Electricity storage system

• US 10,158,241 B2
• Filed: 12/03/2012
• Issued: 12/18/2018
• Est. Priority Date: 12/03/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tanabe, Yukinari, Nishi, Yuji, Kaiya, Hiroyuki, Tanaka, Hiromasa, Kaita, Keiji, Ito, Motoi
• Primary Examiner(s): Berhanu, Samuel
• Application Number:
  US14/649,014
• Publication Number:
  US 20150357856A1
• Time in Patent Office: 2,206 Days
• Field of Search: 320163, 320104-105
• CPC Class Codes: H02H 3/20 responsive to excess voltage
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

An electricity storage system includes an electricity storage block including an electricity storage element for performing charging and discharging; a relay switched between an ON state in which the electric storage block is connected to a load and an OFF state in which a connection between the electricity storage block and the load is cut off; a controller for controlling the ON state and the OFF state of the relay; and a current cutoff circuit so as to cut off energization of the electricity storage block. The current cutoff circuit has an alarm circuit to indicate that the electricity storage block is in an overcharged state by comparing a voltage value of the electricity storage block and a threshold; a latch circuit retains the alarm signal; and a transistor receives an output signal of the latch circuit and switches the relay from the ON state to the OFF state.

Claims

1. An electricity storage system comprising:

an electricity storage block including an electricity storage element for performing charging and discharging and capable of being connected to a load;

a relay configured to be switched between an ON state and an OFF state, the electricity storage block and the load being connected when the relay is in the ON state, and a connection between the electricity storage block and the load being cut off when the relay is in the OFF state;

a controller configured to control the ON state and the OFF state of the relay; and

a current cutoff circuit configured to switch the relay from the ON state to the OFF state, so as to cut off energization of the electricity storage block,

the current cutoff circuit including;

an alarm circuit configured to output an alarm signal indicating that the electricity storage block is in an overcharged state by comparing a voltage value of the electricity storage block and a threshold;

a latch circuit for retaining the alarm signal; and

a transistor configured to receive an output signal from the latch circuit and switching the relay from the ON state to the OFF state.

2. The electricity storage system according to claim 1, wherein

the alarm circuit has a first comparator and a second comparator,

the first comparator configured to detect a potential difference between a positive electrode and a negative electrode of the electricity storage block, and

the second comparator configured to compare output of the first comparator with the threshold.

3. The electricity storage system according to claim 2, wherein the alarm circuit includes a filter circuit, the filter circuit being connected to an output line of the second comparator.

4. The electricity storage system according to claim 1, wherein the current cutoff circuit includes a photocoupler, the photocoupler being provided between the latch circuit and the transistor.

5. The electricity storage system according to claim 1, wherein current cutoff circuit includes a second filter circuit, the second filter circuit including a filter circuit that that is connected to a line for connecting the alarm circuit and the electricity storage block.

6. The electricity storage system according to claim 1, wherein current cutoff circuit has a Zener diode, a cathode of the Zener diode being connected to a positive electrode terminal of the electricity storage block, and an anode of the Zener diode being connected to a negative electrode terminal of the electricity storage block.

7. The electricity storage system according to claim 1 comprising:

an engine, wherein the electricity storage block outputs power that is converted to kinetic energy for traveling the vehicle and outputs power for starting the engine to the vehicle,

the current cutoff circuit includes a delay circuit being provided between the latch circuit and the transistor, and

the controller receives the output signal of the latch circuit and starts the engine.

8. The electricity storage system according to claim 1, wherein

the current cutoff circuit includes an OR circuit, the OR circuit being provided between the latch circuit and the transistor, and

the OR circuit receives the output signal of the latch circuit or a signal that is output from the controller to stop an operation of the current cutoff circuit, and thus outputs a signal for switching the transistor to an OFF state.

10. The electricity storage system according to claim 1, wherein a plural electricity storage blocks are electrically connected in series.

9. An electricity storage system comprising:

an electricity storage block including an electricity storage element for performing charging and discharging;

a relay configured to be switched between an ON state and an OFF state, the electricity storage block and the load being connected when the relay is in the ON state, and a connection between the electricity storage block and the load being cut off when the relay is in the OFF state;

a controller configured to control the ON state and the OFF state of the relay; and

a current cutoff circuit configured to switch the relay from the ON state to the OFF state, so as to cut off energization of the electricity storage block,

the current cutoff circuit including;

an alarm circuit configured to output an alarm signal indicating that the electricity storage block is in an overcharged state by comparing a voltage value of the electricity storage block and a threshold;

the alarm circuit including

a comparator, the comparator having a hysteresis characteristic that is larger than a voltage drop amount of the electricity storage block after the energization of the electricity storage block is cut off, and

a transistor configured to receive an output signal of the alarm circuit and switch the relay from the ON state to the OFF state.