Overcurrent simulation method when nail penetrates secondary battery and recording medium storing the program

• US 9,495,493 B2
• Filed: 10/28/2014
• Issued: 11/15/2016
• Est. Priority Date: 11/25/2013
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Seo, Se-Wook, Kang, Dal-Mo, Jung, Seung-Hun
• Primary Examiner(s): Le, Son
• Assistant Examiner(s): Zakaria, Akm
• Application Number:
  US14/525,310
• Publication Number:
  US 20150145525A1
• Time in Patent Office: 749 Days
• Field of Search: 324/555
• US Class Current: 1/1
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/4285 Testing apparatus
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 2200/00 Safety devices for primary or secondary batteries
• CPC Class Codes: H01M 50/578 in response to pressure
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed is an overcurrent simulation method when a nail penetrates a secondary battery and a recording medium storing the program. The overcurrent simulation method according to the present disclosure constructs a safety device and a secondary battery equivalent circuit, and produces a nail penetration effect by changing a resistance value. In this instance, various current simulations may be obtained by changing a first metal sheet and a second metal sheet included in the safety device, and a resistance value limiting an overcurrent may be calculated.

Claims

1. An overcurrent simulation method which simulates an overcurrent, in the event of penetration of at least two secondary batteries and a safety device, based on a resistance value of the safety device using an electronic circuit analysis program operating by a microprocessor, the overcurrent simulation method comprising:

(a) receiving, by the microprocessor, an input of;

an equivalent circuit of the safety device including a first metal sheet, an insulator member and a second metal sheet, wherein the insulator member is interposed between the first metal sheet and the second metal sheet, and the first metal sheet and the second metal sheet would be electrically connected by a conductive object when the conductive object penetrates the safety device and the at least two secondary batteries, and an equivalent circuit of at least two secondary batteries including an overcurrent channel via which an overcurrent flows in the event of penetration, through a variable resistor device;

(b) variously setting, by the microprocessor, a resistance value of a circuit equivalent of the first metal sheet and a circuit equivalent of the second metal sheet;

(c) changing, by the microprocessor, a resistance value of a circuit equivalent of the insulator member and a resistance value of the variable resistor device in the equivalent circuit of at least two secondary batteries to a resistance value of a conductive object sequentially in an order in which the conductive object penetrates the safety device and the at least two secondary batteries;

(d) outputting, by the microprocessor, a current value on a circuit equivalent of the overcurrent channel over time using the electronic circuit analysis program; and

(e) calculating, by the microprocessor, a resistance value of the circuit equivalent of the first metal sheet and the circuit equivalent of the second metal sheet allowing a minimum magnitude of current to flow in the circuit equivalent of the overcurrent channel.

2. The overcurrent simulation method according to claim 1, wherein the step (a) further comprises receiving an input of connection wiring information between the equivalent circuit of at least two secondary batteries and the equivalent circuit of the safety device.

3. The overcurrent simulation method according to claim 2, wherein the equivalent circuit of at least two secondary batteries includes a voltage source exhibiting an output voltage of the equivalent circuit of at least two secondary batteries.

4. The overcurrent simulation method according to claim 3, wherein the equivalent circuit of at least two secondary batteries further comprises a resistor device exhibiting an internal resistance of the equivalent circuit of at least two secondary batteries, and a capacitance device exhibiting an internal capacitance of the equivalent circuit of at least two secondary batteries.

5. The overcurrent simulation method according to claim 4, wherein the internal resistance of the equivalent circuit of at least two secondary batteries has resistance values corresponding to a secondary battery case, a cathode plate, a cathode active material, a separator, an anode plate, and an anode active material, and resistor devices representing the cathode plate, the cathode active material, the separator, and the anode plate, and the anode active material are electrically connected in series.

6. The overcurrent simulation method according to claim 5, wherein, in the equivalent circuit of at least two secondary batteries, the internal capacitance is electrically connected in parallel to the resistor devices exhibiting the resistance of the cathode active material and the anode active material, respectively.

7. The overcurrent simulation method according to claim 6, wherein the overcurrent channel comprises the variable resistor device changing in resistance value based on preset time information, and a current sensor to measure the current value flowing through the variable resistor device.

8. The overcurrent simulation method according to claim 7, wherein an initial value of the variable resistor device is a resistance value representing an insulation state to show a state before the at least two secondary batteries is pierced.

9. A recording medium storing an electronic circuit analysis program, the electronic circuit analysis program used to simulate an overcurrent, in the event of penetration of a at least two secondary batteries and a safety device, based on a resistance value of the safety device, the recording medium comprising:

(a) receiving an input of an equivalent circuit of the safety device including a first metal sheet, an insulator member and a second metal sheet, wherein the insulator member is interposed between the first metal sheet and the second metal sheet, and the first metal sheet and the second metal sheet are electrically connected by a conductive object when the conductive object penetrates the safety device and the at least two secondary batteries and an equivalent circuit of at least two secondary batteries including an overcurrent channel via which an overcurrent flows in the event of penetration, through a variable resistor device;

(b) variously setting a resistance value of the first metal sheet and the second metal sheet;

(c) changing a resistance value of the circuit equivalent of the insulator member and a resistance value of the variable resistor device in the equivalent circuit of at least two secondary batteries to a resistance value of a conductive object sequentially in an order in which the conductive object penetrates the safety device and the at least two secondary batteries;

(d) outputting a current value on the circuit equivalent of the overcurrent channel over time using the electronic circuit analysis program; and

(e) calculating a resistance value of the circuit equivalent of the first metal sheet and the circuit equivalent of the second metal sheet allowing a minimum magnitude of current to flow in the circuit equivalent of the overcurrent channel.

10. The recording medium storing an electronic circuit analysis program according to claim 9, wherein the step (a) further comprises receiving an input of connection wiring information between the equivalent circuit of at least two secondary batteries and the equivalent circuit of the safety device.

11. The recording medium storing an electronic circuit analysis program according to claim 10, wherein the equivalent circuit of at least two secondary batteries includes a voltage source exhibiting an output voltage of the equivalent circuit of at least two secondary batteries.

12. The recording medium storing an electronic circuit analysis program according to claim 11, wherein the equivalent circuit of at least two secondary batteries further comprises a resistor device exhibiting an internal resistance of the equivalent circuit of at least two secondary batteries, and a capacitance device exhibiting an internal capacitance of the equivalent circuit of at least two secondary batteries.

13. The recording medium storing an electronic circuit analysis program according to claim 12, wherein the internal resistance of the equivalent circuit of at least two secondary batteries has resistance values corresponding to a secondary battery case, a cathode plate, a cathode active material, a separator, an anode plate, and an anode active material, and resistor devices representing the cathode plate, the cathode active material, the separator, and the anode plate, and the anode active material are electrically connected in series.

14. The recording medium storing an electronic circuit analysis program according to claim 13, wherein, in the equivalent circuit of at least two secondary batteries, the internal capacitance is electrically connected in parallel to the resistor devices exhibiting the resistance of the cathode active material and the anode active material, respectively.

15. The recording medium storing an electronic circuit analysis program according to claim 14, wherein the overcurrent channel comprises the variable resistor device changing in resistance value based on preset time information, and a current sensor to measure the current value flowing through the variable resistor device.

16. The recording medium storing an electronic circuit analysis program according to claim 15, wherein an initial value of the variable resistor device is a resistance value representing an insulation state to show a state before the at least two secondary batteries is pierced.