Background technology
Lithium battery forms primarily of positive pole, negative pole, electrolytic solution and barrier film, its septation is between positive pole and negative pole, and effect is separated positive pole and negative pole, prevents electronics from passing through, but allow ion to pass through, when internal temperature of battery raises, battery diaphragm can close micropore, stops lithium ion to pass through, cut off contacting between positive pole and negative pole, cell reaction is stopped, and improve the security of battery, therefore the security of performance to battery of lithium battery diaphragm plays vital effect.
Because the structure of barrier film is made up of a large amount of micropores, intercommunication each other, pore size is the film of less than 1 μm, security is the safety index that first battery is considered, particularly relate to electrokinetic cell field, the heat produced due to internal short-circuit of battery makes internal temperature of battery raise rapidly, when temperature is elevated to a certain degree, diaphragm micro-hole slowly can close along with the rising of temperature, battery internal resistance is increased, until diaphragm micro-hole structure is completely closed, now inside battery both positive and negative polarity reacts completely stopping, internal temperature of battery is controlled, prevent the generation of " thermal runaway " phenomenon, lithium battery is effectively prevented to explode or the generation of the security incident such as on fire, this temperature value is lower, lithium battery closes the time of inside battery reaction more in a short-circuit situation, lithium battery is safer, otherwise, battery security is difficult to be protected, but this temperature must at proper range, the environment temperature that simultaneously should use higher than battery, to ensure that battery normally uses, this temperature is exactly closed pore temperature, decide the security performance of battery, if the heat that the chemical reaction of inside battery produces has little time to shed, after micropore closed by barrier film, temperature continues to rise, reach the melt temperature of diaphragm material, cause membrane ruptures, inside battery positive/negative plate is in direct contact with together, there is violent chemical reaction, internal temperature raises rapidly again, cause the generation of " thermal runaway ", battery catches fire is caused to explode time serious, so temperature during membrane ruptures is also an important indicator of lithium battery security, this temperature is exactly broken film temperature, therefore weigh from lithium battery security standpoint, closed pore, broken film temperature is an important indicator that must control in battery diaphragm production run, vital effect is played to the security of lithium battery, so, closed pore, the research of the method for testing of broken film temperature especially proving installation is absolutely necessary to lithium battery diaphragm quality control.
At present, most of lithium battery diaphragm manufacturer does not provide temperature range and the correlation parameter of the relation cell safety such as closed pore, rupture of membranes of separator product, also be very different between lithium battery diaphragm product, and using manufacturer can not to measure accurately the closed pore of barrier film, broken film temperature at present, this uses user to exist a serious potential safety hazard during lithium battery product.
Utility model content
For overcoming above-mentioned shortcoming, the utility model provides a kind of energy Accurate Determining diaphragm closed pore, the diaphragm closed pore of broken film temperature, broken film temperature proving installation.
The purpose of this utility model is achieved through the following technical measures, a kind of diaphragm closed pore, broken film temperature proving installation, comprise circular shaped tiles and circular bottom plate, described circular bottom plate is provided with the base plate reservoir for storing electrolytic solution towards the center of the one side of circular shaped tiles, barrier film to be measured is coated with above described reservoir, described diaphragm to be measured is covered with a grommet type seals, circular shaped tiles is covered with above described O-ring seal, the center of circular shaped tiles is provided with one for storing the mainboard liquid storage cylinder of electrolytic solution, described mainboard liquid storage cylinder is through hole, described mainboard liquid storage cylinder upper surface is covered with seal gasket successively, cover plate and activity bar, described circular shaped tiles and circular bottom plate are provided with multiple fixed orifice with one heart, and at least two pairs of fixed orifices are equipped with screw rod, and described screw rod extends circular shaped tiles surface and connected by nut after sheathed spring, be provided with threaded hole in the middle of described activity bar, a center bolt compresses on the cover board through threaded hole, and described activity bar is fixed on circular shaped tiles, be electrically insulated between described circular shaped tiles and circular bottom plate, described circular shaped tiles and circular bottom plate are electrically connected the two poles of the earth of internal resistance instrument respectively.
As a kind of optimal way, described activity bar two end is provided with two through holes, described circular shaped tiles and circular bottom plate are respectively arranged with the fixed orifice concentric with through hole, described screw rod is connected by a nut through after the fixed orifice of circular bottom plate and circular shaped tiles and through hole successively, and described activity bar is floating above circular shaped tiles.
As a kind of optimal way, described circular bottom plate is provided with the thermometer hole of a placement thermocouple probe.
As a kind of optimal way, described screw rod is by the fixed orifice of insulating mat through circular bottom plate.
As a kind of optimal way, described circular shaped tiles and circular bottom plate are all corrosion resistant plate.
Spring of the present utility model plays a good regulating action, and when O-ring seal expanded by heating, spring, according to device air pressure inside change automatic telescopic, avoids deformation gas leakage or the leakage greatly of O-ring seal stress, causes test crash; Proving installation base plate center is provided with a reservoir, during test wet method barrier film be put in fill electrolytic solution reservoir on, expansion base plate hindering hole after rupture of membranes is sticked to after avoiding the melting of test process septation, after solving barrier film rupture of membranes, proving installation resistance fall off rate is slow, there is no obvious flex point, be difficult to the puzzlement distinguishing broken film temperature, improve the degree of accuracy of test; The design that the utility model adopts, greatly shortens the test duration on heating rate advantageously, improves work efficiency; The utility model simple and convenient assembly, test result reappearance and consistance better.
Embodiment
Contrast accompanying drawing below in conjunction with embodiment the utility model is described in further detail.
A kind of diaphragm closed pore, broken film temperature proving installation, please refer to Fig. 1 and Fig. 2, comprise circular shaped tiles 5 and circular bottom plate 8, described circular bottom plate 8 is provided with the base plate reservoir 801 for storing electrolytic solution towards the center of the one side of circular shaped tiles 5, barrier film 7 to be measured is coated with above described reservoir 801, a grommet type seals 6 is covered with above described barrier film to be measured 7, circular shaped tiles 5 is covered with above described O-ring seal 6, the center of circular shaped tiles 5 is provided with one for storing the mainboard liquid storage cylinder 501 of electrolytic solution, described mainboard liquid storage cylinder 501 is through hole, described mainboard liquid storage cylinder 501 upper surface is covered with seal gasket 11 successively, cover plate 10 and activity bar 3, described circular shaped tiles 5 and circular bottom plate 8 are provided with multiple fixed orifice with one heart, and at least two pairs of fixed orifices are equipped with screw rod 9, and described screw rod 9 extends circular shaped tiles 5 surface and connected by nut 2 after sheathed spring 4, be provided with threaded hole in the middle of described activity bar 3, a center bolt 1 is pressed on cover plate 10 through threaded hole, and described activity bar 3 is fixed on circular shaped tiles 5, be electrically insulated between described circular shaped tiles 5 and circular bottom plate 8, described circular shaped tiles 5 and circular bottom plate 8 are electrically connected the two poles of the earth of internal resistance instrument respectively.
During test, after filling electrolytic solution in base plate reservoir 801, barrier film 7 is placed on base plate reservoir 801, it is outer and be placed between circular shaped tiles 5 and circular bottom plate 8 that O-ring seal 6 is set in base plate reservoir 801, thus prevent electrolytic solution and be electrically insulated circular shaped tiles 5 and circular bottom plate 8, by the fixed orifice of screw rod 9 through circular bottom plate 8, fastening with nut 2 after penetrating buffer spring 4, after filling electrolytic solution by mainboard liquid storage cylinder 501, be screwed after placing seal gasket 11, cover plate 10, activity bar 3 in order.
Lithium ion battery separator is a kind of many micropores high molecular film material, at ambient temperature, lithium ion energy free shuttling is in diaphragm micro-hole, the internal resistance of cell is less, the charge and discharge process of Here it is lithium battery, but after environment temperature improves, micropore is slowly heated swelling reducing, when reaching uniform temperature (Tb), micropore is closed completely, lithium ion cannot be shuttled back and forth by diaphragm micro-hole, internal resistance increases rapidly, open circuit is formed between both positive and negative polarity, if temperature continues to rise, rise to uniform temperature (Tp), diaphragm material melting, diaphragm retracts, break and define cavity, lithium ion shuttles back and forth again between both positive and negative polarity, internal resistance reduces rapidly, Tb is exactly the closed pore temperature of barrier film, and Tp is broken film temperature, therefore, just the closed pore of barrier film directly can be calculated by the change of measuring the internal resistance of lithium battery temperature-rise period, broken film temperature.
Utilize this device to carry out diaphragm closed pore, broken film temperature detection method, comprise following step:
[1] open baking oven power supply, arranging oven temperature is 180 DEG C, preheating oven;
[2] assemble battery septum closed pore temperature, broken film temperature proving installation: the assembled in sequence of pressing base, barrier film to be measured, O-ring seal, mainboard, fix with bolt and nut;
[3] about 1 ~ 2ml electrolytic solution is got with syringe, inject proving installation from mainboard liquid storage cylinder 501, with hand, device is vibrated gently on table top, the air in device is discharged, add electrolytic solution to be full of to aperture, then the O-ring seal of device and upper cover are pressed fixing;
[4] the thermometric line of temperature measuring set is put in baking oven from the aperture at baking oven top, the thermometer hole of temperature measuring head insertion apparatus;
[5] two of internal resistance instrument downhole joints are put in baking oven from the aperture at baking oven top, be connected with the electrode site on the mainboard of device and base plate respectively;
[6] the inner walkway device assembled is put on the cardboard of baking oven, note preventing the two poles of the earth short circuit;
[7] open internal resistance instrument power supply, the measurement range ability of internal resistance instrument is set;
[8] power supply of open temp registering instrument;
[9] displayed value of internal resistance instrument and moisture recorder is recorded respectively;
1. when module temperature be increased to close on closed pore temperature (Tb) time, internal resistance value can increase rapidly, and internal resistance value exceedes the range ability that internal resistance instrument is measured, and instrument sounds the alarm;
2., after temperature rises to over broken film temperature (Tp), internal resistance value can reduce rapidly again and is returned to internal resistance instrument measurement range;
[10] after having surveyed broken film temperature, close the power supply of internal resistance instrument, moisture recorder, remove the line of inner walkway module, take out inner walkway module;
[11] clean up inner walkway module, change another sample, repeat to test again once as stated above;
When the Tb difference of [12] twice test is more than 3 DEG C, need again to detect once as stated above again;
[13], after having tested, the setting of the temperature of baking oven is turned down, does not stop fan blower and make oven temperature be reduced to less than 100 DEG C, close baking oven power supply;
[14] dismantle inner walkway module, modular unit is cleaned up.
The spring of this device plays a good regulating action, and when O-ring seal expanded by heating, spring, according to device air pressure inside change automatic telescopic, avoids deformation gas leakage or the leakage greatly of O-ring seal stress, causes test crash; Proving installation base plate center is provided with a reservoir, during test wet method barrier film be put in fill electrolytic solution reservoir on, expansion base plate hindering hole after rupture of membranes is sticked to after avoiding the melting of test process septation, after solving barrier film rupture of membranes, proving installation resistance fall off rate is slow, there is no obvious flex point, be difficult to the puzzlement distinguishing broken film temperature, improve the degree of accuracy of test; The design that this device adopts, greatly shortens the test duration on heating rate advantageously, improves work efficiency; This proving installation simple and convenient assembly, test result reappearance and consistance better.
In the diaphragm closed pore, broken film temperature proving installation of an embodiment, please refer to Fig. 1 and Fig. 2, the basis of previous technique scheme can also be specifically, activity bar 3 two end is provided with two through holes, described circular shaped tiles 5 and circular bottom plate 8 are respectively arranged with the fixed orifice concentric with through hole, described screw rod 9 is connected by a nut 2 through after the fixed orifice of circular bottom plate 8 and circular shaped tiles 5 and through hole successively, described activity bar 3 is floating to be fixed on above circular shaped tiles 5, thus when O-ring seal expanded by heating, circular shaped tiles 5 can drive activity bar 3 synchronously to move up.
In the diaphragm closed pore, broken film temperature proving installation of an embodiment, please refer to Fig. 1 and Fig. 2, the basis of previous technique scheme can also be specifically, circular bottom plate 8 is provided with the thermometer hole 802 of a placement thermocouple probe.
In the diaphragm closed pore, broken film temperature proving installation of an embodiment, please refer to Fig. 2, the basis of previous technique scheme can also be specifically, screw rod 9 is by the fixed orifice of insulating mat 901 through circular bottom plate 8.
In the diaphragm closed pore, broken film temperature proving installation of an embodiment, the basis of previous technique scheme can also be specifically that circular shaped tiles 5 and circular bottom plate 8 are all corrosion resistant plate.
More than that the utility model diaphragm closed pore, broken film temperature proving installation are set forth; the utility model is understood for helping; but embodiment of the present utility model is not restricted to the described embodiments; any do not deviate from the utility model principle under do change, modification, substitute, combination, simplify; all should be the substitute mode of equivalence, be included within protection domain of the present utility model.