Battery protective circuit for short circuit detection and battery pack comprising same
A battery protective circuit may include: a first switch connected between a negative pack terminal of a battery pack and an output node to control an electrical connection between the negative pack terminal and the output node; a first resistor connected between the output node and a ground; and a controller configured to control on or off of the first switch and to determine a short circuit state between pack terminals of the battery pack based on an output voltage of the output node.
1 . A battery protective circuit comprising:
a first switch connected between a negative pack terminal of a battery pack and an output node to control an electrical connection between the negative pack terminal and the output node;
a second switch connected between a control terminal of the first switch and a ground;
a first resistor connected between the output node and the ground;
a second resistor connected between the first switch and the output node, the second resistor being in a current path of the first switch and configured to conduct a same current as that passing through the first switch, each of the first resistor and the second resistor being directly connected to the output node, the first resistor being directly connected to the ground;
a diode having a first terminal directly connected to the negative pack terminal and having a second terminal directly connected to a first terminal of the first switch;
a third resistor directly connected between the control terminal of the first switch and a terminal of the second switch;
a fourth resistor directly connected between the second terminal of the diode and the control terminal of the first switch; and
a controller configured to detect an output voltage of the output node, to control an on state or an off state of the first switch, and to determine a short circuit state between pack terminals of the battery pack based on the output voltage of the output node.
2 . The battery protective circuit of claim 1 , wherein
the second switch is configured to control a voltage applied to the control terminal of the first switch depending on a control signal applied from the controller.
3 . The battery protective circuit of claim 2 , wherein the first switch and the second switch are a P-channel transistor and an N-channel transistor, respectively, and on or off of the P-channel transistor is controlled depending on a voltage applied to the control terminal of the P-channel transistor through the N-channel transistor.
4 . The battery protective circuit of claim 1 , wherein the controller turns on the first switch in a state where a discharge control switch of the battery pack is turned off.
5 . A battery pack comprising:
a plurality of pack terminals;
a battery module configured to include one or more cells;
a discharge control switch connected between one of the pack terminals and the battery module to connect or cut off a discharge path of the battery module;
a first switch connected between an output node and a negative pack terminal among the pack terminals to control electrical connection between the negative pack terminal and the output node;
a second switch connected between a control terminal of the first switch and a ground;
a first resistor connected between the output node and the ground;
a second resistor connected between the first switch and the output node, the second resistor being in a current path of the first switch and configured to conduct a same current as that passing through the first switch, each of the first resistor and the second resistor being directly connected to the output node, the first resistor being directly connected to the ground;
a diode having a first terminal directly connected to the negative pack terminal and having a second terminal directly connected to a first terminal of the first switch;
a third resistor directly connected between the control terminal of the first switch and a terminal of the second switch;
a fourth resistor directly connected between the second terminal of the diode and the control terminal of the first switch; and
a controller configured to detect an output voltage of the output node, to control an on state or an off state of the first switch and to determine a short circuit state between the pack terminals based on the output voltage of the output node.
6 . The battery pack of claim 5 , wherein
the second switch is configured to control a voltage applied to the control terminal of the first switch depending on a control signal applied from the controller.
7 . The battery pack of claim 6 , wherein the first switch and the second switch are a P-channel transistor and an N-channel transistor, respectively, and on or off of the P-channel transistor is controlled depending on a voltage applied to the control terminal of the P-channel transistor through the N-channel transistor.
8 . The battery pack of claim 7 , wherein the controller turns on the second switch in a state where the discharge control switch is turned off to monitor a short circuit between the pack terminals.
9 . The battery pack of claim 8 , wherein the controller monitors a short circuit between the pack terminals by turning on the second switch for a predetermined time before the discharge control switch is switched to an on state by starting an operation of a load connected through the pack terminals.
10 . The battery pack of claim 8 , wherein when the discharge control switch is turned off due to a short circuit during operation of a load connected through the pack terminals, the controller periodically monitors the short circuit between the pack terminals by periodically turning on the second switch until the short circuit is released.