Battery pack and method for detecting disconnection of same

1. A battery pack, comprising:

an assembled battery including a plurality of secondary battery cells connected at least in series;

a voltage detector which detects a terminal voltage of each of said plurality of secondary battery cells;

a charge/discharge controller which controls charge/discharge of the assembled battery based on the terminal voltage of each cell detected by the voltage detector;

a short-circuiting section which short-circuits a node between cells to the high voltage side or the low voltage side of a power line, or which short-circuits nodes between the cells to each other; and

a disconnection detector which controls conduction/non-conduction of said short-circuiting section and which detects a disconnection of the connection line from the voltage detector to the node between the cells, based on a state of controlling the conduction/non-conduction, and at least one of a voltage at the node between the cells detected by said voltage detector, a voltage of the high voltage side or the low voltage side of the power line, and a terminal voltage of each cell,

wherein:

the short-circuiting section includes a series circuit made up of a resistor and a switch, and said series circuit short-circuits the high voltage side of the power line and the node between the cells respectively to the low voltage side of the power line.

2. A battery pack according to claim 1 , wherein the voltage detector and the short-circuiting section are integrally constructed as an ASIC.

3. A battery pack, comprising:

an assembled battery including a plurality of secondary battery cells connected at least in series;

a voltage detector which detects a terminal voltage of each of said plurality of secondary battery cells;

a charge/discharge controller which controls charge/discharge of the assembled battery based on the terminal voltage of each cell detected by the voltage detector;

a short-circuiting section which short-circuits a node between cells to the high voltage side or the low voltage side of a power line, or which short-circuits nodes between the cells to each other; and

a disconnection detector which controls conduction/non-conduction of said short-circuiting section and which detects a disconnection of the connection line from the voltage detector to the node between the cells, based on a state of controlling the conduction/non-conduction, and at least one of a voltage at the node between the cells detected by said voltage detector, a voltage of the high voltage side or the low voltage side of the power line, and a terminal voltage of each cell,

wherein:

said voltage detector includes:

an analog/digital converter which measures a voltage of the node between cells, and

an input switching section capable of selectively connecting the node between the cells to the analog/digital converter,

wherein the node between the cells is short-circuited by said short-circuiting section after being connected to the analog/digital converter by said input switching section.

4. A battery pack according to claim 3 , further comprising:

a cell selector which controls said short-circuit section to short-circuit the node between the cells and the analog/digital converter after connecting said node to the analog/digital converter by said input switching section.

5. A battery pack, comprising:

an assembled battery including a plurality of secondary battery cells connected at least in series

a voltage detector which detects a terminal voltage of each of said plurality of secondary battery cells;

a charge/discharge controller which controls charge/discharge of the assembled battery based on the terminal voltage of each cell detected by the voltage detector;

a short-circuiting section which short-circuits a node between cells to the high voltage side or the low voltage side of a power line, or which short-circuits nodes between the cells to each other; and

a disconnection detector which controls conduction/non-conduction of said short-circuiting section and which detects a disconnection of the connection line from the voltage detector to the node between the cells, based on a state of controlling the conduction/non-conduction, and at least one of a voltage at the node between the cells detected by said voltage detector, a voltage of the high voltage side or the low voltage side of the power line, and a terminal voltage of each cell,

wherein the charge/discharge controller:

performs a protection operation upon detecting an abnormality by comparing a result of detection by said voltage detector with a predetermined threshold value, and

further includes a double protection IC, which detects a terminal voltage of each cell by said voltage detector, and which performs a protection operation upon detecting an abnormality by comparing a voltage detected by said voltage detector with a threshold voltage set to or above that of the charge/discharge controller.

6. A method for detecting a disconnection of a battery pack comprising an assembled battery including a plurality of secondary battery cells connected at least in series, comprising the steps of:

short-circuiting a node between cells to a high-voltage side or a low-voltage side of a power line, or short-circuiting the node between the cells to each other;

connecting selectively the node between the cells to an analog/digital converter which measures a voltage of the node between cells; and

detecting a disconnection of the connection line to the node between the cells, based on a short-circuit state in said short-circuiting step, and at least one of a voltage at the node between the cells after being short-circuited by said short-circuiting step, a voltage of the high voltage side or the low voltage side of the power line, and a terminal voltage of each cell,

wherein the node between the cells is short-circuited by said short-circuiting step after being connected to the analog/digital converter by said connecting step.