Lid assembly for a prismatic battery cell

Abstract

There is described a lid assembly (1) for a battery cell which internally defines an inner compartment (3), the lid assembly (1) comprising a base plate (4) configured to close the inner compartment (3); a current collector (5) configured to be electrically connected to a respective electrode of the battery cell within the inner compartment (3); a terminal member (6) electrically connected with the current collector (5); and a terminal pin (7) coupled with both the current collector (5) and the terminal member (6) for electrically connecting the current collector (5) with the terminal member (6); the terminal pin (7) includes an exposed surface (13) facing, in use, the external environment; the lid assembly (1) further comprises a cover (14) completely covering said exposed surface (13).

Description

[0001] LID ASSEMBLY FOR A PRISMATIC BATTERY CELL

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No . 102024000021250 filed on September 24 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field

[0005] The present invention relates to a lid assembly for a battery cell , in particular a lid assembly for closing and sealing in a fluid-tight manner an inner compartment of a prismatic battery cell housing electrodes and electrolytic material .

[0006] Background Art

[0007] Battery cells are known, which are used as electrical energy accumulators .

[0008] In particular, so-called primary batteries are known, which cannot be easily recharged and are therefore destined to single-use , and so-called secondary batteries are known, which can be repeatedly charged after each cycle of usage .

[0009] Single-cell batteries of the secondary type are known which are used for various portable small-si zed electronic devices , such as cellular phones , watches , smartwatches , smartbands , etc .

[0010] Also , batteries which include a plurality of cells connected in series or in parallel are known, for example as used in the automotive industry .

[0011] The present invention will refer to a battery cell for the use in a battery of a hybrid or full electric vehicle , without however losing generality . Secondary battery cells can be manufactured as various types , such as cylindrical or prismatic cells .

[0012] The present invention will refer to a prismatic battery cell , without however losing generality .

[0013] A prismatic battery cell typically comprises a hollow prismatic casing, for example in the shape of a parallelepiped and usually made of metallic material , and two electrodes ( cathode and anode ) housed within the casing, which then defines an inner compartment of the cell .

[0014] The compartment also houses a separator material electrically interposed between the two electrodes .

[0015] Within the compartment , the electrodes and the separator are immersed in an electrolytic solution, usually liquid or gelatinous .

[0016] The battery cell also comprises at least one lid assembly which is coupled to the casing for closing the compartment .

[0017] More speci fically, the casing usually has at least one opening ( for example a rectangular opening) , normally located on its top, through which the electrodes , separator and electrolytic solution are inserted into the compartment . The lid assembly ( for example a substantially rectangular-shaped lid assembly) is coupled to the casing for closing such opening .

[0018] The lid assembly typically comprises : a base plate , typically metallic and made of aluminum, arranged to match and engage the opening of the casing for the closing thereof ;

[0019] - a current collector for each electrode , which is electrically connected to the relative electrode and is configured to collect the electric energy form such electrode and feed it from the inner compartment towards the outside environment ; and

[0020] - a terminal member for each electrode , which is electrically connected with the respective current collector for receiving the electric energy therefrom, and which is configured to receive a connector of a consumer device which has to be powered by the battery cell .

[0021] The terminal member and the current collector are usually coupled ( electrically and mechanically) with one another via a terminal pin, which engages a respective through hole obtained in the base plate .

[0022] In particular, the terminal pin is usually welded to the current collector and is coupled to the terminal member by engaging a through hole obtained in the terminal member itsel f .

[0023] In light of the above , the terminal member is arranged on a first external side of the base plate and thus faces outwards , whereas the current collector is arranged on a second internal side of the base plate , opposite the first side , and thus faces inwards , i . e . towards the inner compartment .

[0024] Hence , the terminal member, the terminal pin and the current collector define together a terminal group of the lid assembly . Usually, both the current collector and the terminal member are defined by respective metallic plates . The current collector defines a foot plate of the terminal group . The terminal member defines a head plate of the terminal group .

[0025] The lid assembly further comprises a seal element for each collector member, which is made of resilient and electrically insulating material and which serves the twofold function of : electrically insulating the collector member and the terminal pin from the base plate and f luid-tightly sealing the inner compartment from the outside environment .

[0026] To this end, the seal element is mechanically interposed between the respective collector member / terminal pin and the base plate , so that the collector member and the terminal pin are not arranged in direct contact with the base plate , but still being mutually coupled thereto with the interposition of the seal element itsel f .

[0027] The lid assembly further comprises an insulator member interposed between the terminal member and the base plate for electrically insulating the terminal member from the base plate .

[0028] In some configurations , the casing has two openings , one for each electrode , for example two lateral openings . In this case , the battery has two lateral lid assemblies , one for each electrode .

[0029] In light of the above , the lid assembly seals the inner compartment in a fluid-tight manner .

[0030] According to a known operative configuration, the battery cell may need to be immersed, during use, in a cooling fluid for ensuring a nominal operating temperature of the battery cell .

[0031] Typically, thermally controlling oils , such as mineral oil , ester-based oils , and phosphoric ester-based oils are used as cooling fluids .

[0032] It is also widely known that while the collector member and the terminal pin of the cathode electrode are made of aluminum, the collector member and the terminal pin of the anode electrode must be made of copper .

[0033] However, in case the aforementioned immersion cooling is used to cool the battery cells , the thermally controlling oils may react with copper, thereby leading over time to a corrosion of the exposed surface of the terminal pin engaging the aforementioned through hole in the terminal member .

[0034] Disclosure of Invention

[0035] It is therefore an obj ect of the present invention to provide a lid assembly for a battery cell which is designed to overcome the above-mentioned drawback in a straightforward and low-cost manner .

[0036] This obj ect is achieved by a lid assembly for a battery cell as claimed in the appended independent claim 1 . Preferred embodiments of the present invention are laid down in the appended dependent claims .

[0037] Brief Description of the Drawings

[0038] A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings , in which :

[0039] Figure 1 is an exploded perspective view, with parts removed for clarity, of a lid assembly for a battery cell according to the present invention; and

[0040] Figure 2 is a sectioned view, with parts removed for clarity, of a terminal area of the lid assembly of Figure 1 .

[0041] Best Mode for Carrying Out the Invention

[0042] With reference to Figure 1 , number 1 indicates as a whole a lid assembly for a battery cell . The present invention will refer, without however losing generality, to a lid assembly 1 for a prismatic battery cell .

[0043] In particular, the battery cell is of the prismatic type and has a hollow prismatic casing 2 which internally defines an inner compartment 3 and which presents an opening 3a to access inner compartment 3 .

[0044] According to the embodiment shown, casing 2 has a parallelepiped shape . Alternatively, casing 2 may have any prismatic shape , such as cubic, triangular-based, etc .

[0045] In one embodiment , casing 2 could be cylindrical . In such a case , lid assembly 1 has a round ( circular ) configuration .

[0046] The present invention will refer to a battery cell for use in the automotive industry, for example in a battery module of a hybrid or full-electric vehicle , without however losing generality .

[0047] The battery cell further comprises electrodes ( cathode and anode , not shown) , which are housed in inner compartment 3 together with separator material (not shown) and an electrolytic material (not shown) .

[0048] The electrolytic material may be liquid or gelatinous .

[0049] The electrodes and the separator material are inserted into inner compartment 3 from opening 3a .

[0050] Accordingly, lid assembly 1 is configured to be coupled with casing 2 at opening 3a for f luid-tightly closing inner compartment 3 , as required during the normal use of the battery cell .

[0051] Hence , the battery cell comprises casing 2 , with the electrodes , the separator and the electrolytic solution, and lid assembly 1 .

[0052] The battery cell is preferably part of a battery module including a plurality of battery cells electrically connected to one another in parallel , for example to power an electric motor of a vehicle .

[0053] Casing 2 may comprise a further opening 3a opposite to the aforementioned opening 3a, as indicated in Figure 1 . In such a case , a further lid assembly 1 (not shown) is to be coupled with casing 2 so as to f luid-tightly close the further opening 3a .

[0054] Openings 3a may be placed on the top and bottom sides of casing 2 , as shown in Figure 1 , or alternatively on the lateral sides of casing 2 .

[0055] In the following, reference will be made to a single lid assembly 1 , for the sake of brevity . The structural and functional features of such lid assembly 1 are however applicable to each lid assembly 1 which may be present in the battery cell .

[0056] As visible in Figure 1 , lid assembly 1 comprises a base plate 4 made of metallic material , such as aluminum or stainless steel , and configured to be coupled to casing

[0057] 2 at opening 3a for closing opening 3a of inner compartment 3 .

[0058] That is , base plate 4 is arranged to match the shape of , and engage , opening 3a for closing inner compartment

[0059] 3 .

[0060] Lid assembly 1 further comprises a terminal group 50 ( Figure 2 ) configured to be electrically connected, at an inner side 5 thereof , to a respective electrode within inner compartment 3 for collecting electrical energy therefrom and configured to be electrically coupled, at an outer side 6 thereof , with a connector of a device (not shown) to be powered by the battery cell .

[0061] In particular, terminal group 50 has a longitudinal axis A and includes : a current collector 5 which defines the aforementioned inner side of terminal group 50 and is configured to be electrically connected to the respective electrode , for collecting electrical energy therefrom and trans ferring it from inner compartment 3 outwards ; a terminal member 6 which defines the aforementioned outer side of terminal group 50 and is configured to be electrically coupled with the aforementioned connector ; and a terminal pin 7 which is axially interposed between current collector 5 and terminal member 6 and electrically connects these latter to one another .

[0062] Preferably, terminal pin 7 is substantially cylindrical and is arranged coaxially to axis A.

[0063] In detail , pin 7 is coupled with both current collector 5 and terminal member 6 for electrically connecting current collector 5 with terminal member 6 .

[0064] In greater detail , terminal pin 7 is welded, at one axial side thereof , to terminal member 6 and, at the opposite axial side thereof , to current collector 5 .

[0065] Hence , pin 7 couples mechanically, and connects electrically, terminal member 6 with collector 5 .

[0066] Terminal member 6 is mechanically coupled to pin member 7 , so as to establish said electric connection .

[0067] Terminal group 50 extends along the axial direction from inner compartment 3 to an outer environment external to inner compartment 3.

[0068] In detail, terminal member 6 is arranged at an outer side of the base plate 4 (i.e. the side facing the outer environment) , so as to be connected to the connector, and the collector 5 is arranged at an inner side of the base plate 4 (i.e. the side facing inner compartment 3) , so as to be connected with the respective electrode.

[0069] Opportunely, base plate 4 has a through hole 4a, which is engaged by terminal pin 7.

[0070] In light of the above, current collector 5 and terminal member 6 are arranged on opposite sides of base plate 4, with respect to the axial direction.

[0071] Opportunely, terminal member 6 has a through hole 6a engaged (in contact) by pin 7, until terminal member 6 rests on an outer wall 4b of base plate 4, conveniently with the interposition of an electrically insulating gasket 8, so that terminal member 6 and base plate 4 are electrically insulated from one another. Opportunely, also gasket 8 includes a trough hole 8a for allowing the passage of pin 7.

[0072] Through holes 4a, 6a and 8a are expediently coaxial with pin 7.

[0073] Conveniently, lid assembly 1 further comprises:

[0074] - a stop frame 10 made of an electrically insulating material (such as rigid plastic) , known per se and not described in detail;

[0075] - a pour opening Ila obtained in base plate 4 through which the electrolytic material is to be inserted; and

[0076] - a cap 11b for closing pour opening 13a.

[0077] Lid assembly 1 may comprise two or more terminal groups 50. In the following, only one terminal group 50 will be considered, for the sake of brevity .

[0078] Lid assembly 1 further comprises an elastomeric sealing member 12 arranged between base plate 4 and terminal group 50 and configured to define a fluid-tight seal between inner compartment 3 and the outer environment external to inner compartment 3 .

[0079] Sealing member 12 has also the function of electrically insulating base plate 4 from terminal group 50 .

[0080] To this end, sealing member 12 is axially interposed between base plate 4 and current collector 5 .

[0081] Conveniently, sealing member 12 has an annular shape and is arranged around pin 7 , coaxially with axis A.

[0082] That is , pin 7 engages the annular sealing member 12 , coaxially to axis A.

[0083] In detail , sealing member 12 is defined by an L- shaped ring and is interposed axially between base plate 4 and current collector 5 .

[0084] Sealing member 12 may be defined by an o-ring .

[0085] Sealing member 12 is configured for preventing an outflow of electrolytic material from inner compartment 3 outwards , as well as the entrance of external substances ( dirt , water, etc ) into inner compartment 3 .

[0086] As visible in Figure 1 and particularly in Figure 2 , pin 7 includes an exposed surface 13 facing, in use, the external environment .

[0087] That is exposed surface 13 is opposite to inner compartment 3 .

[0088] As visible in the Figures , pin 7 engages through hole 6a of terminal member 6 so that exposed surface 13 is located in through hole 6a and faces the external environment from through hole 6a .

[0089] In particular, pin 7 includes a lateral surface 7a engaging ( in contact ) through hole 6a .

[0090] In light of the above , exposed surface 13 is axial , relatively to axis A.

[0091] According to the present invention, lid assembly 1 further comprises a cover 14 completely covering exposed surface 13 .

[0092] In particular, cover 14 f luid-tightly seals pin 7 ( and therefore exposed surface 13 ) from the external environment .

[0093] For the purpose of the present invention, the anode terminal group 50 is hereby considered .

[0094] That is , terminal group 50 as described above , is the terminal group which is electrically connected to the anode electrode of the aforementioned two electrodes which are housed in inner compartment 3 .

[0095] Therefore , current collector 5 i s configured to be electrically connected to the anode of the battery cell .

[0096] Hence , due to a known constructional and functional need, current collector 5 and terminal pin 7 are conveniently made of copper .

[0097] Terminal member 6 is instead made of aluminum, according to a known configuration .

[0098] According to a known operative configuration, the battery cell may need to be immersed, during use , in a cooling fluid for ensuring a nominal operating temperature of the battery cell .

[0099] Typically, thermally controlling oils , such as mineral oil , ester-based oils , and phosphoric ester-based oils are used as cooling fluids . Such thermally controlling oils may react with copper, thereby leading over time to a corrosion of exposed surface 13 .

[0100] Thanks to the presence of cover 14 , the cooling fluid is prevented to contact the copper pin 7 .

[0101] In this way, a corrosion of the copper pin 7 is prevented and the li fespan thereof is increased .

[0102] Advantageously, cover 14 is made of aluminum .

[0103] The Applicant has found that aluminum does not react with the aforementioned cooling fluid, and does not incur in any corrosion due to the interaction with the cooling fluid .

[0104] In this way, the electric conductivity of terminal member 6 is not hindered or limited or decreased, while at the same time enabling to protect the copper pin 7 .

[0105] According to an alternative embodiment , cover 14 may be made in a material other than aluminum and which does not react with the cooling fluid .

[0106] The cover 14 made of aluminum represents the preferred embodiment , due to the fact that in this way an optimal electric conductivity of terminal member 6 is preserved .

[0107] According to a preferred embodiment of the present invention, lid assembly 1 comprises a cap or lid member 14 coupled to pin 7 , or to terminal member 6 at pin 7 , so as to cover exposed surface 13 .

[0108] Cap member 14 defines the aforementioned cover .

[0109] In detail , cap member 14 is coupled to an outer surface of terminal member 6 at through hole 6a, thereby closing the through hole 6a .

[0110] Hence , cap member 14 closes through hole 6a in a fluid-tight manner .

[0111] Conveniently, cap member 14 is welded to terminal member 6 , preferably by laser welding .

[0112] Alternatively, cap member 14 is welded to pin 7 , by laser welding .

[0113] Expediently, terminal member 6 is provided with a recess 15 on its outer surface .

[0114] Recess 15 surrounds through hole 6a .

[0115] Accordingly, cap member 14 is coupled to terminal member 6 engaging recess 15 , and is welded thereto .

[0116] In this way, the encumbrance of cap member 14 is reduced .

[0117] Advantageously, cap member 14 engages recess 15 in such a way that an outer wall of cap member 14 is flush with the outer surface of terminal member 6 .

[0118] In this way, an excessive raised protrusion on lid assembly 1 is avoided, which could hinder the assembly and / or stacking of various battery cells together, as it is the case in the automotive applications .

[0119] According to an alternative embodiment (not shown) of the present invention, lid assembly 1 comprises a layer of sheet material wrapping at least exposed surface 13 , the layer of sheet material defining cover 14 .

[0120] Thanks to this configuration, the overall si ze of pin 7 is reduced, and the original architecture of terminal group 50 is substantially preserved, as the sheet of material is very thin compared to cap member 14 .

[0121] According to a further alternative embodiment (not shown) the present invention, pin 7 includes a coating located at least at exposed surface 13 , so that exposed surface 13 is completely coated by the coating, the coating defining cover 14 .

[0122] Preferably, the coating is also located at at least a portion of lateral surface 7a proximal to exposed surface 13 .

[0123] Even more preferably, the coating is provided on the entirety of lateral surface 7a .

[0124] In light of the above , it is stated that , in the present description and in the appended claims , the term "cover" encompasses a cap member 14 as the one shown in the Figures , a layer of sheet material , and a coating .

[0125] Thanks to this configuration, the total number of components of lid assembly 1 is not varied, lid assembly 1 has less components compared to the case in which a cap member 14 or a layer of sheet material is used, and the assembly thereof is thus simpli fied .

[0126] The advantages o f lid assembly 1 according to the present invention will be clear from the foregoing description .

[0127] In particular, thanks to the presence of cover 14 , which may be in the form of a cap member, of a layer of sheet material or of a coating, the pin 7 is protected from the external environment .

[0128] More in particular, pin 7 is f luid-tightly sealed from the external environment .

[0129] This is particularly advantageous in the case in which the battery cell is to be cooled by a cooling fluid, such as a thermally controlling oil , which may be detrimental to the material of pin 7 .

[0130] In fact , due to cover 14 , the cooling fluid is prevented to contact pin 7 , and especially the exposed surface 13 thereof . As said, this is particularly, but not necessarily exclusively, advantageous for the anode terminal group 50 , whereby the pin 7 is made of copper .

[0131] In this way, a corrosion of the copper pin 7 is prevented and the li fespan thereof is increased .

[0132] Clearly, changes may be made to lid assembly 1 as described herein without , however, departing from the scope of protection as defined in the accompanying claims .

Claims

CLAIMS1.- Lid assembly (1) for a battery cell having a casing (2) which internally defines an inner compartment (3) for housing electrodes and an electrolytic material and which has at least one opening (3a) for accessing the inner compartment (3) , the lid assembly (1) being configured to f luid-tightly seal the inner compartment (3) from an external environment, the lid assembly (1) comprising :- a base plate (4) configured to close the opening (3a) of the inner compartment (3) ; a current collector (5) configured to be electrically connected to a respective electrode of the battery cell within the inner compartment (3) for collecting electrical energy therefrom and transferring it from the inner compartment (3) outwards;- a terminal member (6) electrically connected with the current collector (5) for receiving the electrical energy therefrom and configured to be electrically coupled with a connector of a consumer device which is to be powered by the battery cell; and- a terminal pin (7) coupled with both the current collector (5) and the terminal member (6) for electrically connecting the current collector (5) with the terminal member ( 6 ) ; wherein the terminal pin (7) includes an exposed surface (13) facing, in use, the external environment; wherein the terminal member (6) has a through hole (6a) , the terminal pin (7) engaging the through hole (6a) so that the exposed surface (13) is located in the through hole (6a) and faces the external environment from thethrough hole (6a) ; wherein the lid assembly (1) further comprises: a cover (14) completely covering said exposed surface ( 13 ) ;- a cap member (14) coupled to the terminal pin (7) , or to the terminal member (6) at said terminal pin (7) , so as to cover the exposed surface (13) , the cap member (14) defining said cover; and wherein the cap member (14) closes the through hole (6a) in a fluid-tight manner.2.- Lid assembly as claimed in claim 1, wherein said cover (14) f luid-tightly seals the terminal pin (7) from the external environment.3.- Lid assembly as claimed in claim 1 or 2, wherein the cap member (14) is welded to the terminal member (6) and / or to the terminal pin (7) , preferably by laser welding .4.- Lid assembly (1) for a battery cell having a casing (2) which internally defines an inner compartment (3) for housing electrodes and an electrolytic material and which has at least one opening (3a) for accessing the inner compartment (3) , the lid assembly (1) being configured to f luid-tightly seal the inner compartment (3) from an external environment, the lid assembly (1) comprising :- a base plate (4) configured to close the opening (3a) of the inner compartment (3) ; a current collector (5) configured to be electrically connected to a respective electrode of the battery cell within the inner compartment (3) for collecting electrical energy therefrom and transferringit from the inner compartment (3) outwards;- a terminal member (6) electrically connected with the current collector (5) for receiving the electrical energy therefrom and configured to be electrically coupled with a connector of a consumer device which is to be powered by the battery cell; and- a terminal pin (7) coupled with both the current collector (5) and the terminal member (6) for electrically connecting the current collector (5) with the terminal member ( 6 ) ; wherein the terminal pin (7) includes an exposed surface (13) facing, in use, the external environment; and wherein the lid assembly (1) further comprises a cover (14) completely covering said exposed surface (13) ; wherein the lid assembly (1) comprises a layer of sheet material wrapping at least said exposed surface(13) , the layer of sheet material defining said cover(14) .5.- Lid assembly (1) for a battery cell having a casing (2) which internally defines an inner compartment (3) for housing electrodes and an electrolytic material and which has at least one opening (3a) for accessing the inner compartment (3) , the lid assembly (1) being configured to f luid-tightly seal the inner compartment (3) from an external environment, the lid assembly (1) comprising :- a base plate (4) configured to close the opening (3a) of the inner compartment (3) ; a current collector (5) configured to be electrically connected to a respective electrode of thebattery cell within the inner compartment (3) for collecting electrical energy therefrom and transferring it from the inner compartment (3) outwards;- a terminal member (6) electrically connected with the current collector (5) for receiving the electrical energy therefrom and configured to be electrically coupled with a connector of a consumer device which is to be powered by the battery cell; and- a terminal pin (7) coupled with both the current collector (5) and the terminal member (6) for electrically connecting the current collector (5) with the terminal member ( 6 ) ; wherein the terminal pin (7) includes an exposed surface (13) facing, in use, the external environment; and wherein the lid assembly (1) further comprises a cover (14) completely covering said exposed surface (13) ; wherein the terminal pin (7) includes a coating located at least at said exposed surface (13) , so that the exposed surface (13) is completely coated by the coating, the coating defining said cover (14) .6.- Lid assembly as claimed in claim 5, wherein the terminal member (6) has a through hole (6a) , the terminal pin (7) engaging the through hole (6a) so that the exposed surface (13) is located in the through hole (6a) and faces the external environment from the through hole (6a) ; wherein the terminal pin (7) includes a lateral surface (7a) engaging the through hole (6a) ; and wherein the coating is also located at at least a portion of said lateral surface (7a) proximal to the exposed surface (13) .7 Lid assembly as claimed in any one of the foregoing claims, wherein said cover (14) is made of aluminum.8.- Lid assembly as claimed in any one of the foregoing claims, wherein the current collector (5) and the terminal pin (7) are made of copper.

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