentation – the Lithium/Iodine
pacemaker battery and the
Lithium/Silver Vanadium Oxide
Defibrillator Battery.
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What does a pacemaker cure?
•
We all have a pacemaker! - The heart's "natural" pacemaker is called the
sinoatrial (SA) node or sinus node. It's a small mass of specialized cells in the top
of the heart's right atrium (upper chamber). It generates the electrical impulses
that cause the heart to beat.
•
The natural pacemaker may be defective (Stokes-Adams syndrome), causing the
heartbeat to be too fast, too slow or irregular. The heart's electrical pathways also
may be blocked. A patient with a heart beat of less than 60 BPM is said to have
“bradycardia.” A heart rhythm that is too slow can cause fatigue, dizziness,
lightheadedness, fainting or near-fainting spells.
•
Patients suffering from bradycardia need an artificial pacemaker to supply the
same electrical impulses that the sinoatrial node provides in healthy people.
•
Over 900,000 pacemakers per year are implanted worldwide.
•
The first successful cardiac pacemaker, invented by Mr. Wilson Greatbatch and
Dr. William Chardack, was implanted into a patient at the Veterans’ Hospital in
Buffalo in 1960.
13
Early 1960’s - Ten Batteries, two transistors!
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Modern Pacemaker – one battery, thousands of
“transistors”
15
Batteries for Pacemakers
• The lithium/iodine battery was developed and patented by scientists at
Catalyst Research Corporation in the early 1970’s. Their invention was
based on work done at the Jet Propulsion Laboratory in the late 1960’s
and published in the Journal of the Electrochemical Society. Mr. Wilson
Greatbatch licensed the fundamental patents from CRC and, with battery
scientists Ralph Mead and Frank Rudolph, invented and patented many
improvements (e. g., anode coating and the case-grounded design).
• The first lithium/iodine cell was implanted in Italy in April 1972. Before
that time, pacemakers were powered by zinc/mercuric oxide batteries that
were short-lived, unreliable, unpredictable, and discharged hydrogen gas.
• Since that time, millions of cells have been implanted.
• Most pacemakers currently being implanted use lithium/iodine cells,
although some advanced pacemakers are using Li/CFx, lithium hybrid
cathode batteries, and QMR cells.
16
Batteries for Pacemakers
•
April 2010 will mark the 38th anniversary of the first implant of a
pacemaker powered by a Li/Iodine battery. The implant occurred in
Italy.
•
Since that time, millions of cells have been implanted.
•
Although several lithium-based chemical systems have seen use in
pacemakers (silver chromate, cupric sulfide, thionyl chloride,
manganese dioxide, titanium disulfide), the lithium/iodine battery
became the only remaining pacemaker battery technology until the
introduction of liquid electrolyte batteries such as Li/CFx and the
“hybrid” battery (mixed CFx and silver vanadium oxide) in the last
few years. It remains the most widely-used pacemaker battery
today.
•
The battery has compiled a remarkable record of reliability and
predictable performance.
•
It is arguably the first successful commercialization of a lithiumanode battery.
•
It will continue to be used for the foreseeable future.
The Lithium/Iodine battery
•
One could argue that, based on standard battery performance
criteria, it’s not a very good battery!
•
•
•
•
•
•
•
It can’t start a car, run a cell phone, or even power a
flashlight.
It has very high internal resistance
It doesn’t work well when it’s cold.
It doesn’t work well when it’s too hot (above 55⁰C).
Temperatures above 60⁰C will permanently damage the
cell. It explodes like a bomb at 180.5ºC (the melting point
of lithium).
It’s not inexpensive to manufacture.
BUT – Put it at 37⁰C and ask it to provide 10 – 50
microamperes of current, and it will do it reliably for many
years.
The Lithium/Iodine Battery
•
It has been said that it is a very “elegant” battery
system
•
•
•
Elegant in its simplicity

Simple cell reaction

Straightforward cell design
Elegant in its complexity

Very complicated interactions among iodine, PVP,
and lithium

Performance shows a very strong dependence on cell
discharge current
Elegant in its performance record

Remarkable record of reliability and usefulness for 35
years.
Lithium/Iodine Battery
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Lithium Anode
Atomic Number: 3
Atomic Mass: 6.941 amu
Melting Point: 180.54 °C
Boiling Point: 1347.0 °C
Number of Protons/Electrons: 3
Number of Neutrons: 4
Classification: Alkali Metal
Crystal Structure: Cubic
Density @ 293 K: 0.53 g/cm3
Color: silvery
Ionization Potential: 5.39 eV
Electrochemical Equivalent: 3.86 Ah/Gram
Trivia Note: Lithium metal is one of only two
materials that react with elemental nitrogen at
room temperature (if humidity is present)!
21
Anode Coating
• In the early 1970’s it was discovered by Greatbatch scientists that
coating the anode with PVP dissolved in a volatile solvent greatly
affected the performance of the cell. The coating was done with a
camel’s-hair paint brush. The PVP was dissolved in
tetrahydrofuran and painted onto the anode. The THF was dried,
and the PVP remained on the anode. This improvement was
patented in 1976 (patent Number 3,957,533)
• The coating has a profound positive effect on the discharge
characteristics of the cell.
• Studies at Medtronic in the 1980’s showed that the coating led to
the formation of a yellow liquid exhibiting ionic conductivity during
discharge, contributing to the observed improvement in cell
performance.
• In 1987 a substrate coating method was developed. It is a much
more efficient way of coating the anode and results in much more
uniform coating weights and cell performance.
22
Comparison of discharge curves of
uncoated and coated anode cells
23
Lithium Iodide Electrolyte/Separator
•
•
•
•
•
•
•
Ionic Salt
Density = 3.494 gr/cm3
Lithium Ion Conductivity = 10-7 S/cm
Negligible Electronic Conductivity
Negligible Iodide ion conductivity
Self-forming, Self-healing
Structure greatly modified by coating the anode
with PVP
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The Iodine/Polyvinylpyridine (PVP) cathode
material
The Iodine/PVP material is formed by a thermal reaction
between iodine and PVP. The reaction occurs above the
melting point of iodine (~113⁰C). This thermal reaction is
exothermic and produces a tar-like material that melts slightly
below the melting point of iodine. At the 30/1 weight ratio used
at Greatbatch, the material is mostly elemental iodine at unit
thermodynamic activity, with a small amount of the reaction
product of iodine with PVP:
25
DSC of Formation of the Cathode Material
26
Phase Diagram of the Iodine/PVP Material –
dotted line is 37° C
As the cell is discharged, the
cathode material transitions
from region 6 through region 5,
and finally to region 4.
Region 6 is a 2-phase system
containing the eutectic melt
and pure iodine.
Region 5 is a single phase
liquid material.
Region 4 is a two-phase
system wherein the one-to-one
iodine/monomer unit adduct
phase coexists with the melt.
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Conductivity of the Iodine/PVP cathode material
The conductivity of the iodine/PVP material has been
shown to be electronic in nature.
Electron Paramagnetic Resonance spectroscopy of
the cathode material shows a single narrow signal with
a g value of 2.002. This indicates that there exist free
(unpaired) electrons in the material.
The conductivity is a function of the ratio of iodine to
PVP in the material, as shown in the next slide.
28
Conductivity of the Iodine/PVP cathode material
29
Thermodynamic Characteristics of the
Lithium/Iodine Reaction (300º K)
Li + ½ I2 → LiI
∆G = ∆H - T∆S
From JANAF Thermochemical Tables:
∆G = -64.451 kcal/mole
∆H = -64.551 kcal/mole
T∆S = -0.101 kcal/mole
∆G = ∆H - T∆S = -nF Eº
Eº = 2.8 volts
∆S = (nF) ∂ Eº
∂T
30
Lithium/ Iodine Cell Reaction
31
Discharge curves of a typical Li/Iodine
battery at various constant resistive loads
32
What does an implantable
defibrillator/cardioverter (ICD) cure?
• Ventricular tachycardia - a potentially lethal disruption of normal
heartbeat that may cause the heart to become unable to pump
adequate blood through the body. The heart rate may be 160 to
240 (normal is 60 to 100 beats per minute). Uncontrolled, it can
lead to ventricular fibrillation.
• Ventricular fibrillation - a condition in which the heart's electrical
activity becomes totally disordered. When this happens, the
heart's lower (pumping) chambers contract in a rapid,
unsynchronized way. (The ventricles "flutter" rather than beat.)
The heart pumps little or no blood. The outcome of this
condition, absent appropriate therapy, is both obvious and grim.
33
History of the ICD
•
The ICD was invented by Dr. Michel Mirowski at the Johns Hopkins
University in 1979.
•
The first ICD’s were simple “shock boxes” that detected VF and
provided the high-energy shock directly to the heart to stop the VF and
restore normal sinus rhythm. They were also big – around 210 cm3.
•
These devices used a patch electrode that was sutured onto the heart.
This meant that a thoracotomy (cracking the chest) had to be
performed, and about 5% of the patients died from this major surgery.
Today a transvenous lead is used, greatly reducing the trauma and the
time required for the implantation.
•
A technique called “tiered therapy” was developed in the late 1980’s.
This technique detected tachycardia and attempted to pace the patient
back to normal rhythm with lower-energy pacing. It provided the highenergy shock only if it failed to restore normal rhythm by pacing. Today
almost all ICD’s provide tiered therapy. The smallest ICD today is under
30 cm3.
34
ICD - 1989
This unit was
larger than 120
cm3. It required
a patch
electrode that
had to be
sutured directly
to the heart, a
very traumatic
and difficult
surgical
procedure.
35
ICD – 2010
The Ovatio ICD is
produced by Sorin
Group, a European
company with locations
in France and Italy. With
a volume of 29 cm3, it is
the smallest ICD
currently on the market.
The unit is connected to
the heart with a
transvenous lead,
greatly reducing the
trauma of implant
surgery.
36
Batteries for Implantable Cardiac Defibrillators – The
lithium/silver vanadium oxide battery
•
Scientists at Greatbatch, Inc. developed the lithium/silver vanadium
oxide (Li/SVO) battery system in 1982. It was adapted for use in the
implantable defibrillator a few years later.
•
In 1987 the first ICD powered by Li/SVO was implanted in Sydney,
Australia.
•
Li/SVO has become the technology standard and most ICDs use the
system.
•
SVO has the ability to deliver high power
•
It has high volumetric energy density
37
Lithium/Silver Vanadium Oxide Battery
38
Silver Vanadium Oxide (SVO)
• Silver Vanadium oxide (Ag2V4O11) belongs to a class of chemical
compounds of somewhat indeterminate stoichiometry called
“Vanadium Oxide Bronzes.”
• They were first synthesized and studied by Casalot, Pouchard,
and coworkers at the Centre national de la recherche
scientifique in France. They were interested in the compound’s
rather interesting magnetic properties.
• SVO can be synthesized via several different reactions. The
reaction used at our company is the thermal decomposition of
Vanadium Pentoxide and Silver Nitrate:
2V2O5 + 2AgNO3
→
Ag2V4O11 + 2NO2 + 1/2O2
• The compound exists in several phases depending on the
conditions of synthesis.
39
Silver Vanadium Oxide Structure
40
SEM Image of Silver Vanadium Oxide
41
Li/SVO Battery Characteristics
•
•
•
•
•
•
•
•
Cell Reaction:
High Voltage:
High Capacity:
High Power:
DOD Indication:
Long Shelf Life:
Safety and Reliability:
Issues Studied:
Ag2V4O11 + 7 Li → Li7Ag2V4O11
3.2V
1.37 Ah/cm3
20-30 mA/cm2
Staged Disch. Profile
Self Disch.<2%/Year
Extensively Tested
Rdc Growth/V-Delay
42
Defibrillator Battery 3-year discharge
curve
43
Discharge Curve/Cell Reaction –
“first plateau”
44
“Q” Technology – a brief introduction
• A new cell system has been developed that provides
high energy density, high power and high stability
• A suitable battery technology for next generation ICDs
• Proven technology with patent protection and with 5
years real time cell test data
• Flexible and scaleable cell design to meet the market
needs
• Mechanistically based performance Model developed to
predict battery performance under various applications
45
Q Technology – Combining the Carbon
Monofluoride and SVO Chemistries
46
Summary
• Over five million people have been implanted with
battery-powered devices.
• Devices treat heart problems, pain, epilepsy, chronic
illnesses, hearing loss, and other human illnesses.
• These devices are powered by lithium batteries, which
offer high energy density, reliability, and longevity.
• Significant improvements in battery performance,
electronic circuitry, and electrodes have permitted
newer, smaller devices that perform a wide variety of
functions.
47