Force measuring module for measuring a force and method for determining a force

Abstract

The invention relates to a force measuring module (100) for measuring the force when a battery module (113) is installed in a battery housing, comprising a housing having substantially the outer dimensions of the battery module (113) and at least one force sensor (104) which is arranged in the housing and is designed to measure the force when the housing is installed in the battery housing. The invention also relates to a method for determining the force when a battery module (113) is installed in a battery housing.

Description

Technical Field

[0001] The invention relates to a force-measuring module for measuring at least one force when a battery module is installed in a battery housing. The invention also relates to a method for determining at least one force when a battery module is installed in a battery housing. Background Art

[0002] When installing a battery module in a battery housing of a battery, the battery module is placed and installed in the battery frame. Then, the battery housing is closed, mostly by screwing or welding the top cover. The battery module includes a connection structure of multiple individual battery cells. During battery operation, heat occurs in the battery cells that must be dissipated, especially via the battery housing. For this reason, a thermal conductive paste is applied to the battery frame before the battery module is installed in the battery housing, and the thermal conductive paste ensures or enhances the thermal conductivity between the battery module and the battery housing. Then, the battery module is pressed onto the battery frame, where the paste-like thermal conductive paste is squeezed out in this part, and then the battery module is screwed together with the battery frame. During installation, a large installation force occurs during the pressing and screwing of the battery module, which can currently be measured by a pressure measuring film, such as Fuji Film according to US 6,742,472 B1, where only the total force during the pressing or screwing of the battery module can be measured with a pressure measuring film. In order to evaluate the measured forces, the user must remove the battery module from the battery housing again and evaluate the intensity of the staining on a separate pressure measuring film, where the staining would correspond to the respective total force during the pressing and screwing of the battery module. It is therefore not possible to measure the force curve over time during the pressing or screwing of the battery module using the pressure measuring film. The battery module is then placed back into the battery housing and screwed on based on the total force determined using the pressure measuring film, so that the internal stresses of the battery cells of the battery module and the internal stresses of the battery frame are minimized, thus ensuring a long service life of the battery module.

[0003] Thus, DE 10 2019 101 403 describes a method for measuring at least one section of a battery module and a section of a battery housing by determining the size and shape of a gap that is present in a specified installation position of the battery module. Subsequently, the mass of a heat conductor is determined based on the determined size and shape of the gap and then introduced into the battery housing. This ensures that an optimal mass of heat conductor is present when the battery module is inserted into the battery housing and thus reduces the forces when pressing and screwing the battery module into the battery housing.

[0004] Since conventional methods for evaluating the total forces during the pressing and screwing of the battery module onto the cell frame of the battery housing are already extremely time-consuming within the scope of the production process, the forces during the final screwing of the cover onto the battery housing have not previously been considered. Summary of the invention

[0005] The object of the present invention is therefore to demonstrate an improved force measurement during the process of installing a battery module in a battery housing using means that are structurally as simple as possible.

[0006] This object is achieved by the subject matter of the independent claims. Advantageous developments of the invention are described in the dependent claims, the description and the drawings.

[0007] One aspect of the present invention relates to a force measuring module for measuring the force when a battery module is installed in a battery housing, having a housing and at least one force sensor, the housing substantially having the shape and outer dimensions of the battery module, the force sensor being arranged in the housing and being set up to measure the force when the housing is installed in the battery housing. When the housing is installed in the battery housing, the force measuring module is pressed into the battery compartment of the battery housing, for example. The force thus generated is measured by the force sensor. For example, the force curve over time during the pressing can also be measured by the force sensor. The force measuring module according to the present patent application is used as a substitute for the battery module actually to be installed during the first pressing and screwing process, so that the force generated, especially its curve over time, can be measured more accurately than the common method with the aid of a force sensor. The force measuring module can then be easily removed from the battery housing again and the measured force can be easily read and used within the scope of the production process. According to this method, the use of a pressure measuring membrane is no longer required. After the force measuring module has been removed, the corresponding battery module can be inserted into a battery housing and finally pressed and screwed, taking into account the forces measured by the force measuring module, wherein internal stresses occurring in the battery cells in the respective battery module and in the battery housing are minimized.

[0008] The force measuring module comprises a top cover, a central part and a bottom surface. In addition, the force measuring module comprises a measuring amplifier. The measuring amplifier can be connected to a data processing unit via a wireless interface and allows a higher force sensor measurement accuracy, thereby making it possible to better analyze the values ​​measured by the force sensor. For example, the measuring amplifier can be placed on the central part of the force measuring module. The central part can also include a rocker switch for switching the force measuring module on and off, a replaceable battery for supplying electrical energy, and a heat exchanger for dissipating heat from the force measuring module. The top cover protects the force measuring module from damage and dirt. The force measuring module is preferably designed as a self-sufficient system with its own power supply and its own measuring system, so that continuous use of the force measuring module within the scope of the production process can be achieved.

[0009] Since the shape and outer dimensions of each battery module fluctuate within a certain error limit, it is also proposed to measure the shape and outer dimensions of the respective battery module to be installed, and to adapt the shape and outer dimensions of the force-measuring module housing to the shape and outer dimensions of the respective battery module to be installed. For this purpose, preferably rails are provided in the bottom, top cover and / or side walls of the force-measuring module, which rails can be connected to corresponding supports and fixing mechanisms at the side walls, in the bottom and / or in the top cover of the force-measuring module, thereby achieving adaptation to different shapes and outer dimensions of the force-measuring module housing in a flexible manner. Here, the adjustment of the shape and outer dimensions of the housing can be accomplished manually by an operator by locking the supports on the respective rails or by means of an electric control device via a servomotor.

[0010] This ensures that the forces and force changes measured by the force measuring module actually and very accurately correspond to the forces and force changes during the subsequent pressing or screwing of the corresponding battery module in the battery housing or during the screwing of the cover on the battery housing. Since the forces and force changes to be expected during pressing and screwing are precisely known, the pressing and screwing forces of the corresponding battery module can be precisely predetermined and applied. By using the pressing and screwing forces that are exactly required when installing the battery module, the internal stresses in the battery module and in the battery housing are minimized, so that the service life of the battery is extended.

[0011] A plurality of force sensors are arranged on the housing or in the force-measuring module in order to be able to measure the force at a plurality of locations. In order to obtain precise measured values, the arrangement of the force sensors can be selected such that the force-measuring module is statically determinate. The resulting force can then be calculated via the center of gravity of the force-measuring module. In order to avoid measuring errors, the force sensors can be arranged, for example, in the form of a triangle that covers as much as possible.

[0012] Alternatively, the force sensor can be arranged at a force-sensitive point in the force-measuring module. For example, it is provided that the force sensor is arranged on the opposite side of the force-measuring module housing with respect to the screw dome or the screw channel into which the screw is screwed. Concentrated stresses are formed around the screw dome or the screw channel during screwing, which are transmitted to the battery module or the battery housing and generate internal stresses. It is also provided within the scope of the present patent application that the force sensor is arranged in the region of the force-measuring module in which the maximum internal stresses are expected during pressing and screwing.

[0013] The force measuring module further comprises at least one heat exchanger, such as a ventilator, which dissipates the heat generated during operation from the force measuring module. This also ensures that the temperature of the force measuring module does not influence the measurement of the force sensor and can be adjusted to the temperature during the pressing and screwing of the battery module, so that during the measurement with the force measuring module, no additional temperature-induced forces occur compared to the pressing and screwing of the corresponding battery module.

[0014] In addition, the force sensor can be arranged in a bottom surface and can be placed in the battery housing. A plurality of force sensors can also be arranged in the bottom surface. The force sensor can be arranged on the bottom surface by means of a shoulder screw. The force sensor can be fixed on the center of the force measuring module. In addition, the force sensor can have a hardened surface. When measuring the force, the weight of the force sensor and / or the force measuring module during the measurement is not taken into account, so that only the forces and force changes that actually occur due to the pressing and / or screwing are measured.

[0015] According to a preferred embodiment, the force measuring module comprises at least two force sensors which are arranged in a spatially dispersed manner in the housing and are each designed to measure the force when the housing is inserted into the battery housing. By arranging a plurality of force sensors on the housing, the force can be measured at a plurality of locations. By means of a subsequent evaluation, the force and the force distribution can be evaluated in relation to the respective position of the force sensors or in relation to a certain area of ​​the force measuring module by means of a mathematical function, for example by averaging the forces at three points with respect to the area between the three points.

[0016] In order to achieve plane parallelism between the bottom surface and the center part, the bottom surface and the center part can be plane milled again after the force measuring module is assembled. The material of the contact surface of the sensor contacting the center part can be wear-free stainless steel. The surface for screwing the force measuring module can also consist of wear-free stainless steel. For example, the top cover of the force measuring module can be made of aluminum. In order to keep the weight of the force measuring module as light as possible, the steel can have notches.

[0017] The housing also has a structure that is configured to thread the force measuring module to the battery housing and / or the top cover, wherein the at least one force sensor is configured to measure the force acting on the force measuring module when the force measuring module is threadedly connected to the battery housing and / or the top cover.

[0018] According to another preferred embodiment, the force measuring module comprises a data processing device, which is set up for collecting and evaluating the force sensor signal of the at least one force sensor. The data processing device can be connected to the measuring amplifier via a data network, such as Ethernet. The force sensor signal can be recorded and evaluated by the data processing device in real time. The data processing device can also record and evaluate the curve of the force change over time when the force measuring module is pressed or screwed.

[0019] In addition, the force measuring module includes a wireless interface, in particular a WLAN interface, which is set up to transmit data from the force measuring module to another data processing device. For example, the other data processing device can be an external computer used by the user. The wireless interface can be placed in the center of the force measuring module. The signal-transmitting plastic cover protects the wireless interface from damage and dirt. Through the wireless interface, the force measuring module can be comfortably operated by the user. It is also possible to send the measurement data of the force measuring module to the external threaded terminal via the wireless interface, based on which the screw parameters can be automatically pre-set for the corresponding battery module and then used during the semi-automatic or automatic pressing and screwing process.

[0020] According to another preferred embodiment, the force measuring module comprises a tank with an energy accumulator, which is set up to supply electrical energy to the force measuring module. For example, the energy accumulator can be a replaceable battery. The battery can supply the force measuring module with a voltage of preferably 12 volts. In addition, the force measuring module can be driven, for example, by a power supply unit. A heat exchanger can be arranged side by side next to the replaceable battery. By means of a warning signal, such as a warning light or a warning display, the user can find out whether the battery needs to be replaced. Therefore, it can be avoided that the force measuring module interrupts the measurement due to insufficient power supply.

[0021] Another aspect of the present invention relates to a method for determining the force when a battery module is installed into a battery housing, comprising: providing a force measuring module with a shell and at least one force sensor, the shell substantially having the outer dimensions of the battery module, the force sensor being disposed in the shell and being configured to measure the force when the shell is installed into the battery housing; installing the force measuring module into the battery housing instead of the battery module; and measuring the force during installation by the force sensor.

[0022] For example, the force-measuring module can be inserted into the battery compartment of the battery housing by means of workpiece clamping jaws. Before the force-measuring module is inserted, a heat-conducting medium such as a caulking agent can be applied into the battery compartment. The force-measuring module can then be pressed into the battery compartment.

[0023] In a preferred embodiment, the shape and outer dimensions of the respective battery modules to be installed are measured, and the shape and outer dimensions of the housing of the force measuring module are adapted to the shape and outer dimensions of the respective battery modules to be installed. For this purpose, the bottom, the top cover and / or the side walls of the force measuring module are preferably moved and locked relative to each other in such a way that flexible adaptation to different shapes and outer dimensions of the housing of the force measuring module is allowed. The adjustment of the housing shape and outer dimensions can be accomplished manually by an operator by locking the supports on the respective rails or by means of a servomotor with the aid of an electrical control device.

[0024] For example, the force measuring module can have three force sensors which are arranged spatially dispersed in the base and measure the forces when the force measuring module is pressed. The measured values ​​can then be recorded and analyzed by a data processing device. After the force measurement, the force measuring module can be removed from the battery compartment by means of the workpiece clamping jaws and a battery module can be inserted into the battery compartment.

[0025] In addition, the forces are measured when the installed force-measuring module is screwed onto the battery housing and / or cover. Based on the forces and force changes determined in the force-measuring module, the battery module can be screwed on by means of workpiece clamping jaws or screw terminals.

[0026] In addition to the measurement and evaluation of the pressing and screwing forces, the degree of wetting of the heat-conducting medium in the battery cell during the pressing and screwing of the force-measuring module can also be analyzed.

[0027] According to a preferred embodiment, the installed force-measuring module is removed and the battery module is installed in the battery housing taking into account the previously measured forces acting on the installed force-measuring module. The battery module can be installed using workpiece clamping jaws.

[0028] Further features, advantages and details of the invention are obtained from the following description of preferred embodiments and in conjunction with the figures. The features and feature combinations mentioned above in the description and the features and feature combinations shown individually in the following description of the figures and / or in the figures can be used not only in the indicated combination, but also in other combinations or individually without exceeding the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is explained in detail below in conjunction with embodiments and drawings, which show:

[0030] Figure 1 shows an exploded view of a force measuring module according to a first embodiment,

[0031] Figure 2 shows a perspective view of a force-measuring module according to a first embodiment,

[0032] Figure 3 shows a perspective view of a force measuring module together with a battery compartment according to a first embodiment,

[0033] Figure 4 shows a sectional view of the bottom surface with the force sensor and the central part according to the second embodiment during pressing of the force-measuring module,

[0034] Figure 5 A schematic diagram of a method for determining the forces when installing a battery module into a battery housing is shown.

[0035] These figures are only schematic and serve only to explain the invention. Identical or functionally identical components are always provided with the same reference numerals.

[0036] Reference numerals list

[0037] 100 Force measurement module

[0038] 101 Bottom

[0039] 102 Center

[0040] 103 Top cover

[0041] 104 Force Sensor

[0042] 105 Battery

[0043] 106 Heat exchange unit

[0044] 107 Wireless Interface

[0045] 108 On-off rocker switch

[0046] 110 Measuring amplifier

[0047] 111 Data processing device

[0048] 112 Warning display

[0049] 113 Battery Module

[0050] 114 Battery compartment

[0051] 115 Sealant

[0052] 116 Mounting tab

[0053] 117 Shoulder screw

[0054] 118 Screws

[0055] 119 Cover

[0056] 120 Force Flow DETAILED DESCRIPTION

[0057] Figure 1 A force-measuring module according to a first exemplary embodiment is shown in an exploded view.

[0058] The force-measuring module 100 comprises a bottom surface 101. According to a first embodiment, the bottom surface is connected to a central part 102 via three force sensors 104. The three force sensors 104 are arranged in a triangular shape on the bottom surface 101 and are fixed on the central part 102. When evaluating the forces and force changes measured on the force sensors 104, the spatial stress distribution can be calculated based on the averaging of the corresponding forces and force changes in a manner related to the positions of these force sensors 104 and in a manner related to the areas between them. In another embodiment, more than three force sensors 104 are arranged on the bottom surface 101 in a manner that differs from one another in spatial distribution, wherein completely different spatial distributions are conceivable, which allow corresponding evaluation methods at the positions of the force sensors 104.

[0059] A replaceable battery 105 is arranged on the central part 102, which supplies electrical energy to the force measuring module 100. When to replace the battery 105 is displayed by a warning display 112 also arranged on the central part 102. Two fans as heat exchange units 106 are also arranged and fixed on the central part 102. In another embodiment, more than two fans 106 are fixed on the central part 102. The fans 106 protect the force measuring module 100 from overheating and conduct away the heat generated during operation, or keep the temperature of the force measuring module 100 at a predetermined temperature, preferably corresponding to the battery module 113 ( Figure 1 (not shown) temperature during pressing and tightening.

[0060] In addition, an on-off seesaw switch 108 and a wireless interface 107 are provided on the central part 102. The on-off seesaw switch 108 is used to switch the force measuring module 100 on and off, preferably when the force measuring module 100 is automatically loaded into the battery housing. According to a first embodiment, the wireless interface 107 is a WLAN interface. Via the wireless interface 107, the force measuring module can communicate with an external data processing device.

[0061] In addition, another data processing device 111 is installed in the central part 102 and is connected to the measuring amplifier 110 via a data network. The data processing device 111 records the measured values ​​respectively measured by the force sensor 104 in real time, analyzes it and calculates the resultant force and / or force change. The mass and the internal stress occurring during the pressing and tightening of the force measuring module 100 are explained based on the calculated force and / or force change. The measuring amplifier 110 is also arranged on the central part 102. The measuring amplifier 110 is used to improve the measuring accuracy of the force sensor 104.

[0062] The force-measuring module 100 further comprises a cover 103 , which protects the force-measuring module 100 from damage and dirt.

[0063] Figure 2 A force-measuring module according to a first exemplary embodiment is shown in a perspective view.

[0064] The bottom surface 101, the center portion 102 and the top cover 103 of the force measuring module 100 are fixed by screws. The housing of the force measuring module 100 corresponds to the shape and outer dimensions of the battery module 113 to be installed.

[0065] Figure 3 The force-measuring module and the battery compartment 114 according to the first exemplary embodiment are shown in a perspective view.

[0066] The bottom surface 101 of the force measuring module 100 is mounted floatingly in the battery compartment 114, because a sealant 115 is applied to the battery compartment 114 before the force measuring module 100 is pressed in. In the example shown, the sealant 115 is added to the bottom of the battery compartment 114 in the form of a strip. The battery compartment 114 comprises a plurality of mounting lugs 116. The force measuring module 100 is screwed onto the battery housing by means of the mounting lugs 116. In this case, the force measuring modules 100 can be individually inserted and screwed into the corresponding battery compartment 114, so that the corresponding battery module 113 is then pressed and tightened while taking into account the forces and force changes measured in the force measuring module 100. This ensures that the internal stresses in the corresponding battery modules 113 of the respective battery compartment 114 are minimized. Alternatively, it is provided that in a first step all battery cells 114 of the battery housing are respectively mounted and screwed with force measuring modules 100, and then the force measuring modules 100 are individually removed from the battery cells 114 and replaced by corresponding battery modules 113, wherein the respective battery modules 113 are pressed and screwed based on the measured force and / or force change of the force measuring module 100 assigned to the respective battery cell 114. The advantage of this approach is that the internal stress of the entire battery housing, rather than only with respect to each battery cell 114, is minimized.

[0067] Figure 4 A sectional view of the bottom surface with the force sensor and the center piece during pressing down of the force-measuring module according to the second exemplary embodiment is shown.

[0068] The force sensor 104 is fixed to the center part 102 by means of screws 118. According to the second embodiment, the bottom surface 101 includes a cover plate 119. In addition, the force sensor 104 is fixed to the bottom surface 101 by means of shoulder screws 117. In the case of shoulder screws 117, only the tip of the screw neck is provided with threads. The rest of the screw neck has a smooth surface, whereby the shoulder screw 117 can move linearly in the threaded hole. The bottom surface 101 is connected to the center part 102 only by means of the shoulder screws 117 and the force sensor 104. When the force measuring module 100 is pressed, the shoulder screws 117 are pressed into the threaded hole. Also in Figure 4 , a force flow 120 is shown in line form when the force-measuring module 100 is pressed. The force is transmitted via the screw 118 and the force sensor 104 .

[0069] Figure 5A schematic diagram of a method for determining the forces when installing a battery module into a battery housing is shown.

[0070] In a first step ( S1 ), a force-measuring module 100 having a housing is provided. The force-measuring module 100 has the shape and outer dimensions of the battery module 113 or is adapted to the shape and outer dimensions of the respective battery module to be installed.

[0071] In the second step ( S2 ), a sealant 115 is applied to the bottom surface of the battery cell 114 .

[0072] In a third step (S3), the force-measuring module 100 is installed in the battery compartment 114 of the battery housing. The force-measuring module 100 is installed in the battery compartment 114 by means of workpiece clamping jaws.

[0073] In the fourth step (S4), the force and / or force change when the force measuring module 100 is installed in the battery cell 114 is measured by the force sensor 104. The force measuring module 100 is subjected to pressure when it is installed in the battery cell 114. According to this embodiment, three force sensors 104 are arranged on the bottom surface 101 of the force measuring module 100. These forces and / or force changes of the respective force sensors 104 are measured. The data processing device 111 records the measured values ​​in real time and calculates the resultant force when the force measuring module 100 is pressed into the battery cell 114.

[0074] In the fifth step (S5), the force when the force measuring module 100 is screwed onto the battery housing and the battery housing top cover is measured by the force sensor 104. In another embodiment, the force when the force measuring module 100 is screwed onto the battery housing or the battery housing top cover can be measured.

[0075] In a sixth step (S6), the force measuring module 100 is removed from the battery compartment 114 by means of a workpiece clamping jaw, and the battery module 113 is subsequently inserted into the battery housing. The previously measured values ​​of the force sensor 104 of the force measuring module 100 are taken into account when inserting the battery module.

Claims

1. A force measuring module for measuring the force when a battery module is installed in a battery housing, wherein the force measuring module is installed in the battery housing instead of the battery module to measure the force, and the force measuring module comprises: A housing having a shape and outer dimensions of the battery module; as well as at least one force sensor is arranged in the housing and is designed to measure the force and / or the change in force during a first pressing and screwing process of the housing of the force-measuring module into the battery housing, wherein During the second pressing and screwing process of installing the battery module into the battery housing after the force measuring module is removed from the battery housing, the battery module is finally pressed and screwed when the internal stress occurring in the battery cells in the battery module and in the battery housing is minimized based on the force and / or force change measured by the force measuring module during the first pressing and screwing process. 2 . The force measuring module according to claim 1 , comprising at least two force sensors which are spatially distributed in the housing and are each designed to measure a force when the housing is inserted into the battery housing.

3. The force measuring module according to claim 1 or 2, wherein: The structure of the housing is designed for screwing the force-measuring module to the battery housing, wherein the at least one force sensor is designed for measuring a force acting on the force-measuring module when the force-measuring module is screwed to the battery housing.

4. The force measurement module according to claim 1 or 2, wherein: The structure of the housing is configured to screw the force measuring module to a battery housing cover, wherein the at least one force sensor is configured to measure a force acting on the force measuring module when the force measuring module is screwed to the battery housing cover. 5 . The force measuring module according to claim 1 , further comprising a data processing device which is configured to detect and evaluate force sensor signals of the at least one force sensor. 6 . The force measuring module according to claim 1 , further comprising a wireless interface, wherein the wireless interface comprises a WLAN interface, and the WLAN interface is configured to transmit data from the force measuring module to another data processing device. 7 . The force measuring module according to claim 1 , further comprising a container with an energy accumulator, wherein the energy accumulator is configured to supply electrical energy to the force measuring module.

8. A method for determining the force when installing a battery module into a battery housing, comprising: Providing a force measuring module having a housing having the outer dimensions of the battery module and at least one force sensor, the at least one force sensor being arranged in the housing and being configured to measure a force and / or a change in force when the housing of the force measuring module is inserted into the battery housing; Installing the force measuring module into the battery housing instead of the battery module; Measuring the force and / or force change when the force measuring module is installed by the at least one force sensor; Taking the force measuring module out of the battery housing; as well as The battery module is installed into the battery housing, wherein the battery module is finally compressed and screwed when the internal stress occurring in the battery cells in the battery module and in the battery housing is minimized based on the force and / or force change measured by the force measuring module.

9. The method according to claim 8, comprising: The force is measured when the installed force-measuring module is screwed into the battery housing.

10. The method according to claim 8, comprising: The force is measured when the installed force measuring module is screwed onto the battery housing cover.

11. The method according to any one of claims 8 to 10, comprising: The shape and outer dimensions of the battery module are determined, and the shape and outer dimensions of the housing of the force-measuring module are adapted to the shape and outer dimensions of the battery module before the force-measuring module is installed in the battery housing.

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