阅读说明：本技术 极耳、电池电芯及虚焊识别方法 (Tab, battery cell and rosin joint identification method ) 是由 黄官亮 李扬 王岩 张红 余肖维 谢继春 于 2020-12-29 设计创作，主要内容包括：本申请公开了一种极耳、电池电芯及虚焊识别方法,属于电池技术领域。该极耳包括：导电层和负温度系数NTC电阻层,所述NTC电阻层设于所述导电层上,且所述NTC电阻层的电阻值与温度负相关。这样可以实现对电池电芯的极耳和集流体的焊接效果的检测,并降低了电池电芯的极耳和集流体的焊接效果的检测难度。(The application discloses a tab, a battery cell and a rosin joint identification method, and belongs to the technical field of batteries. This utmost point ear includes: the temperature-sensitive resistor comprises a conducting layer and a Negative Temperature Coefficient (NTC) resistor layer, wherein the NTC resistor layer is arranged on the conducting layer, and the resistance value of the NTC resistor layer is inversely related to the temperature. Therefore, the detection of the welding effect of the lug of the battery cell and the current collector can be realized, and the detection difficulty of the welding effect of the lug of the battery cell and the current collector is reduced.)

1. A tab, comprising: the temperature-sensitive resistor comprises a conducting layer and a Negative Temperature Coefficient (NTC) resistor layer, wherein the NTC resistor layer is arranged on the conducting layer, and the resistance value of the NTC resistor layer is inversely related to the temperature.

2. The tab as claimed in claim 1, wherein the conductive layer has a welding area welded with the current collector, and the NTC resistive layer covers the welding area.

3. The tab as claimed in claim 1, wherein the NTC resistive layer is disposed to surround the conductive layer.

4. The tab as claimed in claim 1, wherein the NTC resistive layer is prepared based on a mixed oxide of cobalt oxide and manganese oxide.

5. The tab as claimed in any one of claims 1 to 4, wherein the NTC resistive layer has a thickness of 250 nm to 600 nm.

6. The tab as claimed in any one of claims 1 to 4, wherein the conductive layer is a tab metal strip, and the conductive layer has a thickness of 0.05 mm to 1 mm and a width of 3 mm to 50 mm.

7. The tab as claimed in any one of claims 1 to 4, further comprising a tab glue, wherein the tab glue is sleeved on the conductive layer;

the thickness of the tab glue is 0.05-0.5 mm, and the width of the tab glue is 5-60 mm.

8. A battery cell comprising a current collector and the tab of claims 1 to 7, wherein the tab is welded to the current collector.

9. The battery cell of claim 8, wherein the non-welded regions on the conductive layers of the tabs are provided with an NTC resistive layer.

10. A cold-joint identification method for identifying the battery cell of claim 8, the method comprising:

detecting the internal resistance value of the battery cell under the condition that the battery cell is in a preset temperature environment;

under the condition that the internal resistance value is within a preset resistance value range, determining that welding of a lug of the battery cell and a current collector of the battery cell fails to fuse the lug and the current collector together;

wherein the temperature range corresponding to the preset temperature environment is-40 ℃ to-20 ℃.

Technical Field

The application belongs to the technical field of batteries, and particularly relates to a tab, a battery cell and a rosin joint identification method.

Background

At present, a welding mode is generally adopted in the process of connecting a tab and a current collector. For example, in the process of connecting the tab and the current collector by using ultrasonic welding, the tab and the current collector are subjected to surface hot melting by using a friction welding principle so as to achieve molecular diffusion melting. Wherein, if utmost point ear and the mass flow body of the welding in-process are not fused completely, can influence the electron transfer of the mass flow body and lead to outside electric quantity loss, serious still can lead to the unable charge-discharge of battery electric core. Therefore, in order to prevent the battery cell from failing to be welded from flowing into the next process, the welding effect of the tab and the current collector needs to be detected. However, in the welding process, the tab and the current collector are already combined together, so that it is difficult to accurately detect the welding effect of the tab and the current collector by using a common detection means, that is, the welding effect of the tab and the current collector has a problem of great detection difficulty.

Therefore, in the related art, the problem of high detection difficulty exists in the welding effect of the tab and the current collector.

Disclosure of Invention

The application aims to provide a tab, a battery cell and a rosin joint identification method, and the problem that the detection difficulty is high in the welding effect of the tab and a current collector in the related technology can be solved.

In order to solve the technical problem, the present application is implemented as follows:

in a first aspect, an embodiment of the present application provides a tab, including: the temperature-sensitive resistor comprises a conducting layer and a Negative Temperature Coefficient (NTC) resistor layer, wherein the NTC resistor layer is arranged on the conducting layer, and the resistance value of the NTC resistor layer is inversely related to the temperature.

Optionally, the conductive layer has a welding area welded with the current collector, and the NTC resistive layer covers the welding area.

Optionally, the NTC resistive layer is disposed to surround the conductive layer.

Optionally, the NTC resistive layer is prepared based on a cobalt oxide and manganese oxide mixed oxide.

Optionally, the NTC resistive layer has a thickness of 250 nm to 600 nm.

Optionally, the conductive layer is a tab metal strip, the thickness of the conductive layer is 0.05 mm to 1 mm, and the width of the conductive layer is 3 mm to 50 mm.

Optionally, the conductive layer further comprises a tab glue, and the tab glue is sleeved on the conductive layer;

the thickness of the tab glue is 0.05-0.5 mm, and the width of the tab glue is 5-60 mm.

In a second aspect, an embodiment of the present application provides a battery cell, including a current collector and the tab according to the first aspect, and the tab is welded to the current collector.

Optionally, a non-welding region on the conductive layer of the tab is provided with an NTC resistive layer.

In a third aspect, an embodiment of the present application provides a cold joint identification method, which is used for identifying a battery electric core as in the second aspect, and the method includes:

detecting the internal resistance value of the battery cell under the condition that the battery cell is in a preset temperature environment;

under the condition that the internal resistance value is within a preset resistance value range, determining that welding of a lug of the battery cell and a current collector of the battery cell fails to fuse the lug and the current collector together;

wherein the temperature range corresponding to the preset temperature environment is-40 ℃ to-20 ℃.

In the embodiment of the application, the NTC resistive layer is arranged on the conductive layer, and then, in a low-temperature environment, whether the NTC resistive layer is damaged by a welding head formed by welding a tab and a current collector or not is judged by detecting the internal resistance value of the battery cell and according to the change condition of the internal resistance value of the battery cell or the resistance value interval where the internal resistance value of the battery cell is located; if the NTC resistance layer is not damaged, namely the NTC resistance layer also has the characteristic of resistance value increase along with temperature reduction, determining that the conducting layer and the current collector are not fused together; if the NTC resistance layer is damaged, namely the NTC resistance layer loses the characteristic of resistance value increase along with temperature reduction, determining that the conducting layer and the current collector are fused together; therefore, the detection of the welding effect of the lug of the battery cell and the current collector is realized, and the detection difficulty of the welding effect of the lug of the battery cell and the current collector is reduced.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is one of schematic structural diagrams of a tab provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

FIG. 3 is one of the cross-sectional views A-A of FIG. 2;

FIG. 4 is a second cross-sectional view taken along A-A of FIG. 2;

fig. 5 is a schematic view of a detection scenario of an internal resistance value of a battery electric core according to an embodiment of the present application;

fig. 6 is a second schematic structural diagram of a tab provided in the embodiment of the present application;

FIG. 7 is a cross-sectional view taken along line B-B of FIG. 6;

fig. 8 is a third schematic structural diagram of a tab provided in an embodiment of the present application;

FIG. 9 is a cross-sectional view taken along line C-C of FIG. 8;

fig. 10 is a fourth schematic structural view of a tab provided in an embodiment of the present application;

FIG. 11 is a cross-sectional view taken along line D-D of FIG. 10;

fig. 12 is a fifth schematic structural view of a tab provided in the embodiment of the present application;

FIG. 13 is a cross-sectional view taken along line E-E of FIG. 12;

FIG. 14 is a flow chart of a cold joint identification method provided by an embodiment of the present application;

fig. 15 is a structural diagram of a cold joint recognition apparatus according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

As shown in fig. 1, the present embodiment provides a tab, where the tab 10 includes: a conductive layer 11 and an NTC (Negative Temperature Coefficient) resistive layer 12, the NTC resistive layer 12 being disposed on the conductive layer 11, and a resistance value of the NTC resistive layer 12 being inversely related to Temperature.

In the NTC resistive layer 12, the resistance value increases rapidly with a decrease in temperature without damaging the structure.

In the present embodiment, the NTC resistive layer 12 is provided on the conductive layer 11, so that whether the tab 10 and the current collector of the battery cell are fused together is detected based on a relationship between the resistance value of the NTC resistive layer 12 and the temperature.

The tab 10 further includes a tab glue 13, and the tab glue 13 is sleeved on the conductive layer 11.

In one embodiment, the thickness of the tab glue 13 is 0.05 mm to 0.5 mm, and the width of the tab glue 13 is 5 mm to 60 mm.

As shown in fig. 2, during the welding of the tab 10 and the current collector 20, the tab 10 may be welded to the empty foil area 21 of the current collector 20 by ultrasonic welding; and during the welding process, the NTC resistive layer 12 of the tab 10 may be damaged by the friction welding so that the conductive layer 11 of the tab 10 is fused with the current collector 20.

As shown in fig. 3, in the case where the conductive layer 11 is fused with the current collector 20, the structure of the NTC resistance layer 12 may be damaged by the welding head 30 formed by welding the tab 10 and the current collector 20, so that the NTC resistance layer 12 loses the characteristics having a negative temperature dependency, that is, the NTC resistance layer 12 no longer has the characteristics of increasing resistance value with decreasing temperature.

As shown in fig. 4, in a case where the conductive layer 11 and the current collector 20 are not fused together, that is, the structure of the NTC resistive layer 12 is not damaged by the welding head 30 formed by welding the tab 10 and the current collector 20, so that the NTC resistive layer 12 also maintains the characteristic of negative temperature dependence, that is, the NTC resistive layer 12 also has the characteristic of increasing resistance value with decreasing temperature.

Therefore, the NTC resistance layer 12 is arranged on the conductive layer 11, and then, in a low-temperature environment, by detecting the internal resistance value of the battery cell, whether the NTC resistance layer is damaged by the welding head 30 formed by welding the tab 10 and the current collector 20 can be determined according to the change condition of the internal resistance value of the battery cell or the resistance value interval where the internal resistance value of the battery cell is located; if the NTC resistive layer is not damaged, i.e., the NTC resistive layer 12 also has a characteristic of increasing resistance value with decreasing temperature, it is determined that the conductive layer 11 and the current collector 20 are not fused together; if the NTC resistive layer is damaged, that is, the NTC resistive layer 12 loses its characteristic of increasing resistance value with decreasing temperature, it is determined that the conductive layer 11 is fused with the current collector 20; therefore, the detection of the welding effect of the tab 10 and the current collector 20 of the battery cell is realized, and the detection difficulty of the welding effect of the tab 10 and the current collector 20 of the battery cell is reduced.

As shown in fig. 5, the battery cells 100 may be placed in the low-temperature box 200, and the internal resistance values of the battery cells 100 placed in the low-temperature box 200 may be detected by a multimeter; two contacts of the multimeter can be distributed and electrically connected with the positive tab 110 and the negative tab 120 of the battery electric core 100, so as to detect the internal resistance value of the battery electric core 100.

If the detected internal resistance value of the battery cell is within the preset resistance value range, that is, the NTC resistance layer 12 further has the characteristic that the resistance value is increased along with the temperature reduction, that is, the conductive layer 11 and the current collector 20 are not fused together, it is determined that the tab 10 and the current collector 20 have a cold joint condition in the welding process, the battery cell with the cold joint is not prevented from flowing into the next process, and the battery cell with the cold joint can be picked out, so that the yield of the battery manufactured based on the battery cell is improved.

The tab 10 includes a positive tab and a negative tab, and the conductive layer 11 of the positive tab may be an aluminum layer, i.e., a conductive layer made of metallic aluminum; the conductive layer 11 of the negative electrode tab may be a nickel layer, i.e., a conductive layer made of metallic nickel.

In one embodiment, the conductive layer 11 may be a tab metal strip, and the thickness of the conductive layer 11 is 0.05 mm to 1 mm, and the width of the conductive layer is 3 mm to 50 mm.

Wherein the NTC resistive layer 12 may be disposed on the conductive layer 11 by means of coating or chemical vapor deposition.

In one embodiment, the NTC resistive layer 12 may be prepared based on a mixed oxide of cobalt oxide and manganese oxide.

In another embodiment, the NTC resistive layer 12 has a thickness of 250 nm to 600 nm, and a material constant B of 5000-.

In addition, after the NTC resistance layer 12 is disposed on the conductive layer 11, the tab 10 may be further chromized, and a finished tab may be obtained through processes such as tab glue 13 packaging.

As shown in fig. 6 and 7, the NTC resistive layer 12 may be disposed at one end of the conductive layer 11 welded to the current collector 20, that is, the NTC resistive layer 12 may be disposed on both sides of the conductive layer 11, so that both sides of the conductive layer 11 can be welded to the current collector 20, thereby improving welding efficiency. In addition, by providing the NTC resistance layer 12 only at one end of the conductive layer 11 for welding, the material used for the NTC resistance layer 12 can be reduced, and the manufacturing cost of the tab can be reduced. Wherein, the coating length of the NTC resistive layer 12 is less than or equal to 35 mm.

As shown in fig. 8 and 9, the NTC resistive layer 12 may be disposed to wrap the conductive layer 11, so that both ends of the conductive layer 11 can be welded to the current collector 20, thereby improving the welding efficiency between the tab 10 and the current collector 20.

As shown in fig. 10 and 11, the NTC resistive layer 12 may be provided only on the end surface of the conductive layer 11 welded to the current collector 20; compared with the tab shown in fig. 6 and 7, the material consumption of the NTC resistive layer 12 can be further reduced, and the manufacturing cost of the tab can be reduced. Wherein, the coating length of the NTC resistive layer 12 is less than or equal to 35 mm.

As shown in fig. 12 and 13, the NTC resistive layer 12 may be provided only on the end surface of the conductive layer 11 welded to the current collector 20; compared with the tab shown in fig. 8 and 9, the material consumption of the NTC resistive layer 12 can be reduced, and the manufacturing cost of the tab can be reduced.

As shown in fig. 2 to 5, an embodiment of the present application further provides a battery cell, which includes a current collector 20 and the tab 10 in the above embodiment, and the tab 10 is welded to the current collector 20.

In the embodiment, the NTC resistance layer 12 is arranged on the conductive layer 11, and then, in a low-temperature environment, the internal resistance value of the battery core of the battery roll core battery is detected, and whether the NTC resistance layer is damaged by the welding head 30 formed by welding the tab 10 and the current collector 20 can be judged according to the change condition of the internal resistance value of the battery core of the battery roll core battery or the resistance value interval where the internal resistance value of the battery core of the battery roll core battery is located; if the NTC resistive layer is not damaged, i.e., the NTC resistive layer 12 also has a characteristic of increasing resistance value with decreasing temperature, it is determined that the conductive layer 11 and the current collector 20 are not fused together; if the NTC resistive layer is damaged, that is, the NTC resistive layer 12 loses its characteristic of increasing resistance value with decreasing temperature, it is determined that the conductive layer 11 is fused with the current collector 20; therefore, the detection of the welding effect of the lug 10 and the current collector 20 of the battery roll core battery cell is realized, and the detection difficulty of the welding effect of the lug 10 and the current collector 20 of the battery roll core battery cell is reduced.

The temperature range of the low-temperature environment can be-40 ℃ to-20 ℃, namely, the battery core of the battery roll core battery can be placed in the low-temperature environment with the temperature of-40 ℃ to-20 ℃ to detect the internal resistance value of the battery roll core battery core.

In one embodiment, under a normal temperature environment, the contact resistance between the tab 10 and the current collector 20 is about 0.07m Ω; however, in a low-temperature environment, for example, in a low-temperature environment with a temperature of-40 ℃ to-20 ℃, due to the presence of the NTC resistance layer 12, the internal resistance of the core of the battery core-wound battery can be rapidly increased by 3-8m Ω along with the decrease of the temperature, that is, in the low-temperature environment, by detecting the internal resistance of the core of the battery core-wound battery, whether the NTC resistance layer 12 is damaged by the welding head 30 formed by welding the tab 10 and the current collector 20 can be determined, so that the detection of the welding effect of the tab 10 and the current collector 20 of the core of the battery core-wound battery is realized, and the detection difficulty of the welding effect of the tab 10 and the current collector 20 of the core.

As shown in fig. 6 to 13, the non-welding area on the conductive layer 11 of the tab 10 is provided with the NTC resistive layer 12, that is, the area of the NTC resistive layer 12 on the conductive layer 11 of the tab 10 is larger than the area of the welding area of the conductive layer 11, so as to ensure that the welding area of the conductive layer 11 is within the coverage of the NTC resistive layer 12 on the conductive layer 11, thereby improving the detection accuracy; and the problem of inaccurate detection result caused by process error can be avoided.

The embodiment of the application also provides a battery, which comprises the battery cell in the embodiment.

It should be noted that the implementation manner of the battery cell embodiment is also applicable to the battery embodiment, and can achieve the same technical effect, and details are not described herein again.

As shown in fig. 14, an embodiment of the present application further provides a cold joint identification method, where the method is used to identify a battery cell in the foregoing embodiment, and includes:

step 1401, detecting an internal resistance value of the battery electric core under the condition that the battery electric core is in a preset temperature environment.

In this step, the internal resistance value of the battery electric core can be detected by a universal meter.

Step 1402, under the condition that the internal resistance value is within the preset resistance value range, it is determined that welding of the tab of the battery electric core and the current collector of the battery electric core fails to fuse the tab and the current collector together.

Wherein the temperature range corresponding to the preset temperature environment is-40 ℃ to-20 ℃.

In this way, the battery cell is placed in a preset temperature environment, the internal resistance value of the battery cell is detected, and then the conductive layer and the current collector are determined not to be fused together under the condition that the change condition of the internal resistance value of the battery cell meets a preset condition or a preset resistance value interval in which the internal resistance value of the battery cell is located, namely the condition of the cold joint existing in the welding between the lug of the battery cell and the current collector; therefore, the detection of the welding effect of the lug of the battery cell and the current collector is realized, and the detection difficulty of the welding effect of the lug of the battery cell and the current collector is reduced.

In addition, if the detected resistance value does not meet the preset condition or the internal resistance value is not in the preset resistance value interval, it is determined that the conductive layer and the current collector are fused together, that is, the condition of insufficient soldering between the tab of the battery cell and the current collector does not exist.

As shown in fig. 15, an embodiment of the present application further provides a cold joint identification apparatus, where the cold joint identification apparatus 1500 includes:

the detection module 1501 is configured to detect an internal resistance value of the battery cell under a preset temperature environment;

a determining module 1502, configured to determine that welding of a tab of the battery cell and a current collector of the battery cell fails to fuse the tab and the current collector together, when the internal resistance value is within a preset resistance value interval;

wherein the temperature range corresponding to the preset temperature environment is-40 ℃ to-20 ℃.

The rosin joint identification apparatus provided in the embodiment of the present application can implement each process implemented by the method embodiment of fig. 14, and is not described here again to avoid repetition.

In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.