Lithium-ion Battery Production and Testing
Learn how Hioki can help your Li-ion battery inspection/testing in each production process
Li-ion Battery Production Process
Active materials, conductive auxiliary agents, polymer binders, and organic solvents are mixed together to form an electrode slurry.
Coating, Drying, and Calendering
The electrode slurry is coated to copper and aluminum foil, dried, and calendared.
Winding or Stacking
A separator is inserted between the anode and cathode electrode sheets, and the electrode sheets are wound or stacked together.
The tabs of the layered electrode sheets are welded together, and collectors are welded to the tabs.
The covers and cases are welded together.
Electrolyte is filled via the electrolyte port.
The electrolyte port is closed.
Charging and Discharging
The cells are repeatedly charged and discharged.
The cells are stored for a certain period of time.
Quality is tested prior to shipment.
Li-ion Battery Inspection and Testing Methods
Structurally, it’ s necessary to keep the anode and cathode electrodes, as well as the electrodes and enclosure (case), insulated from each other. Failure to keep those components properly insulated—in other words, insufficient insulation resistance - could lead to a risk of ignition or fire accidents.
This type of testing measures the insulation resistance between battery cells’ anode and cathode electrodes, and between the electrodes and the enclosure.
If welds connecting tabs, collectors, and other battery components are insufficient, resistance between components will increase significantly, resulting in electrical energy loss and battery overheating. Such heating can reduce the battery’ s service life or cause fire.
This type of testing measures the resistance between welded components.
Voltage and temperature are recorded during the charging and discharging test process in order to monitor changes in battery state. Recorded data is then analyzed to detect defects and rank batteries.
This type of testing records fluctuations in battery cells’ voltage and temperature across multiple channels.
Although batteries’ internal resistance would ideally be zero, internal resistance exists due to a variety of factors. Internal resistance increases as a battery degrades.
This type of testing measures battery cells’ internal resistance.
A battery’ s voltage when it is not connected to any load is known as the open-circuit voltage (OCV). OCV values gradually decline due to self-discharge, a characteristic of batteries. When a battery has an internal defect, self-discharge increases, causing the OCV to decrease beyond the defined value.
This type of testing measures battery cells’ open-circuit voltage.
Testing times can be reduced by increasing the number of measurement channels, helping shorten lead times.
The DM7276, BT3562A, and BT4560 support up to 264, 132, and 72 channels, respectively. In addition, the SW1002 can connect to two different instruments, and the switching between them can be done automatically.
Electrode slurries consist of active materials, conductive auxiliary agents, polymer binders, and organic solvents. By ensuring these materials are uniformly dispersed, it is possible to produce batteries with favorable characteristics.
This process measures electrode slurries’ impedance. Calculations are then performed using a proprietary algorithm to quantify the slurry’ s mixture conditions based on measured values.