Electrode assembly and battery cell

Abstract

The utility model discloses an electrode assembly and a battery cell. The electrode assembly provided by the utility model comprises a pole piece, a pole lug and a conductive adhesive, the pole piece comprises a current collector and an active substance layer, the active substance layer is connected to the current collector, the current collector comprises a blank area, and the blank area is exposed outside the active substance layer. The tab comprises a first section and a second section which are connected with each other, the first section is connected to the blank area, and the first section is provided with a glue groove. The conductive adhesive is arranged in the adhesive groove and is connected with the first section and the blank area. According to the connection mode in the prior art, a tab and a pole piece are bonded through a conductive adhesive, and the size of the connection position in the thickness direction is the sum of the sizes of the connection position of the pole piece, the conductive adhesive and the tab in the thickness direction, however, according to the electrode assembly, the empty groove is formed in the connection position of the tab and the pole piece, the conductive adhesive is arranged in the empty groove, and the conductive adhesive is arranged in the empty groove; therefore, the occupied space of the conductive adhesive in the thickness direction can be reduced, the space utilization rate is improved, and the energy density is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electric core manufacturing, specifically relates to an electrode assembly and electric core. BACKGROUND

[0002] The tab in the electric core is the metal conductor that leads the current in the battery, and is also the contact point when the battery charges and discharges. They are responsible for connecting the electrical energy inside the battery with the external circuit, thereby realizing the charging and discharging function of the battery. The connection mode of the tab and the pole piece in the prior art adopts the method of using conductive glue to bond the tab and the pole piece. Thus, only one side of the bonding position needs to be left white, which improves the utilization rate and energy density of the pole piece. However, the conductive glue itself also has a thickness, so the conductive glue itself also occupies the space inside the electric core, thereby reducing the energy density of the electric core. SUMMARY

[0003] The utility model aims at at least solving one of the technical problems existing in the prior art. To this end, the utility model provides an electrode assembly capable of improving the energy density.

[0004] The utility model further provides an electric core with the above electrode assembly.

[0005] The electrode assembly according to the first aspect of the utility model comprises a pole piece, a tab and conductive glue. The pole piece comprises a current collector and an active material layer, the active material layer is connected to the current collector, the current collector comprises a blank area, and the blank area is exposed outside the active material layer. The tab comprises a first segment and a second segment connected to each other, the first segment is connected to the blank area, and the first segment is provided with a glue groove. The conductive glue is arranged in the glue groove, and the conductive glue connects the first segment and the blank area.

[0006] The electrode assembly according to the utility model embodiment has at least the following beneficial effects: the connection mode in the prior art is to bond the tab and the pole piece through conductive glue, the size of the connection in the thickness direction is the sum of the sizes of the pole piece, the conductive glue and the connection of the tab in the thickness direction, and the electrode assembly of the utility model sets up a hollow groove at the connection of the tab and the pole piece, and arranges the conductive glue in the hollow groove. Thus, compared with the prior art, the electrode assembly can reduce the occupied space of the conductive glue in the thickness direction, thereby improving the space utilization and the energy density.

[0007] According to some embodiments of the present application, the first section comprises a body part and a protruding part connected to each other, the protruding part protrudes towards the surface of the blank area relative to the body part, one end of the protruding part away from the body part is in contact with the blank area, and the glue groove is formed in the protruding part.

[0008] According to some embodiments of the present application, the total area of the first section is S1, the total area of the glue groove is S2, and 0.7*S1

[0009] According to some embodiments of the present application, the thickness of the first section is H1, the depth of the glue groove is H2, and 0.3*H1

[0010] According to some embodiments of the present application, a plurality of glue grooves are provided, the glue grooves are annular, and the plurality of glue grooves are concentrically and spacedly arranged.

[0011] According to some embodiments of the present application, a plurality of glue grooves are provided, the glue grooves are rectangular, and the plurality of glue grooves are arranged in a rectangular array.

[0012] According to some embodiments of the present application, a plurality of glue grooves are provided, the glue grooves are straight strip grooves, the glue grooves pass through both ends of the first section along the length direction, and the plurality of glue grooves are spacedly arranged along the width direction of the first section.

[0013] According to some embodiments of the present application, the thickness of the first section is smaller than the thickness of the second section, and the first section and the second section jointly define at least one stepped groove. When the tab size is too large, it will occupy more space inside the battery cell, which means that the active material for storing electrical energy will decrease under the same battery cell volume, resulting in a corresponding decrease in the volume energy density of the battery cell. However, a tab size that is too small will adversely affect the current transmission efficiency, heating and short circuit risk, battery performance and life, and manufacturing and assembly difficulty of the battery cell. The thickness of the first section is smaller than the thickness of the second section, which thins the first section connecting the tab and the pole piece, while the thickness of the second section extending relative to the pole piece remains unchanged. Thus, the space occupied by the thinned part can be reduced, the energy density is improved, the size of the part in contact with the outside world is maintained, and the current transmission efficiency is sufficient to ensure the quality of the battery cell.

[0014] According to some embodiments of the present application, the thickness of the first section is D1, the thickness of the second section is D2, and 0.3 < (D1 / D2) < 0.8.

[0015] According to some embodiments of the present application, the width of the first section is greater than the width of the second section, the width of the first section is W1, the width of the second section is W2, and 0.2 < (W2 / W1) < 0.5.

[0016] According to some embodiments of the present application, the electrode assembly further comprises a tab adhesive, a first insulating layer, and a second insulating layer. The tab adhesive is connected to the second section, and the tab adhesive is distributed apart from the first section. The first insulating layer covers a side surface of the first section away from the blank area. The second insulating layer is coated on an outer surface of the second section, and the second insulating layer is located between the tab adhesive and the first section.

[0017] According to the battery cell of the second aspect of the present application, the electrode assembly of any one of the first aspect of the present application is used.

[0018] According to the battery cell of the present application, the following beneficial effects are achieved: in the prior art, the tab and the tab are connected by conductive adhesive, the size of the connection in the thickness direction is the sum of the sizes of the tab, the conductive adhesive, and the connection of the tab in the thickness direction, and in the electrode assembly of the present application, a hollow groove is formed at the connection of the tab and the tab, and the conductive adhesive is arranged in the hollow groove. Compared with the prior art, the space occupied by the conductive adhesive in the thickness direction can be reduced, the space utilization is improved, and the energy density of the battery cell using the electrode assembly can be effectively improved.

[0019] Additional aspects and advantages of the present application will be given in part in the following description, some of which will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] The present application will be further described below in conjunction with the drawings and embodiments, wherein:

[0021] Figure 1 FIG. 1 is a structural schematic diagram of an electrode assembly in the prior art;

[0022] Figure 2 FIG. 2 is a side view of an electrode assembly in the first embodiment of the present application;

[0023] Figure 3 FIG. 3 is a side view of an electrode assembly in the second embodiment of the present application;

[0024] Figure 4 FIG. 4 is a side view of an electrode assembly in the third embodiment of the present application;

[0025] Figure 5 is a plan view of the tab in the first embodiment of the present application;

[0026] Figure 6 is a plan view of the tab in the second embodiment of the present application;

[0027] Figure 7 is a plan view of the tab in the third embodiment of the present application;

[0028] Figure 8 is a plan view of the tab in the fourth embodiment of the present application;

[0029] Figure 9 is a plan view of the electrode assembly in one embodiment of the present application.

[0030] The drawing reference: electrode assembly 100, tab 101, tab 102, conductive glue 103, current collector 104, active material layer 105, blank area 106, first section 201, second section 202, glue groove 203, body part 204, convex part 205, step groove 301, tab glue 901, first insulating layer 902, second insulating layer 903. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary, only for explaining the present application, and cannot be understood as limiting the present application.

[0032] In the description of the present application, it is understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the present application. The device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0033] In the description of the present application, the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. is not included in the number, above, below, etc. is included in the number. If there is a description of the first, second, only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features.

[0034] In the description of the utility model, unless otherwise explicitly limited, the words such as setting, installing, connecting should be understood broadly, and the person skilled in the art can determine the specific meaning of the above words in the utility model according to the specific content of the technical scheme.

[0035] In the description of the utility model, the description of the reference terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0036] Reference Figure 2 According to the electrode assembly 100 of the first aspect embodiment of the utility model, the tab 102 includes the first section 201 and the second section 202 connected to each other, the first section 201 is connected to the blank area 106, and the first section 201 is provided with the glue groove 203. The conductive glue 103 is arranged in the glue groove 203, and the conductive glue 103 connects the first section 201 and the blank area 106. According to Figure 1 The connection mode in the prior art is that the tab 102 and the tab 101 are bonded through the conductive glue 103, and the size of the connection in the thickness direction is the sum of the sizes of the tab 101, the conductive glue 103 and the connection of the tab 102 in the thickness direction. The electrode assembly 100 of the utility model sets the air slot in the connection of the tab 102 and the tab 101, and sets the conductive glue 103 in the air slot, so that compared with the prior art, the conductive glue 103 can reduce the occupied space in the thickness direction, thereby improving the space utilization and the energy density.

[0037] Reference Figure 2 In some embodiments of the utility model, the first section 201 includes the body part 204 and the protruding part 205 connected to each other, the protruding part 205 protrudes relative to the surface of the body part 204 towards the blank area 106, one end of the protruding part 205 away from the body part 204 is in contact with the blank area 106, and the glue groove 203 is formed in the protruding part 205. As Figure 1In the prior art shown, the tab 102 is connected to the current collector 104 through the conductive glue 103, and in some embodiments of the utility model, the protruding part 205 is arranged to make the protruding part 205 directly contact the blank area 106 of the current collector 104, so that the conductive glue 103 can be pasted to the tab 102, and a direct contact point of the tab 102 and the current collector 104 is provided, and the conductive effect is better than that of the prior art in which the connection is only through the conductive agent.

[0038] Reference Figure 6 In some embodiments of the utility model, the total area of the first section 201 is S1, the total area of the glue groove 203 is S2, and 0.7*S1

[0039] Reference Figure 2 In some embodiments of the utility model, the thickness of the first section 201 is H1, the depth of the glue groove 203 is H2, and 0.3*H1

[0040] Reference Figure 8 In some embodiments of the utility model, the glue groove 203 is arranged in multiple numbers, and the glue groove 203 is annular, and the multiple glue grooves 203 are concentrically and spacedly arranged. Figure 8 The glue groove 203 shown is convenient to process, the outermost glue groove 203 can be first processed, and then the inner ring glue groove 203 is processed at intervals, after the conductive glue 103 is arranged in the glue groove 203, the outer glue groove 203 can well bond the first section 201 to the blank area 106, and the inner ring glue groove 203 can further consolidate and improve the stability of the tab 102 bonding, and prevent the tab 102 from falling off.

[0041] Reference Figure 6In some embodiments of the utility model, glue groove 203 is provided with multiple, glue groove 203 is rectangular, multiple glue groove 203 is rectangular array distribution. Rectangular glue groove 203 is convenient for processing, and array distribution can make tab 102 more evenly bonded to blank area 106 of current collector 104, and it is convenient to fill conductive glue 103, it needs to be explained that, in some embodiments of the utility model, the filling of conductive glue 103 is not limited in glue groove 203, can be partially arranged in glue groove 203, partially exposed in glue groove 203 and connect first section 201 with current collector 104, when setting like this, still can reduce overall size, improve the effect of energy density under the premise of the amount of conductive glue 103 fixed.

[0042] Reference Figure 7 In some embodiments of the utility model, glue groove 203 is provided with multiple, glue groove 203 is straight strip groove, glue groove 203 is through first section 201 along the length direction two ends, multiple glue groove 203 is along the width direction of first section 201 interval distribution. Through glue groove 203 is convenient for filling conductive glue 103, and after being through along the length direction, even if some overflow of filled conductive glue 103 can overflow in the part gap of blank area 106 shown in the drawing, Figure 3 Or Figure 4 Better filling of blank area 106 domain on blank area 106, improve the bonding stability of tab 102, interval distribution of glue groove 203 along the width direction of first section 201 is because the width size of first section 201 is larger, interval distribution multiple glue groove 203 can make each part of first section 201 is bonded to blank area 106 and improve the stability of tab 102, and provide good conductivity.

[0043] It needs to be explained that, in some embodiments of the utility model, the opening shape of glue groove 203 is not limited to the above structure, and can also be opened into arc, M shape and various shapes, can open single glue groove 203 and bend along the length direction of first section 201, and is through along the width direction of first section 201, etc., is set according to actual production demand.

[0044] Reference Figure 3 And Figure 4In some embodiments of the utility model, the thickness of the first section 201 is less than the thickness of the second section 202, and the first section 201 and the second section 202 jointly define at least one stepped groove 301. The tab 102 is a metal conductor that leads current out of the battery and is also the contact point when the battery is charging and discharging. They are responsible for connecting the electrical energy inside the battery with the external circuit, thereby realizing the charging and discharging function of the battery. However, when the size of the tab 102 is too large, it will occupy more space inside the battery cell, which means that under the same battery cell volume, the active material available for storing electrical energy will decrease, resulting in a corresponding decrease in the volumetric energy density of the battery cell. However, a tab 102 that is too small will adversely affect the current transmission efficiency, heating and short circuit risk, battery performance and life, and manufacturing and assembly difficulty of the battery cell. The thickness of the first section 201 is less than the thickness of the second section 202, which thins the first section 201 connecting the tab 102 and the pole piece 101, while the second section 202 extending relative to the pole piece 101 maintains the same thickness, thereby reducing the space occupied by the thinned portion, improving energy density while maintaining the size of the portion connected to the outside, so that it still has sufficient current transmission efficiency, etc., to ensure the quality of the battery cell. It should be noted that in some embodiments of the utility model, when the first section 201 is thinned as shown in Figure 3 and Figure 4 , a glue groove 203 can still be formed on the first section 201, thereby further improving space utilization and energy density.

[0045] It should be noted that referring to Figure 3 and Figure 4 , the stepped groove 301 can be formed on the surface of the first section 201 facing the blank area 106, or can be formed on the two side surfaces of the first section 201 in the thickness direction, further, it can also be formed on the surface of the first section 201 facing away from the blank area 106 according to the use requirement, to meet various requirements.

[0046] Referring to Figure 3In some embodiments of the present application, the thickness of the first section 201 is D1, the thickness of the second section 202 is D2, and 0.3 < (D1 / D2) < 0.8. The thickness of the first section 201 is less than that of the second section 202, and it also needs to be within a certain proportion range to meet the dual requirements of battery performance and energy density. When (D1 / D2) is less than or equal to 0.3, the thickness difference between the first section 201 and the second section 202 is too large, and the thickness difference of the tab 102 at different positions may cause uneven distribution of internal resistance in the battery. The thicker part of the tab 102 may have a higher resistance, while the thinner part may have a lower resistance. This unevenness may cause the overall internal resistance of the battery to increase, thereby reducing the power transmission efficiency of the battery. When (D1 / D2) is greater than or equal to 0.8, the thickness difference between the first section 201 and the second section 202 is not large, and the thinning effect is not obvious, and the improvement of energy density is also not significant.

[0047] It should be noted that, with reference to Figures 2 to 4 In some embodiments of the present application, along the thickness direction of the pole piece 101, the first section 201 is located between the topmost end and the lowest end of the pole piece 101. This design allows the first section 201 itself to not occupy too much space, so that the area where the blank area 106 is opened and the tab 102 is placed can have a lower thickness compared to directly coating the active material layer 105, thereby improving the space utilization.

[0048] With reference to Figures 5 to 8 In some embodiments of the present application, the width of the first section 201 is greater than the width of the second section 202. The width of the first section 201 is W1, and the width of the second section 202 is W2, and 0.2 < (W2 / W1) < 0.5. The first section 201 is used to bond the current collector 104, so the wider width of the first section 201 can increase the connection area with the current collector 104 and improve the structural stability of the connection. The second section 202 is used to connect with the outside, so the width is set to be smaller, and the thickness is set to be larger, which can meet the current carrying efficiency while reducing the occupied area of the second section 202 and improving the space utilization. The width of the first section 201 and the second section 202 is set within a certain proportion range, which can also meet the dual requirements of battery performance and energy density. When (W2 / W1) is less than or equal to 0.2, the width difference is too large, which is not convenient for processing and manufacturing, and may cause uneven distribution of internal current in the battery, affecting the output power and efficiency of the battery. When (W2 / W1) is greater than or equal to 0.5mm, the width difference is too small, and the improvement of energy density and the effect of structural optimization are not significant.

[0049] It should be noted that the width difference between the first section 201 and the second section 202 is preferably within the above-mentioned range, and the width of the first section 201 being greater than the width of the second section 202 itself has the effect of improving the structural stability and improving the energy density.

[0050] With reference to Figure 9 In some embodiments of the present application, the electrode assembly 100 further comprises a tab adhesive 901, a first insulating layer 902 and a second insulating layer 903. The tab adhesive 901 is connected to the second section 202, and the tab adhesive 901 is spaced apart from the first section 201. The first insulating layer 902 covers one side surface of the first section 201 facing away from the blank area 106. The second insulating layer 903 is coated on the outer surface of the second section 202, and the second insulating layer 903 is located between the tab adhesive 901 and the first section 201. The tab adhesive 901 is used to prevent short circuit between the tab 102 and the battery shell. During the battery packaging process, the tab adhesive 901 is sealed and bonded with the shell by heating, thereby ensuring electrical isolation inside the battery and preventing battery failure or safety accidents caused by short circuit. The first insulating layer 902 and the second insulating layer 903 also have the same effect of insulation protection, improving safety performance. It should be noted that in some embodiments of the present application, the first insulating layer 902 is an insulating adhesive, and the second insulating layer 903 is an insulating spray. Since the size of the second section 202 is small, the length and width of the part of the second section 202 between the tab adhesive 901 and the first section 201 are relatively small, so the insulating spray can comprehensively insulate this area. The size of the first section 201 is relatively large, and the use of insulating adhesive can better seal the first section 201 in the blank area 106, and the chemical properties of the insulating adhesive are more stable and will not react after contacting the active material layer 105.

[0051] According to the second aspect of the present application, the electrode assembly 100 comprises any one of the first aspect of the present application. The connection method in the prior art is to bond the tab 102 and the tab 101 by conductive adhesive 103, and the size of the connection in the thickness direction is the sum of the sizes of the tab 101, the conductive adhesive 103 and the connection of the tab 102 in the thickness direction. The electrode assembly 100 of the present application has an empty slot at the connection between the tab 102 and the tab 101, and the conductive adhesive 103 is arranged in the empty slot. Compared with the prior art, the conductive adhesive 103 can reduce the occupied space in the thickness direction, thereby improving the space utilization, and the battery cell using the electrode assembly 100 can effectively improve the energy density.

[0052] The utility model embodiment has been explained in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiment, still can make various changes in the knowledge range of the ordinary skill in the art who possesses under the premise of not departing from the utility model's tenet. Besides, the embodiment and the feature in the embodiment of the utility model can be combined mutually under the condition of not conflicting.

Claims

1. An electrode assembly, characterized by, The electrode assembly comprises: a pole piece comprising a current collector and an active material layer connected to the current collector, the current collector comprising a blank area exposed outside the active material layer; a tab comprising a first segment and a second segment connected to each other, the first segment being connected to the blank area, the first segment being provided with a glue groove; a conductive glue provided in the glue groove, the conductive glue connecting the first segment and the blank area.

2. The electrode assembly of claim 1, wherein, The first segment comprises a body portion and a protruding portion connected to each other, the protruding portion protruding towards the surface of the blank area relative to the body portion, an end of the protruding portion away from the body portion being in contact with the blank area, the glue groove being formed in the protruding portion.

3. The electrode assembly of claim 2, wherein, The thickness of the first segment is H1, the depth of the glue groove is H2, and 0.3*H1 4. The electrode assembly of claim 2, wherein, The total area of the first segment is S1, the total area of the glue groove is S2, and 0.7*S1 5. The electrode assembly of claim 1, wherein, The glue groove is provided with a plurality of glue grooves, the glue grooves are annular, and the plurality of glue grooves are concentrically and spacedly arranged.

6. The electrode assembly of claim 1, wherein, The glue groove is provided with a plurality of glue grooves, the glue grooves are rectangular, and the plurality of glue grooves are arranged in a rectangular array.

7. The electrode assembly of claim 1, wherein, The glue groove is provided with a plurality of glue grooves, the glue grooves are straight and strip-shaped grooves, the glue grooves pass through both ends of the first segment in the length direction, and the plurality of glue grooves are spacedly arranged in the width direction of the first segment.

8. The electrode assembly of claim 1, wherein, The thickness of the first segment is less than the thickness of the second segment, and the first segment and the second segment jointly define at least one stepped groove.

9. The electrode assembly of claim 8, wherein, The thickness of the first segment is D1, the thickness of the second segment is D2, and 0.3 10. The electrode assembly of claim 1, wherein, The width of the first segment is greater than the width of the second segment, the width of the first segment is W1, the width of the second segment is W2, and 0.2 11. The electrode assembly of claim 1, wherein, The electrode assembly further comprises: tab glue connected to the second segment, the tab glue being spacedly arranged with the first segment; a first insulating layer covering the side surface of the first segment away from the blank area; a second insulating layer coated on the outer surface of the second segment, and the second insulating layer being located between the tab glue and the first segment.

12. An electric cell characterized by The electrode assembly comprises: The electrode assembly of any one of claims 1-11.

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