In the performance puzzle of lithium-ion batteries, the pole piece is the cornerstone that carries energy and power. The quality of its conductivity directly determines the internal resistance of the battery, the stability of the voltage platform, and the speed of self discharge. More profoundly, the conductivity of the electrode is like a mirror, which can reflect the uniformity of its internal microstructure - from the bonding interface between the current collector and the active coating, to the three-dimensional distribution network of the conductive agent, and to the tight contact state between particles - these invisible microscopic worlds together define the boundary of the final performance of the battery.

However, for a long time, our tools for insight into this microscopic world have had limitations. The traditional four probe and two probe methods, like fingertips that can only touch the surface of an object, have two fundamental "blind spots": firstly, they cannot simulate the pressure environment that batteries are subjected to in actual manufacturing (such as rolling) and working conditions, and the measurement is carried out in a non real "relaxed" state; Secondly, they can only detect the resistance information of thin layers on the surface of the polarizer. For thick coatings composed of countless particles stacked together and possibly with compositional gradients, these methods cannot perceive the overall coating or measure the crucial 'interface contact resistance' between the coating and the metal substrate. When the active particles of the polarizer are large, the accidental contact between the probe and the particles causes significant fluctuations in the measurement data, and the reference significance is limited.

To truly see through the conductive nature of the polarizer, we have developed a revolutionaryMulti functional polarizer resistance measurement systemThis system is no longer satisfied with surface and static measurements, but actively intervenes by simulating real working conditions to excite and observe the complete electrical response of the polarizer.

Core breakthrough: Apply pressure to activate multidimensional representation

The design philosophy of this system is to introduce a key variable:Controllable and accurately measurable pressureWe believe that only under pressure will the microstructure of the polarizer reveal the truth.

The system can apply a variable pressure to the polarizer from gentle to significant during the testing process, and synchronously and instantly collect three core data streams:The applied pressure value, real-time resistance value of the pole piece, and the change in pole piece thickness due to compressionThrough the correlation of these three factors, we are able to construct a clear experimental framework“Pressure deformation resistance”The dynamic relationship model among the three.

Innovation in measurement principles: from surface to bulk, from static to dynamic

Unlike the probe method which only scratches the surface, the current path design of this system isVertically pass through the end face of the polarizerThis means that the current will flow through the entire thickness direction of the coating, inevitably crossing the bonding interface between the coating and the substrate, thus measuring the resistance including bulk resistance and interface contact resistanceOverall resistanceThis measurement method is the key to overcoming the difficulties of measuring thick coatings and interface resistance.

When different sizes of pressure are applied to the surface of the polarizer, a series of physical changes occur in the particle world of the coating: the particles undergo elastic or plastic deformation, the contact points between each other increase, the contact area expands, and the conductive network is reconstructed or even optimized. By observing the variation curves of resistance values under different pressures, we can accurately analyze:

• The structural stability of polar conductive networks.

• The degree of adhesion between the coating and the substrate.

• The pressure range corresponding to the conductive state provides a direct reference for the rolling process.

• The performance differences of electrode sheets under pressure with different formulations (such as types and contents of conductive agents).

From Data to Insights: Empowering R&D and Quality Control

This system provides far more than just a resistance number, but a "characteristic map" that reflects the inherent quality of the polarizer.

• For R&D personnelIt is a microscope for optimizing formulas and processes. By comparing the pressure resistance curves of different samples, it is possible to scientifically evaluate the dispersion effect of conductive agents and the rationality of the binder system, and quickly screen out the electrode plate scheme for the structure.

• For quality controlIt is a precise 'ruler'. A characteristic curve of standard samples can be established to quickly determine the consistency of production batches and promptly detect potential defects such as coating looseness and poor contact.

• For performance predictionIt is a reliable 'bridge'. The uniformity and variation trend of the resistance of the polarizer under compression are related to the final rate performance and cycle life of the battery, providing a new and reliable basis for the pre judgment of battery performance.

Conclusion

The traditional method of measuring electrode resistance is like touching an elephant in the dark, and can only perceive the local area. And the multifunctional electrode resistance measurement system we bring lights up, allowing you to observe and even interact with it by applying pressure, truly understanding the structure and strength of this' elephant '.

It is not just an instrument, but also a new concept of polar representation——To achieve a complete and dynamic evaluation of the electrical conductivity between the polarizer body phase and the interface under simulated real stress conditionsThis marks a crucial step in the transition of battery electrode detection from two-dimensional surfaces to three-dimensional bulk phases, and from static properties to dynamic responses. The aim is to provide a solid data foundation from micro mechanisms to macro processes for improving battery performance, driving battery technology to a higher level.