# US 9,520,738 B2 · Inductive charging device for a battery device

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- Number: US 9,520,738 B2
- Document ID: US9520738B2
- Status: Granted
- Kind: B2
- Application number: 14/134,582
- Filed: 2013-12-19
- Published: 2014-06-26
- Granted: 2016-12-13
- Earliest claimed: 2012-12-21
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Marcin Rejman; Guenter Lohr; Juergen Mack; Dragan Krupezevic
- Web page: https://patentgrep.com/patent/US9520738B2

## CPC

- H02J 50/005: {Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices}
- H02J 7/731: {specially adapted for holding portable devices containing batteries (H02J7/751 takes precedence)}
- H02J 50/10: using inductive coupling
- H02J 50/90: involving detection or optimisation of position, e.g. alignment
- H02J 7/70: characterised by the mechanical construction
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY

## Abstract

A charging system for a battery device of a handheld tool includes a charging device provided to inductively charge the battery device in a charging operation, the charging device having at least one induction charging unit which has at least one charging coil having a main coil extension. A gap is provided between the battery device and the charging device in a charging operation. A ratio between (i) the at least one main coil extension and (ii) a minimum clearance between the at least one charging coil and a surface defining the gap is at most 30/1.

## Claims

### Claim 1

A system, comprising:
a battery device including a first induction charging unit that includes at least one first charging coil having a main coil extension; and
a charging device configured to transmit a charging energy inductively to the battery device, the charging device including a second induction charging unit that includes at least one second charging coil having a main coil extension;
wherein:
between the battery device and charging device is a gap delimited by a surface of the battery device and a surface of the charging device;
a ratio of (i) the main coil extension of the at least one first charging coil to (ii) a clearance between the at least one first charging coil and the surface of the battery device is at most 30/1;
a ratio of (i) the main coil extension of the at least one second charging coil to (ii) a clearance between the at least one second charging coil and the surface of the charging device is at most 30/1; wherein at least one of the ratios is at least 7/1.

### Claim 2 (depends on 1)

The system as recited in claim 1, wherein at least one of the ratios is between 20/1 and 14/1.

### Claim 3 (depends on 1)

The system as recited in claim 1, wherein the at least one second charging coil has a main coil extension of at least 50 mm.

### Claim 4 (depends on 1)

The system as recited in claim 1, wherein the battery device is of a handheld tool.