# US 2019/0356142 A1 · Method and system for charging multi-cell lithium-based battery packs

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2019/0356142 A1
- Document ID: US20190356142A1
- Status: Published application
- Kind: A1
- Application number: 16/531,382
- Filed: 2019-08-05
- Published: 2019-11-21
- 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/US20190356142A1

## 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

A battery charger, comprising:
a housing;
at least two terminals including a power terminal and a sense terminal to electrically connect to a power tool battery pack supported by the housing, the power tool 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
supply a charging current to the power tool battery pack through the power terminal,
receive an individual state of charge of at least one of the plurality of battery cells over the sense terminal,
control the charging current being supplied to the power tool battery pack based at least in part on the individual state of charge of the at least one of the plurality of battery cells,
control the charging current being supplied to the power tool battery pack by controlling the battery charger to supply the charging current in a plurality of pulses, the plurality of pulses each having a first period of time during which the charging current is being supplied to the power tool battery pack at a predefined amplitude, and a second period of time during which the supply of charging current is suspended, and
control the charging current being supplied to the power tool 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 battery charger of 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 battery charger of claim 1, wherein the controller is operable to receive the individual state of charge of each battery cell of the plurality of battery cells over the sense terminal.

### Claim 4 (depends on 1)

The battery charger of 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 power tool battery pack and the second charging module operable to provide a second charging current to the power tool battery pack.

### Claim 5 (depends on 4)

The battery charger of claim 4, wherein the first charging current and the second charging current differ in one of average current amplitude and duty-cycle.

### Claim 6 (depends on 5)

The battery charger of claim 5, wherein the first charging module includes a fast charge module.

### Claim 7 (depends on 6)

The battery charger of claim 6, wherein the fast charge module is operable to provide a fast charge current to the power tool battery pack.

### Claim 8

A method of operating a battery charger, the battery charger including a housing, a controller, at least two terminals including a power terminal and a sense terminal to electrically connect to a power tool battery pack supported by the housing, the power tool 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, the method comprising:
supplying a charging current to the power tool battery pack through the power terminal;
receiving, by the controller, an individual state of charge of at least one of the plurality of battery cells over the sense terminal;
controlling, by the controller, the charging current being supplied to the power tool battery pack based at least in part on the individual state of charge of the at least one of the plurality of battery cells;
controlling, by the controller, the charging current being supplied to the power tool battery pack by controlling the battery charger to supply the charging current in a plurality of pulses, the plurality of pulses each having a first period of time during which the charging current is being supplied to the power tool battery pack at a predefined amplitude, and a second period of time during which the supply of charging current is suspended, and
controlling, by the controller, the charging current being supplied to the power tool battery pack by modifying the first period of time and controlling the second period of time to be constant.

### Claim 9 (depends on 8)

The method of claim 8, further comprising modifying, by the controller, the first period of time by shortening the first period of time.

### Claim 10 (depends on 8)

The method of claim 8, further comprising receiving, by the controller, the individual state of charge of each battery cell of the plurality of battery cells over the sense terminal.

### Claim 11 (depends on 8)

The method of claim 8, further comprising:
implementing, by the controller, a first charging module operable to provide a first charging current to the power tool battery pack; and
implementing, by the controller, a second charging module operable to provide a second charging current to the power tool battery pack.

### Claim 12 (depends on 11)

The method of claim 11, wherein the first charging current and the second charging current differ in one of average current amplitude and duty-cycle.

### Claim 13 (depends on 12)

The method of claim 12, wherein the first charging module includes a fast charge module.

### Claim 14 (depends on 13)

The method of claim 13, wherein the fast charge module is operable to provide a fast charge current to the power tool battery pack.