# US 12,184,102 B2 · Protective circuit and energy storage apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,184,102 B2 - Document ID: US12184102B2 - Status: Granted - Kind: B2 - Application number: 17/756,509 - Filed: 2020-12-02 - Published: 2023-01-12 - Granted: 2024-12-31 - Earliest claimed: 2019-12-10 - Assignees: GS Yuasa International Ltd. - Applicants: GS Yuasa International Ltd. - Inventors: Masakatsu Fujimatsu; Kiyohiro Fujita; Shigeki Hattori; Akimasa Sugiura - Web page: https://patentgrep.com/patent/US12184102B2 ## CPC - H02J 7/61: against overcharge - H02J 7/64: against overvoltage - H02H 3/087: for DC applications - H02J 7/1415: {with a generator driven by a prime mover other than the motor of a vehicle} - H02J 7/345: {using capacitors as storage or buffering devices} - H02J 7/62: against overcurrent - H02J 7/663: {using battery or load disconnect circuits (H02J9/002 takes precedence)} - H02J 7/855: {with circuits adapted for supplying loads from the battery} - H03K 17/08122: {in field-effect transistor switches} - H03K 17/08142: {in field-effect transistor switches} - H02J 2105/33: exchanging power with road vehicles - H02J 2105/37: exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] - H03K 17/6874: {in a symmetrical configuration} - Y02E 60/10: Energy storage using batteries - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A protection circuit 60 is provided with: switches 61, 62 positioned on a power line PL of an electricity storage element 22 and a load 12; first protection elements 63, 64, 65 connected in parallel with the switches 61, 62 and absorbing surge caused when the switches 61, 62 open and cut off discharge current; and a second protection element 66 connected in parallel with the load and flowing, back to the load, the surge caused when the switches 61, 62 open and cut off the discharge current. ## Claims ### Claim 1 An energy storage apparatus protective circuit comprising: a container provided with a pair of external terminals; an energy storage device housed in the container; and a protective circuit housed in the container and comprising: back-to-back connected FETs located on a power line from the energy storage device to the pair of external terminals; a first protective element that is connected in parallel to the FETs and absorbs a surge generated when the FETs are opened and discharge current is cut off; and a second protective element that is connected in parallel to a load, which is connected to the pair of external terminals and is outside the container, and returns the surge, which is generated when the FETs are opened and discharge current is cut off, to the load, wherein: the first protective element includes a plurality of the first protective elements including: a capacitor connected in parallel to the switch; and a Zener diode connected in parallel to the switch, and the energy storage apparatus has a rating of 12 volts. ### Claim 2 (depends on 1) The energy storage apparatus according to claim 1, wherein absorption of the surge by the first protective element is faster in response than return of the surge by the second protective element. ### Claim 3 (depends on 1) The energy storage apparatus according to claim 1, wherein a signal line from a drive circuit to a control terminal of each of the FETs has a resistor. ### Claim 4 (depends on 1) The energy storage apparatus according to claim 1, wherein the pair of external terminals are connected to electrodes of the energy storage device, and the second protective element is a freewheel diode. ### Claim 5 (depends on 1) The energy storage apparatus according to claim 1, further comprising a circuit board, which is housed in the container and is placed between the energy storage device and a lid body of the container, wherein the protective circuit is constructed on the circuit board. ### Claim 6 (depends on 1) The energy storage apparatus according to claim 1, wherein the energy storage device comprises lithium ion secondary batteries constructing an assembled battery. ### Claim 7 (depends on 1) The energy storage apparatus according to claim 1, wherein the back-to-back connected FETs comprise a pair of N channel FETs located on the power line between a negative electrode of the energy storage device and a negative external terminal of the pair of external terminals. ### Claim 8 An energy storage apparatus comprising: a container provided with a pair of external terminals; an energy storage device housed in the container; and a protective circuit housed in the container and comprising: back-to-back connected FETs located on a power line from the energy storage device to the pair of external terminals; a first protective element that is connected in parallel to the FETs and absorbs a surge generated when the FETs are opened and discharge current is cut off; and a second protective element that is connected in parallel to a load, which is connected to the pair of external terminals and is outside the container, and returns the surge, which is generated when the FETs are opened and discharge current is cut off, to the load, wherein the energy storage apparatus has a rating of 12 volts. ### Claim 9 (depends on 8) The energy storage apparatus according to claim 8, wherein absorption of the surge by the first protective element is faster in response than return of the surge by the second protective element. ### Claim 10 (depends on 8) The energy storage apparatus according to claim 8, wherein a signal line from a drive circuit to a control terminal of each of the FETs has a resistor. ### Claim 11 (depends on 8) The energy storage apparatus according to claim 8, further comprising a circuit board, which is housed in the container and is placed between the energy storage device and a lid body of the container, wherein the protective circuit is constructed on the circuit board. ### Claim 12 (depends on 8) The energy storage apparatus according to claim 8, wherein the energy storage device comprises lithium ion secondary batteries constructing an assembled battery. ### Claim 13 (depends on 8) The energy storage apparatus according to claim 8, wherein the back-to-back connected FETs comprise a pair of N channel FETs located on the power line between a negative electrode of the energy storage device and a negative external terminal of the pair of external terminals.