Battery cell pole piece, battery and vehicle

Abstract

The utility model provides a battery cell pole piece, a battery and a vehicle, and relates to the technical field of lithium ion batteries. The battery cell pole piece comprises a first connecting part, a first functional part, a second functional part and a second connecting part which are arranged in sequence, the second function part comprises at least one transition section and at least one function section, the transition sections and the function sections are alternately arranged, and the function sections form bending areas; at least one of the first function part and the function section is provided with a plurality of blind holes. According to the battery cell pole piece, the battery and the vehicle, the blind hole is only formed in at least one of the first functional part and the functional section, and the transition section does not need to be punched, so that internal stress is effectively dispersed, the problems of lithium precipitation and the like are solved, the influence of punching on the energy density of the battery is reduced while the cycle life of the battery is prolonged, and the capacity of the battery for storing electric quantity is guaranteed; and the battery performance is improved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and in particular to a battery cell pole piece, a battery and a vehicle. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density and low environmental pollution, and are widely used in electric vehicles, digital products, energy storage and other fields. During the cycle of lithium-ion batteries, the pole piece expands and generates internal stress. If the internal stress is not effectively and evenly released, it will concentrate in the bending area of ​​the pole piece, resulting in purple spots, lithium precipitation and other phenomena, and bring safety risks. Therefore, it is necessary to release the internal stress.

[0003] In the prior art, holes are punched in the entire pole piece to reserve space for the pole piece to expand, thereby alleviating the effect of internal stress on the lithium-ion battery.

[0004] However, drilling holes in the entire area of ​​the electrode has a significant impact on the energy density of the lithium battery, resulting in a smaller amount of electricity stored per unit volume of the lithium-ion battery. Utility Model Content

[0005] The present application provides a battery cell electrode, a battery and a vehicle, which are used to solve the problem that the energy density of the battery is greatly affected by releasing internal stress through holes in the entire area of ​​the electrode, resulting in a smaller amount of electricity stored in a unit volume of the battery.

[0006] In a first aspect, the present application provides a battery cell electrode sheet, comprising: a first connecting portion, a first functional portion, a second functional portion, and a second connecting portion arranged in sequence;

[0007] The second functional portion includes at least one transition segment and at least one functional segment, the transition segments and the functional segments are alternately arranged, and the functional segments form a bending zone;

[0008] A plurality of blind holes are provided in at least one of the first functional portion and the functional segment.

[0009] In one possible implementation, in the battery cell electrode provided in the present application, the multiple blind holes include multiple first holes and multiple second holes, and the diameter of the first hole is greater than the diameter of the second hole.

[0010] In one possible implementation, in the battery cell electrode provided in the present application, the first holes and the second holes are arranged in an array, and the first holes and the second holes are staggered.

[0011] In one possible implementation, in the battery cell electrode provided in the present application, the ratio of the hole depth of the blind hole to the thickness of the first functional portion is greater than or equal to 1% and less than 100%.

[0012] In one possible implementation, in the battery cell electrode provided in the present application, the ratio of the total volume of the blind holes to the total volume of the first functional portion and the functional segment is greater than or equal to 1% and less than or equal to 45%.

[0013] In a possible implementation, the battery cell electrode provided by the present application has a second spacing between two adjacent rows of first holes, and the second spacing is equal to the width of the first functional portion divided by the number of rows of the first holes minus the diameter of the first holes;

[0014] There is a third spacing between two adjacent rows of second holes, and the third spacing is equal to the width of the first functional part divided by the number of rows of the second holes minus the diameter of the second holes;

[0015] There is a fourth spacing between adjacent rows of first holes and second holes, and the fourth spacing is equal to half of the second spacing minus the radius of the second hole.

[0016] In a possible implementation, in the battery cell electrode provided in the present application, the radius of the first hole is less than or equal to 150 μm;

[0017] The radius of the second hole is greater than or equal to 0.1 μm.

[0018] In a second aspect, the present application provides a battery comprising at least one of the above-mentioned battery cell pole pieces.

[0019] In a possible implementation, the battery cell electrode provided in the present application further includes an electrode ear;

[0020] The tab is connected to the first functional portion, and a first distance exists between the tab and one side of the first functional portion connected to the second functional portion, and the first distance is equal to a width of the tab.

[0021] In a third aspect, the present application provides a vehicle, comprising a vehicle body and any battery of the second aspect arranged on the vehicle body.

[0022] The cell pole piece, battery and vehicle provided by the present application, the cell pole piece includes a first connection part, a first functional part, a second functional part and a second connection part, and the first functional part and the second functional part are both arranged between the first connection part and the second connection part. Through the first functional part connected to the pole ear, after the cell pole piece is wound up, the second functional part is at least one transition section and at least one functional section, wherein the transition section is the smooth part of the second functional part after winding, and the functional section is the bent part of the second functional part. After the battery starts working, the first functional part connected to the pole ear and the bent functional section are more likely to have purple spots, lithium precipitation and other phenomena, so a plurality of blind holes are opened on at least one of the first functional part and the functional section to provide space for the expansion of the cell pole piece, thereby effectively releasing the internal stress generated during the operation of the battery, and preventing the occurrence of purple spots, lithium precipitation and other phenomena. In this way, only the blind holes are opened in the first functional part and the functional section where the internal stress is more concentrated and the lithium precipitation phenomenon is more likely to occur, rather than drilling holes in the entire area, which can effectively and evenly release the internal stress, and reduce the impact of drilling on the energy density of the cell pole piece, and ensure the ability of the cell pole piece to store electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the structure of a battery cell electrode provided in an embodiment of the present application;

[0025] Figure 2 for Figure 1 Usage status diagram;

[0026] Figure 3 for Figure 2 Schematic diagram of a part of the structure when the battery cell pole piece is wound;

[0027] Figure 4 A diagram showing the usage status of the battery cell electrode provided in an embodiment of the present application.

[0028] Description of reference numerals:

[0029] 100-battery cell pole piece;

[0030] 110- first connection portion;

[0031] 120- first functional unit;

[0032] 130- second functional section; 131- transition section; 132- functional section;

[0033] 140- second connection portion;

[0034] 150-first hole;

[0035] 160 - second hole;

[0036] 10-ear;

[0037] w - first spacing.

[0038] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0039] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0040] As shown in the background technology, during the cycle of lithium-ion batteries, dissolved substances in the electrolyte will react with lithium ions to form some irreversible compounds, which will be deposited on the battery cell pole pieces. When the compound deposition reaches a certain level, it will cause difficulty for lithium ions to migrate between the positive and negative electrodes, and then lithium precipitation and other phenomena will occur, resulting in reduced battery performance, shortened cycle life, and even possible consequences such as combustion and explosion. For wound batteries, the pole piece expands to produce internal stress. If the internal stress is not effectively released, it will be concentrated in the bending area, resulting in a decrease in the electrolyte content in this area, an increase in the polarization of the electrochemical reaction, and faster compound deposition, resulting in lithium precipitation and other phenomena in this area, thereby further accelerating the deterioration of the battery cell pole piece performance and bringing safety risks.

[0041] In the prior art, in order to release the internal stress generated by lithium-ion batteries during the cycle process, the entire area of ​​the battery's pole piece is usually punched to reserve space for the pole piece to expand. However, this has a significant impact on the energy density of the lithium-ion battery, resulting in a smaller amount of electricity stored per unit volume of the lithium-ion battery.

[0042] In view of the above technical problems, the embodiments of the present application provide a battery cell pole piece, a battery and a vehicle, wherein the battery cell pole piece includes a first connection portion, a first functional portion, a second functional portion and a second connection portion which are arranged in sequence, wherein the first connection portion and the second connection portion are respectively located at the two ends of the battery cell pole piece, and after the battery cell pole piece is wound up, the bent portion of the second functional portion is the functional segment, and the smooth portion is the transition segment. Since the functional segment is the bending zone after the battery cell pole piece is wound up, the internal stress generated will be concentrated in the functional segment, causing the functional segment to be more prone to purple spots, lithium deposition and other phenomena, and the first functional portion is also prone to compound deposition and lithium deposition due to its connection with the pole ear. Therefore, the embodiments of the present application provide a plurality of blind holes on at least one of the first functional portion and the functional segment to provide space for the expansion of the pole piece and release the internal stress. In this way, by drilling blind holes in specific areas of the battery cell pole sheets where internal stress concentration and compound deposition are prone to occur, most of the internal stress can be effectively released, reducing its impact on battery performance and increasing the battery life. Compared with drilling holes in the entire area of ​​the battery cell pole sheet, it can also reduce the impact of drilling on the energy density of the battery cell pole sheet, thereby ensuring the amount of electricity that can be stored per unit volume of the battery.

[0043] The following specific embodiments are used to describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings:

[0044] It should be noted that the battery cell electrode provided in the embodiments of the present application can be applied to various different batteries.

[0045] See also Figures 1 to 4 As shown, the battery cell electrode 100 of the embodiment of the present application includes a first connecting portion 110, a first functional portion 120, a second functional portion 130 and a second connecting portion 140 arranged in sequence; the second functional portion 130 includes at least one transition segment 131 and at least one functional segment 132, the transition segments 131 and the functional segments 132 are alternately arranged, and the functional segments 132 form a bending zone; a plurality of blind holes are opened on at least one of the first functional portion 120 and the functional segment 132.

[0046] In the present application, the first connection portion 110 and the second connection portion 140 are respectively arranged at both ends of the battery cell pole piece 100. After the battery cell pole piece 100 is rolled up, the bent portion of the second functional portion 130 is the functional segment 132, and the smooth portion is the transition segment 131, wherein the lengths of the transition segment 131 and the functional segment 132 are not limited in the present embodiment of the application.

[0047] It should be noted that, since the functional segment 132 and the transition segment 131 are the parts corresponding to the bending area and the smooth area after the battery cell electrode 100 is wound up, and the bending area and the smooth area are arranged alternately, the number of functional segments 132 and transition segments 131 is not limited, as long as the functional segments 132 and the transition segments 131 are arranged alternately. The first functional part 120 and the second connecting part 140 are respectively connected to the two ends of the second functional part 130, which may specifically include the following four situations: first, both ends of the second functional part 130 are transition sections 131, then the first functional part 120 and the second connecting part 140 are both connected to the transition section 131; second, both ends of the second functional part 130 are functional sections 132, then the first functional part 120 and the second connecting part 140 are both connected to the functional section 132; third, the end of the second functional part 130 connected to the first functional part 120 is the transition section 131, and the end of the second functional part 130 connected to the second connecting part 140 is the functional section 132; fourth, the end of the second functional part 130 connected to the first functional part 120 is the functional section 132, and the end of the second functional part 130 connected to the second connecting part 140 is the transition section 131. The above four situations are all applicable to the battery cell electrode 100 of the embodiment of the present application.

[0048] It can be understood that when the number of transition segments 131 and functional segments 132 is large, after the battery cell electrode sheet 100 is wound up, the first connection portion 110 and the second connection portion 140 will be located inside and outside the wound battery cell, respectively. Figure 4 The cell electrode sheet 100 in FIG. 1 only shows the first functional portion 120 and the second functional portion 130 after the cell electrode sheet 100 is wound up, and the first connecting portion 110 and the second connecting portion 140 are in Figure 4 Not shown.

[0049] In the specific implementation, since the functional section 132 is a bending area, the internal stress generated by the pole piece during the cycle of the lithium-ion battery is more likely to be concentrated in the functional section 132, resulting in less electrolyte in the functional section 132, accelerated compound deposition, and then the purple spot lithium deposition and other phenomena. The first functional part 120 is connected to the pole ear 10. Since it is close to the pole ear 10, the expansion of the battery cell pole piece 100 produces more compounds, and lithium deposition is also prone to occur. Therefore, a plurality of blind holes are opened on at least one of the first functional part 120 and the functional section 132, that is, blind holes are opened in the area where the probability of lithium deposition on the battery cell pole piece 100 is higher. On the one hand, it can effectively slow down the deposition of compounds, slow down the occurrence of lithium deposition, and improve the service life of the battery. On the other hand, compared with drilling the entire area of ​​the battery cell pole piece 100, it also effectively reduces the impact of drilling on the battery energy density, and ensures the battery's ability to store electricity per unit volume. Among them, the shape of the blind hole can be circular, square or other shapes, and this embodiment does not limit this.

[0050] After the battery assembled with the cell electrode piece 100 of this embodiment is charged and discharged for 1000cl at 1C / 1C cycle at 25°C, the battery is disassembled and the interface appearance of the cell electrode piece 100 is observed. The experimental results of this embodiment and the control group are shown in the following Table 1:

[0051] Table 1 Experimental results of different pole pieces

[0052]

[0053] Among them, pole piece 1 is a control group, pole pieces 2 and pole pieces 3 are the solutions adopted in this embodiment, pole piece 1 is a non-perforated battery core pole piece 100, pole pieces 2 and pole pieces 3 are both provided with blind holes in the first functional part 120 and the functional section 132, and pole pieces 2 and pole pieces 3 are the solutions with the same blind hole arrangement mode and different blind hole radius, and the unit area is 1mm 2 , the unit area involved below is 1mm 2 As can be seen from Table 1, compared with pole piece 1, the wrinkles of pole pieces 2 and 3 are smaller, and the lithium deposition phenomenon is improved from severe lithium deposition to slight lithium deposition or good lithium deposition, that is, the blind holes opened in the first functional portion 120 and the functional segment 132 can effectively release the internal stress, and can effectively improve the lithium deposition problem of the battery cell pole piece 100, and as the radius of the blind hole increases, the improvement effect on the lithium deposition problem is more obvious.

[0054] Therefore, in the embodiment of the present application, the problem of lithium plating can be effectively improved by opening blind holes in specific areas such as the first functional part 120 and the functional segment 132 without drilling holes in the entire battery cell electrode 100, thereby ensuring the battery's ability to store electricity per unit volume and reducing the impact of drilling on energy density.

[0055] In some possible implementations, see Figure 1 , Figure 2 and Figure 3 As shown, the plurality of blind holes in the embodiment of the present application include a plurality of first holes 150 and a plurality of second holes 160 , and the diameter of the first holes 150 is greater than the diameter of the second holes 160 .

[0056] It can be seen from Table 1 that the larger the radius of the blind hole, the more obvious the improvement effect on the lithium plating problem. However, if all the blind holes on the battery cell electrode 100 are of the same size and have a large radius, large gaps will be generated between the blind holes, resulting in uneven internal stress distribution and slight wrinkles on the electrode.

[0057] It can be understood that the blind holes are set as multiple first holes 150 and multiple second holes 160, and the diameter of the first hole 150 is larger than the diameter of the second hole 160. In this way, increasing the diameter of the first hole 150 and filling the gaps between the first holes 150 with the second hole 160 can make the internal stress distribution more uniform, effectively slowing down the deformation or damage rate of the battery cell electrode 100.

[0058] Among them, since the embodiment of the present application does not limit the shape of the first hole 150 and the second hole 160, the first hole 150 and the second hole 160 can be circular or square, oval or other shapes, so the diameter and radius of the first hole 150 and the second hole 160 in the embodiment of the present application are equivalent diameters and equivalent radii. Equivalent diameters and equivalent radii refer to calculating the area of ​​the hole, equating the area of ​​the hole to the area of ​​a circle, and then calculating the diameter or radius of the circle, which is the equivalent diameter or equivalent radius.

[0059] In some possible implementations, see Figure 1 , Figure 2 and Figure 3 As shown, the first holes 150 and the second holes 160 of the embodiment of the present application are arranged in an array, and the first holes 150 and the second holes 160 are staggered.

[0060] In some embodiments, the first holes 150 and the second holes 160 are arranged in an array, and the first holes 150 and the second holes 160 can be staggered, for example, a second hole 160 is arranged between every four first holes 150 in a circle to fill the gap, thereby distributing the stress more evenly and improving the structural strength of the battery cell pole piece 100. In addition, the staggered arrangement of the first holes 150 and the second holes 160 can also strengthen the structural strength of the battery cell pole piece 100, improve its toughness, and prevent the battery cell pole piece 100 from deformation or damage.

[0061] After the battery assembled with the cell electrode piece 100 of this embodiment is charged and discharged for 1000cl at 1C / 1C cycle at 25°C, the battery is disassembled and the interface appearance of the cell electrode piece 100 is observed. The experimental results of this embodiment and the control group are shown in the following Table 2:

[0062] Table 2 Experimental results of different pole pieces

[0063]

[0064] Among them, pole piece 2 is the control group, pole piece 4, pole piece 5, pole piece 6 and pole piece 7 are all the schemes adopted in this embodiment, pole piece 2 only has a plurality of first holes 150, pole piece 4, pole piece 5, pole piece 6 and pole piece 7 all have a plurality of first holes 150 and second holes 160, and the first holes 150 and second holes 160 are arranged in an array, the difference between pole piece 4 and pole piece 5 is only that the number of second holes 160 per unit area of ​​pole piece 5 is more than the number of second holes 160 per unit area of ​​pole piece 4, the difference between pole piece 5 and pole piece 6 is only that the number of first holes 150 per unit area of ​​pole piece 6 is deeper than the first holes 150 per unit area of ​​pole piece 5, the difference between pole piece 6 and pole piece 7 is only that the first hole 150 and the second hole 160 of pole piece 6 are both circular, the first hole 150 and the second hole 160 of pole piece 7 are both square, and the radius of the first hole 150 and the second hole 160 of pole piece 7 is an equivalent radius.

[0065] It can be seen from Table 2 that after a plurality of first holes 150 and a plurality of second holes 160 are simultaneously opened in the first functional portion 120 and the functional segment 132, and the first holes 150 and the second holes 160 are arranged in an array, and the first holes 150 and the second holes 160 are staggered, the pole piece no longer has wrinkles, and the interface is good, that is, the internal stress is more evenly distributed, and increasing the number of first holes 150 and second holes 160 per unit area can improve the effect of improving purple spots and lithium precipitation problems. In addition, according to pole pieces 7 and 8, it can be seen that the shapes of the first holes 150 and the second holes 160 have an impact on the effect of improving purple spots and lithium precipitation problems, and circular holes have a better improvement effect.

[0066] In some possible implementations, see Figure 1 As shown, the ratio of the hole depth of the blind hole in the embodiment of the present application to the thickness of the first functional portion 120 is greater than or equal to 1% and less than 100%.

[0067] It should be noted that since the battery cell pole piece 100 is a complete sheet structure, the thicknesses of the first connecting part 110, the first functional part 120, the second functional part 130 and the second connecting part 140 are all the same, so the thickness of the first functional part 120 is the thickness of the battery cell pole piece 100, and the ratio of the hole depth of the blind hole to the thickness of the first functional part 120 is the hole depth ratio. The hole depth ratios of the first hole 150 and the second hole 160 should both be between 1% and 100% to ensure that the first hole 150 and the second hole 160 release stress and improve the lithium precipitation effect. If the hole depth ratio is less than 1%, the hole is too shallow and the effect is difficult to achieve. Since the first hole 150 and the second hole 160 are both blind holes, the hole depth ratio should be less than 100%.

[0068] After the battery assembled with the cell pole pieces 100 with different blind hole depth ratios was charged and discharged for 1000cl at 1C / 1C cycle at 25°C, the battery was disassembled and the interface appearance of the cell pole pieces 100 was observed. The experimental results of the cell pole pieces 100 with different hole depth ratios are shown in Table 3 below:

[0069] Table 3 Experimental results of different pole pieces

[0070]

[0071] Among them, only one blind hole with one radius is opened on the pole piece 3 and the pole piece 8, and the difference between the two is that the hole depth ratio of the blind hole is different. It can be seen from Table 3 that when the hole depth is equal to 100%, the improvement effect of the hole on lithium deposition and purple spots will be affected, so the hole depth ratio of the blind hole needs to be less than 100%.

[0072] In some possible implementations, see Figure 1 As shown, the ratio of the total volume of the blind holes in the embodiment of the present application to the total volume of the first functional portion 120 and the functional segment 132 is greater than or equal to 1% and less than or equal to 45%.

[0073] In specific implementation, whether the preset blind hole depth, number of blind holes and radius of blind holes can effectively improve lithium deposition can be judged based on the ratio of the total volume of the blind holes to the total volume of the functional segment 132 of the first functional part 120, that is, the pore volume proportion of the blind holes. The pore volume proportion of the blind holes should be between 1% and 45%.

[0074] Specifically, it can be judged by the following formula:

[0075]

[0076] Wherein, N is the number of the first holes 150 per unit area, P is the hole volume ratio of the blind hole, and n is the number of the second holes 160 per unit area. is the hole depth ratio of the first hole 150 , θ is the hole depth ratio of the second hole 160 , R is the hole radius of the first hole 150 , and r is the hole radius of the second hole 160 .

[0077] When punching the first functional portion 120 and the functional segment 132, the preset value is substituted into the above formula for preliminary calculation. If the hole volume proportion P of the obtained blind hole is greater than or equal to 1% and less than or equal to 45%, it proves that the preset value is reasonable. If it is not within the range, it is necessary to reset the preset value for calculation.

[0078] A battery composed of multiple groups of cell pole pieces 100 with different preset values ​​resulting in different blind hole volume ratios was assembled. After 1000cl of 1C / 1C cycle charge and discharge at 25°C, the battery was disassembled and the interface appearance of the cell pole piece 100 was observed. The experimental results of different pole pieces are shown in Table 4 below:

[0079] Table 4 Experimental results of different pole pieces

[0080]

[0081] Continuation table:

[0082]

[0083] Among them, pole piece 2, pole piece 3, pole piece 4, pole piece 5, pole piece 6, pole piece 8, pole piece 9, and pole piece 10 all use different hole depth ratios, hole radiuses, and the number of holes per unit area, and obtain different pore volume ratios P. It can be seen from Table 4 that when the pore volume ratio P is between 1% and 45, the improvement effects of the battery cell pole piece 100 on lithium precipitation, purple spots, etc. are different, but they are all improved. According to the experimental results of pole piece 10, it can be seen that when the pore volume ratio P of the blind hole approaches the critical value of 45%, a slight demoulding phenomenon has begun to appear, that is, the bonding force between the material area and the foil in the punching area decreases. If the pore volume ratio P continues to increase, the battery cell pole piece 100 may not be used or have poor performance. Therefore, the pore volume ratio P needs to be controlled within the range of 1% to 45%.

[0084] In some possible implementations, see Figure 1 As shown, there is a second spacing between two adjacent rows of first holes 150 in the embodiment of the present application, and the second spacing is equal to the width of the first functional part 120 divided by the number of rows of the first holes 150 minus the diameter of the first holes 150; there is a third spacing between two adjacent rows of second holes 160, and the third spacing is equal to the width of the first functional part 120 divided by the number of rows of the second holes 160 minus the diameter of the second holes 160; there is a fourth spacing between an adjacent row of first holes 150 and a row of second holes 160, and the fourth spacing is equal to half of the second spacing minus the radius of the second holes 160.

[0085] It should be noted that when the first holes 150 and the second holes 160 are arranged in an array, the row spacing of each row of the first holes 150 remains consistent, the row spacing of each row of the second holes 160 remains consistent, and the number of rows and columns of the first holes 150 is consistent. Therefore, the square of the number of rows of the first holes 150 per unit area is equal to the number of the first holes 150. Similarly, the square of the number of rows of the second holes 160 per unit area is equal to the number of the second holes 160.

[0086] Therefore, the second and third spacings can be calculated using the following formulas:

[0087]

[0088] Among them, the length and width of the unit area are both 1000μm, D is the second spacing, N is the number of first holes 150 per unit area, R is the radius of the first hole 150, d is the third spacing, n is the number of second holes 160 per unit area, and r is the radius of the second hole 160.

[0089] In this way, the first holes 150 and the second holes 160 can be evenly arranged according to the second spacing and the third spacing, so that the staggered first holes 150 and the second holes 160 can better resist the deformation of the battery cell electrode 100, making the battery more stable and durable.

[0090] In some embodiments, in order to ensure the accuracy of the relative position between the first holes 150 and the second holes 160 , it is also necessary to calculate the spacing between an adjacent row of first holes 150 and a row of second holes 160 , that is, the fourth spacing.

[0091] The fourth spacing can be calculated according to the following formula,

[0092] Δd=D / 2-r

[0093] Wherein, Δd is the fourth distance, D is the second distance, and r is the radius of the second hole 160 .

[0094] In some possible implementations, see Figure 1 As shown, the radius of the first hole 150 in the embodiment of the present application is less than or equal to 150 μm; the radius of the second hole 160 is greater than or equal to 0.1 μm.

[0095] In the specific implementation, if the radius of the second hole 160 is too small, the internal stress will not be uniformly distributed. Therefore, the radius of the second hole 160 should be greater than or equal to 0.1 μm. If the radius of the first hole 150 is too large, the structural strength of the battery cell electrode 100 will be destroyed, causing the battery to be easily deformed or damaged. Therefore, the radius of the first hole 150 should be less than or equal to 150 μm.

[0096] After 1000cl of 1C / 1C cycle charge and discharge at 25°C for 1000cl, the battery was disassembled and the interface appearance of the cell electrode 100 was observed. The experimental results of different electrode pieces are shown in Table 5 below:

[0097] Table 5 Experimental results of different pole pieces

[0098]

[0099] Among them, the pore volume proportion P of the pole piece 5, the pole piece 11 and the pole piece 12 are all in the range of 1% to 45%, and the difference between the three is only the different radius of the first hole 150 and the different number of first holes 150 per unit area caused by the different radius of the first hole 150. It can be seen from Table 5 that when the radius of the first hole 150 is greater than 150μm, the area where the blind hole of the battery cell pole piece 100 begins will have a serious demolding phenomenon, making the battery unusable, and when the radius of the first hole 150 is less than or equal to 150μm, the structural strength of the battery cell pole piece 100 is good and the improvement effect on lithium precipitation and purple spots is good, so it is necessary to control the radius of the first hole 150 within 150μm.

[0100] See also Figure 1 , Figure 3 and Figure 4 As shown, an embodiment of the present application further provides a battery, comprising at least one of any of the above-mentioned battery cell pole pieces 100.

[0101] Among them, the structure and working principle of the battery cell electrode 100 are described in detail in the above embodiments, and will not be repeated here.

[0102] In a specific implementation, when winding the battery cell pole piece 100, one of the first connection part 110 and the second connection part 140 of the battery cell pole piece 100 is connected to the winding needle. After the winding is completed, the winding needle is pulled out, and the other of the first connection part 110 and the second connection part 140 is fixed to the wound state by means of glue, tape and other components. The battery made of the above-mentioned battery cell pole piece 100 has good structural strength and is not easy to deform or damage, and the problems such as lithium deposition and purple spots are improved, thereby effectively improving the performance of the battery and extending the cycle life of the battery. In addition, since the battery cell pole piece 100 is only punched in specific areas, while ensuring the battery performance, the energy density of the battery is less affected by the punching, and the amount of electricity that can be stored per unit volume of the battery is higher.

[0103] In some possible implementations, see Figure 1 and Figure 2 As shown, the embodiment of the present application also includes a tab 10 , which is connected to the first functional portion 120 , and a first spacing w is provided between the tab 10 and one side of the first functional portion 120 connected to the second functional portion 130 , and the first spacing w is equal to the width of the tab 10 .

[0104] In some embodiments, the pole tab 10 is arranged on the first functional part 120, one side of the first functional part 120 is connected to the first connecting part 110, and the other side of the first functional part 120 is connected to the second functional part 130, and the first spacing w between the side where the first functional part 120 and the second functional part 130 are connected and the pole tab 10 should be equal to the width of the pole tab 10, so that the range covered by the first functional part 120 is an area where lithium plating is more serious. Drilling in this area can effectively improve lithium plating and improve the performance of the battery.

[0105] See also Figure 1 As shown, an embodiment of the present application also provides a vehicle, comprising a vehicle body and any of the above-mentioned batteries arranged on the vehicle body.

[0106] It can be understood that after installing the above-mentioned battery on the vehicle body, the battery is not prone to deformation, lithium deposition and other problems, and has high safety. The energy storage of the battery is less affected by the punching of the battery cell electrode 100, and the energy density of the battery is relatively high. Therefore, while ensuring the safety performance of the vehicle, the ability of the vehicle battery to store electricity is improved, which is beneficial to extending the vehicle's cruising range.

[0107] In summary, the battery cell pole piece 100 provided in the embodiment of the present application has a plurality of blind holes on at least one of the functional sections 132 of the first functional section 120 and the second functional section 130 thereof, and the plurality of blind holes include a plurality of first holes 150 and a plurality of second holes 160, and the radius of the first hole 150 is greater than the radius of the second hole 160, so that the first holes 150 and the second holes 160 are arranged in an array and staggered. In this way, by opening the first holes 150 and the second holes 160 in a specific area, the internal stress can be effectively and evenly released, the phenomenon of purple spots and lithium precipitation can be improved, the structural strength of the battery cell pole piece 100 can be enhanced, and the deformation or damage thereof can be prevented. At the same time, no blind holes are opened in each transition section 131, which reduces the influence of drilling on the energy density of the battery and ensures the battery's ability to store electricity.

[0108] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0109] In the embodiments of the present application, the devices or elements referred to or implied must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present application. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise precisely and specifically specified.

[0110] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0111] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0112] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0113] It can be understood that in the embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0114] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0115] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A battery cell electrode, characterized in that: It includes a first connecting portion, a first functional portion, a second functional portion and a second connecting portion which are arranged in sequence; The second functional portion includes at least one transition segment and at least one functional segment, the transition segments and the functional segments are alternately arranged, and the functional segments form a bending zone; A plurality of blind holes are provided in at least one of the first functional portion and the functional segment.

2. The battery cell electrode according to claim 1, characterized in that: The plurality of blind holes include a plurality of first holes and a plurality of second holes, wherein a diameter of the first holes is greater than a diameter of the second holes.

3. The battery cell electrode according to claim 2, characterized in that: The first holes and the second holes are arranged in an array, and the first holes and the second holes are staggered.

4. The battery cell electrode according to any one of claims 1 to 3, characterized in that: A ratio of a hole depth of the blind hole to a thickness of the first functional portion is greater than or equal to 1% and less than 100%.

5. The battery cell electrode according to any one of claims 1 to 3, characterized in that: A ratio of a total volume of the blind holes to a total volume of the first functional portion and the functional segment is greater than or equal to 1% and less than or equal to 45%.

6. The battery cell electrode according to claim 3, characterized in that: There is a second spacing between two adjacent rows of the first holes, and the second spacing is equal to the width of the first functional part divided by the number of rows of the first holes minus the diameter of the first holes; There is a third spacing between two adjacent rows of the second holes, and the third spacing is equal to the width of the first functional part divided by the number of rows of the second holes minus the diameter of the second holes; There is a fourth spacing between adjacent rows of the first holes and adjacent rows of the second holes, and the fourth spacing is equal to half of the second spacing minus the radius of the second hole.

7. The battery cell electrode according to claim 2, characterized in that: The radius of the first hole is less than or equal to 150 μm; The radius of the second hole is greater than or equal to 0.1 μm.

8. A battery, characterized in that: Comprising at least one battery cell electrode sheet according to any one of claims 1 to 7.

9. The battery according to claim 8, characterized in that It also includes the extreme ears; The tab is connected to the first functional portion, and a first distance exists between the tab and one side of the first functional portion connected to the second functional portion, and the first distance is equal to a width of the tab.

10. A vehicle, characterized in that: The invention comprises a vehicle body and the battery according to claim 8 or 9 arranged on the vehicle body.

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