BALANCER CIRCUIT AND BATTERY UNIT USING SAME

• US 20150244189A1
• Filed: 09/10/2013
• Published: 08/27/2015
• Est. Priority Date: 10/24/2012
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Baba, Kensuke
• Application Number:
  US14/432,259
• Publication Number:
  US 20150244189A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A balancer circuit connected to a battery pack having a plurality of secondary cells connected in series, and comprising: a capacitance element; and a switching unit that switches the connection state for both ends of the capacitance element between a state in which same are connected to both ends of one of the secondary cells and a state in which same are connected to both ends of another secondary cell. The balancer circuit corrects the balance between the voltages for the plurality of secondary cells by executing a switching operation that repeats said switching, and comprises a detection unit that detects said state of balance by detecting the size of the overshoot component in a voltage waveform at sites connected to the capacitance element.

Claims

1. A balancer circuit connected to a battery pack in which a plurality of secondary batteries are connected in series, comprising:

a capacitance element, and

a switching portion that performs a switchover of a connection state of both ends of the capacitance element between states which include;

a state where both ends of the capacitance element are connected to both ends of any one of the secondary batteries; and

a state where both ends of the capacitance element are connected to both ends of another one of the secondary batteries,

wherein the balancer circuit corrects a voltage balance state among the plurality of secondary batteries by executing a switching operation that performs repeatedly the switchover, and

the balancer circuit includes a detection portion that detects the balance state by detecting a size of an overshoot component of a voltage waveform at a point connected to the capacitance element.

2. The balancer circuit according to claim 1, wherein

the capacitance element is a part that has a lead wire connected to an electrode of the capacitance element, and

the detection portion includes:

a ferrite beads core through which the lead wire passes,

a power line which passes through the ferrite beads core together with the lead wire, and

detects the balance state based on a voltage signal output from the power line.

3. The balancer circuit according to claim 2, wherein

the switching operation is controlled based on a detection result of the balance state.

4. The balancer circuit according to claim 3, wherein

a period of the switching operation is adjusted based the detection result of the balance state.

5. A battery unit comprising:

a battery pack in which a plurality of secondary batteries are connected in series, and

a balancer circuit according to claim 1 that corrects a voltage balance state among the plurality of secondary batteries.

6. A battery unit comprising:

a battery pack in which a plurality of secondary batteries are connected in series, and

a balancer circuit according to claim 2 that corrects a voltage balance state among the plurality of secondary batteries.

7. A battery unit comprising:

a battery pack in which a plurality of secondary batteries are connected in series, and

a balancer circuit according to claim 3 that corrects a voltage balance state among the plurality of secondary batteries.

8. A battery unit comprising:

a battery pack in which a plurality of secondary batteries are connected in series, and

a balancer circuit according to claim 4 that corrects a voltage balance state among the plurality of secondary batteries.