Battery system monitoring apparatus and electric storage device including the same for balancing a plurality of battery cells by discharging them based on voltage dependent turn-on resistance adapting of the balancing switch

• US 9,673,640 B2
• Filed: 10/20/2011
• Issued: 06/06/2017
• Est. Priority Date: 10/20/2011
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Emori, Akihiko, Kudo, Akihiko, Kikuchi, Mutsumi
• Primary Examiner(s): Grant, Robert
• Assistant Examiner(s): TRISCHLER, JOHN T
• Application Number:
  US14/352,227
• Publication Number:
  US 20140327400A1
• Time in Patent Office: 2,056 Days
• Field of Search: 320116, 320118
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• 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: H02M 7/44 by static converters
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A battery system monitoring apparatus for monitoring a cell group having a plurality of battery cells, and includes a cell controller IC which monitors and controls the states of the plurality of battery cells. A battery controller controls the cell controller IC and a plurality of voltage detection lines measure the voltage across the terminals of the battery cell. The voltage detection lines connect positive and negative electrodes of the battery cell, respectively, to a plurality of voltage input terminals of the cell controller IC. A power line connects the positive electrode of the battery cell having the highest potential among the plurality of battery cells to a power supply terminal of the cell controller IC and a ground line which connects the negative electrode of the battery cell having the lowest potential among the plurality of battery cells to a ground terminal of the cell controller IC.

Claims

1. A battery system monitoring apparatus for monitoring a cell group having a plurality of battery cells connected in series, the battery system monitoring apparatus comprising:

a cell controller integrated circuit (IC) which monitors and controls the states of the plurality of battery cells of the cell group;

a battery controller which controls the cell controller IC;

a plurality of voltage detection lines for measuring the voltage across the terminals of the battery cells, the voltage detection lines connecting positive and negative electrodes of the battery cells, respectively, to a plurality of voltage input terminals of the cell controller IC;

a power line which connects the positive electrode of the battery cell having the highest potential among the plurality of battery cells to a power supply terminal of the cell controller IC; and

a ground line which connects the negative electrode of the battery cell having the lowest potential among the plurality of battery cells to a ground terminal of the cell controller IC, wherein

the battery cells are each provided with a balancing switch which performs balancing discharge on the battery cell, the balancing switch being connected between the voltage detection line connected to the positive electrode of the battery cell and the voltage detection line connected to the negative electrode, and a balancing resistor connected in series to the balancing switch,

the voltage detection lines are provided with voltage input resistors in series, and

the battery controller controls the cell controller IC and sets the effective resistance value of the balancing switch to a predetermined value (Rb_ef) calculated from the resistance value of a voltage input resistor (R_CV) provided to the voltage detection line, an overcharge protection voltage value of the battery cell (V_MAX), and a voltage value when the battery cell has a state of change (SOC) of 100% (V_F) according to the formula Rb_ef=R_CV×

V_F/(V_max−

V_F).

2. The battery system monitoring apparatus according to claim 1, wherein the effective resistance value of the balancing switch is set to the value calculated from the resistance value of the balancing resistor and a duty cycle of on and off of the balancing switch.

3. The battery system monitoring apparatus according to claim 1, comprising a plurality of the cell controller ICs to monitor a plurality of the cell groups.

4. A method for calculating the predetermined value based on the battery system monitoring apparatus according to claim 1.

5. An electric storage device including the battery system monitoring apparatus according to claim 1, and a battery system.

6. An electric drive apparatus comprising the electric storage device according to claim 5.