Lid arrangement for a prismatic battery cell

Abstract

Lid arrangement (1) for a battery cell, wherein the lid arrangement (1) is configured to seal an interior (3) of the battery cell in a fluid-tight manner, and comprises a base plate (4) configured to seal an opening (3a) of the interior (3); wherein the base plate (4) has an injection hole (12) which allows the injection of an electrolyte material into the interior (3), wherein the lid arrangement (1) further comprises a closure device (8) for fluid-tight sealing of the injection hole (12), wherein the closure device (8) comprises a closure element (10) which is coupled to the base plate (4) at the injection hole (12); wherein the locking element (10) has a substantially flattened configuration and has at least two raised sections (18) arranged on opposite sides of the locking element (10) itself.

Description

TECHNICAL AREA

[0001] The invention relates to a lid arrangement for a prismatic battery cell, in particular a lid arrangement for closing and sealing a fluid-tight interior of a prismatic battery cell containing electrodes and electrolyte material. STATE OF THE ART

[0002] Battery cells are known to be used as electrical energy storage devices.

[0003] In particular, so-called primary batteries are known, which cannot be easily recharged and are therefore designed for single use and subsequent disposal.

[0004] There are also so-called secondary batteries that can be recharged several times after each usage cycle.

[0005] Secondary batteries are known to be used for various small-format portable electronic devices, such as mobile phones, watches, smartwatches, smartbands, etc.

[0006] Furthermore, batteries are known that comprise a plurality of cells connected in series or parallel and are generally used in the automotive industry.

[0007] The invention relates to a battery cell for use in a battery of an electric or hybrid vehicle, without, however, limiting the general applicability of the invention.

[0008] Secondary battery cells can be manufactured in various types and shapes, for example as cylindrical or prismatic cells.

[0009] The present invention relates to prismatic battery cells, without, however, limiting the general applicability of the invention.

[0010] A prismatic battery cell typically comprises a hollow prismatic casing (or shell), for example in the shape of a parallelepiped and usually made of a metallic material, and two electrodes (cathode and anode) housed within the casing, which defines an interior space of the cell.

[0011] The interior also contains a separator material that is electrically positioned between the two electrodes.

[0012] Inside the interior, the electrodes and the separator are immersed in an electrolyte solution, which is usually liquid or gel-like.

[0013] The battery cell further includes at least one lid assembly that is coupled to the housing to seal the interior in a fluid-tight manner.

[0014] More precisely, the housing typically has at least one (rectangular) opening, usually located on the top, through which the electrodes and separator are inserted into the interior. The lid assembly is coupled to the housing to close this opening, thus sealing the interior.

[0015] The lid arrangement typically includes: - a base plate, typically made of metal, which is positioned to correspond to and engage with the opening of the housing to seal the interior; - a current collector for each electrode, which is electrically connected to the respective electrode and configured to absorb the electrical energy coming from the electrode and deliver it from the interior to the external environment; and - a connection element for each electrode, which is electrically connected to the respective current collector in order to receive electrical energy from it, and is configured to accept a connector of a device which is to be powered by the battery cell.

[0016] In each electrode, the connecting element and the current collector are usually coupled (electrically and mechanically) to each other via a pin or rivet that engages in a respective through-hole formed in the base plate.

[0017] In other words, the connection element is located on a first outer side of the base plate, while the current collector is located on a second inner side of the base plate, opposite the first side.

[0018] In light of the foregoing, the connection element, the pin, and the current collector together define a connection arrangement of the cover assembly. The connection arrangement has a longitudinal axis, and the pin is generally coaxial with this axis.

[0019] The cover arrangement can include two or more such connection arrangements.

[0020] A typical cover arrangement further includes a first insulating element for each connection arrangement, which is arranged between the respective connection element and the base plate to electrically isolate the connection element from the base plate.

[0021] A typical cover arrangement further includes a second insulating element for each connection arrangement, which is positioned between the respective current collector and the base plate to electrically isolate the current collector from the base plate.

[0022] During the assembly of the battery cell, the various components mentioned above are stacked axially with respect to the longitudinal axis of the connection arrangement and pressed together.

[0023] According to known processes for manufacturing such battery cells, the interior is filled with electrolyte material after the lid assembly is attached to the housing, and in particular after the base plate is welded to the opening of the housing.

[0024] For this purpose, the lid assembly is provided with a relatively small through-hole, commonly referred to as the "injection hole" for the electrolyte.

[0025] The injection hole is formed through the base plate and serves to inject the electrolyte material into the interior after the lid assembly has been coupled to and attached to the housing.

[0026] The injection hole thus defines an opening in the base plate.

[0027] After the electrolyte is injected, the injection hole must be sealed. For this purpose, the lid assembly includes a sealing device, which typically comprises two components: - a rubber sealing stick; and - a cover or closure element, typically defined by a shaped aluminum plate.

[0028] Typically, the injection hole includes a through hole formed through the base plate and a recess formed in the base plate surrounding the through hole.

[0029] The sealing pin is usually fitted by means of a press fit so that it engages in the through hole, and then the cover is inserted into a designated seat defined by the recess and welded to it, usually at a circumferential edge that laterally limits the recess.

[0030] The cover is therefore located above the sealing pin.

[0031] It is known that, due to an elastic retraction of the sealing pin during the assembly process of the cover assembly, the sealing pin may protrude slightly from the through-hole in the axial direction.

[0032] For this purpose, it is known to shape the cover in such a way that a raised central section is created on the sealing pin. In this way, a space is created between the cover and the base plate at the through-hole, into which the section of the sealing pin that may protrude from the through-hole during use can freely engage.

[0033] As a result, the cover (or the sealing element of the injection hole) protrudes from the depression in order to enlarge the aforementioned space as much as possible.

[0034] Due to potential interference with other cells or other battery components, there is a need to reduce dimensions and limit protrusions from the base plate.

[0035] At the same time, it is important to avoid complicating the manufacturing and assembly process of the lid assembly by minimizing additional work steps and time losses. SUBJECT AND SUMMARY OF THE INVENTION

[0036] The invention is based on the objective of providing a lid arrangement for a prismatic battery cell that is extremely reliable and cost-effective and overcomes at least some of the aforementioned disadvantages of known lid arrangements.

[0037] According to the invention, this problem is solved by a lid arrangement according to claim 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The invention is best understood by reference to the following description of a preferred, non-limiting embodiment, which serves only as an example, with reference to the accompanying drawings, wherein: - Fig. 1 a schematic perspective exploded view of a battery cell with a lid arrangement according to the invention, wherein parts have been removed for better clarity; - Fig. 2a is an enlarged top view of a closure element for an electrolyte material injection hole of the lid assembly, with parts removed for clarity; - Fig. 2b a perspective view of the locking element of Fig. 2a is; and - Fig. Figure 3 is a sectional view of an area of ​​the injection hole, showing the injection hole and a closure device for the injection hole, with parts removed for clarity. DETAILED DESCRIPTION

[0039] With reference to the attached figures, reference numeral 1 designates a cover arrangement for a battery cell.

[0040] In particular, the battery cell is of the prismatic type and has a hollow prismatic housing 2 which defines an interior space 3 and has an opening 3a for access to the interior space 3.

[0041] According to the embodiment shown here, the housing 2 has the shape of a parallelepiped. Alternatively, the housing 2 could have any prismatic shape, for example a cubic prismatic shape, a prismatic shape with a triangular base, etc.

[0042] In one embodiment, the housing 2 can be cylindrical. In this case, the cover arrangement 1 has a circular configuration.

[0043] The invention relates to a prismatic battery cell, without, however, limiting the general applicability of the invention.

[0044] In particular, the present invention relates to a battery cell for use in the automotive industry, for example in a battery module of an electric or hybrid vehicle, without, however, limiting the general applicability of the invention.

[0045] The battery cell further comprises electrodes (cathode and anode, not shown) which are housed together with a separator material (not shown) and an electrolyte material (not shown) in the interior 3.

[0046] The electrolyte material can be liquid or gel-like.

[0047] The electrodes and the separator material are introduced into the interior 3 through opening 3a.

[0048] As a result, the lid arrangement 1 is configured so that it can be coupled to the housing 2 at the opening 3a to seal the interior 3 in a fluid-tight manner, as is required during normal use of the battery cell.

[0049] Therefore, the battery cell comprises the housing 2 with the electrodes, the separator and the electrolyte solution, as well as the lid assembly 1.

[0050] The battery cell is preferably part of a battery module containing a plurality of battery cells that are electrically connected in parallel.

[0051] The housing 2 may have a further opening 3a opposite the previously mentioned opening 3a, as shown in Fig. Figure 1 shows a further cover assembly 1. Another cover assembly 1 must be coupled to the housing 2 to seal the further opening 3a in a fluid-tight manner. For the sake of brevity, the following refers to a single cover assembly 1.

[0052] As in Fig. As shown in Figure 1, the cover arrangement 1 comprises a base plate 4 made of a metal material, such as aluminum or stainless steel, which is configured to be coupled to the housing 2 at the opening 3a in order to close the opening 3a of the interior 3, that is to say, designed to conform to the shape of the opening 3a and engage in it to close the interior 3.

[0053] The lid arrangement 1 further comprises at least one connection arrangement 50, and in particular two connection arrangements 50, which are configured so that they can be electrically connected on their inner side 5 to a respective electrode inside the interior 3 in order to receive electrical energy from it, and are configured so that they can be electrically coupled on their outer side 6 to a connector of a device (not shown) which is to be supplied with energy by the battery cell.

[0054] In particular, each connection arrangement 50 has a longitudinal axis X and comprises: - a current collector 5 that defines the aforementioned inside of the connection arrangement 50 and is configured so that it can be electrically connected to the respective electrode; - a connection element 6 that defines the aforementioned outer side of the connection arrangement 50 and is configured so that it can be electrically coupled to the aforementioned connector; and - a pin 5b which is arranged axially between the current collector 5 and the connection element 6 and electrically connects them.

[0055] In particular, the pin 5b is welded to the connecting element 6 on its axial side and to the current collector 5 on its opposite axial side.

[0056] Preferably, the pin 5b is arranged in a substantially cylindrical form and coaxially to the axis X.

[0057] The connection arrangement 50 extends along the axial direction from the interior 3 to an external environment that lies outside the interior 3.

[0058] Specifically, the connecting element 6 is located on an outer side of the base plate 4 (namely the side facing the outside environment), so that it can be connected to the connector, and the collector 5 is located on an inner side of the base plate 4 (namely the side facing the interior 3), so that it can be connected to the respective electrode.

[0059] The base plate 4 expediently has a through hole 4a into which the pin 5b engages.

[0060] The pin 5b engages with the terminal element 6 to establish the electrical connection between the collector 5 and the terminal element 6.

[0061] Based on the above, the current collector 5 and the connection element 6 are located on opposite sides of the base plate 4 with respect to the axial direction.

[0062] The cover arrangement 1 can comprise two or more connection arrangements 50. In Fig. Figure 1 shows two connection arrangements 50. For the sake of brevity, only one connection arrangement 50 will be considered in the following.

[0063] The cover assembly 1 preferably comprises an insulating element 7, which is arranged axially between the connecting element 6 and the base plate 4 in order to electrically isolate the connecting element 6 from the base plate 4. The insulating element 7 is expediently made of an electrically insulating material, such as PPS (polyphenylene sulfide) or PP (polypropylene).

[0064] The cover arrangement 1 can include sealing elements, for example O-rings, which are arranged between the base plate 4 and the connection arrangement 50 and are configured to seal the interior 3 fluid-tight against the external environment.

[0065] Preferably, the lid arrangement 1 further comprises a stop frame 11 made of an electrically insulating material (such as rigid plastic), which is known per se and is therefore not described in detail.

[0066] The base plate 4 has an inner surface 14 configured to face the interior 3 when the base plate 4 is coupled to the housing 2 (that is, when the cover assembly 1 is attached to the housing 2), and an outer surface 15 opposite the inner surface 14 configured to face outwards with respect to the interior 3.

[0067] The lid arrangement 1 further comprises: - an injection hole 12 to allow the injection (or introduction) of the electrolyte material into the interior; and - a closure device 8 for fluid-tight sealing of the injection hole.

[0068] In practice, the injection hole 12 defines an opening through which the electrolyte material is introduced into the interior 3 in a known manner, which is not described in detail, as soon as the lid arrangement 1 is coupled to the housing 2.

[0069] The locking device 8 comprises a locking element 10, which is preferably defined by a cover or plate, preferably made of a metal material, for example aluminium.

[0070] The closure element 10 is coupled to the base plate at the injection hole 12.

[0071] Specifically, the closure element 10 covers the injection hole 12, as explained in more detail below.

[0072] The locking element 10 is preferably defined by a disc-shaped body with a substantially circular profile.

[0073] In other words, according to this preferred, non-restrictive embodiment, the locking element 10 is defined by a disc-shaped plate.

[0074] In the following, the locking element 10 can be referred to as "cover 10".

[0075] The closure device 8 preferably further comprises a sealing pin 13 which engages fluid-tight in the injection hole 12.

[0076] The sealing pin 13 is known and will not be described in detail.

[0077] The injection hole 12 has a central axis A and, extending radially from the inside to the outside, comprises at least one through hole 16 and a first recess 17 surrounding the through hole 16.

[0078] The through-hole 16 defines the opening for the fluid connection with the interior 3, through which the electrolyte material is introduced.

[0079] The sealing pin 13 engages fluid-tight in the through-hole 16 to prevent the electrolyte material from leaking out or foreign substances from entering the interior 3.

[0080] The cover 10 overlaps the through hole 16 and the first recess 17 and is coupled to the base plate so that it completely covers the first recess 17 (and thus also the through hole 16).

[0081] According to one aspect of the invention, the cover 10 has a substantially flattened configuration and has at least two raised sections 18 arranged on opposite sides of the cover 10.

[0082] In particular, the cover 10 comprises a main section (or middle section) 10a and a perimeter section 10b, and the raised sections 18 project orthogonally from the main section 10a, thereby defining elevations 18 projecting from the main section 10a.

[0083] In particular, the cover 10 has a first surface 19a facing the injection hole 12, and especially the first depression 17, and a second surface 19b opposite the first surface 19a. The cover 10 comprises a first protrusion 18 located on the first surface 19a and a second protrusion 18 located on the second surface 19b.

[0084] In this way, the cover 10 includes at least one elevation 18 projecting from each of the surfaces 19a, 19b.

[0085] The presence of the protrusions 18, which are arranged on opposite sides of the cover 10 and in particular on a respective axial surface 19a, 19b of the cover 10, enables a significant improvement and simplification of the manufacturing process of the cover assembly 1: In fact, the covers 10 are mass-produced and, after their manufacture, are often collected in a container, for example a funnel, until they are mounted with the respective base plates 4.

[0086] The elevations 18 significantly reduce, and in particular completely eliminate, the risk of unwanted adhesion between the axial surfaces of two covers 10 that lie side by side in the funnel or accidentally come into contact with each other.

[0087] In other words, the raised areas 18 act as non-stick elements between the covers 10 during manufacturing.

[0088] This avoids the time and cost losses that arise when two or more covers that are stuck together have to be separated before they are mounted with the respective base plates 4.

[0089] Advantageously, each elevation 18 is positioned orthogonally to the main section 10a by a distance which corresponds to 20-40%, preferably 25-35%, more preferably 30%, of the thickness of the main section 10a.

[0090] For example, if the main section 10a has a thickness of 0.5 mm, each elevation 18 projects from it by a distance of 0.15 mm.

[0091] The applicant has determined that these dimensions offer the optimal compromise between non-stick properties and overall dimensions. In fact, thanks to these small dimensions, the cover 10 is essentially flush with the outer surface 15 of the base plate 4.

[0092] Preferably, each elevation 18 has a substantially circular shape.

[0093] This design is the easiest to implement in the manufacturing process. Therefore, the design of the protrusions 18 has no significant impact on the total manufacturing and assembly time required for a cover assembly 1.

[0094] The cover 10 has a central axis B which runs coaxially to the axis A of the injection hole 12 when the cover 10 is attached to the base plate.

[0095] Advantageously, the first elevation 18 and the second elevation 18 are arranged eccentrically on opposite sides of axis B.

[0096] The applicant has determined that this “symmetrical” arrangement in the manufacture supports the aforementioned anti-stick effect to a greater extent compared to other lids 10.

[0097] In an embodiment not shown here, the protrusions 18 may not be arranged symmetrically with respect to axis B.

[0098] In an embodiment not shown here, the elevations 18 can be arranged concentrically to the axis B.

[0099] As in Fig. 2a, Fig. 2b and Fig. As shown in section 3, the coverage includes 10: - a first depression 20, located on the first surface 19a and defining the second elevation 18 on the second surface 19b, and - a second depression 21 located on the second surface 19b and defining the first elevation 18 on the first surface 19a.

[0100] Advantageously, the first protrusion 18 and the first depression 20 on the first surface 19a are arranged eccentrically and on symmetrically opposite sides with respect to the central axis B; similarly, the second protrusion 18 and the second depression 21 on the second surface 19B are arranged eccentrically and on symmetrically opposite sides with respect to the central axis B.

[0101] Advantageously, the injection hole 12 also includes a second recess 22 that surrounds the first recess 17.

[0102] The through hole 16, the first recess 17 and the second recess 22 are formed in the base plate 4.

[0103] As in Fig. As shown in Figure 3, the first depression penetrates 17 deeper into the base plate 4 than the second depression 22.

[0104] Advantageously, the cover 10 is coupled to the second recess 22 and engages in the second recess 22, overlapping the first recess 17.

[0105] In this way, the space 24, which is defined between the surface 19a of the cover 10 and the first recess 17, is enlarged, allowing the sealing pin 13 to engage freely should it partially protrude from the through-hole 16 during use. This reduces stresses and loads on the sealing pin 13, thus ensuring a proper fluid-tight seal during use.

[0106] Advantageously, the circumferential section 10b of the cover 10 is welded to a base surface 23, in particular a lower surface facing the outside, of the second recess 22.

[0107] The applicant has determined that this weld on the base surface 23 of the second recess 22, instead of, for example, on its side surface, results in a higher resistance of the seal and the weld to the thermal and mechanical stresses to which the cover 10 is subjected during use.

[0108] Advantageously, the cover 10 engages in the second recess 22, so that it is essentially flush with the outer surface 15 of the base plate 4.

[0109] Therefore, the presence of the protrusions 18 allows a flat cover 10 to be obtained and used, thereby reducing undesirable excessive dimensions and protrusions of the base plate 4 and thus significantly reducing manufacturing time losses, as the covers 10 do not stick together during manufacturing and / or storage.

[0110] The features of the lid arrangement 1 according to the invention lead to obvious advantages that can be achieved through its use.

[0111] In particular, the presence of the protrusions 18, which are arranged on opposite sides of the cover 10, and especially on a respective axial surface 19a, 19b of the cover 10, enables a significant improvement and simplification of the manufacturing process of the cover arrangement 1: In fact, the covers 10 are mass-produced and, after production, are often collected in a container, for example a funnel, until they are mounted on the respective base plates 4.

[0112] The elevations 18 significantly limit, and in particular completely prevent, the risk of unwanted adhesion between the axial surfaces of two covers 10 that accidentally come into contact with each other in the funnel.

[0113] In other words, the raised areas 18 act as non-stick elements between the covers 10 during manufacturing.

[0114] This avoids the time and cost losses that occur when two or more covers have to be separated from each other before they can be installed.

[0115] At the same time, an essentially flat cover 10 can be used to close the injection hole 12, so that the cover 10 is essentially flush with the base plate 4 and thus any undesirable protrusions or depressions of the same are limited as much as possible.

[0116] Furthermore, this reduction, and in particular the almost complete elimination of unwanted protrusions or indentations (and thus sharp edges) from the outer surface 15 of the base plate 4, leads to another important technical effect: In some cases, the outer surface 15 (and often the entire battery cell) is coated with a film of electrically insulating material (except for the terminals 6); in known sealing elements or covers that have one or more significant protrusions or indentations relative to the outer surface 15 and thus define sharp edges, this insulating film can easily be torn or otherwise damaged by the sharp edges. This has been observed particularly in liquid-cooled battery cells due to pressure fluctuations or pulsations of the liquid itself.

[0117] The substantially flattened design with minimized protrusions and recesses of the cover 10 according to the invention makes it possible to limit or prevent damage to the insulating film, thereby reducing the risk of a short circuit and increasing the service life of the battery cell.

[0118] Finally, the lid arrangement 1 described and shown here can be subjected to changes and variations without exceeding the scope of protection defined in the attached claims.

Claims

[1] Lid arrangement (1) for a battery cell, wherein the lid arrangement (1) is configured to seal an interior (3) of the battery cell in a fluid-tight manner and comprises a base plate (4) configured to seal an opening (3a) of the interior (3); wherein the base plate (4) has an injection hole (12) which allows the injection of an electrolyte material into the interior (3), wherein the lid arrangement (1) further comprises a closure device (8) for fluid-tight sealing of the injection hole (12), wherein the closure device (8) comprises a closure element (10) which is coupled to the base plate (4) at the injection hole (12); wherein the locking element (10) has a substantially flattened configuration and has at least two raised sections (18) arranged on opposite sides of the locking element (10) itself. [2] Lid arrangement (1) according to claim 1, wherein the closure element (10) comprises a main section (10a) and wherein the raised sections (18) project orthogonally from the main section (10a) and thus define elevations (18) that project from the main section (10a). [3] Lid arrangement (1) according to claim 2, wherein each raised section (18) projects orthogonally from the main section (10a) by a distance which corresponds to 20-40%, preferably 25-35%, more preferably 30% of the thickness of the main section (10a). [4] Lid arrangement (1) according to claim 1 or 2 or 3, wherein the closure element (10) has a first surface (19a) facing the injection hole (12) and a second surface (19b) opposite the first surface (19a); wherein the closure element (10) comprises a first raised section (18) located on the first surface (19a) and a second raised section (18) located on the second surface (19b). [5] Lid arrangement (1) according to claim 4, wherein the closure element (10) has a central axis (B); and wherein the first raised section (18) and the second raised section (18) are arranged eccentrically on opposite sides of the central axis (B). [6] Lid arrangement (1) according to claim 4 or 5, wherein the closure element (10) comprises: - a first depression (20) located on the first surface (19a) and defining the second raised section (18) on the second surface (19b), and - a second depression (21) located on the second surface (19b) and defining the first raised section (18) on the first surface (19a). [7] Lid arrangement (1) according to claims 5 and 6, wherein the first raised section (18) and the first recess (20) are arranged eccentrically and on symmetrically opposite sides with respect to the central axis (B) on the first surface (19a); and wherein the second raised section (18) and the second recess (21) are arranged eccentrically and on symmetrically opposite sides with respect to the central axis (B) on the second surface (19B). [8] Cover arrangement (1) according to one of the preceding claims, wherein the injection hole (12) has a central axis (A) and comprises, extending radially from the inside to the outside, a through hole (16), a first recess (17) surrounding the through hole (16), and a second recess (22) surrounding the first recess (17); wherein the first recess (17) penetrates axially deeper into the base plate (4) than the second recess (22); wherein the closure element (10) has a central section (10a) and a circumferential section (10b); and wherein the circumferential section (10b) is welded to a base surface (23) of the second recess (22). [9] Lid arrangement (1) according to claim 8, wherein the base plate (4) has an outer surface (15) on which the injection hole (12) is formed; and wherein the closure element (10) engages in the second recess (22) so that it is arranged substantially flush with the outer surface (15) of the base plate (4). [10] Cover arrangement (1) according to one of the preceding claims, wherein each raised section (18) has a substantially circular shape, and / or wherein the locking element (10) is defined by a disc-shaped body with a substantially circular profile, and / or wherein the closure device (8) further comprises a sealing pin (13) which engages fluid-tight in the injection hole (12), and / or wherein the lid arrangement (1) further comprises at least a connection arrangement (50) configured to be electrically connected on its inside (5) to a respective electrode inside the interior (3) in order to receive electrical energy from it, and configured to be electrically coupled on its outside side (6) to a connector of a device to be energized by the battery cell.

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