Batteries for Implantable Biomedical Devices

Batteries for Implantable Biomedical Devices Edited by Boone B. Owens Boone B. Owens, Inc. St. Paul, Minnesota

PLENUM PRESS • NEW YORK AND LONDON

Library of Congress Cataloging in Publication Data

Batteries for implantable biomedical devices.

Bibliography: p. Includes index. 1. Implants, Artificial-Power supply. 2. Electric batteries. I. Owens, Boone B.

RD132.B37 1986 617'.95 86-582

ISBN 978-1-4684-9047-3 ISBN 978-1-4684-9045-9 (eBook)

DOl 10.1007/978-1-4684-9045-9

© 1986 Plenum Press, New York

Softcover reprint of the hardcover 1 st edition 1986

A Division of Plenum Publishing Corporation 233 Spring Street, New York, N. Y. 10013

All rights reserved

No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise without written permission from the Publisher

Contributors

BAROUH V. BERKOVITS • New England Research Center, Wellesley, Mas-sachusetts 02181

MICHAEL BILITCH • USC Pacemaker Center, Los Angeles, California 90033

KENNETH R. BRENNEN. Medtronic, Inc., Minneapolis, Minnesota 55440

MICHAEL BROUSSElY • Departement Generateurs de Technologies Avan-cees, SAFf, Poitiers 86000, France

KEITH FESTER. Medtronic, Inc., Minneapolis, Minnesota 55440

JEAN-PAUL GABANO • Departement Generateurs de Technologies Avan­cees, SAFf, Poitiers 86000, France

MICHAEL GRIMM. Departement Generateurs de Technologies Avancees, SAFf, Poitiers 86000, France

GERHARD L. HOllECK • Battery Division, EIC Laboratories, Inc., Nor­wood, Massachusetts 02062

CURTIS F. HOLMES. Research and Development, Wilson Greatbatch Lim­ited, Clarence, New York 10431

JOHN S. KIM. Medtronic, Inc., Minneapolis, Minnesota 55440

SAMUEL C. lEVY. Sandia National Laboratories, Albuquerque, New Mex­ico 87185

BOONE B. OWENS. Departement Chemical Engineering and Materials Science, University of Minnesota Minneapolis, Minnesota 55455

DAVID L. PURDY. Coratomic.Inorana Pennsylvania 15701-0434

vi CONTRIBUTORS

SAMUEL RUBEN • Reed College, Portland, Oregon 97202

ALVIN J. SALKIND • Department of Surgery, Bioengineering Section, UMDNJ-Rutgers Medical School, Piscataway, New Jersey 08854

PAUL M. SKARSTAD • Medtronic, Inc., Minneapolis, Minnesota 55440

ALAN J. SPOTNITZ. Department of Surgery, Thoracic Section, UMDNJ-Rutgers Medical School, Piscataway, New Jersey 08854

KENNETH B. STOKES • Medtronic, Inc., Minneapolis, Minnesota 55440

DARREL UNTEREKER • Medtronic, Inc., Minneapolis, Minnesota 55440

Foreword

Small sealed electrochemical power units have developed remarkably in the last two decades owing to improvements in technology and a greater understanding of the underlying basic sciences. These high-energy-density sealed battery sys­tems have made possible the safe and rapid development of lightweight implant­able electrical devices, some of which, such as heart pacers, have reached a large market. In most of these devices the battery constitutes the majority of the device volume and weight, and limits the useful life.

This book on Batteries for Implantable Biomedical Devices will be highly welcome to those interested in devices for heart pacing, pain suppression, bone repair, bone fusion, heart assist, and diabetes control, as well as numerous other biomedical devices that depend on sealed batteries. However, the material will also be extremely useful to a much broader audience, including those concerned with sealed batteries for such other difficult environments as space, the sea and remote locations.

The material included in this book is very comprehensive and contains both discussions of the excellent basic science and inside "know-how" on design and assembly operations. Dr. Boone Owens has selected scientists of worldwide reknown as chapter authors. Both he and the authors are active in research on and development and production of power sources and medical devices, and they have made significant contributions to the field. The first major implantable electrical devices (heart pacers) were based on mercury batteries, which were the invention of Dr. Samuel Ruben. It was a great pleasure for me to review this development with Dr. Ruben. The inventors and developers of the current advanced lithium batteries-as well as the co-inventor of the heart pacer, Dr. Greatbatch-have also contributed chapters of great educational and reference value.

vII

viii FOREWORD

I believe this book fills a unique niche in its coverage. It contains discussions of physiology, biological energy requirements, material science, electrochem­istry, and battery technology treated in a cohesive manner. It will be helpful for power source researchers, medical students and physicians, and evaluators of present and future generations of implantable power sources and devices.

Alvin J. Salkind Professor and Chief Surgery/Bioengineering UMDNJ-Rutgers Medical School and Visiting Professor Chemical and Biochemical Engineering Rutgers University

Preface

One may speculate whether nearly 200 years ago as Volta constructed his famous Pile, he considered the future roles that would be played by portable stores of electricity. In our present society the battery serves consumers in many diverse ways-portable tools, radios, televisions, recorders, flashlights, wrist watches, emergency lights, smoke detectors, vehicle starting, portable telephones, pagers, hearing aids, telephone memory elements, utility metering, and the list continues on and on. The size of batteries varies over a surprising ten orders of magnitude, from ten milliwatt-hour memory cells to 100 Megawatt-hour batteries planned for utility load leveling. The electrochemical battery, always a component of some larger system and never the end item itself, best meets the user's needs when the user is not even aware of this collection of reactive chemicals that are contained in a manner ready to instantly convert chemical energy into electrical energy.

Military needs and space exploration prompted much of the first research and development to improve on the standard batteries which had been in use for decades. For example, the space suits of astronauts now contain highly advanced, lightweight lithium cells to power television lights and cameras as well as their communication units. Space exploration also has applications for rechargeable batteries to serve as ultra-reliable power sources, capable of operating over ten years and for many thousands of cycles under conditions that do not permit battery maintenance or replacement.

Another field driving recent battery development has been medicine. Many applications for implanted medical devices require batteries. These bat­teries power appliances to sustain life, alleviate pain, facilitate healing, dis­pense drugs, and complement other body functions. This area of application is unique in its combination of environmental, electrical, and reliability require­ments.

Ix

x PREFACE

The most well-known implantable medical device is the cardiac pacemaker. Mercury-zinc cells initially represented the best available combination of energy and reliability for the pacemaker of the 1960s. By the end of the sixties, it was clear pacemaker longevity was limited by the battery and further longevity im­provement (necessary to reduce the need for device-replacement surgery) would depend upon power source improvements.

The decade of the 1970s saw the convergence of integrated circuit tech­nology with the technology of small, hermetically-sealed high-energy-density lithium batteries as well as nuclear power sources. Reliability and longevity improvements paralleled reduction in device size and simplification of the med­ical procedures for using cardiac pacemaker therapy. The first commercial ap­plication of a lithium battery occurred in Veronna, Italy in 1972, when a lith­ium-iodine battery-powered pacemaker was implanted.

During the seventies, several new and diverse types of lithium battery systems were developed for this application. Both successes and failures were recorded, but as the 1980s have evolved, a maturing of lithium primary cell technology is in progress. Low-rate batteries for pacemakers have demonstrated highly reliable, real-time performance out to ten years. However, new therapies appear to require higher power levels in order to treat conditions such as tach­yarrythmias, fibrillation, pain and scoliosis; and the artificial heart and implant­able ventricular assist devices would benefit from a reliable hermetic, secondary battery that would be stable at 37°C and be of smaller volume and mass than presently available batteries of equivalent energy content. At this time, many laboratories are working on rechargeable high-energy-density lithium batteries, and medical batteries of this type should become available during the next decade. Thus the need for improved batteries continues and ongoing developmental efforts will satisfy these new requirements in the future.

The purpose of the present technical monograph is to summarize the tech­nologies of batteries that have been developed and applied to implantable medical devices. This assessment is performed at a time corresponding to about ten years following the implementation of the various lithium primary batteries into pace­makers.

This book is the result of the efforts of many contributors. The editor wishes to thank all of the authors for their participation in this endeavor. The encour­agement of the management at Medtronic is also gratefully acknowledged; Peter Mulier was especially instrumental in my early interest in implantable medical devices.

The able clerical assistance of Roxanne Olson, Linda Thomas, and Joanne Yates are all gratefully acknowledged. Special thanks must go to Diane Doyle who very reasonably and capably coordinated the frequent communications be-

PREFACE xl

tween the authors, the editor, and the publisher, and brought together the myriad of details that were required to bring order to the final manuscript.

Finally, the help of my wife, Tinie, who steadily encouraged my efforts, is acknowledged with sincere appreciation.

Boone B. Owens St. Paul, Minnesota

Contents

1. Electrically Driven Implantable Prostheses

ALVIN J. SALKIND, ALAN J. SPOTNITZ, BAROUH V. BERKOVITS,

BOONE B. OWENS, KENNETH B. STOKES, AND MICHAEL BIUTCH

1. General Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 1.1. Physiology, Medical Significance, and History .......... 1 1.2. Electronic Circuit Technology. . . . . . . . . . . . . . . . . . . . . . .. 5

2. Devices Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 2.1. Heart Pacing Systems .............................. 7 2.2. Cardiac Pacing Leads .............................. 14 2.3. Automatic Implantable Defibrillator ................... 21 2.4. Bone Growth and Repair ............................ 22 2.5. Other Devices ..................................... 26

3. Business Aspects ...................................... 31 4. Future Directions ...................................... 32

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33

2. Key Events in the Evolution of Implantable Pacemaker Batteries

BOONE B. OWENS AND ALVIN J. SALKIND

1. Introduction........................................... 37 2. An Interview with Samuel Ruben ......................... 38 3. An Interview with Wilson Greatbatch ...................... 44

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49

xIII

xlv CONTENTS

3. Lithium Primary Cells for Power Sources

DARREL UNTEREKER

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51 2. The Elements of a Battery ............................... 53

2.1. Anode ........................................... 54 2.2. Cathode.......................................... 55 2.3. Electrolyte/Separator ............................... 55 2.4. Feedthrough ...................................... 58

3. Battery Parameters ..................................... 60 4. Battery Performance .................................... 62 5. Microcalorimetry ...................................... 68 6. Implantable Battery Chemistries .......................... 72

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 81

4. Evaluation Methods

KEITH FESTER AND SAMUEL C. LEVY

1. Evaluation Objectives .......... . . . . . . . . . . . . . . . . . . . . . . . .. 83 1.1. Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 83 1.2. Reliability Data ................................... 84 1. 3. Quality Assurance ................................. 85

2. Accelerated Testing .................................... 85 2.1. Empirical Approach ................................ 87 2.2. Statistical Approach ................................ 87 2.3. Physicochemical Approach .......................... 88 2.4. Accelerated Testing without Failure ................... 91 2.5. Designing an Accelerated Life Test ................... 93 2.6. Other Acceleration Methods ......................... 93

3. Nonaccelerated Testing ................................. 96 3.1. Real-Time Tests ................................... 96 3.2. Materials Testing .................................. 97 3.3. Microcalorimetry .................................. 98

4. Qualification Protocol . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. 99 4.1 Sample Qualification Plan . . . . . . . . . . . . . . . . . . . . . . . . . . .. 99

5. Data Analysis ........................................ 101 5.1. Longevity Projections ............................. 102 5.2. Statistical Evaluation of Battery Longevity ............ 103 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 109

CONTENTS

5. Battery Performance Modeling

KENNETH R. BRENNEN AND JOHN S. KIM

xv

1. Description of the Problem ............................. 113 2. Importance of the Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 114 3. Description of the Variables and Relationships ............. 114 4. Classification of Models ................................ 117 5. Statistical Methods .................................... 117

5.1. Self-Discharge ................................... 118 5.2. Polarization ...................................... 120

6. Modeling of the Lithium/Iodine Pacemaker Battery. . . . . . . . .. 120 7. Device Longevity ..................................... 126

7.1. Pulse Generator Hardware ....................... . .. 126 8. Conclusion .......................................... 130

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 130

6. Lithium/Halogen Batteries

CURTIS F. HOLMES

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 133 2. General Features of LithiumlHalogen Solid Electrolyte Batteries 134

2.1. Thermodynamic Considerations ..................... 134 2.2. Kinetic Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 135

3. The LithiumIBromine System ........................... 136 3.1. General Considerations ............................ 136 3.2. The LilBr2-PVP Cell ............. . . . . . . . . . . . . . . . .. 138 3.3. Other Cathode Formulations ........................ 138 3.4. Summary ....................................... 138

4. Chemistry of the LithiumlIodine-Polyvinylpyridine System ... 139 4.1. Cell Reaction .................................... 139 4.2. The Lithium Anode ............................... 140 4.3. The Cathode Material ............................. 141 4.4. The Electrolyte/Separator .......................... 146

5. Construction of LithiumlIodine-PVP Cells. . . . . . . . . . . . . . . .. 151 5.1. Principles of Cell Design . . . . . . . . . . . . . . . . . . . . . . . . . .. 151 5.2. The Central Anode/Case-Neutral Design .............. 153 5.3. The Central Cathode/Case-Neutral Design ............. 154 5.4. The Central Anode/Case-Grounded Design ............ 155 5.5. Central Anode/Case-Grounded Pelletized Cathode Cells .. 156

xvi CONTENTS

6. Discharge Characteristics of the Lillz-PVP Battery .......... 157 6.1. General Considerations ............................ 157 6.2. Discharge Characteristics at Application Current Drain .. 158 6.3. The Effect of Current Drain on Cell Perfonnance ....... 164 6.4. Self-Discharge ................................... 165 6.5. Modeling and Accelerated Testing ................... 167

7. Perfonnance of the Lillz-PVP Cell ....................... 171 7. 1. General Remarks ................................. 171 7.2. The Approach to Cell Reliability .................... 171 7.3. Perfonnance of Life Test Batteries ................... 172 7.4. Perfonnance of the LilI2-PVP Cell

in Cardiac Pacemakers ............................ , 173 8. Summary and Conclusion .............................. 175

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 177

7. Lithium Solid Cathode Batteries for Biomedical Implantable Applications

JEAN-PAUL GABANO, MICHAEL BROUSSELY, AND MICHAEL GRIMM

1. Introduction.......................................... 181 2. General Features of Lithium Solid Cathode Systems ......... 182

2.1. Thennodynamic Considerations ..................... 182 2.2. Some Properties of Electrodes and Electrolytes ......... 182 2.3. Electrode and Cell Configurations ................... 186

3. Specific Systems Used for Biomedical Applications ......... 186 3.1. The Lithium-Silver Chromate Organic

Electrolyte System ................................ 187 3.2. The Lithium-Cupric Sulfide Organic Electrolyte Battery ... 196 3.3. The Lithium-Vanadium Pentoxide Organic

Electrolyte System ................................ 199 3.4. The Lithium-Manganese Dioxide Cell ................ 203 3.5. Solid Electrolyte Lithium Cells ...................... 204

4. Use of Lithium Solid Cathode Systems in Implanted Medical Devices ...................................... 208 4.1. Lithium-Silver Chromate .......................... 209 4.2. Lithium-Cupric Sulfide ............................ 210 4.3. Lithium-Vanadium Pentoxide ....................... 210 4.4. Lithium-Manganese Dioxide ....................... 211 4.5. Lithium-Lead Iodide, Lead Sulfide .................. 211

5. Summary and Conclusions .............................. 211 References ......................................... '. 212

CONTENTS

8. Lithium-Liquid Oxidant Batteries

PAUL M. SKARSTAD

xvII

1. Introduction.......................................... 215 2. Description of the System .............................. 217

2.1. Liquid Oxidant Systems ........................... 217 2.2. Cell Reaction .................................... 218 2.3. Principles of Operation ............................ 219

3. Capacity and Energy Density ............................ 220 3.1. Classification of Losses ............................ 220 3.2. Stoichiometric Energy and Capacity Density ........... 221 3.3. Capacity Density of Practical Electrodes .............. 224 3.4. Packaging Efficiency .............................. 228 3.5. Electrochemical Efficiency ......................... 230

4. State-of-Discharge Indication ............................ 248 5. Voltage Delay ........................................ 250

5.1. Anode Passivation ................................ 250 5.2. Alleviation of Voltage Delay ....................... 251

6. Safety .............................................. 252 6.1. Short Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 252 6.2. Overdischarge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 253 6.3. Charging ........................................ 255 6.4. Casual Storage ................................... 255 6.5. Disposal ........................................ 256 6.6. Future.......................................... 256 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 257

9. Mercury Batteries for Pacemakers and Other Implantable Devices

AL YIN J. SALKIND AND SAMUEL RUBEN

1. Background .......................................... 261 2. Chemistry ........................................... 262 3. Cell Design and Performance Characteristics ............... 266

References ........................................... 274

10. Rechargeable Electrochemical Cells as Implantable Power Sources

GERHARD L. HOLLECK

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 275 2. Nickel Oxide/Cadmium Cells ........................... 276

xviii CONTENTS

2.1. Brief History .................................... 276 2.2. General Nickel Oxide/Cadmium Cell Characteristics .... 276 2.3. The Nickel Oxide/Cadmium Pacemaker Cell ........... 278

3. Rechargeable Mercuric Oxide/Zinc Cells .................. 279 3. 1. Brief History .................................... 279 3.2. Cell Chemistry and Construction .................... 280 3.3. Cell Performance ................................. 281

4. Prospects for Future Use of Rechargeable Cells ............. 282 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 283

11. Nuclear Batteries for Implantable Applications

DAVID L. PuRDY

1. General Description of Nuclear Batteries ................. 285 1.1. Description ofIsotopic Decay .................... " 285 1.2. Types of Nuclear Batteries ........................ 287

2. Isotope Selection ..................................... 288 2.1. General Parameters .............................. 288 2.2. Isotope Longevity ............................... 288 2.3. Isotope Comparisons ............................. 290

3. Detailed Characteristics of the Plutonium-238 Isotope ....... 292 3.1. Fuel Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 292 3.2. Types of Radiation ............................... 294 3.3. Helium Release ................................. 296

4. Thermoelectric Generator Systems ...................... 297 4.1. Nuclear Battery Subsystems ....................... 297 4.2. Biosphere Protection ............................. 299 4.3. Operating Environment Design Requirements ......... 300

5. Thermopile Design ................................... 302 5. 1. Seebeck Effect .................................. 302 5.2. Thermal and Electrical Performance ................. 302 5.3. Material Characteristics ........................... 305 5.4. Design Optimization ............................. 307

6. Insulation Design and Selection ......................... 308 7. Fuel Capsule Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 311

7.1. General Description .............................. 311 7.2. Helium Pressure ................................. 311 7.3. Capsule Material ................................ 312 7.4. Capsule Geometry ............................... 312 7.5. Capsule Stress Analysis ........................... 313 7.6. Credible Accident Testing ......................... 322

8. Thermal Analysis .................................... 328 9. Electrical Characteristics .............................. 336

CONTENTS x~

10. Radiation Effects .................................... 337 10.1. Somatic Effects ................................ 337 10.2. Genetic Effects ................................. 339 10.3. Public Exposure ................................ 342

11. Licensing Requirements ............................... 342 12. Applications of Nuclear Batteries ....................... 343 13. Nuclear Battery Reliability ............................. 349

References ........................................ " 350

Index ............................................................ 353

Batteries for Implantable Biomedical Devices