Method and device for measuring contact resistance of pole piece

Abstract

The method and the device for measuring the contact resistance of the pole pieces are provided, the pole pieces comprise a positive pole piece and a negative pole piece, in the thickness direction of the pole pieces, the positive pole piece comprises a positive active material, a positive current collector and a positive active material which are arranged in sequence, and the negative pole piece comprises a negative active material which is arranged in sequence. The method comprises the following steps: acquiring the total resistance between the positive pole piece and the negative pole piece; obtaining internal resistance; obtaining the contact resistance of the pole piece according to the total resistance and the internal resistance; and adjusting the temperature and humidity of the space where the positive pole piece and the negative pole piece are located, so as to obtain the pole piece contact resistance of the pole pieces at different temperatures and humidity.

Description

Technical Field

[0001] This application relates to the field of electrode contact resistance measurement technology, and particularly to a method and apparatus for measuring electrode contact resistance. Background Technology

[0002] An internal short circuit in a lithium-ion battery refers to an abnormal, undesigned direct electrical connection between the positive and negative electrodes inside the battery. Once an internal short circuit occurs, a huge local current is generated at the short circuit point, causing a rapid accumulation of Joule heat and a rapid increase in local temperature. The high temperature will trigger a series of chain exothermic reactions inside the battery, such as separator shrinkage, melting, and even rupture; thermal decomposition of the positive and negative electrode active materials; and oxidative decomposition of the electrolyte. These reactions further release a large amount of heat, which may eventually lead to thermal runaway, causing serious consequences such as smoke, fire, or even explosion.

[0003] Depending on the location of the short circuit and the materials involved, internal short circuits in lithium-ion batteries can generally be classified into four main types: 1) short circuit between the positive electrode current collector (aluminum foil) and the negative electrode current collector (copper foil); 2) direct contact short circuit between the positive electrode active material and the negative electrode active material; 3) short circuit between the negative electrode active material and the positive electrode current collector (aluminum foil); and 4) short circuit between the positive electrode active material and the negative electrode current collector (copper foil). Due to differences in the electrochemical properties, interfacial reactions, and thermal stability of the materials involved, these four types of short circuits exhibit significant differences in short-circuit resistance, heat generation rate, and subsequent reactions, ultimately potentially leading to completely different thermal runaway evolution paths and severity.

[0004] In studies of internal short circuit and thermal runaway mechanisms, the contact resistance between electrodes or between electrodes and current collectors is a crucial parameter. It directly affects the magnitude of the initial short circuit current, the heat generation power, and the heat accumulation process, and is one of the key factors determining whether an internal short circuit will evolve into thermal runaway. However, existing studies on internal short circuit and thermal runaway mechanisms lack accurate and reliable input data on contact resistance. Currently, the industry lacks a reliable method to accurately quantify electrode contact resistance under actual operating conditions. Existing resistance measurement techniques, such as single-probe, two-probe, four-probe, or multi-probe methods, have significant limitations when applied to such interface contact resistance measurements. These methods often struggle to completely eliminate interference from additional resistances such as wire resistance and probe contact resistance, leading to large measurement errors. More importantly, under actual operating or abuse conditions, the contact state between electrodes is significantly affected by multiple factors, including pressure, temperature, and even ambient humidity. For example, the expansion and contraction of the cell during cycling changes the interfacial pressure, and temperature changes affect the conductivity and contact tightness of the materials.

[0005] In view of this, there is an urgent need to provide a method and apparatus for measuring electrode contact resistance, so as to accurately measure the contact resistance without introducing additional resistance, and to obtain the change of contact resistance with temperature and humidity. Summary of the Invention

[0006] This application is made in view of the aforementioned state of the prior art. This application provides a method and apparatus for measuring the contact resistance of an electrode.

[0007] A method for measuring the contact resistance of an electrode is provided, wherein the electrode includes a positive electrode and a negative electrode, wherein, in the thickness direction of the electrode, the positive electrode includes a positive active material, a positive current collector, and a positive active material arranged sequentially, and the negative electrode includes a negative active material, a negative current collector, and a negative active material arranged sequentially. The method includes: obtaining the total resistance between the positive electrode and the negative electrode; obtaining the internal resistance; wherein the total resistance includes the positive current-collecting resistance of the positive current collector and the negative current-collecting resistance of the negative current collector, and further includes the positive active resistance of the positive active material, the negative active resistance of the negative active material, the positive contact resistance between the positive current collector and the positive active material, the negative contact resistance between the negative current collector and the negative active material, and the first contact resistance between the positive active material and the negative active material; the internal resistance includes the sum of the positive active resistance and the positive contact resistance, the sum of the negative active resistance and the negative contact resistance, the positive current-collecting resistance, and the negative current-collecting resistance; or the total resistance further includes the positive active resistance of the positive active material, the positive contact resistance between the positive current collector and the positive active material, and the resistance between the negative current collector and the positive active material. The second contact resistance between materials; the internal resistance includes the sum of the positive electrode active resistance and the positive electrode contact resistance, the positive electrode current collector resistance, and the negative electrode current collector resistance; or the total resistance also includes the negative electrode active resistance of the negative electrode active material, the negative electrode contact resistance between the negative electrode current collector and the negative electrode active material, and the third contact resistance between the positive electrode current collector and the negative electrode active material; the internal resistance includes the sum of the negative electrode active resistance and the negative electrode contact resistance, the positive electrode current collector resistance, and the negative electrode current collector resistance; or the total resistance also includes the fourth contact resistance between the positive electrode current collector and the negative electrode current collector; the internal resistance includes the positive electrode current collector resistance and the negative electrode current collector resistance; the electrode contact resistance is obtained based on the total resistance and the internal resistance; and the temperature and humidity of the space where the positive electrode and the negative electrode are located are adjusted to obtain the electrode contact resistance of the electrode under different temperatures and humidity conditions.

[0008] Optionally, obtaining the total resistance between the positive electrode and the negative electrode includes: pre-processing the positive electrode and the negative electrode to obtain a positive-processed electrode and a negative-processed electrode; stacking the positive-processed electrode, the central insulating sheet, and the negative-processed electrode sequentially together along the thickness direction of the electrode, wherein the central insulating sheet has a through hole; and measuring the resistance between the positive-processed electrode and the negative-processed electrode to obtain the total resistance.

[0009] Optionally, the pretreatment of the positive electrode and the negative electrode includes: peeling off the positive active material from the edge region of the positive electrode to expose the positive current collector for connection to one end of the resistance measuring device; and peeling off the negative active material from the edge region of the negative electrode to expose the negative current collector for connection to the other end of the resistance measuring device.

[0010] Optionally, the pretreatment of the positive electrode and the negative electrode further includes: stripping the positive active material from the middle region of the positive electrode to expose at least a portion of the positive current collector in the middle region of the positive electrode, and / or stripping the negative active material from the middle region of the negative electrode to expose at least a portion of the negative current collector in the middle region of the negative electrode.

[0011] Optionally, after the positive electrode, the central insulating sheet, and the negative electrode are stacked together in sequence, the exposed positive current collector in the middle region of the positive electrode is positioned opposite to the through hole, and / or the exposed negative current collector in the middle region of the negative electrode is positioned opposite to the through hole.

[0012] Optionally, measuring the resistance between the positive electrode and the negative electrode to obtain the total resistance includes: pressing the positive electrode, the central insulating sheet, and the negative electrode together along the thickness direction of the electrode, such that the positive electrode and the negative electrode are in contact through the through hole.

[0013] Optionally, obtaining the sum of the positive active resistance and the positive contact resistance of the internal resistance includes: stacking two identical positive electrode sheets together along the thickness direction of the electrode sheets in such a way that the central insulating sheet is sandwiched between them; pressing them along the thickness direction of the electrode sheets so that the positive active materials of the two positive electrode sheets are in contact with each other through the through hole; measuring the resistance between the positive current collectors of the two positive electrode sheets to obtain a first resistance; and obtaining the sum of the positive active resistance and the positive contact resistance based on the first resistance and the positive current collector resistance.

[0014] Optionally, obtaining the sum of the negative electrode active resistance and the negative electrode contact resistance of the internal resistance includes: stacking two identical negative electrode sheets together along the thickness direction of the electrode sheets in such a way that the central insulating sheet is sandwiched between them; pressing them along the thickness direction of the electrode sheets so that the negative electrode active materials of the two negative electrode sheets are in contact with each other through the through hole; measuring the resistance between the negative electrode current collectors of the two negative electrode sheets to obtain a second resistance; and obtaining the sum of the negative electrode active resistance and the negative electrode contact resistance based on the second resistance and the negative electrode current collector resistance.

[0015] Embodiments of this application also provide an apparatus for measuring electrode contact resistance, the apparatus including a housing, a measuring cavity formed within the housing, and a method for measuring electrode contact resistance according to this application performed within the measuring cavity.

[0016] Optionally, a base is provided inside the measuring cavity for placing the positive electrode and / or the negative electrode; a pressure block is provided above the base, and the pressure block can move along the thickness direction of the electrode to compress the positive electrode and / or the negative electrode.

[0017] Optionally, the device further includes a resistance measuring device for measuring the resistance of the component under test within the measuring cavity.

[0018] Optionally, the device further includes: a temperature regulating device for adjusting the temperature of the measuring cavity; a temperature measuring device for measuring the temperature of the measuring cavity; a humidity regulating device for adjusting the humidity of the measuring cavity; and a humidity measuring device for measuring the humidity of the measuring cavity.

[0019] Using the method and apparatus for measuring electrode contact resistance provided above, the solution of this application obtains the total resistance between the positive electrode and the negative electrode; based on the total resistance and the internal resistance, it obtains the electrode contact resistance; and by adjusting the temperature and humidity of the space where the positive and negative electrodes are located, it obtains the electrode contact resistance under different temperatures and humidity conditions. Thus, the variation of contact resistance with temperature and humidity can be obtained. Attached Figure Description

[0020] Figure 1A An exemplary block diagram of a method for measuring electrode contact resistance according to one embodiment of this application is shown.

[0021] Figure 1B An exemplary block diagram is shown illustrating an embodiment of the present application for obtaining the total resistance between the positive and negative electrodes.

[0022] Figure 2AAn exemplary structural diagram of a positive electrode sheet according to one embodiment of this application is shown.

[0023] Figure 2B An exemplary structural diagram of a negative electrode sheet according to one embodiment of this application is shown.

[0024] Figure 3 An exemplary structural diagram of a total resistance measurement method for measuring electrode contact resistance according to a first embodiment of this application is shown.

[0025] Figure 4 An exemplary structural diagram of the total resistance for measuring the contact resistance of the electrode according to a second embodiment of this application is shown.

[0026] Figure 5 An exemplary structural diagram of measuring the total resistance of the electrode contact resistance according to a third embodiment of this application is shown.

[0027] Figure 6 An exemplary structural diagram of measuring the total resistance of the electrode contact resistance according to the fourth embodiment of this application is shown.

[0028] Figure 7 An exemplary structural diagram of a device for measuring the internal resistance of an electrode contact according to some embodiments of this application is shown.

[0029] Figure 8 An exemplary structural diagram of a measuring electrode contact resistance measuring internal resistance according to other embodiments of this application is shown.

[0030] Figure 9A An exemplary structural diagram of a measuring electrode contact resistance measuring internal resistance according to other embodiments of this application is shown.

[0031] Figure 9B An exemplary structural diagram of a measuring electrode contact resistance measuring internal resistance according to other embodiments of this application is shown.

[0032] Figure 10A An exemplary structural diagram of a measuring electrode contact resistance measuring internal resistance according to other embodiments of this application is shown.

[0033] Figure 10B An exemplary structural diagram of a measuring electrode contact resistance measuring internal resistance according to other embodiments of this application is shown.

[0034] Figure 11 An exemplary structural diagram of an apparatus for measuring electrode contact resistance according to one embodiment of this application is shown.

[0035] Figure 12An exemplary coordinate graph showing the relationship between electrode contact resistance and temperature, humidity, and pressure according to one embodiment of this application is shown. Detailed Implementation

[0036] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0037] This application provides a method 100 for measuring the contact resistance of an electrode, wherein the electrode includes a positive electrode 10 and a negative electrode 20. Along the thickness direction H of the electrode, the positive electrode 10 includes a positive active material 11, a positive current collector 12, and a positive active material 11 (e.g., ...) sequentially arranged. Figure 2A As shown), the negative electrode plate 20 includes a negative electrode active material 21, a negative electrode current collector 22, and a negative electrode active material 21 (as shown) arranged sequentially. Figure 2B (As shown). That is, in the thickness direction H of the electrode sheet, positive electrode active material 11 can be respectively disposed on both sides of the positive electrode current collector 12, and negative electrode active material 21 can be respectively disposed on both sides of the negative electrode current collector 22.

[0038] Furthermore, such as Figure 1A As shown, the method 100 for measuring electrode contact resistance may specifically include:

[0039] Step S110: Obtain the total resistance R between the positive electrode 10 and the negative electrode 20. It should be understood that the required total resistance R differs under different short-circuit conditions. The following will provide a detailed explanation of the total resistance using different embodiments.

[0040] Step S120: Obtain the internal resistance. It should be understood that the internal resistance differs under different short-circuit conditions. The following will provide a detailed explanation of the internal resistance using different embodiments.

[0041] Step S130: Obtain the electrode contact resistance based on the total resistance R and the internal resistance. It should be understood that the contact resistance may include a first contact resistance, a second contact resistance, a third contact resistance, and a fourth contact resistance. The aforementioned different electrode contact resistances can correspond to different short-circuit conditions. The following will describe in detail the aforementioned different electrode contact resistances in conjunction with the first, second, third, and fourth embodiments.

[0042] Step S140: Adjust the temperature and humidity of the space where the positive and negative electrodes are located to obtain the electrode contact resistance under different temperatures and humidity conditions.

[0043] It is important to understand that the first contact resistance R (described later) varies with different temperatures. 11_21 Second contact resistance R 22_11 Third contact resistance R 12_21 and the fourth contact resistance R 12_22 It may change. Therefore, the change in contact resistance with temperature and humidity can be obtained by adjusting the temperature and humidity of the environment where the positive electrode 10 and the negative electrode 20 are located.

[0044] Furthermore, such as Figure 1B As shown, in step S110, the total resistance R between the positive electrode 10 and the negative electrode 20 can be obtained by the following method:

[0045] Step S111: Pre-process the positive electrode 10 and / or the negative electrode 20 to obtain the positive electrode processed electrode 101 and the negative electrode processed electrode 201.

[0046] Step S112 can be seen at the same time. Figure 3 Along the thickness direction H of the electrode sheet, the positive electrode treatment electrode 101, the central insulating sheet 32 ​​and the negative electrode treatment electrode 201 are stacked together in sequence, wherein the central insulating sheet 32 ​​has a through hole 321.

[0047] It should be understood that the aforementioned positive electrode 101 can be disposed on the lower side, the negative electrode 201 can be disposed on the upper side, and the central insulating sheet 32 ​​can be disposed between the positive electrode 101 and the negative electrode 201. Similarly, the aforementioned positive electrode 101 can also be disposed on the upper side, and the negative electrode 201 can be disposed on the lower side; this application does not impose any restrictions on this.

[0048] Furthermore, a bottom insulating sheet 31 can be provided at the bottom of the aforementioned positive electrode treatment electrode 101, the central insulating sheet 32, and the negative electrode treatment electrode 201, and a top insulating sheet 33 can be provided at the top.

[0049] Step S113: Measure the resistance between the positive electrode 101 and the negative electrode 201 to obtain the total resistance R.

[0050] Specifically, the clamps of the resistance measuring device can be clamped onto the positive electrode 101 and the negative electrode 201.

[0051] After setting up the resistance measuring device, the positive electrode 101, the central insulating sheet 32, and the negative electrode 201 stacked together can be pressed along the thickness direction H of the electrode, so that the positive electrode 101 and the negative electrode 201 make contact through the through hole 321.

[0052] It's important to understand that by adjusting the squeezing pressure, the change in contact resistance with pressure can be observed. Specifically, for example... Figure 11 As shown, the pressure of extrusion can be adjusted by adjusting the output pressure of the pressure block 41.

[0053] It should be understood that making the positive electrode 101 and the negative electrode 201 contact through the through hole 321 can include: the positive electrode 101 passing through the through hole 321 to contact the negative electrode 201, or the negative electrode 201 passing through the through hole 321 to contact the positive electrode 101.

[0054] It is understandable that the electrode contact resistance can vary under different short-circuit conditions. Specifically, the electrode contact resistance may include: the first contact resistance R. 11_21 Second contact resistance R 22_11 Third contact resistance R 12_21 and the fourth contact resistance R 12_22 .

[0055] It is important to understand that the first contact resistance R 11_21 The resistance formed by the contact between the positive electrode active material 11 and the negative electrode active material 21; the second contact resistance R 22_11 The resistance formed by the contact between the negative electrode current collector 22 and the positive electrode active material 11; the third contact resistance R 12_21 The resistance formed by the contact between the positive electrode current collector 12 and the negative electrode active material 21; the fourth contact resistance R 12_22 It can be the resistance formed by the contact between the positive current collector 12 and the negative current collector 22.

[0056] Furthermore, the total resistance R and the internal resistance are different under different short-circuit conditions. The electrode contact resistance of the electrode will be obtained according to different short-circuit conditions below.

[0057] First Embodiment

[0058] A method for measuring electrode contact resistance may include: Step S110: Obtaining the total resistance R between the positive electrode 10 and the negative electrode 20. In this embodiment, the electrode contact resistance to be measured may be the first contact resistance R formed by the contact between the positive active material 11 and the negative active material 21. 11_21 .

[0059] It is understandable that, in order to obtain the total resistance R, the positive electrode 10 and the negative electrode 20 can be pre-processed to obtain the positive electrode processed electrode 101 and the negative electrode processed electrode 201. The aforementioned positive electrode 10 and negative electrode 20 can be set as circular or rectangular, etc. When they are rectangular, their length can be 80mm and their width can be 50mm.

[0060] It should be understood that the pretreatment of the positive electrode 10 may include: peeling off the positive active material 11 from the edge region of the positive electrode 10 to expose the positive current collector 12, which can be connected to one end of a resistance measuring device. Specifically, the positive active material 11 on the edge region of the positive electrode 10 located in the left-right direction (LR) can be peeled off, thereby peeling off the positive active material 11 on both the upper and lower sides of the positive current collector 12 in this edge region, so that the positive current collector 12 can be exposed.

[0061] For example, such as Figure 3 As shown, the positive active material 11 in the right region of the positive electrode 10 is stripped off, thereby exposing the positive current collector 12 on the right side of the positive electrode 10. Furthermore, the exposed positive current collector 12 can be connected to the clip of a resistance measuring device.

[0062] Similarly, pre-treating the negative electrode 20 may include: peeling off the negative electrode active material 21 from the edge region of the negative electrode 20 to expose the negative electrode current collector 22, which can be connected to the other end of the resistance measuring device. Figure 3 As shown, the negative electrode active material 21 on the left side of the negative electrode 20 can be peeled off. The negative electrode current collector 22 on the left side of the negative electrode 20 can then be exposed. Furthermore, the exposed negative electrode current collector 22 can be used to connect to the clip of a resistance measuring device.

[0063] Furthermore, the size of the aforementioned stripped edge region in the left-right direction (LR) of the electrode can be 10mm to facilitate clamping by the clip. It should be understood that the aforementioned size can be the size in the left-right direction (LR) of the electrode.

[0064] It should be understood that the above-described stripping of the positive active material 11 on the right side of the positive electrode 10 and the stripping of the negative active material 21 on the left side of the negative electrode 20 are merely illustrative examples. Similarly, the positive active material 11 on the left side of the positive electrode 10 and the negative active material 21 on the right side of the negative electrode 20 can also be stripped.

[0065] After peeling off the positive active material 11 from the edge region of the aforementioned positive electrode 10, a positive electrode treated electrode 101 can be obtained. After peeling off the negative active material 21 from the edge region of the aforementioned negative electrode 20, a negative electrode treated electrode 201 can be obtained.

[0066] Further, in step S112, along the thickness direction H of the electrode (e.g.) Figure 3In a top-down direction, the bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201, and the top insulating sheet 33 are stacked together in sequence. It should be understood that the center insulating sheet 32 ​​may be provided with a through hole 321, which can be rectangular or circular, etc. When the through hole 321 is circular, its diameter can be 30mm.

[0067] It should be understood that the aforementioned bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape. For example, the stacked bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape.

[0068] Step S113: Measure the resistance between the positive electrode 101 and the negative electrode 201 to obtain the total resistance R.

[0069] Specifically, the clamps of the resistance measuring device can be clamped onto the exposed positive current collector 12 and negative current collector 22 located at the edge region, respectively. It should be understood that the clamps of the aforementioned resistance measuring device can be clamped onto the positive current collector 12 and negative current collector 22 before the top insulating sheet 33 is pressed.

[0070] After clamping, it can be aligned along the thickness direction H of the electrode (e.g., ...). Figure 3 The bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201, and the top insulating sheet 33 are pressed together in a downward direction, so that the negative electrode active material 21 can pass through the through hole 321 and contact the positive electrode active material 11.

[0071] It is understandable that at this time, one end of the aforementioned resistance measuring device can form a path with the other end of the resistance measuring device through the clamp, the positive current collector 12, the positive active material 11 located on the upper side of the positive current collector 12, the negative active material 21 in contact with the positive active material 11, the negative current collector 22 located above the negative active material 21, and the clamp. At this time, the resistance measured by the resistance measuring device can be the total resistance R.

[0072] It is understandable that the total resistance R at this time is: the positive current collector resistance R of positive current collector 12. 12 The positive electrode contact resistance R between the positive current collector 12 and the positive electrode active material 11 12_11 The positive electrode active resistance R of positive electrode active material 11 11 The first contact resistance R between the positive electrode active material 11 and the negative electrode active material 21 11_21The negative electrode active resistance R of negative electrode active material 21 21 The negative electrode contact resistance R between the negative electrode current collector 22 and the negative electrode active material 21 22_21 and the negative current collector resistor R of negative current collector 22 22 sum.

[0073] Further, in step S120, the internal resistance is obtained.

[0074] Specifically, obtaining the internal resistance can include obtaining the positive current collector resistor R. 12 and negative current collector resistor R 22 .

[0075] like Figure 9A As shown, the positive current collector resistor R is obtained. 12 This may include: stripping all the positive active material 11 from the positive electrode 10 to obtain the positive current collector 12.

[0076] It is important to understand that when measuring the total resistance R, only about half of the resistance of the positive current collector 12 is measured (e.g., Figure 3 As shown, the current from the resistance measuring device can flow from the right-hand clamp into the positive current collector 12, and then from the middle region of the positive current collector 12 into the positive active material 11, and from the middle region of the negative active material 21 into the middle region of the negative current collector 22, and further from the left side of the negative current collector 22 into the left-hand clamp of the resistance measuring device. Therefore, it is only necessary to measure approximately half the resistance of the positive current collector 12.

[0077] Specifically, the two ends of the resistance measuring device can be set in the central region and the edge region of the positive current collector 12, respectively, to measure about half of the resistance of the positive current collector 12.

[0078] Similarly, as Figure 9B As shown, the negative current collector resistor R is obtained. 22 This may include: stripping all the negative electrode active material 21 from the negative electrode sheet 20 to obtain the negative electrode current collector 22. Furthermore, the two ends of a resistance measuring device may be respectively positioned in the central region and the edge region of the negative electrode current collector 22 to measure approximately half the resistance of the negative electrode current collector 22.

[0079] Furthermore, obtaining the internal resistance may also include: obtaining the positive electrode active resistance R. 11 Contact resistance R with the positive electrode 12_11 sum.

[0080] like Figure 10AAs shown, two identical positive electrode plates 10 can be stacked together along the thickness direction H of the electrode plates, with a central insulating sheet 32 ​​sandwiched between them. Furthermore, a bottom insulating sheet 31 can be provided at the bottom of the lower positive electrode plate 10, and a top insulating sheet 33 can be provided at the top of the upper positive electrode plate 10.

[0081] The electrode is pressed along the thickness direction H so that the positive active material 11 of the two positive electrode sheets 10 comes into contact with each other through the through hole 321.

[0082] The resistance between the positive current collectors 12 of the two positive electrode plates 10 is measured to obtain the first resistance. Specifically, the positive active material at the edges of the two positive electrode plates 10 can be stripped off, so that the positive current collectors 12 of both positive electrode plates 10 can be exposed. Furthermore, the two clamps of the resistance measuring device can be clamped onto the two exposed positive current collectors 12 respectively, thereby allowing the first resistance to be measured.

[0083] It is understandable that after the positive active materials 11 of the two positive electrode plates 10 are brought into contact through the through hole 321, the first resistance R measured at this time will be... 111 The positive current collector resistor R, including the positive current collector 12, is... 12 The positive electrode contact resistance R between the positive current collector 12 and the positive electrode active material 11 12_11 The positive electrode active resistance R of positive electrode active material 11 11 The resistance between positive electrode active material 11 and positive electrode active material 11, and the positive electrode active resistance R of positive electrode active material 11. 11 The positive electrode contact resistance R between the positive current collector 12 and the positive electrode active material 11 12_11 And the positive current collector resistor R of the positive current collector 12 12 .

[0084] It is understandable that when two positive electrode active materials 11 come into contact, because they are made of the same material, the resistance at their contact can be close to zero. Therefore, the first resistance R 111 It can be obtained from the following formula:

[0085] R 111 = R 12 + R 12_11 + R 11 + R 11 + R 12_11 + R 12

[0086] The first resistance R that attained enlightenment 111 Then, based on the first resistor R 111 and positive current collector resistor R 12The positive active resistor R is obtained. 11 Contact resistance R with the positive electrode 12_11 sum.

[0087] Specifically, the positive electrode active resistor R 11 Contact resistance R with the positive electrode 12_11 The sum can be obtained by the following formula:

[0088] R 11 + R 12_11 =(R 111 -2 R 12 ) / 2

[0089] Therefore, the positive electrode active resistance R 11 Contact resistance R with the positive electrode 12_11 The sum can be obtained from the measured first resistance R. 111 And the measured positive current collector resistance R 12 get.

[0090] Obtaining internal resistance may also include: obtaining negative electrode active resistance R 21 Contact resistance R with negative electrode 22_21 The sum. Specifically, it can be obtained through the following method:

[0091] They are stacked together along the thickness direction H of the electrode sheets in such a way that two identical negative electrode sheets 20 sandwich a central insulating sheet 32 ​​(e.g. Figure 10B (as shown)

[0092] The electrode is pressed along the thickness direction H so that the negative electrode active material 21 of the two negative electrode plates 20 comes into contact with each other through the through hole 321.

[0093] The resistance between the negative current collectors 22 of the two negative electrode plates 20 is measured to obtain the second resistance;

[0094] Based on the second resistor and the negative current collector resistor R 22 The negative electrode active resistor R is obtained. 21 Contact resistance R with negative electrode 22_21 sum.

[0095] It is important to understand that obtaining the negative electrode active resistance R 21 Contact resistance R with negative electrode 22_21 The sum of these and the aforementioned positive electrode active resistance R 11 Contact resistance R with the positive electrode 12_11 The method of summation is basically the same, only the positive electrode 10 in the above process needs to be replaced with the negative electrode 20, which will not be elaborated here.

[0096] It is understandable that the negative electrode active resistor R 21Contact resistance R with negative electrode 22_21 The sum can be obtained by the following formula:

[0097] R 21 + R 22_21 =(R 112 -2 R 22 ) / 2

[0098] Among them, R 112 R is the second resistor. 22 This is the negative current collector resistor.

[0099] Step S130: Based on the total resistance R and the internal resistance, the electrode contact resistance is obtained.

[0100] It should be understood that, in the first embodiment, the total resistance R and the internal resistance have the following relationship:

[0101] R = R 12 +R 22 + R 11 + R 12_11 + R 21 +R 22_21 +R 11_21

[0102] The total resistance R and the positive current collector resistance R were measured. 12 Negative current collector resistor R 22 Positive active resistor R 11 Contact resistance R with the positive electrode 12_11 The sum of the negative electrode active resistance R 21 Contact resistance R with negative electrode 22_21 After summing, the first contact resistance R 11_21 It can be calculated using the following formula:

[0103] R 11_21 = R- R 12 -R 22 -(R) 11 + R 12_11 )-(R 21 +R 22_21 )

[0104] It is understandable that the solution in this application obtains the first contact resistance R. 11_21 At that time, the first contact resistance R was not directly measured using a resistance measuring device. 11_21 Instead, the first contact resistance R is indirectly obtained by measuring the total resistance R and the internal resistance. 11_21Compared with existing technologies, the solution of this application can avoid the interference of additional resistance (i.e., the internal resistance of the resistance measuring device) and can obtain the first contact resistance more accurately. Similarly, the solution of this application can obtain the second, third, and fourth contact resistances, which will be described later, more accurately.

[0105] Furthermore, after obtaining the first contact resistance R 11_21 Then, by adjusting the temperature and humidity of the space where the positive and negative electrodes are located, the first contact resistance R of the positive and negative electrodes under different temperatures and humidity conditions can be obtained. 11_21 .

[0106] Furthermore, by adjusting the pressure applied to the aforementioned extruded positive electrode 101, central insulating sheet 32, and negative electrode 201, the first contact resistance R can be obtained. 11_21 As the pressure changes.

[0107] Second Embodiment

[0108] As shown in Figure 1, the method for measuring the contact resistance of the electrode plates may include: step S110, obtaining the total resistance R between the positive electrode plate 10 and the negative electrode plate 20.

[0109] Unlike the first embodiment, in the second embodiment, the negative electrode active material in the middle region of the negative electrode sheet needs to be stripped off. This will be explained below with reference to Figure 1 and... Figure 4 Provide a detailed description.

[0110] In the second embodiment, the electrode contact resistance to be measured can be the second contact resistance R formed by the contact between the negative electrode current collector 22 and the positive electrode active material 11. 22_11 .

[0111] It is understandable that, in order to obtain the total resistance R, the positive electrode 10 and the negative electrode 20 can be pre-processed to obtain the positive electrode 101 and the negative electrode 201.

[0112] Specifically, pre-processing the positive electrode 10 and the negative electrode 20 may include: peeling off the positive active material 11 from the edge region of the positive electrode 10 to expose the positive current collector 12, which can be connected to one end of the resistance measuring device. Similarly, peeling off the negative active material 21 from the edge region of the negative electrode 20 to expose the negative current collector 22, which can be connected to the other end of the resistance measuring device.

[0113] like Figure 4As shown, the positive active material 11 on the right side of the positive electrode 10 can be peeled off, thereby exposing the positive current collector 12 on the right side of the positive electrode 10. Furthermore, the negative active material 21 on the left side of the negative electrode 20 can be peeled off, thereby exposing the negative current collector 22 on the left side of the negative electrode 20. Furthermore, both the exposed positive current collector 12 and negative current collector 22 can be used to connect to the clamps of a resistance measuring device.

[0114] Furthermore, the pretreatment of the negative electrode 20 may include: stripping the negative electrode active material 21 from the middle region of the negative electrode 20 so that at least part of the negative electrode current collector 22 is exposed in the middle region of the negative electrode 20.

[0115] It should be understood that the central region of the negative electrode 20 in this application does not refer only to the center of the negative electrode 20. It can be understood that the edge region and the central region of the negative electrode 20 together constitute the negative electrode 20. Similarly, the edge region and the central region of the positive electrode 10 together constitute the positive electrode 10.

[0116] After pre-treating the positive electrode 10 and the negative electrode 20, the positive electrode treated electrode 101 and the negative electrode treated electrode 201 can be obtained.

[0117] Further, in step S112, along the thickness direction H of the electrode (e.g.) Figure 4 (From bottom to top) the bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201 and the top insulating sheet 33 are stacked together in sequence.

[0118] Furthermore, when stacking the central insulating sheet 32 ​​and the negative electrode processing sheet 201, the exposed negative electrode current collector 22 in the middle region of the negative electrode processing sheet 201 is positioned opposite to the through hole 321 of the central insulating sheet 32.

[0119] It is necessary to understand that Figure 4 The negative electrode active material 21 on both the upper and lower sides of the negative electrode current collector 22 shown in the figure has been stripped off.

[0120] In practice, when projecting along the thickness direction H, it is sufficient that the exposed negative electrode current collector 22 at least partially overlaps with the projection of the through hole 321. For example, the central insulating sheet may include an insulating region 322 (such as...). Figure 4 (as shown) and through hole 321. Projected in the thickness direction H, the projection of the negative current collector 22 exposed in the middle region of the negative electrode processing electrode can fall entirely into the projection of the through hole 321, the projection of the negative current collector 22 exposed in the middle region can partially fall into the insulating region 322, and the rest falls into the projection of the through hole 321.

[0121] It should be understood that the aforementioned bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape. For example, the stacked bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape.

[0122] Step S113: Measure the resistance between the positive electrode 101 and the negative electrode 201 to obtain the total resistance R.

[0123] Specifically, the clamps of the resistance measuring device can be clamped onto the exposed positive current collector 12 and negative current collector 22 located at the edge region, respectively. It should be understood that the clamps of the aforementioned resistance measuring device can be clamped onto the positive current collector 12 and negative current collector 22 before the top insulating sheet 33 is pressed.

[0124] After clamping, it can be aligned along the thickness direction H of the electrode (e.g., ...). Figure 4 The bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201, and the top insulating sheet 33 are pressed together in a downward direction, so that the negative current collector 22 of the negative electrode treatment sheet 201 can pass through the through hole 321 and contact the positive electrode active material 11.

[0125] It is understandable that at this time, one end of the aforementioned resistance measuring device can form a path with the other end of the resistance measuring device through the clamp, the positive current collector 12, the positive active material 11 located on the upper side of the positive current collector 12, the negative current collector 22 in contact with the positive active material 11, and the clamp. At this time, the resistance measured by the resistance measuring device can be the total resistance R.

[0126] It is understood that in this embodiment, the total resistance R may include: the positive current collector resistance R of the positive current collector 12. 12 The negative current collector resistor R of negative current collector 22 22 The positive electrode active resistance R of positive electrode active material 11 11 The positive electrode contact resistance R between the positive current collector 12 and the positive electrode active material 11 12_11 and the second contact resistance R between the negative electrode current collector 22 and the positive electrode active material 11 22_11 .

[0127] Furthermore, the second contact resistance R can be obtained by acquiring the internal resistance. 22_11 .

[0128] Specifically, in this embodiment, obtaining the internal resistance may include obtaining the positive active resistance R. 11 Contact resistance R with the positive electrode 12_11 The sum of these values ​​yields the positive current collector resistor R. 12 Obtain the negative current collector resistor R 22 The methods for obtaining internal resistance described above have all been presented in the first embodiment and will not be repeated here.

[0129] It should be understood that, in the second embodiment, the total resistance R and the internal resistance have the following relationship:

[0130] R = R 12 +R 22 + R 11 + R 12_11 + R 22_11

[0131] The total resistance R and the positive current collector resistance R were measured. 12 Negative current collector resistor R 22 Positive active resistor R 11 Contact resistance R with the positive electrode 12_11 After summing, the second contact resistance R 22_11 It can be calculated using the following formula:

[0132] R 22_11 = R- R 12 -R 22 -(R) 11 + R 12_11 )

[0133] Furthermore, after obtaining the second contact resistance R 22_11 Subsequently, by adjusting the temperature and humidity of the spaces containing the positive and negative electrodes, the second contact resistance R of the positive and negative electrodes under different temperatures and humidity conditions can be obtained. 22_11 .

[0134] Furthermore, by adjusting the pressure applied to the aforementioned extruded positive electrode 101, central insulating sheet 32, and negative electrode 201, the second contact resistance R can be obtained. 22_11 As the pressure changes.

[0135] Third Embodiment

[0136] As shown in Figure 1 and Figure 5 As shown, the method for measuring the contact resistance of the electrode plates may include: step S110: obtaining the total resistance R between the positive electrode plate 10 and the negative electrode plate 20.

[0137] Unlike the first embodiment, in the third embodiment, the positive active material in the middle region of the positive electrode needs to be stripped. This will be explained below with reference to Figure 1 and... Figure 5 Provide a detailed description.

[0138] In the third embodiment, the electrode contact resistance to be measured can be the third contact resistance R formed by the contact between the positive electrode current collector 12 and the negative electrode active material 21. 12_21 .

[0139] To obtain the total resistance R, the positive electrode 10 and the negative electrode 20 can be pre-processed to obtain the positive electrode processed electrode 101 and the negative electrode processed electrode 201.

[0140] Specifically, pre-processing the positive electrode 10 and the negative electrode 20 may include: peeling off the positive active material 11 from the edge region of the positive electrode 10 to expose the positive current collector 12, which can be connected to one end of the resistance measuring device. Similarly, peeling off the negative active material 21 from the edge region of the negative electrode 20 to expose the negative current collector 22, which can be connected to the other end of the resistance measuring device.

[0141] like Figure 5 As shown, the positive active material 11 on the right side of the positive electrode 10 can be peeled off, thereby exposing the positive current collector 12 on the right side of the positive electrode 10. Furthermore, the negative active material 21 on the left side of the negative electrode 20 can be peeled off, thereby exposing the negative current collector 22 on the left side of the negative electrode 20. Furthermore, both the exposed positive current collector 12 and negative current collector 22 can be used to connect to the clamps of a resistance measuring device.

[0142] Furthermore, the pretreatment of the positive electrode 10 may include: stripping the positive active material 11 from the middle region of the positive electrode 10 so that at least part of the positive current collector 12 is exposed in the middle region of the positive electrode 10.

[0143] After pre-treating the positive electrode 10 and the negative electrode 20, the positive electrode treated electrode 101 and the negative electrode treated electrode 201 can be obtained.

[0144] Further, in step S112, along the thickness direction H of the electrode (e.g.) Figure 5 (From bottom to top) the bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201 and the top insulating sheet 33 are stacked together in sequence.

[0145] Furthermore, when stacking the positive electrode processing plate 101 and the central insulating plate 32, the exposed positive current collector 12 in the middle region of the positive electrode processing plate 101 is positioned opposite to the through hole 321 of the central insulating plate 32.

[0146] It is necessary to understand that Figure 5 The positive electrode active material 11 on both the upper and lower sides of the positive electrode current collector 12 shown in the figure is stripped off. In practice, when projected in the thickness direction H, it is only necessary to ensure that the exposed positive electrode current collector 12 at least partially overlaps with the projection of the through hole 321. For example, the central insulating sheet may include an insulating region 322 (such as...). Figure 5 (as shown) and through hole 321. Projected in the thickness direction H, the projection of the positive current collector 12 exposed in the middle region of the positive electrode processing electrode 101 can fall entirely into the projection of the through hole 321, the projection of the positive current collector 12 exposed in the middle region can partially fall into the insulating region 322, and the rest falls into the projection of the through hole 321.

[0147] It should be understood that the aforementioned bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape. For example, the stacked bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape.

[0148] Step S113: Measure the resistance between the positive electrode 101 and the negative electrode 201 to obtain the total resistance R.

[0149] Specifically, the clamps of the resistance measuring device can be clamped onto the exposed positive current collector 12 and negative current collector 22 located at the edge region, respectively. It should be understood that the clamps of the aforementioned resistance measuring device can be clamped onto the positive current collector 12 and negative current collector 22 before the top insulating sheet 33 is pressed.

[0150] After clamping, it can be aligned along the thickness direction H of the electrode (e.g., ...). Figure 5 The bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201, and the top insulating sheet 33 are pressed together in a downward direction, so that the negative electrode active material 21 can pass through the through hole 321 and contact the positive electrode current collector 12.

[0151] It is understandable that at this time, one end of the aforementioned resistance measuring device can form a path with the other end of the resistance measuring device through the clamp, the positive current collector 12, the negative active material 21 in contact with the positive current collector 12, the negative current collector 22, and the clamp. At this time, the resistance measured by the resistance measuring device can be the total resistance R.

[0152] It is understood that in this embodiment, the total resistance R may include: the positive current collector resistance R of the positive current collector 12.12 The negative current collector resistor R of negative current collector 22 22 The negative electrode active resistance R of negative electrode active material 21 21 The negative electrode contact resistance R between the negative electrode current collector 22 and the negative electrode active material 21 22_21 And the third contact resistance R between the positive current collector 12 and the negative active material 21 12_21 .

[0153] Further, in step S120, the internal resistance is obtained. Specifically, in this embodiment, obtaining the internal resistance may include obtaining the negative electrode active resistance R. 21 Contact resistance R with negative electrode 22_21 The sum of these values ​​yields the positive current collector resistor R. 12 And obtain the negative current collector resistor R 22 The methods for obtaining internal resistance described above have all been presented in the first embodiment and will not be repeated here.

[0154] It should be understood that, in the third embodiment, the total resistance R and the internal resistance have the following relationship:

[0155] R = R 12 +R 22 + R 21 + R 22_21 + R 12_21

[0156] The total resistance R and the positive current collector resistance R were measured. 12 Negative current collector resistor R 22 Negative electrode active resistor R 21 Contact resistance R with negative electrode 22_21 After summing, the third contact resistance R 12_21 It can be calculated using the following formula:

[0157] R 12_21 = R- R 12 -R 22 -(R) 21 + R 22_21 )

[0158] After obtaining the third contact resistance R 12_21 Then, by adjusting the temperature and humidity of the space where the positive and negative electrodes are located, the third contact resistance R of the positive and negative electrodes under different temperatures and humidity conditions can be obtained. 12_21 .

[0159] Furthermore, by adjusting the pressure applied to the aforementioned extruded positive electrode 101, central insulating sheet 32, and negative electrode 201, the third contact resistance R can be obtained. 12_21 As the pressure changes.

[0160] Fourth embodiment

[0161] As shown in Figure 1 and Figure 6 As shown, the method for measuring the contact resistance of the electrode plates may include: step S110, obtaining the total resistance R between the positive electrode plate 10 and the negative electrode plate 20.

[0162] Unlike the first embodiment, in the fourth embodiment, the negative active material in the middle region of the negative electrode sheet needs to be stripped, and the positive active material in the middle region of the positive electrode sheet also needs to be stripped. The following will refer to Figure 1 and... Figure 6 Provide a detailed description.

[0163] In this embodiment, the electrode contact resistance to be measured can be the fourth contact resistance R formed by the contact between the positive current collector 12 and the negative current collector 22. 12_22 .

[0164] To obtain the total resistance R, the positive electrode 10 and the negative electrode 20 can be pre-processed to obtain the positive electrode processed electrode 101 and the negative electrode processed electrode 201.

[0165] Specifically, pre-processing the positive electrode 10 and the negative electrode 20 may include: peeling off the positive active material 11 from the edge region of the positive electrode 10 to expose the positive current collector 12, which can be connected to one end of the resistance measuring device. Similarly, peeling off the negative active material 21 from the edge region of the negative electrode 20 to expose the negative current collector 22, which can be connected to the other end of the resistance measuring device.

[0166] like Figure 6 As shown, the positive active material 11 on the right side of the positive electrode 10 can be peeled off, thereby exposing the positive current collector 12 on the right side of the positive electrode 10. Furthermore, the negative active material 21 on the left side of the negative electrode 20 can be peeled off, thereby exposing the negative current collector 22 on the left side of the negative electrode 20. Furthermore, both the exposed positive current collector 12 and negative current collector 22 can be used to connect to the clamps of a resistance measuring device.

[0167] Furthermore, the pretreatment of the positive electrode 10 may include: stripping the positive active material 11 from the middle region of the positive electrode 10 so that at least part of the positive current collector 12 is exposed in the middle region of the positive electrode 10.

[0168] Pre-treatment of the negative electrode 20 may include: stripping the negative electrode active material 21 from the middle region of the negative electrode 20 so that at least part of the negative electrode current collector 22 is exposed in the middle region of the negative electrode 20.

[0169] After pre-treating the positive electrode 10 and the negative electrode 20, the positive electrode treated electrode 101 and the negative electrode treated electrode 201 can be obtained.

[0170] Further, in step S112, along the thickness direction H of the electrode (e.g.) Figure 6 (From bottom to top) the bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201 and the top insulating sheet 33 are stacked together in sequence.

[0171] Furthermore, when stacking the positive electrode 101, the central insulating sheet 32, and the negative electrode 201, the exposed positive current collector 12 in the middle region of the positive electrode 101, the through hole 321 in the central insulating sheet 32, and the exposed negative current collector 22 in the middle region of the negative electrode 201 are all arranged opposite to each other.

[0172] It is necessary to understand that Figure 6 The positive active material 11 on both the upper and lower sides of the positive current collector 12 shown in the figure has been stripped off, and the negative active material 21 on both the upper and lower sides of the negative current collector 22 has been stripped off.

[0173] In practice, when projecting along the thickness direction H, it is only necessary to ensure that the exposed positive current collector 12 at least partially overlaps with the projection of the through hole 321 and the projection of the negative current collector 22.

[0174] It should be understood that the aforementioned bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape. For example, the stacked bottom insulating sheet 31, positive electrode treated sheet 101, center insulating sheet 32, negative electrode treated sheet 201, and top insulating sheet 33 can be fixed together with tape.

[0175] Step S113: Measure the resistance between the positive electrode 101 and the negative electrode 201 to obtain the total resistance R.

[0176] Specifically, the clamps of the resistance measuring device can be clamped onto the exposed positive current collector 12 and negative current collector 22 located at the edge region, respectively. It should be understood that the clamps of the aforementioned resistance measuring device can be clamped onto the positive current collector 12 and negative current collector 22 before the top insulating sheet 33 is pressed.

[0177] After clamping, it can be aligned along the thickness direction H of the electrode (e.g., ...). Figure 6The bottom insulating sheet 31, the positive electrode treatment sheet 101, the center insulating sheet 32, the negative electrode treatment sheet 201, and the top insulating sheet 33 are pressed together in a downward direction, so that the negative current collector 22 can pass through the through hole 321 and contact the positive current collector 12.

[0178] It is understandable that at this time, one end of the aforementioned resistance measuring device can form a path with the other end of the resistance measuring device through the clamp, the positive current collector 12, the negative current collector 22 in contact with the positive current collector 12, and the clamp. At this time, the resistance measured by the resistance measuring device can be the total resistance R.

[0179] It is understood that in this embodiment, the total resistance R may include: the positive current collector resistance R of the positive current collector 12. 12 The negative current collector resistor R of negative current collector 22 22 And the fourth contact resistance R between the positive current collector 12 and the negative current collector 22 12_22 .

[0180] Further, in step S120, the internal resistance is obtained. Specifically, in this embodiment, obtaining the internal resistance may include obtaining the positive current collector resistor R. 12 Obtain the negative current collector resistor R 22 The methods for obtaining internal resistance described above have all been presented in the first embodiment and will not be repeated here.

[0181] It is understandable that the measured internal resistance may include: the positive current collector resistor R. 12 Negative current collector resistor R 22 .

[0182] It should be understood that, in the fourth embodiment, the total resistance R and the internal resistance have the following relationship:

[0183] R = R 12 +R 22 + R 12_22

[0184] The total resistance R and the positive current collector resistance R were measured. 12 Negative current collector resistor R 22 Next, the fourth contact resistance R 12_22 It can be calculated using the following formula:

[0185] R 12_22 = R- R 12 -R 22

[0186] After obtaining the fourth contact resistance R 12_22Then, by adjusting the temperature and humidity of the space where the positive and negative electrodes are located, the fourth contact resistance R of the positive and negative electrodes under different temperatures and humidity conditions can be obtained. 12_22 .

[0187] Furthermore, by adjusting the pressure applied to the aforementioned extruded positive electrode 101, central insulating sheet 32, and negative electrode 201, the fourth contact resistance R can be obtained. 12_22 As the pressure changes.

[0188] like Figure 11 As shown, embodiments of this application also provide an apparatus for measuring electrode contact resistance. The apparatus includes a housing, and a measuring cavity 1 is formed inside the housing. The method for measuring electrode contact resistance according to this application is performed inside the measuring cavity 1.

[0189] It should be understood that a temperature measuring component T, such as a thermometer, can be installed inside the measuring chamber 1. This temperature measuring component T can be used to obtain the temperature inside the measuring chamber 1. Similarly, a humidity measuring component RH, such as a hygrometer, can be installed inside the measuring chamber 1. This humidity measuring component RH can be used to obtain the humidity inside the measuring chamber 1.

[0190] Furthermore, a temperature regulation device and a humidity regulation device can be installed inside or outside the measuring cavity 1 to adjust the temperature and humidity inside the measuring cavity 1.

[0191] It is understandable that by obtaining the temperature and humidity inside the measuring cavity 1 and adjusting the temperature and humidity inside the measuring cavity 1, it is easier to obtain the relationship between contact resistance and temperature and humidity later.

[0192] Optionally, the device also includes a resistance measuring device 5, which can be used to measure the resistance of the component under test within the measuring cavity 1.

[0193] Optionally, a base 4 is provided inside the measuring chamber 1 for placing the positive electrode 10 and / or the negative electrode 20; a pressure block 41 is provided above the base 4, and the pressure block 41 can move along the thickness direction H of the electrode to compress the positive electrode and / or the negative electrode. The pressure block 41 can be connected to a drive mechanism to adjust the pressure of the pressure block 41, and the drive mechanism can be installed inside or outside the measuring chamber 1.

[0194] It should be understood that the output pressure of the pressure block 41 is adjustable, and the relationship between contact resistance and pressure can be obtained by adjusting the output pressure of the pressure block 41.

[0195] Furthermore, such as Figure 12As shown, curve 1 illustrates the change in contact resistance with pressure at temperature T1 and humidity RH1, and curve 2 illustrates the change in contact resistance with pressure at temperature T2 and humidity RH2. It is important to understand that T1, RH1, T2, and RH2 satisfy the following relationship:

[0196] T1 < T2, RH1 < RH2

[0197] That is, the temperature T1 in the measuring chamber 1 corresponding to curve 1 is less than the temperature T2 in the measuring chamber 1 corresponding to curve 2, and the humidity RH1 in the measuring chamber 1 corresponding to curve 1 is less than the humidity RH2 in the measuring chamber 1 corresponding to curve 2.

[0198] from Figure 12 As can be seen, under the same pressure, when the temperature is T1 and the humidity is RH1, the corresponding electrode contact resistance is less than that when the temperature is T2 and the humidity is RH2. Under the same pressure, the electrode contact resistance increases as both temperature and humidity increase. It should be understood that, under normal circumstances, the contact resistance increases with increasing temperature; the contact resistance also increases with increasing humidity.

[0199] Furthermore, such as Figure 12 As shown, the electrode contact resistance decreases with increasing pressure. When the pressure increases to a certain value, the electrode contact resistance remains unchanged or essentially unchanged.

[0200] It should be understood that at least some aspects or features of the above-described implementation methods, embodiments, or examples can be appropriately combined.

[0201] It is understood that, in this application, when the number of parts or components is not specifically limited, the number can be one or more, where multiple refers to two or more. For cases where the number of parts or components shown in the drawings and / or described in the specification is, for example, two, three, four, etc., this specific number is generally exemplary and not restrictive, and can be understood as multiple, i.e., two or more; however, this does not mean that this application excludes the case of one.

[0202] It should be understood that the above-described embodiments, examples, or examples are merely exemplary and are not intended to limit this application. Those skilled in the art can make various modifications and changes to the above-described embodiments, examples, or examples under the teachings of this application without departing from the scope of this application.

Claims

1. A method for measuring the contact resistance of an electrode, wherein, The electrode comprises a positive electrode (10) and a negative electrode (20), wherein, in the thickness direction (H) of the electrode, the positive electrode (10) comprises a positive active material (11), a positive current collector (12), and a positive active material (11) arranged sequentially, and the negative electrode (20) comprises a negative active material (21), a negative current collector (22), and a negative active material (21) arranged sequentially, characterized in that the method comprises: Obtain the total resistance (R) between the positive electrode (10) and the negative electrode (20); Obtain the internal resistance; where, The total resistance (R) includes the positive current collector resistance (R) of the positive current collector (12). 12 ) and the negative current collector resistance (R) of the negative current collector (22) 22 ), The total resistance (R) also includes the positive electrode active resistance (R) of the positive electrode active material (11). 11 The negative electrode active resistance (R) of the negative electrode active material (21) 21 The positive electrode contact resistance (R) between the positive electrode current collector (12) and the positive electrode active material (11) 12_11 The negative electrode contact resistance (R) between the negative electrode current collector (22) and the negative electrode active material (21) 22_21 The first contact resistance (R) between the positive electrode active material (11) and the negative electrode active material (21) and the positive electrode active material (21) 11_21 The internal resistance includes the positive active resistor (R). 11 ) and the positive electrode contact resistance (R 12_11 The sum of ) and the negative electrode active resistor (R) 21 ) and the negative electrode contact resistance (R 22_21 The sum of the positive current collector resistor (R) 12 The negative current collector resistor (R) 22 );or The total resistance (R) also includes the positive electrode active resistance (R) of the positive electrode active material (11). 11 The positive electrode contact resistance (R) between the positive electrode current collector (12) and the positive electrode active material (11) 12_11 The second contact resistance (R) between the negative electrode current collector (22) and the positive electrode active material (11) and the negative electrode current collector (22) and the positive electrode active material (11) 22_11 The internal resistance includes the positive active resistor (R). 11 ) and the positive electrode contact resistance (R 12_11 The sum of the positive current collector resistor (R) 12 The negative current collector resistor (R) 22 );or The total resistance (R) also includes the negative electrode active resistance (R) of the negative electrode active material (21). 21 The negative electrode contact resistance (R) between the negative electrode current collector (22) and the negative electrode active material (21) 22_21 The third contact resistance (R) between the positive current collector (12) and the negative active material (21) and the positive current collector (12) and the negative active material (21) 12_21 The internal resistance includes the negative electrode active resistor (R). 21 ) and the negative electrode contact resistance (R 22_21 The sum of the positive current collector resistor (R) 12 The negative current collector resistor (R) 22 );or The total resistance (R) also includes a fourth contact resistance (R) between the positive current collector (12) and the negative current collector (22). 12_22 The internal resistance includes the positive current collector resistor (R). 12 The negative current collector resistor (R) 22 ); The electrode contact resistance is obtained based on the total resistance (R) and the internal resistance; and Adjust the temperature and humidity of the space where the positive electrode (10) and the negative electrode (20) are located to obtain the electrode contact resistance under different temperatures and humidity conditions.

2. The method according to claim 1, characterized in that, The process of obtaining the total resistance (R) between the positive electrode (10) and the negative electrode (20) includes: The positive electrode (10) and the negative electrode (20) are pre-treated to obtain a positive electrode treated electrode (101) and a negative electrode treated electrode (201). Along the thickness direction (H) of the electrode, the positive electrode (101), the central insulating sheet (32) and the negative electrode (201) are stacked together in sequence, wherein the central insulating sheet (32) has a through hole (321). The resistance between the positive electrode (101) and the negative electrode (201) is measured to obtain the total resistance (R).

3. The method according to claim 2, characterized in that, The pretreatment of the positive electrode (10) and the negative electrode (20) includes: The positive active material (11) of the edge region of the positive electrode plate (10) is stripped off to expose the positive current collector (12) for connection to one end of the resistance measuring device; The negative electrode active material (21) is stripped from the edge region of the negative electrode sheet (20) to expose the negative electrode current collector (22) for connection to the other end of the resistance measuring device.

4. The method according to claim 3, characterized in that, The pretreatment of the positive electrode (10) and the negative electrode (20) further includes: The positive active material (11) in the middle region of the positive electrode sheet (10) is stripped away so that at least part of the positive current collector (12) is exposed in the middle region of the positive electrode sheet (10), and / or The negative electrode active material (21) in the middle region of the negative electrode sheet (20) is stripped off so that at least part of the negative electrode current collector (22) is exposed in the middle region of the negative electrode sheet (20).

5. The method according to claim 4, characterized in that, After the positive electrode (101), the central insulating sheet (32), and the negative electrode (201) are stacked together in sequence, The exposed positive current collector (12) in the middle region of the positive electrode plate (10) is positioned opposite to the through hole (321), and / or The exposed negative current collector (22) in the middle region of the negative electrode sheet (20) is positioned opposite to the through hole (321).

6. The method according to claim 2, characterized in that, Measuring the resistance between the positive electrode (101) and the negative electrode (201) to obtain the total resistance (R) includes: Along the thickness direction (H) of the electrode, the positive electrode (101), the central insulating sheet (32) and the negative electrode (201) stacked together are pressed together so that the positive electrode (101) and the negative electrode (201) are in contact through the through hole (321).

7. The method according to claim 2, characterized in that, The positive active resistor (R) used to obtain the internal resistance 11 ) and the positive electrode contact resistance (R 12_11 The sum includes: The two identical positive electrode plates (10) are stacked together along the thickness direction (H) of the electrode plates, with the central insulating plate (32) sandwiched between them; The electrode is pressed along the thickness direction (H) of the electrode so that the positive active material (11) of the two positive electrode sheets (10) comes into contact with each other through the through hole (321); The resistance between the positive current collectors (12) of the two positive electrode plates (10) is measured to obtain the first resistance; Based on the first resistor and the positive current collector (R) 12 ), to obtain the positive active resistor (R) 11 ) and the positive electrode contact resistance (R 12_11 ) and.

8. The method according to claim 2, characterized in that, The negative electrode active resistor (R) used to obtain the internal resistance 21 ) and the negative electrode contact resistance (R 22_21 The sum includes: The two identical negative electrode plates (20) are stacked together along the thickness direction (H) of the electrode plates, sandwiching the central insulating plate (32); The electrode is pressed along the thickness direction (H) of the electrode so that the negative electrode active material (21) of the two negative electrode electrodes (20) comes into contact with each other through the through hole (321); The resistance between the negative current collectors (22) of the two negative electrode plates (20) is measured to obtain the second resistance; Based on the second resistor and the negative current collector (R) 22 ), to obtain the negative electrode active resistor (R21) and the negative electrode contact resistor (R 22_21 ) and.

9. A device for measuring the contact resistance of an electrode, characterized in that, The device includes a housing, within which a measuring cavity (1) is formed, and the method for measuring the contact resistance of the electrode as described in any one of claims 1 to 8 is performed within the measuring cavity (1).

10. The apparatus according to claim 9, characterized in that, The measuring cavity (1) is provided with a base (4) for placing the positive electrode (10) and / or the negative electrode (20). A pressure block (41) is provided above the base (4). The pressure block (41) can move along the thickness direction (H) of the electrode to compress the positive electrode (10) and / or the negative electrode (20).

11. The apparatus according to claim 9, characterized in that, The device also includes a resistance measuring device for measuring the resistance of the component to be measured in the measuring cavity (1).

12. The apparatus according to claim 9, characterized in that, The device further includes: A temperature regulating device is used to adjust the temperature of the measuring cavity (1); A temperature measuring device for measuring the temperature of the measuring cavity (1); A humidity regulating device for adjusting the humidity of the measuring cavity (1); and A humidity measuring device for measuring the humidity of the measuring cavity (1).

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