Cover plate assembly, battery cell, and battery

Abstract

The present application relates to the technical field of batteries, and provides a cover plate assembly, a battery cell, and a battery. The cover plate assembly comprises a cover plate, a lower plastic member, a pole, and a tab insulating film; the lower plastic member is connected to the cover plate, and the lower plastic member is provided with a pole clearance hole; the pole is fixedly arranged on the cover plate and passes through the pole clearance hole; the pole is provided with a tab connecting slot; and the tab insulating film is arranged on the side of the lower plastic member facing away from the cover plate and is configured to insulate and isolate a tab of the battery cell from a casing of the battery cell.

Description

Cover plate assembly, battery cell and battery

[0001] The present application claims priority to Chinese Patent Application No. 202411246740.3 and 202422184636.8, filed on September 5, 2024, and Chinese Patent Application No. 202422761671.1, filed on November 12, 2024, with the Chinese Patent Office, the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to a cover plate assembly, a battery cell and a battery. BACKGROUND

[0003] At present, higher energy demands are put forward for power batteries in all-scene use environments. To meet this demand, the space utilization rate of the battery cell is mainly improved to increase the space for accommodating the pole piece in the battery cell, thereby increasing the energy density of the battery cell.

[0004] In the related art, the battery cell includes a shell, an electrode assembly arranged in the shell, and a cover plate assembly sealing an opening of the shell. The cover plate assembly includes a cover plate and a positive pole and a negative pole penetrating the cover plate. The electrode assembly includes a positive pole piece, a separator and a negative pole piece arranged in sequence. The pole piece is connected to the corresponding pole by a conductive connecting piece. SUMMARY

[0005] There is a height difference between the pole piece and the pole, to form a space for arranging the conductive connecting piece. As such, the internal space utilization rate of the battery cell is low, which adversely affects the energy density of the battery cell.

[0006] Embodiments of the present application provide a cover plate assembly, a battery cell and a battery, which can improve the internal space utilization rate of the battery cell.

[0007] In a first aspect, embodiments of the present application provide a cover plate assembly applied to a battery cell, which includes a cover plate, a lower plastic part, a pole and a tab insulation film. The lower plastic part is connected to the cover plate, and the lower plastic part is provided with a pole accommodation hole. The pole is fixed to the cover plate and penetrates the pole accommodation hole. An end of the pole close to the lower plastic part is provided with a tab connecting groove. The tab insulation film is arranged on a side of the lower plastic part away from the cover plate, and is configured to insulate and isolate the tab of the battery cell from the shell of the battery cell.

[0008] In a second aspect, embodiments of the present application provide an electric core, which comprises a shell, an electrode assembly, a tab, and a cover plate assembly; the shell has a receiving cavity; the electrode assembly is arranged in the receiving cavity; one end of the tab is connected with the electrode assembly; the cover plate is covered with the shell; the other end of the tab is located in a tab connecting groove and connected with a pole, and part of the tab insulating film is located between the tab and the shell.

[0009] In a third aspect, embodiments of the present application provide a battery, which comprises a box assembly and an electric core; the box assembly has a mounting cavity; the electric core is multiple; the multiple electric cores are connected in series and / or in parallel. Advantages

[0010] In embodiments of the present application, by arranging the tab connecting groove on the pole, not only the conductive connecting piece can be saved, and the space originally used for arranging the conductive connecting piece can be used for arranging the pole piece, but also the tab and the pole can share part of the height space, and the space originally used for arranging the tab can be used for arranging the pole piece. In this way, the internal space utilization rate of the electric core can be improved, and thus the energy density of the electric core can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1 is a structural schematic diagram of a cover plate assembly provided by embodiments of the present application;

[0012] FIG. 2 is a position schematic diagram of a tab insulating film provided by embodiments of the present application;

[0013] FIG. 3 is a structural schematic diagram of a pole provided by embodiments of the present application;

[0014] FIG. 4 is an enlarged view of A in FIG. 1;

[0015] FIG. 5 is a top view of a tab insulating film provided by embodiments of the present application;

[0016] FIG. 6 is a structural schematic diagram of a tab insulating film assembled to an electric core provided by embodiments of the present application;

[0017] FIG. 7 is a structural schematic diagram of a pole provided by embodiments of the present application;

[0018] FIG. 8 is a side view of a second surface of a pole provided by embodiments of the present application;

[0019] FIG. 9 is a sectional view along E-E in FIG. 8;

[0020] FIG. 10 is a schematic diagram of a pole cooperating with a tab provided by embodiments of the present application;

[0021] FIG. 11 is a structural schematic diagram of a body provided by embodiments of the present application;

[0022] FIG. 12 is a sectional view along B-B in FIG. 8;

[0023] Fig. 13 is an enlarged view of C in Fig. 12;

[0024] Fig. 14 is a side view of a second surface of yet another pole provided by an embodiment of the present application;

[0025] Fig. 15 is a side view of a second surface of still another pole provided by an embodiment of the present application;

[0026] Fig. 16 is a sectional view of yet another pole provided by an embodiment of the present application;

[0027] Fig. 17 is an exploded view of a cover assembly provided by an embodiment of the present application;

[0028] Fig. 18 is a sectional view of a cover assembly provided by an embodiment of the present application;

[0029] Fig. 19 is an enlarged view of D in Fig. 18;

[0030] Fig. 20 is a partial structural schematic view of a lower plastic part provided by an embodiment of the present application;

[0031] Fig. 21 is a structural schematic view of an electric core provided by an embodiment of the present application;

[0032] Fig. 22 is a partial structural schematic view of an electric core provided by an embodiment of the present application;

[0033] Fig. 23 is a structural schematic view of a battery provided by an embodiment of the present application.

[0034] Explanation of Reference Signs:

[0035] 1 - cover assembly;

[0036] 11 - cover; 111 - first surface;

[0037] 12 - lower plastic part; 121 - pole accommodation hole; 122 - first sink;

[0038] 13 - pole; 131 - tab connecting groove; 132 - flange;

[0039] 14 - tab insulating film; 141 - connecting portion; 142 - isolation portion; 143 - pole accommodation hole; 144 - exhaust accommodation hole; 145 - positioning hole; 146 - liquid injection accommodation hole;

[0040] 15 - hot melt connecting portion;

[0041] 16 - press ring; 17 - upper plastic part; 18 - sealing ring;

[0042] 2 - electric core; 21 - shell; 211 - accommodating cavity; 22 - electrode assembly; 23 - tab;

[0043] 3 - battery; 31 - case assembly; 32 - mounting cavity. Embodiments of the present application

[0044] Referring to FIG. 1, which is a structural schematic diagram of a cover plate assembly 1 provided by an embodiment of the present application, the embodiment of the present application provides a cover plate assembly 1 applied to a battery cell. The cover plate assembly 1 comprises a cover plate 11, a lower plastic part 12, a pole 13, and a tab insulation film 14. The lower plastic part 12 is connected with the cover plate 11. The lower plastic part 12 is provided with a pole accommodating hole 121. The pole 13 is fixedly arranged on the cover plate 11 and penetrates through the pole accommodating hole 121. The pole 13 is provided with a tab connecting groove 131 at an end close to the lower plastic part 12. The tab insulation film 14 is arranged on a side of the lower plastic part 12 away from the cover plate 11 and is configured to insulate and separate the tab of the battery cell from the shell 21 of the battery cell, as shown in FIG. 2, which is a position schematic diagram of the tab insulation film 14 provided by an embodiment of the present application.

[0045] Specifically, the cover plate 11 has a first surface 111. The lower plastic part 12 is connected with the first surface 111.

[0046] The tab insulation film 14 can be glued with the lower plastic part 12 or can be hot-melt connected with the tab insulation film 14. The tab insulation film 14 can also be connected with the cover plate 11.

[0047] In addition, the tab of the battery cell is at least partially located in the tab connecting groove 131 and is welded with the inner wall of the tab connecting groove 131. Optionally, the tab is welded with the groove bottom of the tab connecting groove 131.

[0048] In the embodiment, by arranging the tab connecting groove 131 on the pole 13, not only the conductive connecting piece can be omitted, but also the space originally used for arranging the conductive connecting piece can be used for arranging the pole, and a part of the height space shared with the pole 13 can be used for arranging the tab. In this way, the internal space utilization rate of the battery cell can be improved, and thus the energy density of the battery cell can be improved.

[0049] In addition, in some application environments, the battery cell needs to have more tabs, and correspondingly, the pole 13 with a larger size needs to be configured. When the tabs are more, the size of the tab stack will be larger. In order to reduce the space occupied by the tabs, the tabs need to be arranged by being bent. The radius of the tab bending increases as the size of the tab stack increases. When the radius of the tab bending is larger, the spacing between the outermost tab and the shell of the battery cell is smaller. In this way, the risk of short circuit caused by the contact between the tab and the shell is higher.

[0050] Based on this, in the embodiment, by arranging the tab insulation film 14, the insulation between the tab and the shell can be improved, and thus the risk of short circuit caused by the contact between the tab and the shell can be reduced, and the reliability of the battery cell can be improved.

[0051] In the embodiment, one part of the tab insulation film 14 is connected with the lower plastic part 12 or the cover plate 11, and functions to fix the tab insulation film 14. Another part of the tab insulation film 14 is arranged between the tab and the shell of the battery cell, and functions to insulate and separate the tab from the shell of the battery cell. In this way, the tab insulation film 14 has a simple structure, and thus material waste can be effectively avoided, and the material cost of the battery cell can be controlled.

[0052] Please refer to FIG. 3 and FIG. 4, FIG. 3 is a structural schematic diagram of the pole 13 provided by the embodiment of the application, and FIG. 4 is an enlarged view of A in FIG. 1. In an embodiment, the peripheral side wall of the pole 13 is provided with a flange 132. The flange 132 is arranged adjacent to the slot opening of the tab connecting slot 131. The flange 132 is overlapped with the side of the lower plastic part 12 which is away from the cover plate 11.

[0053] In the embodiment, by arranging the flange 132, on one hand, when the tab is inserted into the tab connecting slot 131 and welded with the pole 13, the flange 132 can support the part of the tab which is located outside the tab connecting slot 131, so as to reduce the deformation of the tab during welding, and thus the flatness of the contact part between the tab and the pole 13 can be effectively ensured, and the welding reliability between the tab and the pole 13 can be improved. On the other hand, the cover plate 11 can clamp and fix the lower plastic part 12 in combination with the flange 132, so as to improve the position stability of the lower plastic part 12, and thus the structural reliability of the cover plate assembly 1 can be improved.

[0054] Please refer to FIG. 4. In an embodiment, the side of the lower plastic part 12 which is away from the cover plate 11 is provided with a sunken first sunken part 122. The sunken first sunken part 122 is arranged around the peripheral edge of the pole accommodating hole 121, and the flange 132 is overlapped with the bottom wall of the sunken first sunken part 122. In this way, the matching structure between the pole 13 and the lower plastic part 12 can be increased, and thus the matching between the lower plastic part 12 and the pole 13 can be improved, so as to improve the structural reliability of the cover plate assembly 1.

[0055] In addition, by arranging the flange 132 in the sunken first sunken part 122, the part of the lower plastic part 12 where the sunken first sunken part 122 is arranged can be thickened. In this way, the thickness of other parts of the lower plastic part 12 can be controlled, so as to control the material usage and weight of the lower plastic part 12, and the thickness of the part of the lower plastic part 12 which matches with the pole 13 can be increased, so as to reduce the thermal influence on the lower plastic part 12 when the pole 13 is welded with the conductive member such as the tab or the terminal.

[0056] Please refer to FIG. 4, in an embodiment, the depth dimension of the first sink 122 is consistent with the thickness dimension of the flange 132. In this way, the part of the lower plastic part 12 adjacent to the first sink 122 is flush with the end face of the pole lug connecting groove 131 provided on the pole 13, so that when the pole lug is inserted into the pole lug connecting groove 131 and welded with the pole 13, the part of the pole lug outside the pole lug connecting groove 131 can be supported by the part of the lower plastic part 12 adjacent to the first sink 122, so as to reduce the deformation of the pole lug during welding, thereby effectively ensuring the flatness of the contact part between the pole lug and the pole 13. In this way, the welding reliability between the pole lug and the pole 13 can be improved.

[0057] Please refer to FIG. 1, in an embodiment, the distance X between the flange 132 and the edge of the lower plastic part 12 adjacent to the flange 132 satisfies: 3mm≤X.

[0058] It can be understood that the setting of the flange 132 reduces the distance between the pole 13 and the shell 21. Therefore, in order to ensure the insulation distance between the pole 13 and the shell 21, the distance X between the flange 132 and the edge of the lower plastic part 12 adjacent to the flange 132 is limited to avoid the risk of short circuit caused by too small distance X, thereby improving the circuit reliability of the battery cell.

[0059] Please refer to FIG. 1, in an embodiment, the pole lug insulation film 14 includes a connecting part 141 and an isolation part 142 connected with each other. The connecting part 141 is connected with the lower plastic part 12. The isolation part 142 is arranged in a direction away from the cover plate 11. The isolation part 142 is configured to insulate and isolate the pole lug of the battery cell from the shell 21 of the battery cell, as shown in FIG. 2. In this way, the pole lug insulation film has a simple structure, is easy to manufacture, and can control the material cost.

[0060] Please refer to FIG. 1, in an embodiment, the distance H1 between the end face of the isolation part 142 away from the cover plate 11 and the lower plastic part 12 satisfies: H1≥20mm. Or, the distance H1 between the end face of the isolation part 142 away from the cover plate 11 and the lower plastic part 12 and the height dimension H of the battery cell satisfy: 0.2H≤H1≤0.8H.

[0061] It can be understood that when H1≥20mm, the maximum value of H1 is basically required not to interfere with the bottom wall of the shell.

[0062] In the embodiment, the distance H1 between the end face of the isolation part 142 away from the cover plate 11 and the lower plastic part 12 is specifically the distance between the end face of the isolation part 142 away from the cover plate 11 and the part of the lower plastic part 12 connected with the pole lug insulation film 14.

[0063] In the embodiment, by limiting H1, the pole lug insulation film 14 has an isolation part 142 with sufficient length, so as to improve the insulation between the pole lug and the shell.

[0064] Please refer to FIG. 5, which is a top view of the tab insulation film 14 according to an embodiment of the present application. In an embodiment, the tab insulation film 14 is thermally fused with the lower plastic member 12. In this way, not only is there no need to use an adhesive such as glue, thereby avoiding aging or connection failure over time, but also the thermal fusion makes the lower plastic member 12 and the tab insulation film 14 melt into one, so that the connection is more solid.

[0065] In an embodiment, the length dimension L1 of the thermal fusion portion 141 between the tab insulation film 14 and the lower plastic member 12 in the direction away from the pole 13 satisfies: L1≥3mm. In this way, the reliability of the thermal fusion between the tab insulation film 14 and the lower plastic member 12 can be ensured.

[0066] It can be understood that the maximum value of the dimension L1 of the thermal fusion portion 141 is basically required not to interfere with other components of the cover plate assembly 1.

[0067] Please refer to FIG. 1. In an embodiment, the thickness dimension dd0 of the tab insulation film 14 satisfies: 0.05mm≤dd0≤0.5mm.

[0068] It can be understood that the thickness dimension dd0 of the tab insulation film 14 includes but is not limited to 0.05mm, 0.06mm, 0.8mm, 0.1mm, 0.15mm, 0.19mm, 0.2mm, 0.25mm, 0.28mm, 0.3mm, 0.36mm, 0.4mm, 0.45mm, 0.5mm.

[0069] In the present embodiment, by limiting the thickness dimension dd0 of the tab insulation film 14, on the one hand, the tab insulation film 14 can have appropriate strength to meet the insulation requirements; on the other hand, it can avoid unnecessary cost increase caused by excessive thickness.

[0070] Please refer to FIG. 6, which is a structural schematic diagram of the tab insulation film 14 assembled to the battery cell 2 according to an embodiment of the present application. In an embodiment, the battery cell is a square cell. The isolation portion 142 has two. Along the width direction of the square cell, the two isolation portions 142 are respectively located at the two ends of the connection portion 141. The isolation portion 142 is connected to the edge adjacent to the connection portion 141.

[0071] It can be understood that in the square cell, the tab is parallel to the large face of the square cell before being bent, i.e., the tab is perpendicular to the width direction of the square cell before being bent. When the tab is bent, the end of the tab is bent around the root of the tab towards the electrode assembly. In this way, the root of the tab protrudes along the width direction to the shell due to the bending, thereby causing the distance between the root of the tab and the shell in the width direction of the battery to be small.

[0072] Based on this, in the embodiment, the isolation portion 142 is arranged along the width direction of the square cell, so that when the cover plate assembly 1 is applied to the square cell, not only the insulation between the tab and the shell can be effectively ensured, but also the structure of the tab insulation film 14 is simple and easy to manufacture.

[0073] The connection portion 141 is provided with a pole 13 avoiding hole, an exhaust avoiding hole 144, a liquid injection avoiding hole 146, and a positioning hole 145. It can be understood that the pole 13 avoiding hole is used to avoid the pole 13, so as to facilitate the connection of the pole 13 and the tab. The exhaust avoiding hole 144 is used for the gas in the cell 2 to pass through, so as to facilitate the cell to exhaust and release pressure through the explosion-proof valve. The liquid injection avoiding hole 146 facilitates the electrolyte to pass through the positioning hole 145 to cooperate with the positioning column on the lower plastic part 12, so that the tab insulation film 14 can be quickly positioned on the lower plastic part 12, thereby improving the assembly efficiency.

[0074] Please refer to FIG. 4 and FIG. 7-FIG. 9, FIG. 7 is a structural schematic diagram of the pole 13 provided by the embodiment of the application, FIG. 8 is a side view of the second surface 111a of the pole 13 provided by the embodiment of the application, and FIG. 9 is a sectional view along E-E in FIG. 8. The cover plate 11 is provided with a mounting hole 211a, which is arranged opposite to the pole avoiding hole 121. The pole 13 includes a body 11a and a bottom plate 12a. The body 11a is arranged in the mounting hole 211a, and the tab connecting groove 131 is arranged at one end of the body 11a close to the lower plastic part 12. The bottom plate 12a is connected with the body 11a. The inner wall between the bottom plate 12a and the tab connecting groove 131 defines a tab mounting space 13a. The body 11a and / or the bottom plate 12a define a first opening 113. The first opening 113 is configured to communicate the tab mounting space 13a with the accommodating cavity of the cell.

[0075] Specifically, the body 11a defines the first opening 113, or the bottom plate 12a defines the first opening 113, or the body 11a and the bottom plate 12a jointly define the first opening 113.

[0076] Specifically, the end of the tab passes through the first opening 113 and is located in the tab mounting space 13a, and the tab is electrically connected with the bottom plate 12a or the body 11a, or the tab is electrically connected with the bottom plate 12a and the body 11a at the same time, so as to realize the current flow between the tab and the pole 13. As shown in FIG. 10, FIG. 10 is a schematic diagram of the cooperation between the pole 13 and the tab provided by the embodiment of the application.

[0077] Wherein, since the tab is a foil material, the thickness is small, therefore, the edges of the surfaces of the bottom plate 12a and the body 11a which are configured to contact with the tab are chamfered, and optionally, the edges of the surfaces of the bottom plate 12a and the body 11a which are configured to contact with the tab are rounded, so as to prevent the tab from being cut.

[0078] It can be understood that the part where the bottom plate 12a is connected with the body 11a is the flow-through part between the bottom plate 12a and the body 11a. Specifically, the bottom plate 12a is welded with the body 11a.

[0079] In the embodiment, by defining the tab mounting space 13a and the first opening 113 which is in communication with the accommodation cavity of the battery cell, the tab can pass through the first opening 113 and be located in the tab mounting space 13a. In this way, on the one hand, the tab shares the height space with the pole 13, so that the space originally occupied by the tab can be used to arrange the electrode assembly, thereby improving the energy density of the battery cell; on the other hand, the tab can be covered in the tab mounting space 13a, so that the part of the wall surface of the pole 13 which forms the tab mounting space 13a isolates the end of the tab from the electrode assembly, thereby effectively avoiding the tab from being inserted into the electrode assembly in reverse, so as to improve the reliability of the battery cell.

[0080] In addition, in the embodiment, by directly connecting the pole 13 with the tab, the conductive connecting piece connecting the tab and the pole 13 is omitted. In this way, not only the number of parts of the battery cell can be reduced to control the relevant cost and improve the assembly efficiency, but also the space used to arrange the conductive connecting piece can be used to arrange the electrode assembly, so as to improve the energy density of the battery cell.

[0081] Please refer to FIGS. 7-9, in some embodiments, the body 11a has a second surface 111a facing the accommodation cavity of the battery cell. The tab connecting groove 131 is arranged on the second surface 111a. The bottom plate 12a is arranged across the slot opening of the tab connecting groove 131. The bottom plate 12a covers part of the slot opening of the tab connecting groove 131 and defines the tab mounting space 13a with the inner wall of the tab connecting groove 131. Another part of the slot opening is the first opening 113.

[0082] In the embodiment, when the bottom plate 12a is arranged at the middle part of the slot opening of the tab connecting groove 131, the parts of the slot opening located on both sides of the bottom plate 12a define a first opening 113 respectively. In this way, part of the tab enters the tab mounting space 13a from a first opening 113, and another part of the tab enters the tab mounting space 13a from another first opening 113. In this way, the symmetry of the tab arrangement can be improved to improve the stress uniformity of the battery cell.

[0083] It can be understood that the periphery of the slot opening of the tab connecting groove 131 which is not covered by the bottom plate 12a and the edge of the bottom plate 12a adjacent thereto enclose the first opening 113. The interval between the bottom plate 12a and the groove bottom of the tab connecting groove 131 is the tab mounting space 13a, which is configured to cooperate with the tab of the battery cell.

[0084] It can be understood that the bottom plate 12a is arranged parallel to the slot opening of the tab connecting groove 131 to cover part of the slot opening of the tab connecting groove 131.

[0085] Specifically, the minimum distance between the bottom plate 12a and the groove bottom of the tab connecting groove 131 is D, which satisfies: 0.5mm≤D≤5mm. According to different models of batteries and the corresponding number of layers of positive and negative tabs, the distance between the bottom plate 12a and the groove bottom of the tab connecting groove 131 is adaptively designed.

[0086] In the embodiment, by setting the tab connecting groove 131 and the bottom plate 12a covering and defining the first opening 113 from the notch part of the tab connecting groove 131, the tab can pass through the gap between the bottom plate 12a and the groove wall of the tab connecting groove 131 and be located between the groove bottom of the tab connecting groove 131 and the bottom plate 12a. In this way, on the one hand, the pole 13 structure is simple and easy to form; on the other hand, the end of the tab can be isolated from the electrode assembly by the bottom plate 12a, so that the tab can be effectively prevented from being inserted into the electrode assembly in reverse, thereby improving the reliability of the battery cell.

[0087] Please refer to FIG. 11 and FIG. 12, FIG. 11 is a structural schematic diagram of the body 11a provided by the embodiment of the application, and FIG. 12 is a sectional view along B-B in FIG. 8. In an embodiment, the first step groove 114 is arranged on the two opposite groove walls of the tab connecting groove 131. The first step groove 114 is arranged adjacent to the notch of the tab connecting groove 131. The two ends of the bottom plate 12a are respectively overlapped with the two first step grooves 114.

[0088] In the embodiment, by arranging the first step groove 114 to overlap with the end of the bottom plate 12a, on the one hand, the bottom plate 12a can play a positioning role when the pole 13 is assembled, thereby improving the assembly efficiency of the pole 13 and facilitating the smooth welding of the bottom plate 12a and the body 11a; on the other hand, the body 11a and the bottom plate 12a can have more contact surfaces, thereby improving the reliability of the overcurrent between the body 11a and the bottom plate 12a.

[0089] Please refer to FIG. 9 or FIG. 11. In an embodiment, the surface of the bottom plate 12a away from the groove bottom of the tab connecting groove 131 is flush with the second surface 111a. In this way, the surface of the pole 13 towards the accommodating cavity of the battery cell can be flat, thereby reducing the arrangement difficulty of the electrode assembly and controlling the height of the pole 13 to increase the volume of the electrode assembly, thereby improving the energy density of the battery cell.

[0090] Please refer to FIG. 9 and FIG. 13, which is an enlarged view of C in FIG. 12. In an embodiment, along the axial direction of the pole 13, the thickness dimension d1 of the bottom plate 12a and the depth dimension d4 of the tab connecting groove satisfy: 30%d4≤d1≤70%d4.

[0091] It can be understood that the thickness dimension d1 of the bottom plate 12a includes but is not limited to 30% of d4, 32% of d4, 33% of d4, 34% of d4, 35% of d4, 38% of d4, 40% of d4, 43% of d4, 48% of d4, 50% of d4, 52% of d4, 54% of d4, 55% of d4, 56% of d4, 58% of d4, 60% of d4, 62% of d4, 64% of d4, 65% of d4, 67% of d4, 70% of d4.

[0092] It can be understood that the thickness dimension d1 of the bottom plate 12a also has a depth dimension for the first stepped groove 114.

[0093] In the embodiment, by limiting the thickness of the bottom plate 12a, on the one hand, the tab mounting space 13a has a sufficient height dimension, which is beneficial to the arrangement of the tab; on the other hand, the bottom plate 12a has a suitable strength to meet the isolation requirement between the tab and the electrode assembly, and the bottom plate 12a and the body 11a have a suitable area of the contact surface to meet the flow requirement between the bottom plate 12a and the body 11a.

[0094] Please refer to FIG. 14, which is a side view of the second surface 111a of another pole 13 according to an embodiment of the present application. In an embodiment, along the extension direction of the first stepped groove 114, the part of the bottom plate 12a that overlaps with the first stepped groove 114 is provided with an extension part 121a. The extension part 121a overlaps with the first stepped groove 114.

[0095] In the embodiment, by providing the extension part 121a, on the one hand, the area of the contact surface between the bottom plate 12a and the body 11a is increased, so as to improve the flow capacity between the bottom plate 12a and the body 11a; on the other hand, the area of the welding surface between the bottom plate 12a and the body 11a is increased, so as to improve the welding strength between the bottom plate 12a and the body 11a, thereby improving the structural stability of the pole 13.

[0096] Please refer to FIG. 15, which is a side view of the second surface 111a of another pole 13 according to an embodiment of the present application. In an embodiment, a reinforcing rib 122a is arranged in the included angle between the extension part 121a and the bottom plate 12a. The two sides of the reinforcing rib 122a are connected with the extension part 121a and the bottom plate 12a, respectively.

[0097] In the embodiment, the arrangement of the reinforcing rib 122a can enhance the strength of the connecting part between the extension part 121a and the body 11a, so as to avoid the damage of the extension part 121a caused by impact during assembly, thereby improving the assembly efficiency of the pole 13.

[0098] Please refer to FIG. 9, in an embodiment, the outer peripheral surface of the body 11a is provided with a flange 132 near the side of the second surface 111a.

[0099] It can be understood that the flange 132 is a structure formed by extending the outer circumferential surface of the body 11a in the radial direction of the pole 13.

[0100] In the embodiment, by arranging the flange 132, the position where the pole 13 is fitted with the top cover of the battery cell can be enlarged, so that the position stability of the pole 13 mounted to the battery cell can be improved.

[0101] Referring to FIG. 16, which is a sectional view of another pole 13 according to an embodiment of the application, in an embodiment, in the axial direction of the pole 13, the body 11a includes a first connecting piece 116 and a second connecting piece 117. One side of the first connecting piece 116 is connected with one side of the second connecting piece 117. The other side of the first connecting piece 116 is provided with a tab connecting groove 131. The bottom plate 12a is connected with the first connecting piece 116. The material of the first connecting piece 116 and the material of the bottom plate 12a are consistent with the material of the tab of the battery cell which is electrically connected with the tab, and the second connecting piece 117 is made of aluminum.

[0102] Specifically, when the negative tab is made of copper, the material of the bottom plate 12a and the first connecting piece 116 connected with the negative tab is copper.

[0103] The tab connecting groove 131 is arranged on the second connecting piece 117, and the second connecting piece 117 is connected with the first connecting piece 116 at a position close to the bottom of the tab connecting groove 131. In order to improve the connection strength between the first connecting piece 116 and the second connecting piece 117, the thickness of the position where the first connecting piece 116 is connected with the second connecting piece 117 in the axial direction of the pole 13 is d3, which satisfies d3≥0.5mm, so as to ensure the connection strength between the first connecting piece 116 and the second connecting piece 117 which are made of different materials.

[0104] In the embodiment, by the above arrangement, the material of the first connecting piece 116 and the material of the bottom plate 12a are consistent with the material of the tab connected therewith, so that the electrical conductivity between them can be improved, and the second connecting piece 117 is made of aluminum, so that the weight of the pole 13 can be reduced, thereby controlling the weight of the battery cell.

[0105] Referring to FIG. 1, FIG. 4 and FIG. 13, in an embodiment, the cover plate assembly 1 further includes a pressing ring 16. The body 11a has a third surface 119 configured to face away from the accommodating cavity of the battery cell. The periphery of the third surface 119 is provided with a second stepped groove 118. A third stepped groove 119a is arranged on the outer circumferential surface of the body 11a. In the axial direction of the pole 13, the second stepped groove 118 and the third stepped groove 119a are arranged in sequence away from the third surface 119. The position of the outer circumferential surface of the body 11a on the side of the third stepped groove 119a close to the third surface 119 is fitted with the pressing ring of the battery cell.

[0106] It can be understood that the body 11a needs to be sleeved with the compression ring 16 to fix the pole 13 on the cover plate 11 of the battery cell in the axial direction in combination with the flange 132. The compression ring 16 needs to be welded with the body 11a. The welding formed welding marks have a certain height size.

[0107] Based on this, in the embodiment, by setting the second stepped groove 118, the welding marks formed between the body 11a and the compression ring 16 are located in the second stepped groove 118, so that the flatness of the third surface 119 of the pole 13 and the compression ring 16 welded can be improved, and then the flatness when the pole 13 is combined with the connecting row can be improved. In this way, the welding reliability between the pole 13 and the connecting row can be improved, and the virtual welding can be effectively avoided.

[0108] Please refer to FIG. 13, in an embodiment, along the axial direction of the pole 13, the second stepped groove 118 has a depth size d2, and the pole has a height size H, which satisfies: 2%H≤d2≤10%H.

[0109] It can be understood that the depth size d2 of the second stepped groove 118 includes but is not limited to 2%H, 2.5%H, 3%H, 3.2%H, 3.8%H, 4%H, 4.2%H, 4.5%H, 5%H, 6%H, 6.2%H, 7%H, 7.4%H, 7.9%H, 8%H, 8.2%H, 8.5%H, 9%H, 9.2%H, 9.7%H, 10%H.

[0110] In the embodiment, by limiting the depth size of the second stepped groove 118, it can not only meet the requirement of accommodating the welding mark to improve the flatness of the third surface 119, but also avoid that the depth size is too large to affect the strength of the pole 13.

[0111] Please refer to FIG. 1, in an embodiment, the cover plate assembly 1 further comprises a compression ring 16, an upper plastic part 17 and a sealing ring 18. The compression ring 16 is sleeved on the pole 13 and is away from the slot opening of the tab connecting groove 131. The upper plastic part 17 is sleeved on the pole 13 and is located between the compression ring 16 and the cover plate 11. The sealing ring 18 is sleeved on the pole 13 and seals the fitting part between the pole 13 and the cover plate 11.

[0112] The compression ring 16 is welded with the pole 13 and cooperates with the flange 132 to fix the pole 13 on the cover plate 11. The sealing ring 18 is located between the flange 132 and the cover plate 11 and is in a compressed state, so as to form a sealing surface between the contact surface between the sealing ring 18 and the cover plate 11 and the contact surface between the sealing ring 18 and the flange 132.

[0113] Referring to FIGS. 17-19, FIG. 17 is an exploded view of the cover plate assembly according to an embodiment of the present application, FIG. 18 is a sectional view of the cover plate assembly according to an embodiment of the present application, and FIG. 19 is an enlarged view of D in FIG. 18. In an embodiment, the outer circumferential surface of the body 11a, which is away from the side of the compression ring 16, is provided with a flange 132 that is in abutting engagement with the cover plate 11. The side of the cover plate 11 that faces the accommodating cavity of the battery cell is provided with a second sunken platform 212a. The mounting hole 211a penetrates the bottom wall of the second sunken platform 212a. The inner and outer circumferential surfaces of the sealing ring 18 are in sealing engagement with the outer circumferential surface of the body 11a and the circumferential wall of the second sunken platform 212a, respectively. The two end surfaces of the sealing ring 18 are in sealing engagement with the bottom wall of the second sunken platform 212a and the flange 132, respectively.

[0114] In the embodiment, the outer circumferential surface of the flange 132 is in abutting engagement with the inner circumferential surface of the sealing ring 18 along the radial direction of the pole 13.

[0115] In the embodiment, the inner and outer circumferential surfaces and the two end surfaces of the sealing ring 18 all serve as sealing surfaces, which can improve the sealing between the cover plate 11 and the pole 13, thereby improving the reliability of the battery cell.

[0116] Referring to FIG. 19, in an embodiment, the outer radius of the sealing ring 18 is r1, and the inner radius is r2, and r1-r2≥3mm.

[0117] It can be understood that the difference between the outer radius r1 and the inner radius r2 of the sealing ring 18 includes but is not limited to 3mm, 3.2mm, 3.3m, 3.2mm, 3.4m, 3.5m, 3.6m, 3.7m, 3.8m, 3.9m, 4mm, 5mm, 6mm.

[0118] Alternatively, 3mm≤r1-r2≤10mm.

[0119] It can be understood that in the related art, the difference between the outer radius r1 and the inner radius r2 of the sealing ring 18 is 2mm. In the embodiment, after the sealing ring 18 is assembled, the bottom plate 12a and the body 11a need to be welded. The welding will affect the sealing performance of the sealing ring 18. Based on this, the radial dimension of the sealing ring 18 is lengthened, so that the area of the sealing surface in the radial direction is increased, thereby ensuring the sealing between the cover plate 11 and the pole 13 after the bottom plate 12a and the body 11a are welded.

[0120] Referring to FIGS. 18 and 19, in an embodiment, the body 11a has a third surface 119 configured to face away from the accommodating cavity of the battery cell. The compression ring 16 is welded to the body 11a, and the welding mark formed between the compression ring 16 and the body 11a does not protrude from the plane in which the third surface 119 is located.

[0121] It can be understood that the welding mark formed between the compression ring 16 and the body 11a has a certain height dimension. It can be understood that the welding mark formed between the compression ring 16 and the body 11a has a certain height dimension.

[0122] Based on this, in the embodiment, the welding mark formed by welding the compression ring 16 and the body 11a is not protruding from the third surface 119, so that the flatness of the third surface 119 where the pole 13 and the compression ring 16 are welded can be improved, and the flatness when the pole 13 and the connecting row are attached can be improved. In this way, the reliability of the welding between the pole 13 and the connecting row can be improved, and the risk of false welding can be effectively avoided.

[0123] Specifically, the periphery of the third surface 119 is provided with a second stepped groove 118, so that the welding mark formed by welding the body 11a and the compression ring 16 is located in the second stepped groove 118.

[0124] Please refer to FIG. 20, which is a partial structure diagram of the lower plastic part 12 provided by the embodiment of the application. In an embodiment, the side of the lower plastic part away from the cover plate 11 is provided with a receiving groove 241. The receiving groove 241 is configured to accommodate part of the tab of the battery cell. The receiving groove 241 is adjacent to the pole accommodation hole 121, and the opening of the receiving groove 241 and the first opening 113 are oriented in the same direction.

[0125] It can be understood that the lower plastic part is also provided with a pole accommodation hole 121 for the tab to pass through. The tab is located between the bottom plate 12a and the bottom of the tab connecting groove 131 after passing through the pole accommodation hole 121 and the first opening 113 in sequence.

[0126] The receiving groove 241 is adjacent to the first opening 113 and located on the side of the first opening 113 away from the bottom plate 12a. The first opening 113 has two, and the two first openings 113 are respectively located on both sides of the bottom plate 12a. Correspondingly, the receiving groove 241 has two, and the two receiving grooves 241 are respectively located on the side of the two first openings 113 away from the bottom plate 12a.

[0127] In the embodiment, by providing the receiving groove 241, the lower plastic part 12 not only plays a role of insulating and protecting the electrode assembly and the cover plate 11, but also can accommodate the bent tab through the receiving groove 241, so that the tab can be effectively prevented from being inserted into the electrode assembly in reverse.

[0128] In an embodiment, the height of the lower plastic part 12 is H0, which satisfies: H0≥2mm.

[0129] It can be understood that in the prior art, in order to make the lower plastic part 12 have enough space to accommodate the tab and the conductive connecting piece, the minimum height of the lower plastic part 12 is 5 mm. In the embodiment, the height space of the tab and the pole 13 is shared, and the tab is blocked by the bottom plate 12a to avoid the tab from being inserted into the electrode assembly reversely. Therefore, in the embodiment, the height of the lower plastic part 12 can be reduced to 2 mm. Therefore, the size of the electrode assembly can be increased to improve the energy density of the battery cell, and the material cost of the lower plastic part 12 can be reduced to control the cost of the battery cell.

[0130] Referring to FIG. 21 and FIG. 22, FIG. 21 is a structural schematic diagram of a battery cell 2 provided by an embodiment of the present application, and FIG. 22 is a partial structural schematic diagram of a battery cell provided by an embodiment of the present application. Accordingly, an embodiment of the present application provides a battery cell 2. The battery cell 2 includes a shell 21, an electrode assembly 22, a tab 23, and a cover plate assembly 1 provided by some embodiments of the present application. The shell 21 has a receiving cavity 211. The electrode assembly 22 is arranged in the receiving cavity 211. One end of the tab 23 is connected with the electrode assembly 22. The cover plate 11 is covered with the shell 21. The other end of the tab 23 is located in the tab connecting groove 131 and connected with the pole 13. The tab insulating film 14 is located between the tab 23 and the shell 21.

[0131] Specifically, the isolation part 142 is located between the tab 23 and the shell 21.

[0132] Specifically, the tab 23 is connected with the bottom plate 12a, or the tab 23 is connected with the body 11a, or the tab 23 is connected with both the bottom plate 12a and the body 11a.

[0133] It can be understood that the electrode assembly 22 includes a positive electrode sheet, a separator, and a negative electrode sheet arranged in sequence. In the wound electrode assembly 22, the positive electrode sheet, the separator, and the negative electrode sheet are arranged in sequence and wound.

[0134] Among them, the pole 13 includes a positive pole and a negative pole, the tab 23 includes a positive tab and a negative tab, the positive tab is connected with the positive electrode sheet and the positive pole, and the negative tab is connected with the negative electrode sheet and the negative pole.

[0135] Optionally, the battery cell 2 is a square battery cell. The electrode assembly 22 has two, and the two electrode assemblies 22 are arranged along the width direction of the square battery cell. The positive tab of one electrode assembly 22 is connected with one side of the inner wall of the tab connecting groove 131 of the positive pole, and the positive tab of the other electrode assembly 22 is connected with the other side of the inner wall of the tab connecting groove 131 of the positive pole. The negative tab of one electrode assembly 22 is connected with one side of the inner wall of the tab connecting groove 131 of the negative pole, and the negative tab of the other electrode assembly 22 is connected with the other side of the inner wall of the tab connecting groove 131 of the negative pole.

[0136] In the embodiment, by adopting the cover plate assembly 1 disclosed in some embodiments of the present application, not only the conductive connecting piece can be saved, and the space originally used for arranging the conductive connecting piece can be used for arranging the pole piece, but also the tab 23 and the pole 13 can share a part of height space, and the space originally used for arranging the tab 23 can be used for arranging the pole piece. In this way, the internal space utilization rate of the battery cell 2 can be improved, and thus the energy density of the battery cell 2 can be improved.

[0137] Please refer to FIG. 23, which is a structural schematic diagram of a battery 3 provided by an embodiment of the present application. Accordingly, the embodiments of the present application also provide a battery 3, which comprises a box assembly 31 and the battery cell 2 provided by some embodiments of the present application. The box assembly 31 has a mounting cavity 32. The battery cell 2 is multiple, and the multiple battery cells 2 are connected in series and / or in parallel.

[0138] In the embodiment, by adopting the battery cell 2 disclosed in some embodiments of the present application, not only the conductive connecting piece can be saved, and the space originally used for arranging the conductive connecting piece can be used for arranging the pole piece, but also the tab 23 and the pole 13 can share a part of height space, and the space originally used for arranging the tab 23 can be used for arranging the pole piece. In this way, the internal space utilization rate of the battery cell 2 can be improved, and thus the energy density of the battery 3 can be improved.

Claims

A cover plate assembly (1) applied to a battery cell (2) comprises: a cover plate (11); a lower plastic part (12) connected with the cover plate (11), the lower plastic part (12) is provided with a pole post accommodation hole (121); a pole post (13) fixedly arranged on the cover plate (11) and penetrating through the pole post accommodation hole (121), one end of the pole post (13) close to the lower plastic part (12) is provided with a tab connecting groove (131); a tab insulating film (14) arranged on the side of the lower plastic part (12) away from the cover plate (11) and configured to insulate and isolate the tab (23) of the battery cell (2) from the shell (21) of the battery cell (2). The cover plate assembly (1) according to claim 1, wherein The peripheral side wall of the pole post (13) is provided with a flange (132), the flange (132) is arranged adjacent to the notch of the tab connecting groove (131), and the flange (132) is overlapped with the side of the lower plastic part (12) away from the cover plate (11). The cover plate assembly (1) according to claim 2, wherein The side of the lower plastic part (12) away from the cover plate (11) is provided with a sunken platform first sunken platform (122), the sunken platform first sunken platform (122) is arranged around the peripheral edge of the pole post accommodation hole (121), and the flange (132) is overlapped with the bottom wall of the sunken platform first sunken platform (122). The cover plate assembly (1) according to claim 3, wherein The depth dimension of the sunken platform first sunken platform (122) is consistent with the thickness dimension of the flange (132). The cover plate assembly (1) according to any one of claims 2-4, wherein The distance between the flange (132) and the outer edge adjacent to the lower plastic part (12) is X, and 3mm≤X. The cover plate assembly (1) according to any one of claims 1-5, wherein The tab insulating film (14) comprises a connecting part (141) and an isolating part (142) connected with each other, the connecting part (141) is connected with the lower plastic part (12), the isolating part (142) is arranged in the direction away from the cover plate (11), and the isolating part (142) is configured to insulate and isolate the tab (23) of the battery cell (2) from the shell (21) of the battery cell (2). Cover assembly (1) according to claim 6, wherein The distance between the end face of the isolating part (142) away from the cover plate (11) and the lower plastic part (12) is H1, and H1≥20mm; Or, the distance between the end face of the isolating part (142) away from the cover plate (11) and the lower plastic part (12) is H1, and the height dimension of the battery cell (2) is H, and 0.2H≤H1≤0.8H. Cover assembly (1) according to claim 6 or 7, wherein The tab insulating film (14) is hot melt connected with the lower plastic part (12). Cover assembly (1) according to claim 8, wherein In the direction away from the pole post (13), the hot melt connection part (141) between the tab insulating film (14) and the lower plastic part (12) has a length dimension L1, and L1≥3mm. The cover plate assembly (1) according to any one of claims 7-9, wherein The thickness dimension of the tab insulating film (14) is dd0, and 0.05mm≤dd0≤0.5mm. Cover assembly (1) according to any of claims 7-10, wherein The electric core (2) is a square shell electric core (2), the isolation part (142) has two, along the width direction of the square shell electric core (2), two isolation parts (142) are located at two ends of the connecting part (141) respectively, and the isolation part (142) is connected with the edge adjacent to the connecting part (141). Cover assembly (1) according to any one of claims 1-11, wherein The cover plate (11) is provided with a mounting hole (211a) which is arranged opposite to the pole post accommodation hole (121); the pole post (13) comprises: A body (11a) is arranged in the mounting hole (211a), and the tab connecting groove (131) is arranged at one end of the body (11a) close to the lower plastic part (12); A bottom plate (12a) is connected with the body (11a), and an inner wall between the bottom plate (12a) and the tab connecting groove (131) defines a tab mounting space (13a); the body (11a) and / or the bottom plate (12a) define a first opening (113), and the first opening (113) is configured to communicate the tab mounting space (13a) with the accommodating cavity (211) of the electric core. Cover assembly (1) according to claim 12, wherein The body (11a) has a second surface (111a) configured to face the accommodating cavity (211) of the electric core, and the tab connecting groove (131) is arranged on the second surface (111a); The bottom plate (12a) is arranged across the notch of the tab connecting groove (131) and covers part of the notch, and the bottom plate (12a) and the inner wall of the tab connecting groove (131) define the tab mounting space (13a); another part of the notch is the first opening (113). The cover plate assembly (1) according to claim 13, wherein First step grooves (114) are arranged on two opposite groove walls of the tab connecting groove (131), and the first step grooves (114) are arranged adjacent to the notch; and two ends of the bottom plate (12a) are respectively overlapped with the two first step grooves (114). The cover plate assembly (1) according to claim 14, wherein The surface of the bottom plate (12a) away from the groove bottom of the tab connecting groove (131) is flush with the second surface (111a). The cover plate assembly (1) according to claim 15, wherein In the axial direction of the pole post (13), the bottom plate (12a) has a thickness dimension d1, and the depth dimension of the tab connecting groove (131) is d4, and the following is satisfied: 30 %d4≤d1≤70 %d4. The cover plate assembly (1) according to any one of claims 14-16, wherein In the extension direction of the first step groove (114), the part of the bottom plate (12a) overlapped with the first step groove (114) is provided with an extension part (121a), and the extension part (121a) is overlapped with the first step groove (114). Cover assembly (1) according to claim 17, wherein A reinforcing rib (122a) is arranged in the included angle between the extension part (121a) and the bottom plate (12a), and two sides of the reinforcing rib (122a) are respectively connected with the extension part (121a) and the bottom plate (12a). The cover plate assembly (1) according to any one of claims 12-18, further comprising a compression ring (16); the body (11a) has a third surface (119) configured as a receiving cavity (211) facing away from the battery cell, and a periphery of the third surface (119) is provided with a second stepped groove (118); A third stepped groove (119a) is provided on an outer peripheral surface of the body (11a) in an axial direction of the pole post (13), and the second stepped groove (118) and the third stepped groove (119a) are sequentially provided away from the third surface (119); and a portion of the outer peripheral surface of the body (11a) located on a side of the third stepped groove (119a) close to the third surface (119) is matched with the compression ring (16). Cover assembly (1) according to claim 19, wherein In the axial direction of the pole post (13), the second stepped groove (118) has a depth dimension d2, and the pole post (13) has a height dimension H, and the following condition is met: 2<H≤d2≤10%H. Cover assembly (1) according to any of claims 12-20, wherein The cover plate assembly (1) further comprises a compression ring (16), an upper plastic part (17) and a sealing ring (18), the compression ring (16) is sleeved on the pole post (13) and is arranged away from the slot opening of the tab connecting groove (131), the upper plastic part (17) is sleeved on the pole post (13) and is located between the compression ring (16) and the cover plate (11); and the sealing ring (18) is sleeved on the pole post (13) and seals a matching portion between the pole post (13) and the cover plate (11). The cover plate assembly (1) according to claim 21, wherein An outer peripheral surface of the body (11a) on a side facing away from the compression ring (16) is provided with a flange (132) matched with the cover plate (11) in abutment, a side of the cover plate (11) facing away from the compression ring (16) is provided with a second sunken platform (212a), and the mounting hole (211a) penetrates a bottom wall of the second sunken platform (212a); inner and outer peripheral surfaces of the sealing ring (18) are respectively matched with an outer peripheral surface of the body (11a) and a peripheral wall of the second sunken platform (212a) in sealing, and two end surfaces of the sealing ring (18) are respectively matched with the bottom wall of the second sunken platform (212a) and the flange (132) in sealing. Cover assembly (1) according to claim 22, wherein An outer radius of the sealing ring (18) is r1, and an inner radius of the sealing ring (18) is r2, and the following condition is met: r1-r2≥3mm. The cover plate assembly (1) according to any one of claims 21-23, wherein The body (11a) has a third surface (119) configured as a receiving cavity (211) facing away from the battery cell, and the compression ring (16) is welded with the body (11a), and a welding mark formed by welding between the compression ring (16) and the body (11a) does not protrude from a plane in which the third surface (119) is located. The cover plate assembly (1) according to any one of claims 1-24, wherein A side of the lower plastic part facing away from the cover plate (11) is provided with a receiving groove (241) configured to accommodate a portion of the tab (23) of the battery cell, and the receiving groove (241) is arranged adjacent to the pole post accommodation hole (121). A battery cell (2) comprises: A shell (21) having a receiving cavity (211); An electrode assembly (22) arranged in the receiving cavity (211); a tab (23) connected to the electrode assembly (22) at one end; and the cover plate assembly (1) according to any one of claims 1-25, wherein the cover plate (11) covers the shell (21); wherein the other end of the tab (23) is located in the tab connecting groove (131) and connected to the inner wall of the post (13), and part of the tab insulating film (14) is located between the tab (23) and the shell (21). A battery (3) comprising: a box assembly (31) having a mounting cavity (32); and the battery cell (2) according to claim 26, wherein there are a plurality of battery cells (2), and the plurality of battery cells (2) are connected in series and / or in parallel.

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