Secondary battery module

Abstract

A secondary battery module includes: a cell stack including a plurality of unit cells; a first compression pad disposed between adjacent ones of the unit cells; and a pair of end plates facing each other on the outside of the cell stack.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to a secondary battery module. Background Art

[0002] Unlike primary batteries that are designed not to be (re)charged, secondary (or rechargeable) batteries are batteries that are designed to be able to discharge and recharge. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources, as some examples, for driving motors in hybrid vehicles and electric vehicles and for storing electricity (e.g., household and / or utility-scale power storage). Secondary batteries generally include an electrode assembly including a positive electrode and a negative electrode, a housing that accommodates the electrode assembly, and an electrode terminal connected to the electrode assembly.

[0003] Secondary battery cells have the characteristics of expansion and contraction according to the external environment, charging and discharging conditions, etc. In addition, in order to optimize performance and life, appropriate pressure should be applied to the secondary battery cells. However, when a pressure higher than the appropriate pressure is applied to the secondary battery cells, the electrode plates within the secondary battery cells may be broken, which may reduce conductivity, and problems such as stratification and reduced capacity due to lithium plating may occur. In addition, when a pressure lower than the appropriate pressure is applied to the secondary battery cells, the area of ​​the negative electrode may not be charged, or an increase in contact resistance may occur due to lifting (or separation) of the electrode plates.

[0004] Therefore, appropriate pressure should be applied to the secondary battery cell, and the maximum deformation of the secondary battery module should be limited to the allowable displacement range of the can and cover (such as cover plate) of the secondary battery cell. In addition, in order to prevent interference with the secondary battery pack housing or other secondary battery modules due to the deformation of the secondary battery module, the secondary battery module should only be deformed to the extent that the minimum separation distance is maintained within the secondary battery pack.

[0005] The above information disclosed in this Background section is for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute related (or prior) art. Summary of the invention

[0006] Embodiments of the present disclosure provide a secondary battery module in which, when appropriate pressure is applied to a unit cell or the secondary battery module, a maximum deformation (or a maximum deformation amount) due to expansion of the unit cell is limited.

[0007] However, the present disclosure is not limited to the above aspects and features, and those skilled in the art will clearly understand other aspects and features of the present disclosure from the following description of the present disclosure.

[0008] According to an embodiment of the present disclosure, a secondary battery module includes: a cell stack including a plurality of unit cells; a first compression pad disposed between adjacent ones of the unit cells; and a pair of end plates facing each other at an outer side of the cell stack.

[0009] The secondary battery module may further include a second compression pad disposed between each of the pair of end plates and the cell stack.

[0010] The first compression pad may be configured to be compressed by volume expansion due to a change in a state of charge (SOC) of the plurality of unit cells to prevent the pair of end plates from being deformed.

[0011] The first compression pad may be made of an elastic material and may be reversibly deformable.

[0012] Each of the pair of end plates may include: a central plate parallel to a surface of each unit cell; and an outer plate that is bent relative to the central plate at the beginning of life (BOL) of the plurality of unit cells and extends from the central plate in a direction away from the plurality of unit cells.

[0013] Each of the pair of end plates may have a groove formed in a bent portion between the center plate and the outer plates.

[0014] The groove may be in an inner surface of each of the pair of end plates.

[0015] The pair of end plates may be configured to be deformed by volume expansion due to degradation of the plurality of unit cells and to maintain a constant pressure applied to the plurality of unit cells.

[0016] The pair of end plates may be made of metal and configured to be irreversibly deformed by volume expansion due to degradation of the plurality of unit cells.

[0017] The center plate and the outer plate may be parallel to the one surface of each of the plurality of unit cells at the end of life of the plurality of unit cells.

[0018] The cell stack may include a first cell stack and a second cell stack, and the elastic member may be disposed between the first cell stack and the second cell stack.

[0019] The elastic member may be configured to be compressed by volume expansion due to a change in the charge state of the first cell stack and the second cell stack to prevent the pair of end plates from being deformed.

[0020] The elastic member may include a plurality of unit disc springs.

[0021] The plurality of unit disc springs may be arranged in series or in parallel with each other.

[0022] The unit disc springs arranged in series may be arranged in parallel, or the unit disc springs arranged in parallel may be arranged in series.

[0023] The elastic member may further include a variable cylinder passing through a center of each of the plurality of unit disc springs.

[0024] The variable cylinder may be configured to have a maximum compression amount that prevents the unit disc spring from being damaged.

[0025] According to another embodiment of the present disclosure, a secondary battery module includes: a first cell stack and a second cell stack, each including a plurality of unit cells; a pair of end plates facing each other at outer sides of the first cell stack and the second cell stack, respectively; and an elastic member between the first cell stack and the second cell stack.

[0026] The elastic member may include a plurality of unit butterfly disc springs, and an arrangement of the plurality of unit butterfly springs may be determined based on at least one of a type of the plurality of unit cells, a number of the plurality of unit cells, or a maximum allowable deformation amount of the secondary battery module.

[0027] The secondary battery module may further include a pair of plates facing each other at an outer side of the elastic member and supporting the elastic member.

[0028] However, aspects and features of the present disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art from the detailed description below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following drawings attached to this specification illustrate embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe aspects and features of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to the drawings:

[0030] Figure 1 is a perspective view of a secondary battery module according to an embodiment of the present disclosure;

[0031] Figure 2 is a top view of a unit cell of a secondary battery module according to an embodiment of the present disclosure at the beginning of life (BOL);

[0032] Figure 3 It is shown Figure 2 A top view of a cell at end of life (EOL) as shown in FIG.

[0033] Figure 4 shows an end plate having a groove being deformed according to an embodiment of the present disclosure;

[0034] Figure 5 shows the difference in pressure distribution applied to one surface of a unit cell according to the presence or absence of a compression pad;

[0035] Figure 6 is a graph showing that the initial charge capacity decreases as the number of times the secondary battery is charged and discharged increases;

[0036] Figure 7 is a top view of a secondary battery module including an elastic member according to an embodiment of the present disclosure;

[0037] Figure 8 are a side view and a top view of a unit disc spring included in an elastic member according to an embodiment of the present disclosure;

[0038] Fig. 9 shows an example of arrangement of unit disc springs included in the elastic member according to an embodiment of the present disclosure; and

[0039] Fig.10 An example of an elastic member according to an embodiment of the present disclosure is shown, in which the length of the variable cylinder changes as the elastic member is compressed. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Terms or words used in the present specification and claims are not to be narrowly interpreted in a general or dictionary meaning, but should be interpreted as having meanings and concepts consistent with the technical idea of ​​the present disclosure based on the principle that the inventor can be his / her own lexicon compiler to appropriately define the concept of the term so as to describe his / her invention in the best manner.

[0041] The embodiments described in this specification and the configurations shown in the drawings are only some embodiments of the present disclosure and do not represent all embodiments, aspects and features of the present disclosure. Therefore, it should be understood that when submitting this application, there may be various equivalents and modifications that can replace or modify the embodiments described herein.

[0042] It will be understood that when an element or layer is referred to as being "on," "connected to," or "bound to" another element or layer, it may be directly on, directly connected to, or directly bound to the other element or layer, or there may be one or more intervening elements or layers. When an element or layer is referred to as being "directly on," "directly connected to," or "directly bound to" another element or layer, there may be no intervening elements or layers. For example, when a first element is described as being "bound to" or "connected to" a second element, the first element may be directly bound or connected to the second element, or the first element may be indirectly bound or connected to the second element via one or more intervening elements.

[0043] In the accompanying drawings, for the clarity of the illustration, the sizes of various elements, layers, etc. may be exaggerated. The same reference numerals represent the same elements. As used herein, the term "and / or" includes any and all combinations of one or more related enumerated items. In addition, when describing the embodiments of the present disclosure, the use of "may" relates to "one or more embodiments of the present disclosure". Expressions such as "at least one of ..." and "any one of ...", when following a column of elements, modify the entire column of elements without modifying the individual elements of the column. When phrases such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from the group of A, B, and C" are used to specify a column of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms "use", "use ..." and "being used" may be considered to be synonymous with the terms "utilize", "utilize ..." and "being utilized", respectively. As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation, rather than terms of degree, and are intended to account for the inherent variations in measurements or calculations that one of ordinary skill in the art would recognize.

[0044] It will be understood that although the terms first, second, third, etc. can be used here to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, the first element, component, region, layer or part discussed below can be referred to as a second element, component, region, layer or part without departing from the teachings of the example embodiments.

[0045] For ease of description, spatial relational terms such as "under", "below", "below", "above", "on", etc. may be used here to describe the relationship of an element or feature to another element or feature as shown in the figure. It will be understood that in addition to the orientations depicted in the figures, the spatial relational terms are also intended to cover other different orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as being "below" or "below" other elements or features will be oriented to be "above" or "above" the other elements or features. Therefore, the term "below" can cover both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relational descriptors used here should be interpreted accordingly.

[0046] The terms used herein are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular form "a" is also intended to include the plural form, unless the context clearly indicates otherwise. It will be further understood that the terms "include", "includes ...", "includes" and / or "comprising ...", when used in this specification, indicate the existence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups.

[0047] In addition, any numerical range disclosed and / or described herein is intended to include all sub-ranges of the same numerical precision included in the described range. For example, the range of "1.0 to 10.0" is intended to include all sub-ranges between the described minimum value 1.0 and the described maximum value 10.0 (and including the described minimum value 1.0 and the described maximum value 10.0), that is, all sub-ranges with a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit described here is intended to include all lower numerical limits included therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits included therein. Therefore, the applicant reserves the right to modify this specification (including claims) to clearly describe any sub-range included in the scope clearly described here.

[0048] When two compared elements, features, etc. are referred to as "the same" it may mean that they are "substantially the same". Thus, the phrase "substantially the same" may include situations with deviations that are considered low in the art (e.g., 5% or less). In addition, when a parameter is referred to as being uniform in a given area, this may mean that it is uniform with respect to an average value (e.g., having a uniform average value).

[0049] Throughout the specification, unless stated otherwise, each element may be in the singular or in the plural.

[0050] Arranging an arbitrary element “above (or below)” or “on (or below)” another element may mean that the arbitrary element may be set to be in contact with the upper (or lower) surface of the element, and another element may also be inserted between the element and any element set on (or below) the element.

[0051] Further, it will be understood that when a component is referred to as being “linked,” “coupled” or “connected” to another component, the elements may be directly “coupled,” “linked” or “connected” to each other, or another component may be “interposed” between the component and the other component.

[0052] Throughout the specification, when "A and / or B" is stated, it means A, B, or A and B, unless stated otherwise. That is, "and / or" includes any or all combinations of the listed multiple items. When "C to D" is stated, it means C or more and D or less, unless stated otherwise.

[0053] A battery pack according to an embodiment of the present disclosure includes a battery module and a pack housing having an accommodation space in which the battery module is accommodated.

[0054] The battery module may include a plurality of battery cells and a module housing. The battery cells may be housed in a module housing in a stacked form (or a stacked arrangement or configuration). Each battery cell may have a positive electrode terminal and a negative electrode terminal, and may be round, prismatic, or pouch-shaped depending on the shape of the battery. In this specification, a battery cell may also be referred to as a secondary battery, a battery, or a cell.

[0055] In a battery pack, one cell stack may constitute one module instead of a battery module stack. The cell stack may be accommodated in an accommodation space of a pack case, or may be accommodated in an accommodation space partitioned by a frame, a partition wall, or the like.

[0056] The battery cells may generate a large amount of heat during charging / discharging. The generated heat may accumulate in the battery cells, thereby accelerating the degradation of the battery cells. Therefore, the battery pack may further include a cooling member to remove the generated heat, thereby suppressing the degradation of the battery cells. The cooling member may be provided at the bottom of the accommodation space for the battery cells, but is not limited thereto. In some embodiments, the cooling member may be provided at the top or side depending on the battery pack.

[0057] The battery cell may be configured so that the exhaust gas generated inside the battery cell under abnormal operating conditions (also known as thermal runaway or thermal events) is discharged to the outside of the battery cell. The battery pack or battery module may include an exhaust port for exhausting the exhaust gas to prevent or reduce damage to the battery pack or battery module caused by the exhaust gas.

[0058] The battery pack may include a battery and a battery management system (BMS) for managing the battery. The battery management system may include a detection device, a balancing device, and a control device. The battery module may include a plurality of cells connected in series and / or in parallel to each other. The battery modules may be connected in series and / or in parallel to each other.

[0059] The detection device can detect the state of the battery (e.g., voltage, current, temperature, etc.) and can output state information indicating the state of the battery. The detection device can detect the voltage of each cell constituting the battery or the voltage of each battery module. The detection device can detect the current flowing through each battery cell constituting the battery module or battery pack. The detection device can also detect the temperature of the cell and / or module at at least one point of the battery and / or the ambient temperature.

[0060] The balancing device can perform balancing operations of the battery module and / or balancing operations of the monomers constituting the battery module. The control device can receive status information (e.g., voltage, current, temperature, etc.) of the battery module from the detection device. The control device can monitor and calculate the status of the battery module (e.g., voltage, current, temperature, state of charge (SOC), life (state of health (SOH)), etc.) based on the status information received from the detection device. In addition, based on the monitored status information, the control device can perform control functions (e.g., temperature control, balancing control, charge / discharge control, etc.) and protection functions (e.g., over-discharge, over-charging, over-current protection, short circuit, fire extinguishing function, etc.). In addition, the control device can communicate via a wired or wireless connection with an external device of the battery pack (e.g., a higher-level controller or vehicle, a charger, a power conversion system, etc.).

[0061] The control device can control the charging / discharging operation and the protection operation of the battery. To this end, the control device can include a charging / discharging control unit, a balancing control unit and / or a protection unit.

[0062] A battery management system is a system that monitors the battery status and performs diagnostic and control, communication, and protection functions, and can calculate the charge / discharge status, calculate the battery life or state of health (SOH), cut off the battery power when necessary (e.g., relay control), control thermal management (e.g., cooling, heating, etc.), perform high-voltage interlock functions, and / or can detect and / or calculate insulation and short circuit conditions.

[0063] The relay may be a mechanical contactor that is switched on and off by the magnetic force of a coil or a semiconductor switch such as a metal oxide semiconductor field effect transistor (MOSFET).

[0064] The relay control may have the function of cutting off the power supply to the battery in the event of a problem in the vehicle and battery system (or when a problem occurs in the vehicle and battery system), and may include one or more relays and a pre-charge relay at the positive terminal and the negative terminal, respectively.

[0065] In pre-charge control, when the battery load is connected, there is a risk of inrush current in the high-voltage capacitor on the inverter input side. Therefore, in order to prevent inrush current when starting the vehicle, the pre-charge relay can be operated before the main relay is connected, and the pre-charge resistor can be connected.

[0066] The high-voltage interlock is a circuit that uses a small signal to detect whether all high-voltage parts of the entire vehicle system are connected, and it can also have the function of forcibly disconnecting the relay if a disconnection (cut-off) occurs at even one position along the entire circuit (or when a disconnection (cut-off) occurs at even one position along the entire circuit).

[0067] In the present disclosure, the beginning of life (BOL) of a secondary battery may mean the initial state of the life cycle of the secondary battery. At the beginning of the life of the life cycle, the secondary battery may generally be at an optimal performance level and capacity. The end of life (EOL) of a secondary battery may mean a state where the life cycle of the secondary battery ends and may no longer provide the desired level of performance or capacity. For example, the end of life of a secondary battery may refer to a point in time when the performance of a secondary battery cell is degraded to the point where it is no longer suitable for its original purpose.

[0068] The swelling of a secondary battery cell may mean that the size of the secondary battery cell physically expands due to internal chemical reactions or other factors. The degree of swelling of a secondary battery cell may change throughout the life cycle of the secondary battery cell, including the initial state and the termination state. In addition, in the initial state of the life cycle of the secondary battery cell, the secondary battery cell may not swell or may only swell minimally. In this case, the internal components and materials of the secondary battery cell may not be damaged and are tightly packed. As the secondary battery cell undergoes charge and discharge cycles and ages over time, the secondary battery cell may gradually swell and swell. The swelling phenomenon may be caused by several factors (such as chemical reactions, side reactions, and changes in the secondary battery electrode or electrolyte structure). As the life of the secondary battery cell approaches the termination state, the degree of swelling / swelling of the secondary battery may further increase. Specifically, as the internal degradation process and irreversible changes in the secondary battery cell accumulate, the swelling may increase. The swelling of the secondary battery cell may affect the performance, safety, and overall function of the secondary battery cell. In addition, excessive expansion may lead to increased pressure, mechanical stress, and damage to the secondary battery. Therefore, in order to ensure safe and efficient operation of secondary batteries, it is important to reduce or control the swelling of secondary battery cells.

[0069] Reference Figure 1 , a battery module 100 according to one or more embodiments of the present disclosure includes a plurality of battery cells 10 arranged in one direction, each of the battery cells including terminal portions 11 and 12, a connection tab 20 connecting the cell 10a to an adjacent cell 10b, and a protection circuit module 30 having one end connected to the connection tab 20. The protection circuit module 30 may include a battery management system (BMS). In addition, the connection tab 20 may include a main body portion contacting the terminal portions 11 and 12 of the adjacent cells 10a and 10b and an extension portion extending from the main body portion and connected to the protection circuit module 30. The connection tab 20 may be, for example, a bus bar.

[0070] Each unit cell 10 may include a battery case, an electrode assembly received (contained) in the battery case, and an electrolyte. The electrode assembly and the electrolyte electrochemically react to store and release (e.g., generate) energy. Terminal portions 11 and 12 electrically connected to the connecting tab 20 and an exhaust port 13 serving as an exhaust passage for the gas generated inside the battery case may be provided on one side (e.g., the upper side) of the unit cell 10. The terminal portions 11 and 12 of the unit cell 10 may be a positive electrode terminal 11 and a negative electrode terminal 12 having different polarities from each other, and the terminal portions 11 and 12 of adjacent unit cells 10a and 10b may be electrically connected to each other in series or in parallel via the connecting tab 20, which will be described in more detail below. Although a series connection has been described as an example, the connection structure is not limited thereto, and various connection structures may be adopted as needed or when necessary. In addition, the number and arrangement of the unit cells are not limited to Figure 1 The structure shown can be changed as needed or necessary.

[0071] In addition, the number and arrangement of unit cells are not limited to Figure 1 The structure shown in the figure may be changed as needed or when necessary. For example, the secondary battery module 100 may include one or more single-cell stacks including a plurality of unit cells, and the one or more single-cell stacks may be separated from each other.

[0072] The unit cells 10 may be arranged in one direction (e.g., may be stacked in one direction) so that the wide surfaces of the unit cells 10 face each other, and the unit cells 10 may be fixed by the cases 61, 62, 63, and 64. The cases 61, 62, 63, and 64 may include a pair of end plates 61 and 62 facing the wide surfaces of the unit cells 10 and arranged to face each other on the outside of the unit cells (or one or more cell stacks), and a pair of side plates 63 (in the case of the case 61) connecting the pair of end plates 61 and 62 to each other. Figure 1 The pair of end plates 61 and 62, the pair of side plates 63, and the bottom plate 64 may be connected by bolt connection, welding, and / or any other suitable fastening members and methods known to those of ordinary skill in the art.

[0073] In one or more embodiments, the first compression pad 65 may be arranged between the unit cells 10. Additionally or alternatively, the second compression pad 66 may be provided between each of the pair of end plates 61 and 62 and the unit cell 10. The compression pads 65 and 66 may both be made of an elastic material and may be reversibly deformed. In addition, the compression pads 65 and 66 may both include a flame retardant material and / or a cooling material.

[0074] End plates 61 and 62 may both be made of metal (such as stainless steel or aluminum), carbon fiber material, polymer, or reinforced plastic.

[0075] In one or more embodiments, the end plates 61 and 62 may include central plates 61a and 62a, respectively, and outer plates 61b and 62b, the central plates 61a and 62a being arranged parallel to one surface (e.g., a wide surface) of the unit cell 10, and the outer plates 61b and 62b being bent relative to the central plates 61a and 62a at the beginning of life (BOL) of the unit cell 10 and extending from the central plates 61a and 62a in a direction away from the unit cell 10. Therefore, when the unit cell 10 is deformed due to volume expansion caused by, for example, deterioration, the end plates 61 and 62 may consistently maintain the pressure applied to the unit cell 10, and may increase robustness by limiting the maximum deformation amount within a certain range when swelling occurs at a high level. Figure 2 and Figure 3 The process of deformation of the end plates 61 and 62 is described in detail.

[0076] The protection circuit module 30 may have electronic components and protection circuits mounted thereon, and may be electrically connected to the connection tab 20, which will be described in detail later. The protection circuit module 30 includes a first protection circuit module 30a and a second protection circuit module 30b extending in a direction, wherein the unit cells 10 are arranged at different positions in the direction. The first protection circuit module 30a and the second protection circuit module 30b may be spaced apart from each other at a suitable spacing (e.g., a predetermined spacing), and arranged in parallel with each other to be electrically connected to adjacent connection tabs 20, respectively. For example, the first protection circuit module 30a extends along one side of the upper portion of the unit cell 10 along the direction in which the unit cells 10 are arranged, and the second protection circuit module 30b extends along the other side of the upper portion of the unit cell 10 along the direction in which the unit cells 10 are arranged. The second protection circuit module 30b may be spaced apart from the first protection circuit module 30a at a suitable spacing (e.g., a predetermined spacing) with the exhaust port 13 interposed therebetween, and may be arranged in parallel to the first protection circuit module 30a. As such, the two protection circuit modules 30a and 30b are spaced apart from each other and arranged side by side in a direction perpendicular to the direction in which the unit cells 10 are arranged, thereby reducing or minimizing the area of ​​a printed circuit board (PCB) constituting the protection circuit module 30. By separately configuring the protection circuit module 30 into two protection circuit modules 30a and 30b, unnecessary PCB area is reduced or minimized. In addition, the first protection circuit module 30a and the second protection circuit module 30b can be connected to each other by a conductive connecting member 50. One side of the conductive connecting member 50 is connected to the first protection circuit module 30a, and the other side thereof is connected to the second protection circuit module 30b, so that the two protection circuit modules 30a and 30b can be electrically connected to each other.

[0077] The connection may be made by welding, resistance welding, laser welding, projection welding, and / or any other suitable connection method known to those of ordinary skill in the art.

[0078] In addition, the connecting member 50 may be, for example, an electric wire. In addition, the connecting member 50 may be made of a material having elasticity or flexibility. Via the connecting member 50, it is possible to check and manage whether the voltage, temperature and / or current of the unit cell 10 are normal. For example, information (such as voltage, current and / or temperature) received by the first protection circuit module 30a from the connecting tab 20 adjacent to the first protection circuit module 30a and information (such as voltage, current and / or temperature) received from the connecting tab 20 adjacent to the second protection circuit module 30b can be integrated and managed by the protection circuit module 30 through the connecting member 50.

[0079] Furthermore, when the unit cell 10 expands, impact or pressure may be absorbed by the elasticity or flexibility of the connection member 50 , thereby preventing the first and second protection circuit modules 30 a and 30 b from being damaged.

[0080] In addition, the shape and structure of the connecting member 50 are not limited to Figure 1 The shape and structure shown.

[0081] As described above, since the protection circuit module 30 is provided as a first protection circuit module 30a and a second protection circuit module 30b, the area of ​​the PCB constituting the protection circuit module is reduced or minimized, and the space inside the battery module can be improved (or guaranteed), which improves work efficiency by facilitating the fastening between the connecting terminal 20 and the protection circuit module 30 and the maintenance work in the event that an abnormality is detected in the battery module 100 (when an abnormality is detected in the battery module 100).

[0082] Figure 2 2 is a top view of a secondary battery module 200 including a unit cell 210 at the beginning of life (BOL) according to an embodiment of the present disclosure. The secondary battery module 200 may include one or more single stacks including a plurality of unit cells 210, one or more first compression pads 220 arranged between the unit cells 210, and a pair of end plates 240 and 250 arranged to face each other at the outside of the one or more single stacks.

[0083] In one or more embodiments, the first compression pad 220 may be compressed by volume expansion caused by a change in the state of charge (SOC) of the unit cell 210, and thus, the end plates 240 and 250 may be prevented from being deformed. For example, in a state where the unit cell 210 is fully charged (SOC 100%), the volume of the unit cell 210 may expand compared to when the unit cell 210 is fully discharged (SOC 0%). In this case, the first compression pad 220 may be compressed by the volume expansion of the unit cell 210.

[0084] In one or more embodiments, the second compression pad 230 may be disposed between each of the pair of end plates 240 and 250 and the one or more cell stacks. Thus, the pressure applied by the end plates 240 and 250 may be uniformly transferred to one surface (eg, outer surface) of each unit cell 210.

[0085] The first compression pad 220 and the second compression pad 230 may both be made of an elastic material and may be reversibly deformed. For example, the first compression pad 220 and the second compression pad 230 may both be made of a material such as polyurethane, but are not limited thereto.

[0086] The pair of end plates 240 and 250 may include center plates 240a and 250a arranged parallel to one surface (e.g., wide surface) of each unit cell 210, and outer plates 240b and 250b bent relative to the center plates 240a and 250a at the beginning of life (BOL) of the unit cell 210 and extending from the center plates 240a and 250a in a direction away from the unit cell 210. In one or more embodiments, a groove may be formed in a bent portion between the center plates 240a and 250a and the outer plates 240b and 250b. In this case, the grooves may be formed in inner surfaces (e.g., surfaces facing the unit cells 210) of the end plates 240 and 250, respectively.

[0087] In one or more embodiments, the bending angle between the outer plates 240b and 250b and the corresponding central plates 240a and 250a may vary depending on the type of the unit cell 210 (e.g., an all-solid-state secondary battery or a lithium-ion secondary battery), the maximum deformation of the secondary battery module 200, the pressure applied to the unit cell 210, and the like. For example, the unit cell 210 included in the secondary battery module 200 may be formed to absorb a relatively high swelling pressure by having a larger bending angle when the unit cell 210 generates a higher swelling pressure. The thickness of the end plates 240 and 250 may also be determined according to the maximum deformation of the secondary battery module 200, the pressure applied to the unit cell 210, and the like.

[0088] Not limited to Figure 2, the end plates 240 and 250 may have various structures to increase robustness, thereby limiting the maximum deformation amount within a certain range when the swelling force caused by expansion occurs at a high level at the end of life (EOL) of the unit cell. For example, the end plates 240 and 250 may both be formed to have an arch or dome shape, or may further include a plate extending from the outer plates 240b and 250b.

[0089] Figure 3 is a top view showing a secondary battery module 300 including a unit cell 310 at the end of life (EOL) according to one or more embodiments of the present disclosure. Figure 2 A description given of the secondary battery unit cell 310 , the first compression pad 320 , and the second compression pad 330 is omitted below due to redundancy.

[0090] The end plates 340 and 350 may be configured to maintain a constant pressure applied to the plurality of unit cells 310 deformed by volume expansion caused by degradation of the unit cells 310. The pair of end plates 340 and 350 may be made of metal and may be plastic deformation plates. Therefore, the pair of end plates 340 and 350 may be irreversibly deformed by volume expansion caused by degradation of the unit cells 310.

[0091] At the end of life (EOL) of the unit cell 310, the swelling force due to the expansion of the unit cell 310 may occur at a high level. In response to this, at the end of life of the unit cell 310, the center plates 340a and 350a and the outer plates 340b and 350b can be deformed to be parallel to one surface of each unit cell 310, so that appropriate pressure can be continuously applied to the unit cell 310 while limiting the maximum deformation amount of the secondary battery module 300. With this configuration, the end plates 340 and 350 can provide a constant pressure from the beginning of the life of the secondary battery module 300 to the end of its life.

[0092] At the end of the life of the unit cell 310, the compression pads 320 and 330 may be compressed by volume expansion due to a change in the charge state of the unit cell 310 and may absorb pressure applied to the end plates 340 and 350, thereby preventing the end plates 340 and 350 from being deformed.

[0093] Figure 4An example of deformation of an end plate 410 having a groove 412 therein according to one or more embodiments of the present disclosure is shown. The end plate 410 may include a center plate 240a disposed parallel to one side of each of a plurality of unit cells and an outer plate 240b bent relative to the center plate 240a and extending in a direction away from the center plate 240a. The end plate 410 has a groove 412 formed in a bent portion between the center plate 240a and the outer plate 240b so that the end plate 410 responds to volume expansion due to degradation of the unit cells (e.g., in Figure 4 In this case, the groove 412 may be formed in the inner surface of the end plate 410. The end plate 410 may represent a state of the end plate at the beginning of life (BOL) of the unit cell.

[0094] Since the groove 412 is formed in the end plate 410, the end plate 420 is deformed in response to the expansion caused by the degradation of the unit cell to be parallel to one side of each unit cell. For example, according to the expansion caused by the degradation of the unit cell, the center plate 240a can move (e.g., deform or bend) parallel to the expansion direction of the unit cell, and the outer plate 240b connected to the center plate 240a can move parallel to one side of each unit cell. The deformed end plate 420 can represent the state of the end plate at the end of life (EOL) of the unit cell.

[0095] Alternatively, the end plate 410 may be deformed by forming a hinge in a bent portion between the center plate 240a and the outer plate 240b.

[0096] Figure 5 The difference in distribution of pressure applied to one surface of the unit cell according to the presence or absence of the compression pad is shown. The first heat map 510 shows the distribution of pressure applied to one surface of the unit cell when the compression pad is not provided between the end plate and the unit cell and between the unit cells. The second heat map 520 shows the distribution of pressure applied to one surface of the unit cell when the compression pad is provided between the end plate and the unit cell and between the unit cells.

[0097] like Figure 5 As shown, in the first heat map 510, a lower pressure is applied to the outer edge of the unit cell, while a higher pressure is applied to the inner area of ​​the unit cell. That is, as can be seen in the first heat map 510, the pressure is not uniformly applied to the unit cell. In addition, it can be seen in the second heat map 520 that by using the compression pad, the pressure is more uniformly applied to one surface of the unit cell. That is, by providing the compression pad between the end plate and the unit cell and between the unit cells, the pressure can be uniformly applied to one surface of the unit cell.

[0098] Figure 6600, which shows that the initial charge amount decreases as the number of times the secondary battery is charged and discharged increases. It can be seen from the graph 600 that the degradation of the secondary battery progresses the slowest when only one cell (single cell) is used. In addition, it can be seen that in a state where the secondary battery module includes a plurality of secondary battery cells (15S1P module), due to the expansion of the secondary battery, the degradation of the secondary battery progresses faster than when only one cell (single cell) is used.

[0099] In addition, in the state where the compression pad (1.68T or 3.6T) and the end plate according to the present disclosure are applied to a secondary battery module including a plurality of secondary battery cells (DF-JIG (1.68T) and DF-JIG (3.6T)), it can be seen that the life of the secondary battery module is greatly increased compared to the secondary battery module (15S1P module), where T can represent the thickness, for example, can be 1 mm. In addition, it can be seen that in the state where the thickness of the compression pad is increased from 1.68T (DF-JIG (1.68T)) to 3.6T (DF-JIG (3.6T)), the life of the secondary battery module is further increased. That is, it can be seen that as the compression thickness of the compression pad increases, the life of the secondary battery increases.

[0100] Figure 7 2 is a top view of a secondary battery module 700 in which an elastic member 750 is provided according to one or more embodiments of the present disclosure. Descriptions of the end plates 730 and 740 that are the same as those given previously are omitted.

[0101] The elastic member 750 may be disposed between the first single cell stack 710 including a plurality of unit cells and the second single cell stack 720 including a plurality of unit cells. The elastic member 750 may be compressed by volume expansion due to a change in the charge state of the first single cell stack 710 and the second single cell stack 720, and thus, the end plates 730 and 740 may be prevented from being deformed, and a free space required for contraction and expansion of the unit cells or the first single cell stack 710 and the second single cell stack 720 may be obtained. In addition, when the volume of the unit cells is greatly expanded due to a change in the charge state, the elastic member 750 may absorb the pressure due to the expansion.

[0102] In one or more embodiments, the elastic member 750 may include a plurality of unit disc springs 752. Figure 8 The detailed structure of the unit disc spring 752 is described.

[0103] In one or more embodiments, the unit disc springs 752 may be arranged in series or in parallel. The unit disc springs 752 arranged in series may be arranged in parallel, or the unit disc springs 752 arranged in parallel may be arranged in series to form the elastic member 750. Therefore, the elastic force and / or compression length of the elastic member 750 may be adjusted. This will be described below with reference to Fig. 9 Detailed description.

[0104] In one or more embodiments, the elastic member 750 may include variable cylinders 754 and 756 passing through the center of the unit disc spring 752. When the unit disc spring 752 is compressed, the variable cylinders 754 and 756 may be compressed together. For example, the lengths of the variable cylinders 754 and 756 may be reduced by inserting a protrusion 758 formed on one side of the second variable cylinder member 756 into the hollow portion of the first variable cylinder member 754. This will be described below with reference to Fig.10 Detailed description.

[0105] In addition, a pair of plates facing each other may be further disposed at the outer side of the elastic member 750. The pair of plates facing each other may support the elastic member 750 from the outside (eg, from the outer edge or side).

[0106] Additionally or alternatively, the elastic member 750 may be disposed between the first end plate 730 and the first cell stack 710 and / or between the second end plate 740 and the second cell stack 720 .

[0107] Although Figure 7 The unit disc spring 752 and the variable cylinders 754 and 756 are shown to be used together, but the present disclosure is not limited thereto. For example, the unit disc spring 752 or only the variable cylinders 754 and 756 may be used.

[0108] Figure 8 1 shows a side view and a top view showing a unit disc spring 800 included in an elastic member according to one or more embodiments of the present disclosure. The lower portion of the unit disc spring 800 may have a first diameter d0. In addition, the hollow portion 820 formed in the upper portion of the unit disc spring 800 may have a second diameter d0 that is smaller than the first diameter d0. i When the unit disc spring 800 is compressed, the inclined portion 810 may be located on the same plane as the hollow portion 820 .

[0109] The variable height h of the unit disc spring 800, the inclination of the inclined portion 810 and / or the thickness t of the unit disc spring 800 may be changed based on the required performance of the elastic member disposed between the unit stacks. For example, as the variable height h increases, the elastic force of the elastic member increases.

[0110] Compared with an embodiment using a coil spring or the like, by using the unit disc spring 800 in the elastic member, the elastic force of the elastic member can be increased relative to the same volume.

[0111] Fig. 9 Examples of first, second and third arrangements 910, 920 and 930 of unit disc springs included in an elastic member according to one or more embodiments of the present disclosure are shown. The first arrangement 910 represents a structure in which a plurality of unit disc springs are arranged in parallel. In this case, compared with an embodiment in which one unit disc spring is used, the maximum compression distances are equal to each other, but the elastic force required for compression can be increased in proportion to the number of unit disc springs used.

[0112] The second arrangement 920 represents a structure in which a plurality of unit disc springs are arranged in series. In this embodiment, compared with the embodiment in which one unit disc spring is included, the maximum compression distance increases in proportion to the number of unit disc springs, but the elastic forces required for compression can be equal to each other.

[0113] The third arrangement 930 represents a structure in which the unit disc springs arranged in series are arranged in parallel or the unit disc springs arranged in parallel are arranged in series. In this embodiment, compared with the embodiment in which one unit disc spring is included, the maximum compression distance is increased in proportion to the number of the unit disc springs arranged in series, and the elastic force required for compression is increased in proportion to the number of the unit disc springs arranged in parallel.

[0114] The arrangement of the unit disc springs can be changed based on the desired performance of the elastic member including the unit disc springs. For example, the arrangement of the unit disc springs can be designed based on at least one of the type of unit cells (e.g., all-solid-state secondary batteries or lithium-ion secondary batteries), the number of unit cells, the maximum allowable deformation of the secondary battery module, the pressure applied to the unit cells, etc. For example, the pressure applied to the unit cells is expected to be different for each type of unit cells, and the pressure applied by the elastic member can be adjusted by the arrangement of the disc springs so that the corresponding pressure can be applied to the unit cells.

[0115] Fig.10An example is shown in which the lengths of the variable cylinders 1014 and 1016 vary as the elastic member 1010 is compressed according to one or more embodiments of the present disclosure. The variable cylinders 1014 and 1016 passing through the center of the plurality of unit disc springs 1012 may include a first variable cylinder member 1014 and a second variable cylinder member 1016, and the second variable cylinder member 1016 may have a protrusion 1018. In the uncompressed elastic member 1010, the protrusion 1018 provided on one side of the second variable cylinder member 1016 may be outside the hollow portion in the first variable cylinder member 1014 or only partially in the hollow portion, and the lengths of the variable cylinders 1014 and 1016 may increase.

[0116] In the compressed elastic member 1030, the protrusion 1018 provided on one side of the second variable cylinder member 1016 can be inserted into the hollow portion of the first variable cylinder member 1014, and the lengths of the variable cylinders 1014 and 1016 can be reduced. Therefore, the variable cylinders 1014 and 1016 can fix the position of the unit disc spring 1012, and the elastic member 1030 can be compressed by an external force.

[0117] In one or more embodiments, the maximum compression amount of the variable cylinders 1014 and 1016 can be determined to prevent damage to the unit disc spring 1012. For example, the length of the protrusion 1018 (e.g., the maximum compression amount of the variable cylinders 1014 and 1016) can be less than the critical length at which the unit disc spring 1012 may be damaged.

[0118] In contrast, the unit disc spring may include an elastic member arranged on its two surfaces, and may include a pair of facing plates and a cylinder member, wherein a hollow portion is formed in one of the plates, and at least a portion of a cylinder member can be inserted into the hollow portion in the plate, so that the length of the elastic member can be adjusted.

[0119] Although the present disclosure has been described with reference to the embodiments of the present disclosure and the accompanying drawings showing various aspects thereof, the present disclosure is not limited thereto. A person skilled in the art to which the present disclosure belongs may make various modifications and changes within the scope of the technical spirit of the present disclosure and claims and their equivalents.

Claims

1. A secondary battery module, comprising: A single cell stack, including multiple unit cells; a first compression pad disposed between adjacent unit cells in the unit cells; as well as A pair of end plates face each other at the outer sides of the cell stack. 2 . The secondary battery module according to claim 1 , further comprising a second compression pad disposed between each of the pair of end plates and the cell stack.

3. The secondary battery module according to claim 1, wherein: The first compression pad is configured to be compressed by volume expansion due to a change in a state of charge of the plurality of unit cells to prevent the pair of end plates from being deformed.

4. The secondary battery module according to claim 1, wherein: The first compression pad is made of an elastic material and is reversibly deformable.

5. The secondary battery module according to claim 1, wherein: Each of the pair of end plates comprises: a center plate parallel to one surface of each of the unit cells; and The outer plate is bent relative to the central plate at an early stage of the life of the plurality of unit cells and extends from the central plate in a direction away from the plurality of unit cells.

6. The secondary battery module according to claim 5, wherein: Each of the pair of end plates has a groove formed in a bent portion between the center plate and the outer plates.

7. The secondary battery module according to claim 6, wherein: The groove is formed in an inner surface of each of the pair of end plates.

8. The secondary battery module according to claim 5, wherein: The pair of end plates is configured to be deformed by volume expansion due to degradation of the plurality of unit cells and to maintain a constant pressure applied to the plurality of unit cells.

9. The secondary battery module according to claim 8, wherein: The pair of end plates are made of metal, and are configured to be irreversibly deformed by volume expansion due to degradation of the plurality of unit cells.

10. The secondary battery module according to claim 5, wherein: The center plate and the outer plate are parallel to the one surface of each of the plurality of unit cells at the end of life of the plurality of unit cells.

11. The secondary battery module according to claim 1, wherein: The cell stack includes a first cell stack and a second cell stack, and Wherein, the elastic member is arranged between the first unit stack and the second unit stack.

12. The secondary battery module according to claim 11, wherein: The elastic member is configured to be compressed by volume expansion due to a change in the charge state of the first cell stack and the second cell stack to prevent the pair of end plates from being deformed.

13. The secondary battery module according to claim 11, wherein: The elastic member includes a plurality of unit disc springs.

14. The secondary battery module according to claim 13, wherein: The plurality of unit disc springs are arranged in series or in parallel with each other.

15. The secondary battery module according to claim 13, wherein: The unit disc springs arranged in series are arranged in parallel, or the unit disc springs arranged in parallel are arranged in series.

16. The secondary battery module according to claim 13, wherein: The elastic member further includes a variable cylinder passing through a center of each of the plurality of unit disc springs.

17. The secondary battery module according to claim 16, wherein: The variable cylinder is configured to have a maximum compression amount that prevents the unit disc spring from being damaged.

18. A secondary battery module, comprising: A first cell stack and a second cell stack, each comprising a plurality of unit cells; a pair of end plates facing each other at outer sides of the first monomer stack and the second monomer stack, respectively; as well as An elastic member is between the first unit stack and the second unit stack.

19. The secondary battery module according to claim 18, wherein: The elastic member includes a plurality of unit disc springs, and The arrangement of the plurality of unit disc springs is determined based on at least one of the types of the plurality of unit cells, the number of the plurality of unit cells, or the maximum allowable deformation amount of the secondary battery module. 20 . The secondary battery module according to claim 18 , further comprising a pair of plates facing each other at an outer side of the elastic member and supporting the elastic member.

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