CN110208711A - Method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process - Google Patents

Abstract

The invention discloses a method for on-line detection of the pressure on the internal pole piece of a cylindrical battery during the charge-discharge cycle process. During the winding process of the cylindrical battery pole group, an insulation is installed inside and does not participate in the internal chemical reaction of the battery. A pressure sensor composed of materials, the insulated output wire connected to the pressure sensor is connected to the outside of the battery and connected to a data collection system for online collection of pressure data, which is used to monitor online the pressure of the pole pieces at different diameters inside the cylindrical battery during the battery charge and discharge cycle. and collect data for subsequent analysis. The invention can effectively monitor the force change of the pole piece in the pole group inside the battery through the pressure signal, so as to realize real-time on-line monitoring of the battery.

Description

Method for online testing of pole piece force during charging and discharging of cylindrical battery

technical field

The invention relates to the technical field of testing in battery production, in particular to a method for on-line testing of the stress on a pole piece during the charging and discharging process of a cylindrical battery.

Background technique

In recent years, lithium-ion batteries have been widely used in the electric vehicle market, and Tesla electric vehicles using cylindrical lithium-ion batteries occupy a large market share. Generally, household electric vehicle batteries need to meet the service life of 10-15 years, so the service life of batteries has attracted much attention. In addition to being related to the chemical system, the service life of the battery is inseparable from the structural design. Current research has found that the uneven force of the pole pieces inside the battery is one of the important factors that cause local lithium deposition and affect the battery cycle performance. During the cycle of lithium-ion batteries, since the pole piece will continue to expand with the increase in the number of charge and discharge, the extrusion force on the pole piece bound by the structure will gradually increase with the increase in the number of charge and discharge, while the cylindrical battery generally adopts a steel shell and the size Fixed, the center of the pole group is hollow design, the internal and external pressure of the pole group varies greatly, and this uneven force affects the cycle performance of the cell. In order to improve the pressure unevenness caused by the increase of charge and discharge times, it can be adjusted from the amount of space reserved in the winding tension of the electrode group and the structural design. All of the above improvements should be adjusted based on the pressure data of each pole piece in the pole group during the charging and discharging process of the battery. No method for this test has been reported yet.

Contents of the invention

The purpose of the present invention is to aim at the technical defects existing in the prior art, and to provide a method for online testing of the force of the pole pieces during the charging and discharging process of the cylindrical battery, especially a pressure between the pole pieces during the charging and discharging process of the battery. Changes in online monitoring methods.

The technical scheme adopted for realizing the purpose of the present invention is:

A method for online testing of the force on the pole piece during the charging and discharging process of a cylindrical battery is to install a pressure sensor inside the cylindrical battery pole group that is composed of insulating materials that do not participate in the chemical reaction inside the battery. , the insulated output wire connected to the pressure sensor is connected to the outside of the battery and connected to a data collection system that collects pressure data online, which is used to monitor the force of the pole pieces at different diameters inside the cylindrical battery online and collect data during the charge and discharge cycle of the battery. .

Preferably, the pressure sensor is a C-shaped ring structure.

Preferably, the pressure sensor includes an insulating hard substrate, a pressure-sensitive material coated on the insulating hard substrate and connected insulated output wires.

Among them, preferably, the thickness of the insulating hard substrate is 0.05-0.3mm, the barrel diameter is 0.3-20.3mm, the arc length at the C-shaped opening is 1-3mm, and the thickness of the pressure-sensitive material coating is 0.1-0.5mm.

Wherein, the pressure sensor is inserted at positions different from the center of the pole group of the battery and at different radii, and is in close contact with the surrounding pole pieces.

Preferably, when setting the pressure sensor, the cylindrical battery electrode group is first wound to the diameter of the position where the pressure needs to be tested, and then the pressure sensor is inserted through the gap into the diaphragm of the battery and continues to wind until the end of the winding.

Preferably, after the winding is completed, drill a hole on the explosion-proof aluminum plate of the battery cap, lead the insulated output wire connected to the pressure sensor out of the hole, inject liquid into the battery and seal it, and use superglue to block the insulated output wire out of the battery after sealing After the super glue is completely cured, the battery is charged. After normal aging, the battery is subjected to a charge-discharge cycle test according to the current required by the actual application, and the pressure data of the pole piece at the measured position is received simultaneously.

Preferably, the battery is first charged and discharged with a current less than 0.2C.

Compared with prior art, the beneficial effect of the present invention is:

In the present invention, the manufactured online testing device is placed in the pole group of the cylindrical battery, and the signal is transmitted to the outside of the sealed cylindrical battery through the transmission wire. During the normal charging and discharging process of the cylindrical battery, the internal pole of the battery is monitored through the pressure signal Changes in the force of the pole piece in the group.

Description of drawings

Fig. 1 is the schematic diagram of pressure sensor;

2 is a longitudinal sectional view of a circular battery including a pressure sensor;

Fig. 3 is a transverse cross-sectional view of a circular battery including a pressure sensor;

Fig. 4 is a schematic diagram of data collection of the pole piece pressure data collection system.

In the figure: 1. Hard insulating base material, 2. Pressure sensitive material, 3. Pressure sensor, 4. Battery pole group, 5. Battery shell, 6. Insulated output wire, 7. Battery cap.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figures 1-4, the method of the present invention for online testing of the stress on the pole piece during the charging and discharging process of a cylindrical battery is to use an insulating A notched ring-shaped pressure sensor 3 composed of substances that do not participate in the internal chemical reaction of the battery. The insulated output wire 6 (pressure sensor signal line) connected to the pressure sensor 3 is connected to the data collection system that collects pressure data online outside the battery. , which is used to monitor the force of the pole pieces at different diameters inside the cylindrical battery online during the charge-discharge cycle of the battery and collect data for subsequent analysis.

Preferably, the pressure sensor is a C-shaped ring structure, which is convenient for installation in the battery manufacturing process.

Preferably, the pressure sensor may include an insulating hard substrate 1 , a pressure-sensitive material 2 (pressure-sensitive material) coated on the inner side of the insulating hard substrate, and an insulated output wire 6 connected to the pressure-sensitive material.

Preferably, the thickness of the insulating hard substrate is 0.05-0.3mm, the diameter or barrel diameter is 0.3-20.3mm, the arc length at the C-shaped opening of the pressure sensor is 1-3mm, and the thickness of the pressure-sensitive material coating is 0.1-0.5mm.

Wherein, the pressure sensor 3 may be inserted at positions different from the center of the pole group of the battery and at different radii, and be in close contact with the surrounding pole pieces.

Wherein, in the present invention, the data collection system includes a data adopter and a data processing system, and the data collector is connected to the other end of the insulated output wire to transmit the adopted pressure data to the data processing system for further processing. Analysis, and then processed by the data processing system to output the test results.

Concrete preferred steps of the present invention are implemented as follows:

S101: First wind the cylindrical battery electrode group to the diameter of the position where the pressure needs to be tested, insert the C port of the C-type pressure sensor of the corresponding diameter into the diaphragm of the battery, and continue winding until the winding is completed.

S201: Drill a hole on the explosion-proof aluminum plate of the battery cap 7, lead out the insulated output wire 6 connected to the pressure sensor 3 from the drilled hole, inject liquid into the battery and seal it, and use superglue to block the insulated output wire out of the battery after sealing After the super glue is completely cured, charge the battery.

S301: Charge and discharge the battery for the first time with a current of less than 0.2C. After normal aging, the battery is subjected to a charge-discharge cycle test according to the current required by the actual application, and the pressure data of the pole piece at the measured position is received synchronously.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the protection scope of the present invention.

Claims (8)

1. a kind of method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process, which is characterized in that in circle In the group winding process of cylindrical cell pole, it is arranged internal using the material composition for insulating and being not involved in inside battery chemical reaction The insulation output lead of pressure sensor, pressure sensor connection connects the online data for collecting pressure data to outside batteries Collection system, for during battery carries out charge and discharge cycles, monitoring pole piece at the different-diameter of cylindrical battery inside on-line Stress condition simultaneously collects data.

2. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as described in claim 1, special Sign is that the pressure sensor is the cricoid structure of c-type.

3. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as claimed in claim 2, special Sign is that the pressure sensor includes insulating rigid substrate, coated on the insulating rigid substrate pressure sensitive and company The insulation output lead connect.

4. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as claimed in claim 3, special Sign is, the insulating rigid base material thickness is 0.05-0.3mm, bucket diameter 0.3-20.3mm, arc length 1- at c-opening 3mm, pressure sensitive coating layer thickness are 0.1-0.5mm.

5. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as described in claim 1, special Sign is that the pressure sensor is inserted at pole group center and different radii position away from battery, and close with pole piece around Contact.

6. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as described in claim 1, special Sign is, is that cylindrical battery pole group is first wound up into the diameter for needing to test pressure position, then when pressure sensor is arranged Continue to wind after pressure sensor is inserted into the diaphragm of battery by notch, until winding terminates.

7. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as claimed in claim 6, special Sign is, after winding, in the explosion-proof aluminium sheet upper drill hole of battery cap, will connect the insulation output lead of pressure sensor from It is drawn in hole, battery carries out fluid injection and seals, and battery blocks the hole that insulation output lead is drawn with seccotine after sealing, to strong Power glue charges the battery after thoroughly solidifying, and the electric current according to needed for practical application of the battery after normal aging carries out charge and discharge and follows Ring test, the synchronous pole piece pressure data for receiving measured position.

8. the method for pole piece stress condition in on-line testing cylindrical battery charge and discharge process as claimed in claim 7, special Sign is, with less than 0.2C current versus cell first charge-discharge.