Electrochemical cell and battery module comprising such electrochemical cells
By using high-temperature-resistant spacers between terminals and insulators, the electrochemical cell achieves increased energy capacity by reducing terminal thickness and maintaining protection during welding.
Patent Information
- Application Number
- FR2024008605
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2026-02-06
AI Technical Summary
The large thickness of terminals in electrochemical cells, required to protect heat-sensitive components during welding, reduces the available height for electrode stacking and energy capacity.
Incorporation of spacers made of high-temperature-resistant materials between the terminals and insulators, allowing thinner terminals and maintaining protection from welding heat, thereby increasing the available height for electrode stacking.
The solution enables an increase in energy capacity by allowing thinner terminals while protecting insulators from high welding temperatures, thus optimizing the cell's overall energy density.
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Abstract
Description
Title of the invention: Electrochemical cell and battery module comprising such electrochemical cells
[0001] The present invention relates to an electrochemical cell and a battery module comprising such electrochemical cells.
[0002] The invention applies in particular to the manufacture of electrochemical cells, especially for an electric vehicle battery.
[0003] By "battery" is meant a plurality of electrochemical cells electrically connected to one another. According to a particular example of a battery, the plurality of electrochemical cells is arranged in the form of one or more module(s), each module comprising a plurality of electrochemical cells electrically connected to one another and mechanically assembled to one another by an assembly system, such as assembly plates.
[0004] An electrochemical cell includes, in particular, a plurality of electrically connected positive electrodes and a plurality of electrically connected negative electrodes. Specifically, the positive and negative electrodes are stacked alternately. More precisely, an electrode stack is formed by stacking, between two external separators, an alternation of individual positive and negative electrodes separated by separators. The interconnected positive electrodes are electrically connected to a positive terminal, and the interconnected negative electrodes are electrically connected to a negative terminal.
[0005] During the manufacture of battery modules, it is common to connect two adjacent electrochemical cells by means of a busbar between the positive terminal of one cell and the negative terminal of the other cell.
[0006] The busbar is generally fixed to each of these terminals by welding and in particular by laser beam welding.
[0007] During this laser beam welding step, the terminals are subjected to high temperatures, in particular above 600 °C in the area of the melted and resolidified weld bead, and even above 1,000 °C in a very limited area where the laser beam has come into contact.
[0008] In order to protect heat-sensitive components generally present under the terminal, such as an insulator, the terminal is generally manufactured with a sufficiently large thickness.
[0009] However, this large thickness of the terminal reduces the height available for the electrodes and therefore the energy capacity of the cell.
[0010] One object of the invention is to increase the energy capacity of an electrochemical cell, while maintaining the same limited height.
[0011] To this end, an object of the invention is an electrochemical cell comprising:
[0012] - a stack of electrodes,
[0013] - two terminals electrically connected to the electrode stack, each of the two terminals comprising an inner face and an outer face opposite the inner face along an elevation direction of the electrochemical cell, the inner face facing the electrode stack along the elevation direction, and
[0014] - two external insulators, each of the two external insulators comprising a first face and a second face opposite the first face along the elevation direction, the first face of the two insulators respectively facing the inner face of the two terminals.
[0015] The electrochemical cell further comprises two spacers disposed respectively between the first face of the two external insulators and the inner face of the two terminals, each of the two spacers being made of a first material whose melting temperature is greater than 800 °C.
[0016] Each spacer helps protect the corresponding insulator, particularly from the high temperature during welding. Thus, the terminal can be designed with a thinner profile, increasing the available height for electrode stacking and, consequently, the energy capacity of the cell compared to a prior art cell of the same overall height.
[0017] In particular embodiments, the electrochemical cell according to the invention comprises one or more of the following features, taken alone or in any technically feasible combination:
[0018] - The first material has a thermal conductivity of less than 1.0 W / mK.
[0019] - The first material has an absorptivity of less than 0.3 when exposed to a laser beam with a wavelength of less than 1.5 pm.
[0020] - The first material belongs to the mica group.
[0021] - Each of the two spacers has a thickness, measured in the direction of elevation, between 0.05 mm and 0.3 mm.
[0022] - Each of the two terminals has a thickness, measured in the direction of elevation between the inner face and the outer face, less than 2.5 mm.
[0023] - Each of the two insulators is made of plastic.
[0024] - The electrochemical cell is a prismatic electrochemical cell.
[0025] Another object of the invention is a battery module comprising:
[0026] - at least two adjacent electrochemical cells as described above, and
[0027] - at least one busbar electrically connecting one of the two terminals of one of the two electrochemical cells adjacent to one of the two terminals of the other of the two adjacent electrochemical cells.
[0028] In a particular embodiment, said at least one bus bar is welded to the terminal of one of the two adjacent electrochemical cells and to the terminal of the other of the two adjacent electrochemical cells by laser welding.
[0029] The invention will be better understood upon reading the following description, given solely by way of example, and made with reference to the accompanying drawings, in which:
[0030] - [Fig. 1] Fig. 1 is a perspective view of a battery module comprising several electrochemical cells according to the invention, and
[0031] - [Fig.2] [Fig.2] is a cross-sectional view along plane ILII of one of the cells electrochemicals of the [Fig.l].
[0032] A battery module 10 according to the invention will now be described with reference to [Fig.1].
[0033] The battery module 10 is preferably intended to be assembled with other modules to form a battery.
[0034] The battery module 10 is for example intended to be installed in an electric or hybrid motor vehicle (not shown).
[0035] The battery module 10 defines a longitudinal direction X which is for example the direction of movement of the vehicle, and a transverse direction Y perpendicular to the longitudinal direction X which is for example the transverse direction of the vehicle.
[0036] An elevation direction Z, perpendicular to the longitudinal direction X and the transverse direction Y, is also defined; it is intended, for example, to be substantially vertical when the vehicle is on a horizontal surface (not shown).
[0037] The battery module 10 comprises at least two adjacent electrochemical cells 12 comprising two terminals 14A, 14B and at least one bus bar 16 electrically connecting a terminal 14A of one of the electrochemical cells 12 to a terminal 14B of the other electrochemical cell 12.
[0038] In the embodiment illustrated in [Fig.1], the battery module 10 comprises four electrochemical cells 12. The battery module 10 comprises three omnibus bars 16, each connecting two terminals 14A, 14B.
[0039] For example, in the case of [Fig.1], the electrochemical cells 12 are electrically connected in series.
[0040] For example, the electrochemical cells 12 are arranged next to each other along the transverse direction Y.
[0041] Each electrochemical cell 12 comprises at least one stack of electrodes 18.
[0042] In the case of [Fig.2], the cell 12 comprises two stacks of electrodes 18.
[0043] In particular, each stack of electrodes 18 comprises two tabs 44A, one tab for the positive pole and another tab for the negative pole.
[0044] More specifically, the two stacks of electrodes 18 are electrically connected in parallel.
[0045] More specifically, one of the two terminals 14A is for example electrically connected to the positive tabs of the electrode stacks 18 and thus defines a positive terminal 14A for the positive pole of the electrochemical cell 12.
[0046] The other of the two terminals 14B is for example electrically connected to the negative tabs of the electrode stacks 18 and thus defines a negative terminal 14B for the negative pole of the electrochemical cell 12.
[0047] Each electrochemical cell 12 comprises two external insulators 20A and two spacers 22A, each of the two external insulators 20A and each of the two spacers 22A being associated with one of the two terminals 14A, 14B.
[0048] In particular, the pair formed by one of the two external insulators 20A and one of the two spacers 22A is associated with the positive terminal 14A. The pair formed by the other of the two insulators and the other of the two spacers is associated with the negative terminal 14B.
[0049] In [Fig.2], only the pair associated with the positive terminal 14A is shown.
[0050] Preferably, each electrochemical cell 12 is a prismatic electrochemical cell.
[0051] In particular, as shown in [Fig.1], each electrochemical cell 12 comprises a rigid box 24, preferably in the form of a rectangular parallelepiped defining an upper face 25, a lower face 27 and four lateral faces 29, the upper face 25 and the lower face 27 facing each other along the elevation direction Z.
[0052] In the preferred embodiment illustrated in [Fig.2], each electrochemical cell 12 further comprises, for each terminal 14A, 14B, a terminal foot 26A with a terminal barrel, receiving the corresponding terminal 14A.
[0053] In the particular embodiment illustrated in [Fig.2], each post foot 26A with the post barrel has a cross-section in the shape of an inverted "T".
[0054] In the preferred embodiment illustrated in [Fig.2], each electrochemical cell 12 further comprises, for each terminal 14A, 14B, a common top plate 30A, a seal 32A and a common internal insulator 39A, in particular arranged in the corresponding terminal foot 26A with the terminal body.
[0055] On [Fig.2], only the elements 26A, 30A, 32A, 39A associated with the positive terminal 14A are shown.
[0056] Each electrode stack 18 comprises a plurality of electrically connected positive electrodes and a plurality of negative electrodes (not represented) electrically connected to each other. In particular, the positive and negative electrodes are stacked alternately.
[0057] In the preferred embodiment illustrated in [Fig.2], the positive electrodes of each electrode stack 18 are connected to each other, forming a corresponding tab bundle 46A, and are connected to the terminal foot 26A with the terminal barrel associated with the positive terminal 14A.
[0058] Similarly, the negative electrodes of each stack of electrodes 18 are connected to each other, forming a corresponding bundle of tabs, and are connected to the terminal foot with the terminal barrel associated with the negative terminal 14B (not shown in [Fig.2]).
[0059] Each terminal 14A, 14B is electrically connected to each stack of electrodes 18.
[0060] As shown in [Fig.1], each of the two terminals 14A, 14B preferably protrudes partially from the upper face 25 of the box 24.
[0061] Each of the two terminals 14A, 14B is for example assembled with the terminal foot 26A associated with the terminal barrel.
[0062] Each of the two terminals 14A, 14B has, for example, the shape of a rectangular plate.
[0063] Each of the two terminals 14A, 14B comprises an inner face 48A and an outer face 50A opposite to the inner face 48A along the elevation direction Z.
[0064] The inner face 48A of each of the two terminals 14A, 14B faces the stack(s) of electrodes 18, in particular inserted inside the box 24, along the elevation direction Z.
[0065] In the particular embodiment illustrated in [Fig.2], the inner face 48A is turned towards the inside of the box 24.
[0066] The external face 50A of each terminal 14A, 14B is preferably oriented towards the outside of the box 24.
[0067] Advantageously, each of the two terminals 14A, 14B has a thickness tt, measured along the elevation direction Z between the inner face 48A and the outer face 50A, of less than 3.0 mm, preferably less than 2.0 mm, and more preferably between 1.2 mm and 2 mm.
[0068] Each terminal 14A, 14B is for example made of an electrically conductive material, such as copper or aluminum.
[0069] Each of the two external 20A insulators comprises a first face 52A and a second face 54A opposite to the first face 52A along the elevation direction Z.
[0070] The first face 52A of each external isolator 20A faces the internal face 48A of the corresponding terminal 14A, 14B.
[0071] Each external 20A isolator is for example assembled with the 26A terminal base associated with the terminal barrel.
[0072] Each external 20A insulator has, for example, the shape of a rectangular plate.
[0073] Each of the two external 20A insulators includes, for example, an insulating material, such as plastic.
[0074] Preferably, each of the two external 20A insulators is made of plastic.
[0075] Each of the two spacers 22A is disposed between the first face 52A of the corresponding external insulator 20A and the internal face 48A of the corresponding terminal 14A, 14B.
[0076] Preferably, each of the two spacers 22A rests against the first face 52A of the corresponding external insulator 20A and against the internal face 48A of the corresponding terminal 14A, 14B.
[0077] Each spacer 22A advantageously has the shape of a rectangular plate, and is preferably a sheet.
[0078] In other words, each spacer 22A has a thickness ts, measured along the Z elevation direction, significantly smaller than the other two dimensions.
[0079] Preferably, the thickness ts of each of the two spacers 22A is between 0.05 mm and 0.3 mm.
[0080] Each of the two spacers 22A is made of a first material whose melting temperature is greater than 800 °C, and preferably greater than 2500 °C.
[0081] In particular, the first material has a melting temperature between 900 °C and 1500 °C.
[0082] The first material preferably has a thermal conductivity of less than 1.0 W / mK, and preferably less than 0.8 W / mK.
[0083] In particular, the first material has a thermal conductivity between 0.5 W / mK and 0.8 W / mK.
[0084] The first material preferably has an absorptivity of less than 0.3 when exposed to a laser beam of a wavelength less than 1.5 pm.
[0085] In other words, less than 30% of a laser beam with a wavelength less than 1.5 pm incident on the first material is absorbed by it.
[0086] The first material preferably belongs to the mica group.
[0087] As shown in [Fig.2], the common upper plate 30A is arranged between the stack(s) 18 and the corresponding external insulator 20A.
[0088] The corresponding joint 32A and the common internal insulator 39A are preferably arranged between the common top plate 30A and the associated terminal foot 26A with the terminal body.
[0089] Each bus bar 16 is preferably a connection plate made of an electrically conductive material, such as copper or aluminum.
[0090] Each busbar 16 electrically connects the terminals 14A, 14B of two adjacent electrochemical cells 12. In particular, each busbar 16 electrically connects the positive terminal 14A of one of the electrochemical cells 12 to the negative terminal 14B of an adjacent electrochemical cell 12, to allow current to flow between these two cells 12, particularly in the case where the electrochemical cells 12 are electrically connected in series.
[0091] Preferably, each busbar 16 is welded to the corresponding terminals 14A, 14B by laser welding.
[0092] A manufacturing process for a battery module 10 will now be described.
[0093] First, a plurality of electrochemical cells 12 as described above are provided.
[0094] The electrochemical cells 12 are then arranged side by side along the transverse direction Y.
[0095] The method then includes a step of welding at least one bus bar 16 to connect a terminal 14A of one of the electrochemical cells 12 to a terminal 14B of an adjacent electrochemical cell 12.
[0096] In particular, the welding step is carried out by laser welding at a temperature above 600 °C.
[0097] Thanks to the 22A spacers, the two external 20A insulators are protected from the high temperature of welding during the welding stage.
[0098] Consequently, the thickness of each of the two terminals 14A, 14B can be designed without taking into account the protection of the two external 20A insulators, and can therefore be reduced.
[0099] In particular, the reduction in height due to the reduction in the thickness tt of each of the two terminals 14A, 14B is greater than the increase in height due to the addition of the thickness ts of each of the two spacers 22A.
[0100] Thus, the height (He) available for the stacking(s) of electrodes 18 for the same total height (H) has increased compared to the prior art.
[0101] The energy capacity of the electrochemical cell 12 was therefore able to be increased thanks to the spacers 22A. References
[0102] 10 - Battery module
[0103] 12 - Electrochemical cell
[0104] 14A, 14B - Terminal
[0105] 16 - Bus stop
[0106] 18 - Electrode stack
[0107] 20A - External isolator
[0108]
[0109]
[0110] [YES]
[0112]
[0113]
[0114]
[0115]
[0116]
[0117]
[0118]
[0119]
[0120]
[0121]
[0122] 22A - Spacer 24 - Box 25 - Top face 26A - Terminal base with terminal lock 27 - Bottom face 29 - Side face 30A - Top plate 32A - Sealing gasket 39A - Internal insulator 44A - Tab 46A - Tab group 48A - Inner face 50A - Outer face 52A - First face 54A - Second face
Claims
Demands
1. Electrochemical cell (12) comprising: - an electrode stack (18), - two terminals (14A, 14B) electrically connected to the electrode stack (18), each of the two terminals (14A, 14B) comprising an inner face (48A) and an outer face (50A) opposite the inner face (48A) along an elevation direction (Z) of the electrochemical cell (12), the inner face (48A) facing the electrode stack (18) along the elevation direction (Z), and - two external insulators (20A), each of the two external insulators (20A) comprising a first face (52A) and a second face (54A) opposite the first face (52A) along the elevation direction (Z), the first face (52A) of the two insulators (20A) respectively facing the inner face (48A) of the two terminals (14A, 14B),characterized in that the electrochemical cell (12) further comprises two spacers (22A) respectively disposed between the first face (52A) of the two external insulators (20A) and the inner face (48A) of the two terminals (14A, 14B), each of the two spacers (22A) being made of a first material having a melting point above 800 °C.
2. Electrochemical cell (12) according to claim 1, wherein the first material has a thermal conductivity of less than 1.0 W / mK.
3. Electrochemical cell (12) according to claim 1 or 2, wherein the first material has an absorptivity of less than 0.3 when exposed to a laser beam of a wavelength less than 1.5 pm.
4. Electrochemical cell (12) according to any one of claims 1 to 3, wherein the first material belongs to the mica group.
5. Electrochemical cell (12) according to any one of claims 1 to 4, wherein each of the two spacers (22A) has a thickness (ts), measured along the elevation direction (Z), of between 0.05 mm and 0.3 mm.
6. Electrochemical cell (12) according to any one of claims 1 to 5, wherein each of the two terminals (14A, 14B) has a thickness (tt), measured along the elevation direction (Z) between the inner face (48A) and the outer face (50A), of less than 2.5 mm.
7. Electrochemical cell (12) according to any one of claims 1 to 6, wherein each of the two insulators (20A) comprises plastic.
8. Electrochemical cell (12) according to any one of claims 1 to 7, wherein the electrochemical cell (12) is a prismatic electrochemical cell.
9. Battery module (10) comprising: - at least two adjacent electrochemical cells (12) according to any one of claims 1 to 8, and - at least one bus bar (16) electrically connecting one of the two terminals (14A) of one of the two adjacent electrochemical cells (12) to one of the two terminals (14B) of the other of the two adjacent electrochemical cells (12).
10. Battery module (10) according to claim 9, wherein said at least one bus bar (16) is welded to terminal (14A) of one of the two adjacent electrochemical cells (12) and to terminal (14B) of the other of the two adjacent electrochemical cells (12) by laser welding.
Citation Information
Patent Citations
Battery cells, batteries and electrical devices
CN117199729B
Battery cover plate, lithium ion battery with same and power device
CN217656042U
Battery pack and manufacturing method for battery pack
JP2020115418A