# US 2014/0191731 A1 · Method for charging lithium ion secondary battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191731 A1 - Document ID: US20140191731A1 - Status: Published application - Kind: A1 - Application number: 13/821,497 - Filed: 2012-09-04 - Published: 2014-07-10 - Earliest claimed: 2011-09-27 - Assignees: Hitachi Maxell, Ltd. - Inventors: Kazutoshi Miura - Web page: https://patentgrep.com/patent/US20140191731A1 ## CPC - H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00) - H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries - H02J 7/92: with prioritisation of loads or sources - H02J 7/977: {of the battery} - H01M 4/134: Electrodes based on metals, Si or alloys - Y02B 40/00: Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers - Y02E 60/10: Energy storage using batteries - Y02E 60/13: Energy storage using capacitors - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract CCCV charging is applied to a lithium ion secondary battery. During CC charging, a transition point Ta appears in temperature rise gradient when battery temperature rises along with the charging, and with the transition point Ta being a border, a temperature rise gradient in an initial T1 period is steeper than a temperature rise gradient in a T2 period following the T1 period. Based on charging time tT corresponding to timing at which the transition point Ta appears after start of the CC charging from a condition of the SOC of 0%, changeover time ts is set in a range of tT≦ts≦(tT×1.2). The CC charging is performed at a first current value until changeover time tS elapses after its start, and after the changeover time ts elapses, the CC charging is performed with a second current value larger than the first current value. ## Claims ### Claim 1 A method for charging a lithium ion secondary battery by constant current constant voltage (CCCV) charging, comprising: a step of performing constant current (CC) charging up to a predetermined set voltage; and a step of switching to constant voltage (CV) charging after the set voltage is reached, thus performing charging while reducing charging current so as to keep the set voltage, wherein the lithium ion secondary battery is composed using a negative electrode material containing Si, thereby having characteristics such that, during a period of the CC charging, a transition point Ta appears in a temperature rise gradient when temperature of the battery rises along with progression of the charging, and with the transition point Ta being a border, a temperature rise gradient in an initial T1 period is steeper than a temperature rise gradient in a T2 period following the T1 period, changeover time ts is set in a range of tT≦ts≦(tT×1.2), based on charging time tT corresponding to timing at which the transition point Ta appears after start of the CC charging from a condition of the SOC of 0%, obtained by measurement in advance, and during a period of the CC charging, the CC charging is performed at a first current value until the changeover time ts elapses after start of the charging, and after the changeover time ts elapses, the CC charging is performed at a second current value larger than the first current value. ### Claim 2 A method for charging a lithium ion secondary battery by constant current constant voltage (CCCV) charging, comprising: a step of performing constant current (CC) charging up to a predetermined set voltage; and a step of switching to constant voltage (CV) charging after the set voltage is reached, thus performing charging while reducing charging current so as to keep the set voltage, wherein the lithium ion secondary battery is composed using a negative electrode material containing Si, thereby having characteristics such that, during a period of the CC charging, a transition point Ta appears in a temperature rise gradient when temperature of the battery rises along with progression of the charging, and with the transition point Ta being a border, a temperature rise gradient in an initial T1 period is steeper than a temperature rise gradient in a T2 period following the T1 period, changeover time ts is set in a range of tT≦ts≦(tT×1.2), based on charging time tT corresponding to timing at which the transition point Ta appears after start of the CC charging from a condition of the SOC of 0%, obtained by measurement in advance, a charge state of the lithium ion secondary battery is determined before start of the charging, and during a period of the CC charging, when the charge state is before the transition point Ta, the CC charging is performed at a first current value until the changeover time ts elapses from start of the charging, and after the changeover time ts elapses, the CC charging is performed at a second current value larger than the first current value, and when the charge state exceeds the transition point Ta, the CC charging is performed at a second current value larger than the first current value. ### Claim 3 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein the SOC of the lithium ion secondary battery is measured before start of the charging, when the SOC is 10% or less, it is determined that the charge state is before the transition point Ta, and when the SOC exceeds 10%, it is determined that the charge state exceeds the transition point Ta. ### Claim 4 (depends on 1) The method for charging a lithium ion secondary battery according to claim 1, wherein the charging time tT is defined as charging time tT10 that elapses from a start of the charging at a condition of the SOC of 0% to time when the SOC reaches 10%, and changeover time ts1 representing the changeover time ts is set in a range of tT10≦ts1≦(tT10×1.2). ### Claim 5 (depends on 1) The method for charging a lithium ion secondary battery according to claim 1, wherein the charging time tT is defined as a charging time tTA that elapses from a start of the charging at a condition of the SOC of 0% to time when the transition point of a temperature rise gradient is detected, and changeover time ts2 representing the changeover time ts is set in a range of tTA≦ts2≦(tTA×1.2). ### Claim 6 (depends on 1) The method for charging a lithium ion secondary battery according to claim 1, wherein when 1C is defined as a current value at which the lithium ion secondary battery that is fully charged is discharged within one hour, the first current value is set in a range of 0.7 to 0.8C. ### Claim 7 (depends on 1) The method for charging a lithium ion secondary battery according to claim 1, wherein the second current value is set to 1.5C or more. ### Claim 8 (depends on 1) The method for charging a lithium ion secondary battery according to claim 1, wherein the SOC at completion of the T2 period is set so as to exceed 80%. ### Claim 9 (depends on 1) The method for charging a lithium ion secondary battery according to claim 1, wherein the lithium ion secondary battery is composed using a composite material (SiOx) having a structure in which ultra-fine particles of Si are dispersed in SiO2 as the negative electrode material. ### Claim 10 (depends on 9) The method for charging a lithium ion secondary battery according to claim 9, wherein the composite material (SiOx) is formed of a core containing a material in which an atomic ratio x of oxygen with respect to silicon is 0.5≦x≦1.5, and a covering layer of carbon covering a surface of the core. ### Claim 11 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein the charging time tT is defined as charging time tT10 that elapses from a start of the charging at a condition of the SOC of 0% to time when the SOC reaches 10%, and changeover time ts1 representing the changeover time ts is set in a range of tT10≦ts1≦(tT10×1.2). ### Claim 12 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein the charging time tT is defined as a charging time tTA that elapses from a start of the charging at a condition of the SOC of 0% to time when the transition point of a temperature rise gradient is detected, and changeover time ts2 representing the changeover time ts is set in a range of tTA≦ts2≦(tTA×1.2). ### Claim 13 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein when 1C is defined as a current value at which the lithium ion secondary battery that is fully charged is discharged within one hour, the first current value is set in a range of 0.7 to 0.8C. ### Claim 14 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein the second current value is set to 1.5C or more. ### Claim 15 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein the SOC at completion of the T2 period is set so as to exceed 80%. ### Claim 16 (depends on 2) The method for charging a lithium ion secondary battery according to claim 2, wherein the lithium ion secondary battery is composed using a composite material (SiOx) having a structure in which ultra-fine particles of Si are dispersed in SiO2 as the negative electrode material. ### Claim 17 (depends on 16) The method for charging a lithium ion secondary battery according to claim 16, wherein the composite material (SiOx) is formed of a core containing a material in which an atomic ratio x of oxygen with respect to silicon is 0.5≦x≦1.5, and a covering layer of carbon covering a surface of the core.