Patent for Sale:

Battery Management System - Principle and Optimization Method    

Battery management system circuit and principle allowing balancing of individual cells in a series string by electrically removing them from the string without physically disconnecting them.


A novel way of balancing [usually lithium] battery cells that applies to any gadget or machinery using battery as portable power source, such as electric or hybrid vehicles, stand-by or uninterruptable power supplies, power tools, and such. The method allows very desirable benefit of electrically removing individual cells out of series string being charged without physically removing these cells from (switching in and out of) the string. This allows effectively disconnecting completely charged cells while allowing other cells to keep charging at the same rate, thus achieving ideal balance of state of charge (SOC) of all cells. Equal SOC of all cells is necessary for safety, peak performance and longest possible life of a battery pack consisted of multiple cells (or multiple groups of paralleled cells) connected in series strings.

Primary Application of the Technology

Electric vehicles, hybrid vehicles, electric boats, electric aircraft, stand-by power supplies, UPS, portable battery power, back-up power supplies, power tools, portable medical equipment, military electronic equipment, consumer electronics, electrified toys, etc. Pretty much any gadgets, machinery or equipment that completely or partially partially runs on rechargeable battery power or requires battery as portable power source will benefit from improvement of battery management system proposed in the patent.

The Problem Solved by the Technology

Achieving lithium cells balancing in very short time, low cost and high efficiency for any battery capacity, all at the same time - combination not available using present methods.

How the Technology Solves the Problem

Each battery cell can be evaluated and charge completed individually, which prevents any cell from harmful and dangerous overcharge. The problem is solved by electrically removing completely full cells from the series string of cells still being charged. The method also allows to discharge individual cells while keep charging other cells if desired. This is done by special arrangement of individual DC/DC converters which are generic and independent of the control circuit.

Competitive Advantage

As active balancing technology, it is energy efficient. It does not use proprietary components or components sourced by a single company, cheap (high performance/price ratio), scalable to any capacity of the battery without sacrificing efficiency, can be integrated into (or designed as add-on to) the front end of an existing battery management system, so customers can retain proprietary software algorithms or battery management strategies.

Frequently Asked Questions

Q. How is this method different from other active balancing methods available on the market?

A. Unlike existing methods, proposed method does not transfer charge to/from individual cell from/to either adjacent cell or a small section of entire string of cells thus potentially unbalancing them. It just removes (stops charging) cells which are done charging while allowing other cells to keep charging, so the method does not unbalance remaining string or its individual cells.

Patent Summary

U.S. Patent Classes & Classifications Covered in this listing:

Class 320: Electricity: Battery Or Capacitor Charging Or Discharging

Method or apparatus for controlled or regulated charging, discharging, or combined charging and discharging of one or more voltaic cells, batteries, or capacitors. Charging or electrically rejuvenating (e.g., depolarizing, etc.) a voltaic cell, battery, or electrical capacitor, wherein said charging or rejuvenating is accomplished by controlled addition of electrical energy into the cell, battery, or capacitor. Discharging - a voltaic cell, battery, or electrical capacitor, wherein discharging is accomplished by controlled release of electrical. A cell, battery, or capacitor structurally combined with a generator or electrical converter, whether or not electrical interconnection therebetween is recited.

Subclass 118: With discharge of cells or batteries
Subclass 119: With individual charging of plural batteries or cells
Subclass 120: Having variable number of cells or batteries in series