Evaluating the Adhesive Strength between Electrode Sheets and Current Collectors
Special Feature on Lithium-Ion Battery Testing, Evaluation, and Jigs
Considering that lithium-ion batteries are assembled from a variety of materials, such as ceramics, polymers, and electrolyte solutions, and they involve electrochemical changes that occur due to charge-discharge cycles, manufacturing processes are controlled to ensure they are manufactured according to design. This requires many evaluations to be performed to ensure their performance satisfies capacity, safety, and other specification requirements. Testing machines, in combination with various testing jigs, can be used for a wide variety of these evaluations.
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Evaluating the Tensile Strength of Current Collectors
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Evaluating the Piercing/Penetration Strength of Separators
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Evaluating the Density of Active Materials
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Evaluating the Strength of Cell Cases
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Evaluating Electrode Sheet Bending Elastic Modulus
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Evaluating the Battery Cell Status during the Charge-Discharge Cycle
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Evaluating the Pressure Capacity of Battery Cells
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Evaluating Batteries with Atmospheric Control
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Measuring the Strength of Individual Particles in Battery Materials
Evaluating the Adhesive Strength between Electrode Sheets and Current Collectors
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Electrode sheets are adhered tightly to current collectors by a binder. The electrons generated by lithium-ion movement pass through the current collector and are removed from the battery cell. The adhesive strength between electrode sheets and current collectors is evaluated to improve battery performance and for manufacturing process control.
Using this jig, table movements can be linked to testing machine movements to ensure peeling tests are performed with the peeling angle maintained at 90 degrees. Similarly, 180-degree peel, T-peel, and other tests can be performed using appropriate jigs.
Evaluating the Tensile Strength of Current Collectors
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To increase the coating quantity on electrode sheets, current collectors are perforated or made with a metal-coated polymer material. Electrode sheets are manufactured using a roll-to-roll method that applies tension during manufacturing. Therefore, tensile strength is evaluated.
This high-performance jig reduces grip face swiveling and features a special grip face shape that reduces breakage at the chuck when testing foils. It is ideal for tensile testing copper and aluminum foils used for current collectors. Similarly, separators, electrode sheets, and other materials can be measured by using appropriate jigs.
Evaluating the Piercing/Penetration Strength of Separators
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After repeatedly charging and discharging batteries, metal precipitates can form inside them. If metal precipitate material passes through a separator, it can cause a fire due to short-circuiting. Therefore, the piercing/penetration strength of separators is evaluated.
This jig is designed with a simple nut-based fixing method, allowing for easy installation and removal of separators and superior operability.
Evaluating the Density of Active Materials
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Electrode materials are processed with a pressing treatment during manufacturing in order to increase density, but variations in the pressing force can cause variability in battery performance. Furthermore, because electrode materials are rolled or stacked into multiple layers after pressing, even slight differences in electrode thickness can potentially cause the size of the rolled or stacked layers to not fit within the specified design dimensions. Therefore, density is evaluated with pressure applied to the powder.
The simple structure of this jig, consisting of only a case and plunger, makes it easy to remove samples and clean the case after measurements.
Evaluating the Strength of Cell Cases
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Battery cell cases are manufactured by welding or other joining technologies. Joint defects can cause leaking, electrical contact faults, and other problems to the battery cells. Therefore, the strength of cell cases is evaluated.
This jig is open toward the front, which makes it easier to insert samples or replace grip faces. The wedging action holds samples securely between grip faces and minimizes sample slippage during tests. 
Evaluating Electrode Sheet Bending Elastic Modulus
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Electrode sheets are fabricated based on the cell case, with electrode membrane thickness increasing in recent years due to the increasing capacities of lithium-ion batteries. Typically, increasing membrane thickness increases the hardness, which increases elongation at the outer perimeter during the bending process. That can cause cracking and other problems. Therefore, the elasticity of electrode sheets is evaluated.
A wide variety of bending jigs are available with various punch and support configurations for different sample shapes and sizes. It is also easy to adjust the span distance between supports. 
Evaluating the Battery Cell Status during the Charge-Discharge Cycle
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Batteries expand and contract during charge-discharge cycles due to intercalation of lithium ions. Therefore, battery modules are designed to withstand a certain amount of confining pressure. Consequently, they must be evaluated with applied loads equivalent to those experienced while installed in a vehicle. Battery performance is evaluated with the battery cell confined by a certain amount of pressure or to a certain dimension. In addition, dimensional changes are measured while the battery is exposed to a certain pressure.
This jig can accurately measure micro-displacements by using four displacement sensors installed on the compression plates to measure the distance between compression plates. Furthermore, the compression plate surfaces have a Rockwell hardness (HRC scale) of 60 to ensure smoothness and extremely low friction levels are maintained. 
Evaluating the Pressure Capacity of Battery Cells
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The activity level inside lithium-ion batteries is increased to achieve higher capacity and output. However, due to the high activity level, internal short circuits, external impacts, and other factors can result in abnormal conditions that might cause ignition or a fire. Therefore, the pressure capacity of battery cells is evaluated by a crushing test.
This system features an explosion-resistant testing space that ensures safety in the event a battery explodes and includes an anti-corrosion treatment to prevent corrosion by electrolyte solutions or other substances. It also can be used for battery nail penetration testing. 
Evaluating Batteries with Atmospheric Control
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All parts installed in automobiles must be evaluated in a temperature and humidity-controlled state. Because the operating environment of lithium-ion batteries can have a major effect on their performance and safety, it is essential to evaluate them in an environmentally controlled state. Therefore, they are evaluated with an atmospheric control unit attached to the testing machines used.
All sorts of strength tests, such as tension, compression, and peeling, are performed in an atmosphere that simulates the actual operating environment, with temperatures ranging from subfreezing to high temperature. 
Measuring the Strength of Individual Particles in Battery Materials
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Battery materials are constantly exposed to pressures during manufacturing processes or in operating environments, making it important to evaluate their mechanical properties for design, development, and quality control purposes.
MCT series micro compression testing machines use a compression plate to apply load to individual particles in order to measure the relationship between test force and compression displacement in real time. With an ability to measure particles as small as a few micrometers in diameter, they can be used to evaluate the strength of powdered materials used in lithium-ion batteries. Application examples include positive electrode materials, negative electrode materials, and solid electrolytes. 