Battery pack

Abstract

The application discloses a battery pack and relates to the technical field of batteries. The battery pack comprises a box body, a cell stack arranged in the box body, a cover plate arranged above the cell stack, the cover plate being provided with first through holes, each soft package cell being arranged in correspondence with at least one first through hole, and a first filling piece arranged between the cover plate and the cell stack. The first through hole is provided with the first filling piece on both sides along a second direction, the projection of the first through hole and the first filling piece do not coincide, and the second direction is perpendicular to a first direction. A weak area not blocked by the first filling piece is formed in the corresponding area of the first through hole, thereby forming a directional pressure relief channel. The heat runaway gas and heat are discharged from the pressure relief channel in a directional manner, and meanwhile, the cover plate itself serves as an isolation structure to prevent high-temperature substances from spreading to adjacent cells, so that the directional pressure relief and heat spread prevention functions of the soft package cell heat runaway are simultaneously realized at the module level.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery pack. Background Technology

[0002] In the field of battery pack technology using pouch cells, thermal runaway safety is a key requirement in the design of the entire vehicle and battery system. Because pouch cells are encapsulated with aluminum-plastic film, their structural characteristics make it difficult to directly integrate explosion-proof valves on the individual cells. Therefore, how to achieve controlled emission of thermal runaway gases and prevent thermal diffusion after assembly has always been an important technical goal in this field.

[0003] In related technologies, when conventional pouch cells experience thermal runaway, the gas generated inside often erupts randomly from relatively weak points such as the cell seal and tabs. The high-temperature gas and accompanying particulate matter can easily directly impact or flow through the areas of adjacent cells. Due to the uncontrollability of this gas emission method, it can easily cause adjacent cells to be rapidly heated, triggering heat spread and thus endangering the safety of the entire battery pack. Summary of the Invention

[0004] To address the aforementioned problems, this application provides a battery pack.

[0005] This application provides a battery pack, including: a housing; a cell stack, formed by stacking multiple pouch cells along a first direction and disposed within the housing; a cover plate disposed above the cell stack, the cover plate having a first through hole, each pouch cell corresponding to at least one first through hole; and a first filler disposed between the cover plate and the cell stack; the first filler is disposed on both sides of the first through hole along a second direction, the first filler extending continuously along the first direction, and in the orthographic projection of the plane formed by the first direction and the second direction, the projection of the first through hole and the first filler do not coincide, the second direction being perpendicular to the first direction.

[0006] Optionally, the length of the pouch cell along the second direction is L, and the dimension of each first through hole along the length direction of the pouch cell is H, satisfying: 0.25≤H / L≤0.4.

[0007] Optionally, multiple first through holes are spaced apart along the first direction, the width of the first through hole along the first direction is a, the thickness of the soft-pack battery cell is b, and 0.5≤a / b≤0.9.

[0008] Optionally, the orthographic projection of the first through hole onto the pouch cell is located in the middle region of the pouch cell along the second direction.

[0009] Optionally, the pouch cell includes a tab disposed at the end of the pouch cell along a second direction, and the cover plate is further provided with a second through hole. The projection along a third direction shows that the second through hole at least partially overlaps with the tab. The battery pack also includes a third filler for covering the tabs, the tabs having upper and lower edges disposed opposite each other in a third direction, the third filler extending in a third direction and covering the upper and lower edges.

[0010] Optionally, the first filler extends continuously along the second direction to the edge region of the second through hole.

[0011] Optionally, a heat insulation element is provided between adjacent pouch cells, the heat insulation element protruding along a third direction from the surface of the pouch cell near the cover plate.

[0012] Optionally, the battery pack further includes a cover located above the cover plate, and the distance between the upper surface of the cover plate and the lower surface of the cover plate is 2mm-16mm.

[0013] Optionally, a fixing beam is provided inside the box on both sides of the cover plate along the second direction, and the two ends of the cover plate are fixedly connected to the fixing beam by fasteners.

[0014] Optionally, the sealing edge of the pouch cell is disposed on the side wall of the pouch cell near the first through hole.

[0015] Optionally, the housing includes a base plate, and a second filler is provided between the battery cell stack and the base plate.

[0016] To address the issues of directional pressure relief and the potential for thermal runaway to spread to adjacent cells when using pouch cells in battery packs, a solution is proposed. This solution involves creating a first through-hole corresponding to the pouch cell on the cover plate, and placing a first filler extending continuously in the first direction on both sides of the first through-hole along a second direction. The projections of the first through-hole and the first filler do not coincide, creating a weak area in the pouch cell corresponding to the first through-hole that is not sealed by the first filler. The gap between the pouch cell and the first through-hole, together with the first through-hole, forms a directional pressure relief channel. When a pouch cell experiences thermal runaway, the internal gas preferentially escapes from this weak area and then through the pressure relief channel. The first filler and the cover plate together isolate adjacent pouch cells, preventing the spread of high-temperature gas and flames. This achieves directional pressure relief and suppresses thermal spread at the module level, effectively improving the safety of the battery pack. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the battery pack according to an embodiment of this application.

[0018] Figure 2 This is a top view of the battery pack in an embodiment of this application without the cover plate, intended to illustrate the structural diagram of the cell stack and the housing.

[0019] Figure 3 This is a partial schematic diagram of the battery pack with the cover removed according to an embodiment of this application.

[0020] Figure 4 This is a schematic diagram illustrating the installation structure of the cover plate and the fixed beam, which is the main embodiment of this application.

[0021] Figure 5 This is a schematic diagram of the cover plate in an embodiment of this application.

[0022] Figure 6 This is an embodiment of the present application. Figure 1 BB section view in the middle.

[0023] Figure 7 This is a schematic diagram of the structure of the soft-pack battery cell according to an embodiment of this application.

[0024] Figure 8 This is a structural schematic diagram of the cover plate from another perspective of an embodiment of this application, mainly showing the adhesive-blocking structure.

[0025] Figure 9 This is a schematic diagram of the structure of the battery cell stack in an embodiment of this application.

[0026] Figure 10 yes Figure 9 Enlarged view of part A in the image.

[0027] Explanation of reference numerals in the attached drawings: 100, battery pack; 110, casing; 111, base plate; 112, casing cover; 113, fixing beam; 120, cell stack; 121, soft-pack cell; 1211, tab; 130, cover plate; 131, first through hole; 132, second through hole; 133, mounting hole; 134, screw; 140, first filler; 150, adhesive barrier structure; 151, first adhesive barrier rib; 152, second adhesive barrier rib; 160, second sealant; 170, heat insulation component; 180, second filler. Detailed Implementation

[0028] In the field of battery pack technology, when conventional pouch cells experience thermal runaway, the gas generated inside often erupts randomly from relatively weak points such as the cell seal and tabs. The high-temperature gas and accompanying particulate matter can easily directly impact or flow through the areas of adjacent cells. Due to its uncontrollability, this gas emission method can easily cause adjacent cells to be rapidly heated, triggering heat spread and thus endangering the safety of the entire battery pack.

[0029] To overcome the aforementioned problems, this invention proposes a different technical approach. Its core concept lies in: a cover plate is placed above the cell stack, with a first through-hole formed on the cover plate. A first filler is placed between the cover plate and the cell stack, with the first filler positioned at both ends of the first through-hole in a second direction perpendicular to the stacking direction. This ensures that the area corresponding to the cell and the first through-hole is not blocked by the filler, thus forming a path for directional discharge from the cell to the through-hole. Simultaneously, the cover plate itself acts as an isolation structure, preventing the discharged high-temperature substances from spreading to surrounding cells. In other words, this invention provides a solution for constructing a directional pressure relief channel and integrating isolation functions at the module level, addressing the technical challenge of simultaneously achieving directional pressure relief from thermal runaway and preventing heat spread in pouch cell stacks. This achieves the effect of directional discharge of thermal runaway gas without affecting adjacent cells.

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0031] [Example Battery Pack] refer to Figures 1 to 5 This application provides a battery pack 100 that can be used in various electrical devices to provide them with power. The battery pack 100 includes a housing 110, a cell stack 120, a cover plate 130, and a first filler 140.

[0032] The housing 110 forms the outer outline of the battery pack 100, and has an overall rectangular structure with internal storage space. The housing 110 can be made of materials such as metal or plastic, and has sufficient structural strength to protect the internal components.

[0033] The cell stack 120 is formed by stacking multiple pouch cells 121 along a first direction and disposed within the receiving space of the housing 110. The pouch cell 121 can be a lithium-ion cell, a sodium-ion cell, or a cell based on other chemical systems, and its outer shell is a flexible encapsulation film, such as an aluminum-plastic film, containing electrode components and electrolyte. Multiple pouch cells 121 are arranged in groups along the thickness direction, and adjacent cells can be tightly fitted or have gaps between them.

[0034] The cover plate 130 is disposed above the cell stack 120. "Above" here means that the cover plate 130 is located on the side of the cell stack 120 away from the bottom of the housing 110. The cover plate 130 can be a plate-shaped component, and the material can include steel plate, aluminum alloy, glass fiber reinforced plastic, or mica composite board. Materials with certain heat resistance and flame retardant properties are preferred to withstand the high-temperature impact of thermal runaway gases. The cover plate 130 can be fixed to the side wall of the housing 110 or the cell stack 120 by bolts, clips, or adhesives.

[0035] The cover plate 130 has a first through hole 131, which is an opening structure that penetrates its upper and lower surfaces. The shape of the first through hole 131 can be rectangular, racetrack-shaped, or elliptical, and its length in the second direction is greater than its width in the first direction, so as to accommodate the length direction of the soft-pack battery cell 121.

[0036] A first filler 140 is disposed between the cover plate 130 and the cell stack 120. The first filler 140 is provided on both sides of the first through hole 131 along the second direction. The first filler 140 extends continuously along the first direction, and in the orthographic projection of the plane formed by the first and second directions, the projections of the first through hole 131 and the first filler 140 do not coincide. The second direction is perpendicular to the first direction. A certain gap exists between the lower surface of the cover plate 130 and the upper surface of the cell stack 120, and the first filler 140 is disposed within this gap. The first filler 140 is used to seal and isolate the space between the upper surface of the cell stack 120 and the lower surface of the cover plate 130. Specifically, the first filler 140 is disposed on the outer regions of both ends of any one of the first through holes 131 along the second direction (i.e., the length direction of the soft-pack cell 121), that is, in regions away from the first through hole 131 along the second direction. The projections of the first through-hole 131 and the first filler 140 do not coincide. In other words, the first filler 140 is not placed in the area directly opposite the first through-hole 131 and the soft-pack battery cell 121, i.e., in the gap between them. This results in the area directly below the first through-hole 131—that is, the space between the upper surface of the battery cell stack 120 and the lower surface of the cover plate 130—forming a channel that is not blocked by the first filler 140 at the position corresponding to the first through-hole 131. This channel starts from the upper surface of the battery cell stack 120, passes through the first through-hole 131, and extends to the space above the cover plate 130.

[0037] It should be noted that the first direction, the second direction, and the third direction are only used to schematically describe the relative orientation between the components and do not constitute an absolute limitation on the actual usage posture of the product. In this application, the first direction, the second direction, and the third direction are perpendicular to each other. The first direction can be understood as the thickness stacking direction of the multiple pouch cells 121, which is also equivalent to the width direction of the housing 110, i.e., the X-axis direction shown in the figure; the second direction can be understood as the extension direction of the pouch cells 121, or the length direction of the housing 110, i.e., the Y-axis direction shown in the figure; and the third direction can be understood as the thickness direction of the housing 110, i.e., the Z-axis direction shown in the figure.

[0038] With the above structure, when thermal runaway or other abnormal situations occur in the cell stack 120, a large amount of high-temperature gas and particulate matter will be generated inside. Because the cover plate 130 is tightly fitted or sealed to the cell stack 120 via the first filler 140 in areas other than the first through-hole 131, high-temperature and high-pressure substances cannot easily break through these areas, nor can they spread extensively along the surface of the cover plate 130 in the second direction to the adjacent pouch cells 121. Thus, the substances generated by the runaway cell are directed to this unblocked channel and discharged through the first through-hole 131 on the cover plate 130. The solid portion of the cover plate 130 acts as an isolation barrier, physically preventing the high-temperature substances discharged from the runaway pouch cell 121 from interfering with other pouch cells 121 from above the cover plate 130, thereby simultaneously achieving the dual functions of directional pressure relief and prevention of thermal spread.

[0039] In some embodiments, see Figure 4 Inside the housing 110, fixing beams 113 are provided on both sides of the cover plate 130 along the second direction, and the fixing beams 113 extend along the first direction. The two ends of the cover plate 130 are fixedly connected to the fixing beams 113 by fasteners, which can be screws 134. Mounting holes 133 are provided at both ends of the cover plate 130 along the second direction, and the screws 134 pass through the mounting holes 133 and are threadedly connected to the fixing beams 113. To increase the connection strength, multiple mounting holes 133 are provided at intervals along the first direction on the cover plate 130. When the soft-pack battery cell 121 experiences thermal runaway, it can easily cause deformation of the entire battery cell stack 120. Installing and fixing the cover plate 130 on the fixing beam 113, rather than directly connecting it to the cell stack 120, can effectively ensure the stability of the cover plate 130 position, prevent the cover plate 130 from shifting as the cell stack 120 deforms, keep the gap between the soft-pack cell 121 and the first through hole 131 and the pressure relief channel formed by the first through hole 131 unobstructed, ensure stable exhaust pressure relief, prevent heat spread, and improve the safety of the battery pack.

[0040] See Figure 6 To ensure the uniqueness and reliability of directional pressure relief and prevent unexpected bottom pressure relief paths, a second filler 180 is provided between the cell stack 120 and the base plate 111 of the housing 110. The base plate 111 is a structural component forming the bottom surface of the housing 110. The second filler 180 is a material that fills the space between the lower surface of the cell stack 120 and the upper surface of the base plate 111 of the housing 110, such as an adhesive similar to the first sealant or a thermally conductive structural adhesive. The second filler 180 completely covers the bottom area of ​​each pouch cell 121, sealing all bottom edge scraps and sealing areas of the cells.

[0041] With this design, when the pouch cell 121 ruptures in other areas due to increased internal pressure, the second filler 180, acting as a robust barrier at the bottom, completely seals off the downward path of high-temperature, high-pressure gas or flame. This forces all matter and energy released from the runaway pouch cell 121, after the downward path is blocked, to be directed towards a predetermined, least-resistance upward channel, such as the directional pressure relief path formed by the unblocked first through-hole 131. This makes the thermal runaway emission behavior more controllable.

[0042] To further optimize the directional pressure relief effect of each pouch cell 121 and provide a more independent and adjacent pressure relief path for each cell, as a supplement to the above scheme.

[0043] The number of first through holes 131 on the cover plate 130 of the battery pack 100 can be set to multiple. See Figure 3 Multiple first through holes 131 are arranged at intervals along a first direction, i.e., the stacking direction of the pouch cells 121. Each pouch cell 121 corresponds one-to-one with at least one first through hole 131. The first direction is perpendicular to the second direction, therefore these first through holes 131 arranged along the first direction together constitute a pressure relief hole array corresponding to the stack below. Each first through hole 131 is separated from the other by the solid structure of the cover plate 130.

[0044] Each first through-hole 131 is an independent opening area, directly corresponding to the side wall of the soft-pack battery cell 121 below it near the cover plate 130. Adjacent soft-pack battery cells 121 correspond to their respective independent first through-holes 131 above them.

[0045] With this structure, when any one of the pouch cells 121 in the stack experiences thermal runaway, the high-temperature, high-pressure gas and particles it generates can enter the directional pressure relief channel formed by the first through-hole 131 directly above via the shortest path. Since each pouch cell 121 is equipped with a dedicated pressure relief hole, namely the first through-hole 131, the pressure relief behavior of each cell is independent, avoiding the risk that when multiple pouch cells 121 share a large pressure relief port, the high-temperature material ejected from one pouch cell 121 will spread laterally and affect adjacent cells.

[0046] In a specific example, the number of first through holes 131 is equal to the number of pouch cells 121, and the position of each pouch cell 121 corresponds one-to-one with each first through hole 131, that is, the pouch cell 121 and the first through hole 131 are directly opposite each other. Each pouch cell 121 has an independently configured dedicated pressure relief channel directly above it. When any pouch cell 121 experiences thermal runaway, the high-temperature and high-pressure gas and particles rise vertically in the vertical direction, resulting in the shortest path, the least resistance, and the pressure relief efficiency reaching the theoretical maximum value.

[0047] In another example, the number of first through-holes 131 is less than the number of pouch cells 121, and there can be one or more first through-holes 131. Reducing the number of through-holes simplifies the process and reduces the risk of leakage.

[0048] In another embodiment, the number of first through holes 131 is greater than the number of pouch cells 121, that is, at least one pouch cell 121 corresponds to multiple first through holes 131, or each pouch cell 121 corresponds to two or more first through holes 131. The larger number of first through holes 131 reduces the width of a single first through hole 131, improving the isolation effect of the cover plate 130, preventing high-temperature substances from flowing back through the first through holes 131 to other pouch cells 121, and avoiding damage to adjacent pouch cells 121.

[0049] For any of the above-mentioned technical solutions that achieve directional pressure relief through the first through hole 131, the degree of matching between the size of the first through hole 131 and the size of the soft-pack battery cell 121 has an impact on both the pressure relief effect and the structural integrity.

[0050] Specifically, see Figure 5 and Figure 7 The length of each pouch cell 121 along the second direction can be defined as L, and the dimension of the first through hole 131 corresponding to the pouch cell 121 along the length direction (i.e., the second direction) of the pouch cell 121 can be defined as H. The two satisfy the relationship: 0.25 ≤ H / L ≤ 0.4. It should be noted that L refers to the length of the main structure of the pouch cell 121, that is, it does not include the length of the tab 1211.

[0051] The ratio H / L represents the proportion of the first through-hole 131 along the length of the cell. H is the span dimension of the first through-hole 131 in the second direction, while L is the overall packaging span of a single pouch cell 121 in the second direction. When this ratio is limited to the range of 0.25 to 0.4, it means that the length of the first through-hole 131 in the second direction cannot be too short or too long.

[0052] If the H / L ratio is too small, i.e., less than 0.25, meaning the size of the first through-hole 131 along the length of the cell is too small, the effective cross-sectional area for pressure relief will be insufficient. This may lead to insufficient and untimely discharge of gas and heat generated by thermal runaway, resulting in excessive internal pressure accumulation and a risk of casing rupture or unexpected breakage. If the H / L ratio is too large, i.e., greater than 0.4, meaning the through-hole size is too large, it will excessively weaken the strength of the solid portion of the cover plate 130 around the first through-hole 131. This makes the cover plate 130 prone to deformation or damage during normal cell use or in the event of thermal runaway. Furthermore, an excessively large opening may allow external foreign objects, such as thermal runaway gas or solid particles, to enter more easily. By controlling the H / L ratio within the range of 0.25 to 0.4, the structural integrity and protective capability of the cover plate 130 can be maintained to the maximum extent while providing sufficient pressure relief area and ensuring unobstructed pressure relief.

[0053] Preferably, the ratio of dimension H to length L can be further controlled between 0.28 and 0.36 to obtain a more balanced overall performance.

[0054] Alternatively, the ratio of dimension H to length L can be selected from one of the following specific values: 0.26, 0.27, 0.29, 0.30, 0.32, 0.33, 0.35, 0.37, 0.38, and 0.39. These values ​​are distributed around or within this preferred range, constituting discrete alternative design schemes, which can provide product engineers with a variety of specific choices in actual development.

[0055] In addition to the dimensional constraints in the second direction, the dimensions of the first through hole 131 in the first direction are also related to the balance between pressure relief performance and structural strength.

[0056] Further, see Figure 3 The width of the first through hole 131 along the first direction can be defined as 'a', and the thickness of a single pouch cell 121 can be defined as 'b'. The two satisfy the relationship: 0.5 ≤ a / b ≤ 0.9.

[0057] Width 'a' is the aperture size of the first through-hole 131 in the first direction perpendicular to the second direction, and thickness 'b' is the packaging thickness of a single pouch cell 121 along the stacking direction. This ratio a / b defines the relative opening of the first through-hole 131 in the cell thickness direction. If a / b is less than 0.5, meaning the width of the through-hole in the stacking direction is too narrow relative to the cell thickness, it will restrict the instantaneous discharge flow of high-temperature gas, causing poor venting. If a / b is greater than 0.9, meaning the through-hole width is almost close to the thickness of the entire cell, the solid connection between two adjacent through-holes in the first direction of the cover plate 130 becomes very weak and may not be able to withstand normal mechanical loads or the impact of thermal runaway, easily breaking at that point. By maintaining a / b in the range of 0.5 to 0.9, the sufficiency of the pressure relief channel in the thickness dimension is ensured, and sufficient support ribs of sufficient width are reserved for the cover plate 130, maintaining the overall structural stability of the module.

[0058] Preferably, the ratio of width a to thickness b can be further selected in the range of 0.6 to 0.8 to achieve better overall performance.

[0059] Alternatively, the ratio of width a to thickness b can be selected from one of the following specific point values: 0.55, 0.58, 0.62, 0.65, 0.68, 0.72, 0.75, 0.78, 0.82, 0.85. These point values ​​provide optional, engineering-meaning dimensional relationships within the design space.

[0060] See Figure 6 To ensure that regardless of where high-pressure gas originates within the pouch cell 121, it can reach the pressure relief port (i.e., the first through-hole 131) via a relatively even and shortest path, the orthographic projection of any first through-hole 131 onto the corresponding pouch cell 121 is configured to be located in the central region of the pouch cell 121. The first through-hole 131, as an opening penetrating the cover plate 130, projects its outline vertically downwards along a direction perpendicular to the upper surface of the pouch cell 121. This vertical direction, also known as the third direction, forms a projection area on the upper surface of the cell. This projection area falls precisely in the middle of the upper surface of the cell, without significantly deviating to either end.

[0061] It can be understood that the central region of the pouch cell 121 is relative to its two ends extending along the second direction. Specifically, the central region can be within 1 / 3 to 2 / 3 of the overall length of the pouch cell 121 along the second direction.

[0062] This design shortens the path of gas flowing from any location to the central pressure relief area as much as possible when thermal runaway occurs inside the cell. It prevents pressure buildup in areas far from a particular end from failing to release in time, thus avoiding excessive localized stress. Therefore, the pressure relief response speed is improved, and the process from the initial gas generation to the directional activation of pressure relief is much faster.

[0063] In order to further improve the directional pressure relief path and make an active discharge design for the tab 1211 area of ​​the pouch cell 121, in the context of the structure in which the tab 1211 of the pouch cell 121 itself is set at its end along the second direction, the cover plate 130 is additionally provided with a second through hole 132 in the area corresponding to these tabs 1211.

[0064] refer to Figure 5 and Figure 6 The tab 1211 of the pouch cell 121 is a metal conductive sheet that extends from inside the cell body for electrical connection, and it is typically located at the end edge of the pouch cell 121 along the second direction. On the cover plate 130, one or more independent second through holes 132 are provided directly opposite the area of ​​the tab 1211. The second through hole 132 is a through opening with a similar function to the first through hole 131, but its location specifically corresponds to the area where the tab 1211 is located.

[0065] By adding a second through-hole 132, more preset pressure relief points exist inside the battery pack 100. In the early stage of thermal runaway, if pressure accumulates in the area near the tab 1211, high-temperature gas can be discharged through the second through-hole 132, increasing the total number of exhaust paths. This allows pressure to be released more quickly from multiple preset channels, avoiding the risk of local pressure accumulation near the tab 1211 when relying solely on the first through-hole 131, which could even lead to unpredictable rupture of the aluminum-plastic film at the tab 1211 or cause a short circuit between the tabs 1211.

[0066] In one specific embodiment, the first filler 140 is a first sealant. In order to ensure that the first sealant does not damage the carefully constructed directional pressure relief channel while performing the sealing and fixing functions, the first sealant is controlled to extend continuously along the second direction, but its extension range terminates exactly at the edge region of the second through hole 132.

[0067] The first sealant is an adhesive or sealing material that cures after application, such as silicone, epoxy, or polyurethane. In the gap between the cover plate 130 and the cell stack 120, the first sealant spreads along the second direction, filling most of the upper surface of the soft-pack cell 121 to provide bonding, fixation, and insulation against lateral heat transfer. However, as the first sealant spreads, its flow front reaches the edge of the second through-hole 132, and through volume control and process settings, it stops flowing inward. Ultimately, the boundary of the first sealant is precisely at the edge of the second through-hole 132, ensuring unobstructed flow in the area directly below it. Similarly, this process control applies to the first through-hole 131, ensuring that the first sealant does not completely cover or intrude into the space directly below it.

[0068] In this way, the first sealant forms a sealed layer on the top of the cell, but precisely avoids the areas where all the first through holes 131 and the second through holes 132 are located. This ensures that when the cell experiences thermal runaway, high-temperature gas can be discharged without obstruction through these unsealed channels, thus reliably realizing the construction of directional pressure relief channels from a manufacturing process perspective.

[0069] In order to more reliably prevent the first sealant from accidentally overflowing into the first through hole 131 or the second through hole 132 due to its fluidity during the process, thereby causing blockage of the pressure relief channel, a sealant-blocking structure 150 is also provided on the cover plate 130.

[0070] refer to Figure 8 The sealant barrier structure 150 is an integrally molded structure protruding downward from the lower surface of the cover plate 130 or an independent component fixed to the lower surface of the cover plate 130. Its function is to act as a physical barrier when the first sealant is applied, blocking the flow front of the sealant and thus preventing the sealant from entering the through hole.

[0071] In this embodiment, the adhesive-blocking structure 150 includes first adhesive-blocking ribs 151. The first adhesive-blocking ribs 151 are constructed on both sides of each first through-hole 131 and each second through-hole 132, and each first adhesive-blocking rib 151 extends along a first direction. These first adhesive-blocking ribs 151, extending continuously along the stacking direction, constitute a longitudinal barrier for the through-holes on both sides in a second direction.

[0072] Furthermore, the adhesive-blocking structure 150 also includes second adhesive-blocking ribs 152. The second adhesive-blocking ribs 152 are constructed between two adjacent first through holes 131 and / or between two adjacent second through holes 132, and each second adhesive-blocking rib 152 extends along a second direction. The second adhesive-blocking ribs 152 constitute lateral barriers at both ends of the through holes in the first direction. The ends of these second adhesive-blocking ribs 152 intersect with the ends of the aforementioned first adhesive-blocking ribs 151, thereby spatially forming a closed annular adhesive-blocking frame that completely and individually surrounds each first through hole 131 and / or second through hole 132.

[0073] First, the annular sealing frame, formed by intersecting sealing ribs with different orientations, achieves 360-degree omnidirectional sealing of each pressure relief through-hole. When the first sealant is applied to the gap between the cover plate 130 and the battery cell, any flow tendency towards the through-hole area is blocked by the annular sealing frame, thus completely blocking the path of sealant seeping into the through-hole from any direction. This provides independent and reliable anti-clogging protection for each pressure relief channel, fundamentally ensuring the manufacturing consistency of the directional pressure relief function. Second, the second sealing rib 152 serves to isolate two adjacent pouch cells 121 in the first direction, making it difficult for thermal runaway gas emitted by a runaway pouch cell 121 to crosstalk along the first direction in the area of ​​the cover plate 130 where the first through-hole 131 is located, thus preventing it from affecting adjacent pouch cells 121.

[0074] In one specific embodiment, see Figure 6 The battery pack 100 also includes a third filler, which may be a second sealant 160. The second sealant 160 is used to cover the tabs 1211, and the second sealant 160 extends in a third direction, namely the thickness direction of the housing 110, with its top protruding above the surface of the tabs 1211 near the cover plate 130. This is to prevent uncontrollable displacement, overlap, or short circuit of the tabs 1211 of the pouch cell 121 during thermal runaway.

[0075] The second sealant 160 is also a curable adhesive or sealant, such as epoxy or UV adhesive. The tab 1211 is a sheet-like metal conductor led out from inside the battery cell. The second sealant 160 encapsulates all or part of the tab 1211 by covering or potting it. Its height along the third direction is higher than the upper surface of the tab 1211 itself, forming a complete encapsulating adhesive layer.

[0076] The structure of the second sealant 160 firstly physically anchors and encapsulates the tab 1211. Even in the event of high-pressure gas impact due to thermal runaway, the tab 1211 will be firmly fixed in place by the cured second sealant 160, preventing it from swinging or bending due to airflow impact, and avoiding contact between adjacent tabs 1211 or between tabs 1211 and components such as the cover plate 130, which could lead to an external short circuit. At the same time, the dense sealant layer itself also forms a barrier, reducing the pressure relief tendency in this area, further ensuring that the main pressure relief occurs accurately at the first through hole 131 and the second through hole 132, improving the reliability of directional pressure relief.

[0077] To further enhance the effect of preventing heat spread, a separate heat insulation element 170 is provided between adjacent pouch cells 121. This heat insulation element 170 protrudes from the surface of the pouch cell 121 in a third direction.

[0078] refer to Figure 9 and Figure 10 The heat insulation component 170 is a sheet-like material with extremely low thermal conductivity, such as foam, aerogel felt, mica board, or ceramic fiber board. The heat insulation component 170 is inserted into the gap between two adjacent pouch cells 121 and is in close contact with the pouch cells 121 on both sides along the first direction. Its height along the third direction is greater than the height of the main body of the pouch cell 121 after the indentation, causing the top edge of the heat insulation component 170 to extend upwards from the gap between the two cells, protruding from the upper surface of the pouch cell 121.

[0079] When a pouch cell 121 experiences thermal runaway, its massive heat attempts to be conducted laterally to adjacent, functioning cells. The thermal insulation element 170, acting as a thermal barrier, effectively blocks this direct heat conduction path, confining the heat to the area of ​​the runaway cell itself. Simultaneously, because the thermal insulation element 170 protrudes upwards, its extended portion prevents high-temperature substances ejected or flowing from the runaway cell from spreading laterally along the lower surface of the cover plate 130 and across the gap to affect adjacent cells, further enhancing the battery pack 100's performance in preventing thermal spread.

[0080] See a specific example. Figure 6 Above the cover plate 130, a box cover 112 is also provided, which is a component that closes the upper end of the box body 110. There is a specific vertical distance between the upper surface of the cover plate 130 and the lower surface of the box cover 112, which is limited to between 2 mm and 16 mm.

[0081] This spacing forms an exhaust chamber between the cover plate 130 and the casing cover 112. If the spacing is too small, less than 2mm, the resulting exhaust space will be too narrow, and the high-speed airflow will be subject to a significant throttling effect, resulting in a sharp increase in pressure loss and preventing rapid and effective diffusion. This could lead to excessive local pressure or even reverse impact on the battery cells. If the spacing is greater than 16mm, it will unnecessarily increase the overall height of the battery pack 100, reducing the volumetric energy density. At the same time, it will make the cross-sectional area of ​​the exhaust channel too large, weakening the guiding and constraining effect on the airflow. This would not be conducive to quickly guiding the high-temperature gas to the exhaust port at the rear end, and it may also weaken the heat radiation protection of the casing cover 112 provided by the cover plate 130. When the spacing is controlled between 2mm and 16mm, the space utilization and directional exhaust function are balanced. This provides sufficient space for the diffusion and deceleration of the airflow, reducing the direct impact on the casing cover 112, while maintaining the compactness of the structure.

[0082] Preferably, the distance between the upper surface of the cover plate 130 and the lower surface of the box cover 112 can be 4mm to 12mm.

[0083] Alternatively, the distance between the upper surface of the cover 130 and the lower surface of the lid 112 can be selected from one of the following specific values: 3mm, 5mm, 7mm, 8mm, 9mm, 10mm, 11mm, 13mm, 14mm, or 15mm. These values ​​provide a variety of options for selecting an appropriate distance in actual product design.

[0084] In order to actively construct a weak point on the body of the pouch cell 121 that is easier to open preferentially, and to make the starting point of pressure relief more certain and controllable, a preferred arrangement is provided herein. The pouch cell 121 has a sealing edge formed by heat sealing, which is specifically disposed on the side wall of the pouch cell 121 near the first through hole 131.

[0085] The edge sealing of the soft-pack battery cell 121 is a sealed edge formed by heat-pressing the aluminum-plastic film outer packaging. Compared with the perforated bearing surface of the battery cell, the edge sealing area, due to the fusion of two thin films, inherently has stress concentration and strength abrupt changes, making it a natural weak point. This edge sealing is located on the upper sidewall of the soft-pack battery cell 121, corresponding to the area where the first through-hole 131 is located on the cover plate 130. When the internal gas pressure of the battery cell increases, this edge sealing area, due to its lowest strength, will be the first to rupture, and this location precisely corresponds to the channel not blocked by the first filler 140. The sealing of the first filler 140 around the area ensures that after rupture, the gas will not escape laterally but can only be discharged upwards through the first through-hole 131. Together, these two factors form a weak combined area with a definite pressure relief direction and stable opening pressure.

[0086] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A battery pack, characterized in that, include: Box; A cell stack is formed by stacking multiple soft-pack cells along a first direction and is disposed inside the housing; A cover plate is disposed above the cell stack, and the cover plate has a first through hole. Each soft-pack cell is disposed corresponding to at least one first through hole. And a first filler, disposed between the cover plate and the cell stack; The first through hole is provided with the first filler on both sides along the second direction. The first filler extends continuously along the first direction. In the orthographic projection of the plane formed by the first direction and the second direction, the projection of the first through hole and the first filler do not coincide. The second direction is perpendicular to the first direction.

2. The battery pack according to claim 1, characterized in that, The length of the pouch cell along the second direction is L, and the dimension of the first through hole along the length direction of the pouch cell is H, satisfying: 0.25≤H / L≤0.

4.

3. The battery pack according to claim 2, characterized in that, Multiple first through holes are spaced apart along the first direction. The width of the first through hole along the first direction is a, and the thickness of the soft-pack battery cell is b, where 0.5 ≤ a / b ≤ 0.

9.

4. The battery pack according to claim 1, characterized in that, The orthographic projection of the first through hole onto the pouch cell is located in the middle region of the pouch cell along the second direction.

5. The battery pack according to claim 1, characterized in that, The pouch cell includes a tab, which is disposed at the end of the pouch cell along a second direction. The cover plate is also provided with a second through hole. The projection along a third direction shows that the second through hole at least partially overlaps with the tab. In the orthographic projection of the plane formed by the first direction and the second direction, the projection of the second through hole does not coincide with the projection of the first filler. The battery pack also includes a third filler for covering the tabs, the tabs having upper and lower edges disposed opposite each other in a third direction, the third filler extending in a third direction and covering the upper and lower edges.

6. The battery pack according to claim 5, characterized in that, The first filler extends continuously along the second direction to the edge region of the second through hole.

7. The battery pack according to claim 1, characterized in that, A heat insulation element is provided between adjacent pouch cells, and the heat insulation element protrudes along a third direction from the surface of the pouch cell near the cover plate.

8. The battery pack according to claim 1, characterized in that, The battery pack also includes a cover located above the cover plate, and the distance between the upper surface of the cover plate and the lower surface of the cover plate is 2mm-16mm.

9. The battery pack according to claim 8, characterized in that, The box body is provided with fixed beams on both sides of the cover plate along the second direction, and the two ends of the cover plate are fixedly connected to the fixed beams by fasteners.

10. The battery pack according to claim 1, characterized in that, The sealing edge of the soft-pack battery cell is located on the side wall of the soft-pack battery cell near the first through hole.

11. The battery pack according to claim 1, characterized in that, The housing includes a base plate, and a second filler is provided between the battery cell stack and the base plate.

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