Single battery and battery module

Abstract

The battery module comprises a battery body and a coating layer arranged on the outer side of the battery body, the coating layer comprises a first coating layer and a second coating layer, the first coating layer is arranged on the large face of the battery body, the second coating layer is arranged on the side face of the battery body, and the first coating layer is arranged on the large face of the battery body. The first coating layer is an elastic material layer, and the compressible amount of the first coating layer is 10-70%. The large surface of the battery body is provided with the insulating and heat-insulating elastic coating layer with the concave-convex structure on the surface, so that the size consistency of the single battery after the battery module is assembled can be ensured, the expansion space of the single battery is reserved, and the situation that the structure is damaged and the performance is reduced due to the expansion of the single battery is avoided; and meanwhile, the design of the concave-convex structure can ensure that the battery module can be prepared by simple operation during battery grouping.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power batteries, and in particular to a single cell and a battery module. Background Art

[0002] In recent years, new energy vehicles have developed rapidly. As one of the key systems of new energy vehicles, power batteries play an important role in key performance of new energy vehicles such as safety, endurance, and cost.

[0003] The power battery system of new energy vehicles is generally composed of multiple single cells connected in series and parallel. Single cells are generally divided into cylindrical batteries, soft-pack batteries and square-shell batteries according to different packaging forms. In order to ensure the electrical safety of the battery system, single cells generally need to be insulated. Taking square-shell batteries as an example, the outer surface must be coated with an insulating film to improve the insulation performance of the battery and thus improve the system safety of the battery. However, there are also many problems with insulating films in practical applications, such as slow coating speed, affecting production rhythm, and bubbling during battery use. In particular, with the rise of new technologies such as CTP (module-free power battery pack, Cell to Pack) and CTC (battery body integration technology, Cell to Chassis), higher requirements are put forward on how to achieve insulation protection of battery components.

[0004] Secondly, in addition to the need to coat the single cell with an insulating film, insulation protection must also be performed at the module level when the cells are grouped. After the single cells are stacked, an end insulating pad must be installed between the single cell and the fixed end plate, and a side insulating film must be installed between the single cell and the fixed steel belt to ensure the electrical safety of the battery module. The existence of these insulating protection parts not only increases the BOM (Bill of Materials) cost of the battery system, but also increases the manufacturing cost.

[0005] Moreover, single cells will expand during the charge and discharge process. Therefore, when the cells are grouped, a buffer structure needs to be set between the cells. At the same time, in order to suppress the heat transfer to adjacent single cells caused by thermal runaway of a single cell, the single cells also need to be insulated. Generally, this is done by setting a buffer insulation pad. However, the presence of the buffer insulation pad will increase the complexity of the structure and the BOM cost. At the same time, since the buffer insulation pad is generally used to bond the single cells together through double-sided tape, the release paper needs to be removed during assembly for bonding, which seriously restricts the improvement of production efficiency. Summary of the invention

[0006] In order to solve the above technical problems, the present disclosure provides a single cell and a battery module.

[0007] In a first aspect, the present disclosure provides a single battery, comprising a battery body and a coating layer disposed outside the battery body, wherein:

[0008] The coating layer includes a first coating layer and a second coating layer, wherein the first coating layer is arranged on the large surface of the battery body, and the second coating layer is arranged on the side surface of the battery body, and the first coating layer is an elastic material layer with a compressibility of 10-70%.

[0009] As a preferred technical solution of the present disclosure, the thermal conductivity of the first coating layer is less than 0.5 W / m·k.

[0010] As a preferred technical solution of the present disclosure, the thickness of the first coating layer is 3-15% of the thickness of the battery body.

[0011] As a preferred technical solution of the present disclosure, the outer surface of the first coating layer has a concave-convex structure.

[0012] As a preferred technical solution of the present disclosure, the thickness of the second coating layer is ≤ the thickness of the first coating layer, and the thickness of the second coating layer is ≤ 2 mm.

[0013] As a preferred technical solution of the present disclosure, both the first coating layer and the second coating layer are insulating layers.

[0014] The present invention provides an insulating, heat-insulating elastic coating layer with a concave-convex structure on the large surface of the battery body, thereby ensuring the size consistency of the single cells after assembling the battery module, and reserving expansion space for the single cells to ensure that the structure will not be damaged or the performance will not be reduced due to the expansion of the single cells; at the same time, the design of the concave-convex structure can ensure that the battery module can be prepared by simple operation when the batteries are grouped.

[0015] In a second aspect, the present disclosure provides a battery module, comprising at least one single battery as described in the first aspect.

[0016] As a preferred technical solution of the present disclosure, in the battery module, the first coating layers of any two adjacent single cells are contact surfaces.

[0017] As a preferred technical solution of the present disclosure, the battery module further includes a fixed end plate and a fixed steel belt, wherein:

[0018] There are two fixed end plates, which are respectively arranged at two ends of the battery module in the arrangement direction of the plurality of single cells, and the fixed steel belt is wound around the battery module and the two fixed end plates.

[0019] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0020] (1) The present disclosure introduces an elastic material with compressible and resilient properties as the first coating layer on the large surface of the single battery body, which can absorb the size increase caused by the volume expansion of the single battery, thereby ensuring that the battery module composed of the single battery will not be structurally damaged or have performance degradation caused by the volume expansion of the single battery. In addition, the first coating layer with compressible and resilient properties can absorb assembly deviations and ensure the dimensional consistency of the battery module.

[0021] (2) The first coating layer is made of a material with low thermal conductivity, which can prevent the adjacent cells from being affected by thermal diffusion due to abnormalities such as thermal runaway in a single cell;

[0022] (3) The surface of the first coating layer has a concave-convex structure, which can increase the friction between the single cells and facilitate grouping;

[0023] (4) Both the first coating layer and the second coating layer have insulating properties, which can ensure the electrical safety of the single cell and the battery system;

[0024] (5) At the same time, the second coating layer can also play a protective role.

[0025] (6) The use of the single battery provided by the present disclosure to prepare a battery module can simplify the structure of the battery group, reduce the use of parts, and reduce the BOM cost of the battery module;

[0026] (7) The use of the single cells provided in the present disclosure to prepare battery modules can simplify the assembly process of the modules, facilitate automation, improve production efficiency, and make the process controllable, with high product consistency, which can reduce manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 It is a schematic diagram of the structure of the buffer and thermal insulation pad disclosed in the present invention;

[0030] Figure 2 It is a structural schematic diagram of the battery body disclosed in the present invention;

[0031] Figure 3is a schematic structural diagram of a single cell battery disclosed in the present invention;

[0032] Figure 4 A cross-sectional view and a partial enlarged view of the single cell disclosed in the present invention;

[0033] Figure 5 This is a schematic diagram of the explosion structure of a conventional battery module;

[0034] Figure 6 A schematic diagram of the explosion structure of the battery module provided by the present disclosure;

[0035] in:

[0036] 101- cushioning foam; 102- double-sided tape; 103- release paper;

[0037] 11-top surface; 12-left large surface; 13-front side surface; 14-positive pole; 15-liquid injection port; 16-negative pole;

[0038] 1-first coating layer; 2-second coating layer;

[0039] 201 - battery cell; 202 - buffer insulation pad; 203 - end insulation pad; 204 - fixed end plate; 205 - side insulation film; 206 - fixed steel belt; 207 - single battery. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0042] At present, it is generally necessary to coat the single battery with an insulating film. At the same time, when the batteries are grouped into battery modules, it is also necessary to set a buffer insulation pad between adjacent single batteries, such as Figure 1 As shown, the buffer insulation pad includes a buffer foam 101 and double-sided tape 102 arranged on both sides of the buffer foam 101, and a release paper 103 is arranged with the double-sided tape 103 away from both sides of the buffer foam 101; when in use, the release paper needs to be removed, and then the buffer insulation pad is attached to the large surface of the battery cell to achieve the setting of the buffer insulation pad. This method takes a long time and consistency cannot be guaranteed. Therefore, the present disclosure provides a single cell and a battery module to facilitate industrial production and reduce costs.

[0043] In a first aspect, the present disclosure provides a single battery, comprising a battery body and a coating layer disposed outside the battery body, wherein:

[0044] The coating layer includes a first coating layer and a second coating layer, the first coating layer is arranged on the large surface of the battery body, the second coating layer is arranged on the side of the battery body, and the first coating layer is an elastic material layer, which can be compressed by 10-70%, for example, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, etc.

[0045] For the present disclosure, the structural schematic diagram of the battery body is as follows Figure 2 As shown, according to Figure 2 The battery is placed as shown, and the battery body includes:

[0046] Top surface 11;

[0047] a bottom surface (not shown) opposite to the top surface;

[0048] Large surface: including a left large surface 12 and a right large surface opposite to the left large surface (not shown in the figure);

[0049] Side surface: including a front side surface 13 and a rear side surface (not shown in the figure) opposite to the front side surface;

[0050] Positive electrode column 14, liquid injection port 15, negative electrode column 16, etc.

[0051] It should be understood in the art that the large surface in the present disclosure refers to the left large surface and the right large surface, and the present disclosure does not limit the placement of the battery. If the battery is placed "flat", it refers to the upper large surface and the lower large surface.

[0052] The structural schematic diagram of the single cell disclosed in the present invention is as follows Figure 3 As shown, a first coating layer 1 is provided on a large surface of the battery body, and a second coating layer 2 is provided on a side surface of the battery body.

[0053] Since different battery bodies have certain deviations in thickness, when the battery bodies are stacked to form a battery module, the maximum deviation may be several millimeters or even more than ten millimeters. The present invention introduces an elastic first coating layer in the structure. The first coating layer can be compressed and can rebound when the force is removed after compression. The deviation in the assembly process can be improved by the elastic first coating layer, thereby ensuring the dimensional consistency of the battery module.

[0054] At the same time, the single cells in the battery module may swell during charging, discharging and later use, and the general expansion rate is 3-8% of the thickness of the single cell. The present invention introduces a first coating layer with a compressible amount of 10-70%, which can avoid the impact of the size increase caused by the expansion of the single cell on the entire battery module through compression, thereby ensuring that the battery module will not be structurally damaged and the performance will not be reduced due to the expansion of the single cell.

[0055] The compressibility of the first coating layer described in the present disclosure means that the coating layer can be compressed and rebound after compression, and the compressibility is 10-70% of the coating thickness.

[0056] As a preferred technical solution of the present disclosure, the material used for the first coating layer can be any currently available compressible material with low thermal conductivity. The present disclosure does not limit this, but only exemplifies it here: foamed polyurethane can be used, that is, the first coating layer of the present application can be a foamed polyurethane layer.

[0057] As a preferred technical solution of the present disclosure, the first coating layer and the second coating layer completely cover the four surfaces of the battery body except the top surface and the bottom surface, and the surfaces are smoothly transitioned and connected.

[0058] As a preferred technical solution of the present invention, the thermal conductivity of the first coating layer is less than 0.5 W / m·k, for example, 0.45 W / m·k, 0.4 W / m·k, 0.35 W / m·k, 0.3 W / m·k, 0.25 W / m·k, 0.2 W / m·k, 0.15 W / m·k, 0.1 W / m·k, etc.

[0059] The first coating layer provided by the present invention has low thermal conductivity, and its thermal conductivity coefficient is extremely low. When the single cells provided by the present invention form a battery module, any single cell having abnormalities such as thermal runaway can be isolated from heat conduction by the first coating layer, thereby ensuring that adjacent batteries will not be affected by abnormal cells and cause heat diffusion to affect the entire battery module.

[0060] As a preferred technical solution of the present invention, the thickness of the first coating layer is 3-15% of the thickness of the battery body, for example, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, etc.

[0061] When the single cells provided by the present disclosure are grouped into a module and the battery body expands, the first coating layer will be compressed, and the compressed first coating layer will also generate pressure on the battery body, and the generated pressure can suppress the expansion of the battery body.

[0062] At the same time, after the single cells provided by the present disclosure are grouped into modules, the steel belts included in the modules can play a role in tightening and fixing, and can also suppress the expansion of the batteries to a certain extent. Figure 4 It is a cross-sectional view and a partial enlarged view of a single cell. It can be seen from the figure that, as a preferred technical solution of the present disclosure, the outer surface of the first coating layer 1 has a concave-convex structure.

[0063] At present, if two adjacent single cells are in direct contact, not only will there be insulation problems, making it difficult to group the batteries; in addition, since the surface of the single cells is relatively smooth, after the two smooth surfaces come into contact with each other, it is easy to slip, resulting in dimensional deviation in the battery grouping, making it impossible to carry out subsequent processes. However, the present invention can increase the friction between adjacent single cells by providing a concave-convex structure on the surface of the first coating layer. After the two adjacent single cells come into contact with each other, only a very small force is required to make the adjacent single cells fit together without slipping, which can ensure that the battery grouping operation is simpler and greatly reduce the deviation rate.

[0064] As a preferred technical solution of the present invention, the thickness of the second coating layer is ≤ the thickness of the first coating layer, and the thickness of the second coating layer is ≤2 mm, for example, 1.9 mm, 1.8 mm, 1.6 mm, 1.5 mm, 1.4 mm, 1.2 mm, 1.0 mm, 0.8 mm, 0.5 mm, etc.

[0065] As a preferred technical solution of the present disclosure, both the first coating layer and the second coating layer are insulating layers.

[0066] The first coating layer and the second coating layer provided in the present disclosure are both insulating layers, which can replace the blue insulating film in the current prior art, have good insulating properties, and can ensure the electrical safety of single cells and battery modules.

[0067] At the same time, the presence of the second coating layer can not only play an insulating role to improve the safety of the battery module, but also play a protective role, protecting the battery body during the transportation and assembly of the single battery. The introduction of the second coating layer can also eliminate the use of side insulating film when assembling the battery module, further reducing costs.

[0068] As a preferred technical solution of the present disclosure, the material used for the second coating layer can be any currently available material with certain insulation properties. The present disclosure does not limit this, and only exemplifies it here: the second coating layer can be formed by using foamed polyurethane.

[0069] In a second aspect, the present disclosure provides a battery module, comprising at least one single battery as described in the first aspect.

[0070] As a preferred technical solution of the present disclosure, in the battery module, the first coating layers of any two adjacent single cells are contact surfaces.

[0071] The first coating layer of the single cell provided by the present invention has compressible and resilient properties. When the single cells are stacked into groups, a certain force can be applied in the stacking direction, and the first coating layer will be compressed by the force, and the friction between adjacent cells will be greater. Then, a battery module is formed by fixing the end plates and fixing the cable ties.

[0072] When the single cells provided by the present disclosure are used to form a battery module, the battery group structure can be simplified, the use of parts can be reduced by 50%, and the BOM cost of the battery module is greatly reduced.

[0073] Not only that, it can also simplify the battery module assembly process, facilitate automation, improve production efficiency, and reduce the manufacturing cost of the battery module. The process is more controllable and the product consistency is higher.

[0074] As a preferred technical solution of the present disclosure, the battery module further includes a fixed end plate and a fixed steel belt, wherein:

[0075] There are two fixed end plates, which are respectively arranged at two ends of the battery module in the arrangement direction of the plurality of single cells, and the fixed steel belt is wound around the battery module and the two fixed end plates.

[0076] The schematic diagram of the explosion structure of the conventional battery module is as follows Figure 5 ,like Figure 5 As shown, the current conventional battery module generally includes:

[0077] A plurality of battery cells 201 (which are conventional single batteries with blue insulating films in the prior art), and a buffer and heat-insulating pad 202 arranged at intervals between the plurality of battery cells;

[0078] Two end insulating pads 203 are arranged at two ends of the battery module in the arrangement direction of the multiple battery cells 201;

[0079] Two fixed end plates 204 are arranged outside the two end insulating pads 203;

[0080] A fixed steel belt 206 is wound around the battery module and two fixed end plates 204, used to fix the end insulating pads 203, multiple battery cells 201, etc.;

[0081] The side insulating film 205 is disposed on the side surfaces of the plurality of battery cells 201 to provide insulation.

[0082] The exploded structure diagram of the battery module provided in the present disclosure is shown in Figure 6As shown in the figure, the battery module provided by the present disclosure includes:

[0083] A plurality of single cells 207 provided by the present disclosure are arranged in parallel, and the contact surface between two adjacent single cells 207 is the first coating layer;

[0084] Two fixed end plates 204 are disposed at two ends of the battery module in the arrangement direction of the plurality of single batteries 207;

[0085] The fixed steel belt 206 is wound around the battery module and two fixed end plates 204 to fix the end insulating pads 203 and multiple single batteries 207.

[0086] The battery module provided in the present application can omit the use of buffer insulation pads, thereby avoiding the increased production cost and production time caused by setting up insulation buffer pads. It can also omit the use of end insulation pads and side insulation films, thereby reducing the manufacturing cost of the battery module, making the process more controllable and the product consistency higher.

[0087] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0088] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A single cell battery, characterized in that: The invention comprises a battery body and a coating layer arranged outside the battery body, wherein: The coating layer includes a first coating layer and a second coating layer, wherein the first coating layer is arranged on the large surface of the battery body, and the second coating layer is arranged on the side surface of the battery body, and the first coating layer is an elastic material layer with a compressibility of 10-70%.

2. The single cell according to claim 1, characterized in that: The thermal conductivity of the first coating layer is less than 0.5 W / m·k.

3. The single cell according to claim 2, characterized in that: The thickness of the first coating layer is 3-15% of the thickness of the battery body.

4. The single cell according to claim 3, characterized in that: The outer surface of the first coating layer has a concavo-convex structure.

5. The single cell according to claim 1, characterized in that: The thickness of the second coating layer is less than or equal to the thickness of the first coating layer, and the thickness of the second coating layer is less than or equal to 2 mm.

6. The single cell according to any one of claims 1 to 5, characterized in that: The first coating layer and the second coating layer are both insulating layers.

7. A battery module, characterized in that: The method comprises at least one single cell according to any one of claims 1 to 6.

8. The battery module according to claim 7, characterized in that: In the battery module, the first coating layers of any two adjacent single batteries are contact surfaces.

9. The battery module according to claim 8, characterized in that: The battery module further comprises a fixed end plate and a fixed steel belt, wherein: There are two fixed end plates, which are respectively arranged at two ends of the battery module in the arrangement direction of the plurality of single cells, and the fixed steel belt is wound around the battery module and the two fixed end plates.

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