[summary of the invention]
Based on this, be necessary to provide a kind of lithium battery sparking voltage of can finding out to there will be the battery electrochemical method of testing that first reduces rapidly rear rise phenomenon reason.
A kind of battery electrochemical method of testing, for the test of lithium battery chemical property, comprises the following steps:
Lithium battery is placed in container and draws battery positive and negative electrode;
In container, add electrolytic solution and draw the contrast electrode contacting with electrolytic solution;
Positive and negative electrode and more interelectrode change in voltage in electric discharge process.
In a preferred embodiment, in described electric discharge process, the step of the change in voltage between positive and negative electrode and contrast electrode comprises:
Test voltage lithium battery is with the situation of change of discharge current.
In addition, also provide a kind of battery electrochemical proving installation.
A kind of battery electrochemical proving installation, for the test of lithium battery chemical property, comprising:
Contrast electrode assembly;
Container, the passage that there is the cavity volume of perforation and communicate with described cavity volume, described cavity volume is used for accommodating lithium battery to be detected, and described passage is used for arranging described contrast electrode assembly, adds and holds electrolytic solution; And
Positive electrode assembly and negative electrode assembly, be arranged at the two ends of described cavity volume, for sealing described cavity volume and drawing the positive and negative electrode of lithium battery to be detected.
In a preferred embodiment, also comprise battery overcoat, described battery overcoat is for sheathed lithium battery to be measured and be installed on described cavity volume; The external diameter of described battery overcoat is less than the internal diameter of described cavity volume and is greater than the external diameter of lithium battery to be detected; Described battery overcoat offers through hole, and described through hole is for communicating with described passage, and the internal diameter of described through hole equals the internal diameter of described passage.
In a preferred embodiment, described contrast electrode assembly comprises contrast electrode post, electrolysis post and contrast electrode fixed block, described contrast electrode post and electrolysis post are and comprise the T-shaped of cap portion and bar portion, heavy stand hole is offered at the middle part of described contrast electrode fixed block, described heavy stand hole comprises platform part, described contrast electrode post is installed on described heavy stand hole, and the bar portion of described contrast electrode post extends outside described heavy stand hole, and cap portion is carried on described platform part; The cap portion end face of the cap portion end face of described electrolysis post and described contrast electrode post is close to, and bar portion extends to described passage.
In a preferred embodiment, the entrance of described passage is passage heavy stand, and described passage heavy stand is used for carrying described electrolysis post, between the cap portion of described electrolysis post and described passage heavy stand, uses channel seal circle to seal.
In a preferred embodiment, described passage heavy stand is also for installing electrolysis post dead ring, and the cap portion that described electrolysis post dead ring is sheathed on described electrolysis post is along week, for described electrolysis post and the described container of insulating.
In a preferred embodiment, described positive electrode assembly comprises positive electricity pole, positive electrode fixed block and positive electrode compression bar, described positive electricity pole is comprise cap portion and bar portion T-shaped, shoulder hole is offered at the middle part of described positive electrode fixed block, described shoulder hole comprises stage portion, described positive electricity pole is installed on described shoulder hole, and the bar portion of described positive electricity pole extends outside described shoulder hole, and cap portion is carried on described stage portion; Described positive electrode compression bar is installed on the cap portion end face of described positive electricity pole.
In a preferred embodiment, described negative electrode assembly comprises negative electricity pole, negative electrode fixed block and negative electrode compression bar, described negative electricity pole is identical with the structure of the positive electricity pole in described positive electrode assembly, negative electrode fixed block is identical with the structure of the positive electrode fixed block in positive electrode assembly, and described negative electrode compression bar is identical with the structure of the positive electrode compression bar in positive electrode assembly.
In a preferred embodiment, the two ends of described cavity volume are provided with cavity volume heavy stand, the cavity volume heavy stand at two ends is used for carrying positive electricity pole, negative electricity pole and installing electrodes dead ring, between the cap portion of positive electricity pole and negative electricity pole and the cavity volume heavy stand at two ends, use cavity volume O-ring seal to seal, electrode insulation ring set is located at the cap portion of positive electricity pole and negative electricity pole along week, keeps insulation for making between positive electricity pole and container, between negative electricity pole and container.
Above-mentioned battery electrochemical method of testing and device, in lithium battery discharge process, first detect voltage between the lithium battery positive and negative electrode situation of change with discharge current, then detect contrast electrode with between positive electrode, contrast electrode is with the situation of change of voltage between negative electrode, above change in voltage situation is compared, can find out lithium battery sparking voltage and occur that first the problem of the rear rise phenomenon of reduction is positive pole or the negative pole in lithium battery rapidly, eliminate the method for this kind of phenomenon for finding out and prepare.
[embodiment]
In order to find out lithium battery in the time that discharge current is enough large, the reason of the phenomenon rising after first reducing rapidly appears in sparking voltage, provides the one can battery electrochemical method of testing and device.
As shown in Figure 1, the battery electrochemical method of testing of preferred embodiment, comprises the following steps:
Step S110, lithium battery is placed in container and draws battery positive and negative electrode.Lithium battery is inserted in container, be fixed by the two poles of the earth that compress lithium battery, two electrodes are drawn beyond container by good conductor, so that test.
Step S120 adds electrolytic solution and draws the contrast electrode contacting with electrolytic solution in container.In container, add electrolytic solution and contrast electrode is set, one end of contrast electrode is stretched in electrolytic solution, and the other end is drawn beyond container.This contrast electrode has constant voltage, for the reference electrode as weighing electrode to be detected.Airtight container, makes in lithium battery and the electrolytic solution space in sealing.
Step S130, the change in voltage between any two in positive and negative electrode and contrast electrode when electric discharge.By the good conductor of drawing, lithium battery is accessed to load, by the voltage situation over time between instrument test positive pole and negative pole, between positive pole and contrast electrode, between negative pole and contrast electrode, the line item of going forward side by side.Compare discovery according to test result, in the time that the voltage between positive pole and negative pole occurs first declining the phenomenon raising afterwards, between positive pole and contrast electrode or between negative pole and contrast electrode, surely have one group of phenomenon raising after there will be pressure-wire to decline.
In the present embodiment, step S130 comprises the situation of change of test voltage with lithium battery discharge current.Under normal circumstances, in the time that discharge current acquires a certain degree, the voltage between positive and negative electrode just there will be the phenomenon that first declines and raise afterwards.When test, the voltage of first finding out between positive and negative electrode just there will be discharge current corresponding to phenomenon that first declines and raise afterwards, and then for change in voltage situation between this testing current positive pole and contrast electrode or between negative pole and contrast electrode.
Above-mentioned battery electrochemical method of testing, in lithium battery discharge process, first detect voltage between the positive and negative electrode situation of change with discharge current, then detect contrast electrode with between positive electrode, contrast electrode is with the situation of change of voltage between negative electrode, above change in voltage situation is compared, can find out lithium battery sparking voltage and occur that first the problem of the rear rise phenomenon of reduction is positive pole or the negative pole in lithium battery rapidly.
As shown in Figure 2, Figure 3 and Figure 4, the battery electrochemical proving installation of preferred embodiment, comprises container 110, contrast electrode assembly 120, positive electrode assembly 130 and negative electrode assembly 140.The passage 114 that container 110 has the cavity volume 112 of perforation and communicates with described cavity volume 112, cavity volume 112 is for accommodating lithium battery to be detected, and passage 114 is for arranging contrast electrode assembly 120, add and hold electrolytic solution.Positive electrode assembly 130 and negative electrode assembly 140 are arranged at the two ends of cavity volume 112, for sealed volume 112 and draw positive pole and the negative pole of lithium battery to be detected.Contrast electrode assembly 120, positive electrode assembly 130 and negative electrode assembly 140 use bolt to be fixed on container 110 conventionally.While using this device, lithium battery is packed in cavity volume 112, the two ends of cavity volume 112 are used positive electrode assembly 130 and negative electrode assembly 140 to encapsulate, and make positive electrode assembly 130 keep good with the positive pole of lithium battery with negative pole respectively with negative electrode assembly 140 to contact, to draw the both positive and negative polarity of lithium battery, be convenient to wiring.Pull down contrast electrode assembly 120, be added into appropriate electrolytic solution to passage, contrast electrode assembly 120 is re-installed in to the porch of passage 114 and keeps sealing.The amount of adding electrolytic solution must cover one end of contrast electrode assembly 120, to guarantee the generation of electrolytic reaction, for contrast electrode assembly 120 provides stable electromotive force.
Above-mentioned battery electrochemical proving installation, in lithium battery discharge process, first detect voltage between positive electrode assembly 130 and negative electrode assembly 140 situation of change with discharge current, then detect contrast electrode assembly 120 with between positive electrode assembly 130, contrast electrode assembly 120 with voltage between negative electrode assembly 140 with the situation of change of discharge current, above change in voltage situation is compared, can find out lithium battery sparking voltage and occur that first the problem of the rear rise phenomenon of reduction is positive pole or the negative pole in lithium battery rapidly, eliminate the method for this kind of phenomenon prepares for finding out.
In the present embodiment, battery electrochemical proving installation also comprises battery overcoat 150.Battery overcoat 150 is for sheathed lithium battery to be measured and be installed on cavity volume 112.The external diameter of battery overcoat 150 is less than the internal diameter of cavity volume 112 and is greater than the external diameter of lithium battery to be detected.Specifically, in test process, due to the specification difference of lithium battery, external diameter difference, therefore needs the different battery overcoat of internal diameter corresponding with the specification of lithium battery.If when the external diameter of lithium battery is slightly less than the internal diameter of cavity volume 112, just without using battery overcoat.Battery overcoat 150 offers through hole, and through hole is for communicating with passage 114, and the internal diameter of through hole equals the internal diameter of passage 114.
In the present embodiment, contrast electrode assembly comprises contrast electrode post 122, electrolysis post 124 and contrast electrode fixed block 126.It is material that contrast electrode 122, electrolysis post 124 and contrast electrode fixed block 126 adopt respectively brass, silver and bakelite.Contrast electrode post 122 and electrolysis post 124 are T-shaped, comprise cap portion and bar portion.Heavy stand hole 1261 is offered at the middle part of contrast electrode fixed block 126, and described heavy stand hole comprises platform part 1263.Contrast electrode post 122 is installed on heavy stand hole 1261.The bar portion of contrast electrode post 122 extends outside described heavy stand hole, and cap portion is carried on platform part 1263.The cap portion end face of the cap portion end face of electrolysis post 124 and contrast electrode post 122 is close to, and bar portion extends to passage 114.
In the present embodiment, the entrance of passage 114 is heavy stand 1141.Heavy stand 1141 is for carrying electrolysis post 124.Between the cap portion of electrolysis post 124 and heavy stand 1141, use channel seal circle 160 to seal, so that in the space of electrolytic solution in sealing, avoid contacting with outside air.
In the present embodiment, heavy stand 1141 is also for installing electrolysis post dead ring 170.Electrolysis post dead ring 170 is sheathed on the cap portion of described electrolysis post 124 along week, for insulation electrolytic post 124 and container 110.
In the present embodiment, positive electrode assembly 130 comprises positive electricity pole 132, positive electrode fixed block 134 and positive electrode compression bar.Positive electricity pole 132 is T-shaped, comprises cap portion and bar portion.Shoulder hole is offered at the middle part of positive electrode fixed block 134, and shoulder hole comprises stage portion, and positive electricity pole 132 is installed on shoulder hole, and the bar portion of positive electricity pole 132 extends outside shoulder hole, and cap portion is carried on stage portion.Positive electrode compression bar 136 adopts brass to make, and conventionally uses bolt to be installed on the cap portion end face of positive electricity pole 132, so that lithium battery is while packing cavity volume 112 into, and positive electrode compression bar 136 and electrode of lithium cell good contact.
In the present embodiment, negative electrode assembly 140 comprises negative electricity pole 142, negative electrode fixed block 144 and negative electrode compression bar 146.Negative electricity pole 142 is identical with the structure of the positive electricity pole 132 in positive electrode assembly 130, negative electrode fixed block 144 is identical with the structure of the positive electrode fixed block 134 in positive electrode assembly 130, and negative electrode compression bar 146 is identical with the structure of the positive electrode compression bar 136 in positive electrode assembly 130.
In the present embodiment, the two ends of cavity volume 112 are provided with cavity volume heavy stand 1121.The cavity volume heavy stand 1121 at two ends is for carrying positive electricity pole 132, negative electricity pole 142 and installing electrodes dead ring 180.Between the cavity volume heavy stand 1121 at the cap portion of positive electricity pole 132 and negative electricity pole 142 and cavity volume 112 two ends, use cavity volume O-ring seal 190 to seal.Electrode insulation ring 180 is sheathed on the cap portion of positive electricity pole 132 and negative electricity pole 142 along week, keeps insulation for making between positive electricity pole 132 and container 110, between negative electricity pole 142 and container 110.
Be that 18650-1Ah high power lithium battery is set forth below in conjunction with model.
Multiplying power discharging curve between the lithium battery both positive and negative polarity while as shown in Figure 4, being respectively 10A, 20A, 30A and 40A for discharge current.From this curve, in the time that discharge current is 40A, voltage has the phenomenon that first reduction raises again rapidly.
In order to analyze the reason of this phenomenon, adopt battery electrochemical proving installation of the present invention to test.By lithium battery embedded device cavity volume to be measured, after device assembling is ready, between positive electrode assembly and negative electrode assembly, access load, when testing respectively lithium battery discharge current and being respectively 10A, 20A, 30A and 40A, the change in voltage situation between positive electrode assembly and contrast electrode assembly, between negative electrode assembly and contrast electrode assembly.
The multiplying power discharging curve of the lithium battery contrast electrode while as shown in Figure 5, being respectively 10A, 20A, 30A and 40A for discharge current and positive interpolar.From curve, in the time that discharge current is 40A, voltage has the phenomenon that first reduction raises again rapidly.
Multiplying power discharging curve between lithium battery contrast electrode and negative pole while as shown in Figure 6, being respectively 10A, 20A, 30A and 40A for discharge current.From curve, in the time that discharge current is 40A, voltage is without first reducing rapidly the phenomenon raising again.
Have above-mentioned experimental result known, when discharge current is 40A, voltage first declines and raises and caused by lithium battery anode afterwards.Draw and change after conclusion, just can improve for the positive pole of lithium battery.
The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.