# US 10,374,443 B2 · Method and system for charging multi-cell lithium-based battery packs

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- Number: US 10,374,443 B2
- Document ID: US10374443B2
- Status: Granted
- Kind: B2
- Application number: 16/017,788
- Filed: 2018-06-25
- Published: 2018-10-25
- Granted: 2019-08-06
- Earliest claimed: 2002-11-22
- Assignees: Milwaukee Electric Tool Corporation
- Applicants: Milwaukee Electric Tool Corporation
- Inventors: Gary D. Meyer; Jay J. Rosenbecker; Kevin L. Glasgow; Todd W. Johnson; Karl F. Scheucher
- Web page: https://patentgrep.com/patent/US10374443B2

## CPC

- H02J 7/485: {with provisions for charging different types of batteries}
- H02J 7/04: Regulation of charging current or voltage
- H02J 7/44: between battery management systems and power sources
- H02J 7/443: {using passive battery identification means, e.g. resistors or capacitors (identification by mechanical connections H02J7/751)}
- H02J 7/50: acting upon multiple batteries simultaneously or sequentially
- H02J 7/52: for charge balancing, e.g. equalisation of charge between batteries
- H02J 7/56: Active balancing, e.g. using capacitor-based, inductor-based or DC-DC converters
- H02J 7/61: against overcharge
- H02J 7/63: against overdischarge
- H02J 7/65: against overtemperature
- H02J 7/663: {using battery or load disconnect circuits (H02J9/002 takes precedence)}
- H02J 7/685: {using connection detecting circuits (H02J7/68 takes precedence)}
- H02J 7/70: characterised by the mechanical construction
- H02J 7/751: {concerning the insertion or the connection of the batteries}
- H02J 7/82: Control of state of charge [SOC]
- H02J 7/875: {Charging or discharging for charge maintenance, battery initiation or rejuvenation}
- H02J 7/92: with prioritisation of loads or sources
- H02J 7/927: {with introduction of pulses during the charging process}
- H02J 7/96: in response to battery voltage
- H02J 7/977: {of the battery}
- H01M 10/4257: {Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries}
- Y02E 60/10: Energy storage using batteries
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method and system for charging multi-cell lithium-based batteries. In some aspects, a battery charger includes a housing, at least one terminal to electrically connect to a battery pack supported by the housing, and a controller operable to provide a charging current to the battery pack through the at least one terminal. The battery pack includes a plurality of lithium-based battery cells, with each battery cell of the plurality of battery cells having an individual state of charge. The controller is operable to control the charging current being supplied to the battery pack at least in part based on the individual state of charge of at least one battery cell.

## Claims

### Claim 1

An electrical combination comprising:
a battery charger including a housing;
at least one terminal to electrically connect to a battery pack supported by the housing, the battery pack including a plurality of lithium-based battery cells, each battery cell of the plurality of battery cells having an individual state of charge; and
a controller operable to control the battery charger to supply a charging current to the battery pack through the at least one terminal, the controller being operable to control the charging current being supplied to the battery pack based at least in part on the individual state of charge of at least one battery cell, the controller being further operable to control the battery charger to supply the charging current to the battery pack by controlling the battery charger to supply the charging current in a plurality of pulses of charging current, the plurality of pulses each having a first period of time, in which the charging current is being supplied to the battery pack at a predefined amplitude, and a second period of time, in which the supply of charging current is suspended, the controller being operable to control the charging current being supplied to the battery pack by modifying the first period of time and controlling the second period of time to be constant.

### Claim 2 (depends on 1)

The electrical combination as set forth in claim 1 wherein the controller is operable to modify the first period of time by shortening the first period of time.

### Claim 3 (depends on 1)

The electrical combination as set forth in claim 1 wherein the controller is operable to receive the individual state of charge of each battery cell of the plurality of battery cells.

### Claim 4 (depends on 1)

The electrical combination as set forth in claim 1 wherein the controller is located within the housing of the battery charger.

### Claim 5 (depends on 1)

The electrical combination as set forth in claim 1 wherein the controller includes a first charging module and a second charging module, the first charging module operable to provide a first charging current to the battery pack and the second charging module operable to provide a second charging current to the battery pack.

### Claim 6 (depends on 5)

The electrical combination as set forth in claim 5 wherein the first charging current and the second charging current differ in one of average current amplitude and duty-cycle.

### Claim 7 (depends on 6)

The electrical combination as set forth in claim 6 wherein the first charging module includes a fast charge module.

### Claim 8 (depends on 7)

The electrical combination as set forth in claim 7 wherein the first charging current includes a fast charge current.

### Claim 9

A method of operating an electrical combination, the electrical combination including a battery charger including a housing, at least one terminal to electrically connect to a battery pack supported by the housing, the battery pack including a plurality of lithium-based battery cells, each battery cell of the plurality of battery cells having an individual state of charge, and a controller, the method comprising:
controlling, with the controller, the battery charger to supply a charging current to the battery pack through the at least one terminal, the controller being operable to control the charging current being supplied to the battery pack based at least in part on the individual state of charge of at least one battery cell; and
controlling, with the controller, the battery charger to supply the charging current to the battery pack by controlling the battery charger to supply the charging current in a plurality of pulses of charging current, the plurality of pulses each having a first period of time, in which the charging current is being supplied to the battery pack at a predefined amplitude, and a second period of time, in which the supply of charging current is suspended, controlling the battery charger to supply the charging current including modifying, with the controller, the first period of time and controlling, with the controller, the second period of time to be constant.

### Claim 10 (depends on 9)

The method as set forth in claim 9 wherein the controller modifies the first period of time by shortening the first period of time.

### Claim 11 (depends on 9)

The method as set forth in claim 9 wherein the controller receives the individual state of charge of each battery cell of the plurality of battery cells.

### Claim 12 (depends on 9)

The method as set forth in claim 9 wherein the controller is located within the housing of the battery charger.

### Claim 13 (depends on 9)

The method as set forth in claim 9 further comprising implementing, with the controller, a first charging module and a second charging module, the first charging module operable to provide a first charging current to the battery pack and the second charging module operable to provide a second charging current to the battery pack.

### Claim 14 (depends on 13)

The method as set forth in claim 13 wherein the first charging current and the second charging current differ in one of average current amplitude and duty-cycle.

### Claim 15 (depends on 14)

The method as set forth in claim 14 wherein the first charging module includes a fast charge module.

### Claim 16 (depends on 15)

The method as set forth in claim 15 wherein the first charging current includes a fast charge current.