EP-4738534-A1 - ELECTRIC BATTERY PACK WITH CYLINDRICAL OR POUCH CELLS, AND WITH AN IMMERSION-TYPE THERMAL MANAGEMENT SYSTEM INCLUDING AN IMPROVED SEALING DEVICE

Abstract

An electric battery pack (1) comprises one or more groups of battery cells (2) arranged inside a container (4). The battery cells (2) are cylindrical cells (2) or pouch cells arranged horizontally and immersed in a flow of a temperature-regulating liquid that maintains them within a predetermined temperature range. The temperature-regulating liquid flows from an inlet collector chamber (5), situated below the battery cells (2), through spaces (7) defined between the cells (2), into an outlet collector chamber (6) arranged above the cells. The spaces between the cells communicate with the inlet collector chamber (5) via a plurality of restricted passages (9). The battery cells (2) each have their respective positive and negative poles (P, N) situated at a same end, or on opposite ends, of the cell, facing a respective vertical side wall (40) of the container (4). All the poles (P, N) of the cells that are facing a respective vertical side wall (40) of the container (4) of the battery pack (1) are contained in one or more lateral chambers (C). The temperature-regulating liquid can flow from the inlet collector chamber (5) to the outlet collector chamber (6) also passing through the lateral chambers (C), which are isolated from the spaces (7) between the cells (2) by means of a separation wall (D) including a sealing panel (10) of elastomeric material, for example of silicone material, mounted on the ends of the cells (2) bearing the poles (P, N). Associated with the sealing panel (10) and/or with a rigid support frame (11) of the sealing panel are one or more rigid tubular elements (12) for the communication of the inlet collector chamber (5) with each lateral chamber (C).

Inventors

• RICCO, RAFFAELE
• VURRO, Luca
• LORUSSO, Eligio
• TRENTADUE, Maurizio Filippo
• DE MICHELE, ONOFRIO
• MAZZARELLA, CARLO

Assignees

• C.R.F. Società Consortile per Azioni

Dates

Publication Date

20260506

Application Date

20251022

Claims (3)

1. Electric battery pack, comprising one or more groups of battery cells (2), arranged inside a container (4), wherein the container (4) is configured to be traversed by a flow of a temperature-regulating liquid that is intended to come into direct contact with the battery cells (2) to maintain them within a predetermined temperature range, wherein the battery pack (1) comprises a distribution system for the temperature-regulating liquid, including: an inlet opening (5A) for the temperature-regulating liquid, communicating with an inlet collector chamber (5), arranged below the battery cells (2), an outlet opening (6A) for the temperature-regulating liquid, communicating with an outlet collector chamber (6) arranged above the battery cells (2), wherein the inlet collector chamber (5) and the outlet collector chamber (6) communicate with each other via spaces (7) defined between the battery cells (2), wherein the spaces (7) defined between the battery cells (2) communicate with the inlet collector chamber (5), situated below the battery cells (2), via a plurality of relatively restricted passages (9), configured to oppose sufficient resistance to the flow of the temperature-regulating liquid to prevent a tendency of the temperature-regulating liquid to flow to a greater extent in the spaces (7) between the battery cells (2) that are closer to said inlet opening (5A) and/or to said outlet opening (6A), wherein the battery cells (2) are cylindrical or pouch cells arranged with their main axis directed horizontally and with their respective positive and negative poles (P, N) situated at a same end, or on opposite ends, of the cell, facing a respective vertical side wall (40) of the container (4), wherein all the poles of the cells that are facing a respective vertical side wall (40) of the container (4) of the battery pack (1) are contained in one or more lateral chambers (C) inside the container (4), which are isolated from the spaces (7) between the cells (2), wherein said one or more lateral chambers (C) containing the poles (P, N) of the cells (2) communicate with the inlet collector chamber (5) and with the outlet collector chamber (6), whereby the temperature-regulating liquid can flow from said inlet collector chamber (5) to said outlet collector chamber (6) also passing through said one or more lateral chambers (C), wherein said one or more lateral chambers (C) containing the poles (P, N) of the cells, are hydraulically isolated from the spaces (7) between the cells (2) by means of a separation wall (D) including a sealing panel (10) of elastomeric material, preferably of silicone material, mounted on the ends of the cells (2) bearing the poles (3P, 3N), and further including a rigid frame (11) for supporting the sealing panel (10), which is rigidly connected to the container (4), wherein, associated with the sealing panel (10) are one or more rigid tubular elements (12) for the communication of the inlet collector chamber (5) with each lateral chamber (C), said one or more tubular elements being incorporated into the sealing panel (10) and into the support frame (11).
2. Battery pack according to claim 1, wherein the battery cells are cylindrical cells (2) which are supported by internal vertical walls (T) of the container (4) each having a plurality of apertures through which the cylindrical cells are arranged, and wherein the apertures of said vertical support walls (T) are configured and arranged such that the cylindrical cells (2) are supported in positions spaced apart from each other, arranged side by side parallel to each other in multiple superimposed levels.
3. Battery pack according to claim 2, characterized in that said vertical walls (T) for supporting the cylindrical cells (2) each have auxiliary apertures (A) for the passage of the temperature-regulating liquid from one side to the other of the support wall (T).

Description

Field of the invention The present invention relates to the field of electric batteries, in particular to electric batteries for powering traction electric motors of electric or hybrid vehicles. Even more particularly, the invention relates to battery packs of the type in which the battery cells are in direct contact with a flow of a temperature-regulating liquid, typically a dielectric oil, which flows through the battery pack for the purpose of maintaining the battery cells within a predetermined temperature range, so as to ensure correct and safe operation of the battery pack under all operating and environmental conditions. Background of the invention The Applicant has already proposed various solutions in the field of thermal management systems for electric battery packs. See, for example, the Italian patent applications 102023000022692, 102023000022698, 102023000022704, 102023000025884, 102024000002776, 102024000002779, 102024000004423, 102024000007807, 102024000007813, 102024000007816, 102024000007828, 102024000013039, 102024000013492, 102024000014308, 102024000014314, 102024000014326, 102024000015637, 102024000016354, 102024000016933, 102024000020863, 102024000020875, 102024000021069, 102024000021546, 102024000022857, all still not available to the public as of the date of the present invention. Figure 1 of the attached drawings shows an example of a battery module 1 of a type per se known, to which the present invention is applicable. The battery module 1 comprises an aligned array of battery cells 2 of the prismatic type illustrated in figure 2. This type of battery cell includes a housing with a top wall 2A, from which the positive and negative poles or "tabs" 3P and 3N of the cell 2 protrude, two main walls 2B (only one of which is visible in figure 2), two end walls 2C (only one of which is visible in figure 2) and a bottom wall 2D. In battery modules of the type described above, the battery cells 2 are arranged within a sealed container 4 and are immersed in a flow of a dielectric temperature-regulating liquid, for example an oil. The container 4 defines internally an inlet collector chamber 5 (schematically illustrated in figure 3) arranged below the cells 2, and an outlet collector chamber 6 (also schematically illustrated in figure 3) arranged above the cells 2. The container 4 has an inlet 5A and an outlet 6A for the temperature-regulating liquid, communicating respectively with the inlet collector chamber 5 and with the outlet collector chamber 6. P and N indicate the positive pole and the negative pole of the battery module 1. Generally, the inlet 5A is always arranged below the cells 2, while the outlet 6A is arranged above the cells 2, to allow any air bubbles formed within the fluid to be collected in the upper collector chamber. However, this layout is not the only possible one; the inlet and outlet can be swapped when an inlet pressure can be guaranteed to avoid any form of fluid evaporation. Battery modules of the type illustrated in figure 1 are used to make battery packs intended to power traction electric motors of electric or hybrid vehicles. In use, the temperature-regulating liquid enters the inlet collector chamber 5, arranged below the battery cells 2, and reaches the outlet collector chamber 6, arranged above the battery cells 2, by passing through a plurality of passages 7, provided between the battery cells 2. In figure 3, the dimensions of the passages 7, provided between the battery cells 2, have been exaggerated for clarity. In general, it is of fundamental importance to ensure that during the use of the electric vehicle, the battery cells are always at a temperature contained within a predetermined range, typically between a minimum threshold of 20° C and a maximum threshold of 55° C. The battery cells used in electric vehicles are typically lithium-ion battery cells, which tend to generate heat as a result of the chemical reaction that takes place inside the battery cells during operation, and also due to the Joule effect, due to the passage of current inside the battery. The term "battery operation" here refers to both the battery charging process and the discharging process, which typically occurs during vehicle travel. It is necessary to consider that the most critical operating conditions of the battery are those related to the fast charging process, i.e., charging the battery in a time of less than one hour. During normal operating conditions of the battery unit, the temperature-regulating liquid must perform a cooling action, to counteract the temperature increase due to the heat generated in the cells for the reasons indicated above. For this purpose, the thermal regulation system comprises an external circuit to the battery module (not illustrated in figure 1), including one or more heat exchangers configured to cool the hot fluid coming from the outlet 6A, before it is fed again, via a pump (not shown), to the inlet 5A. However, under extreme operating cond