US-12627016-B2 - Battery module

US12627016B2US 12627016 B2US12627016 B2US 12627016B2US-12627016-B2

Abstract

A battery module includes a cell stack including a plurality of a battery cell, a module case at least partially accommodating the cell stack, and a cooling unit disposed at one side of the cell stack. The battery cell includes a cell case, an electrode assembly and an electrolyte accommodated in the cell case, and an electrolyte storage unit inserted into the cell case to supply a supplementary electrolyte. The electrolyte storage unit is disposed between the electrode assembly and the cooling unit in a cross-sectional view.

Inventors

Chang Mook Hwang
Kyung Tae Park
Kyeong Min Lee

Assignees

SK ON CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20221214
Priority Date: 20211215

Claims (17)

1 . A battery module, comprising: a cell stack including a plurality of a battery cell; a module case at least partially accommodating the cell stack; and a cooling unit disposed at one side of the cell stack, wherein the battery cell comprises: a cell case; an electrode assembly and an electrolyte accommodated in the cell case; and an electrolyte storage unit inserted into the cell case to supply a supplementary electrolyte, the electrolyte storage unit being disposed between the electrode assembly and the cooling unit in a cross-sectional view, wherein the electrolyte storage unit comprises: a first unit including a first body and first holes formed through the first body, the first body having an outer shape of a polygonal column and a tubular hollow structure; and a sub-unit comprising a tubular body and sub-holes formed through the tubular body, wherein the sub-unit is inserted into the first unit so that the sub-holes are offset from the first holes.
2 . The battery module according to claim 1 , wherein an outer surface of the electrolyte storage unit facing the cooling unit has a flat surface.
3 . The battery module according to claim 2 , wherein the flat surface of the electrolyte storage unit and a bottom surface of the cell case are in a surface-contact, and the bottom surface of the cell case and a top surface of the cooling unit are in a surface-contact in the cross-sectional view.
4 . The battery module according to claim 3 , wherein the bottom surface of the cell case is a non-sealing surface.
5 . The battery module according to claim 1 , wherein the electrolyte storage unit has a polygonal column shape.
6 . The battery module according to claim 1 , wherein a longitudinal direction of the electrode assembly and a longitudinal direction of the electrolyte storage unit are parallel.
7 . The battery module according to claim 1 , wherein the sub-unit comprises a first sub-unit and a second sub-unit which are inserted into both end portions of the first unit.
8 . The battery module according to claim 7 , wherein the first sub-unit and the second sub-unit are disposed in the first unit to be spaced apart from each other in a longitudinal direction of the first unit.
9 . The battery module according to claim 8 , wherein the first sub-unit and the second sub-unit are movable by an external force in the longitudinal direction so that at least one of the sub-holes overlaps at least one of the first holes.
10 . The battery module according to claim 8 , wherein the electrolyte storage unit further comprises: a first packing unit coupled to one end portion of the first sub-unit; and a second packing unit coupled to one end portion of the second sub-unit.
11 . The battery module according to claim 1 , wherein the electrolyte storage unit further comprises a second unit that comprises a second body having a tubular structure and second holes formed through the second body, and the second unit is inserted between the first unit and the sub-unit so that at least one of the second holes overlaps at least one of the first holes.
12 . The battery module according to claim 11 , wherein the second holes are arranged to be offset from the sub-holes.
13 . The battery module according to claim 11 , wherein an inner surface of the first body and an outer surface of the second body have screw structures to be fastened to each other.
14 . The battery module according to claim 11 , wherein the first unit has a first coefficient of thermal expansion, and the second unit has a second coefficient of thermal expansion different from the first coefficient of thermal expansion.
15 . The battery module according to claim 11 , wherein the first unit has a first coefficient of thermal expansion, and the second unit has a second coefficient of thermal expansion different from the first coefficient of thermal expansion, wherein the second unit is physically separable from the first unit at a temperature of −20° C. or less, or 40° C. or higher.
16 . The battery module according to claim 1 , wherein the cell case comprises: a first space accommodating the electrode assembly and the electrolyte; a second space into which the electrolyte storage unit is inserted; and a passage portion through which the supplementary electrolyte is capable of being transferred between the first space and the second space.
17 . The battery module according to claim 16 , wherein the passage portion comprises a sealing line portion that is capable of being opened by a pressure due to a discharge of the supplementary electrolyte.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Korean Patent Application No. 10-2021-0179641 filed on Dec. 15, 2021 in the Korean Intellectual Property Office (KIPO), the entire disclosure of which is incorporated by reference herein. BACKGROUND 1. Field The present invention relates to a battery module. More particularly, the present invention relates to a battery module including a plurality of battery cells. 2. Description of the Related Art A secondary battery which can be charged and discharged repeatedly includes, e.g., a lithium secondary battery, a nickel-cadmium battery, a nickel-hydrogen battery, etc. The lithium secondary battery is highlighted due to high operational voltage and energy density per unit weight, a high charging rate, a compact dimension, etc. For example, a low-capacity lithium secondary battery may be used as a power source for a small electronic device such as a cellular phone, a laptop computer, a camcorder, etc. A high-capacity lithium secondary battery may be used as a power source for a large electronic device such as an electric vehicle, a hybrid vehicle, etc. For example, the lithium secondary battery may include an electrode assembly including repeatedly stacked cathodes and anodes, and an electrolyte immersing the electrode assembly. The lithium secondary battery may further include a case (e.g., a pouch-type cell case) for accommodating the electrode assembly and the electrolyte. The lithium secondary battery may be defined as a battery cell, and a battery module may be formed by accommodating a plurality of the battery cells in a case (module case). For example, the battery cell may be charged and discharged through an electrochemical reaction of the cathode, the anode, and the electrolyte. When the lithium secondary battery is repeatedly charged and discharged, the electrolyte may be transformed due to a side reaction, and an amount of the electrolyte in the battery cell may be gradually reduced. Accordingly, a capacity retention of the battery cell may also be gradually decreased, thereby reducing a life-span of the battery module. For example, Korean Published Patent Application No. 10-2011-0132856 discloses a method of replenishing an electrolyte in a lithium secondary battery. SUMMARY According to an aspect of the present invention, there is provided a battery cell having improved operational stability and life-span. A battery module includes a cell stack including a plurality of a battery cell, a module case at least partially accommodating the cell stack, and a cooling unit disposed at one side of the cell stack. The battery cell includes a cell case, an electrode assembly and an electrolyte accommodated in the cell case, and an electrolyte storage unit inserted into the cell case to supply a supplementary electrolyte. The electrolyte storage unit is disposed between the electrode assembly and the cooling unit in a cross-sectional view. In some embodiments, an outer surface of the electrolyte storage unit facing the cooling unit may have a flat surface. In some embodiments, the flat surface of the electrolyte storage unit and a bottom surface of the cell case are in a surface-contact, and the bottom surface of the cell case and a top surface of the cooling unit are in a surface-contact in the cross-sectional view. In some embodiments, the bottom surface of the cell case may be a non-sealing surface. In some embodiments, the electrolyte storage unit may have a polygonal column shape. In some embodiments, a longitudinal direction of the electrode assembly and a longitudinal direction of the electrolyte storage unit may be parallel. In some embodiments, the electrolyte storage unit may include a first unit including a first body and first holes formed through the first body, the first body having an outer shape of a polygonal column and a tubular hollow structure, and a sub-unit including a tubular body and sub-holes formed through the tubular body. The sub-unit may be inserted into the first unit so that the sub-holes may be offset from the first holes. In some embodiments, the sub-unit may include a first sub-unit and a second sub-unit which are inserted into both end portions of the first unit. In some embodiments, the first sub-unit and the second sub-unit may be disposed in the first unit to be spaced apart from each other in a longitudinal direction of the first unit. In some embodiments, the first sub-unit and the second sub-unit may be movable by an external force in the longitudinal direction so that at least one of the sub-holes may overlap at least one of the first holes. In some embodiments, the electrolyte storage unit may further include a first packing unit coupled to one end portion of the first sub-unit, and a second packing unit coupled to one end portion of the second sub-unit. In some embodiments, the electrolyte storage unit further includes a second unit that includes a second body having a tubular structure and sec